Abstract:
A plurality of robots are positioned on a rotatable table for transporting parts to be processed through a plurality of work stations positioned around the periphery of the table. Each robot can carry a workpiece from one work station to the next. The rotation of the table moves the robot from one workstation to the next while carrying a part to be processed. Each robot can be independently movable relative to the other robots and each robot can be independently movable relative to the table. Each robot can include a welder for processing the workpiece independent of the workstation or during movement between work stations. Each robot can carry a plurality of differently configured workpieces between the work stations.

Description:
This application claims priority to provisional application No. 60/197,614 filed Apr. 18, 2000. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a plurality of robots positioned on a turntable at spaced locations along the periphery, where the turntable is movable in rotation to predetermined angular positions independently of movement of the individual robots disposed thereon. 
     BACKGROUND OF THE INVENTION 
     A modular robotic finishing work center is disclosed in U.S. Pat. No. 4,644,897. The patent discloses an elevated platform with a turntable mounted thereon which is rotatable about a vertical axis, and a robot manipulator fixedly mounted relative to the vertical axis, wherein the turntable ends are rotatable through a circular path where at least part of the path includes a partially protected booth for collecting paint residue and overspray. The robot manipulator has a movable arm and spray applicator capable of movement along a limited range so as to provide a predetermined envelope of possible work areas for spray finishing, where a portion of the turntable end path and at least a portion of the spray booth are included within this envelope. 
     A tool turntable for a manufacturing system is disclosed in U.S. Pat. No. 5,186,304. The production line manufacturing system includes a programmable multi-position rotatable unit that can be used in each of the work stations to accommodate both changes in workpieces to be processed and tools. The rotatable unit includes a four-position horizontally arranged fixture table including four vertically arranged fixtures movably mounted thereon. A precision locator key on each of the fixtures positions each individual fixture on the table and also serves as a positive fixture stopped in the work position. 
     SUMMARY OF THE INVENTION 
     It would be desirable in the present invention to provide a turntable or a carousel with a plurality of robots positioned thereon in peripherally spaced locations with respect to one another for movement about a vertical axis of the turntable while allowing independent movement of each of the individual robots positioned thereon. The apparatus for manufacturing parts according to the present invention can include a turntable having an outer periphery and a centrally located axis of rotation, a plurality of robots positioned at peripherally spaced locations about the turntable with respect to one another for independent movement with respect to one another and with respect to movement of the turntable, and a control system for controlling and synchronizing independent individual movements of the robots with rotation of the turntable to move each individual robot from one work station at a first angular position to another work station at a second angular position. 
     Other objects, advantages and applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
     FIG. 1 is a simplified plan view of a robotic turntable or carousel according to the present invention for manufacturing parts; and 
     FIG. 2 is a side elevational view of a robotic turntable according to the present invention including a plurality of robots individually operating with respect to different work stations on opposite sides of the turntable. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An apparatus  10  according to the present invention provides for the manufacturing of parts  12  by a plurality of robots  14  positioned on a turntable  16  for rotation about an axis  18 . The robots are positioned at different locations spaced along the outer periphery of the turntable  16 . In the illustrated embodiment, there are an equal number of robots  14  to the number of work stations  20  positioned around the periphery of the turntable  16 , although an equal number of robots to work stations is not required to practice the present invention. By way of example, and not limitation, the present invention will be described in detail with respect to the manufacture of particular parts  12 , such as a side panel sub assembly of a motor vehicle. 
     Referring now to FIG. 1, the turntable  16  is illustrated having eight robots  14   a ,  14   b ,  14   c ,  14   d ,  14   e ,  14   f ,  14   g ,  14   h  disposed at evenly spaced angular positions around the outer peripheral edge of the turntable  16 . The robots  14   a - 14   h  are independently movable with respect to one another, and are movable independent of movement of the turntable  16 . When the turntable  16  is disposed at a first angular position, such as that illustrated in FIG. 1, each robot  14  is capable of performing various independent work cycles at the individual work station  20  corresponding to its current location. By way of example and not limitation, in the position illustrated in FIG. 1, the robot  14   a  is positioned at work station  20   a  for unloading parts that have been processed. After unloading a part, the turntable  16  can be rotated about the axis  18  to now position the robot  14   a  at the position previously occupied by robot  14   b . In this position, the robot has access to a tool change work station  20   b  in order to provide the opportunity to change the tooling as required for the particular part to be processed next. 
     After completion of the tool change, if any, at work station  20   b , the turntable  16  can be rotated again about the axis  18  to move the robot  14   a  from the position previously shown for robot  14   b  to the position previously shown for robot  14   c . When in this position, the robot can pick up a part to be processed at the part loading fixture  22  at work station  20   c . Preferably, the fixture  22  located at the work station  20   c  is an indexing part load fixture  22   c  capable of positioning a plurality of fixtures corresponding to the desired body style and model to be processed through the work station  20   c . In its most preferred configuration, the indexing fixture  22   c  includes four different fixtures positioned on four major surfaces of a rectangular fixture rotatable about a horizontal axis to position one of the four major surfaces in an upright ready position for receiving parts to be loaded onto or picked up by the robot at work station  20   c.    
     After the robot has retrieved the part to be processed from the work station  20   c , the turntable  16  is rotated about the axis  18  to bring the robot  14   a  into the position previously illustrated for robot  14   d  corresponding to work station  20   d . At work station  20   d , the robot  14   a  positions the part  12  into the fixture  22   d  allowing additional work to be performed on the part. The fixture  22   d  is preferably an indexing part fixture similar to fixture  22   c . The fixture  22   d  preferably has four major surfaces with different fixtures for various models and body styles to be processed. The fixture is rotatable about a horizontal axis to bring a selected one of the four major surfaces into an upright ready position for receiving the next part to be processed. The additional work can include the attachment and assembly of various sub components to the part, or the clamping and welding of various components at different positions on the part, or any other automated processing required with respect to the particular part being processed through the apparatus  10  according to the present invention. The processing can include assembly and/or welding by additional robots  24   a - 24   d  disposed at work station  20   d . One or more robots  24  can be positioned at the work station  20   d  as required for the particular part processing to take place at the particular work station. After the processing of the part is completed at work station  20   d  and the robot  14   a  retrieves the part from the fixture  22   d , the turntable  16  is rotated about the axis  18  to move the robot  14   a  to the position previously illustrated for robot  14   e . At this position, additional processing can take place as required for the particular part. By way of example and not limitation, the illustration shows a respot work station  20   e  for welding areas of the part inaccessible while resting in the fixture  22   d  of work station  20   d . A respot welder  26  can be positioned at each respot work station, such as welder  26   e  at work station  20   e.    
     After respotting has been completed at the work station  20   e , the turntable  16  can be rotated about axis  18  to position the robot  14   a  in the position previously shown for robot  14   f . The part can be loaded by the robot into the fixture  22   f  at the work station  20   f . The fixture  22   f  preferably can be an indexing part fixture similar to  22   d  and  22   c  previously described. In the most preferred configuration, the indexing part fixture  22   f  is provided as a rectangular fixture having four major surfaces with different fixtures for the various models and body styles to be processed through the apparatus  10  according to the present invention. The rectangular fixture is rotatable about a horizontal axis to bring a selected one of the four major fixture surfaces into an upright ready position for receiving the part to be processed. The processing at the work station  20   f  can include assembly of additional sub components to the primary part being assembled, or additional clamping and welding of various portions of the part to one another. Additional robots  26   a - 26   d  can be provided at the work station  20   f  to perform the assembly or welding operations as required. 
     When processing of the part has been completed at the work station  20   f , the turntable  16  can be rotated about the axis  18  to position the robot  14   a  at the position previously illustrated for robot  14   g . Additional processing of the part can take place at work station  20   g  when the robot is in this position. By way of example and not limitation, a respot welding apparatus  26   g  can be provided to weld portions of the part  12  being assembled that could not be accessed while the part was positioned in the fixture at work station  20   f.    
     After respotting has been completed, the turntable  16  can be rotated about the axis  18  to position the robot  14   a  at the position previously illustrated for robot  14   h . At this position, the part can be subjected to additional processing, by way of example and not limitation, such as additional respot welding by a respot welding apparatus  26   h  at work station  20   h . When the additional processing is completed at work station  20   h , the turntable  16  can be rotated about the axis  18  to again bring the robot  14   a  to the position illustrated as  14   a  in FIG. 1 where the processed part can be unloaded at the work station  20   a.    
     While the invention has been described in detail with respect to a single robot  14   a  being rotated through the various work stations around the periphery of the turntable  16 , it should be apparent to those skilled in the art that the additional robots  14   b ,  14   c ,  14   d ,  14   e ,  14   f ,  14   g ,  14   h  positioned on the turntable  16  perform the same operations at the various work stations while rotated through the various work station positions  20   b ,  20   c ,  20   d ,  20   e ,  20   f ,  20   g ,  20   h , and that work is simultaneously performed at each work station by each of the robots  14   a - 14   h  prior to the turntable being moved to transfer the robots  14   a - 14   h  and parts carried by the robots  14   a - 14   h  to the next work station  20   a - 20   h  in the processing system. 
     Referring now to FIG. 2, a cross-sectional elevational view is shown of the robots  14   d ,  14   f  on the turntable  16  according to the present invention through work station  20   d  and work station  20   f . As previously described, the robots  14   d  and  14   f  can transport workpieces  12  to the work station  20   d  and  20   f  respectively and can load the parts into a corresponding fixture  22   d ,  22   f  for the particular part to be processed. Each of the indexing fixtures  22   d ,  22   f  at the work stations  20   d  and  20   f  can be in the form of a rectangular fixture having four major surfaces with different fixture configurations for the various body styles and models to be processed through the work stations. Each of the fixtures  22  is rotatable about an axis  30  to position the desired fixture in the upright ready position for receiving the part to be delivered by the corresponding robot presently positioned at that work station. Welders  32  can be positioned above each of the robots  14 , as can best be seen in FIG. 2 where welder  32   d  is positioned above robot  14   d  and welder  32   f  is positioned above robot  14   f . The welders  32  positioned above the robots  14  allow additional welding to be performed during a movement cycle of the turntable  16 , or while one work station is waiting for completion of work being performed at another work station. In this way, additional work can be performed by the robot  14  and welder  32  between cycles performed at various work stations. The part can be manipulated and moved as required to perform multiple welds with the welders  32 , or the respot welders  26   e ,  26   g ,  26   h  at the work stations  20   e ,  20   g  and  20   h.    
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.