GB2185942A - Installation for assembling items of vehicle bodywork - Google Patents

Abstract

An installation for the assembly of motor vehicle bodywork parts is of the type comprising a line with different working stations for a transport framework 25 moving along the said line and means for securing each such framework in position in front of each such station, in addition to a shaping and spot welding station for the different parts of the car body. Each transport framework comprises a frame 20 connected to a conveyor and supporting two frame members 25, 25a articulated thereto by their upper edges, the lower edge in each case being guided in rails, each frame member comprising a set of elastic clamps 31 of which the branches are mounted elastically in such a way that they simply hold the various parts to be assembled, the shaping station comprising a fixed structure with two planes supporting a set of shaping devices arranged in such a way that they can extend into the frame members between the elastic clamps,the fixed structure being arranged so that it can extend between the said frame members when the transport framework is in the shaping station and each shaping device having a bearing surface serving to support a portion of the external lateral surface of the bodywork parts to be assembled, a jack being provided which controls a pressure tool in order to clamp the said part against the bearing surface, the said shaping station also comprising means for tilting the frame members in such a way that the parts, which are supported by the elastic clamps, assume a position corresponding to that of the shaping devices and are engaged and shaped by these latter, while two carriages are provided which are movable perpendicularly to the direction of displacement of the transport frameworks and each of which supports spot welding units in order to assemble in one single cycle the different parts borne by the two frame members. <IMAGE>

Description

SPECIFICATION Installation for assembling items of vehicle bodywork The present invention relates to an installation for the purpose of assembling different items of bodyworkforthe construction of a motorvehicle.

The invention is concerned with installations ofthe type comprising transportframeworks, which can move along a given circuit and which are designed to accommodate the pieces of which a partofthecar body is to be made up, these frameworks being then conveyed to a "shaping station" where the pieces are assembled by a spot welding process.

Installations of this kind have long been known in the prior art but have always necessitated a considerablelabourforce. Since the introduction of "robots" attempts have been made to automate these installations to an increasing extent, and it is with this type of installation that U. & Patent 4,256,947 is concerned.

The said patent describes a system comprising a line along which transport frameworks are conveyed, each of which includes "shaping tools" serving to fix the parts to be assembled, these latter being arranged in such a way that their external faces, i.e. the sides of vehicles, in the example shown, are produced facing one another, a working station being provided into which the framework is inserted and which comprises moving doors which press the internal portions of the said parts, this station also comprising resistance welding robots operating bythespotwelding method and serving to weld the different parts of the bodyworktogether.

An installation ofthis kind suffers from numerous drawbacks and cannot ensure an even rate of production.

The fact is that each transport frame includes manual assemblytools for the parts, so that these have to be positioned with great accuracy and the operations of opening and closing thetools consumea great deal oftime.

Each transport framework is therefore specific to the particular car model to be manufactured, and even a simple change in the model involves the production of a differentframe.

The moving doors press againstthe interiorofthe part, making it impossible to shape and assemble them accurately. It is a known fact that in the construction of vehicle bodies the parts to be assembled must be placed against a support by their external surface, failing which deformations occur which render the parts useless.

Finally, the installation comprises robotsforthe spot welding, and these are known to be comparatively slow in view of the complex movements which they have to perform and the different spot-welds, which frequently occupy positions at a considerable angular distance from one another. The time for which the transport framework has to remain motionless atthe station is therefore considerable, and an assembly line ofthis kind cannot ensure the rate of outputwhich is indispensable in the car industry.In orderto overcomethis drawback the inventor proposed a line having branches with a number ofstations operating simultaneously, but this solution, farfrom improving the installation, actually renders it more complicated, increasing its cost and resulting in the risk of the production of widely differing units which can therefore no longer be mounted. It is a known factthat however much care is devoted to a manufacturing process these are still certain tolerances, so that the introduction of several different stations automatically leads to slightly different dimensions between the units manufactured at these respective production points.

The present invention seeks to provide an installation by which these various drawbacks will be remedied.

The installation according to the invention is of the type comprising a line with different working stations for the transport framework moving along the said line and means for securing each such framework in position in front of each such station, in addition to a shaping station and spot welding station forthe different parts of the car body, and is characterised by the fact that each transport framework comprises a frame connected to a conveyor and supporting two frame members articulated thereto by their upper edges, the lower edge in each case being guided in the rails, each frame member comprising a set of elastic clamps of which the branches are mounted elastically in such a way that they simply hold the various parts to be assembled, the shaping station comprising a fixed structure with two planes supporting a set of shaping devices arranged in such a way that they can extend into the frame members between the elastic clamps, the fixed structure being arranged so that it can extend between the said frame members when the transport framework is in the shaping station and each shaping device having a bearing surface serving to support a portion of the external lateral surface of the bodywork parts to be assembled, a jack being provided which controls a pressuretool in orderto clamp the said part againstthe bearing surface, the same shaping station also comprising meansfortilting the frame members in such away thatthe parts, which are supported by the elastic clamps, assume a position corresponding to that of the shaping devices and are engaged and shaped by these latter, while two carriages are provided which are movable perpendicularly to the direction of displacement of the transport framework and each of which supports spot welding units in orderto assemble in one single cycle the different parts borne bythetwoframe members.

An installation of this type enables a considerable amount oftimeto be saved, since the charging ofthe transport framework calls for no precise positive clamping action etc. Furthermore, one single shaping station is sufficient, as the shaping and assemblytime is very short, and it is therefore certain that all the parts produced will be identical.

According to a preferred feature the line is provided at each end with an elevator and an upper level comprising shunting tracks forthe storage of the transport frameworks and also a station for removing the finished parts from the frame members of the transport frameworks and from the assembly line. This arrangement results in a valuable saving of space, and the return journey of the emptytransportframeworks is effected in the upper part ofthe installation.

According to a further preferred feature the line comprisestwolongitudinal rails of U-shaped cross section forming a guide for rollers provided along the lower edge of the frame members, while at each station each rail has openings in which shoes are movable perpendicularly to the rails, the rollers coming to rest in the shoes and the said shoes being connected to motor means for selectively reducing or decreasing the distance between the shoes of one rail and the corresponding shoes of the other rail.

The invention will now be described in greater detail by reference to particular embodiments given solely as example and illustrated in the accompanying drawings, in which: Figure 1 is a schematic elevation of an installation shown in Figures 1 and 2; Figure2 is a plan view of the installation shown in Figure 1; Figure 3 is an end elevation of the installation shown in Figures 1 and 2; Figure 4 is an elevation on a larger scale, showing a portion of a transportframework; Figure 5 is an elevation of an elastic clamp; Figure 6is a schematic plan view of the guide rails forthetransportframeworks; Figure 7is an end elevation oftheshaping station; Figures 8 and 9 and 10 are elevations of different types of shaping device;; Figures 11 and 12 are elevations, thefirst showing the position of the elastic clamps on the transport frameworkand the second the position ofthe shaping devices on the plane of the shaping station; Figures 13 and 14 are schematic views showing howa part secured byan elastic clamp is taken up by a shaping device; Figure 15 is a schematic elevation showing the shaping station, thetransportframework being shown in the open position; Figure 16is an elevation showing the complete shaping station in the open position; Figure 17 is an elevation showing the complete shaping station in the welding position; Figure 18 is an elevation of the discharge station; Figure 19 is a side elevation of a detail ofthe discharge station;; Figure 20 is a section along the line XXXXof Figure 18; Figure2i isa plan viewofthe layoutofthe rail 1.

Figures 1,2 and 2 show the general layout ofthe installation line according to the invention.

A line of this kind comprises two levels A and B, level A having a rail 1 on which thetransport frameworks 2 are guided. These frameworks are provided with a conveyor, well known in the industry and not described here in detail.

The installation consists of a metallic structure 4 of which one end is provided with a conveyor 17, a vertically movable part 6 supporting a rail section 7 which, when the movable part 6 occupies its upper position, coincides with the rail 1, whereas the lower position this section 7 coincides with a rail 5 extending to the upper level B.

At its other end the installation comprises another elevator 8 with a movable part 9 which comprises a rail section which, in the upper position, can assume a position coinciding with that of the rail 1,while in the lower position it will coincide with the rail 5, each elevator being controlled from a motor 18 provided on the structure 4.

At the lower level B, two working stations 10 and 11 are provided, in addition to a shaping station 12 and welding stations 13, 14 and 15, provided with robots 16.

Each transport framework (see Figures 3 and 4) comprises a rigid metal frame 20 extending horizontally and including a device 21 by which it is suspended from the rail 1 or 5, the said frame 20 being provided, along one longitudinal side, with brackets 22 between the flanges of which lugs 24, integral with a frame member 25, are articulated to shafts 23.

Along the second longitudinal side of the frame 20, opposite that provided with the brackets 22, are brackets 26 which are traversed by shafts 27 to which are articulated lugs 28 integral with a frame member 25a identical to the frame member 25.

Each frame member 25 and 25a consists of sections assembled to form a rigid framework of which the lower edge is provided with lugs 29, loose rollers 30 rotating on the side lugs and being designed to interact with the rails provided on the groundatlevel B.

Each frame member 25 and 25a comprises a series of elastic clamps 31 arranged to secure provisionally the different parts constituting a side or a portion of a side of a motor vehicle.

For example, in the version shown in Figure 4, the side of the vehicle comprises a certain number of parts which are shaped separately and placed in the frame member 25 and 25a in a position corresponding to their assembly, so that a part 33 corresponding to the bottom of the step, the part 34 corresponding to the middle of the step and an upright 35 etc., can be treated as separate parts to be assembled. The elastic clamps 31 thus serve as preliminary positioning devices for the different parts 33 and 34 etc., and assembly workers occupying stations 10 and 11 place the different parts in the positions required, fitting them elastically into the said clamps 31.

Fig ure 5 shows on a larger scale one ofthe elastic clamps 31, comprising a plain plate 36 affixed to the corresponding edge of the frame member 25 and integral with a shaped plate 37 supporting two shafts 40 and 41 to which branches 42 and 43 respectively are hinged.

The shaped plate 37 is constructed in such a way as to present a housing 53 serving to accommodate the external surface of the profiled part 54, in the present case forming the upright of a windscreen, the said housing having two flanges 38, each supporting an adjustable stop 39.

To the shaped plate 37 are affixed two blocks 48 and 50 which support compression springs 44and 45 of which the first is designed to interact with a branch 42 in orderto apply it against the stop 39 while the second is designed to th rust the branch 43 against the corresponding stop 39.

Screws 49 and 51 are provided for the purpose of regulating the tension of the springs 44 and 45, together with a covering plate 55 to secure the branches 42 and 43 in position.

An elastic clamp of this kind enables a part, such as the profiled unit 54, to be accommodated and secured, but it also enables the said partto be extracted with relative ease.

Figure 5 shows in detail an elastic clamp 31, buta clamp of this kind will be represented schematically in the rest of the explanatory text in orderto make it easierto understand how the installation functions.

The level B comprises two rails 60 and 61 which are positioned on the ground and in which the rollers 30 ofthe frame members 25 and 25a are guided.

Each rail 60 or 61 is arranged in such a mannerthat each frame member 25 or 25a extends in a substantially vertical direction, although each ofthe stations 10-15 is provided with means by which the angular position ofthe frame members 25 and 25a can be adjusted. Figure 6 is a detailed drawing showing the said means.

Each of the stations 10-15 is provided with an electric motor 64 which drives two racks 65 and 66 via a reduction gearing. The rack 65 is integral with the bar 67 supporting two shoes 68 inserted in the corresponding openings 69 of the rail 60.

At its free end the rack 66 supports a bar 70 of which the ends are provided with two shoes 71 inserted in opening 72 ofthe rail 61.

The shoes 68 and 71 have the same cross section as rails 60 and 61 and are arranged in such a waythat when a frame member 25 and 25a has stopped atthe station 10 the rollers 30 cometo rest in the said shoes. The motor 64 can thus cause the lower edges of the frame members 25 and 25a to move farther apart or closertogether.

Atthestation 10 they are caused to movefarther apart, so that the parts 34, 35 etc., can be placed in position more easily.

As may be seen from Figure 6, each of the stations 11-15 is equipped in the same manner as the station l0toenabletheangularpositionoftheframe members 25 and 25a to be modified, andthesame reference numbers as those used forthe said station 10 have been used for each of the stations mentioned.

Figures 7,8,9 and 10 show the structure ofthe shaping station 12.

This station comprises a metal frame marked 80 as a whole and affixed to the ground, this frame having feet 81 between which the motor 64 is mounted and two inclined planes 82 and 83, the entire assembly constituting a rigid structure which is totally non-deformable.

Each inclined plane 82 and 83 includes a set of shaping devices 85 each of which is designed to receive one or more components which are supported by the elastic clamps 31 and to givethem theirfinal shape and hold them together during a first spot welding operation.

Various parts 34,35,54 etc., are produced bythe stamping process and are undercut to enable the stamping tool to be released. Certain portions of these components may likewise be fitted in. The shaping devices 85 enable the components to be given theirfinal shape and firmly held together during the welding operation.

Figures 8,9 and 10 show different types of shaping devices 85.

The shaping device in Figure 8 comprises a fixed portion 86 having bearing surfaces 87,88 and 89 on which, in the example illustrated in the present case, two stamped components marked 90 and 91 come to rest. These components may correspond, for example,tothepart34shown in Figure 4.

To the body 86 is affixed the body 92 of a pneumatic jack provided with ends 100 and 111 designed to be selectively connected to a source of compressed air by which a pressure tool 95 isto be tilted in an active direction (arrowf) or else released.

Needless to say, when one of the ends is connected to the compressed air source the other is in the open.

The pressure tool 95 has a first counter-bearing surface 96 designed to tighten a portion of the part 90 against the bearing surface 87, a second cou nter-bearing surface 97 designed to tig hten the central part of the component 90 against the bearing surface 88 and finally a nose 98 which keeps the parts 90 and 91 applied against each other.

Figure 9 shows an alternative version of the shaping device 85 designed, for example, to accommodate the central foot 34 formed by a first U section 110 closed by a second such profiled part 111.

The shaping device in Figure 9 comprises a body 1 12 with a supporting housing 113 and a pneumatic jack 114 comprising a pressure tool 115 designed to tighten the two profiled parts 110 and 111 against each other and againstthesupporting housing 113.

Figure 10 also shows an alternative version of a shaping device 85 constructed to support, for example, one ofthe rear parts of the car bodywork, the said part being marked 117.

Theshaping device in Figure 10 comprises a body 1 18 with a bearing surface 1 19 forthe part 1 17 and a pneumatic jack 116 fitted with a pressure tool 106 serving to secure the part 117 in position againstthe bearing surface 119.

As may be seen from Figures 11 and 12, the elastic clamps 31 and the shaping devices 85 occupy positions such that when a frame member 25 and 25a is situated opposite an inclined plane 82 and 83 it may be moved closer to the latter without the risk that the shaping devices 85 will make impact on the framememberortheclamps3l.

As may be seen from Figure 15, when a transport framework 2 reaches the shaping station it occupies an inclined position corresponding to the charging position of the stations 10 and 11,so that the frame members 25 and 25a guided on the rails 60 and 61 can pass along the shaping devices 85. When the frame members 25 and 25a are situtated opposite the inclined planes 82 and 83 the rollers 30 are positioned in the corresponding shoes 68 and 71 and the support framework 2 is at a stand-still. The motor 64 tilts the frame members 25 and 25a on the shafts 23 and 27 in the direction of the arrows g.During this tilting operation (see Figures 13 and 14)the parts 33, 34,35 etc., which are secu red in position by the elastic clamps 31, come to rest against the bearing surfaces ofthe shaping devices88,119 and 113, after which the jacks 92, 114 and 116 are actuated so that the pressure tools 95, 115 and 106 press the parts and secure them in position during the welding operation.

As the elastic clamps 31 just suffice to secure the parts in position without subjecting them to any strain,they do not form any obstacle to the shaping and tightening effected bythe shaping devices 85.

When the welding is carried out the assembly shows a certain degree of firmness and can pass onto the various subsequent stations. After the welding the pressure toor95, 1 1 5 and 106 of the shaping device 25 is released andtheframe members 25 and 25a of the transportframework 2 after returned to their initial position by the shoes 68 and 71, which are thrust bythe racks 65 and 66 actuated bythe corresponding motor 64.

Figures 16 and 17 showtheshaping station 12 in its entirety. This station comprises a system 129 for locking the transport framework 2, interacting with a stud 132 of the frame 20, to be described in greater detail in connection with Figures 18 and 19.

On one side of the frame 80 is a carriage 120 supported bysmall wheels 125 moving over rails 121 and supporting a frame 122 to which are affixed resistance welding units 123 operating by the spot welding method, these welding assemblies 123 being arranged to form spot-welds serving to assemble the various components forming a side or a portion of a side of the vehicle. These assemblies 123 are designed to produce the spot-welds in one single cycle. A rack 124, with which a pinion 105 driven by an electric motorwith a reduction gearing 128 interacts,is mounted along a rail 121.

A second carriage 126 is provided on the opposite side to the carriage 120 and supports resistance welding units 127 operated bythespot-welding method, these latter being designed to effect, in one single cycle, the assembly of the various components supported by the frame member 25a.

The carriage 126 is supported by small wheels 1 25a guided on the rails 121a, the entire assembly being controlled from an electric motor 128a to which is keyed a pinion 105a interacting with a rack 124a. The carriages 120 and 126 can bemovedfartherapartor closertogether simultaneously in such a way that the welding units 123 and 127 will likewise operate simultaneously.

Itwill be noted that the carriages 120 and 126 can be positioned at a considerable distance from the frame 80, thus giving easy access to the welding units 123 and 127, so that they can be replaced, modified, separated or placed in different positions in order to construct other vehicle models. The carriages 120 and 126 can be moved separately.

Afterwelding units 123 and 127 have assembled the componentstheframe members 25 and 25a are returned to the initial position and the transport framework is moved to the post 13, where robots 16 produce some of the additional spot-welds, after which the transport framework 2 is conveyed to the station 14, where robots 16 produce still further spot-welds, and finally to the station 15,where further robots 16 produce the final spot-welds, the sides of the vehicles then being completed and the transport framework 2 reaching the elevator 8, where it is returned to the upper level A. On this level there is a discharge station 130 with two manipulators 131.Figure 18 only shows one of the manipulators, the other being identical thereto and positioned symmetrically in relation to a vertical plane passing through the longitudinal axis of the frame 20.

At the upper level Aa locking system 129 is provided forthe transportframework 2, such a system being provided in particular atthe shaping station 12 and the various stations 10, 11, 13, 14 and 15, in order to ensure the accurate positioning ofthe transport framework 2 at the various stations. This locking system 129 is supported by a metal structure 133 of which the upper part has a guide slot 134 which is formed by two bars 135 and which is engaged by a stud 132 provided in the lower intermediate middle portion of the frame 20, while the rollers 30 are guided in rails 136 provided atthe said upper level A.

The structure 133 supports a jack 137 of which the position rod 138 is connected to a slide 139 guided in sleeves 140 borne by a plain plate 141 integral with thestructure 133,thefreeendoftheslide terminating in a bolt 143 formed by a U-shaped piece with divergentflanges, serving to lockthe stud 132 in position.

The manipulator 131 comprises a link 145 ofthe dove-tailed type, in which is guided a carriage 146 having a screw threading 147 into which is screwed a worm 148 driven by a motor 149 with a reduction gearing.

The carriage 146 comprises a frame 150 on a shaft 151 to which is articulated a first connecting rod 152 of which the other end is articulated to a shaft 153 borne by a bracket 159 provided atthe free end ofthe piston rod 154 of the jack 155 of which the body is articulated to a shaft 156.

To the shaft 153 is hinged one of the ends of the connecting rod 161 of which the other end is hinged to a shaft 162 borne by a counter-shaft 163 hinged to a shaft 164 on the frame 150 and connected by a shaft 1 65 to a a movable support 166. The movablesupport 166 is likewise supported by a connecting rod 168 articulated by one end to a shaft 167 oftheframe 150 and bythe other end to a shaft 169 provided on the said movable support. This provides a kind of deformable parallelogram. The frame 150 comprises a stop 170 designed to come to restagainstthe lower edge of the side of the vehicle, while the movable support 166 is provided, in the vicinity of its upper end, with a stop 171 designed to interact with the upper edge of the side vehicle.

The link 145 slants towards the rail 136.

Th e tra nspo rtf ra mework 2 to be discharged arrives opposite the station 130 and is locked by the bolt 143, which interacts with the stud 132, after which the manipulator 131 is operated in such a way that the carriage 146 will move towards the transport framework 2, the stop 170 coming to rest againstthe internal lower edge of the side of the vehicle, the jack 155 then being actuated in such a way as to shorten the rod 154, sothatthe movable support 166 ascends and the stop 171 comes to rest against the internal surface ofthe upper edge of the side of the vehicle, after which this latter component can be extracted from the elastic clamps 31 by which it is held.The motor 149 is then actuated in such a way as to turn the screw 148 in the direction required in orderto move the carriage 146 away from the transport framework 2, so that the side of the vehicle will be moved as far as the conveyor 176, which takes it up and conveys ittowards further stations. Needless to say, the movable support 166 is returned to its initial position in order to enable the side of the vehicle to be released When attached to the conveyor 176.

The shaping station 12 is protected by grids 180 in order to protect the personnel.

Each of the stations 10,11,12,13, and 15 comprises a locking system 129 serving to ensure thattheframe members 125 and 125a will invariably occupy identical positions during operation effected at the different stations.

The installation functions as follows: Afreetransportframework 2 is moved over the rail 1 in such a way asto convey it to the elevator 17, which lowers the movable part 6 with the said framework 2, which is conveyed to the first station 10. Assembly workers on each side of this station take components out of the troughs standing behind them and placethem in a certain order in the frame members 25 and 25a, so that the said components will be held by the eiastic clamps 31.

The station 10 enables each frame member 25 and 25a to be partly fed, during which operation the transportframework 2 is locked by a device 129 (see Figure 19) while the frame members 25 and 25a are tilted by the shoes 68 and 71 in orderto make them more accessible to the assembly workers.

The transport framework 2 is then moved to the station 11, where assembly workers finish feeding it with stamped components held by the elastic clamps 31. The frame members 25 and 25a occupy a slanting position in this station likewise, and the transport framework 2 is positioned by a locking system 129.

When the tra nsport fra mework 2 has been completely fed with stamped components it is moved to the shaping station 12 and brought to a stop in a favourable position bythe locking system 129 and the lower edges of the frame members 25 and 25a are moved closer together by the shoes 68 and 71 (see Figures 16 and 17). During the tilting of the frame members 25 and 25a the shaping devices 85 shape the components and clamp them in the final position, afterwhichthecarriages 120 and 126 are moved closer together in order to place the welding units 123 and 127 in suitable positions.The different welding units 123 and 127 produce spot-welds in orderto assemble the different components together, afterwhich the carriages 120 and 126 a re moved away from each other and the frame members 25 and 25a then returned to their initial position by the shoes 68 and 71. To enablethis operation to be carried out the shaping units 85 are opened and the components, which nowform an assembly, having been assembled by welding, and still held by the elastic clamps 31, are released from the shaping devices 85.

The locking system 129 is unlocked and the transportframework 2 moved to the station 13, where it is clamped by a locking system 129, robots 16 effecting the different spot-welds required to obtain a perfectly rigid component.

Finally, the transport framework goes to the stations 14and 15, where further robots 16form further spot-welds.

Afterthese latter operations the transport framework 2 is placed in the elevator 9 in orderto be conveyed to the upper level A, where it is conveyed to the station 130 (see Figures 18,19 and 20) where the manipulator 131 releasesthefinished components and deposits it on the conveyor 176.

The transport framework 2 is then moved along the rail 1 into a waiting position for a further cycle of operation.

Figure 21 is a planned view of the layout of the rail 1. This rail may be provided, in an intermediate part, with three tracks 181,182, 183, which form shunting tracksforthree different types of transport framework 2, for example.

On the same assembly line it may be necessaryto construct motor vehicle sides showing certain differences, e.g. a vehicle with a rear enclosure and another vehicle with a rear boot. The components forming these two types of vehicles are thus slightly different, so that the frame members 25 and 25a have to be provided with different elastic clamps 31.

Transportframeworks 2 for the different models of vehicles may thus be provided on the different shunting tracks 181,182 and 183.

The transport framework corresponding to a certain model may be ofadifferentcolourfromthat corresponding to another model, so that the assembly workers at stations 10 and 11 can feed it with the correct item.

If the shaping devices 85 have to be arranged differently for the different models a number of shaping stations 12 can be provided on one and the same line, each one corresponding to a certain model to be manufactured.

The installation according to the invention offers a number of advantages. In particular, it enables the time requiredforthe production of a bodywork component, such as the side of a vehicle, to be shortened considerably. It ensures that the components constructed will all be identical, owing to the fact that one single shaping station is sufficient forthemanufactureofthebodyworkpartin question. It also enables space to be saved, since it can be constructed at two levels. Finally, it can be easily and rapidly modified when vehicles of a different model are to be manufactured.

Needless to say, the invention is not confined to the embodiments described and illustrated.

Numerous modifications can be made thereto in matters of detail without thereby departing from the scope of the invention.

Claims (4)

1. Installation for the assembly of motor vehicles bodywork parts, of the type comprising a line with different working stations for a transport framework moving along the said line and means for securing each such framework in position in front of each such station, in addition to a shaping and spot welding station forthe different parts of the car body, wherein each transportframeworkcomprises a frame connected to a conveyor and supporting two frame members articulated thereto by their upper edges, the lower edge in each case being guided in rails, each frame member comprising a set of elastic clamps ofwhich the branches are mounted elastically in such a way that they simply hold the various parts to be assembled, the shaping station comprising a fixed structure with two planes supporting a setofshaping devices arranged in such a way that they can extend into the frame members between the elastic clamps, the fixed structure being arranged so that it can extend between the said frame members when the transport framework is in the shaping station and each shaping device having a bearing surface serving to support a portion ofthe external lateral surface of the bodywork parts to be assembled, a jack being provided which controls a pressuretool in orderto clamp the said partagainst the bearing surface,the said shaping station also comprising meansfortiltingtheframemembersin such a way that the parts,which are supported by the elastic clamps, assume a position corresponding to that of the shaping devices and are engaged and shaped by these latter, while two carriages are provided which are movable perpendicularly to the direction of displacement of the transport frameworks and each of which supports spot welding units in orderto assemble in one single cycle the different parts borne by the two frame members.

2. Installation for the assembly of motor vehicle bodywork parts in accordance with claim 1, wherein the line is provided at each end with an elevator and an upper level comprising shunting tracks forthe storage of the transport frameworks and also a station for removing the finished parts from the frame members of the transport frameworks and from the assembly line.

3. Installation forthe assembly of motor vehicle bodywork parts in accordance with claim 1 or 2, wherein the line comprises two longitudinal rails of U-shaped cross section forming a guide for rollers provided along the loweredgeoftheframe members while at each station each rail has openings in which shoes are movable perpendicularlyto the rails, the rollers coming to rest in the shoes and the said shoes being connectedto motor means for selectively reducing or decreasing the distance between the shoes of one rail and the corresponding shoes of the other rail.

4. Installation for the assembly of motor vehicle bodywork parts substantially as shown in the accompanying drawings and described herein with reference thereto.