Retractable roller for a ladder

Abstract

Ladders, ladder feet, and roller assemblies can include a roller attached to a foot and extendable below a bottom surface of the foot, allowing the ladder or foot to roll on the ground. The roller can retract in response to a downward force applied to the foot, allowing the bottom surface to contact the ground and support the ladder or foot. The roller can be biased back to an extended position when the downward force is removed. A lock member, such as a rotatable arm, can be used to lock the roller in a retracted state.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 611,043, filed December 15, 2023, entitled “RETRACTABLE ROLLER FOR LADDERS,” the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure generally relates to rollers for ladders, and more particularly to retractable rollers for assisting in moving a ladder. Background Technology

[0004] Ladders are essential tools for workers to reach hard-to-reach areas, but moving them from one place to another is difficult and cumbersome. The length and weight of ladders make carrying them tiring, especially when they need to be moved multiple times a day. Some ladders include wheels to help users roll the ladder instead of carrying it, but wheels often still require users to reconfigure the ladder, such as unfolding and retracting the wheels each time they are used, or tilting and turning the ladder at unusual angles for the wheels to support it. Therefore, even ladders with wheels are cumbersome to move. For these and other reasons, there is a continuous need for improvements in the transportation of ladders and other tall objects. Summary of the Invention

[0005] One aspect of this disclosure relates to a ladder comprising: a pair of rails spaced apart from each other; a set of rungs coupled to and extending between the pair of rails; a roller assembly; and a locking member. The roller assembly includes a bracket slidable relative to one of the rails; and a roller rotatably coupled to the bracket and movable with the bracket relative to the rail. The roller assembly is movable relative to the rail between the first and second positions. In the first position, the roller extends below the bottom end of the rail. In the second position, the roller retracts relative to the first position. The roller assembly is movable from the first position to the second position in response to a downward force applied to one of the rungs. The locking member is movable between an unlocked position and a locked position. In the unlocked position, the bracket is movable between the first and second positions. In the locked position, the bracket is prevented from moving to the first position.

[0006] In some examples, the roller assembly further includes at least one biasing member that applies a force to bias the bracket from the first position toward the second position.

[0007] In some examples, the roller includes a wheel having an axle connected to the bracket.

[0008] In some examples, the roller includes a ball.

[0009] In some examples, the leg body is attached to the bottom end of the side rod, wherein the bracket is slidably attached to the leg body.

[0010] In some examples, the leg body includes a cavity in which the bracket can slide.

[0011] In some examples, the inner wall of the support body surrounds the bracket.

[0012] In some examples, the locking member includes a rotatable arm, wherein the bracket moves from a first position to a second position in response to rotation of the rotatable arm. The rotatable arm may include a cam and a pivot pin extending from the cam, wherein the pivot pin moves the bracket from the first position to the second position in response to rotation of the cam.

[0013] Another aspect of this disclosure relates to a support leg for a ladder, wherein the support leg includes: a body attachable to the bottom end of a side bar of the ladder, the body having a bottom surface; a roller rotatable relative to the body and movable relative to the body between an extended position and a retracted position; wherein when the roller is in the extended position, the roller extends below the bottom surface of the body; wherein when the roller is in the retracted position, the roller is located at or above the bottom surface of the body; and a spring configured to apply a force to the roller, the force pushing the roller from the retracted position toward the extended position.

[0014] In some embodiments, the support leg further includes a locking arm operable to lock the roller relative to the body in or above the retracted position.

[0015] In some examples, the body includes a laterally inward side, wherein the roller is located on the inner side of the body.

[0016] In some examples, the body includes an upper body and a lower body, wherein the bottom surface is located on the lower body, and wherein the lower body comprises a first material that is more elastic and flexible than the second material of the upper body.

[0017] In some examples, the body is configured to attach to the bottom end of the side bar at a non-orthogonal angle relative to the bottom surface. In some examples, the body includes a fore-toe portion, wherein when the roller is in the extended position, the roller is positioned above a plane, wherein the plane is orthogonal to the non-orthogonal angle and intersects the fore-toe portion.

[0018] In some embodiments, the roller includes a roller member and a carrier member, the roller member being rotatable relative to the carrier member, the carrier member being slidably coupled to the body.

[0019] Another aspect of this disclosure relates to a ladder assembly comprising: a first assembly including: a first pair of side bars spaced apart from each other; a first set of horizontal members extending between and connected to the first pair of side bars; a second assembly including: a second pair of side bars spaced apart from each other, the second pair of side bars being rotatably connected to the first pair of side bars; a second set of horizontal members extending between and connected to the second pair of side bars; and a pair of roller assemblies located at respective bottom ends of the first pair of side bars, each roller assembly including: a wheel; a biasing member; and a locking member, wherein the wheel is biased away from the respective bottom end to an extended position by the biasing member; wherein, in response to a downward force applied to the first assembly or the second assembly, the wheel is retractable to or above the bottom end to a retracted position; and wherein the locking member is configured to lock and unlock the wheel in the retracted position.

[0020] In some embodiments, the locking member is rotatable between a first position that locks the wheel in the retracted position and a second position that allows the wheel to move to the extended position.

[0021] In some examples, the pair of roller assemblies includes at least one housing, wherein the wheels are laterally covered by the at least one housing when the wheels are in the retracted position.

[0022] In some examples, the wheel translates relative to the bottom surface in response to rotation of the locking member.

[0023] The above summary of the invention is not intended to describe every embodiment or every implementation of the invention. The following drawings and detailed description illustrate one or more preferred embodiments in more detail. Attached Figure Description

[0024] The accompanying drawings illustrate various exemplary embodiments and are part of the specification. Together with this specification, these drawings demonstrate and explain various principles of this disclosure. A further understanding of the nature and advantages of the invention can be achieved by referring to the following drawings. In the drawings, similar parts or features may have the same reference numerals.

[0025] Figure 1 This is a perspective view of the ladder including the roller assembly.

[0026] Figure 2 yes Figure 1 A perspective view of the roller assembly.

[0027] Figure 3 yes Figure 2 A perspective view of the bottom of the roller assembly.

[0028] Figure 4 yes Figure 2 Exploded view of the roller assembly.

[0029] Figure 5A It is along Figure 3 The section indicator AA in the text represents the section at the extended position. Figure 2 A cross-sectional view of the roller assembly.

[0030] Figure 5B It is along Figure 3 The section indicator BB in the image captures the section at the extended position. Figure 2 A cross-sectional view of the roller assembly.

[0031] Figure 6A It is along Figure 3 The section indicator AA in the image captures the section in the middle position. Figure 2 A cross-sectional view of the roller assembly.

[0032] Figure 6B It is along Figure 3 The section indicator BB in the image captures the section in the middle position. Figure 2 A cross-sectional view of the roller assembly.

[0033] Figure 7A It is along Figure 3 The section indicator AA in the image captures the section in the locked, retracted position. Figure 2 A cross-sectional view of the roller assembly.

[0034] Figure 7B It is along Figure 3 The section indicator BB in the image captures the section in the locked, retracted position. Figure 2 A cross-sectional view of the roller assembly.

[0035] Figure 8This is a perspective view of one implementation of the roller assembly.

[0036] Figure 9 yes Figure 8 Exploded view of the roller assembly.

[0037] Figure 10 It is in an extended position. Figure 8 Side view of the roller assembly.

[0038] Figure 11 It is in the middle position. Figure 8 Side view of the roller assembly.

[0039] Figure 12 It is in the locked, retracted position. Figure 8 Side view of the roller assembly.

[0040] Figure 13 This is a side view of the side bar of the ladder, including the roller assembly.

[0041] Figure 14 This is a perspective view of one implementation of the roller assembly.

[0042] Figure 15 yes Figure 14 Exploded view of the roller assembly.

[0043] Figure 16 It is along Figure 14 The section indicator CC in the image captures a partial cross-sectional view of the roller assembly in its extended position.

[0044] Figure 17 It is along Figure 14 The section indicator CC in the image captures a partial cross-sectional view of the roller assembly located in the middle position.

[0045] Figure 18 It is along Figure 14 The section indicator CC in the image captures a partial cross-sectional view of the roller assembly in the locked, retracted position.

[0046] Figure 19 This is a perspective view of one implementation of the roller assembly.

[0047] Figure 20 yes Figure 19 Exploded view of the roller assembly.

[0048] Figure 21 It is in an extended position. Figure 19 Bottom perspective view of the roller assembly.

[0049] Figure 22 It is in the locked, retracted position. Figure 19Bottom perspective view of the roller assembly.

[0050] Figure 23 This is a perspective view of one implementation of the roller assembly.

[0051] Figure 24 yes Figure 23 Exploded view of the roller assembly.

[0052] Figure 25 It is in an extended state. Figure 23 A cross-sectional view of the roller assembly.

[0053] Figure 26 It is in a retracted state. Figure 23 A cross-sectional view of the roller assembly.

[0054] While the embodiments described herein are susceptible to various modifications and alternatives, specific embodiments have been illustrated by way of example in the accompanying drawings and will be described in detail herein. However, the exemplary embodiments described herein are not intended to be limited to the particular forms disclosed. Rather, this disclosure covers all modifications, equivalents, and alternatives falling within the scope of the appended claims. Detailed Implementation

[0055] The ladder disclosed herein may include a roller assembly configured to facilitate and accelerate movement of the ladder from one location to another. The rollers (e.g., wheels) at the feet of at least one set of side bars of the ladder may be spring-loaded, allowing a user to roll the ladder via the rollers when the ladder is in a substantially normal upright position, and the rollers may automatically retract upwards when the user applies their own weight (or other weight) to the first rung (or higher), thereby allowing the non-rolling portions of the ladder's feet to support the side bars with the rollers retracted. Furthermore, the roller assembly may include a locking mechanism that operates to lock the rollers in the retracted position when rolling is not required. The rollers may be mounted at the four feet of an upright, freestanding ladder, providing the user with a highly mobile ladder that can roll when extended (i.e., when the side bar assembly is extended). In various exemplary embodiments, the ladder may include rollers combined with legs, rollers separately connected to side bars (or connected to side bars in the absence of legs), wheel-shaped or spherical rollers, rollers connected to side bars or legs via brackets, and locking mechanisms operated via cams or levers.

[0056] This specification provides examples and does not limit the scope, applicability, or construction set forth in the claims. Therefore, it will be understood that changes may be made to the function and arrangement of the elements discussed without departing from the spirit and scope of this disclosure, and various embodiments may appropriately omit, substitute, or add other processes or components. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Moreover, features described with respect to certain embodiments may be combined in other embodiments.

[0057] Figure 1 This is a perspective view of a ladder 100 with retractable roller assemblies 102 and 112, which in some embodiments may be referred to as legs, roller legs, or leg assemblies. Ladder 100 may be referred to as a ladder assembly and represents various types of lifting platforms, such as benches, scaffolding, supports, and similar devices, all of which can be used in place of ladder 100. Ladder 100 may include a first assembly 104 comprising a pair of first pairs of side bars 106a and 106b (collectively referred to as side bars 106) spaced apart from each other. The first assembly 104 may include a first set of horizontal members, support bars, rungs, or crossbars 108 extending between and connected to the first pairs of side bars 106a and 106b.

[0058] In at least one example, ladder 100 may include a second component 114, which includes a second pair of side bars 116a and 116b (collectively referred to as side bars 116) spaced apart from each other. The second component 114 may include a second set of horizontal members, such as horizontal support bars, steps, or rungs 118, extending between and connected to the second pair of side bars 116a and 116b.

[0059] The second pair of side bars 116a and 116b can be rotatably connected to the first pair of side bars 106a and 106b. The second pair of side bars 116a and 116b can rotate about a rotation axis coinciding with a hinge, such as one formed in or formed by the top cover 110 or top rung of the ladder 100. In some embodiments, the ladder 100 may not include a top cover 110, and at least one hinge can directly pivotally connect the pairs of side bars (e.g., 106a, 116a or 106b, 116b), such as in articulated ladders or combination ladders that can be configured as freestanding, telescopic / upright, and folding types. Therefore, Figure 1 The ladder 100 is merely an exemplary application illustrating the principles and features disclosed herein, and the roller assemblies 102, 112 can be applied to various types of ladders.

[0060] A pair of lockable struts 120 can secure the ladder 100 in an open position for user use, for example, by fixing the second pair of side struts 116a and 116b at a fixed angle relative to the first pair of side struts 106a and 106b. The pair of lockable struts 120 can be folded, such as when the ladder 100 is folded up for storage. Therefore, the ladder 100 can have, for example... Figure 1 The ladder 100 is shown in a freestanding configuration, where its four legs 102, 112 support it on a generally horizontal surface. The ladder 100 can also be folded into a stowed position, in which the side bars 106, 116 are substantially parallel to each other, the lockable strut 120 pivots in the stowed position, and the legs 102, 112 are close to each other relative to the freestanding configuration. As further described below, the ladder 100 can also be moved to an inclined position, where two legs (e.g., 102a, 102b or 112a, 112b) support the ladder 100 regardless of whether the side bars 106, 116 are extended or folded. The ladder 100 may also optionally include one or more bottom support bars 122 to provide rigidity and support between the rungs 108, 118 (e.g., the bottom rung) and the side bars 106, 116.

[0061] The ladder 100 may include a first pair of roller assemblies 102a and 102b located at the respective bottom ends of the first pair of side bars 106a and 106b. The ladder 100 may include a second pair of roller assemblies 112a and 112b located at the respective bottom ends of the second pair of side bars 116a and 116b. As will be described in further detail below, the roller assemblies 102a, 102b, 112a, and 112b may be configured to: (i) in a first position, deploy a set of wheels or other rollers to allow a user to easily move or reposition the ladder 100 by rolling the ladder 100; and (ii) in a second position, retract the set of wheels or other rollers to provide stability when a user climbs the ladder. The rollers may be locked in the second position or unlocked in the second position. In the unlocked state, the rollers may automatically extend from the legs when a downward force (e.g., the user's weight) is removed from the ladder 100 for immediate repositioning. When locked, the wheels remain in the retracted position to prevent any rolling, even if the ladder is not under any weight.

[0062] Figures 2 to 3 This is a perspective view of the representative roller assembly 102 of the ladder 100. Figure 4This is an exploded view of roller assembly 102. As explained below, the rollers of roller assemblies 102 / 112 can be located laterally inside side bars 106 / 116. Therefore, roller assembly 102 can be used with side bars 106b and 116a, and a mirror / horizontally reversed version of roller assembly 102 can be used as either the roller assembly of side bars 106a and 116b. To avoid unnecessary repetition, roller assemblies 102, 112 will be... Figure 2 The roller assembly in the text is used as a representative reference.

[0063] As used herein, "longitudinal" or "longitudinally" facing refers to a direction parallel to the long longitudinal axis of the side bars 106, 116 to which the roller assembly 102 / 112 is directly attached (e.g., Figure 13 The longitudinal axis 801 (i.e., the longitudinal axis of the side rod 806) is used. The downward longitudinal direction refers to a direction parallel to the longitudinal direction and generally oriented downwards (e.g., away from the top cover 110 and towards the ground), and the upward longitudinal direction refers to a direction parallel to the longitudinal direction and generally oriented upwards (i.e., towards the top cover 110 and away from the ground). Furthermore, as used herein, the "lateral" direction is substantially horizontal when the ladder is in an upright (e.g., freestanding) position. The left-side direction extends to the user's left side when the user stands in front of the ladder preparing to step onto the first rung 108, while the right-side direction extends to the user's right side in this position, opposite to the left-side direction. The front lateral direction faces the user from the ladder in this position, and the rear lateral direction faces away from the user, located on the opposite side (relative to the ladder).

[0064] The roller assembly 102 may be attached to the bottom end of a side bar (e.g., 106, 116) of the ladder 100. The roller assembly 102 may include a body or housing 124 (also referred to as a leg body) that can be attached to the bottom end of a side bar 106 of the ladder 100. The housing 124 may include a laterally outer housing portion 124a (e.g., a side bar connecting portion, a side bar attachment portion, or a side bar receiver) defining a side bar cavity 125 (e.g., a connecting portion or a side bar connection opening) on ​​the laterally outer side of the housing 124, and the cavity 125 may include an internal wall configured to surround and cover the end of a side bar (e.g., side bar 106) inserted into the cavity 125. In some cases, the housing 124 may completely surround the bottom end of the side bar; and in other cases, the housing 124 may surround the side bar without covering the bottom end, i.e., the bottom end may be exposed (or extend through and beyond) the bottom of the housing 124. Therefore, the side bar can be attached to the roller assembly 102 via fasteners (such as screws or rivets), adhesives (such as epoxy resin), co-molding, similar techniques, and combinations thereof, so that the roller assembly 102 remains attached to the rest of the ladder 100.

[0065] In some embodiments, the roller assembly 102 may be attached to the bottom end of another extension member, rather than to the end of the side bar 106, such as the lateral / diagonal stabilizing legs, extension legs, leveling legs, or similar elongated, generally vertical support structures of the ladder 100 or other lifting platform equipment. Therefore, the relationship between the bottom end of the side bar 106 and the roller assembly 102 can be applied to these other structures, but to avoid unnecessary repetition, it will not be described separately, and this will be understood by those skilled in the art and those who benefit from this disclosure.

[0066] The roller assembly 102 may further include a bracket 126 slidably coupled to the housing 124 within a laterally inward housing portion 124b (e.g., a bracket receiving portion, a wheel connection portion, or a roller guard) defining a bracket cavity 129, and the bracket 126 may be configured to slide relative to the side rod 106 within the housing portion 124b. See also Figures 3 to 4 In some embodiments, the laterally outer housing portion 124a and the laterally inner housing portion 124b may be separate housings connected to each other, wherein they do not share common integrated wall features, but may be separate components attached to each other (e.g., via fasteners, clips, adhesives, etc.).

[0067] The bracket 126 can slide within the bracket cavity 129. The laterally inward housing portion 124b can be located laterally inward of the side bar 106 (and laterally inward of the laterally outward housing portion 124a) to minimize the overall lateral width of the ladder 100, which is advantageous for transport, storage, and packaging purposes. The laterally inward housing portion 124b can also be located laterally inward to help avoid damage to the housing portion 124b, as the laterally outward side of the ladder 100 is generally more susceptible to impact and breakage, including when handling and moving the ladder 100 in its independent and folded states. However, in various embodiments, the housing portion 124b can be located laterally outward of the side bar 106, or laterally forward or backward. The rollers can be referred to as being located inside the body, meaning that the rollers are configured on the side where the laterally inward half of the housing 124 is located.

[0068] In some embodiments, the roller assembly 102 may omit the side rod receiving cavity 125 and the walls surrounding the front, rear, and / or laterally outward cavities of the side rod 106. Therefore, in this case, the housing 124 may consist only of the laterally inward housing portion 124b with the bracket cavity 129 (without receiving the side rod 106 in the laterally outward housing portion 124a). The housing 124 (e.g., housing portion 124b) may be attached to the side surface of the side rod 106 (or other bottom structures of conventional ladder legs or vertical supports) without enclosing the side rod 106 within the cavity or side rod receiving housing portion (e.g., 125, 124a). This configuration allows for easy modification of the ladder to include the rollers of this disclosure without requiring a custom roller assembly to adapt and receive the bottom ends of existing legs or side rods.

[0069] The roller assembly 102 may include a roller 128 rotatably coupled to the bracket 126 and movable therewith within the cavity 129 relative to the side rod 106 and the housing portion 124b. (See reference...) Figures 5A to 7B The roller assembly 102 may be in a first position or an extended position (e.g., Figures 5A to 5B (as shown) and the second position or locked retraction position (as shown) Figures 7A to 7B The roller 128 moves between the side rod 106 (and the housing 124) and the bracket 126. In the first position, the roller 128 extends at least partially below the bottom end surface 127 of the side rod 106 (and the housing 124). In the second position, the roller 128 is retracted relative to the first position above the bottom end of the side rod 106. In other words, the roller 128 translates longitudinally upward relative to the bottom surface 127. In the retracted position, the wheel 140 can be laterally covered by the housing portion 124b. The roller 128 may include a wheel 140 having an axle 142 that connects the wheel 140 to the bracket 126 and defines the axis of rotation of the wheel 140.

[0070] In some embodiments, wheel 140 and axle 142 may be connected to a caster support connected to bracket 126. For example, in the extended position, wheel 140 and axle 142 may rotate about a vertical axis (or about the longitudinal axis of the side rail) in addition to rotating about a horizontal axis passing through axle 142. In this case, wheel 140 may be referred to as a caster and may enable the ladder to roll in multiple vertical lateral directions, such as rolling laterally to the left and right sides of the ladder, and rolling laterally to the front and rear sides of the ladder. As described herein, the caster may retract to (or above) the bottom surface 127 of housing 124, similar to wheel 140 as described herein. In various examples, the caster may be fully or partially received within bracket cavity 129.

[0071] The roller assembly 102 may include at least one biasing member 138 configured to apply a force that biases the bracket 126 from a second retracted position toward a first extended position. Figure 5B , 6B As shown in 7B, the biasing member 138 of component 102 may have an end configured to engage the generally longitudinally upward surface of the bracket 126 (within the top cavity (e.g., 126a) receiving the biasing member 138) and the generally longitudinally upward surface of the bracket cavity 129.

[0072] The biasing member 138 may include a spring (e.g., a coil spring, leaf spring, compression spring, similar devices, and combinations thereof) to push the bracket 126 longitudinally downward and toward the ground. The biasing member 138 may apply sufficient force such that when the ladder 100 is substantially unloaded (e.g., when a user is not standing on the ladder 100), the ladder 100 can be fully supported by and roll on the wheels 140 without contact between the bottom surface 127 of the side bar or foot / roller assembly 102 and the ground. However, the biasing member 138 may also apply appropriate force such that when the ladder is subjected to a downward load of a predetermined weight (e.g., the expected or average user's weight), the biasing force can be overcome, causing the wheels 140 to retract. Figures 6A to 6B The ladder 100 is positioned such that it is supported by the bottom surface 127 of the side bars or legs / rollers assembly 102.

[0073] The roller assembly 102 may include a locking member 130 movable between an unlocked position (e.g., a first rotational position) and a locked position (e.g., a second rotational position). The locking member 130 may include a rotatable arm 132 and a pivot pin 136 (e.g., a bolt, fastener, pivot arm, etc.). In some embodiments, the arm 132 and pivot pin 136 may be integrally formed. For example, the arm 132 and pivot pin 136 may be formed as a single integral component having a rod portion (similar to the pin 136 forming) that serves as a pivot pin and extends from the rotatable arm portion (similar to the rotatable arm 132 forming).

[0074] Pivot pin 136 can define a pivot axis, and rotatable arm 132 can rotate between multiple positions about said pivot axis, such as... Figures 5A to 7B As shown. Pivot pin 136 can extend through pin opening 135 of bracket 126 (see...) Figure 4 And therefore can move relative to the housing 124 with the bracket 126 and the wheels 140, such as Figure 5B , Figure 6B and Figure 7B As shown.

[0075] The rotatable arm 132 can rotate about the pivot pin 136 within an arm groove 133 on the inner side of the inner housing portion 124b. See also Figure 4 and Figure 5A The arm groove 133 may be defined between the inner housing portion 124b and the protective wall 137 positioned inwardly from the inner housing portion 124b. The protective wall 137 may protect the locking member 130 from impacts, scratches, and debris, and may help prevent objects from getting stuck in the groove 133. In some embodiments, the protective wall 137 may also engage with the rotatable arm 132, for example as... Figure 2 As shown, rotation of the rotatable arm 132 in the direction away from the front opening end of the slot 133 is prevented by contact between the lateral protrusion 139 of the rotatable arm 132 and the top surface of the protective wall 137.

[0076] The rotatable arm 132 may include a cam 134 (e.g., a cam portion, a right-angled portion, a triangular portion, or a housing contact portion). The cam 134 may have a generally triangular shape, such that the locking member 130 can be biased to locked and unlocked positions via an interconnection of the biasing member 138, the bracket 126, and the pivot pin 136. When the locking member 130 is in the unlocked position, the bracket 126 can move between a first position and a second position, and vice versa (e.g., in response to a force overcoming the biasing force applied by the biasing member 138). In the locked position, the bracket 126 is prevented from moving from the second position to the first position because the pivot pin 136 holds the bracket 126 in an elevated position within the inner housing portion 124b.

[0077] Figures 5A to 7B Cross-sectional views of the roller assembly 102 in various configurations are shown. Figures 5A to 5B These are the roller assembly 102 in a first position (e.g., a stationary position, an unlocked position, or an extended position) along... Figure 3 Cross-sectional view of roller assembly 102 of center line AA and BB. Figures 6A to 6B This is a similar cross-sectional view of the roller assembly 102, with the bracket 126 and locking member 130 in the intermediate unlocked retracted position, and Figures 7A to 7B This is a cross-sectional view of the roller assembly 102 in a second position (e.g., raised position, retracted position, or locked position), wherein the bracket 126 and the locking member 130 are held in place by the biasing member 138. Figures 5A to 7B The translation of wheel 140 relative to bottom surface 127 is shown in response to rotation of the locking member.

[0078] In the unlocked position, the locking member 130 allows the bracket 126 to move between a first position and a second position, for example, in response to a user stepping onto a rung of the ladder 100. Figure 5AThe wheel 140 extends below the bottom surface 127 of the side rod 106 (and below the bottom surface of the housing 124 and any lower body 123 located thereon). The biasing member 138 can apply a force to bias the bracket 126 to a first position where the potential energy of the cam 134 is at a local minimum due to contact between the first cam surface 134a of the cam 134 (e.g., the unlocked biasing surface portion or the first flat / flat side surface) and the flat / flat inner surface 133a of the slot 133. In other words, the biasing member 138 can (via the bracket 126) apply a force to the pivot pin 136 to hold the locking member 130 in place as the wheel 140 extends. Figure 5A The position. When no external downward force is applied to the crossbar 108 in a set of crossbars, the roller assembly 102 can be in the position. Figure 5A The position. In other words, when no user is standing on the ladder 100, the roller assembly 102 can be in a first position, in which the wheels 140 extend below the bottom surface 127 of the housing 124 (or lower body 123), thereby allowing the user to easily move the ladder 100 by relying on the wheels 140 to roll the ladder 100.

[0079] When a user applies sufficient downward force to the crossbar 108 to overcome the biasing force of the biasing member 138, such as when standing on the ladder 100, the roller assembly 102 can be pushed upward to... Figures 5A to 5B Move the first position to Figures 6A to 6B In the first position, the wheels 140 are retracted to (or above) the bottom surface 127 of the housing 124. In the second position, the bottom surface 127 of the housing 124 (or lower body 123) can contact the ground or other supporting surface below to provide stability and prevent the ladder 100 from rolling when the user applies weight to it.

[0080] The upward movement of wheel 140 also causes the bracket 126 and pivot pin 136 to move upward, which in turn causes the rotating arm 132 to move upward, as shown below. Figure 6A As shown. The upward movement of the rotating arm 132 moves the first cam surface 134a away from the flat / flat inner surface 133a. The center of gravity of the rotating arm 132 is located in front of the pivot pin 136. Figure 6A (on the right side), so arm 132 rotates about pivot pin 136 until the tip 134b of cam 134 contacts the inner surface 133a. Therefore, cam 134 can be positioned so that an angle or vertex contacts the inner surface 133a tangentially. When a downward force is removed from crossbar 108, cam 134 rotates back in response to the action of biasing member 138. Figure 5A The position. In other words, when the user steps on the crossbar 108, thus moving the wheel 140 to its position. Figure 6AWhen the cam 134 is in the desired position, the angular displacement of the cam 134 will not exceed the required threshold angular displacement (e.g., a rotation of 45 degrees or more around the pin 136), causing the rotating arm 132 to move to the position where the second cam surface 134c (e.g., the second flat side portion) of the cam 134 contacts the inner surface 133a (i.e., a rotation of approximately 90 degrees). Figure 7A (position) – This is what happens when the weight is removed. This allows the bracket 126 to automatically return to its roller extension position whenever the load on the ladder 100 is removed.

[0081] In some cases, even if the user is not standing on the ladder 100, the user can choose to keep the rollers 128 in the elevated position. In this case, the locking member 130 can be engaged from the ladder. Figure 5A Rotate the position to Figure 6A The position (e.g., in response to downward pressure on arm 132 via in) Figure 5A and Figure 6A (rotated clockwise around pivot pin 136 in the view), and then finally rotated to Figures 7A to 7B The locked position is shown. Rotation of the rotatable arm 132 causes the cam 134 to rotate, and in response to the rotation of the cam 134, the pivot pin 136 moves the bracket 126 upward. In other words, the wheel 140 is held at or above the bottom surface 127 of the housing 124.

[0082] In the locked position, the pivot pin 136 is raised sufficiently to hold the wheel 140 on a support surface below the ground or ladder 100, thus preventing the bracket 126 and roller 128 from moving back to the first position. The pivot pin 136 remains in a sufficiently elevated position due to the contact between the second cam surface 134c and the inner surface 133a of the housing. The distance between the pivot pin 136 and the second cam surface 134c (e.g., distance D) is greater than the distance between the pivot pin 136 and the first cam surface 134a; therefore, the wheel 140 remains raised when the arm 132 rotates to the locked position. Furthermore, the biasing member 138 pushes the pivot pin 136 downward (through the bracket 126), so that when the arm 132 is rotated upward and away from the locked position, the biasing force of the biasing member 138 must be overcome.

[0083] When an upward force is applied to the rotatable arm 132 to overcome the force of the biasing member 138 on the pin 136, the locking member 130 can move back to the unlocked position (e.g., Figure 5A This causes arm 132 to move back. Figure 6A The position, and then move back. Figure 5A The position. Because arm 132 (at 139) is in contact with protective wall 137, it is possible to prevent arm 132 from rotating beyond the unlocked position (e.g., moving counterclockwise beyond...). Figure 5A (Location).

[0084] The main body or housing 124 may include an upper body 121, on which a lower body 123 (e.g., a foot pad, engagement pad, or elastic block) is mounted. The lower body 123 may support a bottom surface 127. The lower body 123 may include a first material that is more elastic, flexible, or compressible than the second material of the upper body 121. The first material of the lower body 123 may be configured to absorb impact forces and provide grip along the ground to provide additional stability to the ladder 100 when the roller assembly 102 is in the second position and / or when a user climbs the ladder 100 and the ladder 100 is supported by contact between the ground and the lower body 123. In contrast, the second material of the upper body 121 may be rigid to provide support for the roller assembly 102 on the side bar 106.

[0085] Figures 8 to 12 Alternative implementation schemes involving roller assembly 802. Figure 8 This is a perspective view of roller assembly 802. Figure 9 For the exploded diagram, and Figures 10 to 12 The views are of the unlocked / extended state, the intermediate unlocked / retracted state, and the locked / retracted state, respectively. Unless otherwise stated, the configuration of the roller assembly 802 may be substantially similar to that of the roller assembly 102. For example, the roller assembly 802 may be attached to the bottom end of a side bar of a ladder (such as side bar 106 of ladder 100).

[0086] In contrast to the straight, angled shapes of the rotatable arm 132 and cam 134 of roller assembly 102, the locking member 830 of roller assembly 802 can have a generally circular cam 834. The locking member 830 can be mounted to a housing 824, which is very similar to housing 124 but lacks the protective wall 137. The locking member 830 may include a rotatable arm 832 and a cam 834. The rotatable arm 832 is rotatable about a pivot pin 136, which is offset relative to the center of the surface of the cam 834 of the locking member 830. Therefore, when the cam 834 is in... Figure 8 and Figure 10 When the housing 824 is in the upright, unlocked position, the first distance between the lower cam support surface 833a of the housing 824 and the pivot pin 136 at the circular contact surface 834a of the cam 834 is less than when the flat cam surface 834b of the cam 834 is in the open position. Figure 12 The second distance between the lower cam support surface 833a and the pivot pin 136 when the locking position contacts the lower cam support surface 833a. Therefore, when the locking member 830 rotates from the unlocked position to the locked position, the pivot pin 136 moves upward to retract the bracket 126 and the wheel 140, similar to the roller assembly 102. Figure 12 Surface 834b is shown in dashed lines because it is located behind arm 832.

[0087] The flat cam surface 834b can abut against the lower cam support surface 833a at a slightly smaller radial distance than the circular surface portion 834c of the cam 834 adjacent to the flat cam surface 834b. Therefore, the flat cam surface 834b can provide stability to the cam 834 when it is in the unlocked position, and requires the user to overcome a minimal force applied by the biasing member 138 to begin unlocking the locking member 830 (i.e., away from it). Figure 12 Rotate the position onto surface portion 834c and face it. Figure 11 (Position). The minimum force can help limit or prevent the bracket 126 from being accidentally unlocked.

[0088] When the roller assembly 802 is in Figure 10 When the ladder is in its retracted position, the weight applied to it can push the wheel 140 to the retracted position. To prevent the wheel 140 from accidentally locking due to the pivot pin 136 moving upwards while the circular contact surface 834a contacts the lower cam support surface 833a (e.g., to prevent it from moving to the retracted position), Figures 11 to 12 The position of the lock component 830 can be configured to the unlocked position. Figure 10 In the unlocked position, the center of gravity of the locking member 830 is located behind the pivot pin 136 (e.g., Figure 10 (Left side of the ladder). Therefore, when weight is applied to the ladder and pin 136 is pushed upward by bracket 126, arm 832 is biased towards the rear (i.e., towards the longitudinal surface 833b of housing 824) under the influence of gravity. Thus, circular contact surface 834a will rotate about pin 136 and contact longitudinal surface 833b, and cam 834 will no longer rotate. Releasing the weight on the ladder from this position will allow pivot point 136 and cam 834 to return to their original positions. Figure 10 The extended position of the unlock.

[0089] Figure 13 This is a side view of the side bar 806 and roller assembly 802 of ladder 800, indicating various example dimensions. Side bar 806 may be substantially similar to any of the side bars 106a, 106b, 116a, or 116b of ladder 100. Furthermore, except for roller assembly 802, ladder 800 may be substantially similar to ladder 100. Moreover, it will be apparent to those skilled in the art that, in combination with… Figure 13 The features of the roller assembly 802 described herein can be applied to any roller assembly or foot described herein, such as, for example, assembly 102, 1402, 1902, 2302, etc.

[0090] When the ladder 800 is in the standing position, the bottom surface 127 of the housing 824 can be configured to be positioned parallel to the ground or supporting surface to maximize the traction between the ladder 800 and the ground. The housing 824 can be configured to be attached to the bottom end of the side bar 806 at a non-orthogonal angle relative to the bottom surface 127 of the housing 824. For example, as... Figure 13 As shown, housing 824 can be attached to form an angle A1 of approximately 72 degrees between the horizontal ground and the longitudinal axis of side rod 806. In other examples, the angle may be greater than or less than 72 degrees.

[0091] The housing 124 may have a front toe 829 (e.g., an end, end point, end edge, or sloping support edge). When the wheel 140 is in the extended position, the wheel 140 lies below the plane of the bottom surface 127 and the toe 829. Furthermore, when the roller is in the extended position, the bottom surface 127 may be approximately 0.48 inches above the ground or the bottommost surface of the wheel 140. In other embodiments, the roller may extend to different distances. Thus, in this configuration, the ladder 800 can be supported by the rollers when no downward force is applied to any rung of the ladder 800.

[0092] The axis of rotation of wheel 140 can be located approximately midway between the front and rear surfaces of side rod 806. Therefore, in an exemplary embodiment, the distance between the center of wheel 140 and either (front or rear) surface of side rod 806 can be approximately 1.60 inches, and the total distance between the front and rear surfaces can be approximately 3.20 inches. Furthermore, the axle 142 of the roller can be substantially centrally located within housing 824.

[0093] Sometimes, a user may want to tilt the side bar of ladder 800 toward the user (e.g., rotate side bar 106 to allow top cover 110 to pass over first pair of legs 102), without the bottom of the ladder relying on rollers 128 to roll away from the user. The user can lock the rollers in the retracted position to prevent them from rolling. However, if the rollers extend, the front toe 829 of housing 824 can be configured to support ladder 100 without wheels 140 simultaneously contacting the ground. For example, ladder 800 can be entirely supported by the non-rolling toe 829. To achieve this behavior, the toe 829 can be offset forward relative to wheels 140 such that the plane 850 positioned at angle A2 (i.e., offset approximately 90 degrees relative to the rear surface of side bar 806 (and intersecting with the toe 829)) does not intersect with wheels 140. In other words, as Figure 13 As shown, wheel 140 can be offset longitudinally upward relative to plane 850. Plane 852, which intersects both the bottom and toe 829 of wheel 140, can be offset relative to plane 850 at approximately a four-degree angle (e.g., ...). Figure 13The offset angle (P) allows the ladder 800 to tilt and rotate slightly when supported by the toe 829 without the wheels 140 re-engaging with the ground.

[0094] Figures 14 to 18 Another alternative implementation of the roller assembly 1402 involving ladder 1400. Figure 14 This is a perspective view of roller assembly 1402. Figure 15 This is an exploded view of roller assembly 1402. Figures 16 to 18 These are partial cross-sectional views of the roller assembly 1402 in the extended position, the intermediate retracted / unlocked position, and the retracted / locked position (along...). Figure 14 (The section line 16-16 is used for cutting).

[0095] Except for the differences described below, ladder 1400 is substantially similar to ladder 100 and ladder 800. The roller assembly 1402 may include a housing 1424, a bracket 1426 for receiving the wheels 140 within the housing 1424, and a locking member 1430. The locking member 1430 may include a rotatable arm 1432 (e.g., a lever arm, pivot arm, or swing arm), one or more pivot pins 1436, and one or more stops 1444.

[0096] like Figures 16 to 18 As shown, the rotatable arm 1432 may also include one or more cam protrusions 1434 configured to extend into a bracket cavity (e.g., 1429, similar to cavity 129) in the housing 1424. The protrusions 1434 may engage one or more generally downward-facing surfaces 1433 on the bracket 1426. Therefore, the engagement between the protrusions 1434 and the downward-facing surfaces 1433 prevents the bracket 1426 from falling out of the bracket cavity 1429. The downward-facing surfaces 1433 may be defined at the apexes of two opposing recesses 1435 in the side of the bracket 1426.

[0097] When in Figure 16 In the indicated position, the rotatable arm 1432 may have a first bracket contact surface 1434a that contacts the downward-facing surface 1433 of the bracket 1426. Rollers extend below the bottom surface of the housing 1424, similar to... Figure 5A The position is such that the wheels 140 and bracket 1426 are in the unlocked state, meaning that the wheels 140 and bracket 1426 can be pushed longitudinally upward in response to the weight applied to the ladder rungs until the bracket 1426 reaches the desired position. Figure 17 The location. For example... Figure 17As shown, when the downward-facing surface 1433 moves upward, the rotatable arm 1432 can rotate downward on its inner side because its center of gravity is located laterally inward of its pivot axis. When the weight is released, the wheel 140 and the bracket 1426 can be biased back by the biasing member 138 in the bracket 1426. Figure 16 The position is such that, because the rotatable arm 1432 does not rotate sufficiently beyond the pointed transition end 1434b of the protrusion 1434, the downward-facing surface 1433 does not engage with the second bracket contact surface 1434c.

[0098] The user can switch the locking member 1430 to the locked state, thereby holding the bracket 1426 in the raised position, such as... Figure 18 As shown, at this time, wheel 140 retracts to the bottom surface (e.g., 127) or above the bottom surface. The procedure for locking mechanism 1430 may include moving the rotatable arm 1432 (from...) Figure 17 The position) pivots downwards on its inner side (e.g., the side with the inwardly extending portion / handle / user foot engagement portion). Figure 18 The second bracket contact surface 1434c engages the downward-facing surface 1433 of the bracket 1426, and the stop 1444 engages the housing 1424. The distance from the adjacent pivot pin 1436 of the arm 1432 to the second bracket contact surface 1434c can be greater than the distance from the same pivot pin to the first bracket contact surface 1434a. Therefore, the bracket 1426 can be positioned via the second bracket contact surface 1434c. Figure 18 The second bracket contact surface 1434c may be slightly rounded or concave to receive the convex-facing downward-facing surface 1433 of the bracket 1426, thereby providing stability for engagement. The first bracket contact surface 1434a may also be slightly concave to provide stability in the unlocked extended state of the bracket 1426. When the inside of the rotatable arm 1432 moves downward, the stop 1444 prevents the arm 1432 from rotating beyond the locked position.

[0099] The rotatable arm 1432 may include a generally U-shaped profile (viewed from above), with the ends of the profile formed by cam protrusions 1434. The center of the rotatable arm 1432 may serve as a handle or foot pedal to assist a user in rotating a joystick about a pivot pin 1436. The rotatable arm 1432 may include a rigid material, such as a metal (e.g., steel or aluminum), and may be formed via stamping, casting, and similar methods. The size and shape of the stop 1444 of the arm 1432 may be configured to distribute pressure onto the lateral inner wall 1424a of the housing 1424 (see [link to relevant documentation]). Figure 15 This is to prevent damage to wall 1424a when arm 1432 rotates excessively downward.

[0100] Figures 19 to 22Another exemplary embodiment of the roller assembly 1902 of the ladder 1900 is shown. Figure 19 This is a perspective view of roller assembly 1902. Figure 20 It is a decomposed diagram, and Figures 21 to 22 These are bottom perspective views of the roller assembly 1902 in its extended unlocked position and retracted locked position, respectively. The components and features of the roller assembly 1902 are similar to or identical to those of the other roller assemblies described above (particularly assembly 1402). Therefore, the roller assembly 1902, where applicable, incorporates the aforementioned features and functions, for example, including a housing 1424, a bracket 1426, a wheel 140, an offset member 138, etc., as... Figure 20 As shown.

[0101] Locking member 1930 may include a rotatable arm 1932 having a pair of cam protrusions 1934 that function in the same manner as cam protrusions 1434, such as Figure 21 and Figure 22 As shown. Figure 19 As shown, the rotatable arm 1932 may also include a paddle-shaped or enclosed panel shape, wherein the outer ridge portion 1940 surrounds the inner panel 1942. The lower end of the rotatable arm 1932 may include an abutment surface 1944 (see...). Figure 19 and Figure 21 The abutment surface is configured to be in the locked position when the rotatable arm 1932 is in the locking position (i.e. Figure 22 When the rotatable arm 1932 is in the locked position, it rotates together with the arm 1932 to abut, contact, and engage the lateral inner wall 1424a of the housing 1424. The abutment surface 1944 can be substantially flat and a plane parallel to the axis of rotation of the rotatable arm 1932. Therefore, when the rotatable arm 1932 is in the locked position, the planar surface of the rotatable arm 1932 (i.e., the abutment surface 1944) can contact the planar surface of the housing 1424 (i.e., the planar surface on the wall 1424a). The contact of the planar surfaces can distribute pressure over a larger area (e.g., most of the width of the rotatable arm 1932), thereby reducing the localized stress on the wall 1424a of the housing 1424 caused by the arm 1932, and thus reducing any risk of damage caused by contact with the arm 1932. Furthermore, compared to the shape of the thinner contact surface of the arm 1432 (on the stop 1444), the surface 1944 allows the rotatable arm 1932 to be made of a less rigid or durable material (such as, for example, plastic or composite material) because the pressure distribution of the arm 1932 is more uniform.

[0102] Figures 23 to 26Another exemplary embodiment of a roller assembly 2302 for a ladder is shown. The roller assembly 2302 can be attached to or integrated into the bottom end of various embodiments of the ladder (e.g., 100, 900) and side bars (e.g., 106, 116) described herein. The roller assembly 2302 may include a housing 2324 (including an upper housing 2321 and a lower housing 2323) having features common to other housings described herein (e.g., housing 124). The housing 2324 may include a lateral outer housing portion 2324a and a lateral inner housing portion 2324b, and the lateral inner housing portion 2324b may surround at least one biasing member 2328 and a bracket 2326 for retaining the roller 2328.

[0103] The bracket 2326 may include at least one (e.g., a pair) lateral latches 2340. The width of the latches 2340 may be defined as slightly larger than the width or diameter of the opening at the bottom of the lateral inner housing portion 2324b. Therefore, when the bracket 2326 is inserted into the bottom opening of the lateral inner housing portion 2324b, the top ramp surface of the latches 2340 pushes the latches 2340 radially inward (from opposite sides of the bracket 2326 toward each other) to allow the bracket 2326 to travel into the bottom opening. Figure 23 , Figure 25 and Figure 26 As shown, when a sufficient insertion depth is reached, the hook 2340 can be outwardly engaged into the corresponding retaining groove 2342 in the side of the lateral inner housing portion 2324b. The downward-facing surface of the hook 2340 can be parallel to the bottom surface of the groove 2342 and not sloped, so the hook 2340 can "hook" the bracket 2326 onto the housing 2424 to prevent the bracket 2326 from retracting or extending relative to the housing 2424 beyond its maximum extension displacement, such as... Figure 25 As shown. However, the length of the slot 2342 can extend below the top of the lateral inner housing portion 2324b to allow the bracket 2326 to move upward into the lateral inner housing portion 2324b before reaching the maximum inward displacement / retraction position relative to the maximum extension position, as shown. Figure 26 As shown.

[0104] Roller 2328 may be a generally spherical roller or ball configured to snap into the bottom end of bracket 2326. Once inserted, the bottom end of bracket 2326 can surround roller 2328 with a diameter slightly smaller than the maximum diameter of roller 2328, thereby preventing roller 2328 from falling out of bracket 2326 when not in contact with the ground. As with other embodiments disclosed herein, biasing member 2328 can bias bracket 2326 to an extended position ( Figure 25This allows the ladder to which the roller assembly 2302 is attached to to roll on the ground or other supporting surfaces by means of the rollers 2328. The spherical rollers 2328 can slide within the bracket 2326 and roll in any direction, thus giving the ladder additional degrees of freedom of movement compared to embodiments using wheels (e.g., 140). Therefore, the rollers 2328 can allow the ladder to roll laterally to the left or right relative to a user holding both side bars and facing forward at the roller assembly 2302. Similarly, the rollers 2328 can roll laterally forward or backward relative to a user in that position. Thus, the spherical rollers 2328 can provide additional mobility to a rolling ladder in a manner similar to pivoting casters, but in a compact and simplified form.

[0105] When sufficient weight is applied to the ladder (e.g., rungs) to overcome the biasing force of the biasing member 2328, the bracket 2326 can retract with the rollers 2328 to allow the lower portion of the lower housing 2323 / housing 2324 to support the ladder in place of the rollers 2328 (or in addition to the rollers). Therefore, when a user stands on a rung, the rollers 2328 can move to the retracted position, and the ladder cannot roll during this period.

[0106] The locking mechanism for holding the bracket 2326 in the retracted position even when no weight is applied to the ladder is not shown in conjunction with the roller assembly 2302. However, those skilled in the art, and who benefit from this disclosure, will understand that locking members (e.g., rotatable arm 132 and pivot pin 136) and a flat surface 133a can be added to the roller assembly 2302 to achieve retracted locking of the bracket 2326.

[0107] Various ladder embodiments can be manufactured using the features and principles disclosed herein for various roller assembly embodiments. A ladder can be constructed by using two roller assemblies 2302 on the rear side bar (e.g., 116) and two roller assemblies 102 on the front side bar (e.g., 106). In this way, due to the wheels of the roller assembly 102, one half of the ladder's legs can roll along a single axis of motion, while due to the rollers of the roller assembly 2302, the other half of the legs can roll in any lateral direction. Another embodiment may include wheels (e.g., 140) on all roller assemblies (e.g., as shown in ladder 100) for primary rolling mobility along a single axis of motion (e.g., forward and backward directions). Another embodiment may include ball rollers (e.g., 2328) on all four legs to allow horizontal rolling in any direction at all four legs.

[0108] This document describes various inventions with reference to certain specific embodiments and examples. However, those skilled in the art will recognize that many variations are possible without departing from the scope and spirit of the invention disclosed herein, as the inventions set forth in the following claims are intended to cover all variations and modifications of the disclosed invention without departing from its spirit. The terms "comprising" and "having" as used in the specification and claims shall have the same meaning as the term "including".

Claims

1. A ladder comprising: A pair of side bars, the pair of side bars being spaced apart from each other; A set of crossbars, the set of crossbars being connected to the pair of side bars and extending between the pair of side bars; Roller assembly, the roller assembly comprising: A bracket, the bracket being slidable relative to one of the pair of side bars; and A roller, which is rotatably connected to the bracket and is movable relative to the side rod with the bracket; The roller assembly is movable relative to the side rod between a first position and a second position; In the first position, the roller extends below the bottom end of the side rod; In the second position, the roller is retracted relative to the first position; The roller assembly is capable of moving from the first position to the second position in response to a downward force applied to one of the crossbars in the set of crossbars; and A locking member is movable between an unlocked position and a locked position, wherein in the unlocked position the bracket is movable between a first position and a second position, and wherein in the locked position the bracket is prevented from moving to the first position.

2. The ladder of claim 1, wherein the roller assembly further comprises at least one biasing member that applies a force biasing the bracket from the first position toward the second position.

3. The ladder of claim 1, wherein the rollers include wheels having an axle connected to the bracket.

4. The ladder according to claim 1, wherein the rollers comprise spheres.

5. The ladder according to claim 1, further comprising a leg body connected to the bottom end of the side bar, wherein the bracket is slidably connected to the leg body.

6. The ladder according to claim 5, wherein the leg body includes a cavity, and the bracket is slidable within the cavity.

7. The ladder according to claim 6, wherein the inner wall of the leg body surrounds the bracket.

8. The ladder of claim 1, wherein the locking member includes a rotatable arm, wherein the bracket moves from the first position to the second position in response to rotation of the rotatable arm.

9. The ladder of claim 8, wherein the rotatable arm includes a cam and a pivot pin extending from the cam, wherein in response to rotation of the cam, the pivot pin moves the bracket from the first position to the second position.

10. A support leg for a ladder, the support leg comprising: The main body is capable of being attached to the bottom end of the side bar of the ladder, and the main body has a bottom surface; A roller, which is rotatable relative to the body and movable relative to the body between an extended position and a retracted position; When the roller is in the extended position, the roller extends below the bottom surface of the main body; When the roller is in the retracted position, the roller is located at or above the bottom surface of the main body; A spring configured to apply a force to the roller, the force pushing the roller from the retracted position toward the extended position.

11. The leg of claim 10, further comprising a locking arm operable to lock the roller relative to the body at or above the retracted position.

12. The support leg of claim 10, wherein the body includes a laterally inward side, wherein the roller is located on the inner side of the body.

13. The leg of claim 10, wherein the body comprises an upper body and a lower body, wherein the bottom surface is located on the lower body, wherein the lower body comprises a first material that is more elastic and flexible than the second material of the upper body.

14. The support leg of claim 10, wherein the body is configured to be attached to the bottom end of the side rod at a non-orthogonal angle relative to the bottom surface.

15. The leg of claim 14, wherein the body includes a fore toe portion, wherein when the roller is in the extended position, the roller is located above a plane that is orthogonal to the non-orthogonal angle and intersects the fore toe portion.

16. The support leg of claim 10, wherein the roller comprises a roller member and a support member, the roller member being rotatable relative to the support member, the support member being slidably connected to the body.

17. A ladder assembly comprising: The first component includes: The first pair of side bars spaced apart from each other; The first set of horizontal members extends between and connects to the first opposite side members; The second component includes: A second pair of side rods spaced apart from each other, the second pair of side rods being rotatably connected to the first pair of side rods; The second set of horizontal members extends between and connects to the second pair of side bars; A pair of roller assemblies, the pair of roller assemblies being located at the respective bottom ends of the first pair of side rods, each of the pair of roller assemblies comprising: wheel; Offset components; and Locking component, The wheel is biased away from the corresponding bottom end to an extended position by the biasing member; In response to a downward force applied to the first component or the second component, the wheel can retract to the bottom end or above the bottom end to reach the retracted position; and The locking member is configured to lock and unlock the wheel in the retracted position.

18. The ladder assembly of claim 17, wherein the locking member is rotatable between a first position locking the wheel in the retracted position and a second position allowing the wheel to move to the extended position.

19. The ladder assembly of claim 17, wherein the pair of roller assemblies includes at least one housing, wherein when the wheels are in the retracted position, the wheels are laterally covered by the at least one housing.

20. The ladder assembly of claim 17, wherein the wheels translate relative to the bottom end in response to rotation of the locking member.

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