Patent Document

BACKGROUND AND SUMMARY OF THE INVENTION  
       [0001]     The present invention relates to devices for controlling delivery of work pieces to welding stations in manufacturing or assembly operations and, more particularly, to an improved system for delivering and positioning on work pieces at production line workstations having stud welding operations.  
       FIELD OF THE INVENTION  
       [0002]     As is well known, assembly or production line facilities require the delivery and temporary storage of large volumes of production parts at or near assembly or production line workstations to support worker line operations on a continuous mass production basis. Automotive production line or assembly line operations in particular require the delivery of large and varying numbers of parts of varying sizes for assembly to automotive or truck vehicles or subsystems thereof, on a continuous basis.  
         [0003]     Due to the fact that mass production operations require the continuous delivery of a large number of such parts during any particular work shift, typical assembly line operations require movement, positioning and temporary storage of large numbers of stackable pallets filled with various components at the production facility. In this regard, various components often require varying automated processing. These process often include spot welding, painting or the welding of weld studs. Often, however similar but not identical processing, requiring a single type of machine, can be conducted on varying types of work pieces. Dedicated machinery however increase the cost and floor space requirements of a production system. Furthermore, a single work piece can require varying processing at various workstations depending on the post processing use of the work piece.  
         [0004]     It is, therefore, desirable to provide a production parts delivery system which facilitates the delivery of fresh pallets or containers of parts to a set of production line work stations as needed. It is also desirable to provide such a system which reads information from the container to trigger a predetermined robotic sequence. It is further desirable to provide such a system which positions full production part containers as desired adjacent a plurality of work stations which have associated robots and fastener welders.  
         [0005]     The present invention is intended to satisfy the above desirable features through the provision of a new and improved stud welding system which is designed in structural modules operative to define a base portion having an input and output portion and an optical scanning system, a shuttle or conveyor for conveying the components in trays to work stations.  
         [0006]     In one embodiment of the invention, a system is provided to regulate the flow of components a direct them to specific processing. The system utilizes a robotic system to move components from a movable tray to a work position configured to weld a fastener onto the component. The robotic system utilizes tracking systems to initiate which work station or work stations the robots will transport the work piece to.  
         [0007]     In another embodiment of the invention, the system utilizes an optical system to trigger a specific robotic sequence. The sequence can incorporate movement of the component either using a robotic arm or by movement of the pallet. The component is moved to one or more work stations which fastens at least one weld fastener to the component using a welding machine. The robot is then configured to move the component to another location for further fastener welding or into a transportable tray.  
         [0008]     The above and other features of the invention will become apparent in the reading of the detailed description of the preferred embodiments, which makes reference to the following sets of drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a top view of a delivery system in accordance with one embodiment of the present invention; and  
         [0010]      FIG. 2  is flow chart describing the control of the system in  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0011]     Referring now specifically to the drawings, a container storage and delivery structure and system in accordance with one embodiment of the present invention is indicated generally in  FIG. 1 . The system  10  is centered around a conveyor system  12 , which is configured to transport various work pieces  14  in stackable component trays  16 . Disposed about the conveyor  12  is a plurality of work stations  18   a - 18   d.  Each work station  18  contains fastener welding equipment  20  configured to weld one or more types of weldable fasteners such as studs or weld nuts onto the various work pieces  14 . Disposed between the work stations  18  are a plurality of robots  22   a - 22   d  which are programmed to transport the work pieces  14  from the stackable trays  16  to the welding equipment  20 . Optionally, the conveyor  10  can be coupled to the work station using a pallet interchange conveyor  23 .  
         [0012]     The conveyor  12  is configured to transport numerous types trays  16 . Each of the varying trays  16  can contain differing types of components or work pieces  14 . Optionally, the varying trays  16  can contain one or more types of components. Each of the trays  16  has a tag  24  which is used by the system  10  to determine which components  14  are within the tray  16 . In this regard, the system  10  has a reader  26  disposed adjacent to the conveyor  12  which reads the tag  24 . The reader  26  can read optical or electromagnetic signatures indicative of the identification tag  24 . The system  10  uses information from the tag  24  to determine which software loop  28  to initiate within a system controller  30 .  
         [0013]     The system controller  30  as a plurality of control program loops  28  which function to control the movement of work pieces  14  through the system  10 . Coordinated together are the conveyor  12 , the robots  22   a - 22   d  and the weld equipment  20 . Depending on the work pieces  14  found in the tray  16 , the conveyor  12  will transport the tray  16  to a given position. A robotic arm  32  of the robot  22  will then grasp one of the work pieces  14  within the tray  16  and move it to a first work station  18 . At the work station  18 , a first weld machine  20  will couple a first weld stud to the work piece  14 . The robotic arm  32  then either indexes the location of the work piece  14  with respect to the stud welder  20  for the fastening of a second stud to the work piece  14 , or returns it to the stackable tray  16 .  
         [0014]     At this point, the instruction set for the indexes the robot arm  32  to recursively perform its operation of the set of work pieces  14  within the stackable trays  16 . As each stackable tray  16  may have different types of work pieces  14  stored within, the robotic sequence of the robotic arm  32  may be different for each work piece  14  within the tray  16 . In this situation, the robot  22  is instructed to retrieve the work piece  14  and position it properly within the welding equipment  20 . The welding equipment  20  is then instructed by the system controller  30  to fasten a weld stud onto the work piece  14 .  
         [0015]     After the processes have been completed on the identified work piece  14  within the stackable trays  16 , the tray  16  is then forwarded to a second station  18   b.  At this point, a second robot functions  20   b  to remove work pieces  14  within the stackable tray  16  and proceeds to position them with respect to a second weld stud machine  20   b.  As with the processes associated with the first location, the system recursively processes the required components within the tray  16 .  
         [0016]     Optionally, the movement of the first tray  16  to the second position  18   b,  allows the system to move a second stackable tray  16  into the first location  18   a.  At this point, the optical reader  26  reads a second set of information from the second tray  16 . This allows the system to index and determine what the appropriate control loop is required for processing the components in the second stackable tray. In this way, the system  10  can simultaneously have a plurality of instruction sets and, therefore, welding processes running for various trays  16 .  
         [0017]     Reference is now made to  FIG. 2  which represents a flow chart describing the functioning of the present invention. The system  10  begins at process block  34  where a first stackable tray  16  containing at least one work piece  14  is loaded onto the conveyor  12 . At this point, the conveyor  12  is indexed, bringing the stackable tray  16  into position where the optical reader  26  can read the optical information off of the optical tag  24 . In process block  36 , the system  10  uses the optical reader  26  to read the optical information off of the tray. In process block  38 , the system now determines which control loop or loops are appropriate for the processing of the components  14  within the tray  16 . These control loops are a set of instructions for controlling the flow of the stackable containers within the system  10 , and more particularly the flow of components through system  10 . Additionally found within the control loop as are sets of instructions for the one or more robotic arms  32  as well as for one or more stud welders  20  within the system  10 . Upon initiation of the control loop, the tray  16  is indexed to the required work station  18 .  
         [0018]     At the first work station  18 , the robot  22  of the work station  18  begins to remove individual components  14  from the stackable tray  16  and bring the components to the first weld stud machine  20 . A first sized weld stud is coupled to an exterior surface of the work piece  14 . At this point, the work piece  14  is optionally shifted with respect to the weld stud machine  20  to fasten a second stud to an exterior surface of the work piece. This process is repeated until all of the weld studs for a particular work piece  14  which are to be fastened by the first weld stud machine  20  have been coupled. The robot  22  then returns the work piece  14  to the stackable tray in an orientation which may be different that the original orientation of the component. The system  10  will recursively repeat the above steps for the number of components which must be processed in the first work station.  
         [0019]     In process block  40  the system  10  actuates the conveyor  12  so as to position the stackable tray  16  at the second work station  18   b.  At the second work station  18   b,  the robot  22   b  of the work station  18   b  begins to again remove individual components  14  from the stackable tray  16  and bring the components  14  to a second weld stud machine  20 . A second sized weld stud is coupled to an exterior surface of the work piece  14 . At this point, the work piece  14  is optionally shifted with respect to the weld stud machine  20  to fasten a second stud to an exterior surface of the work piece  14 . This process is repeated until all of the weld studs for a particular work piece  14  which are to be fastened by the second weld stud machine  20   b  have been coupled.  
         [0020]     The robotic arm  32  then returns the work piece  14  to the stackable tray  16  in an orientation which may be different that the original orientation of the component within the tray  16 . The system  10  will recursively repeat the above steps for the number of components which must be processed in the first work station.  
         [0021]     In process block  42 , a second stackable tray  16  containing at least one work piece  14  is loaded onto the conveyor  12 . At this point, the conveyor  12  is indexed, bringing the second stackable tray  16  into position where the optical reader  26  can read the optical information off of the tray. In process block  44 , the system  10  uses an optical reader  26  to read the optical information off of the tray. In process block  46 , the system  10  now determines which control loop or loops are appropriate for the processing of the components within the tray. Upon initiation of the control loop, the tray is indexed to the required first work station.  
         [0022]     At the first work station  18   a,  the robot  22  of the work station begins to remove individual components  14  from the second stackable tray  16  and bring the components  14  to the first weld stud machine  20  for the second tray  16 . A first sized weld stud is coupled to an exterior surface of the work piece  14 . At this point, the work piece  14  is optionally shifted with respect to the weld stud machine  20  to fasten a second stud to an exterior surface of the work piece  16 . As previously described, the process is repeated until all of the weld studs for a particular work piece which are to be fastened by the first weld stud machine for the second tray  16  have been coupled. The robotic arm  32  then returns the work piece  14  to the stackable tray  16  in an orientation which may be different that the original orientation of the component. The system  10  will recursively repeat the above steps for the number of components which must be processed in the first work station  18   a.

Technology Category: 4