Abstract:
The invention relates to a modular selection button for actuating contact elements. Said button comprises a housing ( 6 ), spring-loaded switching lugs ( 81 ) and according to requirements a control switch ( 10 ), a rotary knob ( 11 ) or a key-operated switch ( 2 ) as a rotating actuator, in addition to one of several transmission members ( 4; 4′; 5; 5′ ), which transmits the movement from the actuator ( 10; 11; 2 ) to the switching lugs ( 81 ) via switching cam elements ( 42; 52 ). Stops and counter-stops which are fixed and displaceable respectively with respect to the housing ( 6 ) form various stop elements that can be used to select the number of switching positions and actuation modes. The various stops are configured on the housing ( 6 ), on the key-operated actuator ( 2 ) and on the second stop slides ( 92 ) that are to be inserted into the housing ( 6 ). The various counter-stops are configured in the control switch ( 10 ), in the rotary knob ( 11 ) and on the transmission members ( 4; 4′; 5; 5′ ).

Description:
BACKGROUND 
   The present invention relates to a modular selection button for actuating contact elements, the modular selection button including a rotating handle and at least one switch plunger supported in a housing. 
   German Patent Publication DE-C2-35 41 390 describes such a selection button featuring a rotating handle, a transmission member, and stops. The substantially cylindrical transmission member is non-rotatably coupled to the handle, carries an axially acting switching cam which is closed upon itself as well as a stop boss, and is supported in a housing. To limit the angle of rotation, the stops cooperate with the stop boss and are formed in stop rings of which one is replaceably and non-rotatably arranged in the housing. Located between the stops is a circular path segment which, from stop ring to stop ring, spans a different angle and with which in each case the stop boss engages. The switching cam is configured as a projecting shoulder at the lateral surface of the transmission member and cooperates with at least one switch plunger of a contact element. The switch plunger is arranged in the housing in a manner that it is non-rotatable as well as axially movable against the action of a spring and intended to actuate the contact plunger of the contact element. The direction of rotation of the handle determines which of the two switch plungers is moved. The rotation of the handle which is limited by the respective stop ring determines, on one hand, the number of possible switching positions, that is two or three switching positions and, on the other hand, the actuation mode which is the momentary contact mode, i.e., monostable, when rotated by 45° whereas it is the latching mode, i.e., bistable, when rotated by 90°. It is a disadvantage that, for changing the actuation mode, the user has to disassemble the selection button to replace the stop ring. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a modular selection switch in which making changes in the actuation mode is relatively easy and which has a relatively large number of variants. 
   The present invention provides a modular selection button for actuating contact elements. The selection button includes:
         a housing;   a rotating handle;   a disk-shaped transmission member supported in the housing and non-rotatably coupled to the handle, the transmission member including at least one axially projecting and axially acting switching cam element disposed on a rear side thereof;   a first stop device including at least one first stop disposed the housing and fixed relative to the housing and a first counterstop disposed on the handle and rotatable using the handle, the first stop device configured to limit a first angle of rotation of the handle, the first stop device useable for a first latching mode of the selection button, the first latching mode having a first resting position, a first clockwise latched rotated position and a first counterclockwise latched rotated position;   a second stop device including at least one second stop disposed on the housing and fixed relative to the housing and a second counterstop disposed on the transmission member and rotatable using the handle, the second stop device limiting a second angle of rotation of the handle, the second stop device useable for a second latching mode of the selection button, the second latching mode having a second resting position and a second clockwise latched rotated position; and   at least one switch plunger supported in the housing so as to be non-rotatable and axially movable against a spring device, the at least one switch plunger including a symmetrically formed end face configured to cooperate with the at least one switching cam element, the transmission member being capable of latching onto the switch plunger using the end face and the switching cam element when a predetermined angle of rotation of the handle is reached.       

   According to a first embodiment of the present invention, there are varied possibilities both for the type of handles to be used and for the actuation modes the disk-shaped design of the transmission member featuring switching cam elements projecting from the rear side and due to the formation of the permanently existing first and second stop devices and the fifth stop device, which may be provided as required. Finger-grip knobs, rotary knobs or equally acting actuating elements can be used as rotating handles. The selection switch can be provided with two or three switching positions and in this context, in turn, with latching or momentary contact actuation mode. Without having to be disassembled, the selection button can be easily programmed from the latching into the momentary contact actuation mode or vice versa by inserting or removing two stop slides on the rear side. 
   According to a second embodiment of the present invention, there are varied possibilities for the actuation modes due to the disk-shaped design of the transmission member featuring switching cam elements projecting from the rear side and due to the formation of the permanently existing third stop device and the fourth or fifth stop device, which may be provided as required. More or less complex key actuators are used as rotating handles. The selection switch can be provided with two or three switching positions and in this context, in turn, with latching or momentary contact actuation mode. Moreover, it is possible for the latching actuation mode to be modified in such a manner that, in the rotated position, the key is either released such as in the resting position or retained, that is to say that it is either possible or not possible to remove the key in the rotated position. Without having to be disassembled, the selection button can be easily programmed from the latching into the momentary contact actuation mode or vice versa by inserting, removing or mutually exchanging first or second stop slides on the rear side or, when in the latching mode, from the mode with releasable key into the mode with retained key or vice versa. 
   According to a third embodiment of the present invention, there are varied possibilities both for the type of handles to be used and for the actuation modes due to the disk-shaped design of the transmission member featuring switching cam elements projecting from the rear side and due to the formation of the permanently existing first to third stop means and the fourth or fifth stop means, which may be provided as required. Finger-grip knobs, rotary knobs, equally acting actuating elements, or more or less complex key actuators can be used as rotating handles. The selection switch can be provided with two or three switching positions and in this context, in turn, with latching or momentary contact actuation mode. When using a key actuator it is moreover possible for the latching actuation mode to be modified in such a manner that, in the rotated position, the key is either released such as in the resting position or retained, that is to say that it is either possible or not possible to remove the key in the rotated position. Without having to be disassembled, the selection button can be easily programmed from the latching into the momentary contact actuation mode or vice versa by inserting, removing or mutually exchanging first or second stop slides on the rear side or, when in the latching mode, from the mode with releasable key into the mode with retained key or vice versa. Thus, the third embodiment combines the features and advantages of the first and second embodiments. 
   In certain embodiments of the present invention, provision may be made for strip-like first or second stop slides provided with latching devices, the second stop slide differing from the first stop slide only by a notch in the front part for forming the respective stop faces. 
   In certain embodiments of the present invention, provision may be made for in each case paired switch plungers and first, second, or third stops as well as first or second stop slides can be used. If the selection button is provided with three switching positions, it turns out to be expedient for this purpose to use a first transmission member having in each case mirror-symmetric pairs of switching cam elements and to use fourth counterstops; however, if the selection button is provided with two switching positions, it turns out to be expedient to use a second transmission member featuring pairs of switching cam elements and to use second counterstops whose pair elements are in each case configured to be diagonally opposed and antisymmetric, that is laterally reversed. 
   In certain embodiments of the present invention, provision may be made for a sixth stop device to provide a definite resting position when the selection button is provided with two switching positions. 
   Finger-grip knobs, rotary knobs, or similar actuating elements are advantageously to be connected to the transmission member in a positive locking manner via rib- and slot-shaped segments. A further advantage follows from this in the case of two switching positions in that the handle can be connected to the transmission member in at least two engagement positions with respect to the housing. In this manner, it is possible, for example, to optionally implement either a vertical resting position and a rotated position which is angularly offset therefrom or a resting position which is angularly offset from the vertical and a rotated position of the handle which is symmetrically angularly offset therefrom. 
   By providing the transmission member with a light aperture, the selection button is made suitable for use with light-emitting elements. 
   In conjunction with a key actuator, in certain embodiments of the present invention the cylinder lock is non-rotatably connected to the housing as an additional part thereof via a cover, the lock core which can be rotated using the key is connected to the transmission member in a positive locking manner, and the third stop device acts between the fixed cylinder lock and the transmission member. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further details and advantages of the present invention follow from the following exemplary embodiment which will be explained on the basis of Figures. 
       FIG. 1  shows the totality of a selection button according to the present invention in a perspective, pulled-apart view; 
       FIG. 2  shows an enlarged view from a different perspective of the housing shown in  FIG. 1 ; 
       FIG. 3  shows an enlarged view from a different perspective of the finger-grip knob shown in  FIG. 1 ; 
       FIG. 4  shows an enlarged view from a different perspective of the key actuator shown in  FIG. 1 ; 
       FIG. 5  shows an enlarged view from a different perspective of the first transmission member shown in  FIG. 1 ; and 
       FIG. 6  shows an enlarged view from a different perspective of the second transmission member shown in FIG.  1 . 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows the component parts for the totality of all three of the modular selection button according to the present invention, namely: a finger-grip knob  10 , a rotary knob  11 , and a key actuator  2  as a rotating handle, a front ring  3 , a first transmission member  4 , a second transmission member  5 , a modified first transmission member  4 ′, a modified second transmission member  5 ′, a housing  6 , switch plungers  81  which each have one pressure spring  82 , first stop slides  91  and second stop slides  92 . 
   In the selection button according to the first embodiment, there exist, depending on the requirement, finger-grip knob  10  or rotary knob  11 , front ring  3 ; depending on the requirement, first or second transmission member  4  or  5 , housing  6 , one or two switch plungers  81  with their pressure springs  82 ; and, depending on the requirement, none, one, or two second stop slides  92 . 
   In the selection button according to the second embodiment, there exist key actuator  2 , front ring  3 ; depending on the requirement, modified first or second transmission member  4 ′ or  5 ′, housing  6 , one or two switch plungers  81  with their pressure springs  82 ; and, depending on the requirement, none, one, or two first or second stop slides  91  or  92 . 
   In the selection button according to the third embodiment, there exist, depending on the requirement, finger-grip knob  10 , rotary knob  11 , or key actuator  2 , front ring  3 ; depending on the requirement, first or second transmission member  4  or  5  or modified first or second transmission member  4 ′ or  5 ′, one or two switch plungers  81  with their pressure springs  82 ; and, depending on the requirement, none, one, or two first or second stop slides  91  or  92 . 
   Since the three embodiments are the same in many features and effects, these features and effects will be described in the following for two or all of the three embodiments together, correspondingly. 
   The two switch plungers  81  are inserted into housing  6  on the rear side, two widely spaced guide strips  61  in the interior of the essentially cylindrical housing  6  ( FIG. 2 ) in each case embracing the two outer edges  83  of the respective switch plungers in a guiding and retaining manner. Helical pressure springs  82  are each braced between a first abutment  84  in switch plunger  81  and a second abutment  62  in housing  6  so that switch plungers  81  are biased in the direction of the handle by pressure springs  82 . A third abutment  85  located opposite first abutment  84  in switch plunger  81  limits the movement in the direction of the handle by stopping at the rear side of second abutment  62 . Disk-shaped transmission member  4 ,  4 ′,  5  or  5 ′, is inserted into housing  6  from the front. Subsequent to placing handle  10 ,  11 , or  2  onto housing  6 , front ring  3  is slipped over handle  10 ,  11 , or  2  and snapped onto housing  6  at the front via usual snap-in locking elements. Thus, handle  10 ,  11 , or  2  is connected to the housing in a manner that it cannot be lost. In this connection, finger-grip knob  10  or rotary knob  11 , via a rear guide collar  13 , rotatably rests in a front guide groove  65  of the housing, whereas key actuator  2 , via a rear retaining collar  27 , rests in the guide groove in a non-rotatable manner. Stop slides  91  and  92  have a strip-like design and, at their rear part, feature radially projecting latching means  93  via which they engage with corresponding window-like mating latching means  64  of housing  6  after being inserted from behind between two narrowly spaced guide strips  61 , respectively. First transmission member  4  and second transmission member  5  are respectively provided with a centrical light aperture  45  or  55  (FIG.  5  and  FIG. 6 ) which allows finger-grip knob  10  or rotary knob  11  to be illuminated by a light source connected to the selection button on the rear side. Transmission members  4 ,  4 ′,  5  and  5 ′ are equipped with ring-shaped seals  40  on the edges which protect the interior of the selection button from entering moisture and compensate for tolerances between the movable parts. 
   According to FIG.  1  and  FIG. 5  or  FIG. 6 , two axially projecting switching cam elements  42  or  52  are respectively formed on rear side  41  or  51  of first transmission member  4  or  4 ′ or of the second transmission member  5  or  5 ′, the switching cam elements cooperating with front end faces  86  of switch plungers  81  in such a manner that, when transmission member  4 ,  4 ′,  5  or  5 ′ is rotated out of its resting position, switch plungers  81  are moved toward the rear against the action of pressure springs  82  for actuating contact elements which are not shown. Formed on finger-grip knob  10  and on rotary knob  11  on the rear side are mutually opposing rib segments  12  ( FIG. 3 ) which engage in a positive-locking manner with correspondingly configured mutually opposing slot segments  43  on front side  44  of first transmission member  4  or in slot segments  53  on front side  54  of second transmission member  5  during the placement of finger-grip knob  10  or rotary knob  11 . In this manner, a rotary motion of finger-grip knob  10  or rotary knob  11  is transmitted to first or second transmission member  4  or  5 , respectively. 
   According to FIG.  1  and  FIG. 4 , key actuator  2  is composed of a key  21  and a cylinder lock  22  which is fixed in a cover  23  in a positive locking and therefore unrotatable manner. Cover  23  features two noses  24  on the edge of its collar  27 , and housing  6  has two correspondingly configured grooves  63  in the upper edge area, via which grooves cover  23 , in turn, is mounted in housing  6  in its correct position. Diametrically opposing recesses  29  on the rear side of collar  27 , in cooperation with first stops  66  in guide groove  65  of housing  6 , effect the non-rotatability of cover  23  with cylinder lock  22  in housing  6 , hock core  25 , which is to be rotated by means of the key, features two strip-like formations  26  on its rear side, the strip-like formations engaging in a positive locking manner with correspondingly configured recesses  43 ′ or  53 ′ on front side  44 ′ or  54 ′ of modified first or second transmission member  4 ′ or  5 ′, respectively. In this manner, a rotary motion is transmitted from key  21  to modified first or second transmission member  4 ′ or  5 ′, respectively. 
   When using finger-grip knob  10  or rotary knob  11  as a handle, the selection button can be provided with three switching positions, namely with a middle resting position as well as one clockwise and one counterclockwise rotated position, respectively. In the case of this variant, first transmission member  4  shown in FIG.  1  and  FIG. 5  is used whose switching cam elements  42  mutually oppose each other at an acute angle. In the resting position, switching cam elements  42  are situated in the middle between the two switch plungers  81 . When rotating finger-grip knob  10  or rotary knob  11  in one or in the other direction, in each case one of the two switching cam elements  42  applies pressure to an in each case abutting slanted surface  87  of end face  86  of appertaining switch plunger  81  against its pressure spring  82 . If no stop slides are inserted, specific switching cam element  42 , with its cam tip  46 , reaches the region of a latching recess  88  of end face  86  of appertaining switch plunger  81 . The selection button remains in this latched rotated position until it is removed from this position by an intentional actuation. To limit the angle of rotation in both directions, provision is made for a first stop device which includes two diametrically opposing first stops  66  which are formed in guide groove  65  of housing  6  in a nose-shaped manner and directed radially outward and of two diametrically opposing first counterstops  14  which are formed on guide collar  13  of finger-grip knob  10  or of rotary knob  11  as ring segments in a manner that they are directed radially inward, the both radially and axially running side faces  67  of first stops  66  cooperating with corresponding side faces  15  of first counterstops  14 , respectively. 
   By inserting second stop slides  92  into housing  6 , provision is made for a fifth stop device which takes effect before the first stop device when the selection button is rotated out of the resting position. The fifth stop device includes diametrically opposing second stop faces  95  which are formed by the front part of narrow side  98  of formed second stop slides  92  which narrow side opposes the respective direction of rotation, and of two fourth counterstops  47  which are formed on rear side  41  of first transmission member  4  in a manner that they project radially and symmetrically oppose each other at an acute angle, second stop faces  95  cooperating with the both radially and axially running edge faces  471  of counterstops  47  which are angularly offset from switching cam elements  42 . In this manner, the angle of rotation of the selection button is limited so that it is no longer possible for the respective switching cam element  42  to reach, with its cam tip  46 , the region of latching recess  88  of end face  86  of appertaining switch plunger  81 . In this case, the selection button features the momentary contact mode in both rotated positions since, after releasing handle  10  or  11 , the selection button automatically returns from the rotated position to the resting position through the action of pressure springs  82  and the interplay of slanted surfaces  87  of switch plungers  81  with switching cam elements  42 . 
   When using finger-grip knob  10  or rotary knob  11  as a handle, the selection button can also be provided with two switching positions, namely with a resting position and a clockwise rotated position. In the case of this embodiment, second transmission member  5  shown in FIG.  1  and  FIG. 6  is used whose switching cam elements  52  diametrically oppose each other in a manner that they are laterally reversed, i.e., offset by 180°. In the resting position, switching cam elements  52  in each case abut on the slanted surface  87  of the two switch plungers  81  which runs ahead in the direction of rotation. When rotating finger-grip knob  10  or rotary knob  11 , each of the two switching cam elements  52  applies pressure to respective slanted surface  87  of appertaining switch plunger  81  against its pressure spring  82 . If no stop slides are inserted, specific switching cam element  52 , with its cam tip  56 , reaches the region of a latching recess  88  of end face  86  of appertaining switch plunger  81 . In this manner, the rotated position is latched. To limit the angle of rotation, provision is made for a second stop device including two diametrically opposing second stops  68  which each occur in the clockwise direction as end face of two sector-shaped recesses  69  diametrically formed in housing  6  and of two diametrically opposing second counterstops  59  which are formed on rear side  51  of second transmission member  5  in a manner that they project axially and oppose each other diametrically and that they are arranged radially outward in front of one of the switching cam elements  52 , respectively, second stops  68  cooperating with corresponding edges  591  of second counterstops  59 , the edges running ahead in the direction of rotation. For assuming the resting position which is brought about by pressure springs  82  and by the interplay of slanted surfaces  87  of switch plungers  81  with switching cam elements  52 , the selection button is equipped with a sixth stop device including fourth stops  70  which each occur in the counterclockwise direction as end face of two sector-shaped recesses  69  and of second counterstops  59 , fourth stops  70  cooperating with corresponding edges  592  of second counterstops  59 , the edges running after. 
   To implement the momentary contact operating mode, provision is made for a fifth stop device, again by inserting a second stop slide  92  into housing  6 , the fifth stop means taking effect before the second stop device when the selection button is rotated out of the resting position. In this case, the fifth stop device includes second stop face  95  of the only stop slide  92  and of a fourth counterstop  57 , which is formed on rear side  51  of second transmission member  5  in a manner that it projects axially, second stop face  95  cooperating with the both radially and axially running edge face  571  of counterstop  57 , which counterstop is angularly offset from switching cam elements  52 . In this manner, the angle of rotation of the selection button is limited so that it is no longer possible for the switching cam elements  52  to reach, with their cam tip  56 , the region of latching recesses  88  of end faces  86  of appertaining switch plungers  81 . 
   Finger-grip knob  10  is provided with a number of rib segments  12  greater than the number of slot segments  53  of second transmission member  5 . Because of this, it is possible for finger-grip knob  10  to be optionally brought into two different engagement positions with second transmission member  5 . In the case of a horizontal fitting position of a selection button provided with two switching positions, finger-grip knob  10  will assume a vertical resting position (0°) in the one engagement position, and a rotated position which is angularly offset therefrom (for example, +30°) whereas, in the other engagement position, the finger-grip knob will assume a resting position which is angularly offset with respect to the vertical (for example, −15°) and a rotated position which is symmetrically angularly offset therefrom (for example, +15°). 
   When using key actuator  2  as a handle, the selection button can be provided with three switching positions again. In this variant, modified first transmission member  4 ′ shown in  FIG. 1  is used whose switching cam elements  42  and fourth counterstops  47  are formed identically as in above described first transmission member  4 . Without a latching slide, the latching actuation mode is implemented again, the full angle of rotation being reached here, allowing key  21  to be released or removed in the rotated positions. To dimension the full angle of rotation in both directions, provision is made for a third stop device including two diametrically opposing third stops  28  which are formed on the rear side of stationary cylinder lock  22  as ring segments and in an axial direction, and of two diametrically opposing third counterstops  48 ′ which are formed on front side  44 ′ of modified first transmission member  4 ′ in a nose-shaped manner and directed radially inward, corresponding radially and axially running side faces  281  of third stops  28  cooperating with corresponding side faces  481 ′ of third counterstops  48 ′. 
   In this case, fourth counterstops  47  of first modified transmission member  4 ′, together with second stop faces  95  of second stop slides  92  which are inserted in housing  6 , form the fifth stop device for implementing the momentary contact actuation mode. Because of the limited angle of rotation, it is not possible for key  21  to be removed in the rotated positions. 
   By inserting first stop slides  91  in lieu of second stop slides  92 , provision is made for fourth stop device which, when key actuator  2  is rotated out of the resting position, are effective already before the third stop device but after the above described fifth stop device. In this manner, again, a latching actuation mode is implemented, however, due to the still limited angle of rotation, key  21  cannot be removed in the rotated position here either since it is retained in cylinder lock  22  because of the failure to reach the full angle of rotation. The fourth stop device includes mutually opposing first stop faces  94  which are formed by the in each case rear surface of a notch  97  located at the front part of narrow side  96  of first stop slides  91  which narrow side opposes the respective direction of rotation, and of fourth counterstops  47  of modified first transmission member  4 ′. The two stop slides  91  have a mirror-symmetric design with respect to their narrow sides  96  as axis of symmetry and differ from second stop slides  92  basically by notches  97 . One of the two first stop slides  91  is coded at the rear part with a first indentation  99  which corresponds to a second indentation  71  underneath one of mating latching devices  64  in housing  6  to enable each of the two mirror-symmetric fist stop slides  91  to be placed to the correct location of housing  6 . 
   When using key actuator  2  as a handle, the selection button can also be provided with two switching positions. In this embodiment, modified second transmission member  5 ′ shown in  FIG. 1  is used whose switching cam elements  52 , second counterstops  59 , and fourth counterstop  57  are formed identically as in above described first transmission member  4 . Again, key  21  is released in the rotated position with no latching slide being inserted. In the case of a latched rotated position and releasable key  21 , again, the movement is limited by the third stop device, which includes third stops  28  located at cylinder lock  22  and by third counterstops  58 ′, which are formed on front side  54 ′ of modified second transmission member  5 ′ and which correspond to counterstops  48 ′ of modified first transmission member  4 ′. Here too, the limiting in the resting position is brought about by the sixth stop device including fourth stops  70  in housing  6  and second counterstops  59 . 
   By inserting only one first stop slide  91  into housing  6 , in cooperation with fourth counterstop  57  of modified second transmission member  5 ′, again, provision is made for the fourth stop device which, in cooperation with cylinder lock  22 , retain key  21  in the latched rotated position. 
   Here too, the limitation of the rotary motion in the momentary contact actuation mode is carried out by the fifth stop device including the only second stop slide  92  and fourth counterstop  57 . 
   The present invention is not limited to the specific embodiments described above but includes all equally-acting embodiments along the lines of the present invention. Instead of the described handles, it is also possible to use other equally-acting handles such as an actuating rod which is appropriately formed at the end face and capable of being directly engaged with recesses  43 ′ or  53 ′ of modified first or second transmission member  4 ′ or  5 ′ from the front and able to be removed therefrom again. In the case of a selection button provided with three switching positions, it is also possible to use only one first stop slide  91  alone, one second stop slide  92  alone or one first and one second stop slide  91  and  92  together to implement the latching or momentary contact actuation mode only in only one corresponding direction of rotation, possibly with releasable or retained key. Simplified embodiments of the present invention can be provided for certain applications by using only one switch plunger  81 . A simplification at the cost of reliability can also be achieved in that in each case only one first, second and third stop  66 ,  68  or  28 , respectively, may be provided. 
   LIST OF REFERENCE NUMERALS 
   
       
         10  finger-grip knob 
         11  rotary knob 
         12  rib segments 
         13  guide collar 
         14  first counterstop 
         15  side face 
         2  key actuator 
         21  key 
         22  cylinder lock 
         23  cover 
         24  noses 
         25  lock core 
         26  formations 
         27  retaining collar 
         28  third stop 
         281  side face 
         29  recess 
         3  front ring 
         4  first transmission member 
         40  seals 
         41  rear side 
         42  switching cam elements 
         43  slot segments 
         44  front side 
         45  light aperture 
         46  cam tip 
         47  fourth counterstop 
         471  edge face 
         4 ′ modified first transmission member 
         43 ′ recesses 
         44 ′ front side 
         48 ′ third counterstop 
         481 ′ side face 
         5  second transmission member 
         51  rear side 
         52  switching cam elements 
         53  slot segments 
         54  front side 
         55  light aperture 
         56  cam tip 
         57  fourth counterstop 
         571  edge face 
         59  second counterstop 
         591  edge running ahead 
         592  edge running after 
         5 ′ modified second transmission member 
         53 ′ recesses 
         54 ′ front side 
         58 ′ third counterstop 
         6  housing 
         61  guide strips 
         62  second abutment 
         63  grooves 
         64  mating latching means 
         65  guide groove 
         66  first stop 
         67  side face 
         68  second stop 
         69  recess 
         70  fourth stop 
         71  second indentation 
         81  switch plunger 
         82  pressure spring 
         83  outer edges 
         84  first abutment 
         85  third abutment 
         86  end face 
         87  slanted surface 
         88  latching recess 
         91  first stop slide 
         92  second stop slide 
         93  latching means 
         94  first stop face 
         95  second stop face 
         96  narrow side 
         97  notch 
         98  narrow side 
         99  first indentation