Variable-length shaft and adjustable mass for a golf club

Abstract

To improve adjustability of a shaft length without substantially affecting total weight, swing weight or appearance of a golf club.SOLUTION: There is provided a golf club, including: a first shaft 22 coupled to a club head; a second shaft 120 configured to slidably engage a portion of the first shaft; a grip 34 coupled to the second shaft; and an adjustable length shaft assembly 800; wherein the adjustable length shaft assembly is received by the second shaft and configured to allow a portion of the first shaft to slide in relation to the second shaft in a first configuration, and to restrict a portion of the first shaft from sliding in relation to the second shaft in a second configuration. The grip is restricted from rotation about the first shaft or the second shaft as the first shaft slides in relation to the second shaft.SELECTED DRAWING: Figure 35

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application is a continuation - in - part of U.S. non - provisional patent application Ser. No. 15 / 165,889, filed May 26, 2016, which claims the benefit of U.S. provisional patent application Ser. No. 62 / 167,833, filed May 28, 2015; U.S. provisional patent application Ser. No. 62 / 220,013, filed Sep. 17, 2015; U.S. provisional patent application Ser. No. 62 / 258,837, filed Nov. 23, 2015; and U.S. provisional patent application Ser. No. 62 / 303,429, filed May 4, 2016. This application also claims the benefit of U.S. provisional patent application Ser. No. 62 / 718,298, filed Aug. 13, 2018. The entire contents of all of the above disclosures are hereby incorporated by reference in their entirety into this specification.

[0002] This disclosure relates to golf clubs, and more particularly to golf clubs having a variable - length shaft that allows for selective extension or shortening of the club. In addition, this disclosure relates to adjustable masses within a golf club shaft that allow for selective adjustment of the swing weight and moment of inertia of the club while maintaining the overall weight of the club.

Background Art

[0003] Golf clubs come in various forms such as woods, hybrids, irons, wedges, or putters, and these clubs generally differ in head shape and design (e.g., the difference between a wood and an iron), club - head material, shaft material, club length, and club loft.

[0004] Generally, when assembling a known golf club, the shaft is cut or trimmed to the desired length. Woods and hybrids generally have longer shafts than irons, wedges, and putters, and putters generally have the shortest shaft lengths. After the shaft is trimmed to the desired length, the shaft is attached to the golf club head by a hosel. The shaft is typically attached to the golf club head by epoxy or other adhesive. However, in some golf clubs, the shaft is connected to an adapter, and the adapter engages a removable threaded member within the hosel to secure the shaft to the golf club head. A grip is then installed on the shaft.

[0005] After assembling these known golf clubs, it is difficult to adjust the shaft length. The first option is to remove the original shaft and replace it with a new shaft of a different length. Unfortunately, this option results in an additional cost for the new shaft. The second option is to remove the grip, cut a portion of the butted end of the shaft (e.g., the end of the shaft opposite the golf club head) to shorten the shaft or install a shaft extension within the butted end of the shaft to lengthen the shaft, and then install a new grip. This option not only results in an additional cost associated with the new grip, but adjusting the shaft length at the butted end changes the swing weight of the golf club (specifically, shortening decreases the swing weight while lengthening increases the swing weight), changes the total weight of the golf club (shortening decreases the total weight while lengthening increases the total weight), and changes the shaft stiffness (shortening generally increases the shaft stiffness while lengthening generally decreases the shaft stiffness). Neither option is desirable for the average golfer due to the additional cost, the time required to repair or adjust the golf club, and / or the detrimental changes to the total weight of the golf club, the swing weight of the golf club, and / or the stiffness of the shaft.

[0006] These are known options for adjusting a golf club shaft, but there is a need to improve the adjustability of the shaft length without substantially affecting the total weight, swing weight, or appearance of the golf club.

Brief Description of the Drawings

[0007]

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[0008] The embodiments of the present invention discussed below are directed to a golf club having a first shaft connected to a club head, a second shaft configured to slidably engage a portion of the first shaft, a grip connected to the second shaft, and a variable length shaft assembly configured to be received by the second shaft and allow a portion of the first shaft to slide relative to the second shaft. The variable length shaft assembly further includes an insert that is connected to an axial end face of the first shaft having an engagement with a screw with a threaded portion. The screw with a threaded portion is configured to rotate, and the insert and the first shaft are configured to translate together along the screw with a threaded portion to adjust the length of the golf club. The insert further includes a bump projection positioned on an outer surface of the insert and a rib positioned on an inner surface of the insert to minimize lateral or radial movement between the first shaft and the second shaft during operation of the variable length shaft assembly.

[0009] In one embodiment, a golf club has a first shaft connected to a club head, a second shaft configured to slidably engage a portion of the first shaft, a grip connected to the second shaft, and a variable length shaft assembly. The variable length shaft assembly is received within the second shaft and is configured to allow a portion of the first shaft to slide relative to the second shaft in a first configuration and to limit sliding of a portion of the first shaft relative to the second shaft in a second configuration. The grip is restricted from rotating about the first shaft or the second shaft when the first shaft slides relative to the second shaft.

[0010] In another embodiment, a golf club includes a shaft connected to a club head, a grip connected to the first shaft, and an adjustable mass assembly received by the shaft. The adjustable mass assembly has a mass configured to move within the shaft between the club head and the grip.

[0011] A method of manufacturing a golf club with an adjustable length includes connecting a first shaft to a club head, connecting a retainer to the first shaft, connecting a variable length shaft assembly to a second shaft, and connecting the first shaft to the second shaft, where the retainer engages the variable length shaft assembly.

[0012] Other features and aspects will become apparent by considering the following detailed description and the accompanying drawings. Before any particular embodiment of the disclosure is described in detail, it is to be understood that the disclosure is not limited in its application to the details of components or to the construction and arrangement shown in the following description or illustrated in the drawings. The disclosure is capable of supporting other embodiments and of being practiced or carried out in various ways. It is to be understood that the description of specific embodiments is not intended to limit the disclosure, which covers all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure. Also, the terminology and phraseology used herein is for the purpose of description and should not be regarded as limiting.

[0013] Terms such as "first," "second," "third," and "fourth" in the detailed description and claims are used, if at all, to distinguish between similar elements and are not necessarily used to describe a particular sequential or chronological order. Such terms are interchangeable under appropriate circumstances, and it is to be understood that the embodiments described herein are capable of operating in sequences other than those illustrated or otherwise described herein. Moreover, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that comprises a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus.

[0014] Terms such as "left", "right", "front", "back", "top", "bottom", "upper", and "lower" in the detailed description and claims are used for illustrative purposes, if any, and are not necessarily used to describe permanent relative positions. Such terms are interchangeable under appropriate circumstances, and it should be understood that the embodiments of the devices, methods, and / or articles of manufacture described herein are capable of operating in orientations other than those illustrated or otherwise described herein, for example.

[0015] Terms such as "connecting", "connected", "connection", and "connecting" should be understood broadly and represent connecting two or more elements mechanically or in another way. The connection (either mechanically or in another way) can be for any length of time, for example, permanently or semi-permanently, or only instantaneously.

[0016] For ease of discussion and understanding, and for illustrative purposes only, the following detailed description illustrates the putter as golf club 10. It should be recognized that the putter is provided for illustrative purposes of a variable length shaft assembly that increases or decreases the shaft length of a golf club, and also for illustrative purposes of an adjustable mass assembly that adjusts swing weight and moment of inertia while maintaining the total weight of the golf club. The disclosed variable length shaft assembly and / or adjustable mass assembly can be used in connection with any desired driver, fairway wood, wood in general, hybrid, iron, wedge, putter, or other golf club.

[0017] Referring now to the drawings, FIGS. 1-2 illustrate an embodiment of a golf club 10 incorporating a variable length shaft assembly. The golf club 10 includes a club head 14 having a hosel 18. A first shaft 22 is attached to the hosel 18 at a first end or tip 26, while a second end or butt 30 of the shaft 22 (shown in FIG. 6) is received by a grip 34. The shaft 22 extends along an axis A. In FIG. 1, the shaft 22 is shown in a first shaft length configuration having a first club length L1, and the shaft 22 has a first balance point 38. In FIG. 2, the shaft 22 is shown in a second shaft length configuration having a second club length L2, and the shaft 22 has a second balance point 42. The second club length L2 is less than the first club length L1. Due to the shorter club length L2, the second balance point 42 of the shaft 22 is closer to the club head 14 than the first balance point 38 of the shaft 22 associated with the longer club length L1. The variable length shaft assembly is contained within the shaft 22 and the grip 34 and generally cannot be seen from outside the golf club 10.

[0018] In various embodiments, the club length of the golf club 10 can be any suitable or desired club length. For example, the club length can be 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 inches or more. A variable length shaft assembly as disclosed herein can adjust the club length between any suitable or desired range of club lengths. For example, the variable length shaft assembly can adjust the club length by approximately 0 to 15 inches, 0 to 14 inches, 0 to 13 inches, 0 to 12 inches, 0 to 11 inches, 0 to 10 inches, 0 to 9 inches, 0 to 8 inches, 0 to 7 inches, 0 to 6 inches, 0 to 5 inches, 0 to 4 inches, 0 to 3 inches, 0 to 2 inches, 0 to 1 inch, or any other suitable range of adjustment of the club length.

[0019] As a non-limiting example with respect to a putter, the variable length shaft assembly can adjust the club length from a first club length L1 of approximately 36 inches to a second club length L2 of approximately 30 inches. It should be recognized that the first club length L1 and the second club length L2 can be any suitable or desired respective club lengths, including the exemplary club lengths disclosed herein.

[0020] In this example, the club length is adjustable between 0 to 6 inches. In other examples, the variable length shaft assembly can adjust the club length by approximately 0 to 15 inches, 0 to 14 inches, 0 to 13 inches, 0 to 12 inches, 0 to 11 inches, 0 to 10 inches, 0 to 9 inches, 0 to 8 inches, 0 to 7 inches, 0 to 5 inches, 0 to 4 inches, 0 to 3 inches, 0 to 2 inches, 0 to 1 inch, or any other suitable range of adjustment of the club length.

[0021] As a non-limiting example regarding a driver, a variable-length shaft assembly is capable of adjusting the club length from a first club length L1 of approximately 48 inches to a second club length L2 of approximately 44 inches. It should be recognized that the first club length L1 and the second club length L2 can be any appropriate or desired respective club lengths, including any of the exemplary club lengths disclosed herein. In this example, the club length is adjustable between 0 and 4 inches. In other examples, the variable-length shaft assembly can adjust the club length by approximately 0 to 15 inches, 0 to 14 inches, 0 to 13 inches, 0 to 12 inches, 0 to 11 inches, 0 to 10 inches, 0 to 9 inches, 0 to 8 inches, 0 to 7 inches, 0 to 6 inches, 0 to 5 inches, 0 to 3 inches, 0 to 2 inches, 0 to 1 inch, or any other appropriate range of adjustment of the club length.

[0022] As a non-limiting example regarding a fairway wood, a variable-length shaft assembly is capable of adjusting the club length from a first club length L1 of approximately 44 inches to a second club length L2 of approximately 38 inches. It should be recognized that the first club length L1 and the second club length L2 can be any appropriate or desired respective club lengths, including any of the exemplary club lengths disclosed herein. In this example, the club length is adjustable between 0 and 6 inches. In other examples, the variable-length shaft assembly can adjust the club length by approximately 0 to 15 inches, 0 to 14 inches, 0 to 13 inches, 0 to 12 inches, 0 to 11 inches, 0 to 10 inches, 0 to 9 inches, 0 to 8 inches, 0 to 7 inches, 0 to 5 inches, 0 to 4 inches, 0 to 3 inches, 0 to 2 inches, 0 to 1 inch, or any other appropriate range of adjustment of the club length.

[0023] As a non-limiting example related to hybrids, a variable-length shaft assembly can adjust the club length from a first club length L1 of approximately 42 inches to a second club length L2 of approximately 35 inches. It should be recognized that the first club length L1 and the second club length L2 can be any appropriate or desired respective club lengths, including any of the exemplary club lengths disclosed herein. In this example, the club length is adjustable between 0 and 7 inches. In other examples, the variable-length shaft assembly can adjust the club length by any other appropriate range of adjustment of the club length, such as approximately 0 to 15 inches, 0 to 14 inches, 0 to 13 inches, 0 to 12 inches, 0 to 11 inches, 0 to 10 inches, 0 to 9 inches, 0 to 8 inches, 0 to 6 inches, 0 to 5 inches, 0 to 4 inches, 0 to 3 inches, 0 to 2 inches, 0 to 1 inch.

[0024] As a non-limiting example related to one or more irons or wedges, a variable-length shaft assembly can adjust the club length from a first club length L1 of approximately 42 inches to a second club length L2 of approximately 35 inches. It should be recognized that the first club length L1 and the second club length L2 can be any appropriate or desired respective club lengths, including any of the exemplary club lengths disclosed herein.

[0025] It should be recognized that the adjustment of the club length by the variable-length shaft assembly as described herein is not discrete. Rather, the variable-length shaft assembly described herein allows adjustment of the club length to any length or position between the first club length L1 and the second club length L2.

[0026] Figures 3-7 illustrate a first embodiment of a variable length shaft assembly 100. The first embodiment of the assembly 100 generally uses a screw 140 with a threaded portion, which is disclosed in the following additional details and selectively adjusts and maintains the length of the golf club 10. Referring to FIG. 3, the grip 34 defines an aperture 46 at the end face 50. The aperture 46 provides access to a rotating screw head 104 having a polygonal socket 108 as shown in FIGS. 4-5. The aperture 46 in the grip 34 can be a vent hole in the grip 34. However, in other embodiments, the aperture 46 is a specially designed hole or a custom hole through the grip and can provide sufficient access to the socket 108. As a non-limiting example, the aperture 46 can be a hole larger than a typical vent hole, sized sufficient to receive a torque wrench, and facilitating the engagement of the torque wrench with the socket 108. The socket 108 is illustrated as a star-shaped socket, but in other embodiments, the socket 108 can be of any suitable shape, such as triangular, square, slot, Phillips®, Torx®, POSIDRIV®, SUPADRIVE®, pentagonal, hexagonal, or any other suitable polygon or other shape fixed to a corresponding torque wrench or adjustment tool.

[0027] Referring to FIGS. 4-5, the screw head 104 is received by a retainer 112, which is stationary with respect to the second shaft 120 but allows rotation of the screw head 104. The retainer 112 is itself received by a second end or abutting end 116 of the second shaft 120. The second shaft 120 includes a slot or cutout 124 that extends along an axis A (shown in FIG. 4) in a direction from the second end 116 toward the club head 14. In the illustrated embodiment, the slot 124 is approximately 5 inches in length. However, in other embodiments, the slot 124 can have a length ranging from approximately 1 inch to approximately 9 inches, more specifically, a length ranging from approximately 2 inches to approximately 8 inches, more specifically, a length ranging from approximately 3 inches to approximately 7 inches, more specifically, a length ranging from approximately 4 inches to approximately 6 inches, or any suitable or desired length that can correspond to the adjustable length of the golf club 10. In addition, although the slot 124 is shown as an open slot (i.e., extending through the second shaft 120), in other embodiments, the slot 124 can be a closed slot, such as, but not limited to, a channel or guide channel. Further, although the slot 124 is shown as extending through the second shaft 120 at the second end 116, in other embodiments, the slot 124 need not extend through the second end 116 and can be positioned anywhere along the second shaft 120 or provided in other ways.

[0028] Figures 5-6 show the insert 128, which is received within the second end 30 of the first shaft 22. The insert 128 has a protrusion 132 that extends beyond the outer peripheral portion of the first shaft 22. The protrusion 132 is fixed so as to be received by the slot 124. Further, the insert 128 defines an aperture 136 with a threaded portion.

[0029] Referring to FIG. 7, the aperture 136 with a threaded portion receives a corresponding screw 140 with a threaded portion that extends away from the screw head 104. In addition, the grip 34 is attached to the second shaft 120 and not to the first shaft 22. The first shaft 22 is received by the second shaft 120, allowing the first and second shafts 22, 120 to move axially relative to each other.

[0030] As shown in FIG. 7, the second shaft 120 is made of graphite, while the insert 128 is made of aluminum. These materials are lightweight and minimize the impact of the variable-length shaft assembly 100 on the swing weight and total weight of the golf club 10. In other embodiments, the retainer 112, the second shaft 120, and the insert 128 can be made of any suitable or desired materials including, but not limited to, aluminum, steel, titanium, graphite, other metals, composites, metal alloys, polymers, polyurethanes, thermoplastic polyurethanes, thermoplastic elastomers, reinforced polyurethanes, polyethylene, polypropylene, polytetrafluoroethylene, polyisobutylene, polyvinyl chloride, polyamides, nylon 66, or any other material. Further, the retainer 112, the second shaft 120, and the insert 128 can be made of the same material or the retainer 112, the second shaft 120, and the insert 128 can be made of different materials. In one example, the second shaft 120 and the insert 128 can be made of nylon 66.

[0031] In other embodiments, the retainer 112, the second shaft 120, or the insert 128 can be made from the materials described above and can further include a filler. The filler can be glass, carbon fiber, metal, or any other suitable filler. The material of the retainer 112, the second shaft 120, or the insert 128 can include the volume percentage of the filler. In some embodiments, the material of the retainer 112, the second shaft 120, or the insert 128 can include from 0 to 90% filler volume. In some embodiments, the material of the retainer 112, the second shaft 120, or the insert 128 can include from 0 to 50%, or from 50 to 90% filler volume. In some embodiments, the material of the retainer 112, the second shaft 120, or the insert 128 can include from 0 to 40%, 10 to 50%, 20 to 60%, 30 to 70%, 40 to 80%, 50 to 90%, or 60 to 100% filler volume. For example, the material of the retainer 112, the second shaft 120, or the insert 128 can include 0%, 10%, 20%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 90% filler volume. In a further example, the insert 128 can be made from nylon 66 having 30% carbon fiber filler volume. In a further example, the insert 128 can be made from nylon 66 having 50% glass filler volume. In a further example, the retainer 112 can be made from nylon 66 having 50% glass filler volume. In a further example, the second shaft 120 can be made from nylon 66 having 30% carbon fiber filler volume.

[0032] In the operation of the variable length shaft assembly 100, the user inserts a portion of a torque wrench into the aperture 46 defined by the grip 34 and engages the torque wrench with the socket 108 of the screw head 104. To increase the club length of the golf club 10, the user rotates the torque wrench in a first direction to rotate the screw head 104 and the associated screw 140 within the retainer 112. The threaded portion of the screw 140 meshes with the threaded portion of the aperture 136 in the insert 128. The protrusion 132 fixes the rotational position of the insert 128 relative to the second shaft 120, such that rotation of the screw 140 drives the insert 128 axially along the slot 124. As the screw 140 rotates in the first direction, the protrusion 132 translates within the slot 124 and moves the insert 128 away from the second end 116 and the first shaft 22 away from the second shaft 120. The insert 128 and the first shaft 22 move together and away from the second end 116 as the screw 140 rotates in the first direction. The insert 128 is positioned away from the second end 116 in an extended or expanded configuration. The protrusion 132 within the slot 124 also limits rotation of the second shaft 120 relative to the first shaft 22 and maintains the orientation of the grip 34 relative to the club head 14 (or put another way, the protrusion 132 limits rotation of the grip 34 around the first shaft 22). This is advantageous for a particular club, such as a putter having a paddle grip 34 (i.e., a flat surface on the grip 34), to maintain the paddle's orientation with respect to the club head 14 as the club length increases (or decreases). Once the desired club length is obtained, the user removes the torque wrench from the screw head 104 and temporarily locks the variable length shaft assembly at the desired club length.

[0033] Similarly, to decrease the club length of the golf club 10, the user engages a torque wrench with the socket 108 of the screw head 104 and rotates the torque wrench in a second direction opposite the first direction. As the screw 140 rotates in the second direction, the insert 128 moves toward the second end 116 and the first shaft 22 moves toward the second shaft 120. The insert 128 and the first shaft 22 move together toward the second end 116 as the screw 140 rotates in the second direction. The insert 128 can abut or be adjacent to the retainer 112 in the fully contracted configuration. The protrusion 132 within the slot 124 also limits rotation of the second shaft 120 relative to the first shaft 22 and maintains the orientation of the grip 34 relative to the club head 14 (or limits rotation of the grip 34 around the first shaft 22). When the desired club length is obtained, the user removes the torque wrench from the screw head 104 and temporarily locks the variable length shaft assembly at the desired club length.

[0034] The screw 140 with a threaded portion can be a single-thread screw having a single threaded portion, or the screw 140 with a threaded portion can be a multi-thread screw having two or more threaded portions. The threaded portion of the screw 140 with a threaded portion can be continuous along the length of the screw 140 with a threaded portion. In other embodiments, the threaded portion of the screw 140 with a threaded portion can be intermittent along the length of the screw 140 with a threaded portion. For example, the screw 140 with a threaded portion can have one, two, three, four, five, or any other number of threaded portions. In embodiments where the screw 140 with a threaded portion is a multi-thread screw, length adjustment can be performed by rotating a torque wrench less than that for a single-thread screw with a threaded portion. Thus, a multi-thread screw with a threaded portion can enable faster length adjustment of the golf club 10 having the variable-length shaft assembly 100. The screw 140 with a threaded portion has at least one channel passing through along the length of the screw 140 with a threaded portion, and can facilitate the molding process (not shown). The channel passing through along the length of the screw 140 with a threaded portion can divide the threaded portion into one or more regions with threaded portions. In the one or more regions with threaded portions, regions without threaded portions can be interspersed along the length of the screw 140 with a threaded portion (not shown). In other words, the one or more regions with threaded portions can be separated by regions without threaded portions along the length of the screw 140 with a threaded portion (not shown). In one embodiment, the screw 140 with a threaded portion can have at least one channel, two channels, three channels, or four channels passing through along the length of the screw with a threaded portion. In another embodiment, the screw 140 with a threaded portion has two channels cut into the threaded portions on both sides of the screw 140 with a threaded portion, and can facilitate the molding process. The channel can pass through a part or all of the length of the screw 140 with a threaded portion (not shown).

[0035] When the user increases or decreases the length of the golf club 10, the torque wrench can be a torque limiting tool 150 to prevent the user from applying excessive torque to the screw head 104. FIG. 8 illustrates an example of an embodiment of the torque limiting tool 150. The tool 150 includes a handle 154, and the handle 154 is attached to the tip 158 by a torque limiting joint 162. When the user applies a torque greater than a predetermined torque to the handle 154, the joint 162 slips or locks to prevent the transmission of excessive torque to the tip 158 and to prevent possible damage to the components of the variable length shaft assembly 100.

[0036] In the illustrated embodiment, the second shaft includes slots and the insert includes protrusions. In other embodiments, the second shaft can include two or more slots and the insert can include two or more protrusions. The second shaft can have any number of slots, such as one, two, three, four, five, or any other number of slots. The insert can have any number of protrusions corresponding to the number of slots, such as one, two, three, four, five, or any other number of protrusions. For example, the second shaft can include three slots corresponding to three protrusions on the insert, or the second shaft can include four slots corresponding to four protrusions on the insert. In some embodiments, the slots can be positioned equidistantly or asymmetrically around the second shaft. Further, the protrusions can be positioned equidistantly or asymmetrically around the insert.

[0037] In yet other embodiments, the second shaft can include one or more protrusions, and the insert can include one or more slots. In these or other embodiments, the second shaft can have any number of protrusions, such as one, two, three, four, five, or any other number of protrusions. In these or other embodiments, the insert can have any number of slots corresponding to the number of protrusions, such as one, two, three, four, five, or any other number of slots. For example, the second shaft can include three protrusions corresponding to three slots on the insert, or the second shaft can include four protrusions corresponding to four slots on the insert. In some embodiments, the protrusions can be positioned equidistantly or asymmetrically around the second shaft. Further, the slots can be positioned equidistantly or asymmetrically around the insert.

[0038] Figures 9-13 illustrate a second embodiment of the variable length shaft assembly 200. The assembly 200 has elements common to the assembly 100, and the common elements are given the same reference numbers. The second embodiment of the assembly 200 includes a compression assembly 204 that generally uses an elastic compression member, which is disclosed in further detail below, to selectively adjust and maintain the length of the golf club 10.

[0039] Referring to FIG. 9, the grip 34 defines an aperture 46 at the second end 50. The aperture 46 provides access to the compression assembly 204 (shown in FIGS. 11-12), and more specifically, provides access to an adjustment member 208 (shown in FIGS. 11-12) that carries a socket 108 (shown in FIG. 12). The grip 34 is attached to the second shaft 120 (shown in FIG. 10) but not to the first shaft 22.

[0040] As shown in FIGS. 10-11, the first shaft 22 is received by the second shaft 120, allowing the first and second shafts 22, 120 to move axially relative to each other. The insert 128 is fixed to the second end 30 of the first shaft 22 (shown in FIG. 11). The insert 128 also includes a protrusion 132 that extends beyond the outer peripheral portion of the first shaft 22. The second shaft 120 includes a slot 124 that extends axially along the second shaft 120 in a direction from the second end 116 toward the club head 14. The protrusion 132 is fixed to be received by the slot 124.

[0041] Referring now to FIGS. 11-12, the compression assembly 204 includes an adjustment member 208 and a retainer 212. The adjustment member 208 includes a head or head portion 216 that is connected to a member or shaft portion 220. The member 220 extends into the second shaft 120 away from the head 216. In the illustrated embodiment, the head 216 has a diameter that is generally larger than the diameter of the member 220. However, in other embodiments, the head 216 can have a diameter that is approximately the same size as the diameter of the member 220, or a diameter that is generally smaller than the diameter of the member 220.

[0042] Retainer 212 includes well 224, which defines a recess connected to a tubular portion 228. The tubular portion 228 extends into the second shaft 120 away from the well 224. Also, the tubular portion 228 defines an opening or open end 230 (shown in FIGS. 11 and 13) at the end of the tubular portion 228 opposite the well 224. Retainer 212 is received by the second shaft 120 through the second end 116. In addition, retainer 212, and more specifically, well 224, is attached to the second shaft 120 at the second end 116. Retainer 212 does not rotate independently of the second shaft 120 or move in any other way. Instead, retainer 212 moves with the second shaft 120. In the illustrated embodiment, well 224 has a diameter that is generally larger than the diameter of the tubular portion 228. However, in other embodiments, well 224 can have a diameter approximately the same size as the diameter of the tubular portion 228 or a diameter that is generally smaller than the diameter of the tubular portion 228.

[0043] Retainer 212 slidably receives adjustment member 208 such that adjustment member 208 can slide within retainer 212. Well 224 slidably receives head 216, while the tubular portion 228 slidably receives member 220, which extends out from the open end 230 through the tubular portion 228. To facilitate the slidable movement of adjustment member 208 within retainer 212, the tubular portion 228 has an inner diameter complementary to the outer diameter of member 220. Similarly, well 224 has an inner diameter complementary to the outer diameter of head 216. The complementary sizes allow adjustment member 208 to slide relative to retainer 212 in an axial direction or a direction generally parallel to the first and second shafts 22, 120.

[0044] The adjusting member 208 is elastically connected to the retainer 212 by a biasing member or spring 232. In the illustrated embodiment, the biasing member 232 is connected to the adjusting member 208, and more specifically, is connected to the head 216 of the adjusting member 208. Also, the biasing member 232 is received by the well 224 of the retainer 212.

[0045] Returning to FIG. 11, the insert 128 defines an aperture 236. The aperture 236 receives the retainer 212, and more specifically, receives the tubular portion of the retainer 212. The aperture 236 has an inner diameter complementary to the outer diameter of the retainer 212 and allows the insert 128 to slide along the retainer 212. In the illustrated embodiment, during adjustment of the shaft length of the golf club, the insert 128 slides along the tubular portion of the retainer 212.

[0046] As shown in FIGS. 11 and 13, the compression assembly 204 includes a deformable or elastic member or stopper 240. The elastic member 240 provides a selective expansion force between the first shaft 22 and the tubular portion and selectively holds the compression assembly 204, and the second shaft 120 to be attached, by the first shaft 22. The selective expansion force limits movement between the first shaft 22 and the second shaft 120. In the illustrated embodiment, the elastic member 240 is held between the adjusting member 208 and the retainer 212 by the compression assembly 204.

[0047] In the illustrated embodiment, the elastic member 240 generally has a cylindrical shape and includes a central channel 244 that receives the compression assembly 204 and, more specifically, receives the retainer 212 that carries the adjustment member 208. The adjustment member 208 preferably extends completely through the elastic member 240. To assist in retaining the elastic member 240, the retainer 212 includes a first compression member retainer 248, while the adjustment member 208 includes a second compression member retainer 252. The first compression member retainer 248 can be a plurality of fins or an annular ring-shaped member that protrudes away from the tubular portion 228 of the retainer 212. The first compression member retainer 248 can be integrally formed with the retainer 212, or in other embodiments, can be attached to or otherwise connected to the retainer 248. Preferably, the first compression member retainer 248 has a diameter or circumference that is larger than the diameter or circumference of the tubular portion 228 of the retainer 212 but smaller than the inner diameter or inner circumference of the first shaft 22.

[0048] The second compression member retainer 252 can be an annular ring-shaped member that protrudes away from the member 220 of the adjustment member 208. The second compression member retainer 252 can receive the member 220 and forms a connection by means of a screw-like interconnection with a threaded portion. In other embodiments, the second compression member retainer 252 can be integrally formed with the member 220 or can be connected to the member 220 in other ways. Preferably, the second compression retainer 252 has a diameter or circumference that is larger than the diameter or circumference of the member 220 but smaller than the inner diameter or inner circumference of the first shaft 22.

[0049] The adjusting member 208 is held in place relative to the retainer 212 by the second compression member retainer 252, so the biasing member 232 applies tension between the adjusting member 208 and the retainer 212. When the biasing member 232 applies a biasing force, the second compression member retainer 252 contacts the retainer 212 and / or the elastic member 240, resists the biasing force, and generates tension. In other embodiments of the compression assembly 204, the biasing member 232 can apply tension between any suitable portion of the adjusting member 208 and any suitable portion of the retainer 212. For example, the biasing member 232 can be positioned within the second shaft 120 between the adjusting member 208 and the retainer 212. In this example, the adjusting member 208 and the retainer 212 can each include a protrusion that contacts an opposite end of the biasing member 232 and facilitates the application of tension between the adjusting member 208 and the retainer 212. Additionally, in other embodiments, the biasing member 232 can be connected to, or not connected to, one or both of the adjusting member 208 and / or the retainer 212.

[0050] The relative sizing of the first and second compression member retainers 248, 252 with respect to the other components provides retention of the elastic member 240 while also providing for axial sliding of the compression assembly 204 (and the attached second shaft 120) with respect to the first shaft 22. The relative sizing is provided for illustrative purposes. In other embodiments, the elastic member 240 and the compression member retainers 248, 252 can be of any suitable size, shape, or positioning relative to each other, enabling the compression assembly 204 to selectively apply a compressive force between the first shaft 22 and the compression assembly 204 and selectively retain the compression assembly 204, and the attached second shaft 120, by the first shaft 22.

[0051] The compression assembly 204 is adjustable between a first configuration and a second configuration, wherein in the first configuration, as shown in FIGS. 11-13 , the compression assembly 204 applies a selective compressive force to the resilient member 240, and in the second configuration (not shown), the compression assembly 204 does not apply a selective compressive force to the resilient member 240. Specifically, the resilient member 240 has a larger outer diameter in the first configuration than in the second configuration. More specifically, when the compression assembly 204 applies a compressive force to the resilient member 240 in the first configuration, the resilient member 240 expands radially outward from the axial direction of the first and second shafts 22, 120 and engages the first shaft 22. In the second configuration, the compressive force is removed from the resilient member 240, and the resilient member 240 contracts radially inward, returning to a relaxed or normal state. In a relaxed state, the resilient member 240 is sized to permit axial movement within the first shaft 22, or movement in a direction generally parallel to the axis A (shown in FIGS. 1-2), by the compression assembly 204.

[0052] As shown in FIG. 11, the variable length shaft assembly 200 is provided in a first configuration. The biasing member 232 applies a biasing force to the head 216 of the adjustment member 208 in a first direction 256 away from the club head 14. The biasing force pulls the second compression member retainer 252 toward the first compression member retainer 248, reducing the distance between the first compression member retainer 248 and the second compression member retainer 252. The second compression member retainer 252 then applies a compressive force to the elastic member 240, expanding the elastic member 240 radially outward from the compression assembly 204 (and radially outward from the axial directions of the first and second shafts 22, 120) to engage the first shaft 22. When the elastic member 240 expands radially outward between the first shaft 22 and the tubular portion 228 of the retainer 212, the elastic member 240 restricts the axial movement of the retainer 212 relative to the first shaft 22. And since the second shaft 120 is attached to the retainer 212, the elastic member 240 restricts the movement of the second shaft 120 relative to the first shaft 22, and thus the club length of the golf club 10 cannot be adjusted.

[0053] To adjust the club length of the golf club 10, the user inserts a torque wrench into the aperture 46 defined by the grip 34 and engages the torque wrench with the socket 108 of the head 216. The user then applies a force with the torque wrench in a direction 260 opposite to the biasing force direction 256, overcoming the biasing force sufficiently, i.e., it compresses the biasing member 232. As the biasing member 232 compresses, the adjustment member 208 slides within the retainer 212, and more specifically, slides in a second direction 260 toward the club head 14. The head 216 slides within the well 224 in a second direction 260 toward the club head 14, while the second compression member retainer 252 moves away from the first compression member retainer 248, increasing the distance between the first compression member retainer 248 and the second compression member retainer 252.

[0054] Then, the second compression member retainer 252 withdraws the compressive force on the elastic member 240, enabling the elastic member 240 to contract radially inwardly in the axial direction of the first and second shafts 22, 120, and releasing the first shaft 22. When the elastic member 240 is released from the first shaft 22, the first and second shafts 22, 120 can move freely relative to each other, and the user can adjust the club length of the golf club 10. Here, the compression assembly 204 assumes a second configuration, which is not shown.

[0055] More specifically, to adjust the club length of the golf club 10, the user maintains the application of force in the second direction 260 with a torque wrench and then slides the first shaft 22 relative to the second shaft 120. To increase the club length of the golf club 10, the user slides the first shaft 22 away from the second shaft 120 (in the first direction 256), pulling the first shaft 22 out of the second shaft 120. To decrease the club length of the golf club 10, the user slides the first shaft 22 toward the second shaft 120 (in the second direction 260), inserting the first shaft 22 into the second shaft 120. When the first shaft 22 moves axially (either in the first direction 256 or the second direction 260), the attached insert 128 moves with the first shaft 22. Thus, the insert 128 moves in both axial directions along the tubular portion 228 of the retainer 212, and the slot 124 holds and guides the protrusion 132 on the insert 128. This combination aids in adjusting the first shaft 22 relative to the second shaft 120 and increasing or decreasing the club length of the golf club 10, while restricting rotation of the second shaft 120 relative to the first shaft 22 and maintaining the orientation of the grip 34 relative to the club head 14 (i.e., restricting rotation of the grip 34 around the first shaft 22). The adjustment of the club length by sliding the first shaft 22 relative to the second shaft 120 is provided for illustrative purposes, and it should be recognized that either the first or second shaft 22, 120 can be slid relative to the other.

[0056] When the user adjusts the first shaft 22 and / or the second shaft 120 to a desired club length of the golf club 10, the user removes the application of force in the second direction 260 by a torque wrench. This leads to the compression assembly 204 transitioning back from the second configuration to the first configuration. The biasing member 232 applies a biasing force in the first direction 256 to the head 216 of the adjustment member 208, pulling the second compression member retainer 252 toward the first compression member retainer 248. Then, the second compression member retainer 252 applies a compressive force to the elastic member 240, expanding the elastic member 240 radially outwardly to engage the first shaft 22 and restricting the movement of the retainer 212 along the axial direction with respect to the first shaft 22 along axis A (see FIGS. 1-2). And this restricts or minimizes the movement of the second shaft 120 with respect to the first shaft 22, and thus the club length of the golf club 10 cannot be adjusted.

[0057] In the illustrated embodiment, the second shaft includes slots and the insert includes protrusions. In other embodiments, the second shaft can include two or more slots and the insert can include two or more protrusions. The second shaft can have any number of slots, such as one, two, three, four, five, or any other number of slots. The insert can have any number of protrusions corresponding to the number of slots, such as one, two, three, four, five, or any other number of protrusions. For example, the second shaft can include three slots corresponding to three protrusions on the insert, or the second shaft can include four slots corresponding to four protrusions on the insert. In some embodiments, the slots can be positioned equidistantly or asymmetrically around the second shaft. Further, the protrusions can be positioned equidistantly or asymmetrically around the insert.

[0058] In yet other embodiments, the second shaft can include one or more protrusions, and the insert can include one or more slots. In these or other embodiments, the second shaft can have any number of protrusions, such as one, two, three, four, five, or any other number. In these or other embodiments, the insert can have any number of slots corresponding to the number of protrusions, such as one, two, three, four, five, or any other number. For example, the second shaft can include three protrusions corresponding to three slots in the insert, or the second shaft can include four protrusions corresponding to four slots in the insert. In some embodiments, the protrusions can be positioned equidistantly or asymmetrically around the second shaft. Further, the slots can be positioned equidistantly or asymmetrically around the insert.

[0059] Figures 14-19 illustrate a third embodiment of the variable length shaft assembly 300. The assembly 300 has elements in common with assemblies 100, 200, and the common elements are given the same reference numbers. The third embodiment of the assembly 300 includes a cam lock assembly 304, which is disclosed in the following additional detail and selectively adjusts and maintains the length of the golf club 10.

[0060] Referring to FIG. 14, the grip 34 defines an aperture 46 at the second end 50. The aperture 46 provides access to the cam lock assembly 304 (shown in FIGS. 15-17), and more specifically, provides access to an adjustment member 308 (shown in FIG. 16) that carries a socket 108 (shown in FIGS. 15-17). The grip 34 is attached to the second shaft 120 (shown in FIGS. 15-16) but not to the first shaft 22.

[0061] As shown in FIGS. 15 - 16, the first shaft 22 is received by the second shaft 120, enabling the first and second shafts 22, 120 to move axially relative to each other. The insert 128 is fixed to the second end 30 of the first shaft 22 (shown in FIG. 16). Further, the insert 128 includes a protrusion 132 that extends beyond the outer periphery of the first shaft 22. The second shaft 120 includes a slot 124 (shown in FIG. 15) that extends axially along the second shaft 120 in a direction from the second end 116 (shown in FIG. 16) towards the club head 14. The protrusion 132 is fixed to be received by the slot 124.

[0062] As shown in FIG. 16, the variable - length shaft assembly 300 includes an adjustment member 308 and a retainer 312. The adjustment member 308 includes a head or head portion 316 that is connected to a member or shaft portion 320. The member 320 extends into the second shaft 120 away from the head 316. In the illustrated embodiment, the head 316 has a diameter that is generally larger than the diameter of the member 320. However, in other embodiments, the head 316 can have a diameter that is approximately the same size as the diameter of the member 320, or a diameter that is generally smaller than the diameter of the member 320.

[0063] The retainer 312 includes a well 324 that defines a recess leading to a channel or aperture 328 provided through the retainer 312. The retainer 312 is received by the second shaft 120 through the second end 116. In addition, the retainer 312, and more specifically, the well 324, is attached to the second shaft 120 at the second end 116. The retainer 312 does not rotate independently of the second shaft 120 or move in any other way. Instead, the retainer 312 moves with the second shaft 120.

[0064] Retainer 312 slidably receives adjustment member 308, and adjustment member 308 slides independently of retainer 312. More specifically, the recess slidably receives head 316, while channel 328 slidably receives member 320. To facilitate the slidable movement of adjustment member 308 within retainer 312, channel 328 has an inner diameter complementary to the outer diameter of member 320. Similarly, well 324 has an inner diameter complementary to the outer diameter of head 316. The complementary sizes enable adjustment member 308 to slide relative to retainer 312 in the axial direction or in a direction generally parallel to first and second shafts 22, 120.

[0065] Adjustment member 308 is elastically connected to retainer 312 by a biasing member or spring 332. In the illustrated embodiment, biasing member 332 is connected to adjustment member 308, and more specifically, is connected to head 316 of adjustment member 308. Also, biasing member 332 is received by well 324 of retainer 312.

[0066] Insert 128 defines aperture 336. Aperture 336 slidably receives adjustment member 308, and more specifically, slidably receives member 320 of adjustment member 308. Aperture 336 has an inner diameter complementary to the outer diameter of member 320, enabling insert 128 to slide along member 320.

[0067] Referring now to FIG. 17, the cam lock assembly 304 includes a cam member 340 that projects from the adjustment member 308. In the illustrated embodiment, the cam member 340 projects from the head 316. The cam member 340 is received by a slot 344 provided in the retainer 312. The slot 344 includes a first end 348 opposite a second end 352 and is provided at a predetermined angle with respect to an axis A (shown in FIGS. 1-2), and the second end 352 is positioned closer to the second shaft 120 than the first end 348. An offset locking portion or groove 356 communicates with the slot 344. In the illustrated embodiment, the locking portion 356 is provided at the second end 352 of the slot 344 at a predetermined angle with respect to the slot 344. In addition, the locking portion 356 is provided farther from the second end 352 so as to be away from the second shaft 120.

[0068] Referring to FIGS. 16, 18, and 19, insert 128 also includes an extension 360 that extends toward club head 14. Insert 128 defines a channel 364 by extension 360, and channel 364 receives adjustment member 308, and more specifically, member 320 that forms cam portion 368. Channel 364 has a geometry that allows adjustment member 308 and associated cam portion 368 to slide within channel 364 when cam lock assembly 304 is in a first configuration or unlocked configuration, and does not allow adjustment member 308 and associated cam portion 368 to slide within channel 364 when cam lock assembly 304 is in a second configuration or locked configuration. Adjustment member 308 is held in place relative to retainer 312 by cam portion 368, so biasing member 332 applies tension between adjustment member 308 and retainer 312. When biasing member 332 applies a biasing force, cam portion 368 contacts channel 364 and / or insert 128, resists the biasing force, and generates tension. In other embodiments of variable length shaft assembly 300, biasing member 332 can apply tension between any suitable portion of adjustment member 308 and any suitable portion of retainer 312. In this example, adjustment member 308 and retainer 312 can each include a protrusion within second shaft 120, and the protrusions contact opposite ends of biasing member 332 to facilitate the application of tension between adjustment member 308 and retainer 312. Additionally, in other embodiments, biasing member 332 can be connected to or not connected to one or both of adjustment member 308 and / or retainer 312.

[0069] FIG. 18 illustrates the adjustment member 308 and associated cam portion 368 in the first configuration or unlocked configuration. The channel 364 has a geometry complementary to the cam portion 368, and the cam portion 368 can slide freely within the channel 364. The first and second shafts 22, 120 are freely movable relative to each other to enable adjustment of the club length of the golf club 10.

[0070] FIG. 19 illustrates the adjustment member 308 and associated cam portion 368 in the second configuration or locked configuration. As the cam portion 368 moves from the first configuration to the second configuration, the channel 364 has opposing cam surfaces 372 that respectively engage the cam portion 368 to form a friction fit or press fit or interference fit. The friction fit holds the adjustment member 308 relative to the insert 128. This locks the second shaft 120 (connected to the adjustment member 308 by the retainer 312) to the first shaft 22 (connected to the insert 128) and restricts adjustment of the club length of the golf club 10. The illustrated embodiments of the channel 364 and cam portion 368 are generally shown with an oval cross-sectional shape, but in other embodiments, the channel 364 and cam portion 368 can have any suitable complementary geometry that allows sliding movement of the cam portion 368 within the channel 364 in the unlocked configuration and prevents sliding movement of the cam portion 368 within the channel 364 by forming a friction fit between the cam portion 368 and one or more cam surfaces 372 in the locked configuration.

[0071] As shown in FIGS. 15 - 18, the variable length shaft assembly 300 is provided in a first configuration or an unlocked configuration. The cam lock assembly 304 is in an unlocked configuration, and the cam member 340 is positioned within the slot 344 proximal to the first end 348. To assist in maintaining the cam member 340 in the unlocked configuration, the biasing member 332 uses the well 324 to apply a biasing force in a first direction 376 (shown in FIG. 16) away from the club head 14 to the head 316 of the adjustment member 308. The cam portion 368 of the adjustment member is fixed or aligned with the channel 364 of the insert 128, allowing the cam portion 368 to slide within the channel 364. And the second shaft 120 carries the adjustment member 308 by a retainer 312 that is attached, and the second shaft 120 is movable relative to the first shaft 22, which carries the insert 128. Thus, in the unlocked configuration, the first and second shafts 22, 120 are axially moved relative to each other, enabling adjustment of the club length of the golf club 10.

[0072] To adjust the club length of the golf club 10, the user can axially slide the first shaft 22 relative to the second shaft 120. To decrease the club length of the golf club 10, the user slides the first shaft 22 toward the second shaft 120 (in the first direction 376) and further inserts the first shaft 22 into the second shaft 120. To increase the club length of the golf club 10, the user slides the first shaft 22 away from the second shaft 120 (in the second direction 380 shown in FIG. 16) and pulls the first shaft 22 out of the second shaft 120. When the first shaft 22 moves axially (either in the first direction 376 or the second direction 380), the attached insert 128 moves with the first shaft 22. Thus, the insert 128 moves axially along the member 320 of the adjusting member 308 by the aperture 336, the cam portion 368 moves axially within the channel 364 defined by the insert 128, and the slot 124 in the second shaft 120 holds and guides the protrusion 132 on the insert 128. This combination assists in adjusting the first shaft 22 relative to the second shaft 120 and increasing or decreasing the club length of the golf club 10. The protrusion 132, which is fixed to slide within the slot 124, limits the rotation of the second shaft 120 relative to the first shaft 22 and maintains the orientation of the grip 34 relative to the club head 14.

[0073] When the user adjusts the first shaft 22 and / or the second shaft 120 to the desired club length of the golf club 10, the user shifts the cam lock assembly 304 from the unlocked configuration to the locked configuration. The user inserts a torque wrench into the aperture 46 defined by the grip 34 and engages the torque wrench with the socket 108 of the head 316. The user then applies a rotational force to the torque wrench in a first rotational direction, which is clockwise in the illustrated embodiment. Rotation of the torque wrench in the first rotational direction rotates the head 316, the attached cam member 340, and the adjustment member 308 as a whole.

[0074] During rotation, the cam member 340 slides along the slot 344 and moves from the first end 348 towards the second end 352. The slot 344 converts the rotational force from the torque wrench into a linear force, which overcomes the biasing force applied by the biasing member 332. This results in the adjustment member 308 sliding along the axis A (shown in FIGS. 1 - 2) in a second direction 380 (towards the club head 14) relative to both the retainer 312 and the insert 128. The cam portion 368 rotates simultaneously in the channel 364 from the unlocked configuration (shown in FIG. 18) towards the locked configuration (shown in FIG. 19), and one or more cam surfaces 372 of the channel 364 engage the cam portion 368.

[0075] Referring to FIG. 17, when the cam member 340 reaches the second end 352 of the slot 344, continued rotation of the torque wrench in the first rotational direction guides the cam member 340 into the locking portion 356 offset from the slot 348. When the cam member 340 is received within the locking portion 356, the user can no longer rotate the adjustment member 308 by the head 316. The biasing force applied to the head 316 by the biasing member 332 in the first direction 376 (shown in FIG. 16) maintains the cam member 340 within the locking portion 356. Here, the cam lock assembly 308 is in a locked configuration. In addition, one or more cam surfaces 372 of the channel 364 engage the cam portion 368 to form a friction fit that locks the adjustment member 308 (and the second shaft 120 to be attached) within the channel 364 defined by the insert 128 (and the attached first shaft 22). In the locked configuration, relative movement of the first shaft 22 and the second shaft 120 is restricted or minimized, and thus the club length of the golf club 10 cannot be adjusted. The user can freely withdraw the torque wrench from the socket 108 of the head 316.

[0076] To shift the cam lock assembly 304 from the locked configuration to the unlocked configuration, the user inserts a torque wrench into the socket 208 and applies a torsional force and a downward force in a second direction 380 (or toward the club head 14), overcoming the biasing force applied to the head 316 by the biasing member 332. While applying a downward force to the head 316, the user rotates the torque wrench in a second rotational direction, which is counterclockwise in the illustrated embodiment. This releases the cam member 340 from the locking portion 356 and moves the cam member 340 toward the second end 352 of the slot 344. Continued rotation in the second rotational direction further rotates the head 316 and moves the cam member 340 along the slot 344 from the second end 352 to the first end 348. It should be appreciated that the biasing force applied to the head 316 by the biasing member 332 contributes to moving the cam member 340 to the first end 348 of the slot 344. As the head 316 rotates, the cam portion 368 rotates within the channel 364 about the insert 124 from the locked configuration (shown in FIG. 19) toward the unlocked configuration (shown in FIG. 18), and one or more cam surfaces 372 of the channel 364 disengage the cam portion 368. When the cam member 340 reaches the first end 348 of the slot 344 (shown in FIG. 17), the cam lock assembly 304 is in the unlocked configuration. In this unlocked configuration, the club length of the golf club 10 can be freely adjusted as previously described.

[0077] It should be recognized that the geometry of the cam lock assembly 304, and more particularly the geometry of the slot 344 and associated offset locking portion 356, is provided for illustrative purposes. In other embodiments, the geometry can be adjusted while maintaining the same function. For example, in order to rotate the adjustment member 308 from the unlocked configuration to the locked configuration, the user can rotate a torque wrench in a first rotational direction, where the first rotational direction can be a counterclockwise rotation of the torque wrench, such that the geometry is such. Similarly, in order to rotate the adjustment member 308 from the locked configuration to the unlocked configuration, the user rotates the torque wrench in a second rotational direction, where the second rotational direction is a clockwise rotation of the torque wrench.

[0078] Also, in other embodiments, it should be recognized that aspects of the variable length shaft assembly 300 can be modified, added, or removed while selectively adjusting and continuing to maintain the length of the golf club 10. For example, in one embodiment of the variable length shaft assembly 300, the cam lock assembly 304 does not include a biasing member 332, a cam member 340, or a slot 344. Instead, the cam lock assembly 304 includes a cam portion 368 that rotates within the channel 364 between an unlocked configuration (shown in FIG. 18) and a locked configuration (shown in FIG. 19), as previously described in other ways.

[0079] In another embodiment of the variable length shaft assembly 300, the biasing member 332, the cam member 340, and the slot 344 of the cam lock assembly 304 are replaced by a plurality of threaded portions that extend around the outer or peripheral portion of the head 316, and the plurality of threaded portions engage threaded portions that extend around a recess defined by the well 324. Rotation of the head 316 forms a translational movement of the adjustment member 308 in the axial direction.

[0080] In another embodiment of the variable length shaft assembly 300, the slot 344 is positioned perpendicular to the axis A (shown in FIGS. 1-2) and defines the limits of movement with respect to the head 316. Thus, rotation of the head 316 results in rotation of the adjustment member 308, but does not result in translational movement.

[0081] FIGS. 24-27 illustrate a fourth embodiment of the variable length shaft assembly 500. The assembly 500 has elements in common with the assembly 100, and the common elements are given the same reference numerals.

[0082] Referring to FIGS. 24-25, the screw head 104 is received by the retainer 112, which is stationary with respect to the second shaft 120 but allows rotation of the screw head 104. The second shaft 120 includes an inner surface 122 that is configured to receive the outer surface 130 of the insert 128. Neither the second shaft 120 nor the insert has slots and protrusions (see FIGS. 26-27).

[0083] Referring to FIGS. 26-27, the inner surface 122 of the second shaft 22 includes a substantially hexagonal cross-sectional shape. The outer surface 130 of the insert 128 includes a substantially hexagonal cross-sectional shape corresponding to the inner surface 122 of the second shaft 120. The cross-sectional shape of the inner surface 122 of the second shaft 120 and the outer surface 130 of the insert limit the rotation of the second shaft 120 with respect to the first shaft 22, similar to the slots 124 and protrusions 132 in the first embodiment of the variable length shaft assembly 100.

[0084] In the illustrated embodiment, the inner surface 122 of the second shaft 120 and the outer surface 130 of the insert 128 are substantially hexagonal in cross-sectional shape. In other embodiments, the cross-sectional shape of the inner surface 122 of the second shaft 120 and the outer surface 130 of the insert can be any shape that can restrict rotational movement between the second shaft 120 and the insert 128. For example, the cross-sectional shape of the inner surface 122 of the second shaft 120 and the outer surface 130 of the insert 128 can be a polygon or a shape having at least one curved surface, such as a semi-circular shape, a triangular shape, a square shape, a rectangular shape, a pentagonal shape, a hexagonal shape, or any other shape.

[0085] Referring to FIG. 25, the second shaft 120 further includes one or more tabs 126. The tabs 126 are angled towards the first shaft 22 and provide a snug fit between the second shaft 120 and the first shaft 22. In the illustrated embodiment, the second shaft 120 includes three tabs 126. Each of the three tabs 126 is spaced equidistant from each other. In other embodiments, the second shaft 120 can include any number of tabs 126. For example, the second shaft 120 can include one, two, three, four, five, or any other number of tabs 126.

[0086] Furthermore, in other embodiments, the second shaft 120 can include, in addition to or instead of the tab 126, a gasket. The second shaft 120 can have one or more grooves (171) for receiving the gasket 170. The second shaft 120 can have one, two, three, or four grooves (171) for receiving the gasket 170. The gasket 170 can be made of rubber, polyurethane, a polymeric material, or any other material that can provide a tight fit between the first shaft 22 and the second shaft 120 (FIG. 28). Further, the second shaft 120 having the gasket 170 can move along the length of the threaded screw 140, but limits lateral movement between the first shaft 22 and the second shaft 120.

[0087] Furthermore, in other embodiments, the second shaft 120 can include an overmolded section, and the overmolded section provides a tight fit between the second shaft 120 and the first shaft 22 (not shown). The second shaft 120 can have an overmolded section within 0.5 inches, 1.0 inches, 1.5 inches, 2.0 inches, or 2.5 inches of the bottom of the second shaft 120. This overmolded section can include a polymeric material, rubber, a rubber-like material, or any other material that can provide a tight fit between the first shaft 22 and the second shaft 120 (not shown). Further, the second shaft 120 having the overmolded section can move along the length of the threaded screw 140 and limits lateral movement between the first shaft 22 and the second shaft 120.

[0088] The variable length shaft assembly 500 described herein may be operated in the same manner as the variable length shaft assembly 100 described above, and restricting the rotational movement of the first shaft 22 relative to the second shaft 120 is achieved by the cross-sectional shapes of the inner surface 122 of the second shaft 120 and the outer surface 130 of the insert 128, instead of the slot and protrusion mechanism.

[0089] Figures 30 - 38 show a fifth embodiment of the variable length shaft assembly 800. The assembly 800 has elements common to the assemblies 100 and 500, and the common elements are given the same reference numerals.

[0090] Referring to FIGS. 31 - 34, the screw head 104 is received by a retainer 812 that is stationary relative to the second shaft 120 but allows rotation of the screw head 104. The retainer 812 itself is received by the second end or abutting end 116 of the second shaft 120. The second shaft 120 further includes a first end 118 opposite the second end 116. The second shaft 120 includes an inner surface 122 configured to receive the outer surface 114 of the retainer 812.

[0091] In the illustrated embodiment, the retainer 812 includes two semi-circular pieces. The two pieces of the retainer 812 snap fit into the second end 116 of the second shaft 120 to improve the concentricity of the threaded screw 140 within the second shaft 120. The improved concentricity better aligns the first shaft 22 within the second shaft 120. To achieve the improved concentricity, the outer surface 114 of the retainer 812 further includes one or more pegs 818. The one or more pegs 818 extend outwardly from the outer surface 114 of the retainer 812 and are configured to be received by one or more apertures 820 disposed on the second shaft 120. The interlocking shape between the peg 818 and the aperture 820 allows the retainer 812 to remain stationary with respect to the second shaft 120 while allowing rotation of the screw head 104.

[0092] The inner surface 122 of the second shaft 120 includes a substantially hexagonal cross-sectional shape. The outer surface 114 of the retainer 812 includes a substantially hexagonal cross-sectional shape corresponding to the inner surface 122 of the second shaft 120. The cross-sectional shapes of the inner surface 122 of the second shaft 120 and the outer surface 114 of the retainer 812 allow the retainer 812 to remain stationary within the second shaft 120 while still allowing the threaded screw 140 to rotate.

[0093] In other embodiments, the cross-sectional shape of the outer surface 114 of the retainer 812 can be any shape that can allow the retainer 812 to remain stationary within the second shaft 120. For example, the cross-sectional shape of the outer surface 114 of the retainer 812 can be a polygon or a shape with at least one curved surface such as a semi-circular, triangular, square, rectangular, pentagonal, hexagonal, or any other shape.

[0094] Furthermore, as shown in FIGS. 32 and 34, the outer surface 114 of the retainer 812 includes a plurality of knob-shaped protrusions 814. The knob-shaped protrusions 814 extend outwardly from the outer surface 114 of the retainer 812. The knob-shaped protrusions 814 can be dot-shaped protrusions or projections that extend outwardly from the outer surface 114 of the retainer 812. The knob-shaped protrusions 814 are configured to abut or press against the inner surface 122 of the second shaft 120. The knob-shaped protrusions 814 provide a tight fit between the retainer 112 and the second shaft 120. The knob-shaped protrusions 814 further improve the concentricity of the threaded screw 140 within the second shaft 120.

[0095] As shown in FIG. 34, the retainer 812 includes an axial end face 816. The axial end face 816 of the retainer 812 is adjacent to the second end 116 of the second shaft 120. The retainer 812 further includes an axial length measured from the axial end face 816 of the retainer in the direction from the second end 116 to the first end 118 of the second shaft 120. In some embodiments, the knob-shaped protrusions 814 can be located near the axial end face 816 of the retainer. In other embodiments, the knob-shaped protrusions 814 can be located away from the axial end face 816 of the retainer. The knob-shaped protrusions 814 of the retainer 812 can be positioned at a location that is at least 25% of the axial length of the retainer 812. In other embodiments, the knob-shaped protrusions 814 of the retainer 812 can be positioned at a location that is at least 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80% of the axial length of the retainer 812. In still other embodiments, the knob-shaped protrusions 814 of the retainer 812 can be positioned on at least one side of the hexagonal retainer 812. In other embodiments, the knob-shaped protrusions 814 of the retainer 812 can be positioned on one, two, three, four, five, or six sides of the hexagonal retainer 812.

[0096] The knob-shaped protrusion 814 can include a substantially spherical shape. In other embodiments, the knob-shaped protrusion 814 can be any shape that can abut or press against the inner surface 122 of the second shaft 120. For example, the shape of the knob-shaped protrusion 814 can be a semi-circle or shape with at least one curved surface, such as a hemisphere, a cylinder, a triangle, a square, a rectangle, a pentagon, a hexagon, a polygon, or any other shape.

[0097] In the illustrated embodiment, the outer surface 114 of the retainer 812 includes eight knob-shaped protrusions 814, where two knob-shaped protrusions 814 are positioned on the sides of the hexagonal retainer 812. In other embodiments, the retainer 812 can include any number of knob-shaped protrusions 814. For example, the retainer 812 can include from 4 to 24, from 4 to 18, or from 4 to 12 knob-shaped protrusions 814. In other examples, the retainer 812 can include 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 knob-shaped protrusions 814.

[0098] Figures 34 - 36 depict an insert 828 received within the second end 30 of the first shaft 22. The insert 828 also defines a threaded aperture 136 and a tubular portion 836 without threads. The inner surface 122 of the second shaft 120 is configured to receive the outer surface 130 of the insert 828. The insert 128 is configured to be coupled, attached, or fixed to the second end 30 of the first shaft 22. The outer surface 130 of the insert 828 is configured to be coupled, attached, or fixed to the inner surface 24 of the first shaft 22 at the second end 30. In other words, the insert 828 is coupled, attached, or fixed to the end face or axial end face 32 of the first shaft 22. The insert 828 can be coupled, attached, or fixed to the first shaft 22 by an adhesive, epoxy, glue, or any other suitable adhesive. In some embodiments, the insert 828 is permanently coupled, attached, or fixed to the axial end face 32 of the first shaft 22.

[0099] Insert 828 defines a first axially facing end surface 838 and a second axially facing end surface 840. The first axially facing end surface 838 is located near the second end 116 of the second shaft 120. The second axially facing end surface 840 is located near the first end 118 of the second shaft 120. Insert 828 extends into a portion of the first shaft 22 and engages the first shaft 22, where the second axially facing end surface 840 is located within the first shaft 22. The engagement between insert 828 and the first shaft 22 defines an engagement length. The engagement length is defined as the axial length between the axially facing end surface 32 of the first shaft 32 and the second axially facing end surface 840 of insert 828. The engagement length between insert 828 and the first shaft 22 improves the stiffness of the variable shaft length assembly 800, thereby restricting lateral or radial movement between the first shaft 22 and the second shaft 120 during operation of the variable shaft length assembly 800. Insert 828 engages a larger portion of the first shaft 22 and can improve the alignment of the first shaft 22 within the second shaft 120. Good alignment of the first shaft 22 reduces misalignment, thereby allowing the first shaft 22 to translate freely without interfering with the second shaft 120.

[0100] In the illustrated embodiment, the engagement length between insert 828 and the first shaft 22 is 5.0 inches. In other embodiments, the engagement length can be between 2 and 10 inches. In other embodiments, the engagement length can be between 2 and 5 or 5 and 10 inches. In still other embodiments, the engagement length can be between 2 and 6, 3 and 7, 4 and 8, 5 and 9, or 6 and 10 inches. For example, the engagement length can be 2, 3, 4, 5, 6, 7, 8, 9, or 10 inches.

[0101] Referring to FIG. 33, the outer surface 130 of the insert 828 includes a substantially hexagonal cross-sectional shape. As described above, the inner surface 122 of the second shaft 120 includes a hexagonal cross-sectional shape. The outer surface 130 of the insert 128 corresponds to the inner surface 122 of the second shaft 120. The cross-sectional shapes of the inner surface 122 of the second shaft 120 and the outer surface 130 of the insert 828 limit the rotation of the second shaft 120 relative to the first shaft 22. Limiting the rotation of the second shaft 120 relative to the first shaft 22 by the cross-sectional shape can be similar to the way the slots 124 and protrusions 132 of the variable length shaft assembly 100 limit the rotation of the second shaft 120 relative to the first shaft 22.

[0102] In the illustrated embodiment, the inner surface 122 of the second shaft 120 and the outer surface 130 of the insert 828 are of a substantially hexagonal cross-sectional shape. In other embodiments, the cross-sectional shapes of the inner surface 122 of the second shaft 120 and the outer surface of the insert can be any shape capable of restricting rotational movement between the second shaft 120 and the insert 828. For example, the cross-sectional shapes of the inner surface 122 of the second shaft 120 and the outer surface 130 of the insert 828 can be a polygon or shape with at least one curved surface, such as a semi-circle, triangle, square, rectangle, pentagon, hexagon, or any other shape.

[0103] Referring to FIGS. 34 and 38, the outer surface 130 of the insert 828 further includes a plurality of bump-like protrusions 832. The bump-like protrusions 832 of the insert 828 can be similar to the bump-like protrusions 814 of the retainer 812. The bump-like protrusions can be dot-like protrusions or protrusions extending outwardly from the outer surface 130 of the insert 828. The bump-like protrusions 832 are configured to abut or press against the inner surface 122 of the second shaft 120. The bump-like protrusions 832 provide a tight fit between the insert 828 and the second shaft 120. Further, the bump-like protrusions 832 are configured to abut or press against the inner surface 24 of the first shaft 22. The bump-like protrusions 832 of the insert 828 provide a good bonding range by allowing the adhesive to collect between the bump-like protrusions 832.

[0104] The bump-like protrusions 832 can include a substantially spherical shape. The bump-like protrusions 832 of the insert 828 can include a shape similar to the bump-like protrusions 814 of the retainer 812. In other embodiments, the bump-like protrusions 832 can be of any shape that can abut or press against the inner surface 122 of the second shaft 120. For example, the shape of the bump-like protrusions 832 can be a semi-circle or a shape having at least one curved surface, such as a hemisphere, a cylindrical shape, a triangular shape, a square shape, a rectangular shape, a pentagonal shape, a hexagonal shape, a polygonal shape, or any other shape.

[0105] In the illustrated embodiment, the outer surface 130 of the insert 828 includes 60 bump-like protrusions 832, where 24 bump-like protrusions 832 press against or abut the inner surface 122 of the second shaft 120, and 36 bump-like protrusions 832 abut or press against the inner surface 24 of the first shaft 22. In other embodiments, the insert 828 can include any number of bump-like protrusions 832. For example, the insert 828 can include 10 to 100, 10 to 90, 10 to 80, 10 to 70, or 10 to 60 bump-like protrusions 832. In other examples, the insert 828 can include 10 to 50, 20 to 60, 30 to 70, 40 to 80, 50 to 90, or 60 to 100 bump-like protrusions 832. In still other examples, the insert 828 can include 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 bump-like protrusions 832.

[0106] Furthermore, the bump-like protrusion 832 can include a height. The height of the bump-like protrusion 832 is measured in a direction perpendicular to the outer surface 130 of the insert 828 from the outer surface 130 of the insert 828 to the apex of the bump-like protrusion 832. The height of the bump-like protrusion 832 of the insert 828 and the height of the bump-like protrusion 814 of the retainer 812 can be similar. The height of the bump-like protrusion 832 can be in the range of 0.005 to 0.015 inches. In some embodiments, the height of the bump-like protrusion 832 can be in the range of 0.005 to 0.01 inches, or 0.01 to 0.015 inches. For example, the height of the bump-like protrusion 832 can be 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, 0.011, 0.012, 0.013, 0.014, or 0.015 inches. In one example, the height of the bump-like protrusion 832 is 0.01 inches.

[0107] Referring to FIG. 38, insert 828 also includes an inner surface 138. Insert 828 can further include one or more ribs 834 positioned on inner surface 138 of insert 828. One or more ribs 834 can be positioned on inner surface 138 within tubular portion 836 of insert 828. Ribs 834 extend outwardly from inner surface 138 of insert 828. Ribs 834 extend along tubular portion 836 in a direction from first axial end face 838 to second axial end face 840. Ribs 834 provide a snug fit between screw 140 with threads and insert 828. In the illustrated embodiment, insert 828 includes three ribs 834. Each of ribs 834 is spaced equidistantly from one another. In other embodiments, insert 828 can include any number of ribs 834. For example, insert 828 can include one, two, three, four, five, six, seven, eight, nine, or ten ribs 834. As described in more detail below, ribs 834 provide a tight fit between screw 140 with threads and insert 828. Screw 140 with threads is configured to engage ribs 834 and minimize lateral or radial movement between first shaft 22 and second shaft 120.

[0108] Furthermore, rib 834 can include a height. The height of rib 834 is measured in a direction perpendicular to the inner surface 138 of insert 828 from the inner surface 138 to the apex of rib 834. The height of rib 834 is measured from the inner surface 138 in a radially inward direction to a center line extending through threaded aperture 136 and tubular portion 836 of insert 828. The height of rib 834 can be in the range of 0.001 to 0.01 inches. In some embodiments, the height of rib 834 can be in the range of 0.001 to 0.005 inches, or 0.005 to 0.01 inches. For example, the height of rib 834 can be 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, or 0.01 inches. In one example, the height of rib 834 is 0.005 inches.

[0109] Referring to FIGS. 35 and 37, variable shaft length assembly 800 further includes alignment member 844. Alignment member 844 is positioned at the first end 118 of second shaft 120. The first end 118 is on the opposite side of the second end 116 of second shaft 120. Alignment member 844 includes one or more protrusions 848. One or more protrusions 848 extend away from the alignment member and are configured to be received by one or more apertures 820 disposed on second shaft 120. Protrusion 848 is configured to mechanically interlock with aperture 820. Protrusion 848 fixes the position of alignment member 844 within second shaft 120. Alignment member 844 does not move or translate within second shaft 120 during operation of variable shaft length assembly 800. Alignment member 844 minimizes lateral or radial movement of first shaft 22 within second shaft 120 during operation of variable shaft length assembly 800. Alignment member 844 minimizes misalignment of the first shaft within the second shaft 120, thereby allowing the first shaft 22 to translate freely without interfering with the second shaft 120 during operation of variable shaft length assembly 800.

[0110] The aperture 136 with a threaded portion of the insert 828 receives the screw 140 with a threaded portion. The screw 140 with a threaded portion is configured to have an engaging engagement with the aperture 136 with a threaded portion. As described above with respect to the variable shaft length assembly 100, the engaging engagement between the screw 140 with a threaded portion and the aperture 136 with a threaded portion allows the first shaft 22 and the second shaft 120 to move axially relative to each other and temporarily lock the variable shaft length assembly axially when not in use.

[0111] During operation of the variable length shaft assembly 800, the threaded portion of the screw 140 meshes with the threaded portion of the aperture 136 of the insert 828. As the insert 828 and the first shaft 22 move toward the second end 116, the screw 140 with a threaded portion overlaps a portion of the tubular portion 836 of the insert 828. The threaded portion of the screw 140 meshes with one or more ribs 834 to provide a secure fit between the insert 828 and the screw 140 with a threaded portion. The threaded portion of the screw 140 intrudes into one or more ribs 834. The intrusion operation between the screw 140 with a threaded portion and the rib 834 is achieved by the diameter of the screw 140 with a threaded portion and the aperture diameter between one or more ribs 834.

[0112] In the illustrated embodiment, the diameter of the screw 140 with a threaded portion is larger than the diameter of the opening between one or more ribs 834. In the illustrated embodiment, the diameter of the screw 140 with a threaded portion is 0.25 inches, and the diameter of the opening between one or more ribs 834 is 0.242 inches. However, the diameter of the screw 140 with a threaded portion and the opening between one or more ribs 834 is not limited, and it can be any diameter suitable for the screw 140 with a threaded portion to penetrate one or more ribs 834. The penetration operation between the screw 140 with a threaded portion and one or more ribs 834 provides a tight fit by minimizing the lateral or radial movement of the first shaft 22 within the second shaft 120.

[0113] The variable shaft length assembly 800 described herein can be operated in the same manner as the variable shaft length assemblies 100 or 500 described above, and restricting the rotational movement of the first shaft 22 relative to the second shaft 120 is achieved, similar to the variable length shaft assembly 500, by the cross-sectional shapes of the inner surface 122 of the second shaft 120 and the outer surface 130 of the insert 128.

[0114] FIG. 20 illustrates an embodiment of the adjustable mass assembly 400. In the illustrated embodiment, the grip 34 is attached to the shaft 22, and the shaft 22 contains the mass 404. The mass 404 is attached to an adjustment assembly 408, and the adjustment assembly 408 provides for axial movement of the mass 404 within or along the shaft 22 (or along the axis A shown in FIG. 1) while locking the mass 404 in a desired position. The adjustment assembly 408 can be any suitable assembly for moving the mass 404 within the shaft 22, as further described below.

[0115] Mass 404 is a one-piece weighted material, which can include rubber, metal, metal alloy, composite material, polyurethane, reinforced polyurethane, or any other suitable material or combination of materials. As long as Mass 404 fits within shaft 2 and is movable within shaft 22, Mass 404 can be of any suitable size. Mass 404 can be of any suitable or desired weight, which can include, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more than 20 grams. Mass 404 can be removable from shaft 22 and can be replaceable with a second Mass 404 having different weights, sizes, shapes, or combinations thereof.

[0116] In one or more examples of embodiments, Mass 404 can include a plurality of Masses 404 having the same or different weights, sizes, shapes, or combinations thereof. For example, the plurality of Masses 404 can be arranged axially or laminated within shaft 22. As another example, the plurality of Masses 404 can be in a radially offset arrangement within shaft 22. In still further embodiments, Mass 404 can incorporate a flexible material, which allows for axial movement of Mass 404 within shaft 22 having different or variable shaft diameters, and as a result, reduces the impact on shaft rigidity.

[0117] In yet another embodiment, Mass 404 can be defined by a plurality of separate shaft sections that together define shaft 22. One or more sections can be replaceable or interchangeable with sections having different masses (e.g., sections having a larger mass or a smaller mass). The sections can be connected together to define club shaft 22.

[0118] Referring now to FIG. 21, an embodiment of an adjustable weight assembly 400 is illustrated. In the embodiment, adjustment assembly 408 includes components of variable length shaft assembly 100, and common elements are given the same reference numbers.

[0119] Adjustment assembly 408 includes screw head 104, which is received by retainer 112 and is stationary relative to shaft 22. Retainer 112 is itself received by the second or abutting end 30 of shaft 22. Shaft 22 includes slot or cutout 124, which extends axially along axis A (shown in FIGS. 1 - 2) in a direction from the second end 30 toward club head 14. Slot 124 extends axially along any desired distance or length of shaft 22.

[0120] Weight 404 is received within shaft 22 and includes projection 132, which projects away from weight 404 and is fixed to be received by slot 124. Weight 404 also defines threaded aperture 136. Threaded aperture 136 receives corresponding threaded screw 140, which extends away from screw head 104. Grip 34 is attached to shaft 22.

[0121] During operation of the adjustable mass assembly 400, the user engages a torque wrench with the socket 108 of the screw head 104. To adjust the position of the mass 404 within the shaft 22, the user rotates the torque wrench in a first direction, rotating the screw head 104 and associated screw 140 within the retainer 112. The threaded portion of the screw 140 engages the threaded portion of the aperture 136 within the mass 404. The protrusion 132 fixes the rotational position of the mass 404 relative to the shaft 22, and rotation of the screw 140 drives the mass 404 axially along the slot 124. As the screw 140 rotates in the first direction, the mass 404 is driven away from the second end 30. Alternatively, the user rotates the torque wrench in a second direction opposite the first direction, moving the mass 404 within the shaft 22 toward the second end 30. When the desired position of the mass 404 within the shaft 22 is obtained, the user removes the torque wrench from the screw head 104.

[0122] In another embodiment of the adjustable mass assembly 400 (similar to FIG. 21), the slot 124 is replaced with an axial rail within the interior of the shaft 22, increasing the axial travel distance of the mass 404 within the shaft 22. Instead of the protrusion 132, the mass 404 may be fixed to the rail. The rail fixes the rotational position of the mass 404 relative to the shaft 22 and drives the mass 404 axially in response to rotation of the screw 140. The rail can provide the shaft 22 with a greater structural rigidity than the slot 124, while extending axially along a greater length of the shaft 22 and also providing a greater mass 404 adjustment distance within the shaft 22.

[0123] Figure 29 illustrates another embodiment of a golf club shaft having an adjustable mass assembly 400. In the illustrated embodiment, the adjustable mass assembly 400 includes an adjustable mass 404, which is shown as an internal screw located at the butted portion of the shaft 22 or at the end of the grip 34. The adjustable mass 404 includes a threaded body portion 410 and a screw head 412. The threaded body portion 410 is received within a screw nut 414.

[0124] The screw nut 414 has an inner surface threaded portion that meshes and engages with the threaded body portion 410 of the mass 404. The threaded portion of the inner surface 416 of the screw nut 414 guides the mass 404 to move axially relative to the shaft 22 when the mass 404 is rotated. The screw nut 414 further includes an outer surface 418, which is attached to the inner surface 416 of the shaft 22 at a fixed location along the shaft 22. The screw nut 414 can be attached to the inner surface of the shaft 22 by an adhesive such as epoxy, glue, or tape.

[0125] The screw head 412 of the mass 404 includes a socket 108 that is exposed at an aperture 46 at the mating portion of the shaft 22. A torque wrench 150 can be inserted through the aperture 46 into the socket 108 of the screw head 412 to adjust the position of the mass 404 within the shaft 22. Rotating the torque wrench 150 in a clockwise motion will shift the mass 404 downward along the shaft 22 or closer to the club head. Similarly, rotating the torque wrench 150 in a counterclockwise motion will shift the mass 404 upward along the shaft 22 or closer to the mating portion. Shifting the mass 404 affects the moment of inertia and swing weight of the golf club 10. The distance and weight of the mass 404 shift per rotation of the torque wrench 150 depends on the pitch of the threaded body portion 410. For example, for a mass 404 having a weight of 4 grams, rotating the torque wrench 150 five rotations will shift the mass 404 by 1.25 inches and change the swing weight by 0.1. In another example, for a mass 404 having a weight of 8 grams, rotating the torque wrench 150 two and a half rotations will shift the mass 404 by 1.25 inches and change the swing weight by 0.1.

[0126] In one example, the mass 404 has a weight of 4 grams and includes an additional weight of 2 grams positioned within the club head 14 so as to be counter-balanced within the golf club 10. The counter-balance for the adjustable mass 404 within the butt portion of the shaft relative to the club head 14 is in a ratio of approximately 2:1, such that for every 2 grams of weight added to the butt portion of the shaft, an additional 1 gram must be added to the club head 14. In other embodiments, the adjustable mass 404 within the butt portion of the shaft 22 can have a weight of 6 grams and the club head 14 can have a weight of 3 grams. This 2:1 counter-balance ratio will help to maintain the same swing weight of the golf club.

[0127] In other embodiments, the adjustment assembly 408 can incorporate components and aspects of the variable length shaft assemblies 200, 300 to adjust the position and hold the mass 404 within the shaft 22. For example, the mass 404 can be formed from, or can include, an elastic material that can be deformed to hold the mass 404 in a desired position within the shaft 22. As another example, the mass 404 can include a cam portion 368 that rotates within a channel 364 within the shaft, and the cam portion 368 rotates between a position where the mass 404 can be axially moved within the shaft 22 and a different position where the cam portion 368 engages one or more cam surfaces 372 to hold the mass 404 in a desired position within the shaft 22. In these examples of embodiments, the mass 404 can be fixed to the axial slot 134 or positioned at the end of the member 320, such that the distance by which the mass 404 can be axially adjusted within the shaft 22 can be limited to be less than the overall length of the shaft **********

[0128] In other embodiments, aspects of the adjustable mass assembly 400 can be incorporated into the golf club 10 in combination with the variable length shaft assemblies 100, 200, 300 disclosed above. For example, each variable length shaft assembly 100, 200, 300 has a nested screw assembly and can separately adjust the shaft length and the position of the mass 404 within the shaft.

[0129] As an example, the screw head 104 and screw 140 of the variable length shaft assembly 100 can receive a nested second screw (not shown). Rotation of the screw 140 adjusts the club length, while rotation of only the second screw adjusts the position of the mass 404 within the club shaft. Generally, the screw head 104 is received within the well 224 and the biasing member applies a biasing force to the screw head 104 in directions 256, 376 away from the retainer 112. When biased, the screw 140 and the second screw can rotate together to adjust the club length. To adjust the position of the mass 404 within the club shaft, the user can apply a downward force in directions 260, 380 (see FIGS. 11 and 16), overcoming the biasing force and engaging the screw head 104 with the well 224. The well 224 can include fingers or apertures that interlock with associated apertures or fingers provided on the screw head 104. The interlocking fingers / apertures prevent rotation of the screw head 104 and the associated screw 140 while allowing rotation of the second screw. Thus, by applying a downward force and a rotational force, the second screw rotates to axially adjust the position of the mass 404 within the club shaft. In other embodiments, the nested second screw can be incorporated into the adjustment members 208, 308 of the respective variable length shaft assemblies 200, 300.

[0130] In an embodiment of golf club 10 including adjustable mass 404 of adjustable mass assembly 400, golf club 10 can include one or more removable or adjustable weights provided within club head 14. The adjustable mass 404 and adjustable weights within club head 14 can together adjust characteristics of golf club 10, such as moment of inertia, total weight, and swing weight.

[0131] In another embodiment of golf club 10 including adjustable mass 404, mass 404 can be moved within club shaft 22 (and / or 120) to adjust swing weight while maintaining total weight. For example, by moving adjustable mass 404 closer to grip end 50, swing weight can be decreased while maintaining the same total weight. By moving adjustable mass 404 closer to club head 14, swing weight can be increased while maintaining the same total weight.

[0132] In one or more other examples of embodiments of golf club 10 including adjustable mass 404 of adjustable mass assembly 400, adjustable mass 404 can be moved within club shaft 22 (and / or 120) to adjust moment of inertia while maintaining total weight. Generally, by moving adjustable mass 404 closer to club head 14, moment of inertia can be increased while maintaining the same total weight. By moving adjustable mass 404 within club shaft 22 (and / or 120), moment of inertia can be adjusted or customized to a golfer's profile (e.g., swing style (upright, flat, etc.), strength, height, arm length, swing speed, swing tempo) to achieve a desired shot shape or dispersion pattern without substantially affecting total weight.

[0133] It should be recognized that the adjustable mass 404 can be used to adjust the mass distribution relative to the center of rotation of an individual golfer's golf swing. By adjusting the mass 404 closer to or farther away from the center of rotation of a given golf swing, club delivery to the golf ball can be improved. For example, adjusting the mass 404 can improve the attack angle, swing path, or consistency of the swing direction toward the golf ball. And this can result in a more consistent contact between the club head 14 and the golf ball.

[0134] In addition, it should be recognized that the adjustable mass 404 can be used to adjust the launch angle and / or ball flight of the golf ball after contact with the golf club 10. A golfer may desire to vary the launch angle or golf ball trajectory based on changes in swing mechanics, weather conditions, and / or course conditions. For example, the adjustable mass 404 can be moved to a first position within the club shaft to lower the launch angle or lower the golf ball trajectory in windy weather conditions to reduce the effect of the wind on the golf ball after contact. As another example, the adjustable mass 404 can be used to lower the launch angle or lower the golf ball trajectory in a links-style golf course or similar course conditions where the golfer benefits from a golf ball that rolls at the end of the ball flight. Similarly, the adjustable mass 404 can be moved to a second position within the club shaft to increase the launch angle or increase the golf ball trajectory.

[0135] In other embodiments, the mass 404 can be used to locally vary or increase the shaft stiffness along the shaft 22 (and / or shaft 120). Shaft stiffness is measured by an instrument that vibrates the shaft and measures the frequency in cycles per minute (CPM). A shaft that does not bend as easily is considered to have a stiff flex and a high frequency, while a shaft that bends easily is considered to have a softer flex and a lower frequency. By adjusting the position of the mass 404 within the shafts 22, 120 closer to the club head 14, the measured CPM is reduced, resulting in a softer or reduced shaft stiffness. Conversely, adjusting the position of the mass 404 within the shafts 22, 120 farther away from the club head 14 increases the measured CPM, resulting in a stiffer or increased shaft stiffness. Based on the optimal shaft performance in terms of the golfer's profile (e.g., swing style (upright, flat, etc.), strength, height, arm length, swing speed, swing tempo), as well as changes to swing mechanics, weather conditions, and / or course conditions, the golfer may desire to vary the shaft stiffness.

[0136] It should be appreciated that the adjustable mass 404 can be used in conjunction with one or more other adjustable aspects of the golf club 10 in addition to the variable length shafts disclosed herein. For example, the adjustable mass 404 can be used with adjustable club loft, adjustable club lie, adjustable face angle, and / or adjustable weights on the club head 14 at the address position (e.g., open, square, closed), improving customization for the golfer's profile (e.g., swing style (upright, flat, etc.), strength, height, arm length, swing speed, swing tempo).

[0137] FIG. 22 illustrates a method 600 of manufacturing a golf club 10 having variable length shaft assemblies 100, 200, 300, 500. The method 600 includes a step of preparing a first shaft 22 (step 602), a step of connecting the first shaft 22 to a club head 14 (step 604), a step of engaging a retainer 112 with the first shaft 22 (step 606), a step of connecting the variable length shaft assemblies 100, 200, 300, 500 to a second shaft 120 (step 608), and a step of connecting the first shaft 22 to the second shaft 120, where the retainer 112 engages the variable length shaft assemblies 100, 200, 300, 500 (step 610), and a step of attaching a grip 34 to the second shaft 120 (step 612).

[0138] FIG. 23 illustrates a method 700 of manufacturing a golf club 10 having an adjustable mass assembly 400. The method 700 includes a step of preparing a first shaft 22 (step 702), a step of connecting the first shaft 22 to a club head 14 (step 704), a step of connecting the adjustable mass assembly 400 to the first shaft 22 (step 706), and a step of attaching a grip 34 to the first shaft 22 (step 708).

[0139] The methods of manufacturing the golf club 10 described herein are merely exemplary and are not limited to the embodiments presented herein. The methods may be used in many different embodiments or examples not specifically shown or described herein. In some embodiments, the processes of the methods described may be performed in any suitable order. In other embodiments, one or more of the processes may be combined, separated, or skipped.

[0140] The variable-length shaft assemblies 100, 200, 300, 500 have certain advantages over the prior art. For example, the variable-length shaft assemblies 100, 200, 300, 500 cannot be seen from the outside of the golf club. The grip 34 is attached to and substantially overlaps the second shaft 120, while the first shaft 22 is received by the second shaft 120. Since the variable-length shaft assemblies 100, 200, 300, 500 and the second shaft 120 are not entirely visible from the outside of the golf club 10, the golf club 10 is more visually appealing and appears more like a traditional golf club 10. In addition, the variable-length shaft assemblies 100, 200, 300, 500 are lighter in weight, reducing the impact of the assembly on both the swing weight and the total weight of the golf club 10. Further, the variable-length shaft assemblies 100, 200, 300, 500 allow for adjustment of the club length while maintaining the orientation of the grip 34 (i.e., it does not change the rotational position of the grip 34). Also, the variable-length shaft assemblies 100, 200, 300 allow for adjustment of the club length with a single tool such as a torque wrench. Also, the single tool can be used to adjust other aspects of the golf club, such as the weight on the club head 14, the club loft, the club lie, the club face angle, etc., and / or to replace the shaft 22. In addition, the variable-length shaft assemblies 100, 200, 300, 500 allow the shaft length of the golf club 10 to be customized to the golfer's profile, such as the golfer's height, arm length, and / or natural address position.

[0141] The variable length shaft assembly 800 has advantages similar to those of the variable length shaft assemblies 100, 200, 300, and 500 described above, as well as further advantages over the prior art. For example, the variable length shaft assembly 800 reduces the lateral or radial movement between the first shaft 22 and the second shaft 120 by at least 70%. The bump-like protrusions of the insert 828 and the retainer 812 improve the concentricity of the first shaft 22 within the second shaft 120. Further, the interference operation between the threaded screw 140 and the rib 834 of the insert 828 provides a tight fit between the threaded screw 140 and the insert 828, thereby reducing the lateral or radial movement between the first shaft 22 and the second shaft 120. The alignment member 844 also provides additional means for improving the concentricity of the first shaft 22 within the second shaft 120, minimizing misalignment, and enabling the first shaft 22 to translate freely within the second shaft 120 during the operation of the variable length shaft assembly 800.

[0142] The adjustable mass assembly 400 has certain advantages over the prior art. For example, by adjusting the mass 404 within the club shaft 22 (and / or shaft 120), the swing weight of the club can be adjusted while maintaining the total weight, the moment of inertia can be adjusted while maintaining the total weight, and / or the shaft stiffness can be adjusted. In addition, after the contact has been adjusted, the golf ball trajectory can be adjusted, which may be desirable for different course conditions, weather conditions, or mechanical changes to the golfer's swing. Further, adjusting the mass 404 within the club shaft 22 (and / or shaft 120) adjusts the mass distribution of the golf club 10 relative to the center of rotation of the golfer's golf swing, improving the consistency of the attack angle, swing path, and / or swing direction towards the golf ball, resulting in a more consistent contact between the club head 14 and the golf ball.

[0143] The advantages are provided for purposes of example and it should be recognized that they are not comprehensive or limiting.

[0144] The replacement of one or more claimed elements constitutes a reconfiguration and does not constitute a repair. Additionally, benefits, other advantages, and solutions to problems have been described in connection with specific embodiments. However, any benefits, advantages, solutions to problems, and any one or more elements that may cause such benefits, advantages, or solutions to occur or become more prominent should not be construed as important, necessary, or essential features or elements of any or all of the claims unless such benefits, advantages, solutions, or elements are explicitly stated in such claims.

[0145] Since the rules of golf can change from time to time (e.g., new rules can be adopted or old rules can be eliminated or modified by golf standardization bodies and / or governing bodies such as the United States Golf Association (USGA), the Royal & Ancient Golf Club of St Andrews (R&A), etc.), the golf equipment related to the devices, methods, and articles of manufacture described herein may or may not comply with the rules of golf at any given time. Accordingly, the golf equipment related to the devices, methods, and articles of manufacture described herein can be advertised, presented for sale, and / or sold as compliant or non-compliant golf equipment. The devices, methods, and articles of manufacture described herein are not limited in this regard.

[0146] The above examples may be described in connection with a wood-type golf club, a fairway wood-type golf club, a hybrid-type golf club, an iron-type golf club, a wedge-type golf club, or a putter-type golf club. Alternatively, the apparatus, methods, and articles of manufacture described herein may be applicable to other types of sports equipment such as hockey sticks, tennis rackets, fishing poles, ski poles, and the like.

[0147] Moreover, the embodiments and limitations disclosed herein are not dedicated to the public under the doctrine of dedication where the embodiments and / or limitations (1) are not expressly claimed in the claims, (2) are equivalents or potential equivalents of elements and / or limitations in the claims under the doctrine of equivalents.

[0148] (Article 1) A golf club, comprising: a first shaft connected to a club head; a second shaft configured to slidably engage with a portion of the first shaft; a grip connected to the second shaft; and a variable-length shaft assembly at least partially positioned within the second shaft and configured to allow a portion of the first shaft to slide relative to the second shaft, wherein the variable-length shaft assembly includes an insert connected to an axial end face of the first shaft and having an aperture with a threaded portion, and an adjustment member having a screw with a threaded portion configured to meshingly engage with the threaded aperture of the insert, the adjustment member being configured to rotate and the insert being configured to move along the adjustment member when the adjustment member rotates, the adjustment member enabling the first shaft to slide relative to the second shaft to adjust the length of the golf club, and the grip being restricted from rotating around the first shaft or the second shaft when the first shaft slides relative to the second shaft.

[0149] (Clause 2) The golf club of Clause 1, wherein the variable-length shaft assembly includes a socket configured to receive a tool.

[0150] (Clause 3) The golf club of Clause 1, wherein an inner surface of the second shaft and an outer surface of the insert have a shape capable of restricting rotational movement between the second shaft and the insert.

[0151] (Clause 4) The golf club of Clause 3, wherein the inner surface of the second shaft and the outer surface of the insert have a hexagonal cross-sectional shape.

[0152] (Clause 5) The golf club of Clause 1, wherein the outer surface of the insert has a plurality of knob-like protrusions.

[0153] (Clause 6) The golf club of claim 1, wherein an inner surface of the insert comprises one or more ribs that engage an adjustment member.

[0154] (Claim 7) The golf club of claim 6, wherein a diameter of the screw with a threaded portion is larger than a diameter of an opening between one or more ribs.

[0155] (Claim 8) The golf club of claim 1, wherein the adjustment member is received by a retainer, the retainer being stationary relative to the second shaft and configured to allow rotation of the adjustment member.

[0156] (Claim 9) The golf club of claim 8, wherein the retainer comprises one or more pegs, the pegs being configured to be received by one or more apertures disposed on the second shaft.

[0157] (Claim 10) The golf club of claim 1, wherein the first shaft is received by an alignment member, the alignment member being positioned near a first end of the second shaft and configured to improve concentricity of the first shaft within the second shaft.

[0158] (Claim 11) A golf club, comprising a first shaft connected to a club head, a second shaft configured to slidably engage with a portion of the first shaft, a grip connected to the second shaft, and a variable-length shaft assembly at least partially positioned within the second shaft and configured to allow a portion of the first shaft to slide relative to the second shaft. The variable-length shaft assembly includes an insert connected to an axial end face of the first shaft and having an aperture with a threaded portion, and an adjustment member having a screw with a threaded portion configured to mesh with the threaded aperture of the insert. The adjustment member is configured to rotate, and the insert is configured to move along the adjustment member when the adjustment member rotates, thereby allowing the first shaft to slide relative to the second shaft and adjust the length of the golf club. The golf club further includes a retainer connected to the butting end of the second shaft and configured to receive the adjustment member, the retainer being stationary relative to the second shaft and configured to allow rotation of the adjustment member. The insert is positioned away from the retainer in the extended configuration and abuts against the retainer in the fully retracted configuration. The grip is restricted from rotating around the first shaft or the second shaft when the first shaft slides relative to the second shaft.

[0159] (Article 12) The golf club of claim 11, wherein the variable-length shaft assembly includes a socket configured to receive a tool.

[0160] (Article 13) The golf club of claim 11, wherein the inner surface of the second shaft and the outer surface of the insert have a shape configured to restrict rotational movement between the second shaft and the insert.

[0161] (Article 14) The golf club of clause 13, wherein the inner surface of the second shaft and the outer surface of the insert have a hexagonal cross-sectional shape.

[0162] (Clause 15) The golf club of clause 11, wherein the outer surface of the insert has a plurality of knob-shaped protrusions.

[0163] (Clause 16) The golf club of clause 11, wherein the outer surface of the retainer has a plurality of knob-shaped protrusions.

[0164] (Clause 17) The golf club of clause 11, wherein the inner surface of the insert has one or more ribs that engage with an adjustment member.

[0165] (Clause 18) The golf club of clause 17, wherein the diameter of the adjustment member is larger than the diameter of the opening between one or more ribs.

[0166] (Clause 19) The golf club of clause 11, wherein the first shaft is received by an alignment member that is positioned near the first end of the second shaft and is configured to improve the concentricity of the first shaft within the second shaft.

[0167] (Clause 20) The golf club head of clause 19, wherein the alignment member has one or more pegs that are configured to be received by one or more apertures disposed on the second shaft.

[0168] (Clause 21) The golf club of clause 11, wherein the insert engages a portion of the first shaft to define an engagement length, and the engagement length is 5.0 inches.

[0169] (Clause 22) The golf club of clause 11, wherein the outer surface of the retainer has a plurality of knob-shaped protrusions.

[0170] (Clause 23) The outer surface of the retainer has a hexagonal cross-sectional shape, the golf club of Clause 11.

[0171] (Clause 24) The second shaft is formed from nylon 66 having 30% carbon fiber filler material, the golf club of Clause 11.

[0172] (Clause 25) The insert and the first shaft move together when the adjustment member rotates, the golf club of Clause 11.

[0173] (Clause 26) The knob-shaped protrusion of the insert abuts against the inner surface of the second shaft, the golf club of Clause 15.

[0174] (Clause 27) The knob-shaped protrusion of the retainer abuts against the inner surface of the second shaft, the golf club of Clause 22.

[0175] (Clause 28) The screw with a threaded portion includes a diameter, one or more ribs define an opening diameter, and the diameter of the screw with a threaded portion is larger than the opening diameter between one or more ribs, the golf club of Clause 17.

[0176] (Clause 29) The diameter of the screw with a threaded portion is 0.25 inches, and the opening diameter between one or more ribs is 0.242 inches, the golf club of Clause 28.

[0177] (Clause 30) The insert is permanently connected to the axial end face of the first shaft, the golf club of Clause 11.

[0178] (Clause 31) The insert is connected to the axial end face of the first shaft by an adhesive, the golf club of Clause 30.

[0179] The various features and advantages of the present disclosure are set forth in the following claims.

Claims

1. A golf club, comprising: a first shaft connected to a club head; a second shaft configured to slidably engage with a portion of the first shaft; a grip connected to the second shaft; a variable-length shaft assembly at least partially positioned within the second shaft and configured to allow a portion of the first shaft to slide relative to the second shaft; wherein the variable-length shaft assembly comprises: an insert connected to an axial end face of the first shaft, the insert comprising an aperture with a threaded portion and a tubular portion without a threaded portion; a screw with a threaded portion configured to mesh and engage with the aperture with the threaded portion of the insert and configured to rotate, wherein in response to rotation of the screw with the threaded portion, the insert moves along the screw with the threaded portion, supports the first shaft, and allows the first shaft to slide relative to the second shaft to adjust the length of the golf club; the screw with the threaded portion is received by a retainer; the retainer is configured to remain stationary relative to the second shaft and allow rotation of the screw with the threaded portion; the insert is positioned away from the retainer in a configuration where the golf club is extended and abuts against the retainer in a configuration where the golf club is fully retracted; at least one of an outer surface of the insert and an outer surface of the retainer comprises a plurality of bump-like protrusions; the grip is a golf club whose rotation around the first shaft or the second shaft is restricted when the first shaft slides relative to the second shaft.

2. The golf club according to claim 1, wherein the variable-length shaft assembly includes a socket configured to receive a tool.

3. The golf club according to claim 1 or 2, wherein an inner surface of the second shaft and the outer surface of the insert have a shape capable of restricting rotational movement between the second shaft and the insert.

4. The golf club according to claim 3, wherein the inner surface of the second shaft and the outer surface of the insert have a hexagonal cross-sectional shape.

5. The golf club according to any one of claims 1 to 4, wherein the retainer includes one or more pegs configured to be received by one or more apertures disposed on the second shaft.

6. The golf club according to any one of claims 1 to 5, wherein the inner surface of the tubular portion includes one or more ribs that engage the screw with the threaded portion.

7. The first shaft is received by an alignment member, The golf club according to any one of claims 1 to 6, wherein the alignment member is positioned near an end of the second shaft and is configured to improve the concentricity of the first shaft within the second shaft.

8. The golf club according to claim 7, wherein the alignment member includes one or more pegs configured to be received by one or more apertures disposed on the second shaft.

9. The golf club according to claim 8, wherein the alignment member does not translate within the second shaft during operation of the variable-length shaft assembly.

10. A golf club, A first shaft connected to the club head, A second shaft configured to slidably engage a portion of the first shaft, A grip connected to the second shaft, A variable-length shaft assembly at least partially positioned within the second shaft and configured to allow a portion of the first shaft to slide relative to the second shaft, The variable-length shaft assembly includes An insert connected to the axial end face of the first shaft, the insert having a threaded aperture and a tubular portion without a threaded portion. A screw with a threaded portion that is configured to mesh and engage with the apertured portion with the threaded portion of the insert, and is configured to rotate, and in response to the rotation of the screw with the threaded portion, the insert and the first shaft are fixed to each other and move along the screw with the threaded portion to enable the first shaft to slide relative to the second shaft to adjust the length of the golf club, the screw with the threaded portion, An alignment member positioned near an end of the second shaft and configured to improve the concentricity of the first shaft within the second shaft, The screw with the threaded portion is received by a retainer, The retainer is configured to remain stationary relative to the second shaft and allow rotation of the screw with the threaded portion, The insert is positioned away from the retainer in a configuration where the golf club is extended, and the insert abuts against the retainer in a configuration where the golf club is fully retracted, At least one of the outer surface of the insert and the outer surface of the retainer includes a plurality of knob-like protrusions, The grip is a golf club whose rotation around the first shaft or the second shaft is restricted when the first shaft slides relative to the second shaft.

11. The golf club according to claim 10, wherein the variable-length shaft assembly includes a socket configured to receive a tool.

12. The golf club according to claim 10 or 11, wherein the insert and the first shaft are fixed to each other and move along the second shaft in response to rotation of the screw with the threaded portion.

13. The golf club according to any one of claims 10 to 12, wherein the inner surface of the second shaft and the outer surface of the insert have a shape capable of restricting rotational movement between the second shaft and the insert.

14. The golf club according to claim 13, wherein the inner surface of the second shaft and the outer surface of the insert have a hexagonal cross-sectional shape.

15. The golf club according to any one of claims 10 to 14, wherein the retainer comprises one or more pegs configured to be received by one or more apertures disposed on the second shaft.

16. The golf club according to any one of claims 10 to 15, wherein an inner surface of the tubular portion comprises one or more ribs that engage the screw with the threaded portion.

17. The golf club according to any one of claims 10 to 16, wherein the alignment member comprises one or more pegs configured to be received by one or more apertures disposed on the second shaft.

18. The golf club according to any one of claims 10 to 17, wherein the alignment member does not translate within the second shaft during operation of the variable length shaft assembly.

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