Abstract:
A signal distributor for connecting a trunk line to branch lines, includes a plastic housing having a ceiling with passage openings, a printed circuit board with plug sockets for contacting a respective branch line. The plug sockets pass from the rear side of the ceiling through the passage openings during mounting of the circuit board. The outer wall of each plug socket and the outer wall of the passage opening edge are narrowly spaced so that, during casting of a housing cavity that receives the circuit board with a potting compound after installing the circuit board, no potting compound passes through the passage opening. The ceiling and the printed circuit board are made of a first plastic, which has low elongation at break, and the edge of the passage opening is made of a second plastic having an elasticity greater than the elongation at break of the first plastic.

Description:
The present application is a 371 of International application PCT/EP2014/061004, filed May 28, 2014, which claims priority of DE 10 2013 105 518.4, filed May 29, 2013, the priority of these applications is hereby claimed and these applications are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The invention relates to a signal distributor for connecting a signal trunk line to a plurality of signal branch lines, comprising a housing, which is made of plastic and which has a housing ceiling comprising a plurality of regularly arranged passage openings, comprising a printed circuit board, which supports a plurality of plug sockets for contacting a respective signal branch line, wherein the plug sockets pass from the rear side of the housing ceiling through the respective passage openings associated therewith during mounting of the printed circuit board, wherein the outer wall of each plug socket and of the edge of the passage opening associated therewith are narrowly spaced apart from one another such that, during casting of a housing cavity, which receives the printed circuit board, with a potting compound after installing the printed circuit board, no potting compound passes through the passage opening. 
     A signal distributor of the afore-described type is described in EP 1 039 589 B1. The known signal distributor has a housing, which is made of a hard plastic. The housing has the task of connecting a signal trunk line to a plurality of signal branch lines. For this purpose, the signal trunk line can be connected via a plug contact strip to conductor paths on a printed circuit board consisting of hard plastic. The printed circuit board supports a plurality of regularly arranged plug sockets. The housing has a number of passage openings, which corresponds to the number of plug sockets and through which the plug socket can pass when the fully equipped printed circuit board is inserted into a housing cavity. The printed circuit board is thereby inserted into the housing cavity until the plug sockets have passed through the passage openings to the corresponding measure. In this end position, the printed circuit board can lock in place. After that, the housing cavity is cast with a plastic potting compound, which hardens. The gap between the inner edge of the passage opening and the outer edge of the plug socket needs to be minimal, because potting compound can otherwise pass through the gap in response to the casting. Due to the fact that the printed circuit boards and the housing are produced at different production sites, a high tolerance needs to be maintained in response to the production. This increases the price of production or leads to tensions on the printed circuit board, which have the result that electric contacts to the electronic components, which are supported on the printed circuit board, are impacted, respectively, if the tolerances are not maintained. 
     SUMMARY OF THE INVENTION 
     The invention is based on the object of improving the production of the known signal distributor. 
     Initially and substantially it is proposed for the housing ceiling or the housing, which includes the housing ceiling, respectively, and the printed circuit board to be made of a hard plastic. The elongation at break of this plastic is preferably maximally five percent. The plastic can thus also be glass fiber reinforced. The opening has an edge, which is made of a soft plastic, the elasticity of which is preferably at least one hundred percent. As a result, the opening can even be made smaller than specified. The production tolerances can be significantly greater than they need to be estimated in the prior art. The edge of the opening can yield elastically in radial direction. It is sufficient thereby, if the soft plastic component has a radial extension of a few millimeters, in particular between 1 mm and 2 mm. In a preferred embodiment of the invention, the edges of the opening are formed by an annular lining, which is injection molded to the housing ceiling. This preferably takes place in a two-component injection molding process. The Shore hardness of the soft plastic component can be in the range of between 50 A and 70 D. 
     The individual annular linings can be connected to one another by means of webs. The annular linings are preferably mounted to or in the opening, respectively, with a positive fit. For this purpose, the opening of the hard plastic component can embody an annular web, around which the material of the injected soft plastic component wraps. The plastic components furthermore preferably consist of such a material that the surfaces of hard plastic component and soft plastic component connect to one another in an adhesive manner in the area of their bounding surfaces. The soft plastic component can furthermore have a light guiding component. The soft plastic component can furthermore have light guiding sections, which are adjoined by light emitting diodes, which are supported by the printed circuit board so as to be in contact therewith. These light guiding sections are also connected to the annular linings, in particular via webs, so that the annular linings can send light, which is emitted by the light emitting diodes and which is coupled into the light guiding sections. The light emitting diodes are components, which are attached to the top side of the printed circuit board. They are powered by means of conductor paths, which are applied to the printed circuit board. Provision is preferably made for means, by means of which the printed circuit board is fixed to the housing ceiling by means of a force fit. For this purpose, the outer wall of the plug socket can embody a locking step. This locking step overlaps a step of the annular lining. The step of the annular lining can be the edge of the annular lining, which faces the front side of the housing ceiling. The locking step of the plug socket can be formed by an annular collar or an annular groove of the outer wall of the plug socket. The outer wall of the plug socket can in particular be embodied by a sleeve part, which is made of metal. This sleeve part is inserted into a core part of the plug socket, which consists of plastic. Contact pins made of metal, which have fastening feet, are located inside the core part of the plug socket. These fastening feet serve to fasten the plug socket to the printed circuit board by means of soldering. For this purpose, the printed circuit board has openings, through which the solder fastening pins project. The core part of the plug socket can furthermore embody support projections, which are supported on the printed circuit board. The passage openings or the plug sockets, respectively, have a regular arrangement. They can be arranged on the top side of the housing ceiling in rows or in columns, respectively. An arrangement, in the case of which the centers of the passage openings are located on the corner points of a rectangle, are preferred. The totality of the passage openings or plug sockets, respectively, is then located on the corner points of straight lines, which intersect one another at right angles and which are evenly spaced apart from one another, resulting in a plurality of adjacent rectangles having the same design, on the corner points of which an opening or a plug socket, respectively, is located in each case. As a result of tolerances, the length of the sides of the rectangle differ from one another. Fastening sleeves, which, in the installed state, reach through openings of the printed circuit board, can also be made of the soft plastic component. The branch lines have mating plugs, which correspond to the plug sockets and which are attached or screwed to the plug sockets, respectively, so that the leads of a cable, which forms the signal branch line, come into electric conductive connection with the electric contacts. The signal trunk line can be connected to the conductor paths of the printed circuit board via a plug contact. However, provision is also made for the signal trunk line to be embodied by a cable, which is inserted into an opening of the housing, but which is in particular also injected. The plug sockets preferably have a circular cross section. The outer diameter of the plug socket is greater than the inner diameter of the annular lining. The annular lining is thus stretched slightly when the plug socket is pushed through it. The annular lining can thereby deform to varying extents at different circumferential points, so that the annular lining does not only have a tolerance-compensating effect, but also a sealing effect. The annular lining, which has a thickness of between 1 mm and 2 mm, can absorb comparatively high tolerances. It prevents that a potting compound, which is in particular transparent, which is injected into the housing cavity after inserting the printed circuit board, passes past the outer plug socket wall to the front side of the housing ceiling. 
     Exemplary embodiments of the invention will be specified below by means of enclosed drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  shows a perspective illustration of a signal distributor according to the invention, in the case of which no plug sockets  11  are illustrated in two passage openings  5  of a housing ceiling  2 , only for clarification purposes, 
         FIG. 2  shows an illustration according to  FIG. 1 , but completely, 
         FIG. 3  shows a section according to line III-III in  FIG. 2 , 
         FIG. 4  shows the enlarged section IV-IV in  FIG. 3 , 
         FIG. 5  shows the enlarged section V-V in  FIG. 4 , 
         FIG. 6  shows the section according to line VI-VI in  FIG. 2 , 
         FIG. 7  shows a section approximately according to line VII-VII in  FIG. 6 , 
         FIG. 8  shows an exploded illustration for clarifying the embodiment of the different components of the signal distributor, 
         FIG. 9  shows an illustration according to  FIG. 7 , but with a modified soft plastic component  20 , 
         FIG. 10  shows an exploded illustration according to  FIG. 8 , but with the soft plastic component illustrated in  FIG. 9 , 
         FIG. 11  shows an illustration according to  FIG. 5 , but with a step  16 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The drawings illustrate a housing  1 , which consists of a glass fiber reinforced hard plastic. The housing  1  embodies a housing ceiling  2  and housing walls  3 . The rear side of the housing ceiling  2  and the housing walls  3  surround a housing cavity  4 . The housing ceiling  2  has a total of eight regularly arranged passage openings  5 , which has a circular cross section. In addition, the housing ceiling  2  also has a plurality of openings  6 , which serve to display light. The cable of a signal trunk line is injected into an opening  7 . The material of the housing  1  is a brittle, in particular also fiber glass reinforced plastic, which has a small elongation at break. The elongation at break is less than 5 percent. If the material is elongated by more than 5 percent, it breaks. 
     The edge of the passage opening  5 , which is formed by the hard plastic housing ceiling  2 , has an annular web  8 , which is oriented radially inwards. The side wall of the annular web  8 , which faces the front side of the housing ceiling  2 , is narrowly spaced apart from the front side of the housing ceiling  2 . 
     The drawings further show a printed circuit board  10 , which also consists of a fiber glass reinforced hard plastic. This printed circuit board has non-illustrated conductor paths and electronic components, which are connected to the conductor paths by means of a surface contact. In particular, the printed circuit board  10  supports one or a plurality of light emitting diodes  17 . At eight points, which correspond to the locations of the passage opening  5 , the printed circuit board furthermore has fastening openings  15 , which engage with the solder fastening pins  14  of contact pins  13  and which are soldered thereto. The printed circuit board  10  is made of an in particular fiber glass reinforce plastic, which has a high brittleness or hardness, respectively, just as the plastic of the housing  1 , and which has an elongation at break, which is less than 5 percent. 
     The contact pins  13  are inserted into contact openings of a core part  25 , which is made of plastic, of a plug socket  11 . Provision is made for a total of eight plug sockets  11 . 
     The core parts  25  are surrounded by metal sleeves  12 . The metal sleeves  12  are fixedly connected to the core part  25 , in particular with a positive fit. The sleeve parts  12  have a circular cross section and in each case support an annular collar  16 , which projects radially outwards, on their outer wall. 
     The core part  25  embodies feet  18 , by means of which the core part  25  is supported on the top side of the printed circuit board  10 . 
     The drawings furthermore show a soft plastic component  20 , which is injection molded to the housing  1  or the housing ceiling  2 , respectively. This takes place in a two-component injection molding process. The soft plastic component  20  can have light guiding component. It can be transparent. If the soft plastic component  20  is transparent, light, which a light emitting diode  17  couples into a light guiding section  23 , can be guided into the entire soft plastic component  20 . As compared to the hard plastic component, of which the housing  1  or the printed circuit board  10  is made, respectively, the soft plastic component has a significantly higher elongation at break. It is an elastic plastic. In the case of the exemplary embodiment, the elongation at break, thus the elongation, up to which the plastic can be deformed, is at least 100 percent. 
     Annular linings  21 , which reduce the effective inner diameter of the passage openings  5  to such a measure that it is slightly smaller than the outer diameter of the sleeve part  12 , are embodied with the soft plastic component. As a result of the elastic characteristic of the soft plastic component, the annular linings  21  can deform. The wall thickness of the annular lining can thus be reduced area by area by up to 50 percent.  FIG. 1  shows a signal distributor, in the case of which only six of the total of eight passage openings  5  of the housing ceiling  2  are equipped with plug sockets  11 . No plug sockets  11  are illustrated in the two passage openings  5 , which are illustrated on the bottom, for being able to recognize the annular lining  21 . The signal distributor is illustrated completely in  FIG. 2 . The sectional illustration according to  FIG. 3  shows the printed circuit board  10 , which is located in the housing cavity  4 . A space  19 , which is cast with a potting compound  26 , is located between the rear side of the housing ceiling  2  and the surface of the printed circuit board  11 , which faces the housing ceiling  2 . The potting compound  26  also extends across the rear side of the printed circuit board, so that the printed circuit board  10  is cast in completely. 
     It can be gathered from  FIG. 5  that the annular lining  21 , which is embodied by the soft plastic component  20 , is slightly deformed in radial direction. The inner wall of the annular lining  21  rests against the outer jacket wall of the sleeve part  12  at a certain tension. 
       FIG. 11  shows a modification. Here, the outer jacket wall of the sleeve part  12  of the plug socket  11  embodies an annular groove. An outer edge of the annular groove embodies a locking step  16 , against which the outer edge of the annular lining  21 , which faces the outer housing side, rests. 
     The individual annular linings  21  are connected to one another via webs  22 ,  22 ′. In particular  FIGS. 8 and 10  show the type of the connection of the annular linings. In addition, the soft plastic component  20  also embodies the above-mentioned light guiding sections  23 , which have sections, which can project through openings  6  of the housing ceiling  2 . The soft plastic component  20  furthermore also embodies one or a plurality of fastening sleeves  24 , which project away from the rear side of the housing ceiling  2  and which reach through openings of the printed circuit board  10 . 
     As a result of tolerances, the centers of the annular webs  8 , thus of the passage opening  5  embodied by the housing ceiling  2  and the centers of the plug sockets  11 , which are attached to the printed circuit board  10  and which are fixedly connected to the printed circuit board, do not correspond to one another. The annular linings  21  deform, if the printed circuit board  10 , which is equipped with the plug sockets  11 , is inserted into the housing cavity  4 , so that the plug sockets  11 , which project away from the printed circuit board  10 , project through the passage openings  5 . A sealing contact of the annular lining  21  which is made smaller than specified, to the sleeve part  12  thus remains. The printed circuit board  10  is pushed into the opening until the printed circuit board  10  or a light emitting diode  17 , which sits on the printed circuit board  10 , respectively, hits against the bottom side  23 ′ of a light guiding section  23 . As a result of the elasticity of the light guiding section  23 , the printed circuit board  10  can be displaced slightly farther towards the rear side of the housing ceiling  2 , wherein the light guiding section  23  then deforms slightly, so that a secure surface contact of the bottom side  23 ′ against the top side of the light emitting diode  17  is ensured. 
     If the outer wall of the sleeve part  12  has the step  16  as illustrated in  FIG. 11 , the edge section of the annular lining  21 , which faces the front side of the housing ceiling  2 , can support itself thereon. A locking then takes place in response to the insertion of the plug socket  11  in the passage opening  5 . 
     The soft plastic component can consist of an opaque material. However, it can also consist of a translucent material. In the latter case, the light emitted by the light emitting diode  17  can be guided to the outside via the light guiding section  23 . However, the light emitted by the light emitting diode  17  can also be guided to the annular linings  21 , in particular via the webs  22 ,  22 ′, so that the annular linings  21  can send light.  FIG. 6  shows that the soft plastic component  20  forms a conical body, which embodies a light guiding section  23 . The light guiding section  23  has a flat bottom, which rests flat against the light emitting surface of the light emitting diode  17 . The light guiding section  23  projects through an opening  6  of the housing ceiling  2 , so that the light sent by the light emitting diode  17  can pass through the light guiding section  23 . 
     The materials of the hard plastic component, from which the housing  1  is injection molded, and of the soft plastic component  20  are chosen in such a manner that they adhere to one another in the area of their adjacent bounding surfaces, in response to the two-component injection molding. However, provision is additionally made for positive fit holding means for holding in particular the annular linings  21  in the passage openings  5  of the housing ceiling  2  associated therewith. The above-mentioned annular web  8 , the shoulders of which, which are oriented to the bottom and to the top, is insert molded completely by the soft plastic component  20 , so that the annular web  8  engages with a circumferential groove of the annular lining  21 , which has a U-shaped cross section. 
       FIGS. 7 and 8  show a first alternative of the soft plastic component  22 . The soft plastic component  22  forms eight annular linings  21 , which are connected to one another view webs  22 . A plurality of conical bodies, which in each case embody a light guiding section  23 , are located between the two rows of the annular linings  21 . 
     Fastening sleeves  24 , which are embodied by the soft plastic component  20  and which project through the printed circuit board  10  through corresponding openings, can be located between the individual light guiding sections  23 . 
     In the case of the exemplary embodiment illustrated in  FIGS. 9 and 10 , the individual annular linings  21  are connected to one another only by means of webs  22 . The light guiding sections  23  or fastening sleeves  24 , respectively, can be made of other materials. In particular a light guiding plastic component, which does not include any soft plastic components, can be used. 
     The webs  22 ,  22 ′ substantially serve the purpose of ensuring the material flow from the injection pumps to the individual sections of the mold cavity in response to the two-component injection molding. 
     The explanations above serve to specify the inventions, which are captured by the application as a whole and which further develop the prior art independently in each case, at least by the following feature combinations, namely: 
     A signal distributor, which is characterized in that the housing ceiling  2  and the printed circuit board  10  are made of a first plastic, which has a smaller elongation at break, in particular of maximally five percent, and the edge of the passage opening  5  is made of a second plastic, the elongation at break of which is higher than the elongation at break of the first plastic and which is in particular at least one hundred percent. 
     A signal distributor, which is characterized in that the edges of the passage openings  5  are formed by an annular lining  21  of a soft plastic component  20 , which is injection molded to the housing ceiling  2 . 
     A signal distributor, which is characterized in that the Shore hardness of the soft plastic component  20  lies in the range of between 50 A and 70 D. 
     A signal distributor, which is characterized in that the soft plastic component  20  has light guiding components and is in particular transparent. 
     A signal distributor, which is characterized in that the inside dimension of the annular lining  21  is smaller than the outer dimension of the plug socket  11  and that in particular the inner diameter of the circular annular lining  21  is smaller than the outer diameter of the circular plug socket  11 . 
     A signal distributor, which is characterized in that the printed circuit board  10  is fixed to the housing ceiling  2  in a force fit, for the purpose of which in particular a locking step  16  of the plug socket  11  reaches over a step of the annular lining  21 , wherein provision is made in particular for the locking step  16  to be embodied by a circumferential collar or by a circumferential groove of a sleeve part  12 , which is formed by the plug socket  11 . 
     A signal distributor, which is characterized in that the printed circuit board  10  supports electronic components  17 , which are in particular connected to conductor paths of the printed circuit board  10  by means of a surface contact. 
     A signal distributor, which is characterized in that the electronic component comprise at least one light emitting diode  17 , which adjoin a bottom side  23 ′ of a light guiding section  23  of the soft plastic component  20  so as to be in contact therewith, when the printed circuit board ( 10 ) is inserted into the housing cavity ( 4 ). 
     A signal distributor, which is characterized in that the light emitting diode  17  is connected to at least one annular lining  21  via the soft plastic component  20  and in particular via webs  22 ,  22 ′, so that the annular lining  21  sends light emitted by the light emitting diode  17 . 
     A signal distributor, which is characterized in that the plug socket  11  has solder fastening feet  14 , by means of which the plug socket  11  is fastened in openings  15  of the printed circuit board  10 . 
     A signal distributor, which is characterized in that the plug socket  11  has support projections  18 , by means of which it is supported on the top side of the printed circuit board  10 . 
     A signal distributor, which is characterized in that, in the area of a section, which faces the housing cavity  4 , the housing ceiling  2 , which consists of hard plastic, embodies an annular web  8 , around which the outer wall of the annular lining  21  is injection molded in such a manner that the annular lining  21  is tied in the opening of the housing ceiling  2  with a positive fit. 
     All of the disclosed features (alone, but also in combination with one another) are essential for the invention. The disclosure content of the corresponding/enclosed priority documents (copy of the earlier application) is hereby also included in its entirety in the disclosure of the application, also for the purpose of adding features of these documents to claims of the instant application. The features of the subclaims characterize independent inventive further developments of the prior art, in particular for filing divisional applications on the basis of these claims. 
     LIST OF REFERENCE/NUMERALS 
     
         
           1  housing 
           2  housing ceiling 
           3  housing wall 
           4  housing cavity 
           5  passage opening 
           6  opening light display 
           7  opening 
           8  annular web 
           9  signal trunk line 
           10  printed circuit board 
           11  plug socket 
           12  sleeve part 
           13  contact pin 
           14  solder fastening 
           15  fastening opening 
           16  step 
           17  LED 
           18  support projection 
           19  space 
           20  soft plastic component 
           21  annular lining 
           21 ′ inner wall 
           22  web 
           22 ′ web 
           23  light guiding section 
           23 ′ bottom side 
           24  fastening sleeve 
           25  core part