Abstract:
A spray-gun line-connecting device is provided for the connection of a plurality of lines between a robotic arm and a spray device. The spray-gun line-connecting device may provide a plurality of cylindrical connection joints at an interface between mating surfaces. For example, the lines may include enlarged cylindrical heads, which fit within cylindrical receptacles in a first mating surface. A second mating surface may extend over the first mating surface, and include passages aligned with the lines.

Description:
This application claims priority to PCT Application No. PCT/EP2008/053179 entitled “Spray-Gun Line-Connecting Device”, filed on Mar. 17, 2008, which is herein incorporated by reference in its entirety, and which claims priority to German Patent Application No. DE 10 2007 014 216.3, entitled “Spray-Gun Line-Connecting Device”, filed on Mar. 24, 2007, which is herein incorporated by reference in its entirety. 
     BACKGROUND 
     The invention relates to a spray-gun line-connecting device. 
     Spray guns of this type are used for spray-coating articles with liquid paint or liquid lacquer. 
     Spray guns of this type are known, for example, from EP 1 287 901 B1. 
     BRIEF DESCRIPTION 
     The invention is intended to achieve the object of improving the line-connecting device between a robot arm and at least one spray gun held by the robot arm. 
     According to the invention, a perforated plate can achieve the following advantages: good protection of the tube connecting sockets against mechanical damage and dirt; inexpensive and good sealing, preferably by means of O rings, on the rear and front sides of the perforated plate for supplying liquid paint or liquid lacquer and one or more airflows from the bundle of tubes in the robot arm to at least one spray gun held by the robot arm. 
     The dependent claims contain further features of the invention. 
     Exact positioning of the seals is achieved in a simple manner by arranging, according to the invention, seals in depressions, e.g. annular grooves or bore steps, in the perforated plate. 
     The fastening of the perforated plate to a robot flange or to the robot arm, according to the invention, prevents the perforated plate from being lost even when no spray gun is fastened to the robot arm. 
     A spray gun or an intermediate element, which can be used to connect one or more spray guns to the robot arm, may be fastened to the robot arm, to the robot flange or to the perforated plate depending on the expediency in the practical use of the invention. 
     According to one particular embodiment of the invention, the socket collars of tube connecting sockets are provided with a circular outer circumference rather than with a polygonal, for example hexagonal, outer circumference, as is the case in the prior art. Smaller distances are thereby possible between the flange holes and therefore also between the tubes. The circular shape of the socket collars makes it easier to install and remove the tubes since the radially protruding socket collars can be positioned in any desired direction of rotation without colliding with adjacent socket collars. This also makes it possible to use larger dimensional tolerances. 
    
    
     
       DRAWINGS 
       In the text which follows, the invention is described with reference to the appended drawings and on the basis of a preferred embodiment as an example. In the drawings: 
         FIG. 1  shows a perspective illustration of an automatic spray gun which is fastened to a robot arm, 
         FIG. 2  shows a perspective exploded illustration of the end portion of the robot arm with a bundle of tubes, which extends out from said end portion, and a perforated plate, 
         FIG. 3  shows a perspective view of the front end of the robot arm with the perforated plate which is fastened thereto and covers the ends of the tubes which have been pushed back into the robot arm, 
         FIG. 4  shows a view of the front end of the robot arm shown in  FIG. 3 , 
         FIG. 5  shows a cut-off longitudinal section of the robot arm in the radial plane V-V from  FIG. 4 , and 
         FIG. 6  shows an end portion of a tube shown in  FIG. 2  having a tube connecting socket which is pushed onto said end portion and is connected to the tube, for example is clamped to the tube. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an automatic spray gun  2  for spray-coating articles with liquid paint or lacquer. The spray gun  2  is fastened to an adaptor  6  via an intermediate plate  4 , said adaptor having an adaptor flange  8 . Screws (not shown) are used to fasten the adaptor flange  8  to a robot flange  10  which may have one or more parts and is fastened to a tubular end portion of a robot arm  14  by means of screws  12 . A multiplicity of tubes  20  which extend through the robot arm  14  are required in order to supply the spray gun with liquid paint or liquid lacquer and with one or more airflows, for example an airflow for spraying the paint or the lacquer and/or an airflow for shaping the sprayed jet of liquid and/or an airflow for actuating a valve which controls the paint or the lacquer. 
     According to the invention, a new device is provided for the connection of the multiplicity of tubes  20  to the end of the tubular robot arm  14  with bores  26  in the adaptor  6 . The adaptor  6  is an intermediate element in a mechanical connection which, in the embodiment shown, comprises the adaptor  6  and the intermediate plate  4 . According to another embodiment, only a single intermediate element could be provided instead of the adaptor  6  and the intermediate plate  4  or both the intermediate plate  4  and the adaptor  6  could be omitted and the spray gun  2  could be fastened directly to the robot flange  10 ; in the latter case, a housing of the spray gun  2  itself is used as the intermediate element between the tubes  20  of the robot arm  14  and the internal lines of the spray gun  2 . 
       FIGS. 2 to 5  show that the robot flange  10  is provided with a multiplicity of flange holes  30 , in each of which there is inserted a tube connecting socket  32 , which is respectively pushed together with the end of one of the tubes  20  and respectively lies with a radially protruding socket collar  34  against the front flange face  36 .  FIG. 5 , in particular, shows that the robot flange  10  may be formed from a plurality of parts and may have, for example, a single-part or multi-part flange ring  10 - 1  and a flange plate  10 - 2  which is fastened to the flange ring  10 - 1  and arranged centrally with respect thereto. The flange holes  30  are formed in the flange plate  10 - 2  and the front flange face  36 , against which the protruding socket collars  34  lie, is in each case a forwardly pointing bore step of a bore extension of the flange holes  30 . The protruding socket collars  34  of the tube connecting sockets  32  are each completely recessed into the bore extension at the end of the flange holes  30 . 
     The forwardly pointing end side of the flange plate  10  is provided with a depression  38  which is preferably cylindrical and has a forwardly pointing bottom face  40 . The socket collars  34  are recessed into the bottom face  40  such that they do not protrude forward out of the bottom face but rather preferably end in line with it. 
     According to the invention, a perforated plate  42  is arranged in the depression  38  and is preferably in line with the forwardly pointing end face  44  of the flange plate  10 - 2  in the radial direction. 
     The perforated plate  42  extends radially over the socket collars  34  of all the tube connecting sockets  32 . A multiplicity of through-holes  46  are formed in the perforated plate  42  and are arranged axially in line with at least some of the flange holes  30  and therefore also with the channels of the tubes  20  and also with the adjacent ends of the bores  26  in the adaptor  6 . 
     At both ends of the through-holes  46  of the perforated plate  42 , there is respectively arranged an annular seal  48  or  50 , which surrounds the through-hole  46  concerned. 
     The seals  48  on the rear plate side respectively lie or, when the line-connecting device is in the disassembled state, are arranged in such a way that they can be laid, in a sealing manner against a front end face  52  of a tube connecting socket  32 . 
     The seals  50  on the front flange side respectively lie in a sealing manner against a rear end wall  54  of the adaptor  6  ( FIG. 1 ), wherein each seal  50  in each case surrounds the end of one of the bores  26  formed in the adaptor  6  in a sealing manner. 
     The seals  48  and  50  are preferably inserted into annular depressions  49  and  51  in the perforated plate  42 , from which depressions they axially protrude slightly out of the perforated plate  42 , at least when the line-connecting device is in the disassembled state. 
     The perforated plate  42  is fastened in threaded bores  62  of the flange plate  10 - 2  by means of screws  60 . 
     The flange plate  10 - 2  is fastened to the flange ring  10 , for example by means of screws  66 . 
     As shown in  FIG. 2 , the tubes  20  may be pulled out forwards through the flange holes  30 , then provided with the tube connecting sockets  32  at their ends, and then pushed back into the robot arm  14  again, the flange connecting sockets  32  being inserted into the flange holes  30 .