Patent Publication Number: US-9890996-B2

Title: System for tempering vehicle bodies

Description:
RELATED APPLICATIONS 
     This application claims the filing benefit of International Patent Application No. PCT/EP2012/000536, filed Feb. 7, 2012, which claims the filing benefit of German Patent Application No. 10 2011 011 898.5 filed Feb. 21, 2011, the contents of both of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a device for tempering motor vehicle bodies, in particular for drying coated motor vehicle bodies, having
     a) a housing;   b) a tempering tunnel accommodated in the housing for receiving the motor vehicle body;   c) at least one pressure chamber accommodated in the housing and separated from the tempering tunnel by a wall;   d) a plurality of nozzles in the wall;   e) an air tempering unit, which introduces tempered air into the pressure chamber in such a manner that it is able to flow through the nozzles into the tempering tunnel and act upon the motor vehicle body therein.   

     BACKGROUND OF THE INVENTION 
     “Motor vehicle body” is here understood as meaning not only the complete motor vehicle body but also those large parts of such a body in which the problems described below occur in the same manner. 
     When the “tempering” of a motor vehicle body is mentioned herein, it is intended to mean the bringing about of a specific temperature of the motor vehicle body that it initially does not possess. It can be a temperature increase or a temperature reduction. “Tempered air” is understood as being air that has the temperature required for the tempering of the motor vehicle body. 
     A case of the tempering, namely the heating, of motor vehicle bodies that occurs frequently in the automotive industry is the operation of drying the coating of a motor vehicle body, whether the coating be a paint or an adhesive or the like. The following detailed description of the invention is given using the example of such a drier. 
     When “drying” is mentioned herein, it is intended to mean any operation in which the coating of a motor vehicle body, in particular a paint, can be made to cure, either by expelling solvents or by crosslinking the coating substance. 
     Known devices of the type mentioned at the beginning that are configured as driers conventionally possess a pressure chamber on both sides of the tempering tunnel, which in this case is referred to as the drying tunnel. The nozzles, which are accommodated in the walls separating the pressure chambers from the drying tunnel, normally have the same construction, in particular the same projection distance, and differ at most in their orientation, that is to say in the direction of projection; this is chosen in each case so that it is aimed at specific surface regions of the motor vehicle body that is to be dried. All the nozzles in effect act only upon the outer surface of the motor vehicle body. If the air streams emerging therefrom also pass through openings into the inside of the motor vehicle body, they have no appreciable effect there owing to their short reach, especially since two such nozzles generally face one another with opposing flow directions and thus mutually compensate for the action in the interior. 
     Motor vehicle bodies have recently become increasingly more complex in their construction. In particular, they have different masses in different regions. For example, the lowermost region, the sill region or the floor assembly, has a high mass and consequently possesses a considerable heat capacity. Heating of the different regions of the motor vehicle body that is carried out from only one side requires a not inconsiderable time until the heat has penetrated those regions completely. In addition, that time differs locally according to the mass distribution and the distribution of the heat capacities in the region in question. The dwell time of the motor vehicle body that is to be dried in the drier must therefore be adapted to the longest time that is required for drying of the region of the motor vehicle body that is least favourable and has the greatest mass. Not only are the cycle times of the drier increased as a result; overheating can additionally occur in those regions of the motor vehicle body that dry more quickly. This can be particularly disadvantageous where different materials, including heat-sensitive materials, have been used in the motor vehicle body and/or adhesive bonds have been produced. 
     An object of the present invention is to configure a device of the type mentioned at the beginning in such a manner that shorter cycle times can be achieved. 
     SUMMARY OF THE INVENTION 
     The object may be achieved according to the invention in that
     f) there is provided at least one nozzle unit which is so oriented and the distance of projection of which is so great that the air stream leaving it is able to pass through an opening in the motor vehicle body on the side facing the nozzle unit and act upon the inner surface of the motor vehicle on the opposite side.   

     According to the invention, therefore, the concept hitherto applied throughout of exposing the motor vehicle body to tempered air from only one side, namely from the outside, is abandoned. Instead, a tempered air stream is purposively produced by at least one nozzle unit, which air stream passes through an opening on the side of the motor vehicle body facing the nozzle unit and then acts upon the inner surface of the opposite wall of the motor vehicle body. This can also take place from opposite sides of the motor vehicle body. In this manner, tempering of the motor vehicle body takes place both from outside and from inside, which is naturally accompanied by a significant shortening of the tempering time. 
     In a particularly preferred embodiment of the invention, at least one nozzle unit has movable air guiding elements, so that the direction of projection of the nozzle unit is adjustable. 
     Motor vehicle bodies of different geometries and constructions can be guided through such a device; the tempering action can be adapted to the specific construction by adjusting the direction of projection of the nozzle unit. In the case where the system is operated by type, that is to say where motor vehicle bodies of the same type are always dried, adjustment of the air guiding elements can take place manually. 
     It is particularly advantageous if the air guiding elements are movable by means of a motor. No manual intervention is then required to adjust the air guiding elements. The type of motor vehicle body being treated in a particular case can be detected automatically, and the position of the air guiding elements can be adjusted automatically in the required manner by a corresponding control device. In this manner it is also possible to move the air guiding elements continuously with the motor vehicle body in such a manner that the tempered air stream leaving the corresponding nozzle unit follows the motor vehicle body as it passes through the tempering tunnel. Longer times for exposure of a particular location on the motor vehicle body can thus be achieved without lengthening the cycle time. 
     It is also possible for the air guiding elements to be movable by a carrier device, which cooperates with a part that is moved together with the motor vehicle body in such a manner that the direction of projection of the nozzle unit follows the motor vehicle body over a certain distance as it moves through the tempering tunnel. In this embodiment, therefore, motor-operated drive elements are not required for the air guiding elements, and sensors that monitor the position and movement of the motor vehicle body, and corresponding control devices, are not required. 
     The embodiment of the drier according to the invention in which the nozzle unit has air guiding elements that are pivotable about two mutually perpendicular axes is particularly variable. 
     The nozzle unit can be removably fixed in at least one opening in the wall between the pressure chamber and the tempering tunnel. In this manner, it can quickly be removed if required, so that it does not interfere with particular work such as cleaning and maintenance, also of the transport system, outside of the actual tempering operation. 
     It is also advantageous if the at least one opening in which the nozzle unit is fixed is configured in the same manner as the openings in which the other, normal nozzles are fixed in the same wall. The nozzle unit can accordingly be retrofitted, for example, to a conventional device by removing one or more of the normal nozzles from the wall between the pressure chamber and the tempering tunnel and instead fixing in that or those openings the nozzle unit according to the invention. Conversely, the removal of a device configured according to the invention from a conventional device is, of course, also possible without difficulty. 
     It is to be understood that the aspects and objects of the present invention described above may be combinable and that other advantages and aspects of the present invention will become apparent upon reading the following, description of the drawings and detailed description of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the invention will be explained in detail below by means of the drawing, in which 
         FIG. 1  shows a vertical section through a drier for drying coated motor vehicle bodies; 
         FIG. 2  shows a horizontal section through the drier of  FIG. 1  according to line II-II therein; 
         FIG. 3  shows horizontal sections, similar to  FIG. 2 , through part of the drier with different nozzle positions; 
         FIG. 4  shows vertical partial sections through two similar modifications of the drier shown in  FIG. 1 ; 
         FIG. 5  shows a carrier mechanism for adjusting a nozzle unit in different positions; 
         FIG. 6  shows a top view of a nozzle outlet in a further exemplary embodiment of a drier; 
         FIG. 7  shows vertical sections through an adjustable nozzle unit in two different positions; 
         FIG. 8  shows a vertical section, similar to  FIG. 7 , with an obliquely fitted nozzle unit; 
         FIG. 9  shows a vertical section, similar to  FIG. 1 , through a further exemplary embodiment of a drier; 
         FIG. 10  shows vertical sections, similar to  FIG. 4 , through a drier having an adjustable nozzle unit in two nozzle positions. 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION 
     While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail one or more embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. 
     Reference will first be made to  FIGS. 1 and 2 . The drier shown here, which is designated generally by the reference numeral  1 , has in known manner a housing  2 , the interior of which is divided by two vertical longitudinal walls  3 ,  4  into two lateral pressure chambers  5 ,  6  and a middle drying tunnel  7 . The motor vehicle bodies  9  to be coated are conveyed through the drying tunnel  7  perpendicular to the plane of the drawing of  FIG. 1  by means of a transport system  8 , which is shown schematically. At the ends of the drying tunnel  7  there are generally provided locks (not shown), which allow the motor vehicle body  9  to pass into and out of the drying tunnel  7  without great heat loss and with a low atmosphere exchange. 
     In the two walls  3 ,  4  there is a plurality of nozzles  10 ,  11 , which establish a connection between the pressure chambers  5  and  6  and the drying tunnel  7 . The nozzles provided with reference numerals  10  and  11  are of conventional configuration; their direction of projection is adjustable and their direction of projection is so short that they are able to act upon the side of the motor vehicle body  9  facing them. The nozzles  10 ,  11  are located in openings  13 ,  14  with spherical-cap-shaped delimiting walls, as a result of which the nozzles  10 ,  11  are guided in an adjustable manner in their angular position. 
     In each of the openings  12   a  and  13   a  in the walls  3 ,  4  that is located in the position second from the top there is no conventional nozzle  10  or  11 . Instead, a special nozzle unit  14  or  15  is fixed therein, which nozzle unit is provided for that purpose with two spherical-cap-shaped clamping plates  16  and  17 . The arrangement is accordingly such that the nozzle units  14 ,  15  can be mounted in the corresponding wall  3 ,  4  in place of a conventional nozzle  10 ,  11 . In this manner, conversion of a conventional drier into a drier  1  according to the invention and vice versa is possible. 
     The nozzle units  14 ,  15  are identical in construction, so that it is sufficient to describe the nozzle opening  14 . This comprises a box-like housing  14   a , which is substantially open on the side facing the motor vehicle body  9  and is provided on its rear side, which abuts the wall  3 , with an opening that communicates via the corresponding opening  12   a  with the pressure chamber  5 . Inside the housing  14   a  there are parallel fins  14   b  as air guiding elements, which in the exemplary embodiment shown in  FIGS. 1 and 2  are built fixedly into the housing  14   a , that is to say are not movable. 
     The particular feature of the nozzle units  14 ,  15  is that, unlike the “normal” nozzles  10 ,  11 , they are in the form of long-range nozzles. In this manner it is possible in the manner shown in  FIGS. 1 and 2  to direct the hot air leaving the nozzle units  14 ,  15 , the circulation of which in the drier  1  will be described in detail below, through an opening in the side face of the motor vehicle body  9  that is facing them, for example through a window opening or through an open door, onto the inner surface of the opposite side of the body, so that the hot air stream thus passes through the whole of the interior of the motor vehicle body  9 . The direction of this hot air is such that it is directed predominantly at the bottom, inner region of the motor vehicle body  9 , where there is a comparatively great mass and therefore a large heat capacity. 
     The pressure chambers  5 ,  6  are fed in known manner with hot air, which then passes not only in the manner already indicated above through the nozzle units  14 ,  15  but also through the normal nozzles  10 ,  11 , so that hot air acts upon the outsides of the motor vehicle body through the normal nozzles  10 ,  11  and upon the insides of the motor vehicle body  9  through the additional nozzle units  14 ,  15 . In this manner it is possible to dry all regions of the motor vehicle body  9  in approximately the same time, even though they are “high-mass” to differing degrees and therefore have different heat capacities. As a result, the total drying time of the motor vehicle body  9  can be shortened; local overheating, which could damage the materials of the motor vehicle body  9  or bonds located thereon, does not occur. 
     As mentioned above, the nozzle units  14 ,  15  of the exemplary embodiment of  FIGS. 1 and 2  are fixed, so that the direction of the hot air stream leaving them is not adjustable. It may, however, be advantageous for that direction to be adjustable, as is shown by means of  FIGS. 3 a  to 3 c    for a modified drier  101 . Where components shown in  FIG. 3  correspond to those of  FIGS. 1 and 2 , they are identified by the same reference numerals plus 100. 
       FIGS. 3 a  to 3 c    are horizontal sections through the modified drier  101 , similar to  FIG. 2 , but each show only a cutout. There can be seen a pressure chamber  105 , the wall  103  which separates the pressure chamber  105  from the drier tunnel  107 , the coated motor vehicle body  109  that is to be dried, and two nozzle units  114 . While the fins  14   b  and  15   b  in the nozzle units  14 ,  15  of  FIGS. 1 and 2  were fixed, in the exemplary embodiment of  FIG. 3  they are pivotable about a vertical axis, but their parallel orientation is retained. The mechanism required therefor is not shown but is known to the person skilled in the art. 
     Partial figures a to c of  FIG. 3  show how the directions of projection of the nozzle units  114  follow the movement of the motor vehicle body  109 . The direction of movement of the motor vehicle body  109  is from left to right. It will be seen how the hot air streams leaving the nozzle units  114  follow the movement of the motor vehicle body  109  and are thus able to act upon the inner surfaces of its side walls for longer than in the case of rigidly oriented fins.  FIG. 3  shows only the nozzle units  114  on one side of the drying tunnel  107 ; the opposite nozzle units (not shown) are, of course, configured in the same way. 
       FIGS. 4 a  and 4 b    show schematically how the directions of projection of the nozzle units  114  of the exemplary embodiment of  FIG. 3  can be changed. In the first exemplary embodiment shown in  FIG. 4 a   , an aperture  120  is provided in the wall  103  beneath a “normal” nozzle  110 , in which aperture a plurality of parallel, sloping fins  114   a  is rigidly fixed. The fins  114   a  specify the inclination of the air stream passing through the aperture  120 , which is so chosen that the air stream, as shown in  FIG. 1 , is able to pass through a window of the motor vehicle body on the side of the body facing it and act upon the opposite body wall on the inside. In front of the aperture  120  on the side of the drying tunnel  107  there is provided a rotary body  121 , which can be rotated by means of an electric motor  123  by way of an actuating rod  122 , which extends vertically upwards and passes through the upper side of the housing  102 . The rotary body  121  contains a plurality of parallel fins (not shown in the drawing), which extend vertically, and the air that has passed through the fins  114   a  in the aperture  120  is able to flow through the gaps between them. Obviously, it is thus possible, by rotating the rotary body  121  with the aid of the electric motor  123 , to change the direction of projection of the nozzle units  114  in a manner shown in  FIG. 3 . 
     The variant of the drier that is shown in  FIG. 4 b    differs from that explained above by means of  FIG. 4 a    only in the following: The actuating rod  122 ′ connected to the rotary body  121 ′ does not extend upwards but perpendicularly downwards, where it is connected not to an electric motor but to a carrier mechanism, which is shown in  FIGS. 5 a  to 5 c   . The lower ends of the actuating rods  122  are rigidly connected to pivot levers  124  projecting into the interior of the drying tunnel  7  and are additionally mounted in bearing brackets  125  fixed to the wall  103 . The free ends of the pivot levers  124  cooperate with pins  126 , which are fixed to the upper side of the skids  127  on which the motor vehicle body is moved through the drying tunnel by means of the transport system. These motor vehicle bodies are not shown in  FIG. 5 . 
     In  FIG. 5 a   , two pins  126  attached to a skid  127  have each reached the outer end of a pivot lever  124 , which is associated with a nozzle unit  114 , which from beneath. As the skid  127  travels further, the pivot levers  124  are pivoted about the bearing in the bearing brackets  125 , as is shown in  FIGS. 5 b  and 5 c   .  5   b  shows an intermediate position, while  FIG. 5 c    shows a position of the skid  127  and the pivot levers  124  shortly before the time at which the ends of the pivot levers  124  come free of the pins  127 . The pivot levers  124  are then returned by spring devices, which are located in the bearing brackets  125 , to the position of  FIG. 5 a    again, where they await the next skid  127  carrying a motor vehicle body. The exemplary embodiment of  FIG. 4 b    with the carrier mechanism shown in  FIG. 5  thus does not require a separate electric motor and the sensors and control devices necessary for the operation thereof. 
     In the exemplary embodiments of a drier according to the invention that have been described above by means of  FIGS. 3 to 5 , the direction of projection of the nozzle units  114 ,  115  was changed only by pivoting about a perpendicular axis, which left the inclination of the air stream flowing through the nozzle units  114 ,  115  relative to the horizontal unchanged. It is, of course, also possible, however, to provide nozzle units which permit rotation of the direction of projection about both the vertical and the horizontal axis. Such a nozzle unit is shown in  FIGS. 6 and 7 . Because it otherwise corresponds functionally to the nozzle unit  14  of  FIG. 1 , it bears the reference numeral  214  here. 
       FIG. 6  shows a top view of the outlet opening of the nozzle unit  214  fitted into the wall  203 . It comprises an inner frame  230  in which there are fixed fins  214   ba  and  214   bb  that extend vertically and horizontally. The fins  214   ba ,  214   bb  can either cross over or be arranged one behind the other when viewed in the flow direction of the air. The inner frame  230  is mounted on gimbals. To that end, it is pivotably connected by way of two horizontally extending axle journals  231  to a central frame  232 , which in turn is connected in an articulated manner by way of two vertically extending axle journals  233  to an outer frame  234 . The outer frame  234  is in turn set into an aperture  220  of an appropriate size in the wall  203 . 
     In  FIG. 7 , the aperture  220  extends perpendicularly through the wall  203 , while in  FIG. 8  the aperture  220 ′ is inclined towards the drying tunnel, which is to be imagined on the right, so that the nozzle unit  214  in  FIG. 8 , while having the same construction, is able to reach a region of the motor vehicle body that is located further towards the bottom than in  FIG. 7 . 
     In  FIG. 7 , no drive mechanisms with which the frames  232  and  234  can be rotated about the respective axle journals  231 ,  233  are shown. The person skilled in the art naturally knows how motor-driven rotation of these frames  232 ,  234  can be carried out. In simple cases in which the direction of projection of the nozzle units  214  needs to be adjusted only rarely, the adjustment of the inner frame  230  relative to the outer frame  234  can also take place manually. 
       FIG. 9  shows a further exemplary embodiment of a drier, which corresponds to the greatest possible extent to that of  FIG. 1 . Corresponding parts in  FIG. 9  are therefore identified with the same reference numerals as in  FIG. 1  plus 300. The fundamental difference between the drier  1  of  FIG. 1  and the drier  301  of  FIG. 9  is that, in the former, the nozzle units  14  and  15  were removably mounted in the walls  3 ,  4  between the pressure chambers  5 ,  6  and the drying tunnel  7 , while in the exemplary embodiment of  FIG. 9  the nozzle units  314  are provided permanently in apertures  320  in the walls  303 ,  304 . Otherwise, the functioning of the drier  301  is wholly identical with that of the drier  1 . 
     Finally, in  FIG. 10 , there is shown, by means of an exemplary embodiment of a drier similar to that of  FIG. 9 , the possibility of pivoting the direction of projection of the nozzles  214  solely about a horizontal axis. To that end, the fins  314   b , which are located in the aperture  320 , are pivotably articulated by their front edges with the side walls of the aperture  320 , while their opposite edges are connected together in an articulated manner by a connecting rod  335  and with a pivot rod  336 . This is guided through the upper side of the housing  302  of the drier  301  and connected to a drive  337 . By axial movement of the pivot rod  336 , it is possible, as will be understood by comparing  FIGS. 10 a  and 10 b   , to change the orientation of the fins  314   b  in the aperture  320  and thus the direction of projection of the nozzle unit  314 , which is formed by the aperture  320  and the fins  314   b  arranged therein. 
     It is to be understood that additional embodiments of the present invention described herein may be contemplated by one of ordinary skill in the art and that the scope of the present invention is not limited to the embodiments disclosed. While specific embodiments of the present invention have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying claims.