Field of Invention

[0001] The present invention generally relates to the field of commercial trucks and carts for carrying merchandise items such as various types of product containers. More specifically the present invention relates to pallet jacks with adjustable width fork blades.

Background

[0002] In general, adjustable pallet jacks are used for applications where there is a need for lifting and moving a variety of containers and pallets. Forks of adjustable pallet jacks can be moved closer or opened apart to accommodate larger or smaller containers or to accommodate containers having a narrow or wide weight distribution. A common adjustable pallet jack design includes securing each fork to a base with bolts. In such a design, to move a fork, bolts securing the fork to the base are removed, the fork is manually repositioned, and the bolts are re-inserted through the base at a different location. Movement of a fork can therefore be time consuming and strenuous. Further, forks can only be positioned at a few discrete locations as allowed by the positioning of through-holes for the bolts to pass through the base.

[0003] Another available adjustable pallet jack design includes a crank that is permanently affixed to the pallet jack base that can be turned to open and close the forks. While the crank is an improvement in terms of ease of use in comparison to designs requiring the removal of bolts to move forks, cranks are large and can be cumbersome for smaller pallet jack designs. Further, the crank handle can be in the way when positioned at certain angles of rotation, so while it’s possible to position forks over a continuum of positions, practical fork positions - corresponding to an out- of-the way crank angle - are finite.

[0004] There is therefore a need for an improved adjustable pallet jack design. Summary

[0005] According to the present invention, adjustable pallet jacks can generally include movable fork assemblies that can each independently be positioned from an open position to a close position and a continuum of in-between positions by turning a detachable crank. The crank can be stored within a housing of the adjustable pallet jack when not in use. Wheels under the fork assemblies can be raised and lowered as controlled by a handle assembly.

[0006] Each of the fork assemblies can include a threaded guide block that is insertable during assembly of the adjustable pallet jack through a slot in the housing of the adjustable pallet jack. A pair of threaded rods, one for each fork, can be affixed within the housing of the adjustable pallet jack and each can be rotated to move an associated threaded guide block along a threaded portion of the threaded rod - thereby moving the associated fork inwardly or outwardly between the open and close positions. The threaded rods can have an end shaped to mate with a removable crank that is accessible through a crank slot on the housing of the adjustable pallet jack. Rotation of the crank mated to a threaded rod can thereby move the associated fork assembly between the open and close positions.

[0007] The handle assembly can be attached to the housing and the fork assemblies with a control arm assembly that can allow the handle assembly to control the raising and lowering of the wheels under the fork assembly. The control arm assembly can include a pair of pivot forks each attached to a first end of a connecting rod within each fork assembly, and each connecting rod can be connected at a second end to a wheel assembly under a fork blade of the fork assembly. Pivoting of each pivot fork therefore can move the associated connecting rod causing the associated wheel to raise or lower. Each pivot fork can be slidably attached to a pivot bar of the control arm assembly such that when a fork blade of the adjustable pallet jack is moved from an open to a close position, the associated pivot fork slides laterally along the pivot bar. An axel can be positioned within the pivot bar to affix the pivot bar to the housing assembly of the adjustable pallet jack. The pivot bar can be mounted on a support structure including a pivot arm, an arm support, and a center support. The support structure of the control arm assembly can include bore holes and can be attached to the handle assembly with pins.

Brief Description of the Drawings

[0008] The above and further aspects of this invention are further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the invention. The figures depict one or more implementations of the inventive devices, by way of example only, not by way of limitation.

[0009] FIGs. 1A and IB illustrate open and close positions of forks of an exemplary adjustable pallet jack according to aspects of the present invention;

[0010] FIG. 2 illustrates a rear perspective view of an exemplary adjustable pallet jack according to aspects of the present invention;

[0011] FIG. 3 illustrates indicator markings indicating a range of positions of forks of an exemplary adjustable pallet jack according to aspects of the present invention; and

[0012] FIGs. 4 to 11 illustrate various components of an exemplary adjustable pallet jack and illustrate various assembly steps for the assembly of an exemplary adjustable pallet jack according to aspects of the present invention.

Detailed Description

[0013] An example of an adjustable pallet jack 100, as illustrated in FIGs. 1A to 3, can have two fork assemblies 110 in communication with a housing assembly 120. The fork assemblies 110 can be adjustable from an open position as illustrated in FIG. 1 A to a close position as illustrated in FIG. IB, and vice-versa, by turning a crank 160 inserted into the housing assembly 120. The adjustable pallet jack 100 can further include a handle assembly 170.

[0014] As illustrated in FIG. 2, the adjustable pallet jack 100 can include a control arm assembly 150 within the housing assembly 120 to which the fork assemblies 110 are each slidably mounted. When the fork assemblies 110 are not being adjusted, the crank 160 can be removed from a crank slot 121 in the housing assembly 120 and stored within the housing assembly 120. The adjustable pallet jack can include a handle assembly 170 for pushing the pallet jack, and the handle assembly 170 can also be connected via a control arm assembly 150 that allows the handle assembly 170 to raise and lower wheel assemblies 118 on the fork assemblies 110.

[0015] As illustrated in FIG. 3, the pallet jack 100 can be adjusted to a range of positions between the open position illustrated in FIG. 1A and the close position in FIG. IB. The pallet jack can include indicator markings 116, 126 on the fork assembly 110 and the housing assembly 120, respectively, to indicate the position of the fork assemblies 110.

[0016] FIGs. 4 to 11 generally illustrate components of the pallet jack 100 illustrated in FIGs. 1 A to 3 and method steps that can be performed to assemble components of the pallet jack 100.

[0017] As illustrated in FIG. 4, each fork assembly illustrated in FIGs. 1 A to 3 can include a fork blade 112 and a threaded guide block 115 attached to the fork blade 112. As illustrated in FIG. 4, the guide block 115 can be attached with screws 115 to the fork blade 112.

[0018] As illustrated in FIG. 5, each fork blade 112 can be slidably attached to a housing base 122. A mating end of each fork blade 112 having a threaded bore can be inserted into the housing base 122 and attached to the housing base 122 with a shoulder screw 136. Each shoulder screw 136 can pass through a respective slot 132. Each slot 132 can be sized to allow each shoulder screw 136 to travel laterally through each slot 132. Each fork blade 112 can move from the open position (as illustrated in FIG. 1 A) when each shoulder screw 136 is positioned near a first, outer end of its associated slot 132 to the close position (as illustrated in FIG. IB) when each should screw 136 is positioned near a second, inner end of its associated slot 132.

[0019] As illustrated in FIG. 5, the housing base 122 can further include slots 134 for receiving each threaded guide block 114. The slots 134 can be sized to allow each threaded guide block 114 to travel laterally through each slot 134. Each fork blade 112 can move from the open position (as illustrated in FIG. 1 A) when each threaded guide block 114 is positioned near a first, outer end of its associated slot 134 to the closed position (as illustrated in FIG. IB) when each threaded guide block 114 is positioned near a second, inner end of its associated slot 134.

[0020] The housing base 122 can further include crank brackets 124 for holding a crank as illustrated in FIG. 2 and can further include a central guide block 128 that can be attached by screws 129 to the housing base 122.

[0021] FIG. 6 is an exploded view of components of the adjustable pallet jack 100 from a perspective like that of FIG. 2. FIG. 7 is a closer view of some of the components illustrated in FIG. 6. In FIGs. 6 and 7, the housing assembly 120 is shown following the engagement of the shoulder screws 136 to the fork blades 112 to form sliding attachments between the fork blades and the housing base 122.

[0022] Referring collectively to FIGs. 6 and 7, a pair of threaded rods 148 can each be inserted into the housing base 122 through an associated crank slot 121 and held in place by the threaded guide blocks 114, the central guide block 128, a pair of rod guides 138, and a small c-clip 144. Each threaded guide block 114 can have a threaded bore and a non-threaded bore, each central guide block 128 can have two non-threaded bores, and each pair of rod guides 138 can have two non-threaded bores. The housing base 122 can have a crank slot 121 on either side of the base 122, one for each threaded rod 148. [0023] Each threaded rod 148 can be inserted into its associated crank slot 121, slid through a nonthreaded bore of a first rod guide 138, slid through a non-threaded bore of a first threaded guide block 114, slid through a non-threaded bore of the central guide block 128, twisted through a threaded bore of a second threaded guide block 114, and inserted into a second non-threaded bore of a second rod guide 138.

[0024] For each rod guide 138 the associated first non-threaded bore can be positioned adjacent a crank slot 121 and the associated second non-threaded bore can be positioned such that the housing base 122 covers an outer side of the bore, preventing the associated threaded rod 148 from exiting out of the housing base 122 on the side opposite the threaded rod’s 148 associated crank slot 121. Once inserted, each small c-clip 144 can be attached to its associated threaded rod 148 adjacent to the first rod guide 138 inside of the housing base 122. The c-clip 144 can therefore prevent its associated threaded rod 148 from exiting the housing base 122 through the associated crank slot 121. In other words, lateral movement of each threaded rod can be inhibited by inserting a tip of each threaded rod 148 into a covered non-threaded bore of a rod guide 138 positioned opposite the threaded rod’s 148 associate crank slot 121 and attaching a c-clip 144 to the threaded rod 148 directly inside of a rod guide 138 positing adjacent the threaded rod’s associate crank slot 121. Configured thusly, each threaded rod 148 is held in place but capable of rotating.

[0025] The end of each threaded rod 138 accessible from its associated crank slot 121 can be shaped to mate with a crank 160 (e.g. as illustrated in FIGs. 1A and IB). Turning an attached crank 160 can result in a rotation of the associated threaded rod 148.

[0026] FIG. 8 illustrates each threaded rod 148, threaded guide blocks 114, and central guide configured after assembly as described. When a threaded rod 148 is rotated, threads on a threaded portion 149 of the threaded rod 148 rotate within a threaded bore of a threaded guide block 114, causing the threaded guide block 114 to travel along a length of the threaded portion 149. Because each fork blade 112 is attached to a threaded guide block 114 (as illustrated in FIG. 4), movement of the associated threaded guide block 114 results in a movement of the fork blade 112.

[0027] As illustrated in FIGs. 2 and 6, the adjustable pallet jack can include a handle assembly 170 for pushing the pallet jack and for lowering and raising wheel assemblies 118. Attachment of the handle assembly 170 to the fork assemblies 110 can be made with a control arm assembly 150, components of which are shown in an exploded view in FIGs. 6 and 7, and movement of which is illustrated in FIGs. 9 A and 9B.

[0028] As illustrated in FIGs. 6 and 7, with greater detail in FIG. 7, the control arm assembly 150 can include a pair of adjustable pivot forks 152 slidably fitted around a pivot bar 156. A top plate 158 can be attached to each pivot fork 152 to surround the pivot bar 156. Each top plate 158 can be attached with screws 157. The control arm assembly can include a pair of pivot arms 154 each attached to one of a pair of arm supports 153, and the arm supports 153 can come together at the pivot bar 156 and be joined to the pivot bar 156 by a center support 155.

[0029] Referring to FIGs. 6 and 7, once assembled, each pivot fork 152 can each be inserted into one of a pair of slots 135 in the housing base 122. Each of the slots 135 can be sized to allow each pivot fork 152 to travel laterally through each slot 135. Each pivot fork 152 can move from the open position (as illustrated in FIGs. 1A and 9A) when each pivot fork 152 is positioned near a first, outer end of its associated slot 135 to the closed position (as illustrated in FIG. IB and 9B) when each pivot fork 152 is positioned near a second, inner end of its associated slot 135. Once the assembled control arm assembly 150 (as illustrated in FIGs. 9A and 9B) is in place, an axel 146 can be fed through a hole in the housing base through the pivot bar 156 of the control arm assembly 150. A pair of large c-clips 142 can be placed, one on each side of the axel 145 outside of the housing base 122, to prevent movement of the axel 146. Holes in the housing base 122 through which the axel 146 pass can each be protected by a bushing 145. [0030] Referring to FIG. 6, a pair of pins 172 can be used to attach the control arm assembly to the handle assembly 170.

[0031] As illustrated in FIGs. 10A and 10B, each fork assembly 110 can include a connecting rod 164 that connects the associated wheel assembly 118 to the associated pivot fork 152. As illustrated in FIG. 10B, the connecting rod 164 can connect to the pivot fork 152 with a pin, such that the pivot fork 152 and the connection rod 164 have some freedom of rotation about the pin so that when the pivot fork 152 pivots forward or backwards, the connecting rod 164 can move to raise or lower the associated wheel assembly 118.

[0032] FIG. 11 illustrates an exploded view of a wheel assembly 118.

[0033] The descriptions contained herein are examples of embodiments of the invention and are not intended in any way to limit the scope of the invention. The invention contemplates many variations and modifications of the adjustable pallet jack, including alternative fastening means including screws, welds, rivets, glue, epoxy, and the like, utilizing any number of materials for the construction of components, alternative assembly means, alternative configurations of component parts, etc. These modifications would be apparent to those having ordinary skill in the art to which this invention relates and are intended to be within the scope of the claims.