Patent Publication Number: US-6712285-B2

Title: Process and station for changing product in an installation for spraying coating product

Description:
The invention relates to a process and to a station for changing product in an installation for spraying coating product. 
     BACKGROUND OF THE INVENTION 
     It is known, for example from EP-A-0 274 322, to use a reservoir, mounted at the end of an arm of a multi-axis robot, to supply coating product to a pneumatic or rotary sprayer supported by this arm, in particular in the case of an installation for spraying an electrically conducting coating product by means of a sprayer of electrostatic type. This state of the art provides using a sprayer fixed on the arm of the robot, cleaning it and filling it with fresh coating product as a function of needs. According to a first variant, the reservoir is removably mounted on the sprayer and a plurality of reservoirs are used as a function of the coating product chosen. According to a second variant, two reservoirs are used alternately. 
     BRIEF SUMMARY OF THE INVENTION 
     In any case, it is necessary to clean the sprayer, which is permanently mounted on the arm of the robot, and prime it with fresh coating product. These operations of rinsing and priming of the sprayer are relatively long, while the time allocated for changing coating product tends to decrease. In effect, in the case of an automobile vehicle production line, the tendency is to increase the production rates or the speeds of advance of the conveyors, which may be of the regularly advancing type or of the “stop and go” type, the coating product being changed in a period of time corresponding to the space separating two consecutive vehicle bodies, the time available being all the shorter as the speed of conveyance increases. 
     In addition, the losses of coating products during filling of the reservoir and priming of the sprayer should be minimized, as well as the consumption of cleaning product necessary to avoid a mixture and/or pollution between two coating products used successively with the sprayer. 
     Such consumption should therefore be reduced to a maximum while conserving systems of supply of coating product and of cleaning product which are reliable and of moderate cost. 
     It is a more particular object of the present invention to overcome these problems and respond to the requirements by proposing a novel process and a novel station for changing coating product, which allow a rapid change of product, while the quality of cleaning effected remains optimum and the consumption of cleaning product and of coating product is substantially reduced with respect to known systems. 
     To that end, the invention relates to a process for changing product in an installation for spraying coating product, comprising at least one robot, adapted to displace a first sprayer and a first reservoir associated therewith opposite objects to be coated,. This process which includes: 
     a step of bringing this reservoir towards a suitable area of a cleaning/filling station, 
     a step of separating a first sub-assembly comprising the first reservoir and the first sprayer with respect to the robot, 
     a step of connecting with the robot a second, similar, sub-assembly comprising a second reservoir and a second sprayer, this second sub-assembly being adapted to be used for spraying coating product during cleaning and/or filling of the first reservoir and the first sprayer, and 
     a step of cleaning and/or filling the first reservoir and the first sprayer in the said area; 
     is characterized in that it comprises the steps of: 
     positioning a coating product supply unit equipped with a plurality of outlets by displacing this unit in a first direction, so that a predetermined outlet of this unit is disposed opposite the first sub-assembly; 
     displacing, in a second direction substantially perpendicular to the first direction, a structure defining at least two receiving areas of said sub-assemblies, so as to reach a position of connection of the sub-assembly with said unit. 
     Thanks to the invention, one can proceed with cleaning the first reservoir and filling it with fresh coating product in masked time. Likewise in masked time, one proceeds with the cleaning of the sprayer and priming thereof with the new coating product, with the result that the only steps of the cleaning/filling process which are to be taken into account in the calculation of the duration of the chance of product are the steps of separation of the first sub-assembly from and of connection of the second sub-assembly on the arm of the robot. 
     The fact of using a coating product supply unit equipped with a plurality of outlets makes it possible to dispense with the use of a common collector, which would have to be cleaned when two different coating products are successively used, this making it possible to reduce the consumption of products, particularly by the elimination of a pipe between a product change block and the cleaning/filling station. The positioning of this second unit with respect to the sub-assembly also makes it possible to use a single unit of this type for the selective supply of the first or of the second sub-assembly. 
     According to advantageous aspects of the invention, the process incorporates one or more of the following characteristics: 
     The operations of separation of the first sub-assembly with respect to the robot and of connection of the second sub-assembly with the robot are carried out within an area of activity of the robot while the operations of positioning the first sub-assembly and the second unit and the operations of connection, of cleaning and/or of filling are carried out outside this area of activity thanks to a movement of the structure in two orthogonal directions. Area of activity is understood to mean the volume in which the arm of the robot is capable of moving. 
     The process comprises a step consisting of displacing, in the first direction, said structure, so as to place the area of this structure including this sub-assembly opposite a cleaning product supply unit, the displacement of this structure in the second direction making it possible to reach a connection position of the sub-assembly with this cleaning product supply unit. Thus, the positioning of the first sub-assembly opposite the cleaning product supply unit makes it possible to use a single unit for alternately cleaning the first or the second sub-assembly which are each located in a receiving area devoted thereto. 
     The process consists in connecting at least one of the above-mentioned units to the sub-assembly by displacement of connection means in the second direction. 
     The process consists in continuously supplying the first sub-assembly with air for forming a bearing and/or with air for driving a turbine of the sprayer as soon as it is deposited in a reception area and until it is withdrawn therefrom. This makes it possible to avoid a risk of “squeezing” an air bearing in the event of sudden rupture of its supply upon disconnection and re-connection of the sub-assembly with respect to the arm of the robot. The fact of permanently supplying a turbine with driving air enables its speed of rotation to be maintained at a value of the same order of magnitude as the speed used for spraying. The time for resumption of speed of the turbine after re-connection of the sub-assembly on the robot arm after the cleaning/filling operation is thus saved. In practice, the turbine of the sprayer of the first sub-assembly is continuously maintained in rotation during the operations of positioning, connection, cleaning and/or filling. 
     The invention also relates to a product changing station in an installation for spraying coating product, which carries out the process described hereinabove. This station comprises at least two areas for cleaning/filling the reservoir, adapted each to receive a sub-assembly formed by a reservoir and a sprayer while this sub-assembly is disconnected from the robot, means for cleaning and/or filling the reservoir and/or the sprayer in each of these areas being provided. These areas are adapted to be brought into a position of connection of a sub-assembly disposed in one of them with the above-mentioned cleaning and/or filling means, while these means comprise at least one unit mobile in a first direction, provided with a plurality of outlets and adapted to dispose a predetermined outlet of this unit in a position of connection to the sub-assembly. 
     The mobility of the areas for receiving the sub-assemblies and the second unit makes it possible to reduce the lengths of the pipes supplying cleaning product and/or coating product, i.e. the parts in course of manufacture and the quantities lost upon each change of product. The connection may then take place by the displacement of the appropriate area mentioned above, perpendicularly to the first direction. 
     According to advantageous aspects of the invention, the station incorporates one or more of the following characteristics: 
     The areas of reception of sub-assemblies are defined by a structure mobile with respect to a support in a first direction while this support is mobile with respect to the robot in a second direction substantially perpendicular to the first direction. 
     The cleaning and/or filling means comprise a first unit adapted to deliver to the sub-assembly at least one cleaning fluid, this first unit being disposed opposite the sub-assembly in its position of connection, and a second unit, adapted to deliver to the sub-assembly a predetermined coating product, this second unit being mobile with respect to the first unit. The station therefore allows a positioning of each of the areas of reception of the sub-assemblies opposite the first unit and the second unit with respect to the first unit, in order to allow a connection of each of these units with the sub-assembly received in the area in question. In that case, the second unit advantageously comprises a plurality of modules supplied with coating product and adapted to be selectively connected to the sub-assembly, these modules being juxtaposed in a direction of displacement of the second unit. Thanks to this arrangement, an indexation of the position of the second unit makes it possible to use one or the other of the above-mentioned modules with a view to supplying the sub-assembly with coating product. Certain of these modules may be supplied by means of circuits for circulation of product, for the coating products most often used, while at least one other module is supplied from at least one coating product changing block, for the coating products used least often. In that case, the other module is advantageously provided with means for connection to an element supplied with coating products from the product changing block, this element being mobile in a direction substantially perpendicular to the direction of displacement of the second unit. 
     The first unit may comprise a connection element applied in the direction of the sub-assembly with a view to their connection. 
     Means are provided, for supplying air forming a bearing and/or air driving a sprayer turbine of a sub-assembly in place in one or the other of the receiving areas. In that case, a sensor for detecting the presence of a sub-assembly in each of the areas is advantageously used. 
     The invention will be more readily understood and other advantages thereof will appear more clearly on reading the following description of an embodiment of a product change station and of its process of implementation according to the invention, given solely by way of example and made with reference to the accompanying drawings, in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 schematically shows an installation for spraying coating product, incorporating a station according to the invention, during operation. 
     FIG. 2 is a partial perspective view, with parts torn away, of a part of the product change station and of a part of a robot of the installation of FIG. 1, during a first step of the process of the invention. 
     FIG. 3 is a section along line III—III in FIG. 1, during a second step of the process of the invention. 
     FIG. 4 is a view similar to FIG. 3 during a subsequent step of the process of the invention. 
     FIG. 5 is a view similar to FIG. 3, with parts torn away, during a second subsequent step of the process of the invention. 
     FIG. 6 is an exploded view in perspective, from the rear with respect to FIG. 2, of certain principal elements constituting the product change station, during a subsequent step of the process. 
     FIG. 7 is a section on a larger scale along line VII—VII of FIG.  5 . 
     FIG. 8 is a section similar to FIG. 7 during filling of the reservoir of a sub-assembly with a rarely used coating product, and 
     FIG. 9 schematically shows the fluid connections used in the station of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In FIG. 1, an automat or robot  1  is disposed near a conveyor  2  conveying objects to be coated, in the present case bodies  3  of automobile vehicles. The robot  1  is of the multi-axis type and comprises a chassis  4  mobile on a guide  4 ′ extending parallel to the direction of conveyance X—X′. In order to avoid soiling the guide  4 ′, the latter may be located at a distance from the conveyor  2 , the robot  1  in that case being offset with respect to this guide. 
     A partition  5  of a booth C extends near the robot  1  parallel to direction X—X′. An arm  6  is supported by the chassis  4  and comprises a plurality of segments  6   a ,  6   b  and  6   c  articulated with respect to one another. The chassis  4  is also constituted by parts  4   a  and  4   b  articulated with respect to each other about a substantially vertical axis Z. 
     The segment  6   c  of arm  6  supports a sub-assembly  7  in which are provided a reservoir  8  of coating product and a sprayer  9 . The sprayer  9  is of the electrostatic and rotary type and it bears a bowl  9   a  intended to be driven at high speed by an air turbine  9   c  provided in the body of the sprayer  9 . 
     When an automobile vehicle body  3  is in place at the level of the robot  1 , the sub-assembly  7  is displaced opposite the body and the sprayer  9  is activated in order to coat this body with the product contained in the reservoir  8 . The quantity of product present in the reservoir  8  is adapted to the surface of the body  3  to be coated. 
     When a body has been coated, and while a second body is advancing towards the robot  1 , the latter is oriented, as shown in FIG. 2, towards a cleaning/filling station  10  located in the vicinity thereof, partially inside the booth and partially outside it. 
     As is more clearly visible in FIG. 2, this station  10  is provided with two areas  11  and  12  for receiving sub-assemblies of the type such as sub-assembly  7 . More precisely, area  11  is empty and ready to receive sub-assembly  7 , while area  12  contains a similar sub-assembly  7 ′ which comprises a reservoir  8 ′ and a sprayer  9 ′ similar to those of the sub-assembly  7 . The sub-assemblies  7  and  7 ′ may be alternately mounted on the segment  6   c  of the arm  6 , as will be explained hereinbelow. 
     In the step of the process shown in FIG. 2, the arm  6  is in a phase of approach in which it brings the sub-assembly  7  above the area  11  of the station  10 . From the position shown in FIG. 2, the arm  6  imparts to sub-assembly  7  a vertical descending movement represented by arrow F 1 , which makes it possible to bring sub-assembly  7  into area  11 . A configuration is thus attained in which a jack  13  controls a rod  14  fast with two connecting rods  15  and  16  connected by a synchronism bar  19  and fast with rings  17  and  18  disposed respectively around the openings  11   a  and  11   b  of areas  11  and  12 . In fact, areas  11  and  12  are formed by the volumes accessible from above through openings  11   a  and  12   a.    
     The sub-assembly  7  is mounted on the segment  6   c  of the arm  6  thanks to a ring  7   a  capable of a movement of rotation about axis X 1  of the sub-assembly  7 , this movement being able to be imparted to the ring  7   a  by cooperation of shapes with corresponding elements in relief provided in the ring  17 . 
     It is thus possible to disconnect the sub-assembly  7  from segment  6   c , the robot  1  then being in a position to displace this segment up to the level of sub-assembly  7 ′ where a new movement of rotation of the ring  18  controlled by the jack  13  allows a ring  7 ′ a  of the sub-assembly  7 ′ to be controlled in order to connect the sub-assembly  7 ′ with the segment  6   c . One is then in the configuration of FIG.  3 . 
     The robot  1  is then in a position to extract the sub-assembly  7 ′ from the area  12  in order to proceed with the coating of a new body, as shown in FIG.  4 . 
     While the robot is coating the body  3  thanks to sub-assembly  7 ′, it is possible to proceed, in masked time, with the cleaning of the sub-assembly  7  and with filling it with fresh coating product. This operation starts as soon as the robot  1  rotates (R) in the direction of body  3 . 
     To that end, a carriage  20  in which areas  11  and  12  are arranged, is mounted on a table  21 , the carriage  20  being mobile with respect to the table  21  parallel to axis X—X′, as represented by arrow F 2 . This makes it possible to pass carriage  20  from the position of FIG. 3 to that of FIG. 4, so that area  11  containing the sub-assembly  7  is brought to the level of a median axis X 10  of the station  10 , i.e. opposite a unit  51  for supplying the sub-assembly  7  with cleaning product and with air. Unit  51  is disposed on the median axis X 10  of the station  10  and the movements of the carriage  20  parallel to direction X—X′ may be effected in the direction of arrow F 2  or in the opposite direction, so that the areas  11  and  12  may be selectively brought opposite unit  51 . 
     In other words, as a function of the presence or absence of a sub-assembly of the type such as sub-assembly  7  in one or the other of areas  11  and  12 , it is possible to bring area  11  or  12 , in which this sub-assembly is present, opposite unit  51 . 
     From the position of FIG. 4, the table  21  is displaced, in a direction Y—Y′ substantially perpendicular to direction X—X′ and in the sense of moving away with respect to conveyor  2 , as represented by arrow F 3 . Table  21  displaces carriage  20  in the direction of arrow F 3  and then attains the position of FIG. 5 where the sub-assembly  7  is in abutment against unit  51 , which allows a fluid connection between these two elements. In this position, the table  21  and the elements that it supports are out of range of the robot  1 , i.e. outside its area of activity. 
     The table  21  passes through the partition  5  through an opening  5   a  which is then obturated by a panel  5   b  fixed on the edge of the table  21  oriented towards the robot  1 . A jack  22  makes it possible to control the displacement of the table  21  in the direction of arrow F 3  and in opposite direction. 
     When the table  21  is disposed outside the booth, the opening  5   a  is masked by the panel  5   b , as shown in FIG. 5, and it is possible to proceed with cleaning and filling of the sub-assembly  7 , being insulated with respect to the atmosphere of the internal volume of the booth. 
     The unit  51  comprises a jack  511  and a part  512  applied by the jack  511  in a direction parallel to direction Y—Y′, as represented by arrow F 4  in FIGS. 6 and 7. Jack  511  is supplied at constant pressure, which allows it to serve as damper of the movement of approach of the table  20  in the direction of arrow F 3  and to ensure tightness of the link between elements  7  and  512 . In place of the jack  511 , a damper made of foam may be used for applying the part  512  towards the sub-assembly  7 . 
     Part  512  comprises a principal body  5121  and an annex body  5122  connected by two conduits  5123  for circulation of cleaning liquid and air. The body  5122  is provided with means for connection with a plate  71  formed on one side of the sub-assembly  7  oriented towards the unit  51 . 
     As is more particularly visible in FIGS. 6 and 8, the unit  51  comprises four electrovalves  5131 ,  5132 ,  5133  and  5134  respectively controlling the supply of the sub-assembly  7  with cleaning product for hydrosoluble coating product, with cleaning product for solvented coating product, with air and, for electrovalve  5134 , the communication of part  512  with a bleed  514 . 
     Unit  51  is supplied with cleaning product and with air and connected to bleed  514  by supple conduits  515  which, in order to render the drawings clearer, are only shown in FIG.  8 . 
     On its front face  5124 , i.e. its face oriented towards the plate  71 , the part  512  is provided with two orifices  5125  and  5126  intended to come respectively opposite two orifices  715  and  716  made in the plate  71 . When the body  5122  of the part  512  is in abutment against the plate  71 , the orifices  5125  and  715  allow a circulation of a mixture of cleaning product and of coating product in the direction of the bleed  514  while orifices  5126  and  716  allow a circulation of solvent or of air/solvent trains from unit  51  towards the interior of the sub-assembly  7 . 
     Before the above-described displacement of the table  21  and of the sub-assembly  7  towards unit  51 , a second unit  52  is positioned for supplying the sub-assembly  7  with fresh coating product. 
     Unit  52  comprises a succession of modules  521  juxtaposed in a direction X 52  parallel to the direction X—X′. Modules  521  are of two types. A plurality of modules, for example fourteen, are each connected by two conduits  522  and  523  to a device (not shown) for circulation of coating product of a predetermined colour. These modules  521  are thus inserted in a loop for circulating coating product comprising conduits  522  and  523 , this construction being used for the coating products most currently used.  52 A denotes that part of the unit  52  formed by modules  521 . 
     Unit  52  also comprises two modules  524  which are not connected to conduits of the type such as conduits  522  and  523 , but of which one, so-called rear face  524   a  is provided with means for connection with a connector  525  forming the downstream end of a collector  526  of an assembly of two coating product change blocks  527 ,  527 ′. Elements  525  to  527  are mobile in direction Y—Y′, as represented by arrow F 5 , being controlled by a jack  5251 .  52 B denotes that part of unit  52  formed by elements  524  to  527 . 
     Blocks  527  and  527 ′ are connected by bundles of conduits  528  and  528 ′ to sources of coating products used less often than the coating products circulating via conduits  522  and  523 . The coating products delivered to blocks  527  and  527 ′ may therefore be considered as “rare shades”, as opposed to the “current shades” circulating in conduits  522  and  523 . Part  52 A is therefore devoted to current shades, while part  52 B is devoted to rare shades. 
     As a function of the shade of the coating product having to be supplied to sub-assembly  7  to fill it, a mobile part  529  of the unit  52  is displaced parallel to direction X 52 , as represented by arrow F 6  in FIG. 6, so that, in the case of a current shade, a module  521  of part  52 A supplied with the preselected product is disposed opposite an orifice  717  for introducing coating product into the sub-assembly  7 . 
     As is more particularly visible in FIG. 7, each module  521  comprises a valve  5211  elastically loaded by a spring  5212  in the direction of a seat  5213 . A closed valve by default is thus formed. The orifice  717  of the plate  71  allows passage of an actuator  718  fast with a piston whose displacement is controlled inside the sub-assembly  7  by any appropriate means, for example pneumatically. 
     In this way, when the block  521  corresponding to the product to be used for filling the reservoir  8  of the sub-assembly  7  is in abutment against a lower part  719  of the plate  71 , the actuator  718  may traverse the orifice  717  and the outlet orifice  5214  of the module  521  so as to push the valve  5211  against the effort of spring  5212 , as represented by arrow F 8  in FIG. 7, which allows a circulation of the coating product from module  521  towards the interior of the sub-assembly  7 . 
     When a rare shade is to be used, part  529  is displaced in the direction of arrow F 6 , so that one of the modules  524  of part  52 B is brought opposite the plate  71  and the mobile connector  525  which are then substantially aligned on the median axis X 10  of the station  10 . It is then possible to displace the connector  525 , the collector  526  and the blocks  527  and  527 ′ in the direction of module  524  as represented by arrow F 5  in FIGS. 6 and 8. 
     The connector  525  is supplied by the collector  526  with the coating product to be transferred towards sub-assembly  7 , rapid connection means being provided on the face  524   a  of the module  524  for supplying an internal chamber in which is disposed a valve  5241  similar to valve  5211  of a module  521 . As before, displacement of valve  5241  against the effort generated by a spring  5242  may be controlled by the actuator  718 , the coating product then being able to flow from module  524  towards the sub-assembly  7  though an outlet orifice  5244  of module  524 . 
     The different modules  521  and  524  are supported by an angle  529   a  forming the structure of part  529  and controlled by four jacks, of which only one appears in FIG. 5 with reference  530  and whose strokes are different, which makes it possible to obtain, for part  529  of unit  52 , sixteen positions corresponding respectively to the positioning of each of the fourteen modules  521  and each of the two modules  524  opposite part  719  of the sub-assembly  7 . 
     Blocks  527  and  527 ′ and collector  526  are supported by a plate  531  mobile with respect to a reference bracket  532  under the action of the jack  5251 , a reinforcement  533  allowing transmission of the effort generated by the jack  5251  to the plate  531  of unit  51 . 
     To allow connection of the connector  525  on one of the modules  524 , the angle  529   a  is provided with two notches  529   b  allowing access to the rear faces  524   a  of the modules  524 . 
     Unit  52  comprises two modules  524 , which make it possible to use one module  524  for the solvented coating products and the other module  524  for the hydrosoluble products. 
     Taking the foregoing into account, unit  52  being displaced in direction X 52  before the movement of the table in the direction of arrow F 3 , this movement, visible between FIGS. 4 and 5, leads to a simultaneous abutment and connection of the sub-assembly  7  on units  51  and  52 . 
     When the table  20  is in place in the position of FIG.  5  and therefore when the connection of the sub-assembly  7  with units  51  and  52  has been effected, a unit  30  for controlling the sub-assembly  7  which belongs to the station  10  is displaced in the direction of the sub-assembly  7  as represented by arrow F 9  in FIG. 1, this unit  30  being mounted on the upper face of sub-assembly  7  in place of segment  6   c . Unit  30  makes it possible to control the sub-assembly  7  in place in area  11  pneumatically and/or electrically, i.e., inter alia, to displace the piston  8   b  of the reservoir  8 , monitoring this displacement, to control the valves located in the sub-assembly  7 , and to control the turbine of this sub-assembly. 
     A single unit  30 , mobile vertically in the direction of arrow F 9  and in the opposite direction, therefore makes it possible to control sub-assembly  7  and sub-assembly  7 ′ alternately. 
     As also follows from FIG. 1, a collector  31  located at the level of the median axis X 10  of the station  10  is displaced upwardly, as represented by arrow F 10 , to cover the sub-assembly  7  from underneath and recover the products transiting via the sprayer during the cleaning/filling operations. This receptacle is advantageously equipped with nozzles for spraying cleaning product enabling the outer surface of the sub-assembly to be rinsed. It is connected, by an evacuation conduit  32 , to a bleed (ot shown). 
     As follows more particularly from FIG. 9, two air supplies  601  and  602  are provided at the level of each area  11  or  12 . These supplies  601  and  602  are intended to furnish air to the sub-assemblies  7  and  7 ′ as soon as they are in position in the areas  11  and  12  and until they are withdrawn from these areas. A sensor  603  detects the presence of a sub-assembly  7  or  7 ′ in one of the areas  11  or  12  and makes it possible to control the supplies  601  and  602  as a function of the presence of the sub-assemblies, which allows a saving of time in the cleaning/filling cycle. The air furnished by supply  601  is directed to the interior of the sub-assembly  7  or  7 ′ up to a bearing  9   b  formed between a fixed part and a rotating part of a turbine  9   c , while the air furnished by supply  602  is used for maintaining rotation of the turbine  9   c  of the sprayer  9  or  9 ′ when the sub-assembly  7  or  7 ′ is in place in area  11  or  12 . In this way, the risks of squeezing or of blocking of the bearing  9   b  are avoided and the rotation of the turbine  9   c  and of the bowl  9   a  associated therewith is maintained, which allows an efficient evacuation of the cleaning product and of the coating product used for priming the sprayer on the one hand, and avoids a time for re-acceleration of the turbine  9   c , which would be necessary if the rotation of the turbine were interrupted during the steps of cleaning and filling of the reservoir  8  and  8 ′ and of the sprayer  9  or  9 ′. 
     In other words, as soon as the module  7  or  7 ′ is mounted on the segment  6   c  of the robot  1 , it is operational for spraying coating product without waiting for the corresponding turbine  9   c  to rotate. 
     According to an advantageous aspect, the speed of rotation of the turbine  9   c  when the sub-assembly  7  or  7 ′ is in position in area  11  or  12 , may be provided to be virtually identical to the speed of rotation used for spraying coating product. 
     The unit  30  also makes it possible to supply air to the sub-assembly  7  or  7 ′, in particular to drive the turbine of the sub-assembly in question at a speed different from that obtained otherwise thanks to supply  601 . 
     Filling of the reservoir  8  is controlled thanks, for example, to an encoder  604  connected to the rod  8   a  of the piston  8   b  of the reservoir  8 . In effect, the displacement of the rod  8   a  is proportional to the quantity of product introduced in the reservoir  8 . 
     The invention has been illustrated when the sub-assembly  7  is cleaned and filled. It is, of course, used when cleaning and filling the sub-assembly  7 ′ while sub-assembly  7  is used for coating a body  3 , the area  12  of the carriage  20  in that case being brought opposite the unit  51  then displaced by the table  21  up to its position of connection of the sub-assembly  7 ′ with the units  51  and  52 . 
     The order of the sequences of the process of the invention may be modified with respect to what has been described hereinbefore. However, the mobile part  529  of the unit  52  is preferably positioned, in the movement represented by arrow F 6 , to bring the appropriate module  521  or  524  to the level of the median axis of the axis X 10  before the table  21  is displaced in the direction of arrow F 3  since a control unit of the station  10  makes it possible to anticipate knowing the coating product having to be used in a subsequent step of filling a sub-assembly  7  or  7 ′. 
     When a module  7  or  7 ′ has been cleaned and filled, the table  21  is re-introduced into the booth C, through the opening  5   a  of the partition  5 , which allows another sub-assembly to be deposited in the free area  11  or  12  and the module ready to paint to be taken by the robot  1 . 
     The fact that the main part of the station  10  is installed outside the booth and that the cleaning and filling operations take place outside the booth, avoids the table  21  and the connection surfaces of the sub-assemblies  7  and  7 ′ being soiled by the deposit of particles of paint not deposited on a body  3 . This also facilitates maintenance of the station  10  during production. 
     According to a variant of the invention (not shown), the station  10  may be installed in a recess provided in the partition  5  and facing the interior of the spray booth. In that sense, the station  10  is located in the booth, but, for the main part, outside the area of activity of the robot  1 . The table  21  is in that case displaced, perpendicularly to the axis of conveyance X—X′, between a position where it is accessible by the robot  1 , for the operations of deposit of a sub-assembly  7  or  7 ′ in the corresponding area  11  or  12  and of connection of another assembly on the segment  6   c , and a position inside the recess, i.e. outside the range of the robot, where the operations of connection, cleaning and/or filling take place. This recess may be accessible from outside the booth by means of doors or traps, which allows interventions on the station  10  while a body  3  is being coated 
     The invention has been described with rotary sprayers  9  and  9 ′. However, it is applicable with pneumatic sprayers which may or may not be electrostatic. A station  10  of “mixed” type may be envisaged, adapted to receive sub-assemblies comprising both rotary and pneumatic sprayers. 
     Where the spray cycle time is shorter than the cleaning/filling cycle time, two cleaning/filling stations may be provided in the vicinity of a robot. Where the spray cycle time is more than twice the cleaning/filling cycle time, one cleaning/filling station may be provided for two adjacent robots, such a station in that case forming at least three sub-assembly receiving areas.