Abstract:
The invention relates to a switch including an operating rocker button and at least one contact element which can be actuated by a radial deflection of the operating rocker button. The contact element can be actuated directly by the operating rocker button, or by the operating rocker button by means of a transmission element. According to the invention, a locking function is provided via a projection on the transmission element or the operating rocker button, which co-operates with an elastic element.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application is a continuation of international application PCT/DE2003/002752, filed on Aug. 18, 2003, which designated the United States and was pending at the time of designation; and further claims priority to German patent applications 10242273.7, filed Sep. 10, 2002, and 10242532.9, filed Sep. 12, 2002, all of which are herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The invention relates to a switch having an operating rocker, in which a contact element can be operated by radial deflection of the operating rocker, and in which the operation of the contact element can be carried out by the operating rocker or by the operating rocker via a transmission element. In the prior art in this case, latching functions are provided by means of metallic lever and/or spring elements, which release a latching and snap-action mechanism.  
       SUMMARY OF THE INVENTION  
       [0003]     The object of the present invention is to describe a switch having an operating rocker and latching functions but with a simpler construction. This object is achieved in that the latching function can be provided by a projection on the operating rocker or on the transmission element interacting with a sprung element. Since the projection can be inserted into the operating rocker or into the transmission element, it is possible to provide both latching and momentary-contact functions with one switch type, depending on whether the projection is or is not inserted. The sprung element has a particularly simple construction by being in the form of part of a switching mat. This means there is no need for any additional element. If the switching mat is formed from rubber or synthetic rubber, for example silicone, this leads to a permanent spring element. The sprung element is particularly functional if it has a structure whose cross section is in the form of waves and/or a sawtooth pattern. If the projection is in the form of a roller, this roller can on the one hand easily overcome the waves or sawteeth during operation of the operating aid, while nevertheless firmly holding the switch in the desired position in the wave troughs of the corrugated structure or in indentations in the sawtooth structure. If the switch has two projections and two contact elements, two switching operations can be carried out with one switch. In this case, if rollers are used as the projections, a latching or momentary-contact function of the switch can be provided depending on whether the roller is or is not inserted. When no rollers are present, a switch can thus be produced with two momentary-contact functions; when one roller is inserted, a switch can be produced with a latching and a momentary-contact function, and when both rollers are inserted, a switch can be produced with two latching functions. If the transmission element is in the form of a light box, this provides an additional function with one component. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0004]     The invention will be explained in more detail in the following text with reference to the figures, in which:  
         [0005]      FIG. 1  shows the cross section through one particularly preferred switch according to the invention,  
         [0006]      FIG. 2  shows a plan view of a switching mat as illustrated in  FIG. 1 ,  
         [0007]      FIG. 3  shows the detail X from  FIG. 1 , and  
         [0008]      FIG. 4  shows a partial section through the switch from  FIG. 1  in a first latching switching position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0009]     The particularly preferred exemplary embodiment of a switch according to the invention has an operating rocker  1 , transmission elements in the form of light boxes  2 , a switching mat  3 , a printed circuit board  4  and a housing  5 . The operating rocker  1  has tabs  1   a,    1   b  and two projections in the form of rollers  6 ,  7 . The operating rocker  1  can be deflected radially about an axis A. The switching mat  3  has keys  8  with key heads  9  which are connected via key feet  10  to a base plate  11  of the switching mat  2 . Between the keys  8 , the switching mat  2  has a sprung element  12  with a surface  13  having a cross section in the form of waves. The sprung element  12  has a cavity  14  between its lower face and the printed circuit board  2 . Contact elements  15  are arranged on the lower faces of the key heads  9  and may be composed, for example, of carbon or conductive rubber.  
         [0010]     The lower faces of the light boxes  2  rest on the upper faces of the key heads  9 . Light-emitting diodes  16  and contact surfaces  17   a - d  are arranged on the printed circuit board  4 . The contact surfaces  17   a, b  and  17   c, d  are in each case electrically isolated from one another.  
         [0011]      FIG. 2  shows light openings  18  and the position of the contact elements  14  in the key heads  9 ; the figure also shows the corrugated surface  13  and the base plate  11 .  
         [0012]     In  FIG. 3 , the rollers  5 ,  6  are each illustrated twice; shaded in one position which corresponds to the position in  FIG. 1 , and not shaded in the position which would correspond to the position if pressure were applied to the right-hand side of the surface of the operating rocker  1 , thus pushing the right-hand key head  9  downwards with its contact element  15  electrically connecting the contact surfaces  17   c, d  to one another. Since the roller  17  is located in the central trough in the corrugated surface  13 , the roller  7  and hence the operating rocker maintain their position.  
         [0013]      FIG. 4  shows the switch from  FIG. 1  in a switching position which occurs when pressure has already been applied to the left-hand side of the surface of the operating rocker  1 . The roller  6  is latched in the central wave trough of the corrugated surface  13  of the sprung element  12 . Thus, via the tab  1   a,  the operating rocker  1  presses the left-hand light box  2  against the surface of the right-hand key head  9  in such a way that the key feet  10  bend in, and the contact element  15  electrically connects the two left-hand contact surfaces  17   a, b  on the printed circuit board  5  to one another. The light-emitting diodes  16  which are arranged in front of the contact surfaces  17   a, b  are not shown, to assist clarity. The illumination of pictograms  18  which are arranged in the operating rocker  1  is shown on the right-hand side in  FIG. 4 : light beams  20  from the light-emitting diodes  16  pass through the light openings  18  through the right-hand light box  2  and illuminate a pictogram  19  in the operating rocker  1 . The left-hand pictogram  19  is illuminated in a corresponding manner by the light-emitting diodes which are not shown on the left-hand side. When the operating rocker  1  is operated in a latched position as illustrated in  FIGS. 1, 2  and  4 , at least one roller  6 ,  7  is located in a wave trough in the corrugated surface  13 , that is to say the roller  6  as illustrated in  FIG. 4 , the roller  7  as illustrated in white in  FIG. 3  and both rollers  6 ,  7  as illustrated in black in  FIGS. 1 and 2 . Rotation of the operating rocker about the axis A results in at least one of the rollers  6 ,  7  being pressed against a rising area of the corrugated surface  13 . Starting from the switching position illustrated in black in  FIG. 1  or  FIG. 3 , the elasticity of the sprung element  12  pushes the rising surface downwards, so that either the roller  6  or the roller  7  moves into the central wave trough of the corrugated surface  13 . Since one of the contact elements  15  is then resting on the contact surfaces  17   a, b  or  17   c, d,  the movement cannot be continued, and the switch remains in the last position even if an operator releases the operating rocker  1 , since at least one of the rollers  6 ,  7  is located in a wave trough, so that an additional force is required to move it to the next wave trough and hence to the next switching position. If one of the rollers  6 ,  7  is not installed, this results in a switch which has a latching function in one direction and has a momentary-contact function in the other direction. If, for example, the roller  6  is omitted, the switch acts as a momentary-contact switch when pressure is applied to the left-hand side of the operating rocker since the roller  7  does not need to overcome any resistance; when pressure is applied to the right-hand side of the operating rocker as a latching switch, the roller  7  latches in the central wave trough. If both the rollers  6 ,  7  are omitted, this results in a pure momentary-contact switch. Thus, depending on which of the rollers  6 ,  7  is or are fitted to the operating rocker  1 , this may result in a pure latching switch, a pure momentary-contact switch or a combined latching/momentary-contact switch. The elasticity of the sprung element  12  can be modified by the choice of material and by the configuration of the element, in particular by its thickness, the depth of the wave troughs and the height of the wave peaks that have to be overcome. The elasticity can also be influenced by varying the cavity  14 .