IN THE UNITED STATES PATENT AND TRADEMARK OFFICE

Patent Application Under 37 C.F.R. §1.53(b)

for

PALLET STOP FOR PALLET LOAD TRANSPORT SYSTEM

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application No. 60/743,747, filed March 24, 2006, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to material handling systems and technology, and, more particularly, to a pallet stop for use in a pallet load transport system for moving pallet loads from a pick-up location to a deposit location.

In one common application of such a pallet load transport system, a pallet load is picked up from a mainline conveyor and deposited at an automatic storage and retrieval (ASRS) crane interface station. Alternatively, a pallet load may be picked up at the crane interface station and deposited onto the mainline conveyor. In any event, the pallet load system includes a shuttle car

that moves between the mainline conveyor and the crane interface station to transport the pallet load.

In pallet load transport systems of the prior art, there is a pick-up and delivery (P&D) shuttle car that transports a pallet load between a mainline conveyor and a crane interface station. Specifically, the shuttle car is supported by and moves along a track between the mainline conveyor and the crane interface station. The shuttle car itself is generally comprised of a lower carriage and an upper carriage (or lift assembly), and the upper carriage can be raised or lowered relative to the lower carriage. Accordingly, as the shuttle car carries a pallet load between the mainline conveyor and the crane interface station, the upper carriage is commonly in a raised position relative to the lower carriage, but as the shuttle car approaches the mainline conveyor or the crane interface station, it is in a lowered position to pick-up or deposit a pallet load.

Furthermore, such prior art systems often include a spring-actuated pallet stop that is forced downward against the spring force as the pallet load moved over an upper surface of the stop. Once the pallet load clears the stop, the spring force causes the stop to raise and prevent the pallet load from moving back over the stop. However, because of the nature of the spring force, the upward force on the pallet load increases as it moved over the stop and the spring is further extended. Such increased upward force could actually cause the pallet load to be forced upward and off of the shuttle car, especially if the pallet load was unusually light. Additionally, because of the constant sliding motion of the pallet load over such a spring-loaded stop, wear can prove to be a problem, and the stop often gradually shifts position, making it less effective in ensuring proper positioning of a pallet load. Thus, there remains a need for an effective and reliable pallet stop for use with pallet load transport systems.

SUMMARY OF THE INVENTION

The present invention is a pallet stop for use in a pallet load transport system for moving pallet loads from a pick-up location to a deposit location.

An exemplary pallet stop in accordance with the present invention generally comprises a support frame, an internal (removable) enclosure secured to and housed within the support frame, a rotating actuator, a pivoting stop operably linked to the rotating actuator, and a counterweight assembly operably linked to the pivoting stop.

The rotating actuator has an upper arm portion that extends just above a surface of the enclosure and at an angle relative to the surface. As a pallet load moves over the surface of the enclosure, its leading edge will contact the upper arm portion of the rotating actuator, which causes it to rotate clockwise about a pivot axis. A lower portion of the rotating actuator is positioned below the pivoting stop. Accordingly, as the rotating actuator rotates clockwise about the pivot axis, the lower portion of the rotating actuator moves downwardly, thus allowing a counterclockwise rotation of the pivoting stop about a pivot axis. In other words, in an upright position, the lower portion of the rotating actuator supports and prevents movement of the pivoting stop, but once the rotating actuator is rotated out of the way, the weight of the pivoting stop causes it to drop into the enclosure and out of the path of travel of the pallet load.

Once the pallet load travels completely over the rotating actuator, the counterweight assembly causes the rotating actuator to return to the upright position. In this regard, the force of the counterweight acts around the circumference of a sprocket operably connected to and rotating with the rotating actuator. Specifically, a chain is operably connected to and engages the sprocket, and a weight is operably connected to a distal end of this chain. This counterweight assembly thus causes the counterclockwise rotation of the rotating actuator back to the upright

position as soon as there is no more force applied to the upper arm portion of the rotating actuator. As the rotating actuator returns to the upright position, the pivoting stop also returns to its upright position, engaging and preventing any further movement of the pallet load. Accordingly, proper positioning of a pallet load is ensured.

DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view of a pallet load transport system including pallet stops made in accordance with the present invention;

Figure 2 is a perspective view of a pallet stop of the pallet load transport system of Figure

i;

Figure 3 A is a side view of the pallet stop of Figure 2 with its exterior wall removed to show internal components and illustrating the pallet stop in an upright position; and

Figure 3B is a side view of the pallet stop of Figure 2 with its exterior wall removed to show internal components and illustrating the pallet stop in a retracted position.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a pallet stop for use in a pallet load transport system for moving pallet loads from a pick-up location to a deposit location.

At the outset, it should be recognized that a pallet load transport system 100 utilized with the present invention operates in the same general manner as prior art constructions as discussed above. Specifically, and as illustrated in Figure 1, the pallet load transport system 100 includes a shuttle car 102 that is supported by and moves along a track 104 between the mainline conveyor 106 and the crane interface station 108. The shuttle car 102 generally comprises a lower carriage

(not shown) and an upper carriage 112, with the upper carriage 112 able to be raised or lowered relative to the lower carriage. Accordingly, as the shuttle car 102 carries a pallet load (not shown) between the mainline conveyor 106 and the crane interface station 108, the upper carriage 112 is commonly in a raised position relative to the lower carriage. As the shuttle car 102 approaches the mainline conveyor 106 or the crane interface station 108, it is in a lowered position to pick-up or deposit a pallet load.

In order to ensure the proper positioning of a pallet load at the crane interface station 108 or at the mainline conveyor 106, the pallet load transport system 100 includes one or more pallet stops 10, 10'. Referring now to Figures 2, 3 A, and 3B, an exemplary pallet stop 10 made in accordance with the present invention generally comprises a support frame 12, an internal (removable) enclosure 14 secured to and housed within the support frame 12, a rotating actuator 16, a pivoting stop 18 operably linked to the rotating actuator 16, and a counterweight assembly 20 operably linked to the rotating actuator 16. Of course, and as illustrated in Figure 1, such a pallet stop 10, 10' is preferably positioned on either side of the track 104 near the crane interface station 108 or the mainline conveyor 106. This can be accomplished by securing the support frame 12 to the outer rails of the track 104 for the shuttle car 102, similar to the positioning of prior art pallet stops, as illustrated in Figure 1. In this particular example, the pallet stops 10, 10' are arranged to ensure the proper positioning of a pallet load at the crane interface station 108, with pallet loads traveling from the mainline conveyor 106 to the crane interface station 108.

Referring again to Figures 3 A and 3B, the rotating actuator 16 has an upper arm portion 16a that extends just above a surface of the enclosure 14, and in this example, at a 60° angle relative to the surface. In this regard, it should be noted that the enclosure 14 houses the rotating actuator 16 and pivoting stop 18. The enclosure 14 is received in and supported by the support

frame 12 and may be characterized as "modular" in that it is designed for ready removal for maintenance or replacement.

Referring still to Figures 3 A and 3B, as a pallet load 200 moves over the surface of the enclosure 14 (from left to right in Figures 3 A and 3B), its leading edge will contact the upper arm portion 16a of the rotating actuator 16, which causes it to rotate clockwise about a pivot axis 22. A lower portion 16b of the rotating actuator 16 is positioned below the pivoting stop 18. Accordingly, as the rotating actuator 16 rotates clockwise about the pivot axis 22, the lower portion 16b of the rotating actuator 16 moves downwardly, thus allowing a counterclockwise rotation of the pivoting stop 18 about a pivot axis 24. In other words, in an upright position, the lower portion 16b of the rotating actuator 16 supports and prevents movement of the pivoting stop 18 (i.e., a locked position), but once the rotating actuator 16 is rotated out of the way, the weight of the pivoting stop 18 causes it to drop substantially into the enclosure 14 and out of the path of travel of the pallet load 200, as illustrated in Figure 3B.

Once the pallet load 200 travels completely over the rotating actuator 16, the counterweight assembly 20 causes the rotating actuator 16 to return to the upright position, as illustrated in Figure 3 A. In this regard, the force of the counterweight assembly 20 acts around the circumference of a sprocket 17 operably connected to and rotating with the rotating actuator 16. Specifically, a chain 19 is operably connected to and engages the sprocket 17, and a weight 21 is operably connected to a distal end of this chain 19. This counterweight assembly 20 thus causes the counterclockwise rotation of the rotating actuator 16 back to the upright position as soon as there is no more force applied to the upper arm portion 16a of the rotating actuator 16. Of course, as the rotating actuator 16 returns to the upright position, the pivoting stop 18 also

returns to its upright position, engaging and preventing any further movement of the pallet load 200. Accordingly, proper positioning of the pallet load 200 is ensured.

As a further refinement, and as illustrated in Figures 3 A and 3B, the center of rotation of the sprocket 17 may be offset from the pivot axis 22 of the rotating actuator 16. As such, the force required to initially "push" and start the clockwise rotation of the rotating actuator 16 is minimal, but the force increases as the clockwise rotation continues. Accordingly, once the pallet load 200 travels completely over the rotating actuator 16, the counterweight assembly 20 will cause a rapid return of the rotating actuator 16 to the upright position.

Alternatively, and as mentioned above, it is contemplated that such a pallet stop could be used not only at the crane interface station, but also at the mainline conveyor. In this regard, each pallet stop would be positioned with the face of the pivoting stop along the edge of the effective width of the mainline conveyor.

One of ordinary skill in the art will recognize that additional embodiments are also possible without departing from the teachings of the present invention. This detailed description, and particularly the specific details of the exemplary embodiment disclosed therein, is given primarily for clarity of understanding, and no unnecessary limitations are to be understood therefrom, for modifications will become obvious to those skilled in the art upon reading this disclosure and may be made without departing from the spirit or scope of the invention.