Abstract:
A steering switch for vehicles, especially a switch for front and back windscreen wiping/washing switches, including two rotating switches arranged as a distance from each other and integrated into a switch lever, said rotating switches including contact bridges provided with a plurality of contact arms which are respectively secured onto a rotating switch element, and impinge upon the switch contact bridges with associated connecting contacts which are connected to the contacts on the edge of the network.

Description:
TECHNICAL FIELD 
   The invention generally relates to electrical switches and more particularly relates to a steering column switch for motor vehicles. 
   BACKGROUND OF THE INVENTION 
   DE 199 12 087 A1 discloses a steering column switch, which includes a rotary switch for the front wiper functions arranged rotationally symmetrically on a longitudinal axis of a switch lever of the steering column switch. A push-button switch for a front washer function is arranged at the free end of the switch lever. In addition, another rotary switch for the rear wiper/washer functions is arranged on the rotary switch for the front wiper functions. Both the front wiper functions and the rotary switch for the rear wiper/washer functions have a number of contact bridges that corresponds to the number of switch positions, wherein these contact bridges act on corresponding switch contact tracks. The contact bridges and the associated switch contact tracks are shaped like circular segments at the periphery of a rotary switch element of each rotary switch at one end of the rotary switch element. To activate the front washer function, the associated push-button switch is pushed in, wherein the push button also acts on. associated switch contact tracks by way of a corresponding activation plunger that interacts with a contact bridge. The connection of the switch contact tracks to contacts of the vehicle power supply is performed by means of connection lines, which are attached to connection contacts and which are led through the longitudinal axis of the steering column switch. Here, the number of connection lines corresponds to the number of switch contact tracks. For a predetermined number of switch positions, the outer diameter of the switch lever is essentially dependent on the space requirements of the connection lines, particularly in the region of cable bushings between the first and the second rotary switch, wherein the connection lines must feature a certain cross section and insulation. 
   Furthermore, a flexible circuit board is known from DE 198 19 088 A1, which includes a carrier film for conductive tracks and is used as a cable tree for electrical contact of a certain arrangement of electrical and/or electronic components. Such flexible circuit boards are increasingly used as replacements for conventional cable trees consisting of round conductors. The individual conductive tracks are electrically insulated from each other and typically have a rectangular cross section. The top sides of the conductive tracks are electrically insulated by means of a coating or a film. 
   The solved problem of the invention is creating a steering column switch of the initially mentioned type, whose rotary switches are connected to the vehicle power supply with minimal space requirements. 
   According to the invention, the problem is solved such that 
   the connection contacts are connected to the contacts of the vehicle power supply by means of a flexible circuit board, 
   the circuit board has one branch from the connection to the vehicle power supply, wherein this branch divides into two branches, each with a connection, wherein of these two branches, one transitions into another branch with a connection, and 
   the connection of the second branch is associated with one rotary switch and the connections of the third and fourth branches are associated with the other rotary switch. 
   Due to these measures, the space requirements for the electrical connection of the two rotary switches to the vehicle power supply are relatively small, since, on the one hand, the flexible circuit board has a thin structure and, on the other hand, the circuit board is divided into several branches for coupling the rotary switch to the vehicle power supply. Furthermore, the flexibility of the circuit board guarantees high functional reliability of the steering column switch. The circuit board deforms in accordance with the movements of the switch lever as well as the movements caused by the individual rotary switches. In addition, the flexible circuit board is relatively easy to mount by means of simple threads through individual components of the switch lever. The individual branches of the circuit board are manufactured through stamped cut-outs of the circuit board film. 
   The first branch of the circuit board in the flat plane starting from the connection to the vehicle power supply features a first rectilinear region, which transitions by way of an angled section into a second rectilinear region, which is aligned parallel and spatially separated from the first region. The region of the angled section is arranged in the outlet region of the flexible circuit board from the switch lever and, according to corresponding deformation, enables the connection of the connector to the contacts of the vehicle power supply and provides the flexibility required for the pivoting motion of the switch lever. 
   Advantageously, the second rectilinear region of the first branch splits in a plane above the connection to the vehicle power supply into the second and third branches, which are aligned parallel to each other, wherein the second branch carries the connection at the end and the third branch extends in a straight line outwards over a plane of the connection. Furthermore, the third branch transitions into an angled section running in the direction of the connection of the second branch, in which the connection is arranged. Finally, the third branch transitions in the region of its angled section into the fourth branch, which carries the connection on the end. The course of the individual branches of the circuit board corresponds to a cable tree-like structure and can be realized for the production of the circuit board with minimal material consumption. 
   In order to be able to implement the connection of the connectors to the associated connection contacts of the switch contact tracks or the contacts of the vehicle power supply relatively easily, the connection for the vehicle power supply, the connection of the second branch, and the connection of the third branch point in the same direction, and the connection of the fourth branch points in the opposite direction. 
   According to an advantageous refinement of the invention, the connection contacts of the first rotary switch, which is allocated to the free end of the switch lever, are divided into two groups arranged diametrically opposite each other and spatially separated, wherein the first group is connected to the connection of the third branch and the second group is connected to the connection of the fourth branch of the circuit board. Because the connection contacts are provided in two groups, the space requirements for the plurality of connection contacts is extremely small and simultaneously, the functionality of the first rotary switch is guaranteed. 
   So that the connection between the connection contacts and the contacts of the vehicle power supply by means of the flexible circuit board do not have a disruptive effect on the mechanics of the first rotary switch, the fourth branch of the circuit board in the assembled state of the first rotary switch preferably passes to the side of the hinge pin formed on an intermediate ring. 
   In a further configuration of the invention, the fourth branch of the circuit board is deformed essentially in the form of a W due to a crosspiece of the intermediate ring supported to the side of the locking sleeves. This deformation is realized automatically during assembly and must be taken into account only for the length dimensioning of the fourth branch. 
   In order to create a long-lasting electrical connection between the connections and the associated contacts, the connections have contact points that are soldered to the associated connection contacts or to the contacts of the vehicle power supply. 
   The rotary switch element of the first rotary switch preferably features a contact arm to be activated by a push button inserted in the first rotary switch for acting on associated switch contact tracks. Thus, another switch is integrated in the steering column switch. The electrical connection of this switch to the contacts of the vehicle power supply is realized by means of the flexible circuit board without additional space requirements. 
   Advantageously, the switch contact tracks of the first and second rotary switch are structured as an extrusion-coated stamped grid, wherein the switch contact tracks of the first rotary switch are arranged on the hinge pin of the intermediate ring and the switch contact tracks of the second rotary switch are arranged on an axial end of an activation element of the rotary switch. The extrusion-coated stamped grids can be handled easily during the soldering of the connections of the circuit board and during the assembly in the switch lever. 
   It is understood that the features mentioned above and the features still to be explained in the following can be used not only in the indicated combination, but also in other combinations without leaving the scope of the present invention. 

   
     BRIEF DESCRIPTION OF THE INVENTION 
       FIG. 1 , an exploded view of a switch lever of a steering column switch according to the invention, and 
       FIG. 2 , a flexible circuit board of the steering column switch in a flat plane. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A spring-loaded push button  2  for a front washer function is inserted in a switch lever  1  of the steering column switch at the end. This push button is inserted by means of two opposing clip arms  3  so that it can move in corresponding grooves  4  of an activation element  5  of a first rotary switch  6  configured as a front wiper/washer switch. On the side associated with the activation element  5  on the outer periphery of the push button  2 , there is an activation plunger  7 , which projects through a rotary switch element  8  of the first rotary switch  6 . 
   The first rotary switch  6  essentially includes the rotating activation element  5 , in which the rotary switch element  8  is supported locked in rotation. On the peripheral side in the activation element  5 , a lock (not shown) is configured, which interacts with spring-loaded locking sleeves  9 , wherein the locking sleeves  9  are arranged in a crosspiece  10  of an intermediate ring  11  of the switch lever  1 . The interaction of the lock with the locking sleeves  9  creates a secure fixing of the first rotary switch  6  in the desired switch position. The rotary switch element  8  has a contact bridge for the front wiper/washer functions on its end side facing the intermediate ring  11 , wherein only one spring-loaded contact  12  to be activated by the activation plunger  7  of the push button  2  can be seen for the front washer function. The free ends of the contact arms (not shown) point in the direction of the intermediate ring  11  and the free end of the contact arm  12  points in the direction of the activation plunger  7  of the push button  2 . The free ends of the contact arms are arranged such that they interact with switch contact tracks  14  configured as a stamped grid  13  for transmitting the front wiper functions. In order to achieve sufficient stability of the stamped grid  13 , the grid is extrusion coated and supported locked in rotation on a hinge pin  14  of the intermediate ring  11 . For connecting the stamped grid  13  to contacts (not shown) of a vehicle power supply, each of the switch contact tracks  14  is provided with a connection contact  15  pointing in the direction of a foot  15  of the switch lever  16 . 
   On the side of the intermediate ring  11  facing away from the stamped grid  13 , a second rotary switch  17  configured as a rear wiper/washer switch is located with a rotary switch element (not shown), which is arranged in an activation element  18  supported on an axial end of the intermediate ring  11 . On the peripheral side, the activation element  18  supports two locking sleeves  19 , which interact with a lock of the intermediate ring  11 . The switch contact tracks  21  of the second rotary switch  17  configured as an extrusion-coated stamped grid  20 . are supported locked in rotation in a housing  22  of the switch lever  1  and have connection contacts  23 , which extend into the housing  22 . A position centering of the stamped grid  20  is realized, on the one hand, by means of a shaft of the activation element  18 , where this shaft extends through a corresponding hole  24  of the stamped grid  20 , and on the other hand, by means of tabs  25 , which are formed on the stamped grid  20  and which engage in corresponding housing-side grooves  26 . 
   For attaching the first rotary switch  6  and the second rotary switch  17  to the housing  22  of the switch lever  1 , where this housing has a cover  27 , the intermediate ring  11  has clip arms  45  which project through corresponding cut-outs of the activation element  18  of the second rotary switch  17  and interact with locking tabs of the housing  22 . 
   Furthermore, at the foot  15  of the switch lever  1 , carrier axial ends  28  for pivoting support of the switch lever  1  are provided in a steering column switch housing (not shown). 
   For connecting the connection contacts  16  of the switch contact tracks  14  associated with the first rotary switch  6  and the connection contacts  23  of the switch contact tracks  21  associated with the second rotary switch  17  to the contacts of the vehicle power supply, a flexible circuit board  29  is provided, which is illustrated in  FIG. 2  in a flat plane. Starting from a connection  30  for the contacts of the vehicle power supply, a first branch  31  of the circuit board  29  has a first rectilinear region  32 , which transitions via an angled section  33  into a second rectilinear region  34 . The first rectilinear region  32  and the second rectilinear region  34  of the first branch  31  are aligned parallel and spatially separated from each other. In a plane above the connection  30 , the second rectilinear region  34  of the first branch  31  splits into a second branch  35  and a third branch  36 , which are aligned parallel to each other. The second branch  35  carries at its end a connection  37  for connecting to the connection contacts  23  of the switch contact tracks  21  associated with the second rotary switch  17 . The third branch  36  extends outwardly in a straight line over a plane of the connection  37  of the second branch  35  and transitions into an angled section  38  running in the direction of the connection  37  of the second branch  35 . In the angled section  38 , there is a connection  39  for a first group  40  of connection contacts  16  of the switch contact tracks  14  associated with the first rotary switch  6 . Furthermore, the third branch  36  transitions in its angled section  38  into a fourth branch  41 , which carries at its end a connection  42  for a second group of connection contacts  16  of the switch contact tracks  14  associated with the first rotary switch  6 . The connection  30  for the vehicle power supply, the connection  37  of the second branch  35 , and the connection  39  of the third branch  36  point in the same direction, and the connection  42  of the fourth branch  41  points in the opposite direction. Each of the connections  30 ,  37 ,  39 ,  42  have contact points  43 , which are each soldered to the associated connection contacts  16 ,  23  or to the contacts of the vehicle power supply. 
   For the assembly of the switch lever  1 , the third branch  36  and the fourth branch  42  are guided both through cut-outs of the activation element  18  of the second rotary switch  17  and through cut-outs of the intermediate ring  11 , and the contact points  43  of the connections  39 ,  42  are soldered to the associated connection contacts  16  of the switch contact tracks  14  associated with the first rotary switch  6 . For the assembly of the first rotary switch  6 , the stamped grid  13  is set on a hinge pin  44  of the intermediate ring  11  and held by clips of the activation element  5  on the hinge pin  44 . In this way, the fourth branch  41  grips the crosspiece  10  of the intermediate ring  11  such that it deforms into the form of a W. The push button  2  is clipped into the free end of the activation element  5 . Furthermore, the contact points of the connection  37  of the second branch  35  are soldered to the connection contacts  23  of the switch contact tracks  21  associated with the second rotary switch  17 , and the stamped grid  20  is set on the axial end of the activation element  18 . Thus, the first  31 , the second  35 , and the third branch  36  are led through the housing  22  of the switch lever  1  and the housing  22  is closed with the cover  27 . Then the intermediate ring  11  is fixed in the housing  22  by means of its clip arms  45  and the activation element  18  of the second rotary switch  17  is supported between the intermediate ring  11  and the housing  22 . The first branch  31  of the circuit board  29  is led out of the switch lever in the region of the foot  15  of the switch lever  1  from an opening  46  formed between the cover  27  and the housing  22  and connected to the contracts of the vehicle power supply. 
   List of Reference Numbers 
   
       
         1  Switch lever 
         2  Push button 
         3  Clip arm 
         4  Grooves 
         5  Activation element 
         6  First rotary switch 
         7  Activation plunger 
         8  Rotary switch element 
         9  Locking sleeve 
         10  Crosspiece 
         11  Intermediate ring 
         12  Contact arm 
         13  Stamped grid 
         14  Switch contact track 
         15  Foot 
         16  Connection contact 
         17  Second rotary switch 
         18  Activation element 
         19  Locking sleeve 
         20  Stamped grid 
         21  Switch contact track 
         22  Housing 
         23  Connection contact 
         24  Hole 
         25  Tab 
         26  Groove 
         27  Cover 
         28  Carrier axial end 
         29  Circuit board 
         30  Connection 
         31  First branch 
         32  First rectilinear region 
         33  Angled section 
         34  Second rectilinear region 
         35  Second branch 
         36  Third branch 
         37  Connection of  35   
         38  Angled section of  36   
         39  Connection of  36   
         40  Group 
         41  Fourth branch 
         42  Connection of  41   
         43  Contact position 
         44  Hinge pin 
         45  Clip arm 
         46  Opening