Abstract:
Methods for welding motor vehicle body component subassemblies at a weld stations are disclosed. First and second pallets may be arranged for reciprocal movement between a load/unload station and the weld station and the pallets are alternately moved from a load/unload station to the weld station while the other pallet is moved from the weld station to a load/unload station. Each pallet may have a plurality of substations for receipt of component subassemblies and, while each pallet is at the load/unload station, the component subassembly at each substation is moved to the next successive substation and a further component is added to the moved component.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present divisional application claims the benefit of U.S. Provisional Application Ser. No. 61/052,764 filed May 13, 2008 and U.S. patent application Ser. No. 12/269,955 filed Nov. 13, 2008, both of which are incorporated herein by reference in their entirety. 
     
    
     BACKGROUND OF THE DISCLOSURE 
       [0002]    This invention relates to motor vehicle manufacturing and more particularly to a high density welding processes to facilitate manufacture of subassembly components of motor vehicle bodies. 
         [0003]    In the mass production of motor vehicles on an assembly line basis, it is imperative that the various subassembly components come together for the final assembly process in an efficient and orderly manner. The current subassembly procedures, while generally satisfactory, tend to be manpower-intensive, tend to require large amounts of factory floor space, sometimes present maintenance complications, require excessive capital expenditures, and may present safety and/or environmental concerns. 
       SUMMARY OF THE DISCLOSURE 
       [0004]    The present invention is directed to the provision of an improved high density welding subassembly machine for motor vehicle applications. 
         [0005]    More specifically, the present invention is directed to a high density welding subassembly machine requiring minimal factory floor space, requiring minimal operational manpower, requiring a relatively low initial capital investment, providing easy maintenance, and minimizing safety and environmental concerns. 
         [0006]    The invention provides a method of welding motor vehicle components at a weld station. The method comprises providing a pallet having a plurality of successive substations for receipt of component subassemblies; reciprocally moving the pallet back and forth between a load/unload station and the weld station; while the pallet is at the load/unload station, moving the component subassembly at each substation to the next successive substation and adding a further component to each moved component subassembly; and while the pallet is at the weld station, welding each component subassembly at each substation of the pallet. 
         [0007]    According to a further feature of the invention methodology, the weld station substations includes a plurality of substations corresponding to the plurality of substations; as the pallet arrives at the welding station, the pallet substations are aligned respectively with the weld station substations; and a welding operation is performed at each welding station substation unique to the component subassembly positioned on the pallet at the weld station substation. 
         [0008]    According to a further feature of the invention methodology, the steps of moving the pallet back and forth between the weld station and the load/unload station, welding each component subassembly at each substation of the pallet while the pallet is at the weld station, and moving each welded component subassembly to the next successive weld station of the pallet and adding a further component to the moved subassembly while the pallet is at the load/unload station, are repeated until a final welded subassembly is presented at the final substation with the pallet positioned at the load/unload station, whereafter the final welded subassembly is removed from the pallet for use in further motor vehicle assembly processes. 
         [0009]    According to a further feature of the invention methodology, the pallet has at least first, second, and third substations and wherein, as the pallet is positioned at the load/unload station, a subassembly consisting of components A/B/C/D is removed from the third substation; a subassembly consisting of components A/B/C is moved from the second substation to the third substation; a new component D is added to the subassembly A/B/C positioned at the third substation; a subassembly consisting of components A/B is moved from the first substation to the second substation; a new component C is added to the subassembly A/B positioned at the second substation; and new components A and B are loaded onto the first substation. 
         [0010]    According to a further feature of the invention methodology, the pallet comprises a first pallet and the method further comprises providing a second pallet reciprocally movable between a load/unload station and the weld station and having a plurality of successive substations for receipt of component subassemblies; alternately moving each pallet from its load/unload station to the weld station while moving the other pallet from the weld station to its load/unload station; and while each pallet is at the load/unload station, moving the component subassembly at each substation to the next succeeding substation and adding a further component to the moved subassembly. 
         [0011]    According to a further feature of the invention methodology, each pallet has its own load/unload station and the load/unload stations and the weld station are in linear alignment with the weld station positioned between the load/unload stations. 
         [0012]    The invention further provides an apparatus for welding motor vehicle components at a weld station. The apparatus of the invention comprises a weld station; a load/unload station; a pallet mounted for reciprocal movement between the load/unload station and the weld station and having a plurality of successive pallet substations thereon for receipt of component subassemblies; and a transfer system proximate the load/unload station operative with the pallet positioned at the load/unload station to move the component subassembly at each substation to the next successive substation and add a further component to each moved subassembly so that the component subassembly at a particular pallet substation includes one more component than the subassembly at the immediately preceding substation and one less component than the component subassembly at the immediately succeeding substation. 
         [0013]    According to a further feature of the invention apparatus, the transfer system includes robotic devices positioned at the load/unload station. 
         [0014]    According to a further feature of the invention apparatus, the apparatus further includes a storage structure positioned proximate the load/unload station and storing inventories of components for use in forming the component subassemblies. 
         [0015]    According to a further feature of the invention apparatus, the apparatus further includes a conveyor positioned between the storage structure and the load/unload station and including a run positioned proximate the storage structure for receipt of components from inventory and a run proximate the load/unload station for delivery of components to the load/unload station for loading onto the pallet substations by the transfer system. 
         [0016]    According to a further feature of the invention apparatus, the pallet includes an initial substation, a final substation, and intermediate substations; the transfer system is operative to move component subassemblies successively from the initial substation to the final substation; and the transfer system is further operative to remove a final welded component subassembly from the final substation for use in further motor vehicle assembly processes. 
         [0017]    According to a further feature of the invention apparatus, the load/unload station comprises a first load/unload station, the pallet comprises a first pallet, and the transfer system comprises a first transfer system; and the apparatus further includes a second load/unload station, a second pallet mounted for reciprocal movement between the second load/unload station and the weld station and having a plurality of successive substations, and a second transfer system operative with the second pallet positioned at the second load/unload station to move the component subassemblies at each substation to the next successive substation and add a further component to each moved subassembly. 
         [0018]    According to a further feature of the invention apparatus, the apparatus further includes tooling at each pallet substation configured to receive and accurately position the components of the specific component subassembly at that substation. 
         [0019]    According to a further feature of the invention apparatus, while one pallet is at its load/unload station for movement of the subassemblies between the successive substations, the other pallet is at the weld station for welding of the component subassemblies at the substations. 
     
    
     
       BRIEF SUMMARY OF THE DRAWINGS 
         [0020]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views and wherein: 
           [0021]      FIG. 1  is a perspective view of the subassembly machine of the invention; 
           [0022]      FIGS. 2 ,  3  and  4  are somewhat schematic views showing steps in the invention methodology; 
           [0023]      FIG. 5  is a perspective view of a weld station forming a part of the invention welding machine; 
           [0024]      FIG. 6  is a further perspective view of the invention welding machine; 
           [0025]      FIG. 7  is an elevational view of the weld station; 
           [0026]      FIGS. 8 ,  9  and  10  are detail views showing subassembly enablers; and 
           [0027]      FIGS. 11 ,  12 ,  13  and  14  are diagrammatic views illustrating the invention methodology. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    The high density welding subassembly  10  of the invention, broadly considered, includes a weld station  12 , a left load/unload station  14 , a right load/unload station  16 , a left transfer system  17 , and a right transfer system  18 . 
         [0029]    Welding station  12  includes a pair of longitudinally extending, of laterally spaced scaffold structures  19  defining a weld area WA therebetween and a plurality of robots  20  supported on the scaffold structure. For example, each scaffold structure may support welding robots positioned on and extending upwardly from the base  21  of the scaffold structure in longitudinally spaced relation and three inverted welding robots extending downwardly from the top wall  22  of the scaffold structure in longitudinally spaced relation. Each scaffold structure  19  further includes leg support structures  23  extending downwardly from the top wall  22  to define an open working space WS below the top wall and the inverted robots  20  carried by the top wall  22  extend downwardly into the working space WS. The lower operative ends  20   a  of the inverted robots extend into the weld area WA between the laterally spaced scaffold structures for coactions in performing welding or other operations on motor vehicle components positioned in the weld area. The weld station comprises a plurality of successive substations and may, for example, include five substations including a weld station substation  10  (WSS 10 ). WSS 20 , WSS 30 , WSS 40  and WSS 50 , each including one or more welding robots and one or more positioning robots. Each scaffold structure further includes suitable control panels  24  positioned on the top walls  22  proximate the outboard faces of the scaffold structures. The number, spacing and functioning of robots at each substation will, of course, vary depending upon the particular application. 
         [0030]    Left load/unload station  14  includes a pallet  24  mounted on a base pallet structure  26  for reciprocal powered movement on tracks or rollers between load/unload station  14  and weld station  12  and including a plurality of successive pallet substations corresponding to the weld station substation and including a left pallet substation  10  (LPSS  10 ), LPSS 20 , LPSS 30 , LPSS 40  and LPSS 50 . Unique component tooling LAB, LABC, LABCD, LABCDE, and LABCDEF is positioned at the five left pallet substations, respectively. 
         [0031]    Left transfer system  17  includes robot base support structures  28 / 30  on opposite sides of the pallet base structure, spaced load robots  32 / 34  slidably positioned on robot base structure  28 , unload robot  36  slidably positioned on robot base structure  30 , and unload robot  38  mounted on robot slide base structure  40  for selective sliding movement toward and away from the pallet structure. 
         [0032]    Right load/unload station  16  is similar to station  14  and includes a pallet  50  mounted on a pallet base structure  52  for reciprocal powered movement on tracks or rollers between load/unload station  16  and weld station  12  and including a plurality of successive pallets substations corresponding to the weld station substations and to the left pallet substations and including a right pallet substation  10  (RPSS  10 ), RPSS 20 , RPSS 30 , RPSS 40 , and RPSS 50 . Unique tooling RAB, RABC, RABCD, RABCDE, and RABCDEF (corresponding respectively to tooling LAB, LABC, LABCD, LABCDE, and LABCDEF) is positioned at the five right pallet substations respectively. 
         [0033]    Right transfer system  18  includes robot base structures  54 / 56  on opposite sides of the pallet base structure, a pair of longitudinally spaced load robots  58 ,  60  slidably mounted on the robot base structure  54  and an unload robot  64  mounted on a slide  66  for sliding movement toward and away from the pallet base structure. 
         [0034]    Subassembly machine  10  further includes an endless conveyor  70  positioned proximate robot base  28  of left transfer system  17 , a further endless conveyor  72  positioned proximate robot base  54  of right transfer system  18 , a component inventory storage structure in the form of a row of dunnage containers or racks  74  positioned in outboard relation to conveyors  70 ,  72 , and a plurality of dunnage racks  76  positioned on opposite sides of each slide  40 / 66 . 
         [0035]    Endless conveyor  70  includes a run  70   a  positioned proximate and parallel to inventory containers  74  and a run  70   b  positioned proximate and parallel to robot base  28 . Endless conveyor  72  includes a run  72   a  positioned proximate and parallel to inventory containers  74  and a run  72   b  positioned proximate and parallel to robot base  54 . 
       Operation 
       [0036]    In overview, while components on pallet  24  from station  14  are positioned in the weld station for suitable welding operations ( FIG. 3 ), component subassemblies on pallet  50  in the load/unload station  16  are being unloaded and loaded, whereafter, following completion of the welding operations on the components subassemblies positioned on the pallet  24 , that pallet is shuttled back to the load/unload station  14  for suitable unloading and loading ( FIG. 2 ) while the component subassemblies on pallet  50  are shuttled to the weld station for suitable welding operations and this sequence is continued until the job in question is completed. To facilitate the shuttling movement of the pallets, the longitudinal center lines of stations  12 ,  14 ,  16  are aligned so that the shuttling movement of the pallets is linear straight line and direct. 
         [0037]    More specifically, at start-up of a particular job, pallets  24 / 50  are empty. Initially, and with particular reference to  FIGS. 11 ,  12 ,  13  and  14 , two body sheet metal components A/B are loaded onto substation RPSS  10  of pallet  50  utilizing load robots  58 / 60  receiving parts from conveyor  72 , whereafter the pallet is shuttled to the weld station for welding of components A/B at weld station substation WSS  10 . While this welding operation is occurring, components A/B are loaded onto LPSS  10  of pallet  24  utilizing load robots  32 / 34  retrieving parts from conveyor run  70   b.  When the welding operation is complete, pallet  50  is shuttled back to station  14  and pallet  24  is moved to the weld station for welding of components A/B at WSS  10 . As this welding is taking place, welded components A/B are moved to RPSS 20 , a third component C is added to components A/B at RPSS 20  and new components A/B are loaded onto RPSS  10 , whereafter following completion of the welding, pallet  24  is shuttled back to station  14  and pallet  50  is shuttled to the weld station for welding of components A/B/C at WSS 20  and welding of components A/B at WSS 10 . While this welding is taking place, welded components A/B at LPSS  10  of pallet  24  are moved to LPSS 20 , a third component C is added to components A/B at LPSS 20 , and new components A/B are loaded onto LPSS  10  whereafter, following completion of the welding, pallet  50  is shuttled back to station  16  and pallet  24  is shuttled to the weld station for welding of components A/B/C at WSS 20  and welding of components A/B at WSS  10 . As this welding is taking place, welded components A/B/C at RPSS 20  of pallet  50  are moved to RPSS 30 , a fourth component D is added to welded components A/B/C at RPSS 30 , welded components A/B at RPSS  10  are moved to RPSS 20 , a third component C is added to welded components A/B at RPSS 20 , and new components A/B are loaded onto RPSS  10 . 
         [0038]    This shuttling and loading sequence is continued until welded components A/B are positioned at substation  10  of each pallet, welded components A/B/C are positioned at each substation  20  of each pallet, welded components A/B/C/D are positioned at substation  30  of each pallet, welded components A/B/C/D/E are positioned at substation  40  of each pallet, and welded components A/B/C/D/E/F are positioned at substation  50  of each pallet. Once each of the substations of each of the pallets is full, the sequence is as seen in  FIG. 11  where, with respect to pallet  50 , and with a fully loaded pallet  24  positioned in the weld station for welding of respective components A/B, A/B/C, A/B/C/D, A/B/C/D/E, and A/B/C/D/E/F, welded component subassembly A/B/C/D/E/F from RPSS 50  is removed by robot  64  for placement in dunnage  74 , welded component subassembly A/B/C/D/E at RPSS 40  is moved to RPSS 50  for addition of a component F, welded component subassembly A/B/C/D at RPSS 30  is moved to RPSS 40  for addition of a component E, welded component subassembly A/B/C at RPSS 20  is moved to RPSS 30  for addition of a component D, welded component subassembly A/B at substation  10  is moved to RPSS 20  for addition of a component C, new components A/B are placed at RPSS 10 , and pallet  50  is shuttled back to a weld station for welding operations on the various component combinations as pallet  24  with fully welded components shuttles back to load/unload station  14 . 
         [0039]    It will be understood that, in each case, inventories of the appropriate components A, B, C, D, E, F are provided in appropriate racks or bins in row  74  and are loaded onto conveyor runs  70   a / 70   b  for retrieval from conveyor runs  70   b / 72   b  by the load robots, and the movement of the components between substations and the addition of components at the substations is performed utilizing load robots  58 / 60  at station  16  and load robots  32 / 34  at station  14 . Unloading of welded component subassemblies ABCDEF from LPSS 50  is performed at station  14  utilizing unload robots  36 / 38  with robot  36  retrieving the welded component subassembly ABCDEF from LPSS 50 , moving slidably along track  30  to track  40 , and transferring the subassembly to robot  38  for delivery to dunnage  76 . Unloading of welded component subassembly ABCDEF from RPSS 50  is performed at station  16  utilizing unload robot  64  for delivery to dunnage  76 . 
         [0040]    It will be understood that the positioning of the various components at the various substations of the pallets is performed using dedicated tooling with tooling LAB/RAB designed to accommodate components A and B positioned at each pallet substation  10 ; tooling LABC/RABC designed to accommodate components A, B and C positioned at each pallet substation  20 ; tooling LABCD/RABCD designed to accommodate components A, B, C and D positioned at each pallet substation  30 ; tooling LABCDE/RABCDE designed to accommodate components A, B, C, D and E positioned at each pallet substation  40 ; and tooling LABCDEF/RABCDEF designed to accommodate components A, B, C, D, E and F positioned at each pallet substation  50 . 
         [0041]    It will further be understood that the robots  20  associated with each weld station substation may include positioning robots carrying positioning tooling such as the tooling  60  seen in  FIG. 9 , as well as welding robots carrying weld guns  62  as seen in  FIGS. 8 and 10 , and that robots carrying both positioning tooling and weld guns may also be employed. 
         [0042]    Typical applications of the invention machine include the formation of body side inner right-hand and left-hand, front floor subassembly, center floor assembly, dash subassembly, cowl top and cowl side subassembly, rear wheel subassembly, rear pan subassembly, rear door left-hand and right-hand subassembly, front door left-hand and right-hand subassembly, lift gate and deck lid assembly, hood assembly, and closure hemming with respect to doors, hoods, decks and lift gates. 
         [0043]    The invention high density welding machine has many advantages, chief of which is the ability to significantly reduce the required floor space for a particular job function. Further, the invention machine requires a minimum of manpower and a minimum of initial capital expenditure, and facilitates tooling maintenance and changeover since the tooling of the pallet not at the weld station is readily accessible for maintenance and changeover. 
         [0044]    In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.