Stack loading and unloading cart

• US 20050191159A1
• Filed: 02/26/2004
• Published: 09/01/2005
• Est. Priority Date: 02/26/2004
• Status: Active Grant

• Current Assignee: Benko Engineering, Inc.
• Original Assignee: Benko Engineering, Inc.
• Inventors: Benko, John C.
• Granted Patent: US 7,645,108 B2
• Time in Patent Office: Days
• US Class Current: 414/490
• CPC Class Codes: B62B 1/125 by means of telescoping elements
• CPC Class Codes: B62B 2203/13 comprising a self levelling surface

Abstract

A cart includes a projecting load receiving platform mounted on a slide frame in turn mounted for vertical movement on a main frame. A spring mechanism urges the slide frame and platform to an elevated position so that objects may be stacked on the platform without placing them on the floor. As the weight of the stack on the platform increases the platform starts to descend until the cart is full. Conversely as items are removed from the top of the stack the platform elevates so the operator doesn'"'"'t have to pick up an object from the floor. The spring mechanism uses a plurality of air springs each with a different load rating and operating in a cascading fashion. A pivoting weight operated latch holds the platform in its bottom position until released by a kick plate.

Claims

1. A loading and unloading cart comprising a platform, and means supporting said platform for incremental vertical movement in response to the weight placed on or removed from the platform.

2. A cart as set forth in claim 1 including a main frame, and a slide frame supporting said platform mounted for movement on said main frame.

3. A cart as set forth in claim 2 including cascading gas springs urging said slide frame to an elevated position.

4. A cart as set forth in claim 3 including at least three such gas springs.

5. A cart as set forth in claim 4 including a different load rating for each spring.

6. A cart as set forth in claim 5 including a fixed bottom plate on said main frame and a top plate on said slide frame, and a slide block assembly intermediate said bottom and top plates and connected to said plates by respective gas springs.

7. A cart as set forth in claim 6 wherein said slide block assembly includes relatively movable parts, and a gas spring interconnecting said parts.

8. A cart as set forth in claim 7 wherein each relatively movable part includes two slide blocks, and tie rods connecting and spacing the two slide blocks of each part.

9. A cart as set forth in claim 8 wherein at least one slide block of each part is mounted for movement within the other part.

10. A cart as set forth in claim 1 including a latch to lock the platform in its down position.

11. A transfer cart comprising a platform, adapted to support a stack of objects, said platform normally being at an elevated position, and means responsive to weight being placed on said platform to move the platform incrementally downwardly.

12. A cart as set forth in claim 11 wherein said platform when fully loaded is normally at its lowermost position, and means responsive to weight being removed from the platform to move the platform incrementally upwardly.

13. A cart as set forth in claim 12 wherein said means responsive comprises a plurality of gas springs.

14. A cart as set forth in claim 13 wherein each gas spring has a different load.

15. A cart as set forth in claim 14 wherein the gas spring controlling the initial increment downwardly has a lower load rating than the gas spring controlling the initial increment upwardly.

16. A cart as set forth in claim 15 including at least three gas springs providing at least two intermediate positions for said platform.

17. A cart as set forth in claim 16 including an intermediate gas spring, and a two part slide block assembly interconnected by said intermediate gas spring.

18. A cart as set forth in claim 17 including a bottom gas spring connected to said two part slide block assembly.

19. A cart as set forth in claim 18 including a top gas spring connected to said two part slide block assembly and said platform.

20. A cart as set forth in claim 11 including a latch operative to hold said platform in its lowermost position.

21. A transfer cart comprising a platform adapted to support a stack of objects, said platform when loaded being in a lower position, and means responsive to objects being removed from the stack to move the platform upwardly incrementally.

22. A cart as set forth in claim 21 including a cascading gas spring assembly for moving the stack upwardly as objects are removed from the stack.

23. A cart as set forth in claim 22 wherein said cart includes a main frame, wheels and a stabilizing plate on the lower end of said main frame, and a slide frame supporting said platform for vertical movement on said main frame.

24. A cart as set forth in claim 21 including a latch optionally to hold said platform in said lower position.

25. A transfer cart comprising a platform, a plurality of springs urging said platform upwardly, said springs each being rated differently whereby when one or more objects of a certain weight is placed on said platform, one spring will yield, and when one or more further objects are placed on said platform another spring will yield, and so forth until the cart is full, and said platform is in its lowermost position.

26. A cart as set forth in claim 25 including at least three such springs providing at least two intermediate positions for said platform.

27. A cart as set forth in claim 26 wherein said springs are gas springs.

28. A cart as set forth in claim 27 wherein said gas springs are arranged in vertical order with the lowermost having the highest rating and vice versa.

29. A transfer cart comprising a stack receiving platform, a plurality of springs urging said platform upwardly and each being compressed when said platform is fully loaded, said springs each being rated differently whereby when the top item or items are removed from the stack, the stack will be elevated to present the next item or items in the stack at the elevation of the top items.

30. A cart as set forth in claim 29 including at least three springs providing two intermediate positions for said platform between the uppermost and lowermost positions.

31. A cart adapted to receive a stacked load, comprising a vertically movable platform, a frame supporting said platform in an elevated position, and weight responsive means operative to lower said platform incrementally in response to building a stack on said platform.

32. A cart as set forth in claim 31 including a latch automatically to lock said platform in its lowermost position when it achieves such position.

33. A cart as set forth in claim 32 including a foot operated release for said latch.

34. A cart as set forth in claim 33 wherein said latch is pivoted and weight operated to engage the platform.

35. A cart adapted to receive a stacked load, comprising a vertically movable platform, a frame supporting said platform and the stack thereon in a lower position, and weight responsive means operative to raise said platform incrementally in response to removal of items from the stack.