Abstract:
A steering column switch having a switch element and a switch lever, wherein the switch lever is designed from first and second modules. Because of the modular design, different grip pieces can be accommodated by the same switch element.

Description:
TECHNICAL FIELD 
   The invention generally relates to electrical switches and more particularly relates to steering column switches of a vehicle. 
   BACKGROUND OF THE INVENTION 
   EP-A-0 845 389 discloses a steering column switch with a housing, in which at least one operating lever is mounted to pivot and/or move, for which different types of operating levers with the corresponding contact device can be used during assembly. A mating contact device with a predefined number of switch functions that cooperates with the contact device of the operating lever is arranged in the housing of the steering column switch. The available choice of switch functions is a function of the type of operating lever to be installed and its contact device. 
   DE-A-43 32 748 also shows a steering column switch with a switch lever mounted to move, at least in one plane relative to the steering column, in a housing, which is in connection with switch elements arranged on a printed-circuit board for its activation. At least one of its switch elements is designed as a light-transmitting or light-receiving element in optical connection with a corresponding optical switch, operable by the switch lever. 
   DE 44 28 883 C1 discloses a steering column switch with a housing having mounts for single switches. The single switches comprise a switch housing, in which a switch lever is mounted to pivot. Guide elements are molded onto the switch housing for alignment in the correct position and holding in a mounting chamber of the housing. The switch housing also has clip elements for fastening of the switch in the corresponding mounting chambers. The switch is provided with function elements and is equipped with a printed-circuit board that is connected to a central circuit board of the steering column switch. 
   Steering column switches are also known, whose switches, integrated in a switch lever, are connected by corresponding wiring to a circuit board of the steering column switch, on which the switch lever is mounted in a two-part housing of the steering column switch, whose separation runs in the region of the switch lever. This type of switch lever must have corresponding free space available in its interior, in order to permit passage of the wiring, which requires relatively large dimensioning of the switch lever. Significant assembly expense is required for wiring within the switch lever, as well as from the switch lever to the corresponding circuit board. The steering column switches are pre-mounted together with the corresponding switch lever and then installed in the vehicle, so that a significant risk of damage to the switch lever exists during handling of the steering column switches. 
   The object of the invention is to devise a steering column switch of the initially mentioned type, which has various applications, in terms of functions, is inexpensive to manufacture and easy to handle during assembly. 
   The objective is realized according to the invention in that the switch lever is assembled from a foot cooperating with the switch element and a grip piece inserted into the foot. 
   Because of the two-part design of the switch lever, the switch mechanics of the steering column switch can be made cost effectively in a large number of pieces, regardless of its switching functions. Coordination of the switching functions to the steering column switch, provided with a central printed-circuit board, occurs by means of corresponding programming of the computer system of the vehicle. More specifically, the switch lever (grip piece) is coupled to the foot of the switch lever. Insertion of the grip piece into the foot can occur at the end of assembly of the steering column switch in the vehicle, for which reason the grip piece is only exposed to limited risk of damage during assembly. In addition, the arrangement of a one-part housing for the steering column switch is possible, which need only be provided with a corresponding opening for the grip piece. A visually pleasing effect is achieved with the one-part housing. 
   In a steering column switch of the initially mentioned type, with at least one additional switch integrated in the switch lever of the single switch, the objective according to the invention is realized in that the switch lever is assembled from a foot cooperating with the switch element and a grip piece inserted into the foot, wherein the end of the grip piece inserted into the foot has contact traces, which transmit the functions of the switch to the terminal contacts via a contact unit. 
   Because of these advantages, prefabrication of the switch mechanism of the steering column switch, together with the contact unit and the foot of the switch lever, is ensured in a relatively large number of pieces. Different grip pieces, insertable into the foot of the switch lever, each can be equipped with at least one arbitrarily designed switch. For example, a switch for interval functions of the windshield wiper is connected to the grip piece for a windshield wiper/washer switch. In addition or as an alternative, a switch to control a computer system is provided, in which the switch or switches cooperate with the contact traces integrated in the grip piece, and the electrical connection to the terminal contacts for the switch or switches is achieved by simple insertion of the grip piece into the foot over the contact unit. 
   In order to achieve rapid, permanent assembly, and also several degrees of freedom of the switch lever, the foot of the switch lever is preferably mounted as a swivel joint and provided with two opposite clip arms that engage in corresponding clip openings of the grip piece. 
   For simple swivel mounting of the switch lever and to achieve switching functions, the foot of the switch lever is expediently mounted to pivot in an opening of an arm of an L-shaped rotary switch element, where the rotary switch element is inserted into an arm of a Z-shaped support fixed to the housing. Arrangement of additional mounts with a switch lever therefore is unnecessary, since corresponding support sites are integrated in the rotary switch element. 
   The arm of the rotary switch element running parallel to the connector of the support is preferably provided with a terminating locating curved element that cooperates with a spring-loaded locating sleeve in the arm of the support facing the end of the rotary switch element. Thus, an initial position of the swivel-mounted switch lever is defined and a desired switching sensation is created during its operation. The arm of the support carrying the locating sleeve for the rotary switching element expediently comprises an additional spring-loaded locating sleeve that cooperates with a locating curve in the free end of the foot. Thus, the switch lever is held in a certain initial position. Pivoting of the switch lever from the initial position occurs against the spring force, to which the locating sleeve is exposed, so that a corresponding switch sensation is produced. 
   According to an advantageous modification of the invention, the arm of the support carrying the locating sleeves supports a sliding switch element, acted upon by the foot of the switch lever. The support therefore represents an essential component to accommodate the sliding switch element, as well as the rotary switch element, and forms a separate assembly with the connected switch element, which is simple to install and replace. 
   The switch contacts of the rotary switch element and the sliding switch element are expediently designed as contact springs and act on corresponding contact traces of the support that are connected to the terminal contacts. The contact springs are components of a punched grid inserted into the rotary switch element and the sliding switch element, which is simultaneously injection molded during production of the switch elements in the injection molding process, so that an additional assembly step can be eliminated. In order to avoid damage to the grip piece and the foot during assembly, the grip piece has a centering shoulder on the end inserted into the foot, which engages in a corresponding centering hole of the foot. 
   According to an advantageous embodiment of the concept of the invention, the contact traces of the grip piece are exposed regions of a punched grid integrated in the grip piece connected to the switch. Relatively costly wiring of the switch with the contact traces is therefore eliminated and a number of switching functions to be transmitted are possible by appropriate coding of the punched grid introduced to the grip piece. 
   In order to produce a cost-effective contact unit having relatively high functional safety and that ensures tolerance and movement compensation, the contact unit preferably has contact arms designed as leaf springs, where one end of each contact arm is connected to the corresponding contact trace of the punched grid of the grip piece and the other end of the contact arm is connected to a corresponding contact trace of the support. The contact arms of the contact unit that act on the contact traces of the support extend through a recess of the rotary switch element mounted in the support. 
   According to a modification of the invention, the contact unit has limiting arms on the side that extend essentially parallel to the contact arms. Each arm of the contact unit has a cylindrical shoulder on the end, where the opposite shoulders on one end of the contact unit engage in a corresponding recess of the rotary switch element and the shoulders on the other end of the contact unit engage in a corresponding recess of the foot. The contact unit therefore represents a compact assembly that can be fixed relatively simply between the rotary switch unit and the foot. 
   The recesses in the rotary switch element, in which the shoulders of the arm of the contact unit engage, are, advantageously, cylindrical holes. The recesses in the foot of the switch lever, into which the shoulders of the arm of the contact unit engage, are also elongated holes. In this way, a compensatory movement of the contact unit is guaranteed during the pivoting of the switch lever to act on the sliding switch element. The sliding of the contact arms of the contact unit on the corresponding contact traces of the grip piece and the contact traces of the support effects the self-cleaning of the support. 
   It is understood that the aforementioned features and those still to be explained can be used not only in the stated combination, but also in other combinations without departing from the scope of the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows an exploded view of a steering column switch according to the invention; 
       FIG. 2  shows an enlarged view of a detail II according to  FIG. 1 ; 
       FIG. 3  shows a view in the direction of arrow III according to  FIG. 2 ; 
       FIG. 4  shows an exploded view of a detail II according to  FIG. 1 ; and 
       FIG. 5  shows another exploded view of a detail II according to FIG.  1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Now referring to  FIG. 1 , the steering column switch comprises a housing  1  that consists of a cover  2  and a support module  3 , and an individual switch  6  designed as a blinker switch  4  and a wiper/washer switch  5 , as well as a circuit board  7 . On the side facing the steering wheel (not shown), a transfer element  8  to control the functions of an airbag in cover  2  of housing  1  is inserted, which is connected to circuit board  7 . The cover  2  is provided with clip openings  9  on its periphery that engage with corresponding clip arms  10  of support module  3 . The support module  3  also contains a mount  11  for an ignition key and a fastening device  12  to attach the steering column switch to a jacket tube of a steering column of the vehicle. 
   The blinker switch  4  and the wiper/washer switch  5  are designed identically, and each consists essentially of a support  13  with terminal contacts  14  that engage in corresponding holes  15  of circuit board  7 , a rotary  16  and sliding switch element  17  and a swivel-mounted switch lever  18 . The switch lever  18  is designed in two parts and consists of a foot  19  and a grip piece  20 . 
   The support  13  is designed essentially Z-shaped and holds, in the arm  21  facing switch lever  18 , two superimposed, spring-loaded, locating sleeves  22 ,  23  in the center, which are components of the locating elements  24  of the corresponding single switch  6 . For this purpose, a dome  25  is molded onto the arm  21  of support  13 , into which corresponding compression springs  26  are inserted that act on locating sleeves  22 ,  23 . The arm  21  also has opposite grooves  27  to guide the sliding switch element  17 , as well as contact traces  61 . 
   The second arm  28  of support  13 , designed as a centering shoulder, is fixed in the support module  3  of housing  1  in a corresponding recess  29 . The connector  30  that connects arms  21 ,  28  comprises a mounting hole  31  inserted into the centering shoulder in the region of arm  28  to support the rotary switch element  16 . 
   The essentially L-shaped rotary switch element  16  has switch contacts  33  assigned to the long arm  32 , which are designed as contact springs and cooperate with contract traces  34  in connector  30  of support  13 . The switch contacts  33  extend into a recess  35  of arm  32  and are provided on their free end with a V-shaped angle  36 , the point of which acts on the corresponding contact trace  34 . An additional recess  37  is provided in arm  32  of the rotary switch element  16 , parallel to the recess  35  for the switch contacts  33 . A locating curve  60  is introduced to the end of the arm  32  of rotary switch element  16 , which cooperates with the locating sleeve  23  of support  13 . 
   The short arm  38  of the rotary switch element  16  contains a bearing pin  40 , formed on the ends and on the opposite side, in which the end bearing pin  40  engages in a corresponding bearing hole in cover  2  of housing  1  and the opposite bearing pin  40  engages in the bearing hole  31  of support  13 . An opening  39  is formed in the short arm  38 , into which the foot  19  of switch lever  18  is inserted to pivot. For this purpose, foot  19  has axial pins  41  on the side that are mounted in corresponding holes  42  of arm  38 . 
   The foot  19  of switch lever  18  also contains a V-shaped, locating curve  43  on its free end facing arm  21  of support  13 , which cooperates with the upper locating sleeve  22 , as well as an operating shoulder  44  that limits the locating curve  43  that acts on the sliding switch element  17 . By cooperation of the locating sleeve  22  with the locating curve  43  of switch lever  18 , it is held in a center position, so that the sliding switch element  17  assumes an equivalent position. The switch contacts  59  that cooperate with the contact traces  61  in arm  21  of support  13  are connected to sliding switch element  17 . 
   A blind hole  46  with a rectangular cross section to accommodate the grip piece  20  is inserted in the longitudinal axis  45  of foot  19  of switch lever  18 . The side walls of the blind hole  46  are formed in areas by two opposite clip arms  47  that engage in corresponding clip openings  48  of grip piece  20 . 
   The grip piece  20  of the single switch  6 , designed as a blinker switch  4 , is provided with an additional switch  49  that serves as a push-button to control a computer system (not shown). For electrical contact transmission, a punched grid is integrated with the switch  49  in the grip piece  20 , having exposed contact traces  50  in the end region inserted into foot  19 . In the region of contact traces  50 , the foot  19  has a perforation  58 , penetrated by contact arms  51  of a contact unit  52 , in which the contact arms  51 , on the one hand, are connected to contact traces  50  of the punched grid of grip piece  20  and, on the other hand, pass through the recess  37  of the rotary switch element  16 , and are connected to corresponding contact traces  53  of support  13 . 
   Arms  54  are arranged parallel to contact arms  51  of the contact unit  52  for fastening of the contact unit on the foot  19  and on the rotary switch element  16 . For this purpose, each arm  54  has a cylindrical shoulder  55  on the end, in which the opposite shoulders  55  on one end of the contact unit  52  engage in corresponding holes  56  of the rotary switch element  16 , and the shoulders  55  on the other end of the contact unit  52  engage in corresponding elongated holes  57  of foot  19 . The required freedom of movement of the switch lever  18  is guaranteed by this mounting of the contact unit  52  with simultaneously ensured transfer of the functions of switch  49 . 
   After switch  49  is acted upon in any position of the switch lever  18  of the corresponding single switch  6 , the transfer of the switch signal occurs via punched grids integrated in the grip piece  20  and its exposed contact traces  50  to one end of the contact arms  51  of the contact unit  52 . The connection to the contact traces  53  of support  13 , and thus to the terminal contacts  14  coupled to the contact traces  53 , is produced via the contact arms  51 . The terminal contacts  14  again contact the circuit board  7  connected to the electrical system. To transmit complex switching functions or for assignment of switching functions to the corresponding single switch  6 , the punched grid of grip piece  20  can be coded, in which transmission occurs according to the coded signals. 
   LIST OF REFERENCE NUMBERS 
   
       
         1  Housing 
         2  Cover 
         3  Support module 
         4  Blinker switch 
         5  Wiper/washer switch 
         6  Single switch 
         7  Circuit board 
         8  Transmission element 
         9  Clip opening 
         10  Clip arm 
         11  Mount 
         12  Fastening device 
         13  Support 
         14  Terminal contact 
         15  Hole 
         16  Rotary switch element 
         17  Sliding switch element 
         18  Switch lever 
         19  Foot 
         20  Grip piece 
         21  Arm 
         22  Locating sleeve 
         23  Locating sleeve 
         24  Locating elements 
         25  Dome 
         26  Compression springs 
         27  Groove 
         28  Arm 
         29  Recess 
         30  Connector 
         31  Bearing hole 
         32  Arm 
         33  Switch contact 
         34  Contact trace 
         35  Recess 
         36  Angle 
         37  Recess 
         38  Arm 
         39  Opening 
         40  Bearing pin 
         41  Axial pin 
         42  Hole 
         43  Locating curve 
         44  Operating shoulder 
         45  Longitudinal axis 
         46  Blind hole 
         47  Clip arm 
         48  Clip opening 
         49  Switch 
         50  Contact trace 
         51  Contact arm 
         52  Contact unit 
         53  Contact trace 
         54  Arm 
         55  Shoulder 
         56  Hole 
         57  Elongated hole 
         58  Perforation 
         59  Switch contact 
         60  Locating curve 
         61  Contact trace