System for loading or unloading of parts onto or from trays

• US 5,882,174 A
• Filed: 12/13/1996
• Issued: 03/16/1999
• Est. Priority Date: 12/15/1995
• Status: Expired due to Term

• Current Assignee: ATS Automation Tooling Systems Incorporated
• Original Assignee: ATS Automation Tooling Systems Incorporated
• Inventors: Mowat, Donald J., Cybulski, Michael A., Woerner, Klaus D.
• Primary Examiner(s): Bucci, David A.
• Assistant Examiner(s): TRAN, THUY VAN
• Application Number:
  US08/766,352
• Time in Patent Office: 823 Days
• Field of Search: 414/331, 414/340, 414/391, 414/392, 414/395, 414/416, 414/788.7, 414/788.8, 414/793.5, 414/795.8, 414/796.7, 414/796.9, 414/796.5, 414/793.4, 414/609 , 414/751, 414/801
• US Class Current: 414/788.7
• CPC Class Codes: B65G 60/00 Simultaneously or alternatively stacking and de-stacking of articles
• CPC Class Codes: B65G 65/00 Loading or unloading of vehicles B65G67/00

Abstract

The system is for loading or unloading parts onto or from trays. The same system may be used for either function. A stack of trays loaded on a cart is wheeled into a first cart docking bay. A second cart is positioned in a second cart docking bay beside the first bay, to receive processed trays. A first tray elevator lifts the first cart and trays, or just the trays, to align the uppermost tray with a tray singulator and clamping mechanism. The tray is singulated, i.e. first supported at a lip by retractable opposing support rails and then separated from the stack by operation of the elevator to lower the tray stack, and is then clamped in a precise position. It is subsequently unclamped and shuttled laterally into alignment above the second cart, onto identical retractable support rails, where it is similarly clamped in a precise position. The next tray is then raised by the first elevator and singulated and clamped in position, so that there are then two precisely positioned trays, one above each cart and tray stack. A robot loads or unloads parts onto or from trays at either location, transferring the parts from or to a target location, such as a pallet on a conveyor passing through the system, for example. This loading or unloading takes place primarily at the shuttled tray. When the shuttled tray is completely filled or emptied as the case may be, it is unclamped, the second elevator is lifted to provide support for the tray, the singulator mechanism is opened to release the tray, and the tray stack is lowered, thus clearing the way for the next tray to be shuttled across. While the filled or emptied tray is being lowered, the robot can transfer parts to or from the tray above the first stack, thereby minimizing delays in the cycle.

Claims

1. A system for loading or unloading parts onto or from trays, comprising:

a frame defining a first cart bay and an adjacent second cart bay, each for receiving a horizontally transportable cart on which trays are stackable;

an elevator mechanism in each cart bay;

two tray singulating and clamping mechanisms at the same height and aligned with each other, one above each said cart bay, said mechanisms having opposing singulating means for supporting opposite sides of a tray elevated thereto by operation of said elevator and opposing clamping means for clamping said tray, said singulating means being moveable between a retracted position allowing passage of a tray and an actuated position where said tray is supported, said clamping means being similarly moveable between a retracted position allowing passage of a tray and an actuated position where said tray is clamped;

means for transferring an unclamped singulated tray laterally from at least one tray singulating and clamping mechanism towards the other tray singulating and clamping mechanism, and thus from above one cart bay to above the other cart bay;

means for transferring parts between any singulated and clamped tray and another location; and

control means programmed to detect horizontal positioning of the transportable cart in one said cart bay, to raise one said elevator to position an uppermost tray opposite said singulator mechanism above said one cart bay, to then actuate said singulating mechanism to support said tray, to then lower said elevator to separate said tray from any remaining trays in that cart bay, to then actuate said clamping mechanism to clamp said tray, to release said clamping mechanism and to actuate said means to transfer said tray laterally when desired to transfer said tray to said other singulator and clamping mechanism, to clamp said tray at said other singulator and clamping mechanism, to then raise the other elevator to the correct height for receiving said tray from the other singulator mechanism, to retract said other singulator mechanism to allow said other elevator to receive said tray from said other singulator mechanism, to then lower said other elevator and actuate said other singulator mechanism to enable it to support the next transferred tray, and to control said transfer of parts between any singulated and clamped tray and another location.

2. A system as recited in claim 1, further comprising at least one moveable end stop moveable between a retracted position and an actuated position, such that movement of said end stop to said actuated position brings it into contact with a singulated tray to move said tray to a precise lateral position.

3. A system as recited in claim 1, where said elevator raises said trays by raising said cart.

4. A system as recited in claim 1, where said elevator raises said trays by lifting said trays from said cart.

5. A system as recited in claim 1, where said means for transferring parts comprises a robot having a gripper positionable within a three-dimensional operating envelope, said operating envelope including the regions of said singulating and clamping mechanisms and thus trays clamped by said mechanisms, and another region for obtaining or receiving parts to be transferred.

6. A method of operating a system for loading or unloading parts onto or from trays, said system comprising:

a frame defining a first cart bay and an adjacent second cart bay, each for receiving a horizontally transportable cart on which trays are stackable;

an elevator in each cart bay;

two tray singulating and clamping mechanisms at the same height and aligned with each other, one above each said cart bay, said mechanisms having opposing singulating means for supporting opposite sides of a tray elevated thereto by operation of said elevator and opposing clamping means for clamping said tray, said singulating means being moveable between a retracted position allowing passage of a tray and an actuated position where said tray is supported, said clamping means being similarly moveable between a retracted position allowing passage of a tray and an actuated position where said tray is clamped;

means for transferring an unclamped singulated tray laterally from at least one tray singulating and clamping mechanism towards the other tray singulating and clamping mechanism, and thus from above one cart bay to above the other cart bay;

means for transferring parts between any singulated and clamped tray and another location;

said method comprising the steps of detecting horizontal positioning of the transportable cart in one said cart bay;

then raising one said elevator to position an uppermost tray opposite said singulator mechanism above said one cart bay, then actuating said singulating mechanism to support said trays then lowering said elevator to separate said tray from any remaining trays in that cart bay, then actuating said clamping mechanism to clamp said tray, then releasing said clamping mechanism and actuating said means to transfer said tray laterally to said other singulator and clamping mechanism, then clamping said tray at said other mechanism, then raising the other elevator to the correct height for receiving said tray from the other singulator mechanism, then retracting said other singulator mechanism to allow said other elevator to receive said tray from said singulator mechanism, then lowering said other elevator and actuating said other singulator mechanism to enable it to support the next transferred tray, and further comprising transferring of parts between any singulated and clamped tray and another location.

7. A method as recited in claim 6, where said step of transferring parts between any singulated and clamped tray and another location is carried out in a primary phase between said other location and said laterally transferred tray, and in a secondary phase between said other location and a tray which has not yet been laterally transferred, said secondary phase taking place when transfers involving said laterally transferred tray are completed and while said laterally transferred tray is being removed to said second cart bay via operation of said other elevator.