Adjustable Dumbbell

Abstract

An adjustable dumbbell system including: a base; a plurality of weights configured to rest on the base; an adjustable dumbbell removably secured to the base. The dumbbell includes rotatable handle, a gear mechanism, and two extension members. The rotatable handle is operatively connected to the gear mechanism which extends the extension members along respective extension axes thereof to engage a selection of one or more weights from the base.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Ser. No. 63 / 746,358, filed Jan. 17, 2025, which is incorporated by reference herein in its entirety.

[0002] This application also claims priority to Taiwan Patent Application No. 114129713, filed Aug. 1, 2025, which is incorporated by reference herein in its entirety.BACKGROUND

[0003] Dumbbells are widely used exercise devices for providing resistance training in a wide variety of exercises such as bicep curls, bench presses, shoulder presses, triceps extensions, and the like. Due to the number of exercises that may be performed with dumbbells, users often use many different dumbbells, each with different weights, to perform an exercise routine. Traditional dumbbells are somewhat inconvenient to use because each time one desires to change the weight of the dumbbell, the user either has to select a heavier dumbbell, or disassemble the dumbbell and change the weight.

[0004] In response to these issues, adjustable dumbbells have been designed allowing a user to perform a varied exercise routine without requiring a large number of different weight dumbbells. Some of these adjustable dumbbells include a pair of rods that are slid outward from a mid-portion of the dumbbell near the handle to engage various weight plates to adjust the weight of the dumbbell. These adjustable dumbbells suffer from several drawbacks. For example, each rod is independently controllable and must be set by the user to assure the same number of weight plates, and thus the same amount of weight is coupled to each end of the handle. Failure to set the rods at the same length causes the dumbbell to be asymmetric and can be dangerous to use. Improved exercise devices are needed.BRIEF SUMMARY

[0005] In one embodiment, an adjustable dumbbell system includes a rotatable handle having a grip portion; at least one gear mechanism rotationally coupled to the rotatable handle; and at least one extension member operatively connected to the at least one gear mechanism. Upon rotation of the handle, the at least one extension member extends or retracts along an extension axis to selectively engage at least one weight plate and the handle.

[0006] Optionally in some embodiments, the rotatable handle includes a shaft, the shaft connected to the at least one gear mechanism, the at least one gear mechanism including a plurality of gears configured to cause movement of the at least one extension member upon rotation of the shaft.

[0007] Optionally in some embodiments, the gear mechanism includes a ring gear coupled to an end of the shaft, a respective pinon gear and a respective spur gear configured to mesh with a rack on each respective extension member.

[0008] Optionally in some embodiments, the gear mechanism includes a ring gear coupled to an end of the shaft and at least one of a worm gear or a spur gear configured to mesh with a rack on the extension member.

[0009] Optionally in some embodiments, the at least one gear mechanism includes a first gear mechanism disposed at a first end of the shaft and a second gear mechanism disposed at a second, opposite end of the shaft; the at least one extension member includes a first extension member operatively connected to one of the first gear mechanism or the second gear mechanism, and a second extension member operatively connected to the other of the first gear mechanism or the second gear mechanism; wherein, upon rotation of the handle, the first extension member and the second extension member synchronously extend or retract along respective extension axes to selectively engage at least one respective weight plate and the handle.

[0010] Optionally in some embodiments, the first extension member is disposed at a 3 o'clock, 4 o'clock, 5 o'clock, or 6 o'clock position, and the second extension member is disposed at a 6 o'clock, 7 o'clock, 8 o'clock, or 9 o'clock position with respect to an inner wall of the adjustable dumbbell.

[0011] Optionally in some embodiments, each of the weight plates include a recess adapted to receive the extension member.

[0012] Optionally in some embodiments, the adjustable dumbbell system includes a base including a plurality of positioning walls and positioning recesses configured to align the recess of the weight plates to form a channel that receives each of the extension members.

[0013] Optionally in some embodiments, the at least one extension member is disposed at a 3 o'clock, 4 o'clock, 5 o'clock, 6 o'clock, 7 o'clock, 8 o'clock, or 9 o'clock position with respect to an inner wall of the adjustable dumbbell.

[0014] Optionally in some embodiments, the adjustable dumbbell system includes at least one inner wall disposed at an end of the handle, wherein the handle and the gear mechanism rotate relative to the at least one inner wall.

[0015] Optionally in some embodiments, the adjustable dumbbell system includes a locking mechanism that prevents actuation of the gear mechanism when the dumbbell is disengaged from the base.

[0016] Optionally in some embodiments, the adjustable dumbbell system includes a base including a lock feature configured to engage with locking members on the dumbbell to prevent removal of the handle from the base when weight plates are improperly selected.

[0017] Optionally in some embodiments, the extension members include a plurality of detents configured to assist the user in selecting predetermined weight increments.

[0018] Optionally in some embodiments, the weight plates include opposing grooves and ridges that interlock to prevent dislodgement of the weight plates from the handle when the handle is removed from the base.

[0019] Optionally in some embodiments, the extension members include a stop to prevent overextension beyond a designated length.

[0020] In one embodiment, an adjustable dumbbell system includes a base; a plurality of weight plates configured to rest on the base; an adjustable dumbbell removably secured to the base, the dumbbell including: a rotatable handle, at least two extension members, at least two gear mechanisms, each of the at least two gear mechanisms operatively coupled to a respective one of the at least two extension members. The rotatable handle is operatively connected to the at least two gear mechanisms which extends the extension members along respective extension axes thereof to engage a selection of one or more weight plates from the base.

[0021] Optionally in some embodiments, the rotatable handle includes a shaft, the shaft connected to the at least two gear mechanisms, the at least two gear mechanisms each including a plurality of gears configured to cause synchronous movement of the at least two extension members upon rotation of the shaft.

[0022] Optionally in some embodiments, the at least two gear mechanisms each include a ring gear coupled to an end of the shaft, a pinon gear and a spur gear configured to mesh with a rack on each respective extension member.

[0023] Optionally in some embodiments, the at least two gear mechanisms each include a ring gear coupled to an end of the shaft and a spur gear or a worm gear configured to mesh with a rack on each respective extension member.

[0024] Optionally in some embodiments, each of the weights include a recess adapted to receive the extension member.

[0025] Optionally in some embodiments, the base includes a plurality of positioning walls configured to align the recess of each weight plate to form a channel that receives the extension member.

[0026] Optionally in some embodiments, the adjustable dumbbell system includes a locking mechanism that prevents actuation of the gear mechanism when the dumbbell is disengaged from the base.

[0027] Optionally in some embodiments, the base includes a lock feature configured to engage with locking members on the dumbbell to prevent removal of the handle from the base when weight plates are improperly selected.

[0028] Optionally in some embodiments, at least one of the at least two extension members includes a plurality of detents configured to assist the user in selecting predetermined weight increments.

[0029] Optionally in some embodiments, the weight plates include opposing grooves and ridges that interlock to prevent dislodgement of the weight plates from the handle when the handle is removed from the base.

[0030] Optionally in some embodiments, at least one of the at least two extension members includes a stop to prevent overextension beyond a designated length.

[0031] In one embodiment, a method of adjusting weight in a dumbbell system includes providing a dumbbell having a rotatable handle and two extension members coupled to a gear mechanism; rotating the handle to actuate the gear mechanism, thereby extending the extension members along respective extension axes; and selectively engaging weight plates positioned on opposite ends of the handle via the extension members to adjust a weight of the dumbbell.

[0032] Optionally in some embodiments, the method further includes locking the extension members in a desired position using a locking mechanism when the dumbbell is removed from the base.

[0033] Optionally in some embodiments, the handle rotation simultaneously actuates both extension members to ensure symmetric engagement of weight plates by the extension members.

[0034] In one embodiment, an adjustable dumbbell system includes a base having two opposite ends, and a longitudinal direction defined by the two ends; a plurality of first weight plates configured to rest on one end of the base along the longitudinal direction; a plurality of second weight plates configured to rest on the other end of the base along the longitudinal direction; and a handle assembly arranged between the two ends of the base. The handle assembly includes a handle configured for allowing a user to grasp, having a first end corresponding to the first weight plates and a second end corresponding to the second weight plates; a first end seat and a second end seat respectively connected to the first end and the second end of the handle; at least one enclosure connecting the first end seat and the second end seat along the longitudinal direction, wherein the at least one enclosure is located outside the handle and separated by a distance that does not hinder the user from gripping the handle; and a first extension member and a second extension member, each being operable to extend or retract into the enclosure along the longitudinal direction, the first extension member and second extension member being interconnected to each other, so that the first extension member and the second extension member can be operated to move in opposite directions in the longitudinal direction. The first extension member is operable to extend from the enclosure and the first end seat in a direction away from the second end seat to engage the first weight plates in sequence, and the second extension member is operable to extend from the enclosure and the second end seat in a direction away from the first end seat to engage the second weight plates in sequence, so that the handle assembly is operable to selectively engage the first weight plates and the second weight plates.

[0035] Optionally in some embodiments, the first end seat includes a first transmission mechanism operatively connected to the first extension member to convert a rotational movement into a linear movement of the first extension member in the longitudinal direction; the second end seat includes a second transmission mechanism operatively connected to the second extension member to convert a rotational movement into a linear movement of the second extension member in the longitudinal direction; and the rotational movement of the first transmission mechanism is interconnected with the rotational movement of the second transmission mechanism.

[0036] Optionally in some embodiments, the first extension member is provided with a first rack extending in the longitudinal direction, the first transmission mechanism having at least one first gear, one of the at least one first gear configured to mesh with the first rack on the first extension member; and the second extension member is provided with a second rack extending in the longitudinal direction, the second transmission mechanism having at least one second gear, one of the at least one second gear configured to mesh with the second rack on the second extension member.

[0037] Optionally in some embodiments, one of the at least one first gear of the first transmission mechanism is coaxially connected to one of the at least one second gear of the second transmission mechanism, with a rotation axis corresponding to the longitudinal direction and passing through an interior of the handle.

[0038] Optionally in some embodiments, the handle assembly is provided with a weight selection portion that can be rotated by the user, and rotation of the weight selection portion drives the first gear and the second gear to rotate synchronously; when the weight selection portion is operated to rotate in a forward rotation direction by a predetermined angle, the first extension member can be moved in the direction away from the second end seat by a predetermined distance, while the second extension member can be moved in the direction away from the first end seat by the predetermined distance simultaneously; and when the selection portion is operated to rotate in a reverse rotation direction by the predetermined angle, the first extension member can be moved in a direction close to the second end seat by the predetermined distance, while the second extension member can be moved in a direction close to the first end seat by the predetermined distance.

[0039] Optionally in some embodiments, the handle at least partially forms the weight selection portion, which can rotate about the rotation axis with respect to the first end seat and the second end seat.

[0040] Optionally in some embodiments, the adjustable dumbbell system includes a first auxiliary weight plate and a second auxiliary weight plate resting on predetermined positions of the base, respectively corresponding to locations of the first end seat and the second end seat of the handle assembly when resting on the base; the first end seat and the second end seat respectively provided with a first engaging member and a second engaging member that can be driven by the weight selection portion; wherein the weight selection portion is operable to be rotated to one of a plurality of predetermined angular positions; wherein when the weight selection portion is in some of the predetermined angular positions, the first engaging member and the second engaging member do not engage the first auxiliary weight plate and the second auxiliary weight plate; and wherein when the weight selection portion is in the others of the predetermined angular positions, the first engaging member and the second engaging member respectively engage the first auxiliary weight plate and the second auxiliary weight plate, so that the handle assembly is operable to selectively engage the first auxiliary weight plate and the second auxiliary weight plate.

[0041] Optionally in some embodiments, the first auxiliary weight plate and the second auxiliary weight plate each include a lock portion; the first engaging member and the second engaging member each include at least one convex lump, which can be driven by the weight selection portion to rotate around the rotation axis; when the weight selection portion is in some of the predetermined angular positions, all the convex lumps of the first and second engaging members are not blocked under the respective lock portions of the first auxiliary weight plate and the second auxiliary weight plate; and when the weight selection portion is in the others of the predetermined angular positions, one convex lump of the first engaging member is blocked under the lock portion of the first auxiliary weight plate, and one convex lump of the second engaging member is blocked under the lock portion of the second auxiliary weight plate.

[0042] Optionally in some embodiments, any two adjacent predetermined angular positions of the weight selection portion are separated by one unit angle; when the weight selection portion rotates one unit angle from one of the predetermined angular positions to another one, the handle assembly is operable to be changed from one state of engaging the first and second auxiliary weight plates to another state of disengaging the first and second auxiliary weight plates, or changed from the state of disengaging the first and second auxiliary weight plates to the state of engaging the first and second auxiliary weight plates; when the weight selection portion rotates one unit angle twice in the forward rotation direction from one of the predetermined angular positions to another one, the handle assembly is operable to additionally engage one of the first weight plates and one of the second weight plates; and when the weight selection portion rotates one unit angle twice in the reverse rotation direction from one of the predetermined angular positions to another one, the handle assembly is operable to disengage one of the first weight plates and one of the second weight plates.BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 is an isometric view of an embodiment of adjustable dumbbell system with the adjustable dumbbell resting in a base.

[0044] FIG. 2 is an isometric view of the adjustable dumbbell system of FIG. 1 with the adjustable dumbbell being removed from the base with a selection of weights coupled to the handle assembly of the adjustable dumbbell.

[0045] FIG. 3 is a simplified cross section of the adjustable dumbbell system of FIG. 1 taken along line 3-3 of FIG. 1.

[0046] FIG. 4 is a simplified cross section of an embodiment of weights of the adjustable dumbbell system of FIG. 1 taken along line 4-4 of FIG. 1.

[0047] FIG. 5A is a partial isometric view of the handle assembly of the adjustable dumbbell of FIG. 1 in a first configuration.

[0048] FIG. 5B is a partial isometric view of the handle assembly of the adjustable dumbbell of FIG. 1 in a second configuration.

[0049] FIG. 6 is a simplified cross section of the handle assembly of the adjustable dumbbell of FIG. 1 taken along line 6-6 of FIG. 1.

[0050] FIG. 7A is a simplified cross section of a portion of a locking mechanism of the adjustable dumbbell of FIG. 1 taken along line 6-6 of FIG. 1, in a first configuration.

[0051] FIG. 7B is a simplified cross section of a portion of a locking mechanism of the adjustable dumbbell of FIG. 1 taken along line 6-6 of FIG. 1, in a second configuration.

[0052] FIG. 8A is an enlarged cross-sectional view of a portion of the locking mechanism of the handle assembly of FIG. 1 taken along line 8A-8A of FIG. 7A with the locking mechanism in a first or unlocked position that permits rotation of the discs.

[0053] FIG. 8B is an enlarged cross-sectional view of the locking mechanism of FIG. 8A taken along line 8B-8B of FIG. 8A.

[0054] FIG. 8C is an enlarged cross-sectional view of a portion of the locking mechanism of the handle assembly of FIG. 1 taken along line 8C-8C of FIG. 7B with the locking mechanism is a second or locked position that prevents rotation of the discs.

[0055] FIG. 9A is an isometric view of an embodiment of a handle assembly suitable for use with the adjustable dumbbell system of FIG. 1

[0056] FIG. 9B is an elevation view of the handle assembly of FIG. 9A.

[0057] FIG. 10A is an isometric view of an embodiment of a handle assembly suitable for use with the adjustable dumbbell system of FIG. 1

[0058] FIG. 10B is an elevation view of the handle assembly of FIG. 10A.

[0059] FIG. 11 is a perspective view of a second embodiment of an adjustable dumbbell system with the adjustable dumbbell resting on a base.

[0060] FIG. 12 is a side view of the adjustable dumbbell system of FIG. 11.

[0061] FIG. 13 is a top view of the adjustable dumbbell system of FIG. 11.

[0062] FIG. 14 and FIG. 15 illustrate exploded views of the adjustable dumbbell system of the second embodiment, showing the relative relationship between a handle assembly, weight plates, auxiliary weight plates, and a base.

[0063] FIG. 16 is a perspective view of the adjustable dumbbell system of the second embodiment, showing the handle assembly removed from the base without any weight plates or auxiliary weight plates.

[0064] FIG. 17 is a perspective view of the adjustable dumbbell system of the second embodiment, showing the handle assembly removed from the base and mounted with or connected to all weight plates and auxiliary weight plates.

[0065] FIGS. 18A-18B are cross-sectional views of the adjustable dumbbell system along line I-I of FIG. 12. For clarity of illustration, FIG. 18A illustrates one side of the adjustable dumbbell system (e.g., a left side) along line I-I of FIG. 12, and FIG. 18B illustrates another side of the adjustable dumbbell system (e.g., a right side) along line I-I of FIG. 12, with FIG. 18A and FIG. 18B split across two drawing sheets.

[0066] FIG. 19 is a cross-sectional view of the adjustable dumbbell system along line II-II of FIG. 13.

[0067] FIG. 20 shows an assembly structure of metal components and plastic shell components of the handle assembly of the second embodiment.

[0068] FIG. 21 shows the assembly structure of the handle and the indexing discs of the handle assembly of the second embodiment.

[0069] FIG. 22 is a perspective view of the handle assembly of the second embodiment, removing some of the components and showing the transmission method of a first transmission mechanism.

[0070] FIG. 23 is another perspective view of the handle assembly of the second embodiment, removing some of the components and showing the transmission method of a second transmission mechanism.

[0071] FIG. 24A is a cross-sectional view of the adjustable dumbbell system along line III-III of FIG. 19, wherein an indexing disc is at a predetermined angular position.

[0072] FIG. 24B is similar to FIG. 24A, except that the indexing disc is at another predetermined angular position.

[0073] FIG. 25A is an enlarged view of the indicated portion of FIG. 19, wherein the indexing disc is at a predetermined angular position.

[0074] FIG. 25B is similar to FIG. 25A, but with the indexing disc not positioned at a predetermined angular position.

[0075] FIG. 26 is a side view of the adjustable dumbbell system of the second embodiment, showing the handle assembly mounted with two weight plates and one auxiliary weight plate at each end when removed from the base.

[0076] FIG. 27 is a cross-sectional view corresponding to the adjustable dumbbell system shown in FIG. 26.

[0077] FIG. 28 is an enlarged view of the indicated portion of FIG. 27.

[0078] FIG. 29 is a side view of the adjustable dumbbell system of the second embodiment, showing the handle assembly mounted with three weight plates at each end and without auxiliary weight plates when removed from the base.

[0079] FIG. 30 is a perspective view of a third embodiment of an adjustable dumbbell system, showing a handle assembly mounted with all weight plates and auxiliary weight plates when removed from the base.

[0080] FIG. 31 is a perspective view of the adjustable dumbbell system of the third embodiment, removing some of the components and showing the internal structure of the end seat of the handle assembly and its relationship with the base.

[0081] FIG. 32A is a cross-sectional view of the adjustable dumbbell system of the third embodiment, wherein the handle assembly is placed on the base.

[0082] FIG. 32B is similar to FIG. 32A, but showing the handle assembly removed from the base.

[0083] FIG. 33 illustrates a fourth embodiment of an adjustable dumbbell system, showing a spur gear to worm-rack configuration of adjusting the dumbbell system.

[0084] FIG. 34 illustrates a fifth embodiment of an adjustable dumbbell system, showing a direct worm gear to rack configuration of adjusting the dumbbell system.DETAILED DESCRIPTION

[0085] The present disclosure provides an adjustable dumbbell system which allows a user to select a dumbbell weight. Referring to FIG. 1 and FIG. 2, an adjustable dumbbell system 100 may include an adjustable dumbbell 102 and a base 104. To change the weight of the dumbbell 102, the user may place the dumbbell 102 in the base 104, turn a handle 106 of the dumbbell 102 to engage a desired combination of weight plates 108, and remove the dumbbell 102 from the base 104 to perform a desired exercise.

[0086] The desired combination of weights may be coupled to the handle 106, and unused weights may remain in the base 104. Should the user desire a different dumbbell weight, the user may place the dumbbell 102 back in the base 104, turn the handle 106 to engage the desired weight plates 108, and remove the dumbbell 102 from the base 104 with the desired weight. When the adjustable dumbbell 102 is not in the base 104, for example during exercise-type use, the adjustable dumbbell 102 may be configured such that it is difficult to add or remove weight plates 108.

[0087] The base 104 may receive the dumbbell 102 and may allow a user to adjust the weight of the dumbbell 102. During use of the dumbbell 102, the base 104 may hold the weight plates 108 that are not attached to the dumbbell 102. Before using the dumbbell 102, the user may first determine the weight to be lifted and turn the handle 106 while the dumbbell 102 is in the base 104, causing no weights or one or more weight plates 108 to be fixedly connected to a handle assembly 114. The user may then lift the dumbbell 102 out of the base 104. Any weight plate 108 not fixedly connected with the adjustable dumbbell 102 remains in the base 104. The weight plates 108 may be all the same weight or may have different weights to allow for more flexibility in the user selection of the one or more weight plates 108.

[0088] The base 104 may include a bottom wall 109, one or more positioning walls 110 with positioning recesses 196 therebetween, and a pair of lock features 112. The bottom wall 109 may support the adjustable dumbbell 102 and the weight plates 108. The positioning walls 110 and positioning recesses 196 may ensure that the adjustable dumbbell 102 is properly aligned when it is inserted into the base 104. The positioning walls 110 and / or positioning recesses 196 may hold the weight plates 108 upright and in the proper location relative to the handle assembly 114 so that the adjustable dumbbell 102 may be inserted into and removed from the base 104. The positioning walls 110 may be spaced so as to fit between adjacent weight plates 108 when the dumbbell 102 rests in the base 104 and to keep any weight plate 108 not attached to the dumbbell 102 upright when the dumbbell 102 is removed from the base 104.

[0089] The dumbbell 102 includes a gear mechanism 198 rotatably engaged with the handle, such that as the handle 106 is rotated by the user, while in the base 104, the gear mechanism 198 causes an extension member 179 to move (extend or retract) along an extension axis 191 of the extension member 179 and engage a desired number of weight plates 108. In some embodiments, the dumbbell 102 may have a gear mechanism 198 at each end of the handle 106. In such embodiments, the rotation of the handle 106 causes a synchronous movement of gear mechanisms 198 and thus synchronous movement of the extension members 179 to engage a same number of weight plates 108 at each end of the handle 106.

[0090] The disclosure herein may be applicable to both ends of the dumbbell 102, e.g., the left and right sides thereof. For brevity, only one side of the dumbbell may be described.

[0091] Referring to FIG. 3-FIG. 6, the handle 106 of the adjustable dumbbell 102 may include a grip portion 128 and a rotatable member 132, such as a sleeve or the like. The grip portion 128 may be mounted onto the rotatable member 132 and may be slightly bulged to provide a comfortable and ergonomic surface to grasp to facilitate a user securely gripping the adjustable dumbbell 102. The grip portion 128 may be generally symmetrical about the midpoint of the rotatable member 132. The rotatable member 132 may be coupled (e.g., rotationally coupled) to a shaft 127 that effectuates user selection of the weight plates 108. For example, the dumbbell 102 may include one or more extension members 179 that extend along respective their extension axis 191 to select different weight plates 108 in response to an input from the user to the handle 106.

[0092] The extension members 179 may be at least partially enclosed in respective enclosures 189 (e.g., tubes), or in one enclosure 189 together (see, e.g., FIG. 10A and FIG. 10B). In the embodiment shown for example in FIG. 1-FIG. 7B, the enclosures 189 and / or extension members 179 may be disposed at the 3 o'clock and 9 o'clock positions about the inner walls 169 when dumbbell 102 is viewed from an end (e.g., an elevation view such as shown for example in FIG. 6.) In other embodiments, the enclosures 189 may be disposed at other positions, such as 4 o'clock and 8 o'clock positions, 5 o'clock and 7 o'clock positions, or other positions as desired. For example, the extension members 179 may be disposed at the 3 o'clock and 9 o'clock positions forming a cord the same or nearly the same dimension as the inner wall 169, e.g., may be diametrically spaced apart. In other examples, the extension members 179 may be more closely grouped with one another, e.g., disposed at 4 o'clock and 8 o'clock positions forming a cord with a dimension less than that of the inner wall 169. In such embodiments, the extension members 179 may be disposed in a lower portion of the inner wall 169. In other examples still, the extension members 179 may be even more closely more closely grouped with one another, e.g., disposed at 5 o'clock and 7 o'clock positions forming a cord with a dimension less than that of the 4 o'clock and 8 o'clock positions. In some embodiments, the extension members 179 may be unevenly or asymmetrically spaced about the inner wall 169. In other embodiments still, the extension members 179 may be disposed with at least a portion of the extension members 179 at or near the 6 o'clock position. In some embodiments, the extension members 179 may be disposed at the 5:30 and 6:30 positions (e.g., with one extension member 179 at an hour hand position and another extension member 179 at a minute hand position of a clock face).

[0093] See e.g., FIG. 9A-FIG. 10B showing alternate embodiments with placements of the extension members 179 and / or enclosures 189 such as to facilitate user access to the handle 106.

[0094] The shaft 127 may be received through a generally circular passage defined by the rotatable member 132. Each end portion 130 of the shaft 127, one on either end of the rotatable member 132, may extend beyond a respective end of the rotatable member 132. The rotatable member 132 may be rotatable about a longitudinal axis 134 of the shaft 127 to allow a user to select a desired dumbbell weight plate 108 by rotating the handle 106. In many embodiments, the rotatable member 132 and the shaft 127 may rotate in unison about the longitudinal axis 134 of the shaft 127.

[0095] With particular reference to FIG. 3, the shaft 127 may be coupled to bearings 171 e.g., at the end portions 130. For example, an inner race of the bearings 171 may be coupled to the shaft 127 while an outer race of the bearings 171 is coupled to the inner walls 169, thus allowing relative rotational movement between the handle 106, the rotatable member 132, the grip portion 128, and / or the shaft and the inner walls 169.

[0096] With particular reference to FIG. 5A and FIG. 5B, the shaft 127 or the bearings 171 may be coupled to respective gear mechanisms 198. The gear mechanisms 198 may include ring gears 173, pinons 175, spur gears 177, and / or a rack 181 formed with or coupled to the extension members 179. In some embodiments, one or more components of the gear mechanism 198 may be optional, may be replaced with other components, or include additional components. In some embodiments, the gears of the gear mechanism 198 may be replaced with toothless discs, pulleys, belts, or other devices. For example, the ring gears 173 may rotate in unison with the shaft 127. The ring gears 173 may be bevel gears with teeth suitable to mesh with and drive other gears or components. A pinon 175 may be rotationally mounted to the inner wall 169 such that its teeth mesh with those of the ring gear 173 and the pinon 175 may be driven by the ring gear 173 about a rotation axis. 193. A spur gear 177 may be mounted, and rotatable with, the pinon 175 such that the spur gear 177 and the pinon 175 rotate in unison about the rotation axis 193. The teeth of the spur gear 177 mesh with corresponding teeth of a rack 181 formed with or coupled to the extension member 179

[0097] As shown for example in FIG. 5A and FIG. 5B, as the user rotates the handle 106, the shaft rotates with the handle 106 about the longitudinal axis 134. FIG. 5A shows example alignment marks stationary mark 502 and a rotational mark 504. These marks may not be included in the actual dumbbell 102, but are shown to illustrate the mechanism of action of the dumbbell 102 to enable a user to select different weight plates. In FIG. 5A, the stationary mark 502 and the rotational mark 504 are substantially aligned. The extension members 179 are retracted within enclosures 189 coupled to the inner walls 169 and disposed about the ring gear 173. In the configuration of FIG. 5A, no weight plates 108 may be selected. As a user rotates the handle 106, and thus the shaft 127, (e.g., counterclockwise as shown in FIG. 5A) the ring gear 173 rotates in the same direction as the handle 106, e.g., in a rotation direction 195 about the longitudinal axis 134 either or both clockwise and / or counterclockwise. The teeth of the ring gear 173 mesh with corresponding teeth of the pinon 175 causing the pinon 175 to rotate about the rotation axis 193. The spur gear 177 rotates with the pinon 175. In some embodiments, the pinon 175 and the spur gear 177 may be combined (e.g., with one set of teeth). The teeth of the spur gear 177 mesh with the teeth of the rack 181 and as the spur gear 177 rotates about the rotation axis 193 causing the extension member 179 to extend away from the middle portion of the dumbbell 102. See, e.g., FIG. 5B, showing both extension members 179 in an extended position suitable to engage weight plates 108. See also, FIG. 2 showing the extension member 179 engaging with the recess 183 formed in the weight plates 108. Optionally in some embodiments, one or more of the extension members 179 may include a detent 140 (see FIG. 5A and FIG. 5B) or similar mechanism to aid in selecting a discrete weight plate 108 selection. For example, the extension member 179 may include a plurality of notches and the handle assembly 114 may include a biased rolling member like a ball that “clicks” or “snaps” into place when the extension member 179 is at the appropriate extension to select a weight. In some embodiments, the extension members 179, the ring gear 173, the indexing disc 120 or another portion of the handle assembly 114 may include a stop to prevent overextension of the extension members 179 beyond a desired length.

[0098] As shown for example in FIG. 5B, the rotation of the handle 106 simultaneously or synchronously causes movement of both extension members 179 (via the opposing ring gears 173, pinons 175 and spur gears 177 at each end of the dumbbell 102) a same amount along their respective extension axes 191. Thus, with a single rotation of the handle 106, the user can select the same amount of weight on each end of the dumbbell, which is a significant advantage in ease of use and speed compared to existing adjustable dumbbells.

[0099] With reference to FIG. 3 and FIG. 4, when the handle assembly 114 is removed with a weight plate 108 selection from the base 104, the weight plates 108 are secured to the handle assembly 114. In the vertical direction, the weight plates 108 are held to the handle assembly 114 by the interaction of the extension member 179 and the recess 183 formed in the weight plates 108. E.g., each weight plate 108 has a notch or recess formed therein. The recess 183 may be located at an edge of the weight plate 108 or may be located in the main body of a weight plate 108, not touching the outer edge of the weight plate 108. When the weight plates 108 are resting in the base 104 (e.g., against the positioning walls 110), the recesses 183 align with one another to form an elongated channel that receives varying lengths of the extension member 179 based on the handle 106 position. In the extension direction (e.g., left and right along the extension axis 191) each weight plate is secured to a subsequent weight plate. See e.g., FIG. 4 showing each weight plate 108 having a ridge 187 on one face thereof and a corresponding groove 185 on another, opposite face thereof. When resting in the base or attached to the handle assembly 114, the ridge 187 of one plate slides into the groove 185 of the plate next to it and so forth, thereby securing the weight plates 108 to the handle assembly 114. In the example shown, the groove 185 and ridge 187 form a dovetail arrangement, with the ridge 187 having a flared portion extending laterally that prevents the ridge 187 from being pulled along the extension axis 191 direction out of the groove 185 of the adjacent weight plate 108. In some embodiments, the notches and or recesses may be v-shaped to help further secure weight plates from relative vertical movement when the dumbbell 102 is removed from the base.

[0100] The handle assembly 114 has several advantages over existing adjustable dumbbells. For instance, with a single user input (e.g., rotation of the handle 106), the user can select weight plate 108 on both ends (e.g., left and right ends) of the dumbbell 102. With many existing adjustable dumbbells, the user must separately select weight on each end of the dumbbell, which is time-consuming, and prone to error. Furthermore, some existing adjustable dumbbells have a handle assembly that extends the same distance regardless of which weights are selected. In other words, such dumbbells are the same length regardless of whether 2 kg or 25 kg is selected. This makes such dumbbells awkward to use for some exercises.

[0101] Furthermore, the adjustable dumbbell system 100 disclosed herein is advantageous over existing dumbbells because the dumbbell 100 includes a locking mechanism 142 that prevents a user from removing the handle assembly 114 from the base 104 when an extension member 179 is between weight selections, and prevents a user from retracting or extending the extension members 179 when the handle assembly 114 is off the base, e.g., to avoid dropping weight plates during an exercise, which is a potential safety hazard.

[0102] Referring to FIG. 7A-FIG. 8C, the adjustable dumbbell system 100 includes a locking mechanism 142 that serves at least two purposes. First, the locking mechanism 142 prevents a user from removing the dumbbell 102 from the base 104 when the handle 106 is positioned between weight selections, e.g., one or more weight plates 108 are partially, but not fully engaged with the dumbbell 102. This function prevents partially selected weights from falling or snagging on the base 104 or other portion of the adjustable dumbbell system 100.

[0103] After a user has fully selected a weight and lifted the dumbbell 102 from the base 104 (e.g., As shown for example in FIG. 2), the locking mechanism 142 prevents the user from changing the weight plate 108 selection while the dumbbell 102 is not secured on the bottom wall 109. This feature prevents the user from dropping weight plates 108 while the dumbbell 102 is in use. In some embodiments, the locking mechanism 142 and related mechanisms and components may be as described in U.S. Patent Publication US 2015 / 0360073, which is hereby incorporated by reference herein in its entirety and for all purposes.

[0104] The locking mechanism 142 includes lock features 112. The lock features 112 may be formed from a relatively rigid metal, plastic, or other suitable material. Each lock feature 112 may extend upwardly from the base 104, e.g., from the bottom wall 109. In some embodiments, each lock feature 112 may include a plate-like vertical portion that extends upwardly from the base 104 with a plate-like horizontal portion that extends substantially perpendicular from an end portion of the vertical portion that is distal from the base 104. The arrangement of the vertical and horizontal portions of each lock feature 112 may resemble an L-shaped profile for the portion of the lock feature 112 extending above the base 104. The lock features 112 may be positioned on the base 104 to extend into a cavity formed in the adjustable dumbbell 102 when the dumbbell 102 is placed in the base 104. The lock features 112 may deactivate a locking mechanism, as described further below, to allow selection of different weights when the adjustable dumbbell 102 is in the base 104. In some embodiments, the locking mechanism 142.

[0105] The handle assembly 114 may include an inner cover 118 (shown in dashed lines in FIG. 1 and the details of FIG. 8A and FIG. 8B) that encloses or hides a portion of the locking mechanism 142. The handle assembly 114 may include indexing discs 120 which may be mounted onto the handle 106 immediately distal or outside of the inner covers 118, e.g., on an inner wall 169. The inner covers 118 or inner walls 169 may include a locking mechanism 142 that permits or prevents rotation of the handle 106. The locking mechanism 142 may include a locking member 144, such as a spring-loaded button. The locking member 144 may include an interference feature 145, such as a protrusion or a projection, which extends in a distal direction parallel or generally parallel to a longitudinal axis 134 of the handle 106 or the shaft 127 and toward the indexing discs 120. The locking member 144 may be vertically movable relative to the inner covers 118 and / or inner wall 169 and may be laterally restrained in directions oriented transversely (e.g., orthogonally) to the direction of movement, such as in a rotation direction of the ring gear 173.

[0106] Turning to FIG. 8A, the locking member 144 may be downwardly biased toward an opening 148 by a lock bias member 146, such as a spring, which may be arranged along a vertically oriented axis. The opening 148 may be defined by the inner cover 118 and / or the inner wall 169. The opening 148 may be downwardly extending to expose a lower surface of the locking member 144 to permit a portion of the base 104 to engage and vertically displace the locking member 144 against the bias of the lock bias member 146. The locking member 144 may be vertically displaced within a cavity 150 defined by the inner cover 118. The inner covers 118 may include cover plates 152, which may be removably attached to the inner or proximal surface of the inner covers 118 to provide access to the locking members 144 and the lock bias members 146. The cover plates 152 may also provide a bearing surface for the locking members 144 to slide along during vertical displacement of the locking members 144 relative to the inner covers 118.

[0107] Referring to FIG. 8A-FIG. 8C, the locking mechanism 142 of the inner cover 118 may be biased to engage an associated lock feature 154 to prevent the indexing discs 120 from rotating about the longitudinal axis of the shaft 127 and / or relative to the weights 108 when the handle assembly 114 of the dumbbell 102 is removed from the base 104. Upon removal of the handle assembly 114 from the base 104, each locking member 144 interferes with a respective indexing disc 120 to prevent rotation of the indexing discs 120. This interference may occur by each locking member 144 engaging the lock feature 154 on a respective indexing disc 120. In some implementations, such as implementations in which the lock feature 154 is two or more teeth and the interference feature 145 is a protrusion, upon removal of the dumbbell 102 from the base 104, lock bias members 146 bias respective locking members 144 into a locking position in which each locking member's protrusion is disposed between adjacent teeth of respective indexing discs 120, thereby preventing rotation of the indexing discs 120, and hence rotation of the separator discs and the selector discs 122, relative to the weights 108.

[0108] Referring to FIG. 7A-FIG. 8C, when the dumbbell 102 is placed in the base 104, the locking mechanism 142 may be moved into a disengaged or unlocked position. Upon placement of the dumbbell 102 onto the base 104, the lock feature 112 of the base 104 disengages the locking mechanism 142 from the lock feature 154 of the indexing disc 120 to allow rotation of the indexing disc 120 about the longitudinal axis of the shaft 127 and / or relative to the weight plates 108. In some embodiments, the lock feature 112 of the base 104 may extend upwardly through the opening 148 of the inner cover 118 and may drive the locking mechanism 142 upwardly. The lock feature 112 may move the locking member 144 upwardly a sufficient distance to displace the interference feature 145 (e.g., a protrusion, projection, or the like) from the rotational path of the lock feature 154 (e.g., teeth or the like) of the indexing disc 120 so that the indexing disc 120 may be turned to adjust the weight of the adjustable dumbbell 102. Thus, when the dumbbell102 is seated in the base 104, the weight of the adjustable dumbbell 102 may be adjusted by turning the rotatable member 132 of the handle 106 to selectively engage or disengage the weight plates 108 with the indexing discs 120.

[0109] The adjustable dumbbell 102 may not be removed from the base 104 unless the weight plates 108 have a predetermined level of engagement or disengagement with the indexing discs 120 and the extension members 179. The removal of the adjustable dumbbell 102 from the base 104 may be prevented when the base's lock feature 112 engages with the lock features 154 of the indexing disc 120 based on a rotational orientation of the handle 106. In some implementations of this locking system, the lock feature 154 for each indexing disc 120 may rotate beneath an upper portion 167 of a respective lock feature 112 when the dumbbell 102 is placed in the base 104. For embodiments in which the lock feature 154 is teeth, the teeth may be circumferentially spaced apart sufficiently to allow the upper portion 167 of the lock feature 112 to pass between adjacent teeth when the indexing discs 120 and extension members 179 are positioned at respective predetermined rotational (e.g., in a rotation direction 195) and extensional positions (e.g., along the extension axis 191) relative to the weight plates 108 to permit removal of the dumbbell 102 from the base 104. Additionally, the teeth may be circumferentially spaced apart sufficiently to inhibit the upper portion 167 of the lock feature 112 from passing between adjacent teeth 154 when the indexing discs 120 are not positioned at predetermined rotational positions relative to the weight plates 108 to prevent removal of the dumbbell 102 from the base 104, thus effectively locking the dumbbell 102 to the base 104. The predetermined rotational positions may be selected so that any weight plate 108 that is intended to be fixedly joined to the handle assembly 114 based on the relative rotational positions of the indexing discs 120 to the weight plates 108 is sufficiently engaged with its respective indexing disc 120.

[0110] When the weight plates 108 are not engaged with or disengaged from the indexing discs 120 as desired, a tooth of the indexing disc 120 may engage the upper portion 167 of the lock feature 112 and prevent the lock feature 112 from exiting through the opening 148 of the inner cover 118, thus locking the dumbbell 102 to the base 104. When the indexing discs 120 are properly aligned rotationally, the extension members 179 are aligned properly with the weights in the recess 183, the upper portion 167 of the lock feature 112 may pass between adjacent teeth 154, and the dumbbell 102 may be removed from the base 104. During removal of the dumbbell 102 from the base 104, the lock bias member 146 may bias the locking member 144 downwardly such that the interference feature 145 interacts with the indexing disc's lock feature 154 to prevent the indexing discs 120 from rotating relative to the inner covers 118, inner walls 169, and the weight plates 108. Thus, when removed from the base 104, the weight of the dumbbell 102 may be fixed until the dumbbell 102 is repositioned onto the base 104 to select a different combination of weights.

[0111] When the dumbbell 102 is set into the base 104, the lock feature 112 may engage the locking member 144 to disengage the locking member 144 from the indexing discs 120. The handle 106 may then be rotated to rotate the ring gear 173, pinon 175, and spur gear 177, and extend or retract the extension members 179 to select the desired number of weight plates 108. The detents 140 (see, FIG. 5A and FIG. 5B) may help the user identify when the dumbbell 102 is at a secure location rotationally and not between locations for selecting weight plates 108. The indicator markings 166 on the indexing disc 120 may be visible through a window to indicate that the desired weight is selected (see FIG. 8A-FIG. 8C). In between weight selection locations, the lock feature 154 on the indexing discs 120 may engage the lock feature 112 on the base 104 to prevent the dumbbell 102 from being removed from the base 104. When the indexing discs 120 are in a proper rotational orientation, the base's lock feature 112 does not engage the indexing disc's lock feature 154, thus allowing the dumbbell 102 to be removed from the base 104.

[0112] As the dumbbell 102 is removed from the base 104, the base's lock feature 112 ceases to engage the locking member 144, thus allowing the locking member 144 to be biased into a locking position in which the interference feature 145 interacts with the indexing disc's lock feature 154 to keep the indexing discs 120 from rotating relative to the weight plates 108. The locked nature of the indexing discs 120 may prevent independent rotation of the indexing disc 120 and thus extension or retraction of the extension members 179, via the ring gear 173, pinon 175 and spur gear 177, since the indexing disc 120 may be rotationally locked with the ring gear 173. Thus, when the dumbbell 102 is removed from the base 104, the indexing discs 120 are not rotatable, and the extension members 179 not moveable along the extension axis 191 to change the weight selection or cause the weight plates 108 on the dumbbell 102 to become dislodged. The lock feature 154 may be positioned proximate to the periphery of the indexing disc 120. In some embodiments, the lock feature 154 may be castellated teeth arranged around the perimeter 161 of the indexing disc 120. Each tooth may extend towards the inner covers 118 in a direction parallel, or generally parallel, to a longitudinal axis 134 of the handle 106 and / or shaft 127 and / or the extension axis 191 of the extension members 179.

[0113] FIG. 9A and FIG. 9B show an embodiment of the handle assembly 114 where the extension members 179 are disposed at a lower portion of the inner walls 169 (e.g., at 5 o'clock and 7 o'clock positions). This embodiment facilitates easier grasping of the handle 106 by the user by placing the extension members 179 and their enclosures 189 lower on the dumbbell 102.

[0114] FIG. 10A show an embodiment of the handle assembly 114 where the extension members 179 are disposed at a lower portion of the inner walls 169 (e.g., at a 6 o'clock position). This embodiment also facilitates easier grasping of the handle 106 by the user by placing the extension members 179 and their enclosures 189 lower on the dumbbell 102. This embodiment also has fewer parts as both extension members 179 may be enclosed in a single enclosure 189, and thus may be less costly to produce.

[0115] FIGS. 11, 12 and 13 are respectively a perspective view, a side view and a top view of an adjustable dumbbell system 200 (hereinafter, sometimes simply referred to as an adjustable dumbbell) in a standby state according to a second embodiment of the present invention. With additional reference to FIG. 14 and FIG. 15, the adjustable dumbbell system 200 includes a base 210, a plurality of first weight plates 220A, a plurality of second weight plates 220B, a first auxiliary weight plate 225A, a second auxiliary weight plate 225B and a handle assembly 202, or a combination thereof, that can be separated or combined with each other. In terms of weight selection function, the user can selectively attach the first and second weight plates 220A, 220B (hereinafter, sometimes simply called weight plates) and / or the first and second auxiliary weight plates 225A, 225B (hereinafter, sometimes simply called auxiliary weight plates) to the handle assembly 202 according to the user's personal needs, so that the user is able to grasp the adjustable dumbbell with the required weight to perform weight training. In some cases, FIG. 16 shows that the handle assembly 202 does not mount any weight plates 220A, 220B or auxiliary weight plates 225A, 225B, forming the lightest dumbbell 204; and FIG. 17 shows that the handle assembly 202 mounts all weight plates 220A, 220B and auxiliary weight plates 225A, 225B, forming the heaviest dumbbell 204.

[0116] The base 210 is elongated as a whole and can be placed horizontally (e.g., flat or relatively flat) on a plane such as the ground, floor, stand, table or a desktop. The base 210 may define a longitudinal direction (i.e., the relative direction of two opposite ends of the base 210, corresponding to the x-axis in FIGS. 11 to 13), a width direction (corresponding to the z-axis in FIGS. 11 and 13), and a height direction (corresponding to the y-axis in FIGS. 11 and 12) that are perpendicular to one another. Although the spatial relationships of the handle assembly 202, the weight plates 220A, 220B and the auxiliary weight plates 225A, 225B relative to the base 210 may change (for example, when a user lifts up the dumbbell 204 for weight training) , in order to facilitate the explanation of the structure of each component and the cooperation relationship between them, the aforementioned longitudinal direction, width direction and height direction will be applied to the handle assembly 202, the weight plates 220A, 220B, and the auxiliary weight plates 225A, 225B hereinafter according to the corresponding relationship in the standby state as shown in FIGS. 11 to 13. For example, unless otherwise specified, the terms “above”, “below”, “top side”, “bottom side” or similar terms below are based on the aforementioned height direction (y-axis) in the standby state. In addition, the “inner side” in the longitudinal direction (x-axis) refers to the side close to the center of the base 210 in the standby state, and the “outer side” refers to the side away from the center of the base in the standby state.

[0117] Next, the detailed structures of the base 210, weight plates 220A, 220B, auxiliary weight plates 225A, 225B, and the handle assembly 202 and their coordination will be described in order. If necessary, please refer to FIG. 18A18B and FIG. 19, which are horizontal (x-z plane) and vertical (x-y plane) cross-sectional views of the adjustable dumbbell system 200 in the standby state shown in FIG. 11.

[0118] Referring to FIG. 17, the base 210 can be divided into two opposite halves that are mirror-symmetric. At the terminal ends of the base 210, there are two side walls 211 facing each other. As shown in FIG. 19, a handle portion 212 is formed on the outside of the top of each side wall 211 to facilitate the user in moving the entire adjustable dumbbell system with two hands. The inner side of each side wall 211 has a protrusion 213 extending upward from the bottom of the side wall 211. The width of the protrusion 213 in the width direction gradually decreases from bottom to top, and its horizontal cross section has a dovetail shape, as depicted in FIG. 18A. Each half of the base 210 has a positioning recess 214 disposed on the inner side of the base 210, and a bump 215 located at the center of the outer side of the positioning recess 214. A hook 216 formed by a bending metal sheet is mounted between the bump 215 and the positioning recess 214, and the exposed part of the hook 216 extends upward and then extends inward, forming an inverted L shape when viewed from the side.

[0119] Referring to FIG. 14, the adjustable dumbbell system 200 includes five first weight plates 220A and five second weight plates 220B. The first weight plates 220A and the second weight plates 220B have identical shapes and structures, which are approximately circular in shape. In practice, each weight plate may be made of a plastic-coated metal sheet, or may be an integrated metal part or combined with plastic parts. Weight plates 220A, 220B are shown in cross section in FIGS. 18, 19, and 27 generally. However, the specific cross-sectional structures of the weight plates 220A, 220B are omitted in the cross-sectional views. One side surface (outer side surface) of each weight plate 220A, 220B has a groove 221 extending upward from the bottom edge. The width of the groove 221 in the width direction gradually decreases from bottom to top, and its horizontal cross section is dovetail-shaped, as depicted in FIG. 18B. Corresponding to the groove 221, the other side surface (inner side surface) of each weight plate 220A, 220B has a ridge 222 extending upward from the bottom edge. The width of the ridge 222 in the width direction gradually decreases from bottom to top, and its horizontal cross section is dovetail-shaped, as depicted in FIG. 18. In addition, each weight plate 220A, 220B has a recess (or notch) 223 formed on a predetermined side according to the width direction. The recess 223 passes through each weight plate 220A, 220B from the inner side surface to the outer side surface in the longitudinal direction, and its cross section is generally rectangular. In this embodiment, the recess 223 may recess from the side edge of each weight plate 220A, 220B towards to the center. In other embodiments, the recess 223 of the weight plate may be a through hole with a complete inner circumference (e.g., a rectangular hole with four walls), not touching the outer edge of the weight plate. Each first weight plate 220A and each second weight plate 220B may have the same predetermined weight, which is set to 5 pounds (about 2.27 kg) in this embodiment.

[0120] In the standby state as shown in FIGS. 11 to 13, the five weight plates (referred to as the first weight plates) 220A are arranged at one end of the base 210 along the longitudinal direction, and the other five weight plates (referred to as the second weight plates) 220B are arranged at the other end of the base 210 along the longitudinal direction. Each weight plate 220A, 220B is placed upright, having the side surface (i.e., the inner side surface) with the ridge 222 facing the center of the base 210, and the side surface (i.e., the outer side surface) with the groove 221 facing away from the center of the base 210. The first weight plate 220A and the second weight plate 220B, located on the outermost sides, respectively abut against the two side walls 211 at the terminal ends of the base 210, and the grooves 221 on the outer sides of the weight plates 220A, 220B are engaged with the protrusions 213 on the inner sides of the side walls 211. At the same time, any two adjacent first weight plates 220A or any two adjacent second weight plates 220B are engaged with each other through the grooves 221 and the ridges 222, so that the opposite sides of the adjacent two weight plates are appropriately against each other and their outer edge are overlapped. Thus, the first weight plates 220A are neatly placed between the side wall 211 and the bump 215 on one half of the elongated base 210, and the recesses 223 of the first weight plates 220A are all aligned on one side according to the width direction to form a first channel 224A extending along the longitudinal direction, as shown in the lower portion of FIG. 13. The second weight plate 220B are neatly placed between the side wall 211 and the bump 215 on the other half of the elongated base 210, and the recesses 223 of the second weight plates 220B are all aligned on the other side according to the width direction to form a second channel 224B extending along the longitudinal direction, as shown in the upper portion of FIG. 13.

[0121] Based on the aforementioned engagement structure, any weight plate 220A, 220B on the base 210 can be moved upward along the extension direction of the groove 221 and detached from the other weight plate 220A, 220B on the base 210 located on its outer side or the side wall 211. Similarly, the weight plate 220A, 220B outside the base 210 can allow the groove 221 on its outer side to align and move downward to engage the ridge 222 on the inner side of the other weight plate 220A, 220B on the base 210 or the protrusion 213 on the inner side of the side wall 211, allowing the weight plate to return to the preset position of the standby state. Referring to FIGS. 18A-18B, since the concave and convex locking features between the adjacent two weight plates are dovetail-shaped, the two weight plates cannot be separated in other directions other than in the height direction. In the present embodiment, the grooves 221, the ridges 222 and the protrusions 213 are designed to gradually narrow from bottom to top to facilitate engagement and separation, and the engagement can be tight. In other embodiments, each weight plate may be provided with a groove (e.g., gradually narrowing downward from the top edge) on the inner side, and a ridge on the outer side that matches the groove. In addition, embodiments may adopt a weight plate interlocking structure similar to that disclosed in U.S. Pat. Nos. 9,643,042 or 6,149,558, or using a plurality of connecting rods extending along the longitudinal direction to connect the symmetrically positioned first weight plates and second weight plates in pairs, similar to the U.S. Pat. No. 7,090,625.

[0122] Referring to FIG. 15, the shape and structure of the first auxiliary weight plate 225A and the second auxiliary weight plate 225B are entirely the same, and their appearance is similar to a U-shaped plate. Similarly, in practice, the auxiliary weight plates may be made of a plastic-coated metal sheet, or may be an integrated metal part or combined with other plastic parts. Each auxiliary weight plate 225A, 225B has a lock portion 226 protruded outward approximately in the center of one side (outer side) thereof. The first auxiliary weight plate 225A and the second auxiliary weight plate 225B may have the same predetermined weight. In the present embodiment, the weight of the first and second auxiliary weight plates is set at 2.5 pounds (about 1.13 kg), namely one-half the weight of each weight plate 220A, 220B. Referring to FIG. 16 and FIG. 19, in the standby state, the two auxiliary weight plates 225A, 225B are respectively inserted upright in the two positioning recesses 214 of the base 210 with U-shaped openings 227 facing upward, and each of them has its side (outer side) where the lock portion 226 is located, facing away from the center of the base 210. One of the two auxiliary weight plates 225A, 225B located at the same side of the base 210 as the first weight plate 220A may be called the first auxiliary weight plate 225A, and the other one of the two auxiliary weight plates 225A, 225B located at the same side of the base 210 as the second weight plate 220B may be called the second auxiliary weight plate 225B. In order to ensure that the auxiliary weight plates 225A, 225B are inserted into the aforementioned positioning recess 214 with the correct face, a concave portion 228 is formed in the center of the bottom of the outer side of each auxiliary weight plate 225A, 225B (see FIG. 15.), which can match the shape of a convex portion 217 on the outer side of the bottom of the positioning recess 214 when the auxiliary weight plates 225A, 225B are correctly inserted (see FIG. 19 and FIG. 25A).

[0123] Referring to FIG. 16, the handle assembly 202 includes a handle 230 extending along the longitudinal direction, two end seats 240A, 240B respectively connected to the two opposite ends of the handle 230, and two guide tubes (or enclosures) 260 located on two opposite sides of the handle 230 and connected to the two end seats 240A, 240B along the longitudinal direction. In another example, the handle assembly 202 may include at least one enclosure or guide tube 260 connecting the end seats 240A, 240B along the longitudinal direction. In addition, the handle assembly 220 also includes numerous internal components that are not visible from the outside, which will be described in detail later. First, referring to FIG. 20, the basic frame of the handle assembly 202 is composed of several metal components and several of plastic shell components. The metal components may include an axle tube 231, two side plates 241 and the two guide tubes 260. The axle tube 231 extends straight along the longitudinal direction and has a circular cross section. The two side plates 241 are connected to the opposite ends of the axle tube 231 in a vertical manner. Specifically, each side plate 241 is substantially a circular plate, and an engaging block 242 that engages with the end of the axle tube 231 is locked at an approximate central position of its inner side. Each side plate 241 has two square holes 243 located on opposite sides in the width direction. The two guide tubes 260 are located at opposite sides of the axle tube 231 in the width direction, and each guide tube 260 is separated from the axle tube 231 by a predetermined distance and extends straight along the longitudinal direction. The cross sections of the two guide tubes 260 are substantially square or rectangular. Each guide tube 260 has two ends protruding through the respective square holes 243 in the respective side plates 241, and each guide tube 260 is secured to the two side plates 241 by welding around the corresponding square holes 243. Furthermore, each guide tube 260 has two guiding members 261 respectively welded to one side that faces the axle tube 231. The two guiding members 261 are located near the two ends of each guide tube 260 and extend in the height direction. Each guide tube 260 has an aperture 262 at the top of one end thereof.

[0124] The plastic shell components may include two outer shells 244, two upper shells 245 and two lower shells 246. The two outer shells 244 are respectively mounted on the outer sides of the two side plates 241. The two upper shells 245 are respectively mounted on the upper portions of the inner sides of the two side plates 241. The two lower shells 246 are respectively mounted on the lower portions of the inner sides of the two side plates 241. In detail, each outer shell 244 is substantially a circular plate, and the contour of its outer edge matches the side plate 241, and it is abutted and secured to the outer side of the side plate 241. Each outer shell 244 has a through hole 247 corresponding to one square hole 243 of the corresponding side plate 241. The through holes 247 of the two outer shells 244 are located on different sides in the width direction. In other words, the through hole 247 of one outer shell 244 is connected to the opening of one of the guide tubes 260, and the through hole 247 of the other outer shell 244 is connected to the opening of the other guide tube 260. In addition, the outer side surface of each outer shell 244 has a groove 248 extending upward from the bottom edge. The width of the groove 248 in the width direction gradually decreases from bottom to top, and its horizontal cross section is dovetail-shaped, as depicted in FIG. 18A. On the other hand, the upper shell 245 and the lower shell 246 on the inner side of each side plate 241 are aligned up and down, and each uses a plurality of screws (not shown) passing through the side plate 241 to lock with the corresponding outer shell 244, so that the upper shell 245 and the lower shell 246 can be fixed with respect to the side plate 241, and form a chamber 249 on the inner side of the side plate 241, as shown in FIG. 19. Both the apertures 262 and the guiding members 261 of the guide tubes 260 are located in the respective chambers 249. Each upper shell 245 has a window 251 at the center of the top. Each lower shell 246 has a large opening 252 at the inner side and a small opening 253 at the outer side.

[0125] Referring to FIG. 21, the handle 230 is substantially a tubular member with an axial hole whose inner diameter matches the outer diameter of the axle tube 231, so that the handle 230 can be pivotably mounted on the exterior of the axle tube 231, allowing it to rotate in place relative to the axle tube 231 about a rotation axis A1 (as shown in FIGS. 18A-18B or FIG. 19, at the center of the axle tube 231). The handle 230 cannot be moved axially relative to the axle tube 231. The middle section of the handle 230 forms a grip portion 232 that the user can grasp with one hand. To improve grip comfort, a rubber layer can be applied to the grip portion 232. As shown in FIG. 19, the two ends of the handle 230 are located within the two chambers 249. In the present embodiment, the side plate 241, the outer shell 244, the upper shell 245 and the lower shell 246 at each end of the handle 230 together constitute the end seats 240A, 240B, which are used to enclose various mechanisms described below.

[0126] As shown in FIG. 21, each of the two ends of the handle 230 is connected to an indexing disc 233 in a way that cannot rotate relative to each other, so that rotation of the handle 230 about the rotation axis A1 forces the two indexing discs 233 to rotate synchronously. Each indexing disc 233 is enclosed between the respective upper shell 245 and the lower shell 246. Each indexing disc 233 is made up of an annular plate that is coaxial with the axle tube 231 and is pivotably mounted on the axle tube 231 through a central hole 234. Each indexing disc 233 has at least one convex lump 235, such as multiple convex lumps 235. In one example, each indexing disc 233 includes six convex lumps 235 equiangularly disposed on its inner side (around the rotation axis A1), and twelve teeth 236 protruding outward and equidistant around the outer periphery of the outer side of the indexing disc 233. Moreover, each indexing disc 233 has twelve positioning holes 237 equiangularly distributed in a relatively outer circle of the indexing disc 233, and twelve ball sockets 238 equiangularly distributed in a relatively inner circle of the indexing disc 233. The ball sockets 238 correspond to the positions of the positioning holes 237. Each of the teeth 236 is located in the middle position of the angle between the adjacent two positioning holes 237. For example, there are one positioning hole 237 and one ball socket 238 at each of the twelve orientations of the disc (around the rotation axis A1), that is, one o'clock, two o'clock, three o'clock, . . . , and twelve o'clock, while the teeth 236 are located at twelve orientations (hour hand), that is, one-thirty, two-thirty, three-thirty, . . . , and twelve-thirty. On the other hand, referring to FIG. 24A, the six convex lumps 235 are distributed in positions corresponding to six equally spaced positioning holes 237. For example, the convex lumps 235 are only present at six positions: one o'clock, three o'clock, five o'clock, . . . , and eleven o'clock. Furthermore, each indexing disc 233 has twelve weight indicators 239 distributed equally spaced around the outer periphery of the indexing disc 233. The positions of these weight indicators 239 also correspond to the positioning holes 237. The values indicated by these weight indicators 239 are “5”, “10”, “15”, . . . , “50”, “55” and “60”, that is, arithmetic arrangement from the minimum value “5” to the maximum value “60”, and each level is incremented by 5 (in pounds).

[0127] Referring to FIG. 19, each of the indexing discs 233 is separated from the side plate 241 on its outer side by a distance. Each of the two ends of the axle tube 231, which passes through the two indexing discs 233, has a sleeve 254 mounted around it. The outer end of each sleeve 254 is in contact with or very close to the inner side of the corresponding side plate 241, and inner end is in contact with or very close to the outer side of the corresponding indexing disc 233. Therefore, the handle 230 and the two indexing discs 233, which are mounted around the axle tube 231, are incapable of being moved axially, but their rotation is not hindered.

[0128] Referring to FIGS. 18A-18B, FIG. 22 and FIG. 23, the two guide tubes 260 of the handle assembly 202 each accommodates an extension member 265A, 265B. Each extension member 265A, 265B is substantially a straight rod extending along the longitudinal direction, and its cross section is substantially square and the size corresponds to the opening of the guide tube 260. Each extension member 265A, 265B is movable relative to the respective guide tube 260 along the longitudinal direction, including displacement in an outward direction to (at least partially) extend out of the respective guide tube 260, and displacement in an inward direction to (at least partially) retract into the respective guide tube 260. In the present embodiment, when each extension member 265A, 265B is located at an innermost position (e.g., a preset innermost position) (as shown in FIGS. 18A-18B), it will be completely received in the corresponding guide tube 260. Furthermore, the two extension members 265A, 265B received within the two guide tubes 260 are respectively against different sides in the longitudinal direction. Specifically, the outer end of each extension member 265A, 265B is appropriately close to the through hole 247 of the outer shell 244, where the corresponding guide tube 260 is connected, at a predetermined distance, so that each extension member 265A, 265B can pass through the corresponding through hole 247 to exit the respective end seat 240A, 240B. When the extension members 265A, 265B are located at an outermost position (e.g., a preset outermost position) (as shown in FIG. 17), the inner ends of the extension members 265A, 265B are partially supported by the respective guide tubes 260. In other embodiments, the extension members 265A, 265B may not be supported by the guide tubes 260 when in the outermost positions, but may be supported by the corresponding end seat or other components. Each of the guide tubes 260 may be equivalent to an enclosure, which is located outside the handle 230 and separated by a sufficient distance that does not hinder the user from gripping the handle 230.

[0129] For the convenience of the following explanation, the two ends of the handle 230 may be referred to as the first end and the second end, respectively. Correspondingly, the end seat connected to the first end of the handle 230 is referred to as the first end seat 240A, and the end seat connected to the second end of the handle 230 is referred to as the second end seat 240B. In addition, the extension member that can pass through the through hole 247 of the first end seat 240A to the outside is referred to as the first extension member 265A, and the extension member that can pass through the through hole 247 of the second end seat 240B to the outside is referred to as the second extension member 265B. It should be noted that, just like the first and second weight plates 220A, 220B and the first and second auxiliary weight plates 225A, 225B mentioned above, the addition of “first” or “second” at the beginning of the name (and the addition of “A” or “B” at the end of the symbol) only indicates that they are located on different sides, and there is no substantial difference in their structure. In fact, based on the symmetrical structure of the handle assembly 202, when the adjustable dumbbell system 200 is used, it is not limited to a specific end of the handle assembly 202 corresponding to a specific end of the base 210. In short, the handle assembly 202 that is removed from the base 210 as shown in FIG. 16 can be put back in the same way when it is horizontally rotated 180 degrees.

[0130] By means of a linkage mechanism, the first extension member 265A and the second extension member 265B are linked to each other, so that the first extension member 265A and the second extension member 265B can be operated to move in opposite directions in the longitudinal direction. In other words, the symmetrically arranged first extension member 265A and the second extension member 265B could be moved simultaneously in either the outward or inward direction. Referring to FIG. 18B, FIG. 22 and FIG. 23, in order to constitute the linkage mechanism, the first end seat 240A is provided with a first transmission mechanism 270A (e.g., a gear transmission mechanism) that is operatively connected to the first extension member 265A, which can convert a rotational movement into a linear movement of the first extension member 265A in the longitudinal direction. Symmetrically, the second end seat 240B is provided with a second transmission mechanism 270B that is operatively connected to the second extension member 265B, which can convert a rotational movement into a linear movement of the second extension member 265B in the longitudinal direction. The rotational movement of the first transmission mechanism 270A is linked to the rotational movement of the second transmission mechanism 270B. Thus, the first extension member 265A can be interconnected with the second extension member 265B via rotational transmission means.

[0131] The first extension member 265A may be provided with a first rack 266A extending in the longitudinal direction, and the first transmission mechanism 270A may have at least one rotatable first gear, and one first gear is engaged with the first rack 266A, so that rotation of the first gear drives the first extension member 265A to move linearly. Similarly, the second extension member 265B may be provided with a second rack 266B extending in the longitudinal direction, and the second transmission mechanism 270B may have at least one rotatable second gear, and one second gear is engaged with the second rack 266B, so that rotation of the second gear drives the second extension member 265B to move linearly. Furthermore, considering that the two transmission mechanisms 270A, 270B are located at opposite ends of the handle 230 and spaced in a distance, in order to link the gear rotation movements of the first transmission mechanism 270A and the second transmission mechanism 270B, one of the first gears of the first transmission mechanism 270A and one of the second gears of the second transmission mechanism 270B may be coaxially connected, with their axes corresponding to the longitudinal direction and passing through the inside of the handle 230.

[0132] In the present embodiment, the outer side surface of each indexing disc 233 has an integrated or fixed a ring gear 271 (a bevel gear) surrounding the axle tube 231, and a pinion gear 272 (a bevel gear as well) is arranged at one specific side edge of the ring gear 271 to mesh with it, in such a manner that the axis of the pinion gear 272 is perpendicular to the axis of the ring gear 271. In this embodiment, the axis (hereinafter referred to as driven axis) A2 of the pinion gear 272 corresponds to the width direction. Each pinion gear 272 is pivotally mounted on a seat block 255 on the inner side surface of the respective side plate 241 in a manner that can rotate in place, and is coaxially fixed with a spur gear 273. Each spur gear 273 meshes with the rack 266A, 266B of the corresponding extension member 265A, 265B through the aperture 262 of the corresponding guide tube 260. Thus, when the handle 230 and the two indexing discs 233 rotate about the rotation axis A1, the two ring gears 271 will drive the respective pinion gears 272 and the spur gears 273 to rotate about the respective driven axes A2, thereby driving the first extension member 265A and the second extension member 265B to move along the longitudinal direction respectively.

[0133] As shown in FIGS. 18A-18B, the two pinion gears 272 that mesh with the respective ring gears 271 are arranged on the same side, so that no matter what rotation direction of the two ring gears 271 that are rotated synchronously, the rotation directions of the two pinion gears 272 with parallel axes are always opposite. Thus, when the handle 230 and the two indexing discs 233 rotate in a forward rotation direction F shown in FIG. 22 and FIG. 23, the first extension member 265A and the second extension member 265B will move outward simultaneously. In contrast, when the handle 230 and the two indexing discs 233 rotate in a reverse rotation direction (opposite to the forward rotation direction F), the first extension member 265A and the second extension member 265B will move inward simultaneously. That is, the two extension members 265A, 265B move in opposite directions in the longitudinal direction.

[0134] In accordance with one gear ratio, each ring gear 271 can rotate less than one circle (e.g., 330 degrees) to drive the respective extension member 265A, 265B from the innermost position to the outermost position or from the outermost position to the innermost position. When the spur gear 273 is operated to drive the rack 266A, 266B outward to the end where the spur gear 273 is stuck on a terminal end near the inner end of the rack 266A, 266B, the extension member 265A, 265B is located at the outermost position accordingly, and the handle 230 can no longer be rotated in the forward rotation direction. In contrast, when the spur gear 273 is operated to drive the rack 266A, 266B inward to the end where the spur gear 273 is stuck on a terminal end near the outer end of the rack 266A, 266B, the extension member 265A, 265B is located at the innermost position accordingly, and the handle 230 can no longer be rotated in the reverse rotation direction. Based on the symmetrical structure of the handle assembly 202, the first extension member 265A and the second extension member 265B will be located at their respective innermost positions and the outermost positions at the same time. Moreover, since the rates of the linear displacement of the two extension members 265A, 265B are identical, the protruding lengths out of the respective end seats 240A, 240B will also be identical.

[0135] In the above structures, the ring gear 271, the pinion gear 272 and the spur gear 273 disposed inside the first end seat 240A can be referred to as the first gear of the first transmission mechanism 270A. The ring gear 271, the pinion gear 272 and the spur gear 273 disposed inside the second end seat 240B can be referred to as the second gear of the second transmission mechanism 270B. The two ring gears 271 are arranged at the first end and the second end of the handle 230 respectively. The two ring gears 271 are coaxially connected, with their axes (which overlap the rotation axis A1) corresponding to the longitudinal direction and passing through the inside of the handle 230. Rotation of the handle 230 can drive the two ring gears 271 to rotate synchronously. In other embodiments, the first transmission mechanism has only one first gear, and the second transmission mechanism has only one second gear. The first gear and the second gear are coaxially connected and mesh with the first rack of the first extension member and the second rack of the second extension member respectively (for example, each gear may be a worm gear with a large diameter), which can also convert rotation movement into linear movement. Of course, the present invention can also adopt various transmission mechanisms that can convert rotation movement into linear movement.

[0136] In the present embodiment, through the selection of components and size settings in the design, the weight of the handle assembly 202 is about 5 pounds, including the handle 230, end seats 240A, 240B, guide tubes 260, extension members 265A, 265B, transmission mechanisms 270A, 270B, etc., and the total weight of several internal components not mentioned above.

[0137] Referring to FIG. 11 to FIG. 13, in the standby state, the handle assembly 202 is aligned centrally between the two ends of the base 210 in the longitudinal direction. Specifically, the handle assembly 202 is positioned between the first weight plates 220A and the second weight plates 220B. The first end and the second end of the handle 230 correspond to the directions of the first weight plates 220A and the second weight plates 220B, respectively. The outer side surfaces of the first end seat 240A and the second end seat 240B are respectively abutted against the inner side surfaces of the innermost first weight plate 220A and the innermost second weight plate 220B. In the standby state, the weight plates, the auxiliary weight plate and the end seat of the handle assembly located on any half of the base 210 can be called the first weight plates, the first auxiliary weight plate and the first end seat, respectively, and the weight plates, the auxiliary weight plate and the end seat of the handle assembly located on the other half of the base 210 can be called the second weight plates, the second auxiliary weight plate and the second end seat, respectively. The grooves 248 on the outer side surfaces of the first end seat 240A and the second end seat 240B are respectively engaged with the aforementioned ridges 222 on the inner side surfaces of the first weight plate 220A and the second weight plate 220B (see FIGS. 18A-18B). When the weight plates 220A, 220B are correctly attached to the respective end seats 240A, 240B, the through hole 247 on the outer side of the first end seat 240A will be aligned with the recess 223 of the first weight plate 220A, so that the movement path (extension axis) of the first extension member 265A is aligned with the first channel 224A. Symmetrically, the through hole 247 on the outer side of the second end seat 240B may be aligned with the recess 223 of the second weight plate 220B, so that the movement path of the second extension member 265B is aligned with the second channel 224B. At the same time, as shown in FIGS. 18 and 19, the first auxiliary weight plate 225A and the second auxiliary weight plate 225B, whose bottoms are respectively inserted into the two positioning recesses 214 of the base 210, and at least their upper halves are respectively located in the chambers 249 of the first end seat 240A and the second end seat 240B, and are respectively located on the inner sides of the respective indexing discs 233, with the upward U-shaped openings 227 accommodating the corresponding ends of the handle 230. The two opposite sides of each auxiliary weight plate 255A, 255B in the width direction can be embedded in the two opposite guiding members 261 in the corresponding chamber 249.

[0138] As shown in FIG. 16, the handle assembly 202 can be moved upward along the extension direction of the grooves 248 and the guiding members 261 to leave the base 210 alone. Similarly, the handle assembly 202 that leaves the base 210 can have its grooves 248 on the two ends align and move downward to engage the ridges 222 of the innermost two weight plates 220A, 220B (at the same time, the guiding members 261 will accommodate the two sides of the two auxiliary weight plates 225A, 225B) to return to the preset position in the standby state. During this process, the first auxiliary weight plate 225A and the second auxiliary weight plate 225B respectively enter or exit the chambers 249 of the first and second end seats 240A, 240B through the large openings 252 (see FIG. 15) at the bottoms of the first and second end seats 240A, 240B.

[0139] FIG. 24A is a cross-sectional view of the first end seat 240A, with the internal conformation of the second end seat 240B being the same. As shown in FIG. 24A, in the standby state, when the first and second extension members 265A, 265B are in the innermost positions, the twelve positioning holes 237 on each indexing disc 233 will be located at twelve positions (centered on the aforementioned rotation axis A1) of one o'clock, two o'clock, three o'clock, . . . , and twelve o'clock, and one specific positioning hole 237 is located directly below the rotation axis A1 (six o'clock position), and the six convex lumps 235 on each indexing disc 233 are located at one o'clock, three o'clock, five o'clock, seven o'clock, nine o'clock and eleven o'clock, respectively, avoiding the position directly below the rotation axis A1. At this time, the weight indicator 239 located at the top (12 o'clock position) on the circumference of each indexing disc 233 indicates the minimum value of “5”. The user can see the weight indicator 239 located at the top of the indexing disc 233 through the window 251 on the top of the first end seat 240A and the second end seat 240B. When the user rotates the handle 230 and the two indexing discs 233 in the forward rotation direction from the current angular position (hereinafter referred to as the starting angular position), the weight indicators 239 on the circumference of each indexing disc 233 will pass under the window 251 in the order of “10”, “15”, “20”, etc. In this embodiment, each time the handle 230 is rotated 30 degrees (as a unit angle), the indexing disc 233 rotates 30 degrees accordingly so that the next weight indicator 239 in accordance with the rotation direction is positioned on the top, and the positioning hole 237 is changed to the next, for example, changed from the state shown in FIG. 24A to the state shown in FIG. 24B (Note: the positions of the convex lumps 235 in the two figures differ by 30 degrees), or vice versa. On the other hand, when the handle 230 rotates one unit angle, both the first extension member 265A and the second extension member 265B will move a unit distance along the longitudinal direction, respectively. The unit distance is approximately equal to half the thickness of each weight plate 220A, 220B in the longitudinal direction, that is, half the length of the recess 223 that passes through the inner and outer sides of the weight plate in the longitudinal direction.

[0140] When the first extension member 265A and the second extension member 265B are located at the innermost position, the distance between the outer end face of each extension member 265A, 265B and the outer side surface of the corresponding end seat 240A, 240B is slightly greater than the unit distance. After the handle 230 is rotated by one unit angle (30 degrees) in the forward rotation direction from the starting angular position, the angle of each indexing disc 233 relative to the end seat 240A, 240B is shown in FIG. 24B. At this time, the weight indicator 239 positioned on the top indicates a value of “10”, and the outer end face of each extension member 265A, 265B is close to the outer side surface of the corresponding end seat 240A, 240B. If the handle 230 is rotated by another unit angle in the forward rotation direction (equal to 60 degrees of cumulative forward rotation), the angle of each indexing disc 233 relative to the end seat 240A, 240B will be similar to the state shown in FIG. 24A. At this time, the weight indicator 239 on the top indicates a value of “15”, and the outer end of each extension member 265A, 265B is protruded from the respective end seat 240A, 240B via the corresponding through hole 247, and extended into the recess 223 of the innermost first weight plate 240A or the innermost second weight plate 240B, with the outer end face being approximately located at the middle of the recess 223. If the handle 230 is further rotated by another unit angle in the forward rotation direction (equal to 90 degrees of cumulative forward rotation), the angle of each indexing disc 233 relative to the end seat 240A, 240B will be similar to the state shown in FIG. 24B again. At this time, the weight indicator 239 on the top indicates a value of “20”, and the outer end face of each extension member 265A, 265B is close to the outer side surface of the innermost first weight plate 220A or the innermost second weight plate 220B. The rest can be deduced by analogy. Finally, if the handle 230 is rotated 330 degrees in the forward rotation direction from the starting angular position (i.e., 11 times the unit angle), the angle of each indexing disc 233 relative to the end seat 240A, 240B will be similar to the state shown in FIG. 24B. At this time, the weight indicator 239 positioned on the top is marked as the maximum value “60”, and the outer end face of each extension member 265A, 265B is close to the outer side surface of the outermost first weight plate 220A or the outermost of the second weight plate 220B, reaching the outermost position of the preset movement range.

[0141] In summary, when the handle 230 is at the starting angular position, or the angular position differs from the starting angular position by an even multiple of the unit angle (equal to a cumulative forward rotation of 60, 120, 180, 240 or 300 degrees), the angle of each indexing disc 233 relative to the end seat 240A, 240B is shown as FIG. 24A. Besides, the convex lumps 235 of each indexing disc 233 avoid the position directly under the lock portion 226 of the auxiliary weight plate 225A, 225B. When the angular position of the handle 230 differs from the starting angular position by an odd multiple of the unit angle (equal to a cumulative forward rotation of 30, 90, 150, 210, 270 or 330 degrees), the angle of each indexing disc 233 relative to the end seat 240A, 240B is shown as FIG. 24B. Besides, one of the convex lumps 235 of each indexing disc 233 is blocked directly under the lock portion 226 of the corresponding auxiliary weight plate 225A, 225B, and the top surface of the convex lump 235 is abutted against the bottom surface of the lock portion 226.

[0142] In general, in the standby state, the handle 230 of the handle assembly 202 (together with the indexing discs 233 and the ring gears 271) can rotate forwardly or reversely within a preset angle range (e.g., 330 degrees) relative to the end seats 240A, 240B that are anchored on the base 210. Each time the handle 230 is rotated in the forward rotation direction by a predetermined angle (e.g., the aforementioned unit angle), the first extension member 265A can be moved in the direction away from the second end seat 240B by a predetermined distance (e.g., the aforementioned unit distance), and the second extension member 265B can be moved in the direction away from the first end seat 240A by the predetermined distance simultaneously. In contrast, each time the handle 230 is rotated in the reverse rotation direction by the predetermined angle, the first extension member 265A can be driven to move in the direction close to the second end seat 240B by the predetermined distance, and the second extension member 265B can be moved in the direction close to the first end seat 240A by the predetermined distance simultaneously. In the present embodiment, the handle 230 and the indexing discs 233 can be positioned at one of twelve predetermined angular positions (including the starting angular position) relative to the end seats 240A, 240B. That is, when one of the positioning holes 237 of the indexing disc 233 is directly below the rotation axis A1, the handle 230 and the indexing disc 233 are positioned at one of the predetermined angular positions. Any two adjacent predetermined angular positions are 30 degrees apart.

[0143] Referring to FIG. 25A, a steel ball 280 is disposed in each end seat 240A, 240B, on the outer side of the corresponding indexing disc 233. The steel ball 280 is elastically biased by a spring in an inward direction. When the indexing disc 233 is located at any predetermined angular position, the inner half of the steel ball 280 will sink into a corresponding one of the predetermined ball socket 238 on the respective indexing disc 233 (in this embodiment, the ball socket 238 is located directly below the rotation axis A1). During the indexing disc 233 rotating from one of the predetermined angular positions to the next one, as shown in FIG. 25B, the steel ball 280 will be squeezed out of the ball socket 238 and abut against the flat part of the outer side surface of the indexing disc 233 until it “clicks” and sinks into the next ball socket 238. In this way, when the user rotates the handle 230, there will be a pause or calibration effect at the predetermined angular positions, creating the sensation of stepwise adjustment.

[0144] As shown in FIGS. 25A and 25B, when the handle assembly 202 is placed on the base 210, the two hooks 216 of the base 210 respectively extend into the interiors of the end seats from the small openings 253 (see FIG. 15) at the bottoms of the two end seats 240A, 240B, such that each hook 216 is located at the bottom of the outer side of the respective indexing disc 233, and the horizontal extension part of the top of each hook 216 that bends inward is slightly higher than the bottom edge of the circumference of the respective indexing disc 233. As shown in FIGS. 24A and 24B, when the indexing disc 233 is at any predetermined angular position, the hook 216 is between the two adjacent teeth 236 at the bottom of the circumference of the indexing disc 233 (e.g., located at 5:30 and 6:30 positions). Therefore, as long as the handle 230 is at one of the twelve predetermined angular positions, the handle assembly 202 can be smoothly lifted up from the base 210 and put back onto the base 210 without interference from the hook 216. However, if the handle 230 is not in any predetermined angular position (for example, the indexing disc 233 is rotated 15 degrees clockwise or counterclockwise from the angle shown in FIG. 24A or FIG. 24B), one of the teeth 236 (all or part) at the bottom of each indexing disc 233 will be located below the horizontal extension part of the corresponding hook 216, so that the handle assembly 202 cannot be lifted up from the base 210.

[0145] Referring to FIG. 25A, inside each end seat 240A, 240B, there is a locking member 290 that can slide slightly along the longitudinal direction and a releasing member 295 that can slide slightly along the height direction, at the bottom of the outer side of the respective indexing disc 233. The releasing member 295 is located below the locking member 290 and is close to the small opening 253 at the bottom of the end seat 240A, 240B. The locking member 290 is elastically biased by a compression spring 291 in an inward direction. The locking member 290 and the releasing member 295 are abutted against each other by their incline planes, such that movement of the locking member 290 in the inward direction pushes the releasing member 295 to move downward, while upward movement of the releasing member 295 pushes the locking member 290 to move in the outward direction. The locking member 290 has a latch 292 extending in the longitudinal direction on its inner side. When the indexing disc 233 is located at any predetermined angular position, the latch 292 of the locking member 290 is substantially coaxial with the positioning hole 237 of the indexing disc 233 located below the rotation axis A1. When the handle assembly 20 is rested on the base 210, the two bumps 215 of the base 210 will enter the interiors of the end seats 240A, 240B through the small openings 253 at the bottoms of the two end seats 240A, 240B respectively, so that each releasing member 295 will be pushed upward by the corresponding bump 215 to a higher position as shown in FIG. 25A. In addition, each locking member 290 is pushed to a relatively outer position within its movable range by the corresponding releasing member 295 (compressing the compression spring 291), so that the latch 292 is pulled out of the positioning hole 237 of the respective indexing disc 233 and does not hinder the rotation of the indexing disc 233 and the handle 230. When the handle assembly 202 is moved upward from the base 210, the bumps 215 will be relatively downward, and each locking member 290 (which is pushed or biased by the compression spring 291) will immediately push the corresponding releasing member 295 downward to a lower position as shown in FIG. 28. In addition, each locking member 290 will move to a relatively inner position within its movable range, so that the latch 292 is inserted in the specific positioning hole 237 of the respective indexing disc 233. Therefore, the indexing discs 233 and the handle 230 can be locked at the current angular position.

[0146] In summary, the hooks 216 and the bumps 215 on the base 210, and the teeth 236 and the positioning holes 237 on each indexing disc 233, and locking member 290, the releasing member 295 and the compression spring 291 of each end seat 240A, 240B, and so on, together constitute a locking mechanism with dual functions. In short, when the handle assembly 202 is placed on the base 210, the handle 230 is allowed to rotate freely within a preset angle range (so that the angle of the two indexing discs 233 and the positions of the two extension members 265A, 265B can be changed accordingly), but the handle assembly 202 can only leave the base 210 when the handle 230 is located in the predetermined angular position. As soon as the handle assembly 202 leaves or disengages the base 210, the handle 230 will be locked in the current angular position, preventing the angle of the two indexing discs 233 and the positions of the two extension members 265A, 265B from being changed until the handle assembly 202 is placed back into the base 210 again.

[0147] With the adjustable dumbbell system 200 provided in this embodiment, the user can rotate the handle 230 to selectively engage the first and second weight plates 220A, 220B and / or the first and second auxiliary weight plates 225A, 225B on the handle assembly 202 so as to select or adjust the dumbbell weight for weight training. The working principle of selectively engaging of the weight plates 220A, 220B is basically the same as that of the previous embodiment. That is, rotating the handle 230 will drive the first and second extension members 265A, 265B to move simultaneously in the outward or inward direction via the aforementioned first and second transmission mechanism 270A, 270B. Specifically, the first extension member 265A can extend from the corresponding guide tube 260 and the first end seat 240A in the direction away from the second end seat 240B, and extend outward into the recesses 223 of the first weight plates 220A in sequence to engage one or more first weight plates 220A. In contrast, the second extension member 265B can extend from the corresponding guide tube 260 and the second end seat 240B in the direction away from the first end seat 240A, and extend outward into the recesses 223 of the second weight plates 220B in sequence to engage one or more second weight plates 220B. For example, as shown in FIG. 26, in the state that the outer ends of the first extension member 265A and the second extension member 265B respectively extended into the recesses 223 of the second one of the first weight plates 220A and the second one of the second weight plates 220B (counted from inside to outside), when the user grasps the handle assembly 202 and moves it upward away from the base 210, the first extension member 265A and the second extension member 265B will hold up the inner two first weight plates 220A and the inner two second weight plates 220B respectively (the remaining weight plates 220A, 220B remain on the base 210). Moreover, since the possible displacement direction (i.e., displacement from top to bottom) of each weight plate 220A, 220B relative to the other weight plate 220A, 220B or the handle assembly 202 on its inner side is blocked by the extension member 265A, 265B, such that the lifted weight plates 220A, 220B can remain in place at both ends of the handle assembly 202 without falling off. In the present embodiment, when each extension member 265A, 265B is operated to move outward to engage one more weight plate 220A, 220B, the weight of the dumbbell 204 will increase by 10 pounds (that is, the weight of a pair of weight plates 265A and 265).

[0148] As mentioned above, in the present embodiment, the handle 230 is rotated and positioned stepwise at a unit angle of 30 degrees. Correspondingly, the extension members 265A, 265B extend or retract stepwise or steplessly with half the thickness of each weight plate 220A, 220B as a unit distance. Therefore, as the handle 230 is positioned at different predetermined angular positions, the outer end of each extension member 265A, 265B may sometimes extend close to the outer end of the recess 223, or sometimes only extend to the middle of the recess 223. However, based on the appropriate size setting, even if the extension members 265A, 265B are only extended into half the thickness of a certain weight plate 220A, 220B (even slightly less), the weight plates 220A, 220B can be lifted upward and can be blocked from detaching in the height direction. For example, as shown in FIG. 29, when the outer ends of the first extension member 265A and the second extension member 265B are respectively located in the middle positions of the recesses 223 of the third one of the first weight plates 220A and the third one of the second weight plates 220B (counted from inside to outside), the handle assembly 202 detached from the base 210 will engage three pairs of weight plates 220A, 220B. Comparing FIG. 26 and FIG. 29, the extension members 265A, 265B can be operated to move outward by one unit distance from the position shown in FIG. 26 to the position shown in FIG. 29, so that the weight plates 220A, 220B held up by the extension members 265A, 265B can be increased from two pairs to three pairs. However, the extension members 265A, 265B can still only hold the same three pairs of weight plates 220A, 220B when they are operated to move outward by a further one unit distance (in the standby state). In summary, when the handle 230 is rotated from one predetermined angular position to another predetermined angular position in the forward rotation direction by the unit angle twice (i.e., 60 degrees), an additional first weight plate 220A and second weight plate 220B will be added to the handle assembly 202. When the handle 230 is rotated from one predetermined angular position to another predetermined angular position in the reverse rotation direction by the unit angle twice, the handle assembly 202 will disengage one first weight plate 220A and one second weight plate 220B.

[0149] On the other hand, as mentioned above, when the handle 230 is located in the first, third, fifth, . . . , or eleventh predetermined angular position of the twelve predetermined angular positions (starting from the starting angular position), the angle of each indexing disc 233 is shown as FIG. 24A, and the convex lumps 235 of each indexing disc 233 avoid the position directly below the lock portion 226 of the auxiliary weight plate 225A, 225B. When the handle 230 is located in the second, fourth, sixth, . . . , or twelfth predetermined angular positions, the angle of each indexing disc 233 is shown as FIG. 24B, and one of the convex lumps 235 of each indexing disc 233 is blocked directly under the lock portion 226 of the corresponding auxiliary weight plate 225A, 225B. In the state shown in FIG. 24A, the handle assembly 202 does not hook the two auxiliary weight plates 225A, 225B when it moves upward away from the base 210. Therefore, after the handle assembly 202 leaves or disengages the base 210, the auxiliary weight plates 225A, 225B are still in their preset positions on the base 210. In the state shown in FIG. 24B, when the handle assembly 202 is lifted upwardly from the base 210, since each indexing disc 233 has one convex lump 235 blocked directly under the lock portion 226 of the corresponding auxiliary weight plate 225A, 225B, the two auxiliary weight plates 225A, 225B will be lifted upward respectively (see FIG. 27 and FIG. 28). Moreover, since the auxiliary weight plates 225A, 225B cannot move downward or in other directions with respect to the handle assembly 202 at this time (the upward movement is blocked by the handle 230, and the movements in the width and longitudinal directions are retained by the guiding members 261), the two auxiliary weight plates 225A, 225B that are lifted can be kept engaged at the two ends of the handle assembly 202 (inside the first and second end seats 240A, 240B) without falling off. Thus, when the handle 230 is rotated from one predetermined angular position to another predetermined angular position by one unit angle, the handle assembly 202 can be changed from the state with the two auxiliary weight plates 225A, 225B to the state without the two auxiliary weight plates 225A, 225B, or vice versa. In this embodiment, mounting the two auxiliary weight plates 225A, 225B increases the weight of the dumbbell 204 by 5 pounds.

[0150] Referring to the auxiliary weight plates 220A, 220B mentioned above, in the standby state, the user is able to read the weight indicator 239 through the window 251 on the top of each end seat 240A, 240B of the handle assembly 202 to know the current weight of the dumbbell. For example, if the value below the window 251 is “5”, it means that the handle assembly 202 is not engaged with any weight plate 220A, 220B or auxiliary weight plate 225A, 225B. As shown in FIG. 16, the user can individually grasp the handle assembly 202 from the base 210 and perform weight training with only the 5-pound handle assembly 202 (i.e., the lightest dumbbell 204). If the user wants to change the weight of the dumbbell 204, the handle 230 can be rotated to an appropriate predetermined angular position in the standby state, namely rotating the handle 230 to change the value below the window 251 to the target weight, so that the handle assembly 202 can be mounted with an appropriate number of weight plates 220A, 220B and / or auxiliary weight plates 225A, 225B to from a dumbbell 204 with the target weight. For example, if the handle 230 is rotated from the aforementioned starting angular position (corresponding to the lightest dumbbell) by one unit angle in the forward rotation direction to the second predetermined angular position, the handle assembly 202 will engage the two auxiliary weight plates 225A, 225B, and the value below the window 251 will become “10”, which is equal to the sum of weights of the handle assembly 202 and the two auxiliary weight plates 225A, 225B. If the handle 230 is rotated to the third predetermined angular position, the handle assembly 202 will disengage the two auxiliary weight plates 225A, 225B, and the innermost pair of weight plates 220A, 220B will be mounted, and the value below the window 251 will become “15”, which is equal to the sum of the weights of the handle assembly 202 and a pair of weight plates 220A, 220B. If the handle 230 is rotated to the fourth predetermined angular position, the handle assembly 202 will engage the innermost pair of the weight plates 220A, 220B and the two auxiliary weight plates 225A, 225B simultaneously, and the value below the window 251 will become “20”, which is equal to the sum of the weights of the handle assembly 202, a pair of weight plates 220A, 220B and the two auxiliary weight plates 225A, 225B. The rest can be deduced accordingly. Finally, if the handle 230 is rotated to the twelfth predetermined angular position, the handle assembly 202 will engage all the weight plates 220A, 220B and the two auxiliary weight plates 225A, 225B simultaneously, and the value below the window 251 will become “60”, which is equal to the sum of the weights of the handle assembly 202, five pairs of weight plates 220A, 220B and the two auxiliary weight plates 225A, 225B, forming the heaviest dumbbell 204 in the adjustable range, as shown in FIG. 17.

[0151] In short, the adjustable dumbbell system 200 provided in the present embodiment allows the user to select or adjust the most suitable dumbbell weight from the twelve weight options, which range from the lightest 5 pounds to the heaviest 60 pounds in 5-pound increments according to the personal physical ability and weight training content.

[0152] In this manner, the handle 230 in the handle assembly 202 forms a weight selection portion that can be rotated by the user to select or adjust the weight of the dumbbell. However, the weight selection portion is not limited to the entire handle. For example, in other embodiments, a portion of the handle can form the weight selection portion such as an annular component located at one or both ends of the outer side of the grip portion, or a knob or dial can be provided on at least one of the end seats of the handle assembly as the weight selection portion. The rotation axis of the weight selection portion may be coaxial, parallel or non-parallel (e.g., perpendicular) to the rotation axis A1 of the two indexing discs 233 or the two ring gears 271, and a rotation transmission mechanism for changing the rotational speed and / or direction may be mounted between the weight selection portion and the indexing discs or the ring gears. In summary, in various preferred embodiments, each time the weight selection portion is rotated in a forward rotation direction by a predetermined angle (e.g., the aforementioned unit angle), the first extension member 265A can be driven to move a predetermined distance (e.g., the aforementioned unit distance) in a direction away from the second end seat 240B, while the second extension member 265B can be driven to move the predetermined distance in a direction away from the first end seat 240A at the same time. In contrast, each time the weight selection portion is rotated in a reverse direction by the predetermined angle, the first extension member 265A can be driven to move the predetermined distance in a direction close to the second end seat 240B, while the second extension member 265B can be driven to move the predetermined distance in the direction close to the first end seat 240A at the same time.

[0153] In addition, the indexing disc 233 in the first end seat 240A forms a first engaging member, and the indexing disc 233 in the second end seat 240B forms a second engaging member. The first engaging member and the second engaging member can be driven by rotation of the weight selection portion. When the weight selection portion is located at specific predetermined angular positions (e.g., the state shown in FIG. 24A, the convex lumps 235 avoid the position directly under the lock portion 226), the first engaging member and the second engaging member do not engage the first auxiliary weight plate 225A and the second auxiliary weight plate 225B. When the weight selection portion is located at other predetermined angular positions (e.g., the state shown in FIG. 24A, one of the convex lumps 235 is located directly under the lock portion 226), the first engaging member and the second engaging member respectively engage the first auxiliary weight plate 225A and the second auxiliary weight plate 225B, so that the handle assembly 202 can be operated to selective engage the first auxiliary weight plate 225A and the second auxiliary weight plate 225B.

[0154] Under this arrangement, the adjustable dumbbell system 200 allows the user to perform weight selection in a simple, quick and reliable manner, so as to obtain a dumbbell with the desired weight and identical weights on both ends. Furthermore, in accordance with the second embodiment, the adjustable dumbbell system 200 allows the user to make fine adjustments to the weight of the dumbbell, so as to better suit their personal conditions and actual needs. In addition, the adjustable dumbbell system can use fewer weight components under the same maximum total weight level, providing more adjustment levels and a smaller adjustment range.

[0155] FIG. 30 shows an adjustable dumbbell system 300 in accordance with a third embodiment of the present invention. Similar to the previous embodiment, the adjustable dumbbell system 300 includes a base 310, a plurality of first weight plates 320A, a plurality of second weight plates 320B, a first auxiliary weight plate and a second auxiliary weight plate (hidden in the figure), and a handle assembly 302. FIG. 30 depicts that the handle assembly 302 mounting all weight plates 320A, 320B and auxiliary weight plates, forming the heaviest dumbbell 304.

[0156] The handle assembly 302 also includes a handle 330, a first end seat 340A and a second end seat 340B respectively connected to the two opposite ends of the handle 330, and two guide tubes 360 connected to the two end seats 340A, 340B along the longitudinal direction, and a first extension member 365A and a second extension member 365B respectively (at least partially) accommodated in the two guide tubes 360. Referring to FIG. 31, the operation principle is the same as that of the precious embodiment. Rotating the handle 330 will drive a ring gear 371 inside each end seat 340A, 340B to rotate synchronously, causing a pinion gear 372 that is engaged with the ring gear 371 to rotate at a faster speed. Each pinion gear 372 is coaxially fixed to a spur gear 373. Each spur gear 373 meshes with a first rack 366A of the first extension member 365A or a second rack of the second extension member 365B. Thus, forward rotation of the handle 330 will drive the first extension member 365A and the second extension member 365B to extend outward, and reverse rotation of the handle 330 will drive the first extension member 365A and the second extension member 365B to retract inward. In the present embodiment, the cross section of each extension member 365A, 365B is approximately a rectangle, and the cross-sectional shape of the recess 323 in each weight plate 320A, 320B (for receiving the extension member) corresponds to it. In addition, the recess 323 is a through hole that passes through the weight plate 320A, 320B, not touching the outer edge of the weight plate 320A, 320B.

[0157] The third embodiment is similar to the second embodiment, except the locking mechanism for locking the handle 330 (or weight selection portion) and the two extension members 365A, 365B. Referring to FIG. 31 and FIG. 32A, in this embodiment, the portions of the base 310 corresponding to the first end seat 340A and the second end seat 340B, each is provided with a bump 315 and a vertical piece 318. The vertical piece 318 has a slot 319. Each extension member 365A, 365B has a plurality of positioning holes 367 spaced equidistantly along the longitudinal direction, and a plurality of ball sockets 368 spaced equidistantly along the longitudinal direction. The number of the positioning holes 367 is the same as the number of the predetermined angular positions of the weight selection portion, such as twelve. As shown in FIG. 32A, inside each end seat 340A, 340B, there is a locking member 390 that can slide slightly in the width direction, and a releasing member 395 that can slide slightly in the height direction. The locking member 390 and the releasing member 395 are abutted against each other by their incline planes, so that if the locking member 390 moves in the outward direction (referring to the direction toward the corresponding extension member 365A, 365B, such as left direction in FIG. 32A), it will push the releasing member 395 downward, and if the releasing member 395 moves upward, it will push the locking member 390 to move in the inward direction (as the right direction in FIG. 32A). The locking member 390 has a latch 392 extending in the width direction, which is elastically biased by a compression spring 391 in the outward direction. When the handle 330 is located at any predetermined angular position, the latch 392 of each locking member 390 is substantially coaxial with one positioning hole 367 on the corresponding extension member 365A, 365B.

[0158] As shown in FIG. 32A, when the handle assembly 302 is placed on the base 310, the two bumps 315 will enter the interiors of the end seats 340A, 340B through the openings 353 at the bottoms of the two end seats 340A, 340B respectively, so that each releasing member 395 will be pushed upward by the corresponding bump 315 to a higher position, and each locking member 390 will be pushed to a relatively inner position within its movable range by the corresponding releasing member 395 (compressing the compression spring 391), so that the latch 392 is pulled out of the positioning hole 367 of the respective extension member 365A, 365B and does not hinder the rotation of the extension member 365A, 365B and the handle 330. As shown in FIG. 32B, when the handle assembly 302 is moved upward from the base 210, the bumps 315 will be relatively downward, and each locking member 390 (which is pushed or biased by the compression spring 391) will immediately push the corresponding releasing member 395 downward to a lower position, and then each locking member 390 will move to a relatively outer position within its movable range, so that the latch 392 can be inserted into a specific positioning hole 367 of the respective extension member 365A, 365B. Therefore, the two extension members 365A, 365B and the handle 330 can be locked.

[0159] Referring to FIG. 32A, when the handle assembly 302 is placed on the base 310, the two vertical pieces 318 on the base 310 respectively extend into the interiors of the two end seats 340A, 340B. At the same time, the locking member 390 pushed inward (to the right in FIG. 32A) by the releasing member 395 causes the inner end of the latch 392 to pass through the slot 319 of the corresponding vertical piece 318. If the handle 330 is not in any predetermined angular position, so that each extension member 365A, 365B has no positioning hole 367 aligned with the latch 392, then, the latch 392 cannot move outward (to the left). That is, the inner end of the latch 392 cannot be pulled out of the slot 319 of the respective vertical piece 318, such that the handle assembly 302 cannot be lifted from the base 310.

[0160] A steel ball (not shown) may be disposed at an appropriate position inside each end seat 340A, 340B. When the handle 330 is located at any predetermined angular position, the steel ball will sink into a corresponding one of the ball sockets 368.

[0161] FIG. 33 shows an adjustable dumbbell system 400 in accordance with a fourth embodiment of the present invention. Except as otherwise described below, the adjustable dumbbell system 400 may be similar to the adjustable dumbbell system 100, 200, or 300, described above. For example, the adjustable dumbbell system 400 may include any combination of features disclosed above with reference to adjustable dumbbell system 100, adjustable dumbbell system 200, or adjustable dumbbell system 300. Without intent to limit, the adjustable dumbbell system 400 may include a handle 430, two guide tubes 460, and a first extension member 465A and a second extension member 465B accommodated in the two guide tubes 460.

[0162] The adjustable dumbbell system 400 may be adjusted in a manner similar to those described above. For example, rotating the handle 430 may drive a ring gear 471 (e.g., at each end) to rotate (e.g., about the longitudinal axis of the handle 430). The ring gear 471 may be formed or coupled with the handle 430. For example, the ring gear 471 and handle 430 may be formed integrally as a single part. In other examples, the ring gear 471 may be coupled to the handle 430. In one example, the ring gear 471 may be coupled to or formed with a tube that is connected to the handle 430. Although described with reference to rotating handle 430, the adjustable dumbbell system 400 may be actuated in a different manner, such as rotating a dial on the dumbbell or the base. For sake of convenience, only one end of the adjustable dumbbell system 400 will be described with reference to FIG. 33, with the other end operated in a similar manner.

[0163] The adjustable dumbbell system 400 may include a pinion gear 472 engaged with the ring gear 471. The pinion gear 472 may mesh with the ring gear 471, such that rotation of the ring gear 471 rotates the pinion gear 472. The pinion gear 472 may be coupled to a worm gear 473, so that rotation of the pinion gear 472 rotates the worm gear 473. The pinion gear 472 and worm gear 473 may be coaxially aligned. In one example, the pinion gear 472 is fixed to the worm gear 473 to rotate the worm gear 473 directly with the pinion gear 472. In another example, a transmission may couple the pinion gear 472 to the worm gear 473 to drive the worm gear 473 at a different ratio compared to the pinion gear 472. The pinion gear 472 and worm gear 473 may rotate about an axis parallel to the longitudinal axis of the handle 430, or the pinion gear 472 and worm gear 473 may be aligned along a different axis.

[0164] The worm gear 473 meshes with the first extension member 465A. For example, the first extension member 465A may define or include a first rack 466A. Thus, forward rotation of the handle 430 will drive the first extension member 465A to extend outward, and reverse rotation of the handle 430 will drive the first extension member 465A to retract inward. A similar configuration may be provided at the opposite end of the adjustable dumbbell assembly 400 to drive the second extension member 465B with rotation of the handle 430. In this manner, the first and second extension members 465A, 465B may be driven outward or inward with rotation of the handle 430 to selectively engage a subset of weights or weight plates, such as in a manner as described above. For example, rotating the handle 430 may drive the first and second extension members 465A, 465B to move simultaneously in the outward or inward direction to engage one or more weight plates in sequence.

[0165] FIG. 34 shows an adjustable dumbbell system 500 in accordance with a fifth embodiment of the present invention. Except as otherwise described below, the adjustable dumbbell system 500 may be similar to the adjustable dumbbell system 100, 200, 300, or 400, described above. For example, the adjustable dumbbell system 500 may include any combination of features disclosed above with reference to adjustable dumbbell system 100, adjustable dumbbell system 200, adjustable dumbbell system 300, or adjustable dumbbell system 400. Without intent to limit, the adjustable dumbbell system 500 may include a handle 530, two guide tubes 560, and a first extension member 565A and a second extension member 565B accommodated in the two guide tubes 460.

[0166] Similar to the adjustable dumbbell system 400, the adjustable dumbbell system 500 may include a ring gear 571 (e.g., at each end of the handle 530). Rotating the handle 530 or another portion of the adjustable dumbbell system 500 (e.g., a dial on the dumbbell or the base) may drive a ring gear 571 to rotate (e.g., about the longitudinal axis of the handle 530). The ring gear 571 and handle 530 may be formed integrally as a single part, or the ring gear 571 may be coupled to the handle 530. Similar to adjustable dumbbell system 400, only one end of the adjustable dumbbell system 500 is described with reference to FIG. 34, for sake of convenience. It should be understood that the other end may include a similar configuration operated in a similar manner.

[0167] The ring gear 571 may define a worm gear 573. The worm gear 573 may mesh with the first extension member 565A. For example, the first extension member 565A may define or include a first rack 566A that meshes with the worm gear 573. In this manner, the handle 530 or ring gear 571 / worm gear 573 may rotate to directly actuate the first extension member 565A. Thus, forward rotation of the handle 530 will drive the first extension member 565A to extend outward, and reverse rotation of the handle 530 will drive the first extension member 565A to retract inward. A similar configuration may be provided at the opposite end of the adjustable dumbbell assembly 500 to drive the second extension member 565B with rotation of the handle 530. As a result, the first and second extension members 565A, 565B may be driven outward or inward with rotation of the handle 530 to selectively engage a subset of weights or weight plates, such as in a manner as described above. For example, rotating the handle 530 may drive the first and second extension members 565A, 565B to move simultaneously in the outward or inward direction to engage one or more weight plates in sequence.

[0168] The description of certain embodiments included herein is merely exemplary in nature and is in no way intended to limit the scope of the disclosure or its applications or uses. In the included detailed description of embodiments of the present systems and methods, reference is made to the accompanying drawings which form a part hereof, and which are shown by way of illustration specific to embodiments in which the described systems and methods may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice presently disclosed systems and methods, and it is to be understood that other embodiments may be utilized, and that structural and logical changes may be made without departing from the spirit and scope of the disclosure. Moreover, for the purpose of clarity, detailed descriptions of certain features will not be discussed when they would be apparent to those with skill in the art so as not to obscure the description of embodiments of the disclosure. The included detailed description is therefore not to be taken in a limiting sense, and the scope of the disclosure is defined only by the appended claims.

[0169] From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention.

[0170] The particulars shown herein are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present disclosure and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of various embodiments of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for the fundamental understanding of the invention, the description taken with the drawings and / or examples making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

[0171] As used herein and unless otherwise indicated, the terms “a” and “an” are taken to mean “one”, “at least one” or “one or more”. Unless otherwise required by context, singular terms used herein shall include pluralities and plural terms shall include the singular.

[0172] Unless the context clearly requires otherwise, throughout the description and the claims, the words ‘comprise’, ‘comprising’, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. Words using the singular or plural number also include the plural and singular number, respectively. Additionally, the words “herein,”“above,” and “below” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of the application.

[0173] All relative, directional, and ordinal references (including top, bottom, side, front, rear, first, second, third, and so forth) are given by way of example to aid the reader's understanding of the examples described herein. They should not be read to be requirements or limitations, particularly as to the position, orientation, or use unless specifically set forth in the claims. Connection references (e.g., attached, coupled, connected, joined, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other, unless specifically set forth in the claims.

[0174] Of course, it is to be appreciated that any one of the examples, embodiments or processes described herein may be combined with one or more other examples, embodiments and / or processes or be separated and / or performed amongst separate devices or device portions in accordance with the present systems, devices and methods.

[0175] Finally, the above discussion is intended to be merely illustrative of the present system and should not be construed as limiting the appended claims to any particular embodiment or group of embodiments. Thus, while the present system has been described in particular detail with reference to exemplary embodiments, it should also be appreciated that numerous modifications and alternative embodiments may be devised by those having ordinary skill in the art without departing from the broader and intended spirit and scope of the present system as set forth in the claims that follow. Accordingly, the specification and drawings are to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.

Examples

second embodiment

[0115]FIGS. 11, 12 and 13 are respectively a perspective view, a side view and a top view of an adjustable dumbbell system 200 (hereinafter, sometimes simply referred to as an adjustable dumbbell) in a standby state according to the present invention. With additional reference to FIG. 14 and FIG. 15, the adjustable dumbbell system 200 includes a base 210, a plurality of first weight plates 220A, a plurality of second weight plates 220B, a first auxiliary weight plate 225A, a second auxiliary weight plate 225B and a handle assembly 202, or a combination thereof, that can be separated or combined with each other. In terms of weight selection function, the user can selectively attach the first and second weight plates 220A, 220B (hereinafter, sometimes simply called weight plates) and / or the first and second auxiliary weight plates 225A, 225B (hereinafter, sometimes simply called auxiliary weight plates) to the handle assembly 202 according to the user's personal needs, so that the use...

third embodiment

[0155]FIG. 30 shows an adjustable dumbbell system 300 in accordance with the present invention. Similar to the previous embodiment, the adjustable dumbbell system 300 includes a base 310, a plurality of first weight plates 320A, a plurality of second weight plates 320B, a first auxiliary weight plate and a second auxiliary weight plate (hidden in the figure), and a handle assembly 302. FIG. 30 depicts that the handle assembly 302 mounting all weight plates 320A, 320B and auxiliary weight plates, forming the heaviest dumbbell 304.

[0156]The handle assembly 302 also includes a handle 330, a first end seat 340A and a second end seat 340B respectively connected to the two opposite ends of the handle 330, and two guide tubes 360 connected to the two end seats 340A, 340B along the longitudinal direction, and a first extension member 365A and a second extension member 365B respectively (at least partially) accommodated in the two guide tubes 360. Referring to FIG. 31, the operation principl...

fourth embodiment

[0161]FIG. 33 shows an adjustable dumbbell system 400 in accordance with the present invention. Except as otherwise described below, the adjustable dumbbell system 400 may be similar to the adjustable dumbbell system 100, 200, or 300, described above. For example, the adjustable dumbbell system 400 may include any combination of features disclosed above with reference to adjustable dumbbell system 100, adjustable dumbbell system 200, or adjustable dumbbell system 300. Without intent to limit, the adjustable dumbbell system 400 may include a handle 430, two guide tubes 460, and a first extension member 465A and a second extension member 465B accommodated in the two guide tubes 460.

[0162]The adjustable dumbbell system 400 may be adjusted in a manner similar to those described above. For example, rotating the handle 430 may drive a ring gear 471 (e.g., at each end) to rotate (e.g., about the longitudinal axis of the handle 430). The ring gear 471 may be formed or coupled with the handl...

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Ser. No. 63 / 746,358, filed Jan. 17, 2025, which is incorporated by reference herein in its entirety.

[0002] This application also claims priority to Taiwan Patent Application No. 114129713, filed Aug. 1, 2025, which is incorporated by reference herein in its entirety.BACKGROUND

[0003] Dumbbells are widely used exercise devices for providing resistance training in a wide variety of exercises such as bicep curls, bench presses, shoulder presses, triceps extensions, and the like. Due to the number of exercises that may be performed with dumbbells, users often use many different dumbbells, each with different weights, to perform an exercise routine. Traditional dumbbells are somewhat inconvenient to use because each time one desires to change the weight of the dumbbell, the user either has to select a heavier dumbbell, or disassemble the dumbbell and change the weight.

[0004] In response to these issues, adjustable dumbbells have been designed allowing a user to perform a varied exercise routine without requiring a large number of different weight dumbbells. Some of these adjustable dumbbells include a pair of rods that are slid outward from a mid-portion of the dumbbell near the handle to engage various weight plates to adjust the weight of the dumbbell. These adjustable dumbbells suffer from several drawbacks. For example, each rod is independently controllable and must be set by the user to assure the same number of weight plates, and thus the same amount of weight is coupled to each end of the handle. Failure to set the rods at the same length causes the dumbbell to be asymmetric and can be dangerous to use. Improved exercise devices are needed.BRIEF SUMMARY

[0005] In one embodiment, an adjustable dumbbell system includes a rotatable handle having a grip portion; at least one gear mechanism rotationally coupled to the rotatable handle; and at least one extension member operatively connected to the at least one gear mechanism. Upon rotation of the handle, the at least one extension member extends or retracts along an extension axis to selectively engage at least one weight plate and the handle.

[0006] Optionally in some embodiments, the rotatable handle includes a shaft, the shaft connected to the at least one gear mechanism, the at least one gear mechanism including a plurality of gears configured to cause movement of the at least one extension member upon rotation of the shaft.

[0007] Optionally in some embodiments, the gear mechanism includes a ring gear coupled to an end of the shaft, a respective pinon gear and a respective spur gear configured to mesh with a rack on each respective extension member.

[0008] Optionally in some embodiments, the gear mechanism includes a ring gear coupled to an end of the shaft and at least one of a worm gear or a spur gear configured to mesh with a rack on the extension member.

[0009] Optionally in some embodiments, the at least one gear mechanism includes a first gear mechanism disposed at a first end of the shaft and a second gear mechanism disposed at a second, opposite end of the shaft; the at least one extension member includes a first extension member operatively connected to one of the first gear mechanism or the second gear mechanism, and a second extension member operatively connected to the other of the first gear mechanism or the second gear mechanism; wherein, upon rotation of the handle, the first extension member and the second extension member synchronously extend or retract along respective extension axes to selectively engage at least one respective weight plate and the handle.

[0010] Optionally in some embodiments, the first extension member is disposed at a 3 o'clock, 4 o'clock, 5 o'clock, or 6 o'clock position, and the second extension member is disposed at a 6 o'clock, 7 o'clock, 8 o'clock, or 9 o'clock position with respect to an inner wall of the adjustable dumbbell.

[0011] Optionally in some embodiments, each of the weight plates include a recess adapted to receive the extension member.

[0012] Optionally in some embodiments, the adjustable dumbbell system includes a base including a plurality of positioning walls and positioning recesses configured to align the recess of the weight plates to form a channel that receives each of the extension members.

[0013] Optionally in some embodiments, the at least one extension member is disposed at a 3 o'clock, 4 o'clock, 5 o'clock, 6 o'clock, 7 o'clock, 8 o'clock, or 9 o'clock position with respect to an inner wall of the adjustable dumbbell.

[0014] Optionally in some embodiments, the adjustable dumbbell system includes at least one inner wall disposed at an end of the handle, wherein the handle and the gear mechanism rotate relative to the at least one inner wall.

[0015] Optionally in some embodiments, the adjustable dumbbell system includes a locking mechanism that prevents actuation of the gear mechanism when the dumbbell is disengaged from the base.

[0016] Optionally in some embodiments, the adjustable dumbbell system includes a base including a lock feature configured to engage with locking members on the dumbbell to prevent removal of the handle from the base when weight plates are improperly selected.

[0017] Optionally in some embodiments, the extension members include a plurality of detents configured to assist the user in selecting predetermined weight increments.

[0018] Optionally in some embodiments, the weight plates include opposing grooves and ridges that interlock to prevent dislodgement of the weight plates from the handle when the handle is removed from the base.

[0019] Optionally in some embodiments, the extension members include a stop to prevent overextension beyond a designated length.

[0020] In one embodiment, an adjustable dumbbell system includes a base; a plurality of weight plates configured to rest on the base; an adjustable dumbbell removably secured to the base, the dumbbell including: a rotatable handle, at least two extension members, at least two gear mechanisms, each of the at least two gear mechanisms operatively coupled to a respective one of the at least two extension members. The rotatable handle is operatively connected to the at least two gear mechanisms which extends the extension members along respective extension axes thereof to engage a selection of one or more weight plates from the base.

[0021] Optionally in some embodiments, the rotatable handle includes a shaft, the shaft connected to the at least two gear mechanisms, the at least two gear mechanisms each including a plurality of gears configured to cause synchronous movement of the at least two extension members upon rotation of the shaft.

[0022] Optionally in some embodiments, the at least two gear mechanisms each include a ring gear coupled to an end of the shaft, a pinon gear and a spur gear configured to mesh with a rack on each respective extension member.

[0023] Optionally in some embodiments, the at least two gear mechanisms each include a ring gear coupled to an end of the shaft and a spur gear or a worm gear configured to mesh with a rack on each respective extension member.

[0024] Optionally in some embodiments, each of the weights include a recess adapted to receive the extension member.

[0025] Optionally in some embodiments, the base includes a plurality of positioning walls configured to align the recess of each weight plate to form a channel that receives the extension member.

[0026] Optionally in some embodiments, the adjustable dumbbell system includes a locking mechanism that prevents actuation of the gear mechanism when the dumbbell is disengaged from the base.

[0027] Optionally in some embodiments, the base includes a lock feature configured to engage with locking members on the dumbbell to prevent removal of the handle from the base when weight plates are improperly selected.

[0028] Optionally in some embodiments, at least one of the at least two extension members includes a plurality of detents configured to assist the user in selecting predetermined weight increments.

[0029] Optionally in some embodiments, the weight plates include opposing grooves and ridges that interlock to prevent dislodgement of the weight plates from the handle when the handle is removed from the base.

[0030] Optionally in some embodiments, at least one of the at least two extension members includes a stop to prevent overextension beyond a designated length.

[0031] In one embodiment, a method of adjusting weight in a dumbbell system includes providing a dumbbell having a rotatable handle and two extension members coupled to a gear mechanism; rotating the handle to actuate the gear mechanism, thereby extending the extension members along respective extension axes; and selectively engaging weight plates positioned on opposite ends of the handle via the extension members to adjust a weight of the dumbbell.

[0032] Optionally in some embodiments, the method further includes locking the extension members in a desired position using a locking mechanism when the dumbbell is removed from the base.

[0033] Optionally in some embodiments, the handle rotation simultaneously actuates both extension members to ensure symmetric engagement of weight plates by the extension members.

[0034] In one embodiment, an adjustable dumbbell system includes a base having two opposite ends, and a longitudinal direction defined by the two ends; a plurality of first weight plates configured to rest on one end of the base along the longitudinal direction; a plurality of second weight plates configured to rest on the other end of the base along the longitudinal direction; and a handle assembly arranged between the two ends of the base. The handle assembly includes a handle configured for allowing a user to grasp, having a first end corresponding to the first weight plates and a second end corresponding to the second weight plates; a first end seat and a second end seat respectively connected to the first end and the second end of the handle; at least one enclosure connecting the first end seat and the second end seat along the longitudinal direction, wherein the at least one enclosure is located outside the handle and separated by a distance that does not hinder the user from gripping the handle; and a first extension member and a second extension member, each being operable to extend or retract into the enclosure along the longitudinal direction, the first extension member and second extension member being interconnected to each other, so that the first extension member and the second extension member can be operated to move in opposite directions in the longitudinal direction. The first extension member is operable to extend from the enclosure and the first end seat in a direction away from the second end seat to engage the first weight plates in sequence, and the second extension member is operable to extend from the enclosure and the second end seat in a direction away from the first end seat to engage the second weight plates in sequence, so that the handle assembly is operable to selectively engage the first weight plates and the second weight plates.

[0035] Optionally in some embodiments, the first end seat includes a first transmission mechanism operatively connected to the first extension member to convert a rotational movement into a linear movement of the first extension member in the longitudinal direction; the second end seat includes a second transmission mechanism operatively connected to the second extension member to convert a rotational movement into a linear movement of the second extension member in the longitudinal direction; and the rotational movement of the first transmission mechanism is interconnected with the rotational movement of the second transmission mechanism.

[0036] Optionally in some embodiments, the first extension member is provided with a first rack extending in the longitudinal direction, the first transmission mechanism having at least one first gear, one of the at least one first gear configured to mesh with the first rack on the first extension member; and the second extension member is provided with a second rack extending in the longitudinal direction, the second transmission mechanism having at least one second gear, one of the at least one second gear configured to mesh with the second rack on the second extension member.

[0037] Optionally in some embodiments, one of the at least one first gear of the first transmission mechanism is coaxially connected to one of the at least one second gear of the second transmission mechanism, with a rotation axis corresponding to the longitudinal direction and passing through an interior of the handle.

[0038] Optionally in some embodiments, the handle assembly is provided with a weight selection portion that can be rotated by the user, and rotation of the weight selection portion drives the first gear and the second gear to rotate synchronously; when the weight selection portion is operated to rotate in a forward rotation direction by a predetermined angle, the first extension member can be moved in the direction away from the second end seat by a predetermined distance, while the second extension member can be moved in the direction away from the first end seat by the predetermined distance simultaneously; and when the selection portion is operated to rotate in a reverse rotation direction by the predetermined angle, the first extension member can be moved in a direction close to the second end seat by the predetermined distance, while the second extension member can be moved in a direction close to the first end seat by the predetermined distance.

[0039] Optionally in some embodiments, the handle at least partially forms the weight selection portion, which can rotate about the rotation axis with respect to the first end seat and the second end seat.

[0040] Optionally in some embodiments, the adjustable dumbbell system includes a first auxiliary weight plate and a second auxiliary weight plate resting on predetermined positions of the base, respectively corresponding to locations of the first end seat and the second end seat of the handle assembly when resting on the base; the first end seat and the second end seat respectively provided with a first engaging member and a second engaging member that can be driven by the weight selection portion; wherein the weight selection portion is operable to be rotated to one of a plurality of predetermined angular positions; wherein when the weight selection portion is in some of the predetermined angular positions, the first engaging member and the second engaging member do not engage the first auxiliary weight plate and the second auxiliary weight plate; and wherein when the weight selection portion is in the others of the predetermined angular positions, the first engaging member and the second engaging member respectively engage the first auxiliary weight plate and the second auxiliary weight plate, so that the handle assembly is operable to selectively engage the first auxiliary weight plate and the second auxiliary weight plate.

[0041] Optionally in some embodiments, the first auxiliary weight plate and the second auxiliary weight plate each include a lock portion; the first engaging member and the second engaging member each include at least one convex lump, which can be driven by the weight selection portion to rotate around the rotation axis; when the weight selection portion is in some of the predetermined angular positions, all the convex lumps of the first and second engaging members are not blocked under the respective lock portions of the first auxiliary weight plate and the second auxiliary weight plate; and when the weight selection portion is in the others of the predetermined angular positions, one convex lump of the first engaging member is blocked under the lock portion of the first auxiliary weight plate, and one convex lump of the second engaging member is blocked under the lock portion of the second auxiliary weight plate.

[0042] Optionally in some embodiments, any two adjacent predetermined angular positions of the weight selection portion are separated by one unit angle; when the weight selection portion rotates one unit angle from one of the predetermined angular positions to another one, the handle assembly is operable to be changed from one state of engaging the first and second auxiliary weight plates to another state of disengaging the first and second auxiliary weight plates, or changed from the state of disengaging the first and second auxiliary weight plates to the state of engaging the first and second auxiliary weight plates; when the weight selection portion rotates one unit angle twice in the forward rotation direction from one of the predetermined angular positions to another one, the handle assembly is operable to additionally engage one of the first weight plates and one of the second weight plates; and when the weight selection portion rotates one unit angle twice in the reverse rotation direction from one of the predetermined angular positions to another one, the handle assembly is operable to disengage one of the first weight plates and one of the second weight plates.BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 is an isometric view of an embodiment of adjustable dumbbell system with the adjustable dumbbell resting in a base.

[0044] FIG. 2 is an isometric view of the adjustable dumbbell system of FIG. 1 with the adjustable dumbbell being removed from the base with a selection of weights coupled to the handle assembly of the adjustable dumbbell.

[0045] FIG. 3 is a simplified cross section of the adjustable dumbbell system of FIG. 1 taken along line 3-3 of FIG. 1.

[0046] FIG. 4 is a simplified cross section of an embodiment of weights of the adjustable dumbbell system of FIG. 1 taken along line 4-4 of FIG. 1.

[0047] FIG. 5A is a partial isometric view of the handle assembly of the adjustable dumbbell of FIG. 1 in a first configuration.

[0048] FIG. 5B is a partial isometric view of the handle assembly of the adjustable dumbbell of FIG. 1 in a second configuration.

[0049] FIG. 6 is a simplified cross section of the handle assembly of the adjustable dumbbell of FIG. 1 taken along line 6-6 of FIG. 1.

[0050] FIG. 7A is a simplified cross section of a portion of a locking mechanism of the adjustable dumbbell of FIG. 1 taken along line 6-6 of FIG. 1, in a first configuration.

[0051] FIG. 7B is a simplified cross section of a portion of a locking mechanism of the adjustable dumbbell of FIG. 1 taken along line 6-6 of FIG. 1, in a second configuration.

[0052] FIG. 8A is an enlarged cross-sectional view of a portion of the locking mechanism of the handle assembly of FIG. 1 taken along line 8A-8A of FIG. 7A with the locking mechanism in a first or unlocked position that permits rotation of the discs.

[0053] FIG. 8B is an enlarged cross-sectional view of the locking mechanism of FIG. 8A taken along line 8B-8B of FIG. 8A.

[0054] FIG. 8C is an enlarged cross-sectional view of a portion of the locking mechanism of the handle assembly of FIG. 1 taken along line 8C-8C of FIG. 7B with the locking mechanism is a second or locked position that prevents rotation of the discs.

[0055] FIG. 9A is an isometric view of an embodiment of a handle assembly suitable for use with the adjustable dumbbell system of FIG. 1

[0056] FIG. 9B is an elevation view of the handle assembly of FIG. 9A.

[0057] FIG. 10A is an isometric view of an embodiment of a handle assembly suitable for use with the adjustable dumbbell system of FIG. 1

[0058] FIG. 10B is an elevation view of the handle assembly of FIG. 10A.

[0059] FIG. 11 is a perspective view of a second embodiment of an adjustable dumbbell system with the adjustable dumbbell resting on a base.

[0060] FIG. 12 is a side view of the adjustable dumbbell system of FIG. 11.

[0061] FIG. 13 is a top view of the adjustable dumbbell system of FIG. 11.

[0062] FIG. 14 and FIG. 15 illustrate exploded views of the adjustable dumbbell system of the second embodiment, showing the relative relationship between a handle assembly, weight plates, auxiliary weight plates, and a base.

[0063] FIG. 16 is a perspective view of the adjustable dumbbell system of the second embodiment, showing the handle assembly removed from the base without any weight plates or auxiliary weight plates.

[0064] FIG. 17 is a perspective view of the adjustable dumbbell system of the second embodiment, showing the handle assembly removed from the base and mounted with or connected to all weight plates and auxiliary weight plates.

[0065] FIGS. 18A-18B are cross-sectional views of the adjustable dumbbell system along line I-I of FIG. 12. For clarity of illustration, FIG. 18A illustrates one side of the adjustable dumbbell system (e.g., a left side) along line I-I of FIG. 12, and FIG. 18B illustrates another side of the adjustable dumbbell system (e.g., a right side) along line I-I of FIG. 12, with FIG. 18A and FIG. 18B split across two drawing sheets.

[0066] FIG. 19 is a cross-sectional view of the adjustable dumbbell system along line II-II of FIG. 13.

[0067] FIG. 20 shows an assembly structure of metal components and plastic shell components of the handle assembly of the second embodiment.

[0068] FIG. 21 shows the assembly structure of the handle and the indexing discs of the handle assembly of the second embodiment.

[0069] FIG. 22 is a perspective view of the handle assembly of the second embodiment, removing some of the components and showing the transmission method of a first transmission mechanism.

[0070] FIG. 23 is another perspective view of the handle assembly of the second embodiment, removing some of the components and showing the transmission method of a second transmission mechanism.

[0071] FIG. 24A is a cross-sectional view of the adjustable dumbbell system along line III-III of FIG. 19, wherein an indexing disc is at a predetermined angular position.

[0072] FIG. 24B is similar to FIG. 24A, except that the indexing disc is at another predetermined angular position.

[0073] FIG. 25A is an enlarged view of the indicated portion of FIG. 19, wherein the indexing disc is at a predetermined angular position.

[0074] FIG. 25B is similar to FIG. 25A, but with the indexing disc not positioned at a predetermined angular position.

[0075] FIG. 26 is a side view of the adjustable dumbbell system of the second embodiment, showing the handle assembly mounted with two weight plates and one auxiliary weight plate at each end when removed from the base.

[0076] FIG. 27 is a cross-sectional view corresponding to the adjustable dumbbell system shown in FIG. 26.

[0077] FIG. 28 is an enlarged view of the indicated portion of FIG. 27.

[0078] FIG. 29 is a side view of the adjustable dumbbell system of the second embodiment, showing the handle assembly mounted with three weight plates at each end and without auxiliary weight plates when removed from the base.

[0079] FIG. 30 is a perspective view of a third embodiment of an adjustable dumbbell system, showing a handle assembly mounted with all weight plates and auxiliary weight plates when removed from the base.

[0080] FIG. 31 is a perspective view of the adjustable dumbbell system of the third embodiment, removing some of the components and showing the internal structure of the end seat of the handle assembly and its relationship with the base.

[0081] FIG. 32A is a cross-sectional view of the adjustable dumbbell system of the third embodiment, wherein the handle assembly is placed on the base.

[0082] FIG. 32B is similar to FIG. 32A, but showing the handle assembly removed from the base.

[0083] FIG. 33 illustrates a fourth embodiment of an adjustable dumbbell system, showing a spur gear to worm-rack configuration of adjusting the dumbbell system.

[0084] FIG. 34 illustrates a fifth embodiment of an adjustable dumbbell system, showing a direct worm gear to rack configuration of adjusting the dumbbell system.DETAILED DESCRIPTION

[0085] The present disclosure provides an adjustable dumbbell system which allows a user to select a dumbbell weight. Referring to FIG. 1 and FIG. 2, an adjustable dumbbell system 100 may include an adjustable dumbbell 102 and a base 104. To change the weight of the dumbbell 102, the user may place the dumbbell 102 in the base 104, turn a handle 106 of the dumbbell 102 to engage a desired combination of weight plates 108, and remove the dumbbell 102 from the base 104 to perform a desired exercise.

[0086] The desired combination of weights may be coupled to the handle 106, and unused weights may remain in the base 104. Should the user desire a different dumbbell weight, the user may place the dumbbell 102 back in the base 104, turn the handle 106 to engage the desired weight plates 108, and remove the dumbbell 102 from the base 104 with the desired weight. When the adjustable dumbbell 102 is not in the base 104, for example during exercise-type use, the adjustable dumbbell 102 may be configured such that it is difficult to add or remove weight plates 108.

[0087] The base 104 may receive the dumbbell 102 and may allow a user to adjust the weight of the dumbbell 102. During use of the dumbbell 102, the base 104 may hold the weight plates 108 that are not attached to the dumbbell 102. Before using the dumbbell 102, the user may first determine the weight to be lifted and turn the handle 106 while the dumbbell 102 is in the base 104, causing no weights or one or more weight plates 108 to be fixedly connected to a handle assembly 114. The user may then lift the dumbbell 102 out of the base 104. Any weight plate 108 not fixedly connected with the adjustable dumbbell 102 remains in the base 104. The weight plates 108 may be all the same weight or may have different weights to allow for more flexibility in the user selection of the one or more weight plates 108.

[0088] The base 104 may include a bottom wall 109, one or more positioning walls 110 with positioning recesses 196 therebetween, and a pair of lock features 112. The bottom wall 109 may support the adjustable dumbbell 102 and the weight plates 108. The positioning walls 110 and positioning recesses 196 may ensure that the adjustable dumbbell 102 is properly aligned when it is inserted into the base 104. The positioning walls 110 and / or positioning recesses 196 may hold the weight plates 108 upright and in the proper location relative to the handle assembly 114 so that the adjustable dumbbell 102 may be inserted into and removed from the base 104. The positioning walls 110 may be spaced so as to fit between adjacent weight plates 108 when the dumbbell 102 rests in the base 104 and to keep any weight plate 108 not attached to the dumbbell 102 upright when the dumbbell 102 is removed from the base 104.

[0089] The dumbbell 102 includes a gear mechanism 198 rotatably engaged with the handle, such that as the handle 106 is rotated by the user, while in the base 104, the gear mechanism 198 causes an extension member 179 to move (extend or retract) along an extension axis 191 of the extension member 179 and engage a desired number of weight plates 108. In some embodiments, the dumbbell 102 may have a gear mechanism 198 at each end of the handle 106. In such embodiments, the rotation of the handle 106 causes a synchronous movement of gear mechanisms 198 and thus synchronous movement of the extension members 179 to engage a same number of weight plates 108 at each end of the handle 106.

[0090] The disclosure herein may be applicable to both ends of the dumbbell 102, e.g., the left and right sides thereof. For brevity, only one side of the dumbbell may be described.

[0091] Referring to FIG. 3-FIG. 6, the handle 106 of the adjustable dumbbell 102 may include a grip portion 128 and a rotatable member 132, such as a sleeve or the like. The grip portion 128 may be mounted onto the rotatable member 132 and may be slightly bulged to provide a comfortable and ergonomic surface to grasp to facilitate a user securely gripping the adjustable dumbbell 102. The grip portion 128 may be generally symmetrical about the midpoint of the rotatable member 132. The rotatable member 132 may be coupled (e.g., rotationally coupled) to a shaft 127 that effectuates user selection of the weight plates 108. For example, the dumbbell 102 may include one or more extension members 179 that extend along respective their extension axis 191 to select different weight plates 108 in response to an input from the user to the handle 106.

[0092] The extension members 179 may be at least partially enclosed in respective enclosures 189 (e.g., tubes), or in one enclosure 189 together (see, e.g., FIG. 10A and FIG. 10B). In the embodiment shown for example in FIG. 1-FIG. 7B, the enclosures 189 and / or extension members 179 may be disposed at the 3 o'clock and 9 o'clock positions about the inner walls 169 when dumbbell 102 is viewed from an end (e.g., an elevation view such as shown for example in FIG. 6.) In other embodiments, the enclosures 189 may be disposed at other positions, such as 4 o'clock and 8 o'clock positions, 5 o'clock and 7 o'clock positions, or other positions as desired. For example, the extension members 179 may be disposed at the 3 o'clock and 9 o'clock positions forming a cord the same or nearly the same dimension as the inner wall 169, e.g., may be diametrically spaced apart. In other examples, the extension members 179 may be more closely grouped with one another, e.g., disposed at 4 o'clock and 8 o'clock positions forming a cord with a dimension less than that of the inner wall 169. In such embodiments, the extension members 179 may be disposed in a lower portion of the inner wall 169. In other examples still, the extension members 179 may be even more closely more closely grouped with one another, e.g., disposed at 5 o'clock and 7 o'clock positions forming a cord with a dimension less than that of the 4 o'clock and 8 o'clock positions. In some embodiments, the extension members 179 may be unevenly or asymmetrically spaced about the inner wall 169. In other embodiments still, the extension members 179 may be disposed with at least a portion of the extension members 179 at or near the 6 o'clock position. In some embodiments, the extension members 179 may be disposed at the 5:30 and 6:30 positions (e.g., with one extension member 179 at an hour hand position and another extension member 179 at a minute hand position of a clock face).

[0093] See e.g., FIG. 9A-FIG. 10B showing alternate embodiments with placements of the extension members 179 and / or enclosures 189 such as to facilitate user access to the handle 106.

[0094] The shaft 127 may be received through a generally circular passage defined by the rotatable member 132. Each end portion 130 of the shaft 127, one on either end of the rotatable member 132, may extend beyond a respective end of the rotatable member 132. The rotatable member 132 may be rotatable about a longitudinal axis 134 of the shaft 127 to allow a user to select a desired dumbbell weight plate 108 by rotating the handle 106. In many embodiments, the rotatable member 132 and the shaft 127 may rotate in unison about the longitudinal axis 134 of the shaft 127.

[0095] With particular reference to FIG. 3, the shaft 127 may be coupled to bearings 171 e.g., at the end portions 130. For example, an inner race of the bearings 171 may be coupled to the shaft 127 while an outer race of the bearings 171 is coupled to the inner walls 169, thus allowing relative rotational movement between the handle 106, the rotatable member 132, the grip portion 128, and / or the shaft and the inner walls 169.

[0096] With particular reference to FIG. 5A and FIG. 5B, the shaft 127 or the bearings 171 may be coupled to respective gear mechanisms 198. The gear mechanisms 198 may include ring gears 173, pinons 175, spur gears 177, and / or a rack 181 formed with or coupled to the extension members 179. In some embodiments, one or more components of the gear mechanism 198 may be optional, may be replaced with other components, or include additional components. In some embodiments, the gears of the gear mechanism 198 may be replaced with toothless discs, pulleys, belts, or other devices. For example, the ring gears 173 may rotate in unison with the shaft 127. The ring gears 173 may be bevel gears with teeth suitable to mesh with and drive other gears or components. A pinon 175 may be rotationally mounted to the inner wall 169 such that its teeth mesh with those of the ring gear 173 and the pinon 175 may be driven by the ring gear 173 about a rotation axis. 193. A spur gear 177 may be mounted, and rotatable with, the pinon 175 such that the spur gear 177 and the pinon 175 rotate in unison about the rotation axis 193. The teeth of the spur gear 177 mesh with corresponding teeth of a rack 181 formed with or coupled to the extension member 179

[0097] As shown for example in FIG. 5A and FIG. 5B, as the user rotates the handle 106, the shaft rotates with the handle 106 about the longitudinal axis 134. FIG. 5A shows example alignment marks stationary mark 502 and a rotational mark 504. These marks may not be included in the actual dumbbell 102, but are shown to illustrate the mechanism of action of the dumbbell 102 to enable a user to select different weight plates. In FIG. 5A, the stationary mark 502 and the rotational mark 504 are substantially aligned. The extension members 179 are retracted within enclosures 189 coupled to the inner walls 169 and disposed about the ring gear 173. In the configuration of FIG. 5A, no weight plates 108 may be selected. As a user rotates the handle 106, and thus the shaft 127, (e.g., counterclockwise as shown in FIG. 5A) the ring gear 173 rotates in the same direction as the handle 106, e.g., in a rotation direction 195 about the longitudinal axis 134 either or both clockwise and / or counterclockwise. The teeth of the ring gear 173 mesh with corresponding teeth of the pinon 175 causing the pinon 175 to rotate about the rotation axis 193. The spur gear 177 rotates with the pinon 175. In some embodiments, the pinon 175 and the spur gear 177 may be combined (e.g., with one set of teeth). The teeth of the spur gear 177 mesh with the teeth of the rack 181 and as the spur gear 177 rotates about the rotation axis 193 causing the extension member 179 to extend away from the middle portion of the dumbbell 102. See, e.g., FIG. 5B, showing both extension members 179 in an extended position suitable to engage weight plates 108. See also, FIG. 2 showing the extension member 179 engaging with the recess 183 formed in the weight plates 108. Optionally in some embodiments, one or more of the extension members 179 may include a detent 140 (see FIG. 5A and FIG. 5B) or similar mechanism to aid in selecting a discrete weight plate 108 selection. For example, the extension member 179 may include a plurality of notches and the handle assembly 114 may include a biased rolling member like a ball that “clicks” or “snaps” into place when the extension member 179 is at the appropriate extension to select a weight. In some embodiments, the extension members 179, the ring gear 173, the indexing disc 120 or another portion of the handle assembly 114 may include a stop to prevent overextension of the extension members 179 beyond a desired length.

[0098] As shown for example in FIG. 5B, the rotation of the handle 106 simultaneously or synchronously causes movement of both extension members 179 (via the opposing ring gears 173, pinons 175 and spur gears 177 at each end of the dumbbell 102) a same amount along their respective extension axes 191. Thus, with a single rotation of the handle 106, the user can select the same amount of weight on each end of the dumbbell, which is a significant advantage in ease of use and speed compared to existing adjustable dumbbells.

[0099] With reference to FIG. 3 and FIG. 4, when the handle assembly 114 is removed with a weight plate 108 selection from the base 104, the weight plates 108 are secured to the handle assembly 114. In the vertical direction, the weight plates 108 are held to the handle assembly 114 by the interaction of the extension member 179 and the recess 183 formed in the weight plates 108. E.g., each weight plate 108 has a notch or recess formed therein. The recess 183 may be located at an edge of the weight plate 108 or may be located in the main body of a weight plate 108, not touching the outer edge of the weight plate 108. When the weight plates 108 are resting in the base 104 (e.g., against the positioning walls 110), the recesses 183 align with one another to form an elongated channel that receives varying lengths of the extension member 179 based on the handle 106 position. In the extension direction (e.g., left and right along the extension axis 191) each weight plate is secured to a subsequent weight plate. See e.g., FIG. 4 showing each weight plate 108 having a ridge 187 on one face thereof and a corresponding groove 185 on another, opposite face thereof. When resting in the base or attached to the handle assembly 114, the ridge 187 of one plate slides into the groove 185 of the plate next to it and so forth, thereby securing the weight plates 108 to the handle assembly 114. In the example shown, the groove 185 and ridge 187 form a dovetail arrangement, with the ridge 187 having a flared portion extending laterally that prevents the ridge 187 from being pulled along the extension axis 191 direction out of the groove 185 of the adjacent weight plate 108. In some embodiments, the notches and or recesses may be v-shaped to help further secure weight plates from relative vertical movement when the dumbbell 102 is removed from the base.

[0100] The handle assembly 114 has several advantages over existing adjustable dumbbells. For instance, with a single user input (e.g., rotation of the handle 106), the user can select weight plate 108 on both ends (e.g., left and right ends) of the dumbbell 102. With many existing adjustable dumbbells, the user must separately select weight on each end of the dumbbell, which is time-consuming, and prone to error. Furthermore, some existing adjustable dumbbells have a handle assembly that extends the same distance regardless of which weights are selected. In other words, such dumbbells are the same length regardless of whether 2 kg or 25 kg is selected. This makes such dumbbells awkward to use for some exercises.

[0101] Furthermore, the adjustable dumbbell system 100 disclosed herein is advantageous over existing dumbbells because the dumbbell 100 includes a locking mechanism 142 that prevents a user from removing the handle assembly 114 from the base 104 when an extension member 179 is between weight selections, and prevents a user from retracting or extending the extension members 179 when the handle assembly 114 is off the base, e.g., to avoid dropping weight plates during an exercise, which is a potential safety hazard.

[0102] Referring to FIG. 7A-FIG. 8C, the adjustable dumbbell system 100 includes a locking mechanism 142 that serves at least two purposes. First, the locking mechanism 142 prevents a user from removing the dumbbell 102 from the base 104 when the handle 106 is positioned between weight selections, e.g., one or more weight plates 108 are partially, but not fully engaged with the dumbbell 102. This function prevents partially selected weights from falling or snagging on the base 104 or other portion of the adjustable dumbbell system 100.

[0103] After a user has fully selected a weight and lifted the dumbbell 102 from the base 104 (e.g., As shown for example in FIG. 2), the locking mechanism 142 prevents the user from changing the weight plate 108 selection while the dumbbell 102 is not secured on the bottom wall 109. This feature prevents the user from dropping weight plates 108 while the dumbbell 102 is in use. In some embodiments, the locking mechanism 142 and related mechanisms and components may be as described in U.S. Patent Publication US 2015 / 0360073, which is hereby incorporated by reference herein in its entirety and for all purposes.

[0104] The locking mechanism 142 includes lock features 112. The lock features 112 may be formed from a relatively rigid metal, plastic, or other suitable material. Each lock feature 112 may extend upwardly from the base 104, e.g., from the bottom wall 109. In some embodiments, each lock feature 112 may include a plate-like vertical portion that extends upwardly from the base 104 with a plate-like horizontal portion that extends substantially perpendicular from an end portion of the vertical portion that is distal from the base 104. The arrangement of the vertical and horizontal portions of each lock feature 112 may resemble an L-shaped profile for the portion of the lock feature 112 extending above the base 104. The lock features 112 may be positioned on the base 104 to extend into a cavity formed in the adjustable dumbbell 102 when the dumbbell 102 is placed in the base 104. The lock features 112 may deactivate a locking mechanism, as described further below, to allow selection of different weights when the adjustable dumbbell 102 is in the base 104. In some embodiments, the locking mechanism 142.

[0105] The handle assembly 114 may include an inner cover 118 (shown in dashed lines in FIG. 1 and the details of FIG. 8A and FIG. 8B) that encloses or hides a portion of the locking mechanism 142. The handle assembly 114 may include indexing discs 120 which may be mounted onto the handle 106 immediately distal or outside of the inner covers 118, e.g., on an inner wall 169. The inner covers 118 or inner walls 169 may include a locking mechanism 142 that permits or prevents rotation of the handle 106. The locking mechanism 142 may include a locking member 144, such as a spring-loaded button. The locking member 144 may include an interference feature 145, such as a protrusion or a projection, which extends in a distal direction parallel or generally parallel to a longitudinal axis 134 of the handle 106 or the shaft 127 and toward the indexing discs 120. The locking member 144 may be vertically movable relative to the inner covers 118 and / or inner wall 169 and may be laterally restrained in directions oriented transversely (e.g., orthogonally) to the direction of movement, such as in a rotation direction of the ring gear 173.

[0106] Turning to FIG. 8A, the locking member 144 may be downwardly biased toward an opening 148 by a lock bias member 146, such as a spring, which may be arranged along a vertically oriented axis. The opening 148 may be defined by the inner cover 118 and / or the inner wall 169. The opening 148 may be downwardly extending to expose a lower surface of the locking member 144 to permit a portion of the base 104 to engage and vertically displace the locking member 144 against the bias of the lock bias member 146. The locking member 144 may be vertically displaced within a cavity 150 defined by the inner cover 118. The inner covers 118 may include cover plates 152, which may be removably attached to the inner or proximal surface of the inner covers 118 to provide access to the locking members 144 and the lock bias members 146. The cover plates 152 may also provide a bearing surface for the locking members 144 to slide along during vertical displacement of the locking members 144 relative to the inner covers 118.

[0107] Referring to FIG. 8A-FIG. 8C, the locking mechanism 142 of the inner cover 118 may be biased to engage an associated lock feature 154 to prevent the indexing discs 120 from rotating about the longitudinal axis of the shaft 127 and / or relative to the weights 108 when the handle assembly 114 of the dumbbell 102 is removed from the base 104. Upon removal of the handle assembly 114 from the base 104, each locking member 144 interferes with a respective indexing disc 120 to prevent rotation of the indexing discs 120. This interference may occur by each locking member 144 engaging the lock feature 154 on a respective indexing disc 120. In some implementations, such as implementations in which the lock feature 154 is two or more teeth and the interference feature 145 is a protrusion, upon removal of the dumbbell 102 from the base 104, lock bias members 146 bias respective locking members 144 into a locking position in which each locking member's protrusion is disposed between adjacent teeth of respective indexing discs 120, thereby preventing rotation of the indexing discs 120, and hence rotation of the separator discs and the selector discs 122, relative to the weights 108.

[0108] Referring to FIG. 7A-FIG. 8C, when the dumbbell 102 is placed in the base 104, the locking mechanism 142 may be moved into a disengaged or unlocked position. Upon placement of the dumbbell 102 onto the base 104, the lock feature 112 of the base 104 disengages the locking mechanism 142 from the lock feature 154 of the indexing disc 120 to allow rotation of the indexing disc 120 about the longitudinal axis of the shaft 127 and / or relative to the weight plates 108. In some embodiments, the lock feature 112 of the base 104 may extend upwardly through the opening 148 of the inner cover 118 and may drive the locking mechanism 142 upwardly. The lock feature 112 may move the locking member 144 upwardly a sufficient distance to displace the interference feature 145 (e.g., a protrusion, projection, or the like) from the rotational path of the lock feature 154 (e.g., teeth or the like) of the indexing disc 120 so that the indexing disc 120 may be turned to adjust the weight of the adjustable dumbbell 102. Thus, when the dumbbell102 is seated in the base 104, the weight of the adjustable dumbbell 102 may be adjusted by turning the rotatable member 132 of the handle 106 to selectively engage or disengage the weight plates 108 with the indexing discs 120.

[0109] The adjustable dumbbell 102 may not be removed from the base 104 unless the weight plates 108 have a predetermined level of engagement or disengagement with the indexing discs 120 and the extension members 179. The removal of the adjustable dumbbell 102 from the base 104 may be prevented when the base's lock feature 112 engages with the lock features 154 of the indexing disc 120 based on a rotational orientation of the handle 106. In some implementations of this locking system, the lock feature 154 for each indexing disc 120 may rotate beneath an upper portion 167 of a respective lock feature 112 when the dumbbell 102 is placed in the base 104. For embodiments in which the lock feature 154 is teeth, the teeth may be circumferentially spaced apart sufficiently to allow the upper portion 167 of the lock feature 112 to pass between adjacent teeth when the indexing discs 120 and extension members 179 are positioned at respective predetermined rotational (e.g., in a rotation direction 195) and extensional positions (e.g., along the extension axis 191) relative to the weight plates 108 to permit removal of the dumbbell 102 from the base 104. Additionally, the teeth may be circumferentially spaced apart sufficiently to inhibit the upper portion 167 of the lock feature 112 from passing between adjacent teeth 154 when the indexing discs 120 are not positioned at predetermined rotational positions relative to the weight plates 108 to prevent removal of the dumbbell 102 from the base 104, thus effectively locking the dumbbell 102 to the base 104. The predetermined rotational positions may be selected so that any weight plate 108 that is intended to be fixedly joined to the handle assembly 114 based on the relative rotational positions of the indexing discs 120 to the weight plates 108 is sufficiently engaged with its respective indexing disc 120.

[0110] When the weight plates 108 are not engaged with or disengaged from the indexing discs 120 as desired, a tooth of the indexing disc 120 may engage the upper portion 167 of the lock feature 112 and prevent the lock feature 112 from exiting through the opening 148 of the inner cover 118, thus locking the dumbbell 102 to the base 104. When the indexing discs 120 are properly aligned rotationally, the extension members 179 are aligned properly with the weights in the recess 183, the upper portion 167 of the lock feature 112 may pass between adjacent teeth 154, and the dumbbell 102 may be removed from the base 104. During removal of the dumbbell 102 from the base 104, the lock bias member 146 may bias the locking member 144 downwardly such that the interference feature 145 interacts with the indexing disc's lock feature 154 to prevent the indexing discs 120 from rotating relative to the inner covers 118, inner walls 169, and the weight plates 108. Thus, when removed from the base 104, the weight of the dumbbell 102 may be fixed until the dumbbell 102 is repositioned onto the base 104 to select a different combination of weights.

[0111] When the dumbbell 102 is set into the base 104, the lock feature 112 may engage the locking member 144 to disengage the locking member 144 from the indexing discs 120. The handle 106 may then be rotated to rotate the ring gear 173, pinon 175, and spur gear 177, and extend or retract the extension members 179 to select the desired number of weight plates 108. The detents 140 (see, FIG. 5A and FIG. 5B) may help the user identify when the dumbbell 102 is at a secure location rotationally and not between locations for selecting weight plates 108. The indicator markings 166 on the indexing disc 120 may be visible through a window to indicate that the desired weight is selected (see FIG. 8A-FIG. 8C). In between weight selection locations, the lock feature 154 on the indexing discs 120 may engage the lock feature 112 on the base 104 to prevent the dumbbell 102 from being removed from the base 104. When the indexing discs 120 are in a proper rotational orientation, the base's lock feature 112 does not engage the indexing disc's lock feature 154, thus allowing the dumbbell 102 to be removed from the base 104.

[0112] As the dumbbell 102 is removed from the base 104, the base's lock feature 112 ceases to engage the locking member 144, thus allowing the locking member 144 to be biased into a locking position in which the interference feature 145 interacts with the indexing disc's lock feature 154 to keep the indexing discs 120 from rotating relative to the weight plates 108. The locked nature of the indexing discs 120 may prevent independent rotation of the indexing disc 120 and thus extension or retraction of the extension members 179, via the ring gear 173, pinon 175 and spur gear 177, since the indexing disc 120 may be rotationally locked with the ring gear 173. Thus, when the dumbbell 102 is removed from the base 104, the indexing discs 120 are not rotatable, and the extension members 179 not moveable along the extension axis 191 to change the weight selection or cause the weight plates 108 on the dumbbell 102 to become dislodged. The lock feature 154 may be positioned proximate to the periphery of the indexing disc 120. In some embodiments, the lock feature 154 may be castellated teeth arranged around the perimeter 161 of the indexing disc 120. Each tooth may extend towards the inner covers 118 in a direction parallel, or generally parallel, to a longitudinal axis 134 of the handle 106 and / or shaft 127 and / or the extension axis 191 of the extension members 179.

[0113] FIG. 9A and FIG. 9B show an embodiment of the handle assembly 114 where the extension members 179 are disposed at a lower portion of the inner walls 169 (e.g., at 5 o'clock and 7 o'clock positions). This embodiment facilitates easier grasping of the handle 106 by the user by placing the extension members 179 and their enclosures 189 lower on the dumbbell 102.

[0114] FIG. 10A show an embodiment of the handle assembly 114 where the extension members 179 are disposed at a lower portion of the inner walls 169 (e.g., at a 6 o'clock position). This embodiment also facilitates easier grasping of the handle 106 by the user by placing the extension members 179 and their enclosures 189 lower on the dumbbell 102. This embodiment also has fewer parts as both extension members 179 may be enclosed in a single enclosure 189, and thus may be less costly to produce.

[0115] FIGS. 11, 12 and 13 are respectively a perspective view, a side view and a top view of an adjustable dumbbell system 200 (hereinafter, sometimes simply referred to as an adjustable dumbbell) in a standby state according to a second embodiment of the present invention. With additional reference to FIG. 14 and FIG. 15, the adjustable dumbbell system 200 includes a base 210, a plurality of first weight plates 220A, a plurality of second weight plates 220B, a first auxiliary weight plate 225A, a second auxiliary weight plate 225B and a handle assembly 202, or a combination thereof, that can be separated or combined with each other. In terms of weight selection function, the user can selectively attach the first and second weight plates 220A, 220B (hereinafter, sometimes simply called weight plates) and / or the first and second auxiliary weight plates 225A, 225B (hereinafter, sometimes simply called auxiliary weight plates) to the handle assembly 202 according to the user's personal needs, so that the user is able to grasp the adjustable dumbbell with the required weight to perform weight training. In some cases, FIG. 16 shows that the handle assembly 202 does not mount any weight plates 220A, 220B or auxiliary weight plates 225A, 225B, forming the lightest dumbbell 204; and FIG. 17 shows that the handle assembly 202 mounts all weight plates 220A, 220B and auxiliary weight plates 225A, 225B, forming the heaviest dumbbell 204.

[0116] The base 210 is elongated as a whole and can be placed horizontally (e.g., flat or relatively flat) on a plane such as the ground, floor, stand, table or a desktop. The base 210 may define a longitudinal direction (i.e., the relative direction of two opposite ends of the base 210, corresponding to the x-axis in FIGS. 11 to 13), a width direction (corresponding to the z-axis in FIGS. 11 and 13), and a height direction (corresponding to the y-axis in FIGS. 11 and 12) that are perpendicular to one another. Although the spatial relationships of the handle assembly 202, the weight plates 220A, 220B and the auxiliary weight plates 225A, 225B relative to the base 210 may change (for example, when a user lifts up the dumbbell 204 for weight training) , in order to facilitate the explanation of the structure of each component and the cooperation relationship between them, the aforementioned longitudinal direction, width direction and height direction will be applied to the handle assembly 202, the weight plates 220A, 220B, and the auxiliary weight plates 225A, 225B hereinafter according to the corresponding relationship in the standby state as shown in FIGS. 11 to 13. For example, unless otherwise specified, the terms “above”, “below”, “top side”, “bottom side” or similar terms below are based on the aforementioned height direction (y-axis) in the standby state. In addition, the “inner side” in the longitudinal direction (x-axis) refers to the side close to the center of the base 210 in the standby state, and the “outer side” refers to the side away from the center of the base in the standby state.

[0117] Next, the detailed structures of the base 210, weight plates 220A, 220B, auxiliary weight plates 225A, 225B, and the handle assembly 202 and their coordination will be described in order. If necessary, please refer to FIG. 18A18B and FIG. 19, which are horizontal (x-z plane) and vertical (x-y plane) cross-sectional views of the adjustable dumbbell system 200 in the standby state shown in FIG. 11.

[0118] Referring to FIG. 17, the base 210 can be divided into two opposite halves that are mirror-symmetric. At the terminal ends of the base 210, there are two side walls 211 facing each other. As shown in FIG. 19, a handle portion 212 is formed on the outside of the top of each side wall 211 to facilitate the user in moving the entire adjustable dumbbell system with two hands. The inner side of each side wall 211 has a protrusion 213 extending upward from the bottom of the side wall 211. The width of the protrusion 213 in the width direction gradually decreases from bottom to top, and its horizontal cross section has a dovetail shape, as depicted in FIG. 18A. Each half of the base 210 has a positioning recess 214 disposed on the inner side of the base 210, and a bump 215 located at the center of the outer side of the positioning recess 214. A hook 216 formed by a bending metal sheet is mounted between the bump 215 and the positioning recess 214, and the exposed part of the hook 216 extends upward and then extends inward, forming an inverted L shape when viewed from the side.

[0119] Referring to FIG. 14, the adjustable dumbbell system 200 includes five first weight plates 220A and five second weight plates 220B. The first weight plates 220A and the second weight plates 220B have identical shapes and structures, which are approximately circular in shape. In practice, each weight plate may be made of a plastic-coated metal sheet, or may be an integrated metal part or combined with plastic parts. Weight plates 220A, 220B are shown in cross section in FIGS. 18, 19, and 27 generally. However, the specific cross-sectional structures of the weight plates 220A, 220B are omitted in the cross-sectional views. One side surface (outer side surface) of each weight plate 220A, 220B has a groove 221 extending upward from the bottom edge. The width of the groove 221 in the width direction gradually decreases from bottom to top, and its horizontal cross section is dovetail-shaped, as depicted in FIG. 18B. Corresponding to the groove 221, the other side surface (inner side surface) of each weight plate 220A, 220B has a ridge 222 extending upward from the bottom edge. The width of the ridge 222 in the width direction gradually decreases from bottom to top, and its horizontal cross section is dovetail-shaped, as depicted in FIG. 18. In addition, each weight plate 220A, 220B has a recess (or notch) 223 formed on a predetermined side according to the width direction. The recess 223 passes through each weight plate 220A, 220B from the inner side surface to the outer side surface in the longitudinal direction, and its cross section is generally rectangular. In this embodiment, the recess 223 may recess from the side edge of each weight plate 220A, 220B towards to the center. In other embodiments, the recess 223 of the weight plate may be a through hole with a complete inner circumference (e.g., a rectangular hole with four walls), not touching the outer edge of the weight plate. Each first weight plate 220A and each second weight plate 220B may have the same predetermined weight, which is set to 5 pounds (about 2.27 kg) in this embodiment.

[0120] In the standby state as shown in FIGS. 11 to 13, the five weight plates (referred to as the first weight plates) 220A are arranged at one end of the base 210 along the longitudinal direction, and the other five weight plates (referred to as the second weight plates) 220B are arranged at the other end of the base 210 along the longitudinal direction. Each weight plate 220A, 220B is placed upright, having the side surface (i.e., the inner side surface) with the ridge 222 facing the center of the base 210, and the side surface (i.e., the outer side surface) with the groove 221 facing away from the center of the base 210. The first weight plate 220A and the second weight plate 220B, located on the outermost sides, respectively abut against the two side walls 211 at the terminal ends of the base 210, and the grooves 221 on the outer sides of the weight plates 220A, 220B are engaged with the protrusions 213 on the inner sides of the side walls 211. At the same time, any two adjacent first weight plates 220A or any two adjacent second weight plates 220B are engaged with each other through the grooves 221 and the ridges 222, so that the opposite sides of the adjacent two weight plates are appropriately against each other and their outer edge are overlapped. Thus, the first weight plates 220A are neatly placed between the side wall 211 and the bump 215 on one half of the elongated base 210, and the recesses 223 of the first weight plates 220A are all aligned on one side according to the width direction to form a first channel 224A extending along the longitudinal direction, as shown in the lower portion of FIG. 13. The second weight plate 220B are neatly placed between the side wall 211 and the bump 215 on the other half of the elongated base 210, and the recesses 223 of the second weight plates 220B are all aligned on the other side according to the width direction to form a second channel 224B extending along the longitudinal direction, as shown in the upper portion of FIG. 13.

[0121] Based on the aforementioned engagement structure, any weight plate 220A, 220B on the base 210 can be moved upward along the extension direction of the groove 221 and detached from the other weight plate 220A, 220B on the base 210 located on its outer side or the side wall 211. Similarly, the weight plate 220A, 220B outside the base 210 can allow the groove 221 on its outer side to align and move downward to engage the ridge 222 on the inner side of the other weight plate 220A, 220B on the base 210 or the protrusion 213 on the inner side of the side wall 211, allowing the weight plate to return to the preset position of the standby state. Referring to FIGS. 18A-18B, since the concave and convex locking features between the adjacent two weight plates are dovetail-shaped, the two weight plates cannot be separated in other directions other than in the height direction. In the present embodiment, the grooves 221, the ridges 222 and the protrusions 213 are designed to gradually narrow from bottom to top to facilitate engagement and separation, and the engagement can be tight. In other embodiments, each weight plate may be provided with a groove (e.g., gradually narrowing downward from the top edge) on the inner side, and a ridge on the outer side that matches the groove. In addition, embodiments may adopt a weight plate interlocking structure similar to that disclosed in U.S. Pat. Nos. 9,643,042 or 6,149,558, or using a plurality of connecting rods extending along the longitudinal direction to connect the symmetrically positioned first weight plates and second weight plates in pairs, similar to the U.S. Pat. No. 7,090,625.

[0122] Referring to FIG. 15, the shape and structure of the first auxiliary weight plate 225A and the second auxiliary weight plate 225B are entirely the same, and their appearance is similar to a U-shaped plate. Similarly, in practice, the auxiliary weight plates may be made of a plastic-coated metal sheet, or may be an integrated metal part or combined with other plastic parts. Each auxiliary weight plate 225A, 225B has a lock portion 226 protruded outward approximately in the center of one side (outer side) thereof. The first auxiliary weight plate 225A and the second auxiliary weight plate 225B may have the same predetermined weight. In the present embodiment, the weight of the first and second auxiliary weight plates is set at 2.5 pounds (about 1.13 kg), namely one-half the weight of each weight plate 220A, 220B. Referring to FIG. 16 and FIG. 19, in the standby state, the two auxiliary weight plates 225A, 225B are respectively inserted upright in the two positioning recesses 214 of the base 210 with U-shaped openings 227 facing upward, and each of them has its side (outer side) where the lock portion 226 is located, facing away from the center of the base 210. One of the two auxiliary weight plates 225A, 225B located at the same side of the base 210 as the first weight plate 220A may be called the first auxiliary weight plate 225A, and the other one of the two auxiliary weight plates 225A, 225B located at the same side of the base 210 as the second weight plate 220B may be called the second auxiliary weight plate 225B. In order to ensure that the auxiliary weight plates 225A, 225B are inserted into the aforementioned positioning recess 214 with the correct face, a concave portion 228 is formed in the center of the bottom of the outer side of each auxiliary weight plate 225A, 225B (see FIG. 15.), which can match the shape of a convex portion 217 on the outer side of the bottom of the positioning recess 214 when the auxiliary weight plates 225A, 225B are correctly inserted (see FIG. 19 and FIG. 25A).

[0123] Referring to FIG. 16, the handle assembly 202 includes a handle 230 extending along the longitudinal direction, two end seats 240A, 240B respectively connected to the two opposite ends of the handle 230, and two guide tubes (or enclosures) 260 located on two opposite sides of the handle 230 and connected to the two end seats 240A, 240B along the longitudinal direction. In another example, the handle assembly 202 may include at least one enclosure or guide tube 260 connecting the end seats 240A, 240B along the longitudinal direction. In addition, the handle assembly 220 also includes numerous internal components that are not visible from the outside, which will be described in detail later. First, referring to FIG. 20, the basic frame of the handle assembly 202 is composed of several metal components and several of plastic shell components. The metal components may include an axle tube 231, two side plates 241 and the two guide tubes 260. The axle tube 231 extends straight along the longitudinal direction and has a circular cross section. The two side plates 241 are connected to the opposite ends of the axle tube 231 in a vertical manner. Specifically, each side plate 241 is substantially a circular plate, and an engaging block 242 that engages with the end of the axle tube 231 is locked at an approximate central position of its inner side. Each side plate 241 has two square holes 243 located on opposite sides in the width direction. The two guide tubes 260 are located at opposite sides of the axle tube 231 in the width direction, and each guide tube 260 is separated from the axle tube 231 by a predetermined distance and extends straight along the longitudinal direction. The cross sections of the two guide tubes 260 are substantially square or rectangular. Each guide tube 260 has two ends protruding through the respective square holes 243 in the respective side plates 241, and each guide tube 260 is secured to the two side plates 241 by welding around the corresponding square holes 243. Furthermore, each guide tube 260 has two guiding members 261 respectively welded to one side that faces the axle tube 231. The two guiding members 261 are located near the two ends of each guide tube 260 and extend in the height direction. Each guide tube 260 has an aperture 262 at the top of one end thereof.

[0124] The plastic shell components may include two outer shells 244, two upper shells 245 and two lower shells 246. The two outer shells 244 are respectively mounted on the outer sides of the two side plates 241. The two upper shells 245 are respectively mounted on the upper portions of the inner sides of the two side plates 241. The two lower shells 246 are respectively mounted on the lower portions of the inner sides of the two side plates 241. In detail, each outer shell 244 is substantially a circular plate, and the contour of its outer edge matches the side plate 241, and it is abutted and secured to the outer side of the side plate 241. Each outer shell 244 has a through hole 247 corresponding to one square hole 243 of the corresponding side plate 241. The through holes 247 of the two outer shells 244 are located on different sides in the width direction. In other words, the through hole 247 of one outer shell 244 is connected to the opening of one of the guide tubes 260, and the through hole 247 of the other outer shell 244 is connected to the opening of the other guide tube 260. In addition, the outer side surface of each outer shell 244 has a groove 248 extending upward from the bottom edge. The width of the groove 248 in the width direction gradually decreases from bottom to top, and its horizontal cross section is dovetail-shaped, as depicted in FIG. 18A. On the other hand, the upper shell 245 and the lower shell 246 on the inner side of each side plate 241 are aligned up and down, and each uses a plurality of screws (not shown) passing through the side plate 241 to lock with the corresponding outer shell 244, so that the upper shell 245 and the lower shell 246 can be fixed with respect to the side plate 241, and form a chamber 249 on the inner side of the side plate 241, as shown in FIG. 19. Both the apertures 262 and the guiding members 261 of the guide tubes 260 are located in the respective chambers 249. Each upper shell 245 has a window 251 at the center of the top. Each lower shell 246 has a large opening 252 at the inner side and a small opening 253 at the outer side.

[0125] Referring to FIG. 21, the handle 230 is substantially a tubular member with an axial hole whose inner diameter matches the outer diameter of the axle tube 231, so that the handle 230 can be pivotably mounted on the exterior of the axle tube 231, allowing it to rotate in place relative to the axle tube 231 about a rotation axis A1 (as shown in FIGS. 18A-18B or FIG. 19, at the center of the axle tube 231). The handle 230 cannot be moved axially relative to the axle tube 231. The middle section of the handle 230 forms a grip portion 232 that the user can grasp with one hand. To improve grip comfort, a rubber layer can be applied to the grip portion 232. As shown in FIG. 19, the two ends of the handle 230 are located within the two chambers 249. In the present embodiment, the side plate 241, the outer shell 244, the upper shell 245 and the lower shell 246 at each end of the handle 230 together constitute the end seats 240A, 240B, which are used to enclose various mechanisms described below.

[0126] As shown in FIG. 21, each of the two ends of the handle 230 is connected to an indexing disc 233 in a way that cannot rotate relative to each other, so that rotation of the handle 230 about the rotation axis A1 forces the two indexing discs 233 to rotate synchronously. Each indexing disc 233 is enclosed between the respective upper shell 245 and the lower shell 246. Each indexing disc 233 is made up of an annular plate that is coaxial with the axle tube 231 and is pivotably mounted on the axle tube 231 through a central hole 234. Each indexing disc 233 has at least one convex lump 235, such as multiple convex lumps 235. In one example, each indexing disc 233 includes six convex lumps 235 equiangularly disposed on its inner side (around the rotation axis A1), and twelve teeth 236 protruding outward and equidistant around the outer periphery of the outer side of the indexing disc 233. Moreover, each indexing disc 233 has twelve positioning holes 237 equiangularly distributed in a relatively outer circle of the indexing disc 233, and twelve ball sockets 238 equiangularly distributed in a relatively inner circle of the indexing disc 233. The ball sockets 238 correspond to the positions of the positioning holes 237. Each of the teeth 236 is located in the middle position of the angle between the adjacent two positioning holes 237. For example, there are one positioning hole 237 and one ball socket 238 at each of the twelve orientations of the disc (around the rotation axis A1), that is, one o'clock, two o'clock, three o'clock, . . . , and twelve o'clock, while the teeth 236 are located at twelve orientations (hour hand), that is, one-thirty, two-thirty, three-thirty, . . . , and twelve-thirty. On the other hand, referring to FIG. 24A, the six convex lumps 235 are distributed in positions corresponding to six equally spaced positioning holes 237. For example, the convex lumps 235 are only present at six positions: one o'clock, three o'clock, five o'clock, . . . , and eleven o'clock. Furthermore, each indexing disc 233 has twelve weight indicators 239 distributed equally spaced around the outer periphery of the indexing disc 233. The positions of these weight indicators 239 also correspond to the positioning holes 237. The values indicated by these weight indicators 239 are “5”, “10”, “15”, . . . , “50”, “55” and “60”, that is, arithmetic arrangement from the minimum value “5” to the maximum value “60”, and each level is incremented by 5 (in pounds).

[0127] Referring to FIG. 19, each of the indexing discs 233 is separated from the side plate 241 on its outer side by a distance. Each of the two ends of the axle tube 231, which passes through the two indexing discs 233, has a sleeve 254 mounted around it. The outer end of each sleeve 254 is in contact with or very close to the inner side of the corresponding side plate 241, and inner end is in contact with or very close to the outer side of the corresponding indexing disc 233. Therefore, the handle 230 and the two indexing discs 233, which are mounted around the axle tube 231, are incapable of being moved axially, but their rotation is not hindered.

[0128] Referring to FIGS. 18A-18B, FIG. 22 and FIG. 23, the two guide tubes 260 of the handle assembly 202 each accommodates an extension member 265A, 265B. Each extension member 265A, 265B is substantially a straight rod extending along the longitudinal direction, and its cross section is substantially square and the size corresponds to the opening of the guide tube 260. Each extension member 265A, 265B is movable relative to the respective guide tube 260 along the longitudinal direction, including displacement in an outward direction to (at least partially) extend out of the respective guide tube 260, and displacement in an inward direction to (at least partially) retract into the respective guide tube 260. In the present embodiment, when each extension member 265A, 265B is located at an innermost position (e.g., a preset innermost position) (as shown in FIGS. 18A-18B), it will be completely received in the corresponding guide tube 260. Furthermore, the two extension members 265A, 265B received within the two guide tubes 260 are respectively against different sides in the longitudinal direction. Specifically, the outer end of each extension member 265A, 265B is appropriately close to the through hole 247 of the outer shell 244, where the corresponding guide tube 260 is connected, at a predetermined distance, so that each extension member 265A, 265B can pass through the corresponding through hole 247 to exit the respective end seat 240A, 240B. When the extension members 265A, 265B are located at an outermost position (e.g., a preset outermost position) (as shown in FIG. 17), the inner ends of the extension members 265A, 265B are partially supported by the respective guide tubes 260. In other embodiments, the extension members 265A, 265B may not be supported by the guide tubes 260 when in the outermost positions, but may be supported by the corresponding end seat or other components. Each of the guide tubes 260 may be equivalent to an enclosure, which is located outside the handle 230 and separated by a sufficient distance that does not hinder the user from gripping the handle 230.

[0129] For the convenience of the following explanation, the two ends of the handle 230 may be referred to as the first end and the second end, respectively. Correspondingly, the end seat connected to the first end of the handle 230 is referred to as the first end seat 240A, and the end seat connected to the second end of the handle 230 is referred to as the second end seat 240B. In addition, the extension member that can pass through the through hole 247 of the first end seat 240A to the outside is referred to as the first extension member 265A, and the extension member that can pass through the through hole 247 of the second end seat 240B to the outside is referred to as the second extension member 265B. It should be noted that, just like the first and second weight plates 220A, 220B and the first and second auxiliary weight plates 225A, 225B mentioned above, the addition of “first” or “second” at the beginning of the name (and the addition of “A” or “B” at the end of the symbol) only indicates that they are located on different sides, and there is no substantial difference in their structure. In fact, based on the symmetrical structure of the handle assembly 202, when the adjustable dumbbell system 200 is used, it is not limited to a specific end of the handle assembly 202 corresponding to a specific end of the base 210. In short, the handle assembly 202 that is removed from the base 210 as shown in FIG. 16 can be put back in the same way when it is horizontally rotated 180 degrees.

[0130] By means of a linkage mechanism, the first extension member 265A and the second extension member 265B are linked to each other, so that the first extension member 265A and the second extension member 265B can be operated to move in opposite directions in the longitudinal direction. In other words, the symmetrically arranged first extension member 265A and the second extension member 265B could be moved simultaneously in either the outward or inward direction. Referring to FIG. 18B, FIG. 22 and FIG. 23, in order to constitute the linkage mechanism, the first end seat 240A is provided with a first transmission mechanism 270A (e.g., a gear transmission mechanism) that is operatively connected to the first extension member 265A, which can convert a rotational movement into a linear movement of the first extension member 265A in the longitudinal direction. Symmetrically, the second end seat 240B is provided with a second transmission mechanism 270B that is operatively connected to the second extension member 265B, which can convert a rotational movement into a linear movement of the second extension member 265B in the longitudinal direction. The rotational movement of the first transmission mechanism 270A is linked to the rotational movement of the second transmission mechanism 270B. Thus, the first extension member 265A can be interconnected with the second extension member 265B via rotational transmission means.

[0131] The first extension member 265A may be provided with a first rack 266A extending in the longitudinal direction, and the first transmission mechanism 270A may have at least one rotatable first gear, and one first gear is engaged with the first rack 266A, so that rotation of the first gear drives the first extension member 265A to move linearly. Similarly, the second extension member 265B may be provided with a second rack 266B extending in the longitudinal direction, and the second transmission mechanism 270B may have at least one rotatable second gear, and one second gear is engaged with the second rack 266B, so that rotation of the second gear drives the second extension member 265B to move linearly. Furthermore, considering that the two transmission mechanisms 270A, 270B are located at opposite ends of the handle 230 and spaced in a distance, in order to link the gear rotation movements of the first transmission mechanism 270A and the second transmission mechanism 270B, one of the first gears of the first transmission mechanism 270A and one of the second gears of the second transmission mechanism 270B may be coaxially connected, with their axes corresponding to the longitudinal direction and passing through the inside of the handle 230.

[0132] In the present embodiment, the outer side surface of each indexing disc 233 has an integrated or fixed a ring gear 271 (a bevel gear) surrounding the axle tube 231, and a pinion gear 272 (a bevel gear as well) is arranged at one specific side edge of the ring gear 271 to mesh with it, in such a manner that the axis of the pinion gear 272 is perpendicular to the axis of the ring gear 271. In this embodiment, the axis (hereinafter referred to as driven axis) A2 of the pinion gear 272 corresponds to the width direction. Each pinion gear 272 is pivotally mounted on a seat block 255 on the inner side surface of the respective side plate 241 in a manner that can rotate in place, and is coaxially fixed with a spur gear 273. Each spur gear 273 meshes with the rack 266A, 266B of the corresponding extension member 265A, 265B through the aperture 262 of the corresponding guide tube 260. Thus, when the handle 230 and the two indexing discs 233 rotate about the rotation axis A1, the two ring gears 271 will drive the respective pinion gears 272 and the spur gears 273 to rotate about the respective driven axes A2, thereby driving the first extension member 265A and the second extension member 265B to move along the longitudinal direction respectively.

[0133] As shown in FIGS. 18A-18B, the two pinion gears 272 that mesh with the respective ring gears 271 are arranged on the same side, so that no matter what rotation direction of the two ring gears 271 that are rotated synchronously, the rotation directions of the two pinion gears 272 with parallel axes are always opposite. Thus, when the handle 230 and the two indexing discs 233 rotate in a forward rotation direction F shown in FIG. 22 and FIG. 23, the first extension member 265A and the second extension member 265B will move outward simultaneously. In contrast, when the handle 230 and the two indexing discs 233 rotate in a reverse rotation direction (opposite to the forward rotation direction F), the first extension member 265A and the second extension member 265B will move inward simultaneously. That is, the two extension members 265A, 265B move in opposite directions in the longitudinal direction.

[0134] In accordance with one gear ratio, each ring gear 271 can rotate less than one circle (e.g., 330 degrees) to drive the respective extension member 265A, 265B from the innermost position to the outermost position or from the outermost position to the innermost position. When the spur gear 273 is operated to drive the rack 266A, 266B outward to the end where the spur gear 273 is stuck on a terminal end near the inner end of the rack 266A, 266B, the extension member 265A, 265B is located at the outermost position accordingly, and the handle 230 can no longer be rotated in the forward rotation direction. In contrast, when the spur gear 273 is operated to drive the rack 266A, 266B inward to the end where the spur gear 273 is stuck on a terminal end near the outer end of the rack 266A, 266B, the extension member 265A, 265B is located at the innermost position accordingly, and the handle 230 can no longer be rotated in the reverse rotation direction. Based on the symmetrical structure of the handle assembly 202, the first extension member 265A and the second extension member 265B will be located at their respective innermost positions and the outermost positions at the same time. Moreover, since the rates of the linear displacement of the two extension members 265A, 265B are identical, the protruding lengths out of the respective end seats 240A, 240B will also be identical.

[0135] In the above structures, the ring gear 271, the pinion gear 272 and the spur gear 273 disposed inside the first end seat 240A can be referred to as the first gear of the first transmission mechanism 270A. The ring gear 271, the pinion gear 272 and the spur gear 273 disposed inside the second end seat 240B can be referred to as the second gear of the second transmission mechanism 270B. The two ring gears 271 are arranged at the first end and the second end of the handle 230 respectively. The two ring gears 271 are coaxially connected, with their axes (which overlap the rotation axis A1) corresponding to the longitudinal direction and passing through the inside of the handle 230. Rotation of the handle 230 can drive the two ring gears 271 to rotate synchronously. In other embodiments, the first transmission mechanism has only one first gear, and the second transmission mechanism has only one second gear. The first gear and the second gear are coaxially connected and mesh with the first rack of the first extension member and the second rack of the second extension member respectively (for example, each gear may be a worm gear with a large diameter), which can also convert rotation movement into linear movement. Of course, the present invention can also adopt various transmission mechanisms that can convert rotation movement into linear movement.

[0136] In the present embodiment, through the selection of components and size settings in the design, the weight of the handle assembly 202 is about 5 pounds, including the handle 230, end seats 240A, 240B, guide tubes 260, extension members 265A, 265B, transmission mechanisms 270A, 270B, etc., and the total weight of several internal components not mentioned above.

[0137] Referring to FIG. 11 to FIG. 13, in the standby state, the handle assembly 202 is aligned centrally between the two ends of the base 210 in the longitudinal direction. Specifically, the handle assembly 202 is positioned between the first weight plates 220A and the second weight plates 220B. The first end and the second end of the handle 230 correspond to the directions of the first weight plates 220A and the second weight plates 220B, respectively. The outer side surfaces of the first end seat 240A and the second end seat 240B are respectively abutted against the inner side surfaces of the innermost first weight plate 220A and the innermost second weight plate 220B. In the standby state, the weight plates, the auxiliary weight plate and the end seat of the handle assembly located on any half of the base 210 can be called the first weight plates, the first auxiliary weight plate and the first end seat, respectively, and the weight plates, the auxiliary weight plate and the end seat of the handle assembly located on the other half of the base 210 can be called the second weight plates, the second auxiliary weight plate and the second end seat, respectively. The grooves 248 on the outer side surfaces of the first end seat 240A and the second end seat 240B are respectively engaged with the aforementioned ridges 222 on the inner side surfaces of the first weight plate 220A and the second weight plate 220B (see FIGS. 18A-18B). When the weight plates 220A, 220B are correctly attached to the respective end seats 240A, 240B, the through hole 247 on the outer side of the first end seat 240A will be aligned with the recess 223 of the first weight plate 220A, so that the movement path (extension axis) of the first extension member 265A is aligned with the first channel 224A. Symmetrically, the through hole 247 on the outer side of the second end seat 240B may be aligned with the recess 223 of the second weight plate 220B, so that the movement path of the second extension member 265B is aligned with the second channel 224B. At the same time, as shown in FIGS. 18 and 19, the first auxiliary weight plate 225A and the second auxiliary weight plate 225B, whose bottoms are respectively inserted into the two positioning recesses 214 of the base 210, and at least their upper halves are respectively located in the chambers 249 of the first end seat 240A and the second end seat 240B, and are respectively located on the inner sides of the respective indexing discs 233, with the upward U-shaped openings 227 accommodating the corresponding ends of the handle 230. The two opposite sides of each auxiliary weight plate 255A, 255B in the width direction can be embedded in the two opposite guiding members 261 in the corresponding chamber 249.

[0138] As shown in FIG. 16, the handle assembly 202 can be moved upward along the extension direction of the grooves 248 and the guiding members 261 to leave the base 210 alone. Similarly, the handle assembly 202 that leaves the base 210 can have its grooves 248 on the two ends align and move downward to engage the ridges 222 of the innermost two weight plates 220A, 220B (at the same time, the guiding members 261 will accommodate the two sides of the two auxiliary weight plates 225A, 225B) to return to the preset position in the standby state. During this process, the first auxiliary weight plate 225A and the second auxiliary weight plate 225B respectively enter or exit the chambers 249 of the first and second end seats 240A, 240B through the large openings 252 (see FIG. 15) at the bottoms of the first and second end seats 240A, 240B.

[0139] FIG. 24A is a cross-sectional view of the first end seat 240A, with the internal conformation of the second end seat 240B being the same. As shown in FIG. 24A, in the standby state, when the first and second extension members 265A, 265B are in the innermost positions, the twelve positioning holes 237 on each indexing disc 233 will be located at twelve positions (centered on the aforementioned rotation axis A1) of one o'clock, two o'clock, three o'clock, . . . , and twelve o'clock, and one specific positioning hole 237 is located directly below the rotation axis A1 (six o'clock position), and the six convex lumps 235 on each indexing disc 233 are located at one o'clock, three o'clock, five o'clock, seven o'clock, nine o'clock and eleven o'clock, respectively, avoiding the position directly below the rotation axis A1. At this time, the weight indicator 239 located at the top (12 o'clock position) on the circumference of each indexing disc 233 indicates the minimum value of “5”. The user can see the weight indicator 239 located at the top of the indexing disc 233 through the window 251 on the top of the first end seat 240A and the second end seat 240B. When the user rotates the handle 230 and the two indexing discs 233 in the forward rotation direction from the current angular position (hereinafter referred to as the starting angular position), the weight indicators 239 on the circumference of each indexing disc 233 will pass under the window 251 in the order of “10”, “15”, “20”, etc. In this embodiment, each time the handle 230 is rotated 30 degrees (as a unit angle), the indexing disc 233 rotates 30 degrees accordingly so that the next weight indicator 239 in accordance with the rotation direction is positioned on the top, and the positioning hole 237 is changed to the next, for example, changed from the state shown in FIG. 24A to the state shown in FIG. 24B (Note: the positions of the convex lumps 235 in the two figures differ by 30 degrees), or vice versa. On the other hand, when the handle 230 rotates one unit angle, both the first extension member 265A and the second extension member 265B will move a unit distance along the longitudinal direction, respectively. The unit distance is approximately equal to half the thickness of each weight plate 220A, 220B in the longitudinal direction, that is, half the length of the recess 223 that passes through the inner and outer sides of the weight plate in the longitudinal direction.

[0140] When the first extension member 265A and the second extension member 265B are located at the innermost position, the distance between the outer end face of each extension member 265A, 265B and the outer side surface of the corresponding end seat 240A, 240B is slightly greater than the unit distance. After the handle 230 is rotated by one unit angle (30 degrees) in the forward rotation direction from the starting angular position, the angle of each indexing disc 233 relative to the end seat 240A, 240B is shown in FIG. 24B. At this time, the weight indicator 239 positioned on the top indicates a value of “10”, and the outer end face of each extension member 265A, 265B is close to the outer side surface of the corresponding end seat 240A, 240B. If the handle 230 is rotated by another unit angle in the forward rotation direction (equal to 60 degrees of cumulative forward rotation), the angle of each indexing disc 233 relative to the end seat 240A, 240B will be similar to the state shown in FIG. 24A. At this time, the weight indicator 239 on the top indicates a value of “15”, and the outer end of each extension member 265A, 265B is protruded from the respective end seat 240A, 240B via the corresponding through hole 247, and extended into the recess 223 of the innermost first weight plate 240A or the innermost second weight plate 240B, with the outer end face being approximately located at the middle of the recess 223. If the handle 230 is further rotated by another unit angle in the forward rotation direction (equal to 90 degrees of cumulative forward rotation), the angle of each indexing disc 233 relative to the end seat 240A, 240B will be similar to the state shown in FIG. 24B again. At this time, the weight indicator 239 on the top indicates a value of “20”, and the outer end face of each extension member 265A, 265B is close to the outer side surface of the innermost first weight plate 220A or the innermost second weight plate 220B. The rest can be deduced by analogy. Finally, if the handle 230 is rotated 330 degrees in the forward rotation direction from the starting angular position (i.e., 11 times the unit angle), the angle of each indexing disc 233 relative to the end seat 240A, 240B will be similar to the state shown in FIG. 24B. At this time, the weight indicator 239 positioned on the top is marked as the maximum value “60”, and the outer end face of each extension member 265A, 265B is close to the outer side surface of the outermost first weight plate 220A or the outermost of the second weight plate 220B, reaching the outermost position of the preset movement range.

[0141] In summary, when the handle 230 is at the starting angular position, or the angular position differs from the starting angular position by an even multiple of the unit angle (equal to a cumulative forward rotation of 60, 120, 180, 240 or 300 degrees), the angle of each indexing disc 233 relative to the end seat 240A, 240B is shown as FIG. 24A. Besides, the convex lumps 235 of each indexing disc 233 avoid the position directly under the lock portion 226 of the auxiliary weight plate 225A, 225B. When the angular position of the handle 230 differs from the starting angular position by an odd multiple of the unit angle (equal to a cumulative forward rotation of 30, 90, 150, 210, 270 or 330 degrees), the angle of each indexing disc 233 relative to the end seat 240A, 240B is shown as FIG. 24B. Besides, one of the convex lumps 235 of each indexing disc 233 is blocked directly under the lock portion 226 of the corresponding auxiliary weight plate 225A, 225B, and the top surface of the convex lump 235 is abutted against the bottom surface of the lock portion 226.

[0142] In general, in the standby state, the handle 230 of the handle assembly 202 (together with the indexing discs 233 and the ring gears 271) can rotate forwardly or reversely within a preset angle range (e.g., 330 degrees) relative to the end seats 240A, 240B that are anchored on the base 210. Each time the handle 230 is rotated in the forward rotation direction by a predetermined angle (e.g., the aforementioned unit angle), the first extension member 265A can be moved in the direction away from the second end seat 240B by a predetermined distance (e.g., the aforementioned unit distance), and the second extension member 265B can be moved in the direction away from the first end seat 240A by the predetermined distance simultaneously. In contrast, each time the handle 230 is rotated in the reverse rotation direction by the predetermined angle, the first extension member 265A can be driven to move in the direction close to the second end seat 240B by the predetermined distance, and the second extension member 265B can be moved in the direction close to the first end seat 240A by the predetermined distance simultaneously. In the present embodiment, the handle 230 and the indexing discs 233 can be positioned at one of twelve predetermined angular positions (including the starting angular position) relative to the end seats 240A, 240B. That is, when one of the positioning holes 237 of the indexing disc 233 is directly below the rotation axis A1, the handle 230 and the indexing disc 233 are positioned at one of the predetermined angular positions. Any two adjacent predetermined angular positions are 30 degrees apart.

[0143] Referring to FIG. 25A, a steel ball 280 is disposed in each end seat 240A, 240B, on the outer side of the corresponding indexing disc 233. The steel ball 280 is elastically biased by a spring in an inward direction. When the indexing disc 233 is located at any predetermined angular position, the inner half of the steel ball 280 will sink into a corresponding one of the predetermined ball socket 238 on the respective indexing disc 233 (in this embodiment, the ball socket 238 is located directly below the rotation axis A1). During the indexing disc 233 rotating from one of the predetermined angular positions to the next one, as shown in FIG. 25B, the steel ball 280 will be squeezed out of the ball socket 238 and abut against the flat part of the outer side surface of the indexing disc 233 until it “clicks” and sinks into the next ball socket 238. In this way, when the user rotates the handle 230, there will be a pause or calibration effect at the predetermined angular positions, creating the sensation of stepwise adjustment.

[0144] As shown in FIGS. 25A and 25B, when the handle assembly 202 is placed on the base 210, the two hooks 216 of the base 210 respectively extend into the interiors of the end seats from the small openings 253 (see FIG. 15) at the bottoms of the two end seats 240A, 240B, such that each hook 216 is located at the bottom of the outer side of the respective indexing disc 233, and the horizontal extension part of the top of each hook 216 that bends inward is slightly higher than the bottom edge of the circumference of the respective indexing disc 233. As shown in FIGS. 24A and 24B, when the indexing disc 233 is at any predetermined angular position, the hook 216 is between the two adjacent teeth 236 at the bottom of the circumference of the indexing disc 233 (e.g., located at 5:30 and 6:30 positions). Therefore, as long as the handle 230 is at one of the twelve predetermined angular positions, the handle assembly 202 can be smoothly lifted up from the base 210 and put back onto the base 210 without interference from the hook 216. However, if the handle 230 is not in any predetermined angular position (for example, the indexing disc 233 is rotated 15 degrees clockwise or counterclockwise from the angle shown in FIG. 24A or FIG. 24B), one of the teeth 236 (all or part) at the bottom of each indexing disc 233 will be located below the horizontal extension part of the corresponding hook 216, so that the handle assembly 202 cannot be lifted up from the base 210.

[0145] Referring to FIG. 25A, inside each end seat 240A, 240B, there is a locking member 290 that can slide slightly along the longitudinal direction and a releasing member 295 that can slide slightly along the height direction, at the bottom of the outer side of the respective indexing disc 233. The releasing member 295 is located below the locking member 290 and is close to the small opening 253 at the bottom of the end seat 240A, 240B. The locking member 290 is elastically biased by a compression spring 291 in an inward direction. The locking member 290 and the releasing member 295 are abutted against each other by their incline planes, such that movement of the locking member 290 in the inward direction pushes the releasing member 295 to move downward, while upward movement of the releasing member 295 pushes the locking member 290 to move in the outward direction. The locking member 290 has a latch 292 extending in the longitudinal direction on its inner side. When the indexing disc 233 is located at any predetermined angular position, the latch 292 of the locking member 290 is substantially coaxial with the positioning hole 237 of the indexing disc 233 located below the rotation axis A1. When the handle assembly 20 is rested on the base 210, the two bumps 215 of the base 210 will enter the interiors of the end seats 240A, 240B through the small openings 253 at the bottoms of the two end seats 240A, 240B respectively, so that each releasing member 295 will be pushed upward by the corresponding bump 215 to a higher position as shown in FIG. 25A. In addition, each locking member 290 is pushed to a relatively outer position within its movable range by the corresponding releasing member 295 (compressing the compression spring 291), so that the latch 292 is pulled out of the positioning hole 237 of the respective indexing disc 233 and does not hinder the rotation of the indexing disc 233 and the handle 230. When the handle assembly 202 is moved upward from the base 210, the bumps 215 will be relatively downward, and each locking member 290 (which is pushed or biased by the compression spring 291) will immediately push the corresponding releasing member 295 downward to a lower position as shown in FIG. 28. In addition, each locking member 290 will move to a relatively inner position within its movable range, so that the latch 292 is inserted in the specific positioning hole 237 of the respective indexing disc 233. Therefore, the indexing discs 233 and the handle 230 can be locked at the current angular position.

[0146] In summary, the hooks 216 and the bumps 215 on the base 210, and the teeth 236 and the positioning holes 237 on each indexing disc 233, and locking member 290, the releasing member 295 and the compression spring 291 of each end seat 240A, 240B, and so on, together constitute a locking mechanism with dual functions. In short, when the handle assembly 202 is placed on the base 210, the handle 230 is allowed to rotate freely within a preset angle range (so that the angle of the two indexing discs 233 and the positions of the two extension members 265A, 265B can be changed accordingly), but the handle assembly 202 can only leave the base 210 when the handle 230 is located in the predetermined angular position. As soon as the handle assembly 202 leaves or disengages the base 210, the handle 230 will be locked in the current angular position, preventing the angle of the two indexing discs 233 and the positions of the two extension members 265A, 265B from being changed until the handle assembly 202 is placed back into the base 210 again.

[0147] With the adjustable dumbbell system 200 provided in this embodiment, the user can rotate the handle 230 to selectively engage the first and second weight plates 220A, 220B and / or the first and second auxiliary weight plates 225A, 225B on the handle assembly 202 so as to select or adjust the dumbbell weight for weight training. The working principle of selectively engaging of the weight plates 220A, 220B is basically the same as that of the previous embodiment. That is, rotating the handle 230 will drive the first and second extension members 265A, 265B to move simultaneously in the outward or inward direction via the aforementioned first and second transmission mechanism 270A, 270B. Specifically, the first extension member 265A can extend from the corresponding guide tube 260 and the first end seat 240A in the direction away from the second end seat 240B, and extend outward into the recesses 223 of the first weight plates 220A in sequence to engage one or more first weight plates 220A. In contrast, the second extension member 265B can extend from the corresponding guide tube 260 and the second end seat 240B in the direction away from the first end seat 240A, and extend outward into the recesses 223 of the second weight plates 220B in sequence to engage one or more second weight plates 220B. For example, as shown in FIG. 26, in the state that the outer ends of the first extension member 265A and the second extension member 265B respectively extended into the recesses 223 of the second one of the first weight plates 220A and the second one of the second weight plates 220B (counted from inside to outside), when the user grasps the handle assembly 202 and moves it upward away from the base 210, the first extension member 265A and the second extension member 265B will hold up the inner two first weight plates 220A and the inner two second weight plates 220B respectively (the remaining weight plates 220A, 220B remain on the base 210). Moreover, since the possible displacement direction (i.e., displacement from top to bottom) of each weight plate 220A, 220B relative to the other weight plate 220A, 220B or the handle assembly 202 on its inner side is blocked by the extension member 265A, 265B, such that the lifted weight plates 220A, 220B can remain in place at both ends of the handle assembly 202 without falling off. In the present embodiment, when each extension member 265A, 265B is operated to move outward to engage one more weight plate 220A, 220B, the weight of the dumbbell 204 will increase by 10 pounds (that is, the weight of a pair of weight plates 265A and 265).

[0148] As mentioned above, in the present embodiment, the handle 230 is rotated and positioned stepwise at a unit angle of 30 degrees. Correspondingly, the extension members 265A, 265B extend or retract stepwise or steplessly with half the thickness of each weight plate 220A, 220B as a unit distance. Therefore, as the handle 230 is positioned at different predetermined angular positions, the outer end of each extension member 265A, 265B may sometimes extend close to the outer end of the recess 223, or sometimes only extend to the middle of the recess 223. However, based on the appropriate size setting, even if the extension members 265A, 265B are only extended into half the thickness of a certain weight plate 220A, 220B (even slightly less), the weight plates 220A, 220B can be lifted upward and can be blocked from detaching in the height direction. For example, as shown in FIG. 29, when the outer ends of the first extension member 265A and the second extension member 265B are respectively located in the middle positions of the recesses 223 of the third one of the first weight plates 220A and the third one of the second weight plates 220B (counted from inside to outside), the handle assembly 202 detached from the base 210 will engage three pairs of weight plates 220A, 220B. Comparing FIG. 26 and FIG. 29, the extension members 265A, 265B can be operated to move outward by one unit distance from the position shown in FIG. 26 to the position shown in FIG. 29, so that the weight plates 220A, 220B held up by the extension members 265A, 265B can be increased from two pairs to three pairs. However, the extension members 265A, 265B can still only hold the same three pairs of weight plates 220A, 220B when they are operated to move outward by a further one unit distance (in the standby state). In summary, when the handle 230 is rotated from one predetermined angular position to another predetermined angular position in the forward rotation direction by the unit angle twice (i.e., 60 degrees), an additional first weight plate 220A and second weight plate 220B will be added to the handle assembly 202. When the handle 230 is rotated from one predetermined angular position to another predetermined angular position in the reverse rotation direction by the unit angle twice, the handle assembly 202 will disengage one first weight plate 220A and one second weight plate 220B.

[0149] On the other hand, as mentioned above, when the handle 230 is located in the first, third, fifth, . . . , or eleventh predetermined angular position of the twelve predetermined angular positions (starting from the starting angular position), the angle of each indexing disc 233 is shown as FIG. 24A, and the convex lumps 235 of each indexing disc 233 avoid the position directly below the lock portion 226 of the auxiliary weight plate 225A, 225B. When the handle 230 is located in the second, fourth, sixth, . . . , or twelfth predetermined angular positions, the angle of each indexing disc 233 is shown as FIG. 24B, and one of the convex lumps 235 of each indexing disc 233 is blocked directly under the lock portion 226 of the corresponding auxiliary weight plate 225A, 225B. In the state shown in FIG. 24A, the handle assembly 202 does not hook the two auxiliary weight plates 225A, 225B when it moves upward away from the base 210. Therefore, after the handle assembly 202 leaves or disengages the base 210, the auxiliary weight plates 225A, 225B are still in their preset positions on the base 210. In the state shown in FIG. 24B, when the handle assembly 202 is lifted upwardly from the base 210, since each indexing disc 233 has one convex lump 235 blocked directly under the lock portion 226 of the corresponding auxiliary weight plate 225A, 225B, the two auxiliary weight plates 225A, 225B will be lifted upward respectively (see FIG. 27 and FIG. 28). Moreover, since the auxiliary weight plates 225A, 225B cannot move downward or in other directions with respect to the handle assembly 202 at this time (the upward movement is blocked by the handle 230, and the movements in the width and longitudinal directions are retained by the guiding members 261), the two auxiliary weight plates 225A, 225B that are lifted can be kept engaged at the two ends of the handle assembly 202 (inside the first and second end seats 240A, 240B) without falling off. Thus, when the handle 230 is rotated from one predetermined angular position to another predetermined angular position by one unit angle, the handle assembly 202 can be changed from the state with the two auxiliary weight plates 225A, 225B to the state without the two auxiliary weight plates 225A, 225B, or vice versa. In this embodiment, mounting the two auxiliary weight plates 225A, 225B increases the weight of the dumbbell 204 by 5 pounds.

[0150] Referring to the auxiliary weight plates 220A, 220B mentioned above, in the standby state, the user is able to read the weight indicator 239 through the window 251 on the top of each end seat 240A, 240B of the handle assembly 202 to know the current weight of the dumbbell. For example, if the value below the window 251 is “5”, it means that the handle assembly 202 is not engaged with any weight plate 220A, 220B or auxiliary weight plate 225A, 225B. As shown in FIG. 16, the user can individually grasp the handle assembly 202 from the base 210 and perform weight training with only the 5-pound handle assembly 202 (i.e., the lightest dumbbell 204). If the user wants to change the weight of the dumbbell 204, the handle 230 can be rotated to an appropriate predetermined angular position in the standby state, namely rotating the handle 230 to change the value below the window 251 to the target weight, so that the handle assembly 202 can be mounted with an appropriate number of weight plates 220A, 220B and / or auxiliary weight plates 225A, 225B to from a dumbbell 204 with the target weight. For example, if the handle 230 is rotated from the aforementioned starting angular position (corresponding to the lightest dumbbell) by one unit angle in the forward rotation direction to the second predetermined angular position, the handle assembly 202 will engage the two auxiliary weight plates 225A, 225B, and the value below the window 251 will become “10”, which is equal to the sum of weights of the handle assembly 202 and the two auxiliary weight plates 225A, 225B. If the handle 230 is rotated to the third predetermined angular position, the handle assembly 202 will disengage the two auxiliary weight plates 225A, 225B, and the innermost pair of weight plates 220A, 220B will be mounted, and the value below the window 251 will become “15”, which is equal to the sum of the weights of the handle assembly 202 and a pair of weight plates 220A, 220B. If the handle 230 is rotated to the fourth predetermined angular position, the handle assembly 202 will engage the innermost pair of the weight plates 220A, 220B and the two auxiliary weight plates 225A, 225B simultaneously, and the value below the window 251 will become “20”, which is equal to the sum of the weights of the handle assembly 202, a pair of weight plates 220A, 220B and the two auxiliary weight plates 225A, 225B. The rest can be deduced accordingly. Finally, if the handle 230 is rotated to the twelfth predetermined angular position, the handle assembly 202 will engage all the weight plates 220A, 220B and the two auxiliary weight plates 225A, 225B simultaneously, and the value below the window 251 will become “60”, which is equal to the sum of the weights of the handle assembly 202, five pairs of weight plates 220A, 220B and the two auxiliary weight plates 225A, 225B, forming the heaviest dumbbell 204 in the adjustable range, as shown in FIG. 17.

[0151] In short, the adjustable dumbbell system 200 provided in the present embodiment allows the user to select or adjust the most suitable dumbbell weight from the twelve weight options, which range from the lightest 5 pounds to the heaviest 60 pounds in 5-pound increments according to the personal physical ability and weight training content.

[0152] In this manner, the handle 230 in the handle assembly 202 forms a weight selection portion that can be rotated by the user to select or adjust the weight of the dumbbell. However, the weight selection portion is not limited to the entire handle. For example, in other embodiments, a portion of the handle can form the weight selection portion such as an annular component located at one or both ends of the outer side of the grip portion, or a knob or dial can be provided on at least one of the end seats of the handle assembly as the weight selection portion. The rotation axis of the weight selection portion may be coaxial, parallel or non-parallel (e.g., perpendicular) to the rotation axis A1 of the two indexing discs 233 or the two ring gears 271, and a rotation transmission mechanism for changing the rotational speed and / or direction may be mounted between the weight selection portion and the indexing discs or the ring gears. In summary, in various preferred embodiments, each time the weight selection portion is rotated in a forward rotation direction by a predetermined angle (e.g., the aforementioned unit angle), the first extension member 265A can be driven to move a predetermined distance (e.g., the aforementioned unit distance) in a direction away from the second end seat 240B, while the second extension member 265B can be driven to move the predetermined distance in a direction away from the first end seat 240A at the same time. In contrast, each time the weight selection portion is rotated in a reverse direction by the predetermined angle, the first extension member 265A can be driven to move the predetermined distance in a direction close to the second end seat 240B, while the second extension member 265B can be driven to move the predetermined distance in the direction close to the first end seat 240A at the same time.

[0153] In addition, the indexing disc 233 in the first end seat 240A forms a first engaging member, and the indexing disc 233 in the second end seat 240B forms a second engaging member. The first engaging member and the second engaging member can be driven by rotation of the weight selection portion. When the weight selection portion is located at specific predetermined angular positions (e.g., the state shown in FIG. 24A, the convex lumps 235 avoid the position directly under the lock portion 226), the first engaging member and the second engaging member do not engage the first auxiliary weight plate 225A and the second auxiliary weight plate 225B. When the weight selection portion is located at other predetermined angular positions (e.g., the state shown in FIG. 24A, one of the convex lumps 235 is located directly under the lock portion 226), the first engaging member and the second engaging member respectively engage the first auxiliary weight plate 225A and the second auxiliary weight plate 225B, so that the handle assembly 202 can be operated to selective engage the first auxiliary weight plate 225A and the second auxiliary weight plate 225B.

[0154] Under this arrangement, the adjustable dumbbell system 200 allows the user to perform weight selection in a simple, quick and reliable manner, so as to obtain a dumbbell with the desired weight and identical weights on both ends. Furthermore, in accordance with the second embodiment, the adjustable dumbbell system 200 allows the user to make fine adjustments to the weight of the dumbbell, so as to better suit their personal conditions and actual needs. In addition, the adjustable dumbbell system can use fewer weight components under the same maximum total weight level, providing more adjustment levels and a smaller adjustment range.

[0155] FIG. 30 shows an adjustable dumbbell system 300 in accordance with a third embodiment of the present invention. Similar to the previous embodiment, the adjustable dumbbell system 300 includes a base 310, a plurality of first weight plates 320A, a plurality of second weight plates 320B, a first auxiliary weight plate and a second auxiliary weight plate (hidden in the figure), and a handle assembly 302. FIG. 30 depicts that the handle assembly 302 mounting all weight plates 320A, 320B and auxiliary weight plates, forming the heaviest dumbbell 304.

[0156] The handle assembly 302 also includes a handle 330, a first end seat 340A and a second end seat 340B respectively connected to the two opposite ends of the handle 330, and two guide tubes 360 connected to the two end seats 340A, 340B along the longitudinal direction, and a first extension member 365A and a second extension member 365B respectively (at least partially) accommodated in the two guide tubes 360. Referring to FIG. 31, the operation principle is the same as that of the precious embodiment. Rotating the handle 330 will drive a ring gear 371 inside each end seat 340A, 340B to rotate synchronously, causing a pinion gear 372 that is engaged with the ring gear 371 to rotate at a faster speed. Each pinion gear 372 is coaxially fixed to a spur gear 373. Each spur gear 373 meshes with a first rack 366A of the first extension member 365A or a second rack of the second extension member 365B. Thus, forward rotation of the handle 330 will drive the first extension member 365A and the second extension member 365B to extend outward, and reverse rotation of the handle 330 will drive the first extension member 365A and the second extension member 365B to retract inward. In the present embodiment, the cross section of each extension member 365A, 365B is approximately a rectangle, and the cross-sectional shape of the recess 323 in each weight plate 320A, 320B (for receiving the extension member) corresponds to it. In addition, the recess 323 is a through hole that passes through the weight plate 320A, 320B, not touching the outer edge of the weight plate 320A, 320B.

[0157] The third embodiment is similar to the second embodiment, except the locking mechanism for locking the handle 330 (or weight selection portion) and the two extension members 365A, 365B. Referring to FIG. 31 and FIG. 32A, in this embodiment, the portions of the base 310 corresponding to the first end seat 340A and the second end seat 340B, each is provided with a bump 315 and a vertical piece 318. The vertical piece 318 has a slot 319. Each extension member 365A, 365B has a plurality of positioning holes 367 spaced equidistantly along the longitudinal direction, and a plurality of ball sockets 368 spaced equidistantly along the longitudinal direction. The number of the positioning holes 367 is the same as the number of the predetermined angular positions of the weight selection portion, such as twelve. As shown in FIG. 32A, inside each end seat 340A, 340B, there is a locking member 390 that can slide slightly in the width direction, and a releasing member 395 that can slide slightly in the height direction. The locking member 390 and the releasing member 395 are abutted against each other by their incline planes, so that if the locking member 390 moves in the outward direction (referring to the direction toward the corresponding extension member 365A, 365B, such as left direction in FIG. 32A), it will push the releasing member 395 downward, and if the releasing member 395 moves upward, it will push the locking member 390 to move in the inward direction (as the right direction in FIG. 32A). The locking member 390 has a latch 392 extending in the width direction, which is elastically biased by a compression spring 391 in the outward direction. When the handle 330 is located at any predetermined angular position, the latch 392 of each locking member 390 is substantially coaxial with one positioning hole 367 on the corresponding extension member 365A, 365B.

[0158] As shown in FIG. 32A, when the handle assembly 302 is placed on the base 310, the two bumps 315 will enter the interiors of the end seats 340A, 340B through the openings 353 at the bottoms of the two end seats 340A, 340B respectively, so that each releasing member 395 will be pushed upward by the corresponding bump 315 to a higher position, and each locking member 390 will be pushed to a relatively inner position within its movable range by the corresponding releasing member 395 (compressing the compression spring 391), so that the latch 392 is pulled out of the positioning hole 367 of the respective extension member 365A, 365B and does not hinder the rotation of the extension member 365A, 365B and the handle 330. As shown in FIG. 32B, when the handle assembly 302 is moved upward from the base 210, the bumps 315 will be relatively downward, and each locking member 390 (which is pushed or biased by the compression spring 391) will immediately push the corresponding releasing member 395 downward to a lower position, and then each locking member 390 will move to a relatively outer position within its movable range, so that the latch 392 can be inserted into a specific positioning hole 367 of the respective extension member 365A, 365B. Therefore, the two extension members 365A, 365B and the handle 330 can be locked.

[0159] Referring to FIG. 32A, when the handle assembly 302 is placed on the base 310, the two vertical pieces 318 on the base 310 respectively extend into the interiors of the two end seats 340A, 340B. At the same time, the locking member 390 pushed inward (to the right in FIG. 32A) by the releasing member 395 causes the inner end of the latch 392 to pass through the slot 319 of the corresponding vertical piece 318. If the handle 330 is not in any predetermined angular position, so that each extension member 365A, 365B has no positioning hole 367 aligned with the latch 392, then, the latch 392 cannot move outward (to the left). That is, the inner end of the latch 392 cannot be pulled out of the slot 319 of the respective vertical piece 318, such that the handle assembly 302 cannot be lifted from the base 310.

[0160] A steel ball (not shown) may be disposed at an appropriate position inside each end seat 340A, 340B. When the handle 330 is located at any predetermined angular position, the steel ball will sink into a corresponding one of the ball sockets 368.

[0161] FIG. 33 shows an adjustable dumbbell system 400 in accordance with a fourth embodiment of the present invention. Except as otherwise described below, the adjustable dumbbell system 400 may be similar to the adjustable dumbbell system 100, 200, or 300, described above. For example, the adjustable dumbbell system 400 may include any combination of features disclosed above with reference to adjustable dumbbell system 100, adjustable dumbbell system 200, or adjustable dumbbell system 300. Without intent to limit, the adjustable dumbbell system 400 may include a handle 430, two guide tubes 460, and a first extension member 465A and a second extension member 465B accommodated in the two guide tubes 460.

[0162] The adjustable dumbbell system 400 may be adjusted in a manner similar to those described above. For example, rotating the handle 430 may drive a ring gear 471 (e.g., at each end) to rotate (e.g., about the longitudinal axis of the handle 430). The ring gear 471 may be formed or coupled with the handle 430. For example, the ring gear 471 and handle 430 may be formed integrally as a single part. In other examples, the ring gear 471 may be coupled to the handle 430. In one example, the ring gear 471 may be coupled to or formed with a tube that is connected to the handle 430. Although described with reference to rotating handle 430, the adjustable dumbbell system 400 may be actuated in a different manner, such as rotating a dial on the dumbbell or the base. For sake of convenience, only one end of the adjustable dumbbell system 400 will be described with reference to FIG. 33, with the other end operated in a similar manner.

[0163] The adjustable dumbbell system 400 may include a pinion gear 472 engaged with the ring gear 471. The pinion gear 472 may mesh with the ring gear 471, such that rotation of the ring gear 471 rotates the pinion gear 472. The pinion gear 472 may be coupled to a worm gear 473, so that rotation of the pinion gear 472 rotates the worm gear 473. The pinion gear 472 and worm gear 473 may be coaxially aligned. In one example, the pinion gear 472 is fixed to the worm gear 473 to rotate the worm gear 473 directly with the pinion gear 472. In another example, a transmission may couple the pinion gear 472 to the worm gear 473 to drive the worm gear 473 at a different ratio compared to the pinion gear 472. The pinion gear 472 and worm gear 473 may rotate about an axis parallel to the longitudinal axis of the handle 430, or the pinion gear 472 and worm gear 473 may be aligned along a different axis.

[0164] The worm gear 473 meshes with the first extension member 465A. For example, the first extension member 465A may define or include a first rack 466A. Thus, forward rotation of the handle 430 will drive the first extension member 465A to extend outward, and reverse rotation of the handle 430 will drive the first extension member 465A to retract inward. A similar configuration may be provided at the opposite end of the adjustable dumbbell assembly 400 to drive the second extension member 465B with rotation of the handle 430. In this manner, the first and second extension members 465A, 465B may be driven outward or inward with rotation of the handle 430 to selectively engage a subset of weights or weight plates, such as in a manner as described above. For example, rotating the handle 430 may drive the first and second extension members 465A, 465B to move simultaneously in the outward or inward direction to engage one or more weight plates in sequence.

[0165] FIG. 34 shows an adjustable dumbbell system 500 in accordance with a fifth embodiment of the present invention. Except as otherwise described below, the adjustable dumbbell system 500 may be similar to the adjustable dumbbell system 100, 200, 300, or 400, described above. For example, the adjustable dumbbell system 500 may include any combination of features disclosed above with reference to adjustable dumbbell system 100, adjustable dumbbell system 200, adjustable dumbbell system 300, or adjustable dumbbell system 400. Without intent to limit, the adjustable dumbbell system 500 may include a handle 530, two guide tubes 560, and a first extension member 565A and a second extension member 565B accommodated in the two guide tubes 460.

[0166] Similar to the adjustable dumbbell system 400, the adjustable dumbbell system 500 may include a ring gear 571 (e.g., at each end of the handle 530). Rotating the handle 530 or another portion of the adjustable dumbbell system 500 (e.g., a dial on the dumbbell or the base) may drive a ring gear 571 to rotate (e.g., about the longitudinal axis of the handle 530). The ring gear 571 and handle 530 may be formed integrally as a single part, or the ring gear 571 may be coupled to the handle 530. Similar to adjustable dumbbell system 400, only one end of the adjustable dumbbell system 500 is described with reference to FIG. 34, for sake of convenience. It should be understood that the other end may include a similar configuration operated in a similar manner.

[0167] The ring gear 571 may define a worm gear 573. The worm gear 573 may mesh with the first extension member 565A. For example, the first extension member 565A may define or include a first rack 566A that meshes with the worm gear 573. In this manner, the handle 530 or ring gear 571 / worm gear 573 may rotate to directly actuate the first extension member 565A. Thus, forward rotation of the handle 530 will drive the first extension member 565A to extend outward, and reverse rotation of the handle 530 will drive the first extension member 565A to retract inward. A similar configuration may be provided at the opposite end of the adjustable dumbbell assembly 500 to drive the second extension member 565B with rotation of the handle 530. As a result, the first and second extension members 565A, 565B may be driven outward or inward with rotation of the handle 530 to selectively engage a subset of weights or weight plates, such as in a manner as described above. For example, rotating the handle 530 may drive the first and second extension members 565A, 565B to move simultaneously in the outward or inward direction to engage one or more weight plates in sequence.

[0168] The description of certain embodiments included herein is merely exemplary in nature and is in no way intended to limit the scope of the disclosure or its applications or uses. In the included detailed description of embodiments of the present systems and methods, reference is made to the accompanying drawings which form a part hereof, and which are shown by way of illustration specific to embodiments in which the described systems and methods may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice presently disclosed systems and methods, and it is to be understood that other embodiments may be utilized, and that structural and logical changes may be made without departing from the spirit and scope of the disclosure. Moreover, for the purpose of clarity, detailed descriptions of certain features will not be discussed when they would be apparent to those with skill in the art so as not to obscure the description of embodiments of the disclosure. The included detailed description is therefore not to be taken in a limiting sense, and the scope of the disclosure is defined only by the appended claims.

[0169] From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention.

[0170] The particulars shown herein are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present disclosure and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of various embodiments of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for the fundamental understanding of the invention, the description taken with the drawings and / or examples making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

[0171] As used herein and unless otherwise indicated, the terms “a” and “an” are taken to mean “one”, “at least one” or “one or more”. Unless otherwise required by context, singular terms used herein shall include pluralities and plural terms shall include the singular.

[0172] Unless the context clearly requires otherwise, throughout the description and the claims, the words ‘comprise’, ‘comprising’, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. Words using the singular or plural number also include the plural and singular number, respectively. Additionally, the words “herein,”“above,” and “below” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of the application.

[0173] All relative, directional, and ordinal references (including top, bottom, side, front, rear, first, second, third, and so forth) are given by way of example to aid the reader's understanding of the examples described herein. They should not be read to be requirements or limitations, particularly as to the position, orientation, or use unless specifically set forth in the claims. Connection references (e.g., attached, coupled, connected, joined, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other, unless specifically set forth in the claims.

[0174] Of course, it is to be appreciated that any one of the examples, embodiments or processes described herein may be combined with one or more other examples, embodiments and / or processes or be separated and / or performed amongst separate devices or device portions in accordance with the present systems, devices and methods.

[0175] Finally, the above discussion is intended to be merely illustrative of the present system and should not be construed as limiting the appended claims to any particular embodiment or group of embodiments. Thus, while the present system has been described in particular detail with reference to exemplary embodiments, it should also be appreciated that numerous modifications and alternative embodiments may be devised by those having ordinary skill in the art without departing from the broader and intended spirit and scope of the present system as set forth in the claims that follow. Accordingly, the specification and drawings are to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.

Examples

second embodiment

[0115]FIGS. 11, 12 and 13 are respectively a perspective view, a side view and a top view of an adjustable dumbbell system 200 (hereinafter, sometimes simply referred to as an adjustable dumbbell) in a standby state according to the present invention. With additional reference to FIG. 14 and FIG. 15, the adjustable dumbbell system 200 includes a base 210, a plurality of first weight plates 220A, a plurality of second weight plates 220B, a first auxiliary weight plate 225A, a second auxiliary weight plate 225B and a handle assembly 202, or a combination thereof, that can be separated or combined with each other. In terms of weight selection function, the user can selectively attach the first and second weight plates 220A, 220B (hereinafter, sometimes simply called weight plates) and / or the first and second auxiliary weight plates 225A, 225B (hereinafter, sometimes simply called auxiliary weight plates) to the handle assembly 202 according to the user's personal needs, so that the use...

third embodiment

[0155]FIG. 30 shows an adjustable dumbbell system 300 in accordance with the present invention. Similar to the previous embodiment, the adjustable dumbbell system 300 includes a base 310, a plurality of first weight plates 320A, a plurality of second weight plates 320B, a first auxiliary weight plate and a second auxiliary weight plate (hidden in the figure), and a handle assembly 302. FIG. 30 depicts that the handle assembly 302 mounting all weight plates 320A, 320B and auxiliary weight plates, forming the heaviest dumbbell 304.

[0156]The handle assembly 302 also includes a handle 330, a first end seat 340A and a second end seat 340B respectively connected to the two opposite ends of the handle 330, and two guide tubes 360 connected to the two end seats 340A, 340B along the longitudinal direction, and a first extension member 365A and a second extension member 365B respectively (at least partially) accommodated in the two guide tubes 360. Referring to FIG. 31, the operation principl...

fourth embodiment

[0161]FIG. 33 shows an adjustable dumbbell system 400 in accordance with the present invention. Except as otherwise described below, the adjustable dumbbell system 400 may be similar to the adjustable dumbbell system 100, 200, or 300, described above. For example, the adjustable dumbbell system 400 may include any combination of features disclosed above with reference to adjustable dumbbell system 100, adjustable dumbbell system 200, or adjustable dumbbell system 300. Without intent to limit, the adjustable dumbbell system 400 may include a handle 430, two guide tubes 460, and a first extension member 465A and a second extension member 465B accommodated in the two guide tubes 460.

[0162]The adjustable dumbbell system 400 may be adjusted in a manner similar to those described above. For example, rotating the handle 430 may drive a ring gear 471 (e.g., at each end) to rotate (e.g., about the longitudinal axis of the handle 430). The ring gear 471 may be formed or coupled with the handl...

Claims

1. An adjustable dumbbell system comprising:a rotatable handle having a grip portion;at least one gear mechanism rotationally coupled to the rotatable handle; andat least one extension member operatively connected to the at least one gear mechanism;wherein, upon rotation of the handle, the at least one extension member extends or retracts along an extension axis to selectively engage at least one weight plate and the handle.

2. The adjustable dumbbell system of claim 1, wherein the rotatable handle includes a shaft, the shaft connected to the at least one gear mechanism, the at least one gear mechanism including a plurality of gears configured to cause movement of the at least one extension member upon rotation of the shaft.

3. The adjustable dumbbell system of claim 2, wherein the gear mechanism comprises:a ring gear coupled to an end of the shaft; andat least one of a worm gear or a spur gear configured to mesh with a rack on the at least one extension member.

4. The adjustable dumbbell system of claim 3, wherein:the at least one gear mechanism comprises a first gear mechanism disposed at a first end of the shaft and a second gear mechanism disposed at a second, opposite end of the shaft;the at least one extension member comprises a first extension member operatively connected to one of the first gear mechanism or the second gear mechanism, and a second extension member operatively connected to the other of the first gear mechanism or the second gear mechanism;wherein, upon rotation of the handle, the first extension member and the second extension member synchronously extend or retract along respective extension axes to selectively engage at least one respective weight plate and the handle.

5. The adjustable dumbbell system of claim 4, wherein the first extension member is disposed at a 3 o'clock, 4 o'clock, 5 o'clock, or 6 o'clock position, and the second extension member is disposed at a 6 o'clock, 7 o'clock, 8 o'clock, or 9 o'clock position with respect to an inner wall of the adjustable dumbbell.

6. The adjustable dumbbell system of claim 1, wherein the at least one weight plate includes a recess adapted to receive the at least one extension member.

7. The adjustable dumbbell system of claim 6, further comprising a base comprising a plurality of positioning walls and positioning recesses configured to align the recess of the at least one weight plate to form a channel that receives the at least one extension member.

8. The adjustable dumbbell system of claim 1, wherein the at least one extension member is disposed at a 3 o'clock, 4 o'clock, 5 o'clock, 6 o'clock, 7 o'clock, 8 o'clock, or 9 o'clock position with respect to an inner wall of the adjustable dumbbell.

9. The adjustable dumbbell system of claim 1, further comprising at least one inner wall disposed at an end of the handle, wherein the handle and the at least one gear mechanism rotate relative to the at least one inner wall.

10. The adjustable dumbbell system of claim 1, further comprising a locking mechanism that prevents actuation of the at least one gear mechanism when the handle is disengaged from a base.

11. The adjustable dumbbell system of claim 1, further comprising a base comprising a lock feature configured to engage with locking members to prevent removal of the handle from the base when weight plates are improperly selected.

12. The adjustable dumbbell system of claim 1, wherein the at least one extension member comprise a plurality of detents configured to assist a user in selecting predetermined weight increments.

13. The adjustable dumbbell system of claim 1, wherein the at least one weight plate includes multiple weight plates including opposing grooves and ridges that interlock to prevent dislodgement of the weight plates from the handle when the handle is removed from a base.

14. The adjustable dumbbell system of claim 1, wherein the at least one extension member includes a stop to prevent overextension beyond a designated length.

15. An adjustable dumbbell system comprising:a base;a plurality of weight plates configured to rest on the base;an adjustable dumbbell removably secured to the base, the dumbbell comprising:a rotatable handle,at least two extension members,at least two gear mechanisms, each of the at least two gear mechanisms operatively coupled to a respective one of the at least two extension members;wherein the rotatable handle is operatively connected to the at least two gear mechanisms which extends the at least two extension members along respective extension axes thereof to engage a selection of one or more weight plates from the base.

16. The adjustable dumbbell system of claim 15, wherein the rotatable handle includes a shaft, the shaft connected to the at least two gear mechanisms, the at least two gear mechanisms configured to cause synchronous movement of the at least two extension members upon rotation of the shaft.

17. The adjustable dumbbell system of claim 16, wherein the at least two gear mechanisms each comprise:a ring gear coupled to an end of the shaft; anda spur gear or a worm gear configured to mesh with a rack on each respective extension member.

18. The adjustable dumbbell system of claim 15, wherein each weight plate includes a recess adapted to receive an extension member of the at least two extension members.

19. The adjustable dumbbell system of claim 18, wherein the base includes a plurality of positioning walls configured to align the recess of each weight plate to form a channel that receives the extension member.

20. The adjustable dumbbell system of claim 15, further comprising a locking mechanism that prevents actuation of the at least two gear mechanisms when the dumbbell is disengaged from the base.

21. The adjustable dumbbell system of claim 15, wherein the base includes a lock feature configured to engage with locking members on the dumbbell to prevent removal of the handle from the base when weight plates are improperly selected.

22. The adjustable dumbbell system of claim 15, wherein at least one of the at least two extension members comprises a plurality of detents configured to assist a user in selecting predetermined weight increments.

23. The adjustable dumbbell system of claim 15, wherein the plurality of weight plates include opposing grooves and ridges that interlock to prevent dislodgement of the plurality of weight plates from the handle when the handle is removed from the base.

24. The adjustable dumbbell system of claim 15, wherein at least one of the at least two extension members includes a stop to prevent overextension beyond a designated length.

25. (canceled)26. (canceled)27. (canceled)28. An adjustable dumbbell system comprising:a base having two opposite ends, and a longitudinal direction defined by the two ends;a plurality of first weight plates configured to rest on one end of the base along the longitudinal direction;a plurality of second weight plates configured to rest on the other end of the base along the longitudinal direction; anda handle assembly arranged between the two ends of the base, the handle assembly comprising:a handle configured for allowing a user to grasp, having a first end corresponding to the first weight plates and a second end corresponding to the second weight plates;a first end seat and a second end seat respectively connected to the first end and the second end of the handle;at least one enclosure connecting the first end seat and the second end seat along the longitudinal direction, wherein the at least one enclosure is located outside the handle and separated by a distance that does not hinder the user from gripping the handle; anda first extension member and a second extension member, each being operable to extend or retract into the enclosure along the longitudinal direction, the first extension member and second extension member being interconnected to each other, so that the first extension member and the second extension member can be operated to move in opposite directions in the longitudinal direction;wherein the first extension member is operable to extend from the enclosure and the first end seat in a direction away from the second end seat to engage the first weight plates in sequence, and the second extension member is operable to extend from the enclosure and the second end seat in a direction away from the first end seat to engage the second weight plates in sequence, so that the handle assembly is operable to selectively engage the first weight plates and the second weight plates.

29. The adjustable dumbbell system of claim 28, wherein:the first end seat comprises a first transmission mechanism operatively connected to the first extension member to convert a rotational movement into a linear movement of the first extension member in the longitudinal direction;the second end seat comprises a second transmission mechanism operatively connected to the second extension member to convert a rotational movement into a linear movement of the second extension member in the longitudinal direction; andthe rotational movement of the first transmission mechanism is interconnected with the rotational movement of the second transmission mechanism.

30. The adjustable dumbbell system of claim 29, wherein:the first extension member is provided with a first rack extending in the longitudinal direction, the first transmission mechanism having at least one first gear, one of the at least one first gear configured to mesh with the first rack on the first extension member; andthe second extension member is provided with a second rack extending in the longitudinal direction, the second transmission mechanism having at least one second gear, one of the at least one second gear configured to mesh with the second rack on the second extension member.

31. The adjustable dumbbell system of claim 30, wherein one of the at least one first gear of the first transmission mechanism is coaxially connected to one of the at least one second gear of the second transmission mechanism, with a rotation axis corresponding to the longitudinal direction and passing through an interior of the handle.

32. The adjustable dumbbell system of claim 31, wherein:the handle assembly is provided with a weight selection portion that can be rotated by the user, and rotation of the weight selection portion drives the first gear and the second gear to rotate synchronously;when the weight selection portion is operated to rotate in a forward rotation direction by a predetermined angle, the first extension member can be moved in the direction away from the second end seat by a predetermined distance, while the second extension member can be moved in the direction away from the first end seat by the predetermined distance simultaneously; andwhen the selection portion is operated to rotate in a reverse rotation direction by the predetermined angle, the first extension member can be moved in a direction close to the second end seat by the predetermined distance, while the second extension member can be moved in a direction close to the first end seat by the predetermined distance.

33. The adjustable dumbbell system of claim 32, wherein the handle at least partially forms the weight selection portion, which can rotate about the rotation axis with respect to the first end seat and the second end seat.

34. The adjustable dumbbell system of claim 32, further comprisinga first auxiliary weight plate and a second auxiliary weight plate resting on predetermined positions of the base, respectively corresponding to locations of the first end seat and the second end seat of the handle assembly when resting on the base;the first end seat and the second end seat respectively provided with a first engaging member and a second engaging member that can be driven by the weight selection portion;wherein:the weight selection portion is operable to be rotated to one of a plurality of predetermined angular positions;when the weight selection portion is in some of the predetermined angular positions, the first engaging member and the second engaging member do not engage the first auxiliary weight plate and the second auxiliary weight plate; andwhen the weight selection portion is in the others of the predetermined angular positions, the first engaging member and the second engaging member respectively engage the first auxiliary weight plate and the second auxiliary weight plate, so that the handle assembly is operable to selectively engage the first auxiliary weight plate and the second auxiliary weight plate.

35. The adjustable dumbbell system of claim 34, wherein:the first auxiliary weight plate and the second auxiliary weight plate each comprises a lock portion;the first engaging member and the second engaging member each comprises at least one convex lump, which can be driven by the weight selection portion to rotate around the rotation axis;when the weight selection portion is in some of the predetermined angular positions, all the convex lumps of the first and second engaging members are not blocked under the respective lock portions of the first auxiliary weight plate and the second auxiliary weight plate; andwhen the weight selection portion is in the others of the predetermined angular positions, one convex lump of the first engaging member is blocked under the lock portion of the first auxiliary weight plate, and one convex lump of the second engaging member is blocked under the lock portion of the second auxiliary weight plate.

36. The adjustable dumbbell system of claim 34, whereinany two adjacent predetermined angular positions of the weight selection portion are separated by one unit angle;when the weight selection portion rotates one unit angle from one of the predetermined angular positions to another one, the handle assembly is operable to be changed from one state of engaging the first and second auxiliary weight plates to another state of disengaging the first and second auxiliary weight plates, or changed from the state of disengaging the first and second auxiliary weight plates to the state of engaging the first and second auxiliary weight plates;when the weight selection portion rotates one unit angle twice in the forward rotation direction from one of the predetermined angular positions to another one, the handle assembly is operable to additionally engage one of the first weight plates and one of the second weight plates; andwhen the weight selection portion rotates one unit angle twice in the reverse rotation direction from one of the predetermined angular positions to another one, the handle assembly is operable to disengage one of the first weight plates and one of the second weight plates.

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