Abstract:
A multi-architecture flexible assembly structure includes transfer devices, and programmable loading structures, work fixtures, and unloading structures for assembling components into selected different styles of finished assemblies.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates to an assembly structure and more particularly to a multi-architecture flexible assembly structure including programmable conveying devices, programmable fixture devices, and programmable welding devices.  
       BACKGROUND OF THE INVENTION  
       [0002]     In the current vehicle market, there exists a variety of body shapes, sizes, styles, and configurations to meet consumer demand. Typically, manufacturing facilities are limited in the types of vehicles which may be manufactured due to different vehicle configurations for different vehicle types. Compact cars and luxury cars, for example, require substantially different body panel sizes, shapes, and in some cases require different quantities of body panels.  
         [0003]     A vehicle manufacturing facility typically includes a tooling system that has been mechanically and electrically designed to produce variations of a single vehicle architecture. Changeover to a different body architecture requires that the tooling system be reconfigured, reprogrammed, and in some cases completely replaced, resulting in substantial changeover delays and long startup times. A current trend has been to attempt to reduce the changeover times and provide for increased flexibility in manufacturing facilities such that multiple vehicle body architectures may be produced in a single vehicle manufacturing facility.  
         [0004]     It would be desirable to develop a multi-architecture flexible assembly structure wherein flexibility, efficiency, and capital equipment utilization are maximized and tooling changes and switchover downtime are minimized.  
       SUMMARY OF THE INVENTION  
       [0005]     Consistent and consonant with the present invention, a multi-architecture flexible assembly structure wherein flexibility, efficiency, and capital equipment utilization are maximized and tooling changes and switchover downtime are minimized, has surprisingly been discovered.  
         [0006]     The multi-architecture flexible assembly structure comprises: a first station having a loading structure to load components to the first station; a second station having at least one work fixture to convert the components into a finished assembly; a third station having an unloading structure to unload the finished assembly from the third station; a first transfer device to transfer the components from the first station to the second station; and a second transfer device to transfer the finished assembly from the second station to the third station, wherein the loading structure, the at least one work fixture, the first transfer device, and the second transfer device are programmable to facilitate production of at least two distinct finished assemblies using the same loading structure, the at least one work fixture, the first transfer device, and the second transfer device. In the following description, the components are sheet metal panels and the finished assemblies are used in vehicles. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which:  
         [0008]      FIG. 1  is a schematic perspective view of a multi-architecture flexible assembly structure in accordance with the present invention and showing a tool base in a first position;  
         [0009]      FIG. 2  is a schematic perspective view of the multi-architecture flexible assembly structure of  FIG. 1  showing the tool base in a second position;  
         [0010]      FIG. 3  is a schematic perspective view of a second embodiment of the present invention illustrating a multi-architecture flexible assembly structure and showing a tool base in a first position;  
         [0011]      FIG. 4  is a schematic perspective view of the multi-architecture flexible assembly structure of  FIG. 3  showing the tool base in a second position; and  
         [0012]      FIG. 5  is a schematic perspective view of an alternative embodiment of a third station of a multi-architecture flexible assembly structure in accordance with the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]     Referring now to  FIG. 1 , there is shown generally at  10  a schematic perspective view of a multi-architecture flexible assembly structure in accordance with the present invention. The multi-architecture flexible assembly  10  has a first station  12 , a second station  14 , and a third station  16  aligned in a direction of movement indicated by an arrow  17 .  
         [0014]     The first station or loading station  12  has a first linearly indexable transfer device or tool base  18  driven by a linear drive  20 . A plurality of programmable flexible locating and clamping units  22  is mounted on the first tool base  18 . An example of one type of programmable locating and clamping unit  22  is shown and described in assignee&#39;s commonly owned U.S. patent application Ser. No. 09/738,399, the contents of which are hereby incorporated by reference. The first station  12  also includes a plurality of floor mounted material handling robots or loading structures  24 . The robots  24  load components  26 , such as sheet metal panels, as desired to the flexible locating and clamping units  22  on the first tool base  18 . Additional manufacturing processes may be located prior to the first station  12  as desired to pre-assemble or otherwise prepare the components  26  to be received by the first station  12 . Work fixtures, as herein described, may be positioned at the first station  12  as desired to conduct work processes on the components  26  at the first station  12 . The base  18  is supported by a support surface  27  such as a building floor or a platform.  
         [0015]     A second linearly indexable transfer device or tool base  28  is linked to the first tool base  18 , and is driven by the same linear drive  20  for simultaneous movement. The bases  18  and  28  can be integral, as shown, or separate and are movable together in the direction  17  on a pair of rails  29  attached to the support surface  27 . A plurality of rest fixtures  30  mounted on the base  28  is provided to support and transfer a finished product  32  such as a vehicle assembly shown in the third station  16 . The rest fixtures  30  may also include a lifting fixture or apparatus (not shown) for lifting and holding the assembly  32  stationary when the first tool base  18  and the second tool base  28  are indexed during the production cycle, discussed in more detail below. The second tool base  28  is positioned in the second station  14  when the first tool base  18  is positioned in the first station  12 . When the first tool base  18  is positioned in the second station  14 , the second tool base  28  will be positioned in the third station  16 , as shown in  FIG. 2 . It is understood that the first tool base  18  and the second tool base  28  could be used in a non-linked format and indexed separately without departing from the scope and spirit of the invention.  
         [0016]     The second station or assembly station  14  has work fixtures including, for example, a plurality of floor mounted welding robots  34 , an overhead pogo weld robot  36  mounted on a beam  37 , an overhead material handling robot  38  mounted on a beam  39 , and a plurality of programmable flexible manipulators  40 . Lower electrodes  42  for the pogo weld robot  36  are mounted on the programmable flexible manipulators  40 . Examples of the pogo weld robot  36  are shown and described in assignee&#39;s commonly owned U.S. Pat. Nos. 6,621,036 and 6,429,397, the contents of which are hereby incorporated by reference. Other work fixture types may be used as desired. A slot  43  is formed in the bases  18  and  28  to receive the manipulators  40  that are fixedly mounted on the support surface  27 .  
         [0017]     In the embodiment shown, the third station  16  is an unload station. It is understood that additional stations having tooling and/or assembly operations can be added prior to, on, or after the third station  16  as desired without departing from the scope and spirit of the invention. The second tool base  28  is positioned in the third station  16  (see  FIG. 2 ) during an unloading operation where the vehicle assembly  32  is removed from the second tool base  28  and transferred for shipping or to another processing station. An unloading structure or a transfer structure  44  is provided at the third station  16 .  
         [0018]     In operation, at the start of a production cycle, the first tool base  18  is positioned in the first station  12 , and the second tool base  28  is positioned in the second station  14 . An appropriate program is loaded in each of the respective controllers for the programmable locating and clamping units  22 , the floor mounted welding robots  34 , the overhead mounted pogo weld robot  36 , the overhead fixed mounted material handling robot  38 , and the programmable flexible manipulators  40  for a particular body style of the vehicle assembly  32 . Responsive to the program, the programmable locating and clamping units  22  are automatically positioned in locations corresponding to desired locating and clamping positions of the incoming components  26 . The components  26  are loaded to the programmable locating and clamping units  22  by the robots  24 , or can be manually loaded.  
         [0019]     Once the load cycle is complete, the first tool base  18  is caused to move linearly on the rails  29  to the second station  14 , as illustrated in  FIG. 2 . The components  26  are securely held by the programmable locating and clamping units  22  during the transfer operation. When the first tool base  18  is positioned at the second station  14 , the floor mounted welding robots  34  and the overhead pogo welding robot  36  in conjunction with the flexible manipulators  40  perform welding on the components  26  to create the vehicle assembly  32 . After the first weld cycle is complete, the vehicle assembly  32  is unclamped and the overhead fixed mounted material handling robot  38  removes the vehicle assembly  32  from the first tool base  18 .  
         [0020]     To begin the next cycle, the empty first tool base  18  and the empty second tool base  28  are caused to return to the first station  12  and the second station  14 , respectively. Upon the return of the first tool base  18  to the first station  12 , the next loading cycle as described above commences. At the second station  14 , the floor mounted welding robots  34  can perform additional spot welds while the assembly  32  is held by the fixed mounted material handling robot  38 . Once the second weld cycle in the second station  14  is complete, which typically coincides with the conclusion of the next load cycle in the first station  12 , the fixed mounted material handling robot  38  deposits the completed vehicle assembly  32  on the second tool base  28 . The first tool base  18  and the second tool base  28  are caused to index, moving the components  26  on the first tool base  18  to the second station  14 , and the vehicle assembly  32  on the second tool base  28  to the third station  16  ( FIG. 2 ). The transfer structure  44  unloads the vehicle assembly  32  from the third station  16  and transfers the vehicle assembly  32  to a separate conveyance system for subsequent assembly processes. The cycle then repeats as described above.  
         [0021]     In  FIG. 3 , there is shown generally at  50  a schematic perspective view of a second embodiment of a multi-architecture flexible assembly structure in accordance with the present invention. Like structures from  FIGS. 1 and 2  are shown in  FIGS. 3 and 4  with the same reference numerals for clarity. The multi-architecture flexible assembly  50  has the first station  12 , the second station  14 , and the third station  16 .  
         [0022]     The first station or loading station  12  of the second embodiment includes the first linearly indexable transfer device or tool base  18  driven by the linear drive  20 . The programmable flexible locating and clamping units  22  are mounted on the first tool base  18 . The first station  12  also includes the material handling robots or loading structures  24 . The robots  24  load the components  26  as required to the flexible locating and clamping units  22  on the first tool base  18 .  
         [0023]     The second station or assembly station  14  has work fixtures including, for example, the floor mounted welding robots  34 , the overhead mounted pogo weld robot  36 , and the programmable flexible manipulators  40 . The lower electrodes  42  for the pogo weld robot  36  are mounted on the programmable flexible manipulators  40 . The second station  14  also includes a second transfer device or rail-mounted robot  52  which replaces the fixed mounted material handling robot  38  of the first embodiment. The rail-mounted robot  52  is capable of being indexed linearly from the second station  14  to the third station  16  along a rail  54  parallel to the direction arrow  17 . Other work fixtures may be used as desired.  
         [0024]     The third station  16  is an unload station. It is understood that additional stations having tooling operations can be added as desired and that additional fixtures, including work fixtures, may be added to the third station  16  without departing from the scope and spirit of the invention. A plurality of holding fixtures  56  is provided on a base  57  to support the finished vehicle assembly  32 . The unloading structure or transfer structure  44  is provided at the third station  16 .  
         [0025]     In operation, at the start of the production cycle, the first tool base  18  is positioned in the first station  12 . An appropriate program is loaded in each of the respective controllers for the programmable locating and clamping units  22 , the floor mounted welding robots  34 , the overhead mounted pogo weld robot  36 , the rail-mounted robot  52 , and the programmable flexible manipulators  40  for a particular body style of the vehicle assembly  32 . Responsive to the program, the programmable locating and clamping units  22  are automatically positioned in locations corresponding to desired locating and clamping positions of the incoming components  26 . The components  26  are loaded to the programmable locating and clamping units  22  by the robots  24 , or can be manually loaded.  
         [0026]     Once the load cycle is complete, the first tool base  18  is caused to move linearly to the second station  14 , as illustrated in  FIG. 4 . The components  26  are securely held by the programmable locating and clamping units  22  during the transfer operation. When the first tool base  18  is positioned at the second station  14 , the floor mounted welding robots  34  and the overhead pogo welding robot  36  in conjunction with the flexible manipulators  40  perform welding on components  26  to create the vehicle assembly  32 . After the first weld cycle is complete, the rail mounted robot  52  clamps onto the vehicle assembly  32  which is then unclamped from the flexible locating and clamping units  22  of the first tool base  18 .  
         [0027]     To begin the next cycle, the empty first tool base  18  is returned to the first station  12 . Upon the return of the first tool base  18  to the first station  12 , the next loading cycle as described above commences. At the second station  14 , the floor mounted welding robots  34  can perform additional spot welds while the vehicle assembly  32  is held by the rail-mounted robots  52 . Once the second weld cycle in the second station  14  is complete, which coincides with the conclusion of the next load cycle in the first station  12 , the rail-mounted robot  52  indexes to the third station  16  and deposits the vehicle assembly  32  on the holding fixtures  56 . Simultaneously, the first tool base  18  is caused to index, moving the components  26  on the first tool base  18  to the second station  14 . The transfer structure  44  unloads the vehicle assembly  32  from the holding fixtures  56  of the third station  16  and transfers the vehicle assembly  32  to a separate conveyance system for subsequent assembly processes. The rail-mounted robot  52  and the first tool base  18  return to second station  14  and the first station  12 , respectively. The cycle then repeats as described above.  
         [0028]     As shown and described, the flexible assembly structures  10 ,  50  can accommodate a wide variety of dissimilar styles and platforms of vehicle architectures. The various vehicle styles and architectures are accommodated through software programming of the flexible locating and clamping units  22 , the flexible manipulators  40  used with the pogo welder  36 , and the robots  24 ,  52 . While the components  26  and the assembly  32  were described above in terms of assembling vehicles, the flexible assembly structures  10 ,  50  can be used assemble other types of products.  
         [0029]     An alternative embodiment of the third station is indicated generally at  16   a  in  FIG. 5 . The third station  16   a  is an unloading and re-spotting station that includes a plurality of welding robots  58 . The robots  58  may be one or any of the floor mounted welding robot  34 , the pogo welding robot  36 , and the programmable flexible manipulator  40  as shown in  FIGS. 1-4 . The welding robots  58 , though shown as mounted on pedestals  59 , may be floor-mounted, rail-mounted, or the like. The third station  16   a  also includes at least one material handling robot  60 . The material handling robot  60  may be one or any of the material handling robots  24 , the fixed mounted material handling robot  38  of  FIGS. 1-2  and the rail-mounted robot  52  of  FIGS. 3-4 . The third station  16   a  receives a workpiece, such as the assembly  32 , from the second station  14 , where the assembly  32  is held in place by the material handling robot  60 . At the third station  16   a , the welding robots  58  can perform additional spot welds while the assembly  32  is held in place in the second tool base  28  by the material handling robot  60 . After the additional spot welds are performed by the welding robots  58 , the material handling robot  60  is operable to move the assembly  32 , for transfer for shipping or to another processing station.  
         [0030]     From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions.