Abstract:
A flush-mounted switch, in particular a door-opener switch, for mounting on a fastening surface, has a tubular housing and a flange which protrudes over the cover and an axially moveable button for actuating a switching member connected to the housing. The button is held in its rest position by a restoring force and can be pushed in counter to the action of this restoring force. A fastening ring affixes the door-opener switch on the fastening surface. The flange of the housing covers the fastening ring. A support ring is provided by way of which the button is lockable to the fastening ring.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a flush-mounted switch, in particular a door-opener switch, for mounting on a fastening surface, having a flange which protrudes over the cover, as seen from the direction of use of the door-opener switch, and has an axially moveable button for actuating a switching member connected to the housing, which button is held in its rest position by a restoring force and can be pushed in counter to the action of this restoring force. 
       PRIOR ART 
       [0002]    A flush-mounted switch of this kind as a door-opener switch having the features of the preamble of claim  1  is known from EP 0 749 136 by the applicant, which combines the advantages of an electronic switch having a short switching path with the advantages of a mechanical switch, in particular the robustness thereof. 
         [0003]    A further switch of this kind is known from EP 1 245 133, which discloses a door-opener switch having a large push cap with a short switching path. For ease of use and approval as a switch in particular in public transport, it is frequently necessary to equip such switches with lighting elements, which are able to visually display clearance for activation and also activation itself, it being intended for these visual displays for clearance and activation to be different from one another. 
       SUMMARY OF THE INVENTION 
       [0004]    On the basis of this prior art, it is an object of the present invention to configure such a known flush-mounted switch, in particular a door-opener switch, with as large a push cap as possible. In this case, a push cap is understood to mean the activation surface, that is to say that surface of the switch on which pressure leads to activation of the function. 
         [0005]    In this case, it is a further object of the invention to configure the push cap, in spite of its size, in such a way that pressure on any desired region thereof leads to reliable activation of the function; thus, in particular, that in the case of a circular push cap, even pressure on the latter in a region close to the rim of the circle leads to reliable activation and not just pressure on the central region. 
         [0006]    A further disadvantage of the prior art is that the size of the push cap is limited by a protruding fastening ring, which is provided to cover the inserted switch and in particular the fastening screws thereof, which, next to the activation surface of the push cap, connect the switch to a panel. 
         [0007]    It is another object of the invention to specify a flatter switch which activates reliably and is suitable for use outside, i.e. is preferably watertight, in particular splash-watertight, and in the process protected with regard to the use of high-pressure cleaners (IP69K). 
         [0008]    On account of the fact that the switch has a push cap, which fills virtually the entire cross section as seen from above, virtually the entire overall width of this button can be used as an activation surface. The button includes a fastening ring which is first of all fastenable to a panel by way of correspondingly provided fastening elements, in particular screws. By way of the bayonet shoulders provided on this fastening ring, it is possible, after the previously assembled door-opener switch has been positioned, to lock the latter to the panel, in that a support ring is placed on the unit consisting of the fastening ring and button unit, said support ring being latched securely with the fastening ring by way of complementary bayonet shoulders. In this case, the inner side of the support ring has a locking tab, which prevents undesired detachment of the support ring. Thus, the activation surface of the button covers the fastening elements on the panel and therefore has a larger surface area than its own basic fastening surface area. 
         [0009]    A further object of the present invention is to increase the modularity of the door-opener switch. This is achieved in that the switch has a plug-in cable connection. 
         [0010]    A further aim of the invention is to specify a switch that activates reliably and has a very small overall height and a large push cap. Such a large push cap having a small overall height has the problem that, in the case of a sealed configuration, which is advantageous for use outside, there is a displacement problem with the air cushion to be displaced by the pressing down of the button. This object is achieved according to the invention in that an axially moveable plastic diaphragm is provided in the cover, which plastic diaphragm can be moved with respect to the housing and thus allows the air column within the closed switch to move. 
         [0011]    These features can be used on their own or in combination. Further embodiments are given in the dependent claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Preferred embodiments of the invention are described in the following text on the basis of the drawings, which serve merely for illustration, are not to be interpreted in a limiting manner, and in which: 
           [0013]      FIG. 1  shows an exploded view showing the essential elements of the mountable door-opener switch according to one exemplary embodiment of the invention in front of a panel, 
           [0014]      FIG. 2  shows an exploded view of the individual parts of the button of the door-opener switch according to  FIG. 1  prior to mounting, 
           [0015]      FIG. 3  shows a cross-sectional view through the door-opener switch according to  FIG. 1 , including fastening elements but without the panel, 
           [0016]      FIG. 4  shows a view from below of the switching mat of the door-opener switch, 
           [0017]      FIG. 5  shows a view from below of the door-opener switch with the fastening ring, 
           [0018]      FIG. 6  shows a perspective view from above of the cover of a door-opener switch as per a further exemplary embodiment of the invention, and 
           [0019]      FIG. 7  shows a cross-sectional view through the assembled door-opener switch according to  FIG. 6 . 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0020]      FIG. 1  schematically shows an exploded view of a mountable flush-mounted switch in the form of a door-opener switch as per one exemplary embodiment of the invention in front of a panel  50  on which it is intended to be mounted, and having a plug  40  for the electrical connection. The door-opener switch thus has three subassemblies, which have been given the reference signs  10 ,  20  and  30  and which are described in the following text.  FIG. 2  shows an exploded view of the door-opener switch according to  FIG. 1 , with the individual elements that make up the subassemblies.  FIG. 3 , to which reference is also already made in this connection, shows finally a cross-sectional view of the door-opener switch in the assembled state, with fastening screws  21 , but without the panel  50  or the plug  40 . Apart from opening doors, such a flush-mounted switch can also be used for a multiplicity of other switching functions, such as requesting light signals, elevators and other tasks, in which a large actuation surface is sensible and a visual response and high security against vandalism are desired. 
         [0021]    One of the three subassemblies mentioned comprises a central button  10 , which comprises an activation push cap  11 , which makes up and fills the entire round extent of the button  10 . In the center of the push cap  11  there is a depressed region  114 , in which a symbol insert  12  can be inserted. The push cap  11  is connected to a welding ring  13 , in particular by sonic welding via the seal  112 . A housing  14  projects downwardly out of the subassembly, and so the button  10  has a protruding flange region  15 . The flange region  15  protrudes over the cover  14 , as seen from the direction of use of the door-opener switch. Its structure can be seen from  FIG. 3  and  FIG. 5 . 
         [0022]    The flange  15  is provided to be positioned on the fastening ring  20 , and has for this purpose a complementary configuration on its underside, said fastening ring  20  previously being fastened to, for example, a panel  50  during mounting of the door-opener switch. The panel  50 , which may be part of a door and is then usually aligned vertically, has a housing receptacle  51 , which may be a simple through-hole or blind hole, for receiving the cover  14  with a substantially precise fit, and a number of screw holes  52 . Three screw holes  52  are provided here, corresponding to three screw openings  23  in the fastening ring  20 . The three countersunk screw openings  23  are provided at an angular spacing of 120 degrees to one another in orientation flanges  22  on the fastening ring. In principle, it would also be possible to make the material of the fastening ring  20  thicker in the radial direction, if there is only at least one orientation element which keeps the button  10  in a rotationally fixed manner with respect to the fastening ring  20 . As can be seen in connection with  FIG. 2 , there are corresponding trapezoidal fastening recesses at the locations of the fastening orientation flanges  22 , so that the button  10  can be inserted in a rotationally fixed manner on the fastening ring  20 . To this extent, it is essential that the fastening ring  20  does not, seen radially, have a uniform internal configuration. This is achieved here by the receptacles  22  of the screw openings  23 . The orientation element can also be given by a non-round cover  14 , which is insertable into a then complementary receptacle  51  in the panel in precisely one or (for example in the case of polygons) in various positions. 
         [0023]    Instead of a screw connection, the fastening ring  20  can also be designed for a rivet connection or it can in principle be attached by welding, soldering or adhesive bonding. What is essential is the alignment of the fastening ring  20  for aligning the symbol field  12  via the fastening recesses  64  of the button  10 . 
         [0024]    The fastening ring  20  has here three bayonet shoulders  24 , which protrude outwardly on the flanges  22  and do not make up the entire height of the fastening ring  20 . In other words, under the protruding bayonet shoulders  24  there is a lower rim  26  as far as the lower edge of the fastening ring  20 . As in the case of the fastening holes  23  themselves, there can also be different shapes and numbers of these bayonet shoulders  24 ; there do not have to be three bayonet shoulders  24  and they do not have to be at the same angular spacing; what is essential is that it is possible to lock the button  10  by way of the support ring  30  which engages over said bayonet shoulders  24  and will be described further below. Instead of the bayonet shoulders, it is possible also to provide a snap connection, so that the fastening ring  20  is snapped on and latches in place with a click. In the case of another solution, the fastening ring  20  can also be fastened by way of laterally and radially extending screws. 
         [0025]    The fastening ring  20  further has an outwardly directed locking tab  25 , which can be brought into engagement with a complementary tab which cannot be seen in the support ring  30  in  FIG. 1 . By rotation of the support ring  30  in a manner corresponding to the arrows indicated on the fastening ring  20 , the inner tab provided in the support ring  30  runs onto the inclined flank or ramp  27  of the locking tab  25  until it slides into the space, located behind the latter, in the receptacle and thus locks the support ring  30  with respect to the fastening ring  20 . Advantageously, a lateral service opening  35  is provided in the support ring  30 , it being possible by way of said service opening  35  to push back the fastening ring  20 , the material of which is thin in the region of the locking tab  25  and partially the ramp  27 , so that the support ring  30  can then be rotated in the opposite direction to the arrows indicated on the fastening ring  20  and can thus be released. 
         [0026]    The support ring  30  itself has a cylindrical side wall  34 , on the outer side of which said service opening  35  is provided, specifically precisely next to the tab, which projects inwardly, counterclockwise as seen from above, and which, when the switch is assembled, comes to lie next to the run-on ramp  27  and the end, the tab  25 , thereof. 
         [0027]    On its top side, the support ring  30  is provided with an inwardly directed collar  31 , which is supported on a complementary shoulder  16  of the button  10 . The inner edge of the collar  31  projects to the outer rim of the push cap  11 , in particular in the unpressed state of the push cap  11 . 
         [0028]    Provided on the lower edge of the side wall  34  of the support ring  30  are in this case three inwardly projecting bayonet shoulders  32 , which can be interlocked with the complementary shoulders  24  of the fastening ring  20 ; in other words, in the mounted state of the support ring  30  in which it is locked by the tab  25 , the inwardly projecting bayonet shoulders  32  are located precisely opposite the lower rim  26  underneath the bayonet shoulders  24 . The number and shape of these elements are therefore configured in a complementary manner. The elevations  33  serve to center the support ring  30  during mounting. 
         [0029]    Provided on the underside of the cover  14  itself is the plug receptacle  142 , which can be seen in  FIG. 2  and into which the plug  40  can be plugged. The snap-action lug  43  secures the plug against undesired detachment and thus serves as a protection against falling off. In order to detach the plug connection, the lug  43  is raised and the plug withdrawn. The electrical contacts are in this case cast in the plug  40 . An O-ring  41  seals the contact point with respect to penetrating moisture. The plug  40  is then connected in a conventional manner to a cable  42 . In this way, it is possible to supply the door-opener switch as the abovementioned subassemblies without a pigtail, thereby increasing service-friendliness. 
         [0030]      FIG. 2  shows in somewhat more detail an exploded view of the button  10 , before the latter is assembled. The central element of the button  10  is the housing  60 , which has towards the inside an opening, into which the cover  14  can be placed from below. 
         [0031]    Advantageously, there is provided in this interior space a loudspeaker plate  61  which forms a bracket and onto which there can be placed a foam mat  62 , to which the loudspeaker  63  is applied. The loudspeaker  63  then projects through a loudspeaker opening  73  in the circuit board  70 . The housing  60  has, in the form illustrated in  FIG. 2 , the non-planar underside, which has three trapezoidal fastening recesses  64 , which are then provided for the orientable locking of the cover on the fastening ring  20 . 
         [0032]    The circuit board  70  having a large diameter, which approaches the size of the push cap  11 , has in this case three cutouts  75 , which are provided at an irregular angular spacing, at a radial spacing which corresponds to the housing diameter, the three complementary fastening latches  65  of the cover  60 , which fix the circuit board  70  in the housing  60 , projecting through said cutouts  75 . The angular spacings could also be provided at different spacings, in particular also equally at a spacing of 120 degrees. The circuit board  70  is otherwise preferably round having three trapezoidal recesses  74  on the circumference, said recesses  74  being complementary to the recesses  64  in the housing  60 . The electric circuit is applied in a conventional manner, preferably using SMD technology, to the circuit board  70 , but is not illustrated here. In order to illuminate the door-opener switch, there is provided at least one light guide  72 , which can be plugged in particular onto the circuit board  70 . In the case of the exemplary embodiment illustrated, it comprises, in two concentric portions  76  and  77 , in each case three guide portions, which cover an angular portion of 120 degrees and are separated by LED receptacles, which cannot be seen in  FIG. 2 , such that three LEDs are provided for the outer portion  77  and three LEDs are provided for the inner portion  76 , said LEDs activating the individual visual displays. 
         [0033]    The push cap  11  is preferably a translucent injection molded part, resembling for example smoked glass, in a soft spring element  112 , which is attached by one-component or two-component injection molding and after mounting is connected in a fixed manner via the welding ring  13  to the housing  60 . The one-component or two-component execution of the connected element of push cap  11  plus axial spring element  112  ensures a sealed connection. The push cap  11  has an outer raised circular ring  113 , which makes up a part of the outer actuating surface. This circular ring  113  is beveled on the inside and is adjoined by a depression  114  which has in this case three locking shoulders  115 , under which there is a free space. In this case, the elevations  131  on the circular ring  113  play a role in the orientation of the elements to be connected. 
         [0034]    Provided in the center of the push cap  11  in the illustrated exemplary embodiment are four trapezoidal openings  11 , which are provided in particular for better transmission of the acoustic signal that can be generated by the loudspeaker  63 . These openings  111  are dispensed with for the variant without a loudspeaker; however, they can also be dispensed with in a configuration with a loudspeaker or only three of them could be provided. In order to provide sealing with respect to the exterior space of the door-opener switch, a diaphragm film  121  is placed on the depression  114  and is attached to the latter for example by sonic welding or adhesive bonding. A planar symbol insert  12  having a symbol  122 , which is printed on or is present in an incorporated raised or sunken manner, is locked in the depression  114  via the locking shoulders  115  such that corresponding bayonet elements  123  are provided on the underside of the symbol insert  12 . In other words, the symbol insert  12  is placed on the depression  114  so that the bayonet shoulders  123  are arranged between the bayonet element  115  and subsequently the symbol insert  12  is rotated about the longitudinal axis of the button  10  and thus locked. 
         [0035]    Provided as a receptacle  116  in the center of the depression  114  is an elevation, into which the switching mat  171  having a corresponding centered rubber element can be inserted from below. The switching mat  71  is illustrated in more detail in  FIG. 4 , which shows a view from below of the switching mat  71  of the door-opener switch. The material of the switching mat  71  is substantially flexible rubber. The switching mat  71  has a central switching mat elevation  171 , which fits precisely into the complementary opening in the push cap  11 , said opening being provided on the underside of the receptacle  116 . This switching mat elevation  171  merges at its edges into a flange which forms the basic surface area  172  of the switching mat  71 . Provided to the side of this surface area  172  are two opposing lateral projections  174 , with in each case one fastening foot  175  being preferably integrally molded on each projection  174  on the side opposite the switching mat elevation  171 . These fastening feet  175  are provided to be inserted into corresponding openings on the circuit board  70 . Provided on the circuit board is a central first contact and a second contact, which is arranged in a preferably circular manner around this first contact at a spacing having an isolating gap, wherein the switch is activated when the two contacts are connected. For this purpose, a central recess  176  has been provided in the switching mat  71 , said central recess  176  having a central electrically conductive metal plate  173  which forms the conductive switching surface. By way of a pressure at any point on the push cap  11 , the central switching mat elevation  171  is pressed down; this causes the conductive switching surface  173  in the recess  176  to snap over and leads to the closing of the contact. 
         [0036]    As a result of the use according to the invention of the fastening ring  20 , it is possible to fasten the door-opener switch by means of the necessary screws  21  within the diameter of the push cap  11  and thus underneath the activation disk of the button  10  and thus under the button  10 . This makes it possible to construct a smaller switch in the case of an activation diameter of the same size or to achieve a larger activation surface in the case of a switch of the same size. On account of the arrangement of the smoked-glass push cap  11 , the activation surface thereof can be used directly also as a translucent surface. 
         [0037]    On account of the depression  114  in the push cap  11  having the insert  12 , it is possible to achieve better guidance for the user. Although it is possible to activate the switch at any point on the push cap  11 , since activation takes place centrally via the switching mat  71 , the depression provides the user more simply with a haptic confirmation of his actuation. 
         [0038]    A problem with the switch according to this design is the pressure equalization, since, on account of the wide activation surface, even with a short switching path a considerable displacement of air takes place, and this air cannot escape in the now sealed switch. A housing which is known from the prior art and is closed off in a permeable manner by a foam material is possible for pressure equalization over a relatively long time, and thus in a door-opener switch for a mountain railroad train which travels through regions at various heights and is used there, but this element is not suitable for ensuring pressure equalization in the case of button activation, since in this case the equalization has to take place quickly, i.e. within a few milliseconds. 
         [0039]    Therefore, according to  FIG. 5 , the pressure equalization means is integrated according to the invention in the cover  14 , since the air displaced by the movement of the push cap  11  during switching can expand and be distributed directly within the cover  14  and thus pressure equalization with respect to the outside is ensured. 
         [0040]      FIG. 5  shows a view from below of the door-opener switch having the fastening ring  20  and the housing  14 . The support ring  30  is likewise already placed on the button  10 , and so the locking thereof is directly discernible. The tab  25  is present on a protruding bayonet shoulder  32  and can be released by pressure on the service opening  35 . The bayonet shoulders  32  on the circumference of the support ring  30  engage over the bayonet shoulders  24  of the fastening ring  20 , which are arranged in a complementary manner. During mounting on a panel  50 , the fastening screws would then project through the openings  23  into the panel. 
         [0041]    The light guide  72  consists of two rings  76  and  77  separated by a partially executed incision, the light guide  72  being interrupted in a known manner by radially provided incisions; these provide what are known as hotspots at which the light supplied by the LEDs that emit to the sides can escape from the light guide  72  in the axial direction of the door-opener switch, in particular through the push cap  11 , and is clearly discernible to the user in a manner scattered by the smoked glass, regardless of the external light conditions. Moreover, on account of the smoked-glass coloration of the push cap, the lighting contrast is increased, thereby improving the discernibility of the lighting in sunshine. 
         [0042]    In  FIG. 3 , the two inner  76  and outer  77  light guides can be seen, the location of an LED being provided with the reference sign  78 . 
         [0043]    The pin strip  141  produces the electrical connection between the cover  14  and the circuit board  70 . 
         [0044]      FIG. 6  shows a perspective view from above of the cover  14  of a door-opener switch according to a further exemplary embodiment of the invention. Identical features are provided in the drawings with identical reference signs. The upwardly open cover  14  has at its upper rim a circumferential connecting bead  143 , which is inserted into a complementary opening in the housing  60  and is attached for example by sonic welding. A latching connection is also possible. In  FIG. 7 , which shows a cross-sectional view through the assembled door-opener switch according to  FIG. 6 , this connection can be seen. 
         [0045]    Six contact pins  144 , which are connected electrically to the circuit board  70  in a socket strip  79  fastened to the circuit board  70 , emerge from the pin strip  141 . 
         [0046]    A difference from the exemplary embodiment in  FIG. 1  resides in the pressure equalization diaphragm  145 , which is a silicone diaphragm. Provided in the base  148  of the cover  14  is an inwardly directed hollow-cylindrical wall  147 , on the free end of which the circumferential clamping bead  146  of the pressure equalization diaphragm  145  is placed in a sealing manner. It is maintained that hollow-cylindrical does not imply a circular wall  147 . A hollow prism or an ellipse is also a hollow cylinder. The pressure equalization diaphragm  145  has a thin, elastic diaphragm wall, which can expand in particular between the hollow-cylindrical walls  147  of the cover  14  in the direction of a pressure equalization opening  150  which is located centrally between the walls  147  in the base  148  of the cover  14 . 
         [0047]    The function is in this case as follows.  FIG. 7  shows the rest position of the push cap  11 , in which the latter is spaced apart above the circuit board  70  so that there is a cavity  151  between the circuit board and the push cap and, of course, further air-containing spaces throughout housing  60 , which is sealed off by the cover  14 . Pressure differences between the environment and this internal cavity  151 , which result when the switch is used at doors of mountain vehicles on account of the latter traveling over a period of several minutes up to an hour from a valley station to a mountain station, can be compensated by diffusion of air through the pressure equalization diaphragm  145 . It is somewhat different when the switch is actuated, said actuation taking place rapidly in fractions of a second and likewise displacing the air column. On account of the flat construction of the push cap with a large actuation surface, a certain quantity of air has to be displaced despite the short switching path. This quantity of air can now flow through openings in the circuit board  70  into the region of the pressure equalization diaphragm  145  and push out the latter downwardly in the direction of the pressure equalization opening  150 , since there is a direct connection to the environment via this opening  150 . In this case, the sealing of the switch remains ensured. 
         [0048]    The quantity of air displaced out of the no longer existing cavity  151  forms an air column in the then expanded diaphragm cavity  152  between the walls  147  of the cover  14 , held by the diaphragm wall  149  and secured by the small opening  150 , so that air can escape or flow in, but no physical damage to the diaphragm need be feared. The pressure equalization diaphragm  145  can also be called a diaphragm bellows. It may have a bellows-like wall (not illustrated in the drawings). Particularly when no such bellows walls that slightly extend the cavity are present, an additional restoring force, which corresponds to the stretching of the diaphragm material, is also generated when a user releases the pressure on the push cap  11  again. 
         [0049]      FIG. 7  shows yet further changes to the region of the push cap  11  in the exemplary embodiment with respect to  FIG. 1 . These changes can also be used on their own in an exemplary embodiment according to  FIG. 1  and the embodiment of  FIG. 1  can also be used only with a diaphragm  145  according to  FIG. 6 . 
         [0050]    Instead of the circular axial spring element  112 , which is fastened to the push cap  11  preferably during the production process, and is then welded to the housing  60  by way of the welding ring  13 , it is also possible to provide a spring surface which is formed by the spring element  212 , is in the form of a circular ring in plan view, and has an inner bead  213  and an outer bead  214 . The outer bead  214  is clamped, in a similar manner to in  FIG. 1 , in a receptacle between the housing  60  and the welding ring  13  and the housing  60  and welding ring  13  are then preferably welded. The inner bead  213  is received in a receptacle in an additional ring  215 , with in this case, too, the additional welding ring  215  and the push cap  11  then preferably being welded. 
         [0000]    
       
         
               
             
               
               
             
           
               
                   
               
               
                 LIST OF REFERENCE SIGNS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 10 
                 Button 
               
               
                 11 
                 Push cap 
               
               
                 12 
                 Symbol insert 
               
               
                 13 
                 Welding ring 
               
               
                 14 
                 Cover 
               
               
                 15 
                 Flange 
               
               
                 16 
                 Shoulder 
               
               
                 20 
                 Fastening ring 
               
               
                 21 
                 Countersunk screw 
               
               
                 22 
                 Orientation flange 
               
               
                 23 
                 Countersunk screw 
               
               
                   
                 opening 
               
               
                 24 
                 Bayonet shoulder 
               
               
                 25 
                 Locking tab 
               
               
                 26 
                 Lower edge 
               
               
                 27 
                 Ramp 
               
               
                 30 
                 Support ring 
               
               
                 31 
                 Collar 
               
               
                 32 
                 Bayonet shoulder 
               
               
                 33 
                 Centering ribs 
               
               
                 34 
                 Side wall 
               
               
                 35 
                 Collar 
               
               
                 40 
                 Plug 
               
               
                 41 
                 Plug strip 
               
               
                 42 
                 Connection cable 
               
               
                 43 
                 Snap-action lug 
               
               
                 50 
                 Panel 
               
               
                 51 
                 Housing receptacle 
               
               
                 52 
                 Screw hole 
               
               
                 60 
                 Housing 
               
               
                 61 
                 Loudspeaker platform 
               
               
                 62 
                 Foam buffer 
               
               
                 63 
                 Loudspeaker 
               
               
                 64 
                 Trapezoidal fastening 
               
               
                   
                 recess 
               
               
                 65 
                 Fastening latches 
               
               
                 70 
                 Circuit board 
               
               
                 71 
                 Switching mat 
               
               
                 72 
                 Light guide 
               
               
                 73 
                 Loudspeaker opening 
               
               
                 74 
                 Trapezoidal fastening 
               
               
                   
                 recess 
               
               
                 75 
                 Cutouts for snap locks 
               
               
                 76 
                 Inner light guide 
               
               
                 77 
                 Outer light guide 
               
               
                 78 
                 LED 
               
               
                 79 
                 Socket strip 
               
               
                 111 
                 Cutout 
               
               
                 112 
                 Axial spring element 
               
               
                   
                 (seal) 
               
               
                 113 
                 Circular ring 
               
               
                 114 
                 Depression 
               
               
                 115 
                 Locking shoulders 
               
               
                 116 
                 Receptacle 
               
               
                 121 
                 Diaphragm film 
               
               
                 122 
                 Symbol insert 
               
               
                 123 
                 Bayonet shoulders 
               
               
                 131 
                 Orientation tab 
               
               
                 141 
                 Pin strip 
               
               
                 142 
                 Plug receptacle 
               
               
                 143 
                 Connecting bead 
               
               
                 144 
                 Contact pins 
               
               
                 145 
                 Pressure equalization 
               
               
                   
                 diaphragm 
               
               
                 146 
                 Clamping bead 
               
               
                 147 
                 Wall 
               
               
                 148 
                 Base 
               
               
                 149 
                 Diaphragm wall 
               
               
                 150 
                 Pressure equalization 
               
               
                   
                 opening 
               
               
                 151 
                 Cavity 
               
               
                 152 
                 Diaphragm cavity 
               
               
                 171 
                 Central switching mat 
               
               
                   
                 elevation 
               
               
                 172 
                 Basic surface area 
               
               
                 173 
                 Conductive switching 
               
               
                   
                 surface 
               
               
                 174 
                 Lateral projection 
               
               
                 175 
                 Fastening foot 
               
               
                 176 
                 Depression 
               
               
                 212 
                 Spring element 
               
               
                 213 
                 Inner bead 
               
               
                 214 
                 Outer bead 
               
               
                 215 
                 Intermediate ring