Workpiece processing system

• US 4,982,827 A
• Filed: 01/30/1989
• Issued: 01/08/1991
• Est. Priority Date: 04/01/1985
• Status: Expired due to Fees

• Current Assignee: Globe Products Incorporated
• Original Assignee: Globe Products Incorporated
• Inventors: Finegold, Hyman B., Seitz, David R., Heaton, Mark T.
• Primary Examiner(s): Skaggs, H. Grant
• Assistant Examiner(s): DAYOAN, DARRELL G
• Application Number:
  US07/303,064
• Time in Patent Office: 708 Days
• Field of Search: 198/339.1, 198/340, 198/341, 198/346.1, 198/346.2, 198/370, 198/349, 198/349.1, 198/349.6, 198/349.8, 198/349.95, 198/803.14, 198/803.15 , 198/463.3, 198/349.7, 198/349.9, 414/222, 414/231, 414/232
• US Class Current: 198/341.07
• CPC Class Codes: B23Q 7/035 on which work holders are fixed
• CPC Class Codes: B23Q 7/14 co-ordinated in production lines

Abstract

Workpieces are conveyed from an incoming load station to a plurality of processing machines utilizing an endless conveyor having plural cradles for carrying the workpieces. A seat memory tracks each of the cradles and designates them as either work-to-be-performed cradles or work-finished cradles. The cradles are filled at a load station in accordance with an algorithm by which there is a predetermined ratio between those of the cradles being conveyed from the load station to the first of the processing machines designated as work-to-be-performed cradles and those of the cradles designated as work-finished cradles.

Claims

1. Workpiece processing apparatus for performing processing operations on workpieces comprising:

a plurality of processing machines, each respectively located at a processing station therefor;

an incoming load station;

an outgoing unload station;

an endless conveyor having plural carriers for carrying the workpieces along an endless path passing adjacent said incoming load station, said processing stations and said outgoing unload station;

plural machine load and unload transfer means, each located respectively adjacent each of said processing stations, for delivering workpieces from said carriers to receiving devices at said processing stations in preparation for having processing operations performed thereon and for returning workpieces after performance of the processing operations thereon to said carriers;

said incoming load station having conveyor incoming load transfer means for transferring workpieces prepared to have processing operations performed thereon to said carriers;

said outgoing unload station having conveyor outgoing unload transfer means for transferring workpieces upon which processing operations have been completed from said conveyor to said unload station;

carrier seat memory means for tracking each of said carriers and designating each of said carriers as either (a) a work-to-be-performed carrier or (b) a work-finished carrier;

means signaling said memory means to cause said memory means to designate each of said carriers as a work-to-be-performed carrier when it is filled at said incoming load station, said memory means retaining the work-to-be-performed designation of each of said carriers until it is emptied at a processing station;

means signaling said memory means to cause said memory means to designate each of said carriers as a work-finished carrier when it is emptied at a processing station, said memory means retaining the work-finished designation of each of said carriers until it is filled at said incoming load station with at least one workpiece upon which work is to be performed;

and incoming load logic means for controlling the operation of said incoming load transfer means to cause it to logically fill selected ones of said carriers with workpieces upon which work is to be performed so that the ratio between the number of those of said carriers being conveyed from said incoming load station to the first of said processing stations designated as work-to-be-performed carriers and the number of those of said carriers designated as work-finished carriers is finite and substantially constant.

2. The apparatus of claim 1 wherein said incoming load logic means comprises means responsive to the designations in said memory means of said carrier at said load station and of selected ones of said carriers adjacent said load station for controlling the operation of said incoming load transfer means.

3. The apparatus of claim 1 wherein said memory means tracks and designates each carrier as to whether it is filled or unfilled.

4. The apparatus of claim 1 wherein at least some of said machines operate in a manner to perform substantially identical processing operations on the workpieces.

5. The apparatus of claim 1 wherein said incoming load logic means comprises means for controlling the operation of said incoming load transfer means so that there are more of said carriers being conveyed from said incoming load station to the first of said processing stations designated as work-to-be-performed carriers than work-finished carriers.

6. The apparatus of claim 1 wherein said incoming load logic means controls the operation of said incoming load transfer means so that a workpiece upon which work is to be performed is loaded into an empty carrier at said incoming load station when, and only when, said memory means designates at least one of the last two carriers carried past said incoming load station as a work-finished carrier and a carrier next approaching said incoming load station as a work-finished carrier.

7. Apparatus as claimed in claim 1 and further comprising discriminator means including plural sensing means, each of said sensing means being located adjacent a respective one of said processing stations, for discriminating between empty work-finished carriers and work-finished carriers carrying a workpiece that has had said processing operations performed thereon, said discriminating means producing a signal enabling the machine load and unload transfer means at the respective station to return a workpiece only to an empty work-finished carrier.

8. Workpiece processing apparatus for performing processing operations on workpieces comprising:

a plurality of processing machines, each respectively located at a processing station therefor;

a load and unload station;

an endless conveyor having plural carriers for carrying the workpieces along an endless path passing adjacent said load and unload station and said processing stations;

plural machine load and unload transfer means, each located respectively adjacent each of said processing stations, for delivering workpieces from said carriers to receiving devices at said processing stations in preparation for having processing operations performed thereon and for returning workpieces after performance of the processing operations thereon to said carriers;

said load and unload station having conveyor load transfer means for transferring workpieces prepared to have processing operations performed thereon to said carriers and for transferring workpieces upon which processing operations have been completed from said carriers;

carrier seat memory means for tracking each of said carriers and designating each of said carriers as either (a) a work-to-be-performed carrier or (b) a work-finished carrier;

means signaling said memory means to cause said memory means to designate each of said carriers as a work-to-be-performed carrier when it is filled at said load and unload station, said memory means retaining the work-to-be-performed designation of each of said carriers until it is emptied at a processing station;

means signaling said memory means to cause said memory means to designate each of said carriers as a work-finished carrier when it is emptied at a processing station, said memory means retaining the work-finished designation of each of said carriers until it is filled at said load and unload station;

and incoming load logic means for controlling the operation of said conveyor load transfer means to cause it to logically fill selected ones of said carriers with workpieces upon which work is to be performed so that the ratio between the number of those of said carriers being conveyed from said load and unload station to the first of said processing stations designated as work-to-be-performed carriers and the number of those of said carriers designated as work-finished carriers is finite and substantially constant.

9. The apparatus of claim 8 wherein said incoming load logic means comprises means responsive to the designations in said memory means of said carrier at said load and unload station and of selected ones of said carriers adjacent said load and unload station for controlling the operation of said load transfer means at said load and unload station.

10. The apparatus of claim 8 wherein said memory means tracks and designates each carrier as to whether it is filled or unfilled.

11. The apparatus of claim 8 wherein at least some of said machines operate in a manner to perform substantially identical processing operations on the workpieces.

12. The apparatus of claim 8 wherein said incoming load logic means comprises means for controlling the operation of said load transfer means at said load and unload station so that there are more of said carriers being conveyed from said load and unload station to the first of said processing stations designated as work-to-be-performed carriers than work-finished carriers.

13. The apparatus of claim 8 wherein said incoming load logic means controls the operation of said load transfer means at said load and unload station so that a workpiece upon which work is to be performed is loaded into an empty carrier at said load and unload station when, and only when, said memory means designates at least one of the last two carriers carried past said load and unload station as a work-finished carrier and a carrier next approaching said load and unload station as a work-finished carrier.

14. Apparatus as claimed in claim 8 and further comprising discriminator means including plural sensing means, each of said sensing means being located adjacent a respective one of said processing stations, for discriminating between empty work-finished carriers and work-finished carriers carrying a workpiece that has had said processing operations performed thereon, said discriminating means producing a signal enabling the machine load and unload transfer means at the respective station to return a workpiece only to an empty work-finished carrier.

15. A method of conveying workpieces from an incoming load station to a plurality of processing machines, each respectively located at a processing station therefor, utilizing an endless conveyor having plural carriers for carrying the workpieces along an endless path passing adjacent said incoming load station and said processing stations, the steps of said method comprising:

providing carrier seat memory means for tracking each of said carriers and designating each of said carriers as either (a) a work-to-be-performed carrier or (b) a work-finished carrier;

signaling said memory means to cause said memory means to designate each of said carriers as a work-to-be-performed carrier when it is filled at said incoming load station;

selectively transferring workpieces from work-to-be-performed carriers to said processing machines;

signaling said memory means to cause said memory means to designate each of said carriers as a work-finished carrier when it is emptied at a processing station;

selectively transferring workpieces from said processing machines to work-finished carriers;

continuing to designate a carrier as a work-finished carrier in said memory means until the carrier is again designated a work-to-be-performed carrier when it is again filled at said incoming load station;

and logically filling selected ones of said carriers when at said incoming load station with workpieces upon which work is to be performed so that the ratio between the number of those of said carriers being conveyed from said incoming load station to the first of said processing stations designated as work-to-be-performed carriers and the number of those of said carriers designated as work-finished carriers is finite and substantially constant.

16. The method of claim 15 wherein the filling of said carriers is determined by the designations in said memory means of said carrier at said load station and of selected ones of said carriers adjacent said load station.

17. The method of claim 15 comprising the further step of signaling said memory means as to whether said carriers are filled or unfilled.

18. The method of claim 15 wherein the filling of said carriers is such that of said carriers being conveyed from said incoming load station to the first of said processing stations, more carriers are designated as work-to-be-performed carriers than work-finished carriers.

19. The method of claim 15 wherein the filling of said carriers is such that a workpiece upon which work is to be performed is loaded into an empty carrier at said incoming load station when, and only when, said memory means designates at least one of the last two carriers conveyed past said incoming load station as a work-finished carrier and a carrier next approaching said incoming load station as a work-finished carrier.

20. The method as claimed in claim 19 wherein the step of selectively transferring workpieces from said processing machines to work-finished carriers comprises sensing said carriers for the presence of a workpiece and transferring a workpiece from a processing machine to a work-finished carrier only when it is sensed that the carrier is empty.