Tray stacking and buffer system and method of use

• US 7,637,712 B2
• Filed: 03/17/2005
• Issued: 12/29/2009
• Est. Priority Date: 03/17/2005
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Wisniewski, Michael A., Varney, Barton
• Primary Examiner(s): Adams; Gregory W
• Application Number:
  US11/081,742
• Publication Number:
  US 20060219610A1
• Time in Patent Office: 1,748 Days
• Field of Search: 414/788.2, 414/790.9, 414/794.9, 414/618, 414/795.3, 198/347.3, 198/817, 198/801, 221/222
• US Class Current: 414/795.2
• CPC Class Codes: B07C 3/008 Means for collecting objects, e.g. containers for sorted mail items pile receivers in general B65H31/00
• CPC Class Codes: B65G 57/165 nested
• CPC Class Codes: B65G 57/302 added articles being lifted to substantially stationary grippers or holders
• CPC Class Codes: B65G 59/066 by means of rotary devices or endless elements
• CPC Class Codes: B65G 60/00 Simultaneously or alternatively stacking and de-stacking of articles

Abstract

A system and method for stacking and storing a plurality of trays includes a stacker system and a buffer system. The stacker system includes a component, e.g., a platform, which moves a tray between a raised position and a lowered position. The buffer system includes a plurality of opposing projections for capturing the tray when the component is in the raised position.

Claims

1. A system for stacking and storing a plurality of trays, comprising:

a stacker system having a platform mounted to a movable frame member, wherein at least the platform moves a tray between a raised position and a lowered position by a lifting and lowering mechanism;

a buffer system having a plurality of opposing projections projecting from opposing belts which are configured to capture the tray when the platform is raised from the lowered position to the raised position; and

a component mounted between the frame member and the platform which is configured to be moved upward when the platform is in the raised position to maintain or hold the tray in a position until it is captured by opposing projections projecting from the opposing belts;

wherein the component is a biasing system which is structured to maintain positive control of the tray and prevent compaction of nested trays of the plurality of trays already within the buffer system.

2. The system of claim 1, wherein the biasing system is a spring system.

3. The system of claim 2, wherein the spring system allows the platform to move, upwards, maintaining the tray in a position until it is captured by a set of the plurality of opposing projections.

4. The system of claim 1, wherein:

the buffer system comprises an opposing belt driven system; and

the plurality of opposing projections extend, inwardly, from driven belts of the opposing belt driven system at a predefined separation from one another.

5. The system of claim 4, wherein the opposing belt driven system comprises:

a first driven belt;

a second, opposing driven belt; and

a single drive system for synchronously driving the first and second, opposing driven belts.

6. The system of claim 5, wherein the buffer system further comprises at least one stop mechanism to maintain a position of the tray when the tray is the raised position and prior to being captured by a set of the opposing projections.

7. The system of claim 1, wherein the stacker system comprises:

a first member;

a platform mounted to the first member by a spring; and

a drive system for moving the platform between the raised position and the lowered position.

8. The system of claim 1, further comprising a controller to coordinate movement of the stacker system and the buffer system.

9. The system of claim 1, further comprising a push arm to push the tray from a conveyor onto the component when the platform is in the lowered position.

10. The system of claim 1, further comprising a push arm or drive mechanism to push the tray from the platform to a conveyor.

11. The system of claim 1, wherein:

the buffer system includes opposing belts, each of the opposing belts include the plurality of opposing projections for engaging a portion of the tray on opposing sides of the tray; and

at least one set of the plurality of opposing projections is positioned to not interfere with the tray as it is moved into the raised position and is moveable into engagement with the tray when the tray is in the raised position.

12. The system of claim 11, further comprising a controller coordinating, synchronously, the movement of a platform of the component and the opposing belt such that:

the platform is moved into the raised position and the at least one set of the plurality of opposing projections are moved to capture the tray when the platform is in the raised position, and

the at least one set of the plurality of opposing projections are moved to load the tray from the buffer system to the platform and the platform is moved to the lowered position.

13. The system of claim 1, wherein the plurality of trays hold mail pieces.

14. The system of claim 1, wherein the movable frame member is a plate, the biasing system is a spring and the spring is mounted between the plate and the platform.

15. The system of claim 14, wherein the plate and the movable frame member move in unison by a same drive mechanism.

16. The system of claim 15, wherein the same drive mechanism is mounted to the plate, and the movement of the plate will move the platform.

17. The system of claim 1, wherein the biasing system is a spring system mounting the platform to a frame member, and further comprising at least one stop mechanism provided on the opposing belts to maintain a position of the tray when the tray is in a second position and prior to being captured by the opposing projections projecting.

18. A system for stacking and storing trays, comprising:

a platform vertically moveable between a first position and a second position, the platform accommodating a tray;

a first drive system connecting to the platform for raising and lowering the platform between the first position and the second position;

opposing driven belts each of which includes a plurality of spaced apart lugs extending partially inward such that a space is provided between spaced apart lugs on the opposing driven belts, the spaced apart lugs being structured for capturing and storing the trays in a vertical, nested configuration;

a second drive system connecting to the opposing driven belts for synchronously rotating the belts of the opposing driven belts in opposing directions;

a controller coordinating the movement of the opposing driven belts and the platform such that the platform is in the second position and the plurality of spaced apart lugs capture and lift the trays from the platform in a vertical, nested configuration;

a spring system mounting the platform to a frame member, the spring system structured to prevent compaction of nested trays; and

at least one stop mechanism provided on the opposing driven belts to maintain a position of the tray when the tray is the second position and prior to being captured by the plurality of spaced apart lugs.

19. The system for stacking and storing trays of claim 18, wherein the controller coordinates the movement of the opposing driven belts and the platform such that:

the platform with a tray thereon is moved into the second position;

the opposing driven belts are rotated in a first direction such that the tray is engaged with the opposing lugs of the plurality of spaced apart lugs on each of the opposing driven belts when the platform is in the second position; and

the platform is lowered into the first position in order to place another tray on the platform.

20. The system for stacking and storing trays of claim 18, wherein the controller coordinates the movement of the opposing driven belts and the platform such that:

an empty platform is moved into the second position;

the opposing driven belts are rotated in a second direction to disengage some of the plurality of spaced apart lugs from the tray when the platform is in the second position; and

the tray is loaded onto the platform and the platform is moved into the first position and the tray is removed from the platform.

21. The system for stacking and storing trays of claim 18, further comprising:

a push arm to push the tray from a conveyor onto the platform when the platform is in the first position; and

a second push arm or driven mechanism to push the tray from the platform to the conveyor.

22. A system for stacking and storing trays, comprising:

a platform vertically moveable between a first position and a second position, the platform accommodating a tray;

a first drive system connecting to the platform for raising and lowering the platform between the first position and the second position;

opposing driven belts each of which includes a plurality of spaced apart lugs extending partially inward such that a space is provided between spaced apart lugs on the opposing driven belts, the spaced apart lugs being structured for capturing and storing the trays in a vertical, nested configuration;

a second drive system connecting to the opposing driven belts for synchronously rotating the belts of the opposing driven belts in opposing directions; and

a controller coordinating the movement of the opposing driven belts and the platform such that the platform is in the second position and the plurality of spaced apart lugs capture and lift the trays from the platform in a vertical, nested configuration, wherein;

the first drive system is a belt drive coupled to the frame or platform for moving the platform between the raised and lowered position;

the opposing driven belts include a first driven belt mounted between a first set of shafts and a second driven belt mounted between a second set of shafts;

the second drive system includes a single drive shaft for synchronously driving the first and second driven belt;

the plurality of spaced apart lugs project towards each other when positioned between the opposing driven belts; and

the plurality of spaced apart lugs are spaced at a predefined separation from one another on each of the opposing driven belts.

23. A method of buffering trays, comprising:

providing a tray onto a single platform which is mounted on a plate which is raised and lowered;

raising the platform with the tray to a stop mechanism;

biasing during raising the platform with a biasing system mounted between the platform and the plate;

synchronizing movement of a belt system of a buffering system with the raising of the tray such that when the tray is in the raised position, the tray will be captured between opposing lugs of the belt system of the buffering system; and

lifting the tray from the platform and into the buffering system by engaging the opposing lugs with the tray such that trays become nested.

24. The method of claim 23, further comprising:

lowering the platform;

placing another tray on the platform;

raising the another tray until it is partly nested with the tray;

synchronizing movement of the buffering system with the raising of the another tray such that when the another tray is in the raised position, the another tray will be captured by the buffering system; and

lifting the another tray from the platform and further nested the another tray with the tray.