Abstract:
A vehicle body assembly and sequencing system includes the advantages of a batch vehicle body build sequence with the advantages of a random sequence of vehicle body styles transferred to a painting area. The build system includes using automated guided vehicles which transfer and store assembled, un-painted vehicle bodies in a storage area and sequentially transfers selected bodies from the storage area to the painting area achieving a random or variable supply of different vehicle bodies to be painted a certain color.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application Ser. No. 61/169,553, filed Apr. 15, 2009, which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The invention generally relates to the field of vehicle body assembly, transfer and logistical sequencing prior to exterior painting of the vehicle body. 
     BACKGROUND 
     The structural skeleton of a vehicle, typically made from welded sheet metal components, is generally referred to in the industry as a body-in-white (BIW), due to the sheet metal being initially coated in a rust retardant coating which is often white in color, prior to being painted the exterior color of the vehicle. It is also common in the industry for vehicle assembly plants to have flexible assembly lines which are capable of relatively quick changes to build different body style of vehicles to support production needs. 
     Multiple models of vehicle BIWs can be assembled in a “batch mix” or a “random mix”. In a batch assembly mix, all BIWs of a first type of vehicle model are assembled, then all BIWs of a second type of vehicle model are assembled, and so on. Assembling multiple models of vehicles in a batch mix can be advantageous because the number of tooling changes can be kept low, as a tooling change only needs to be undertaken when switching between assembling different models of vehicles. As an example, if there are seven different models of vehicles in a batch mix, six tooling changes are necessary to assemble all the vehicles in the batch mix assuming the tooling is initially set up for a first of the seven models. 
     In a random vehicle body assembling mix, the order in which BIWs for various models of vehicles are assembled is based on the color that the BIWs are to be painted. For example, a build that includes three different types of vehicle models, each of which includes vehicles of two colors, red and blue. In this example, bodies-in-white of a first type of vehicle model to be painted red are assembled, then bodies-in-white of a second type of vehicle model to be painted red are assembled, then bodies-in-white of a third-type of vehicle to be painted red are assembled. Next, a paint change is undertaken to change the color of paint to be applied from red to blue. After the paint change, bodies-in-white of the first type of vehicle model to be painted blue are assembled, then bodies-in-white of the second type of vehicle model to be painted blue are assembled, then bodies-in-white of the third-type of vehicle to be painted blue are assembled. Assembling different models of vehicle in a random mix can be advantageous because the number of paint changes can be kept low, as the number of paint changes can be one fewer than the total number of colors assuming the paint is initially set up for a first color. 
     Painting vehicles assembled in a batch build or assembly mix can be problematic because all bodies-in-white of a certain type of vehicle model are not typically painted the same color. One solution to this problem is to paint the bodies-in-white in the order in which they are assembled and to change the color of paint as necessary. However, this solution requires a large number of paint changes, and paint changes are time consuming and expensive. 
     Further, assembling vehicles in a random mix can be problematic because a large number of tooling changes are typically required. For example, the number of tool changes increases as the number of paint colors increases. The number of tooling changes required for a random mix is approximately equal to the total number of colors multiplied by the number of vehicle models. 
     SUMMARY 
     Examples of a vehicle body assembly and sequencing system as described herein can include assembling vehicle bodies-in-white (BIWs) in a batch mix, storing the assembled BIWs, and removing the assembled BIWs from storage in an order based on the color that the bodies-in-white are to be painted. 
     In one example of the vehicle body assembly and sequencing system, vehicle BIWs can be assembled along one or more assembly lines in a batch mix, with all models of a first type of vehicle body assembled in one batch, all models of a second type assembled in another batch, and so on. Each assembled BIW can be transferred from an end of its assembly line to a storage rack by an automated guided vehicle (AGV). The BIWs can be organized in the storage rack by, for example, model type or color to be painted. Another AGV can selectively remove BIWs from the storage rack and transfer them to a painting area where the BIWs are to be painted the desired exterior color. Preferably, the BIWs are selectively removed from the storage rack based on the color that they are to be painted to achieve the desired “random mix” to paint. That is, all bodies-in-white to be painted a first color, regardless of body style, can be removed from the storage rack and transferred to the painting area, following by all bodies-in-white to be painted a second color, and so on. 
     The present system offers numerous and significant advantages over prior systems which typically required random build mixes in order to achieve the desired random mix of body styles to paint so as to minimize paint color changes. Although advantageous on the painting side, the random build or assembly mix required was difficult, time consuming and expensive. The present system provides for the desired random vehicle body styles to paint, but permits the desired batch build which greatly reduces complexity, coordination, time and money on the build process side. Through use of the present system, sequencing and storage of the BIWs, quality build and paint processes are achieved while maintaining quality and integrity of the BIWs which serves as the foundation for the entire vehicle. 
    
    
     
       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 plan view of an example of a manufacturing facility including various body-in-white assembly lines, a body-in-white storage area, and a vehicle body painting area; 
         FIG. 2  is a schematic chart of an example of a prior art random build mix and chart of the built vehicle body sequence to the painting area; 
         FIG. 3  is a schematic chart of an example of the present invention batch vehicle build sequence, an exemplary storage sequence and built vehicle body sequence from the storage area to the painting area; 
         FIG. 4  is a perspective view of an example of a vehicle body pallet; 
         FIG. 5  is a perspective view of the pallet of  FIG. 4  carrying an example of a vehicle body-in-white; 
         FIG. 6  is a rear elevation view of the pallet and vehicle body-in-white of  FIG. 5 ; 
         FIG. 7  is a side elevation view of an example of an automated guided vehicle (AGV) usable with an example of a vehicle body storage rack; 
         FIG. 8  is a perspective view of the pallet of  FIG. 5  being carried by the AGV of  FIG. 7 ; 
         FIG. 9  is a perspective view of an example of a vehicle body storage rack including four columns and two rows of storage compartments; 
         FIG. 10  is a plan view of five exemplary storage racks, each rack positioned in a storage bay, for storing 330 vehicle bodies awaiting painting; 
         FIG. 11  is an enlarged plan view of one of the storage racks in  FIG. 10 ; and 
         FIG. 12  is a schematic flow chart of an exemplary build and storage sequence of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Examples of a vehicle body assembly and sequencing system are discussed herein with reference to  FIGS. 1-12 . As shown in  FIG. 1 , an example of a manufacturing facility  10  can include various assembly lines  12  for at least partially assembling, for example, vehicle bodies-in-white (BIWs)  14 , which are generally shown in  FIGS. 5 and 6 . The manufacturing facility  10  can also include a vehicle body storage area  16 , automated guided vehicle (AGV) storage and coordination area  17  and a vehicle body painting area  18 . 
     Each assembly line  12  can include work stations connected by a track (not shown) along which the BIWs  14  can be moved and sequenced through the various build and assembly operations. Automated robots or workers at each work station can perform operations, such as welding, clamping, gluing and/or bolting operations, on the BIWs  14  or parts which eventually form the BIWs  14 . Each BIW  14  can be supported and carried on a pallet  20  shown in  FIG. 4  while being moved along the assembly line  12 . Alternately, each BIW  14  can be positioned on the pallet  20  at the end of one of the assembly lines  12  by, for example, an automated robot. 
     Tool changes can be performed such that the assembly lines  12  can assemble different vehicle body style models of BIWs  14 , such as a first model, a second model, and a third model of BIW  14 . Each tool change can involve changing end effectors, for example a clamp, weld gun etc., on automated robots, repositioning automated robots, and/or other tool alterations. In a preferred example generally shown in  FIG. 3 , the assembly lines  12  assemble the BIWs  14  in a batch mix, assembling all models of the first type (A) in one batch, all models of the second type (B) in a subsequent batch, and so on. Tool changes can be performed between assembling different batches of vehicles, if necessary. For example, a first tool change can be performed between assembling batches of the first and second models of BIWs  14 , and a second tool change can be performed between assembling batches of the second and third models of BIWs  14 . 
     As shown in  FIG. 2 , a typical random build sequence and sequence of vehicle bodies to paint is shown. In the first column, an example of 24 vehicles (numbered 1-24) are scheduled to be assembled along assembly lines  12 . A total of 4 different vehicle body styles are needed (A, B, C and D). In order to achieve the desired body style and number of vehicles going to be painted a certain color, it was predetermined before the build what body styles were going to be painted a certain color and how many of that body style, for example as shown in the second column of  FIG. 3 . Under typical prior art build and sequencing processes, a “random” vehicle body build was established so the proper body style and numbers of vehicles would be sent to paint. In other words, the less desirable “random” build sequence, requiring complex organization and many tooling changes, was used to achieve the desirable body style mix to paint. 
     As shown in  FIG. 3 , the present invention allows for the desired body style mix to paint (shown in the second column, which is the same as the mix to paint in  FIG. 2 ), but uses the desirable “batch” body build sequence and selected storage areas (A, B, C and D) (shown in the second column of  FIG. 3 ) between assembly and before the vehicles are sent to paint, to achieve the desired process both on the assembly and paint process areas. A further explanation of the present system is explained and illustrated below. 
     Referring now to  FIGS. 4-6 , an exemplary vehicle support pallet  20  can include a pair of parallel, spaced apart longitudinal rails  22  positioned along a longitudinal axis  23 . One or more transverse beams  24  extending between and welded, bolted or otherwise attached to the longitudinal rails  22 . One or more support structures  26  can be disposed longitudinally inward from the longitudinal ends of the pallet  20 , and each support structure  26  can extend transversely between the longitudinal rails  22 . Each support structure  26  can include a transverse rail  28  welded, bolted or otherwise attached to the longitudinal rails  22 , and each support structure  26  can also include a pair of vertical beams  30  welded, bolted or otherwise attached to and extending orthogonally from its transverse rail  28 . Distal ends of the vertical beams  30  can include respective locating pins  32  for insertion into apertures in the BIW  14  to locate and support the BIW  14  relative to the pallet  20  as shown in  FIGS. 5 and 6 . A longitudinal beam  34  can extend parallel to the longitudinal rails  22  at a location between the rails  22  in the transverse direction, and the longitudinal beam  34  can be welded, bolted, or otherwise attached to one or more of the transverse beams  24  and the support structures  26 . The longitudinal beam  34  can include a guide flange  36  extending orthogonally from the longitudinal beam  34 , and the guide flange  36  can be used to engage, as an example, the track along one of the assembly lines  12  for guiding the pallet  20  and BIW  14  along the assembly line  12 . 
     As shown in  FIGS. 4 and 8 , a pad  38 , which can be made of rubber or another flexible material, can be disposed over the longitudinal end of each longitudinal rail  22 . The pad  38  can offer protection as a result of contact between the pallet  20  and another structure by at least partially absorbing an impact. As best seen in  FIG. 8 , the pallet  20  can include blocks  37  defining respective apertures  39 , with two blocks  37  being positioned along each longitudinal rail  22  and the aperture openings oriented generally transverse to longitudinal axis  23 . The blocks  37  on one of the rails  22  can be aligned with the blocks  37  on the other rail  22  in the transverse direction. 
     An example of an automated guided vehicle (AGV)  40  as shown in  FIG. 7  can include a lift mechanism  42  having a pronged fork  44 , which is shown in three positions along the lift mechanism  42  in  FIG. 7  to illustrate the vertical movement capability of the pronged fork  44  along an axis  43 . The lift mechanism  42  can be telescoping and can be pneumatically actuated, chain-driven, or otherwise actuated. The AGV  40  can include one or more motors for driving the AGV  40  and actuating the lift mechanism  42 , a controller (e.g., a CPU and memory having software stored thereon) for providing instructions to the motor, and one or more batteries or another power source for powering the one or more motors, the controller, and/or other components of the AGV  40 . The AGV  40  can include a wireless network card for wirelessly receiving operating instructions. Alternatively, operating instructions can be programmed into the AGV  40  via, as examples, a port on the AGV  40  for connecting to a programming device, or an interface on the AGV  40 . The AGV  40  can be moveable about the manufacturing facility  10  along a path programmed into the controller or determined by the controller (e.g., as a result of input from sensors included on the AGV  40  and/or at various location in the manufacturing facility  10 ). The path can extend, for example, from a first position or pick-up point at the end of one of the assembly lines  12  and end at a second or drop off point at the vehicle body storage area  16 , or alternately from the vehicle body storage area  16  to the vehicle body painting area  18 . The controller can instruct the AGV  40  to actuate the lift mechanism  42  to move the fork  44  vertically at certain occasions along the path. Other means for programming, communicating and/or controlling the AGV known by those skilled in the art may be used. 
     As shown in  FIG. 8 , the AGV  40  can move such that prongs  44   a  and  44   b  of its fork  44  extend through the apertures  39  defined by the blocks  37  on the pallet  20 . That is, the AGV  40  can adjust the position of its fork  44  such that the prongs  44   a  and  44   b  are aligned vertically with the apertures  39  defined by the pallet  20 , and then the AGV  40  can move in a direction transverse of the pallet  20  axis  23  such that the prongs  44   a  and  44   b  are inserted through respective apertures  39 . The AGV  40  can actuate the lift mechanism  42  to raise the fork  44 , causing the prongs  44   a  and  44   b  to engage the blocks  39 , thereby lifting the pallet  20  and, if mounted on the pallet  20 , the BIW  14 . These movements can take place, as examples, to pick up the pallet  20  at the end of one of the assembly lines  12 , or to pick up the pallet  20  from the vehicle body storage area  16 . The AGV  40  can then transport the pallet  20  and BIW  14  from the assembly line  12  to the storage area  16  or from the storage area  16  to the painting area  18  by moving along one of the exemplary paths described above. To remove the pallet  20  from the AGV  40 , the AGV  40  can lower the fork  44  such that the pallet  20  is supported on by an object other than the fork  44 , and then the AGV  40  can move in the direction transverse to the pallet  20  such that the fork  44  is removed from the blocks  39  of the pallet  20 . 
     Referring to  FIGS. 9-11 , the vehicle body storage area  16  can include one or more storage racks  60 , which are suitable for use in a bay  61  in a typical assembly plant. An example of a storage rack  60  is shown in  FIG. 9 . The storage rack  60  defines multiple compartments  62 . Each compartment  62  is sized and oriented to preferably receive a single pallet  20  carrying a BIWs  14 . The storage compartments  62  can be arranged side-by-side, end-to-end, and stacked on top of one another such that the frame  60  defines a three dimensional array of compartments  62 . The rack  60  as shown in  FIG. 9  is two rows of compartments  62  wide, two columns  90  along axis  69  of compartments  62  deep, and three compartments  62  high, thus defining a total of twelve compartments  62 . In an alternate example shown in  FIG. 11 , a rack  60 ′ includes two rows of compartments  62  wide, eleven columns of compartments  62  deep, and three compartments  62  high, for a total of sixty-six compartments  62  per storage rack  60 ′. As shown in  FIG. 10 , multiple racks  60 ′ in multiple bays  61  can be included in the storage area  16 , with five racks  60 ′ providing for storage of 330 vehicle bodies in compartments  62  in the aggregate. Alternatively, the rack  60  can define a different sized and oriented array of compartments  62  known by those skilled in the field. 
     Referring back to  FIG. 9 , the exemplary rack  60  can include vertical beams  64  extending from a floor to a top of the rack  60 , with one of the vertical beams  64  being positioned at each corner of a stack of compartments  62 . While not shown, the vertical beams  64  can include support bases at their bottom ends, such as planar sheets or other structures offering a wider base for additional support. Connecting beams  66  can extend between the top ends of the vertical beams  64 , and the connecting beams  66  can be welded, bolted, or otherwise attached to the vertical beams  64 . The connecting beams  66  can enhance the stability of the vertical beams  64 . Each compartment  62  can include a pair of cantilevers  68  at opposing ends of the compartment  62 . The cantilevers  68  can extend toward one another from the vertical beams  64  at the ends of the bay  62 . The cantilevers  68  can be spaced apart in a direction from one end of the compartment  62  to the other by a distance sufficient for the AGV  40  to pass therebetween, which can allow the AGV  40  to travel along axis  69  and pass from one side of the rack  62  to the other side. 
     Each cantilever  68  can include a flange  70  angled relative the vertical. The flange  70  can provide a surface for the pallet  20  to slide down if the pallet  20  is deposited by the AGV  40  at a position vertically aligned with the flange  70 . The space between lower edges of the flanges  70  on the cantilevers  68  at opposing ends of the bay  62  can be equal to the length of the pallet  20 , thereby allowing the flanges  70  to center the pallet  20  in the compartment  62 . 
     In one example of operation as schematically shown in  FIG. 12 , during a preferred “batch” vehicle body build process  100 , an AGV  40  can pick up the BIW  14  from the assembly line  12  as described above, and at step  120  transport the BIW  14  to the storage area  16 , and deposit the BIW  14  on the storage rack  60  in a selected compartment  62  in step  140 . The method of organization or position at which the AGV  40  deposits the BIW  14  on the storage rack  60  is preferably be based on the model style in step  125  or by color to be painted  130  to suit the particular application, plant process, performance specification or other factors known by those skilled in the art. In step  160 , the BIWs are selectively engaged, for example by an AGV, removed from the storage rack  60  and bay  61  and transferred to the painting area  18  to achieve the desired random mix of vehicle bodies to paint. 
     As generally illustrated in  FIGS. 9 and 10 , since the AGV  40  can pass along axis  69  between the cantilevers  68  of the storage rack  60  in the direction from side-to-side of the compartments  62 , the AGV  40  can travel to a furthest available column of compartments  62  in order to deposit the pallet  20  and BIW  14  in one of the compartments  62  in that column. The AGV  40  can then pickup another pallet  20  and BIW  14 , and deposit that pallet  20  and BIW  14  in the same column of compartments  62 , and the AGV  40  can repeat this procedure until that column of compartments  62  is full. Once that column of compartments  62  is full, the AGV  40  can deposit pallets  20  and BIWs  14  in the next furthest available column of compartments  62 . By depositing pallets  20  and BIWs  14  in the furthest available column of compartments  62 , the AGV  40  can avoid depositing pallets  20  and BIWs  14  at locations that would block its access to other compartments  62 . 
     Also, the first pallet  20  and BIW  14  of a new group of pallets  20  and BIWs  14  (e.g., BIWs  14  of a new model or to be painted a new color) can be deposited at a furthest side of the frame  60  from where the depositing AGV  40  entered the frame  60  such that the pallet  20  and BIW  14  of the new group is accessible from an opposing side of the frame  60  from which the depositing AGV  40  entered the frame  60 . For example, as shown in  FIG. 10 , AGVs  40  can enter the frame  60 ′ from side  72  and can deposit pallets  20  and BIWs  14  as close as possible to opposing side  74 . AGVs  40  can then remove pallets  20  and BIWs  14  from side  74 . As a result, each group of BIWs  14  can be accessible for removal from the frame  60  if opposing sides of the frame  60  are used for depositing and removing pallets  20  and BIWs  14 . 
     The vehicle body painting area  18  can include automated robots, workers, or other devices equipped to paint the BIWs  14 . As mentioned earlier and as shown in  FIG. 10 , AGVs  40  can remove pallets  20  and BIWs  14  from the opposing side  74  of the frame  60 ′ from the side  72  via which the pallets  20  and BIWs  14  are deposited. Removed pallets  20  and BIWs  14  can be transported by AGVs  40  to the painting area, and the BIWs  14  can be painted. 
     As mentioned, in an alternate example, the BIWs  14  can be stored and removed from the frame  60  in an order based on the color that the BIWs  14  are to be painted. For example, all BIWs  14  of a first model type to be painted a first color can be removed from the frame  60  and transported to the painting area  18 , followed by all BIWs  14  of a second model type to be painted the first color, then all BIWs  14  of a third model type to be painted the first color, and so on. Next, the painting equipment at the painting area  18  can be reconfigured to supply a second color of paint. All BIWs  14  of the first model type to be painted the second color of paint can be removed from the frame  60  and transported to the painting area  18 , followed by all BIWs  14  of the second model type to be painted the second color, then all BIWs  14  of the third model type to be painted the second color, and so on. The painting equipment at the painting area can be reconfigured a second time, if necessary, to supply a third color, and the process can continue. 
     The above-described examples have been described in order to allow easy understanding of the invention and do not limit the invention. On the contrary, the invention is intended to cover various modifications and equivalent arrangements, whose scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structure as is permitted under the law.