Abstract:
A device with a key-actuated closing cylinder and a switch triggers, when a key is turned therein, a particular electric function in a motor vehicle. In order to achieve a particularly compact and reliable device, at least two sensors are arranged inside the cylinder housing of the closing cylinder in zones that are mutually offset in the longitudinal direction. The sensor outputs are connected to a common evaluation device. The cylinder core has in corresponding axial zones several permanent magnets at particular points of its periphery. These points are selected so that the evaluation device detects different codes at the sensor outputs in the different working positions of the cylinder core and clearly identifies with these codes the corresponding working positions. The evaluation device thus acts as an electronic switch which on the basis of the sensed code triggers the electric function that corresponds to the momentary working position.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention pertains to a device with a key-actuatable lock cylinder and with a switching device, which, as a function of the rotation of the key, activates or deactivates certain electrical functions in a motor vehicle or the like, especially an ignition starter switch for a motor vehicle, where the lock cylinder consists of a stationary cylinder housing and a cylinder core, which is supported in the housing with freedom of rotation, which—starting from an original rotational position—is moved by the turning of the key into one of several defined working positions, in which the switching device initiates an electrical function in the motor vehicle or the like, which function is specific to the working position in question; where, in addition to tumblers for blocking the rotation of the cylinder core in the cylinder housing, a key channel to accept the key for unlocking the cylinder core is provided in the interior of the cylinder core; where permanent magnets are provided on the circumference of the cylinder core; and where, in addition to at least one locking channel for the tumblers, sensors responding to the permanent magnets of the cylinder core are also provided in the cylinder housing. The lock cylinder consists of a stationary cylinder housing and a cylinder core supported in the housing with freedom to rotate. The key can be inserted and removed from its key channel only in a certain original rotational position of the cylinder core. By turning the key, the cylinder core can be brought into certain defined rotational positions, which are to be referred in brief below as “working positions”. In these working positions, certain electrical functions in the motor vehicle or in some other useful object are activated or deactivated by way of the switching device. 
     2. Description of the Related Art 
     When a device such as this is used in motor vehicles, it serves as a so-called “ignition starter switch”. In the known device, the switching device has both a contact element which turns along with the turning of the key and stationary contacts, which are connected electrically to the given on-board electrical system. This device is located at the inner end of the lock cylinder. The movable switching element is connected in a torsionally rigid way to the cylinder core. In the working positions, the movable contact element becomes electrically connected to the stationary contact to which the system responsible for the desired function in the motor vehicle is connected. In the case of an ignition starter switch, there are usually three working positions besides the original rotational position. These include a first working position for switching on the electrical system of the vehicle, a second working position for releasing the internal combustion engine present in the vehicle for ignition, and a third working position for starting the engine. 
     The switching device in the known device occupies a considerable amount of space, and the space it occupies is then no longer available for other important components of the motor vehicle. In the known ignition starter switch, the switching device is installed at inner end of the lock cylinder. Thus the ignition starter switch is usually installed near the steering column of the motor vehicle, where it also has other duties to fulfill. These include the locking of the steering column after the key has been removed. Problems are encountered when the elements of the switching device are contacted mechanically. The angular distances between the working positions of the cylinder core initiating the various functions can be very small, for which reason the distances between the contacts in the switching device can be distinguished reliably only when a sufficient amount of space is available in the radial direction for the movement of the movable switching element from one angular position to the other. In addition, for safety reasons alone, a minimum amount of space must be provided for the switching device. All of this increases the space requirement. 
     There are locks (U.S. Pat. No. 5,186,031) in which a permanent magnet is installed on the circumference of the cylinder core. When the cylinder is turned by the key, an electronic monitoring function takes place by way of a sensor integrated into the cylinder housing; this sensor responds to the magnetic field of the cylinder core turning past it. As a result, the electrical system of the motor vehicle is turned on, and only then can the above-described switching device be activated. If the lock cylinder is forcibly torn out, electrical manipulations of the contacts are therefore useless. Unless the switching device is activated by way of the permanent magnet, which must be moved past the sensor, the switching device remains off-line. It therefore did not appear that there was any way to reduce the space requirement in the design of the known device. 
     In another device (U.S. Pat. No. 5,455,571), the attempt was made to make it more difficult for unauthorized persons to read the activation signal. This attempt took the form of a second sensor, which acts on the signal output of the addressed first sensor. The goal of this measure was to prevent outsiders from determining the signal value. 
     SUMMARY OF THE INVENTION 
     The invention is based on the task of developing a reliable device of the aforementioned kind which is simple and compact. This is accomplished in accordance with the invention by the following measures: the cylinder housing carries at least two sensors in zones which are axially offset from each other in the longitudinal direction, the sensor outputs of these sensors being connected to a common evaluator; in the corresponding axial zones, the cylinder core has several permanent magnets at the circumferential points which, in cooperation with the sensors, transmit to the sensor outputs an electrical coding which differentiates the original rotational position and the various working positions of the cylinder core; and the evaluator not only uniquely identifies the original rotational position and the working position of the cylinder core in question by way of the code but also—on the basis of the code which has been determined—initiates the electrical function in the motor vehicle or the like belonging to this working position. 
     The permanent magnets in the cylinder core cooperate with the sensors in the cylinder housing to encode all the defined working positions of the cylinder core. By way of the sensors, therefore, the specific working position of the cylinder core at the time in question can be uniquely identified, and this information can be sent to an evaluator, which then simultaneously acts as an electronic switch and initiates the individual electrical functions in the motor vehicle or other useful object. Whereas, in the state of the art, the rotational position is detected on the basis of an element of the switching device which moves along with the cylinder core, it is, in the invention, the job of the stationary sensors in the cylinder housing to identify the rotational positions. The code-controlled evaluator for the code-specific electrical functions is connected to the read-out points in the cylinder housing by signal lines of small diameter and can thus be installed at a point any desired distance away. 
     Because the components which bring about the desired electrical function are now electronic and no longer mechanical, it is also possible to produce the switching device in the device according to the invention in an extremely compact and inexpensive manner. The device according to the invention requires only that holes be provided in the cylinder housing to accept the sensors which read the code. The permanent magnets in the cylinder core can also be countersunk in holes at the points on the circumference which determine the coding. This means that, in the device according to the invention, the lock cylinder does not need to occupy any more space than it does in the state of the art, but also that the space at the inner end of the lock cylinder, where previously the switching device was located, can now be used for something else. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     Additional measures and advantages of the invention can be derived from the subclaims, from the following description, and from the drawings. The invention is illustrated in the drawings on the basis of an exemplary embodiment: 
     FIG. 1 a  shows a partial, longitudinal cross section through the lock cylinder of the device according to the invention in the original rotational position of the cylinder core, before the key has been inserted; 
     FIGS. 1 b  and  1   c  show cross sections through the lock cylinder according to FIG. 1 a  along lines I b —I b  and I c —I c;    
     FIG. 2 a  shows a longitudinal cross section of the lock cylinder corresponding to FIG. 1 a , again in the original rotational position, but this time with the key inserted; 
     FIG. 2 b  shows the cross section already presented in FIG. 1 b  in the original rotational position but after the key has been inserted; 
     FIGS. 3 a,    4   a,  and  5   a  show longitudinal cross sections similar to FIG. 1 a  after the cylinder core has been moved by the inserted key into the three additional rotational positions, which correspond to the “ON” position of the vehicle&#39;s electrical system, to the ignition position of the engine, and to the starting position of the engine; 
     FIGS. 3 c,    4   c,  and  5   c  show cross sections through the lock cylinder corresponding to FIG. 1 b  after the cylinder core has been moved into the three additional rotational positions according to FIGS. 3 a,    4   a,  and  5   a;    
     FIGS. 3 c,    4   c,  and  5   c  show additional cross sections through the lock cylinder in analogy to FIG. 1 c  after the key has rotated the core into the positions of FIGS. 3 a,    4   a,  and  5   a;    
     FIG. 6 shows a code table of the signals being received in the various rotational positions of FIGS. 1 a - 5   c;    
     FIG. 7 shows a schematic circuit diagram of an evaluator for the signals being received in the original rotational position of FIGS. 2 a  and  2   b  and for the working positions of FIGS. 3 a - 5   c;  and 
     FIG. 8 shows part of a second embodiment of the lock cylinder according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The device according to the invention comprises a lock cylinder  10  according to FIGS. 1 a  to  5   c  and also an electronic evaluator  20 , the basic design of which is illustrated in FIG.  7 . Lock cylinder  10  itself, however, includes not only mechanical but also electrical components. 
     The lock cylinder consists of a cylinder core  11  and a cylinder housing  12 . Whereas cylinder housing  12  is mounted permanently in a chassis  30  of a motor vehicle, cylinder core  11  is supported so that it can rotate in housing  12 . The cylinder core has interior chambers for conventional, spring-loaded tumblers  13 , only one of which is indicated in FIG. 1 a.  Cylinder housing  12  has locking channels in the usual manner (not shown), in which tumblers  13  are normally engaged to prevent the rotation of cylinder core  11  in the direction of arrow  14  of FIG. 1 a  around cylinder axis  15  indicated in dash-dot line. Cylinder core  11  also has a key channel  16 , visible in FIGS. 1 b  and  1   c,  which, as can be seen in FIGS. 2 a  and  2   b,  serves to accept a key  17  as needed, and finally a radial chamber  18 , in which a slider  31  is installed, which is acted on by the force  32  of a spring  33 . 
     FIGS. 1 a - 1   c  show the original rotational position of cylinder core  11 . This rotational position is illustrated by auxiliary line  50  in FIG. 1 b.  In this case, a locking bar  40  has moved radially outward, and its outer working end  42  is engaged in a housing groove  43 ; it acts like a tumbler and blocks the rotation of cylinder core  11  as shown in FIG. 1 b.  Locking bar  40  is in its “locking position” in FIGS. 1 a - 1   c.  When a properly-fitting key  17  is inserted into key channel  16  as shown in FIGS. 2 a  and  2   b,  control surfaces  37  provided on the profile of the key sort out the above-mentioned tumblers  13  along the cross section of cylinder core  11 , which has the effect of releasing cylinder core  11 ; in addition, however, slider  31  is also pushed back against spring force  32  acting on it into the position which can be seen in FIG. 2 b,  where a recess  34  provided in slider  31  comes into alignment with the control end  41  of locking bar  40 . 
     FIG. 2 b  shows the same original rotational position  50  of cylinder core  11  as FIG. 1 b  does, as can be seen from the rotational position of locking bar  40 . Locking bar  40  is also spring-loaded in the direction of arrow  44 . The spring responsible for this is not shown in detail in the figures. While the previously mentioned radial alignment is present, therefore, control end  41  of locking bar  40  can travel into recess  34 . Then working end  42  of the locking bar is disengaged from housing groove  43 . When key  17  is inserted, therefore, the blockade caused up until now by locking bar  40  is eliminated; the locking bar is now in its “release position”, and cylinder core  11  can be rotated by the key in the direction of arrow  14 . Depending on the extent of this rotation  14 , cylinder core  11  arrives in one of three defined rotational positions  51 ,  52 ,  53 , which trigger certain electrical functions in the device according to the invention and therefore, as already said above, should be referred to as “working positions”. For reasons of clarity, these working positions are arranged not only at the same distances but also at exaggeratedly large angular distances from each other, as illustrated by auxiliary lines  51 ,  52 ,  53 . The location of these auxiliary lines is derived from the specific rotational position of the locking bar at the time. 
     The present exemplary embodiment is based on the so-called ignition starter switch of a motor vehicle. Only when its cylinder core  11  is in the original rotational position  50  of FIGS. 1 a - 1   c  is it possible for key  17  to be inserted into key channel  16 , as illustrated in FIGS. 2 a  and  2   b,  or for it to be pulled back out again. That is, it is only in this original rotational position  50  that tumblers  13  are aligned radially with the above-mentioned locking channels in housing  12  and allow themselves to be moved in the radial direction. In original rotational position  50 , the electrical system of the motor vehicle remains “off” until a properly fitting key is inserted. In the present invention, as long as a properly fitting key  17  has not been fully inserted into cylinder core  11 , that is, in the situation according to FIGS. 1-1 c,  evaluator  20  also remains off-line. The evaluator is dead and unable to accomplish any electrical control functions whatever, even if an attempt is made to manipulate the power supply. By insertion of key  17  according to FIGS. 2 a  and  2   b,  however, the evaluator is “activated” according to the invention and can be used for the other functions. This is accomplished in the present invention by means of a special design of locking bar  40 . 
     That is, in the device according to the invention, locking bar  40  consists of magnetic material  45 , which makes locking bar  40  into a radially movable “permanent magnet”. The use of magnetic material  45  in locking bar  40  is indicated by light dotted shading in the drawings. A first sensor H 1 , which is mounted in a suitable socket  35  in cylinder housing  12 , is assigned to this permanent magnet  40 . Sensor H 1  is a Hall-effect device, which is located in the zone of cylinder housing  12  indicated by the number  38  in FIG. 1 a.  Another socket  36  for an additional sensor H 2  in cylinder housing  12  is provided a certain axial distance  29  away; this sensor is also a Hall-effect device. The positions of these two sensors H 1 , H 2  are drawn in FIG. 1 a  in dash-dot lines, from which their locations in the two housing zones  38 ,  39  can be derived. In original rotational position  50 , no magnet is present at sensor H 2 , as can be derived from FIG. 1 c.  The two sensors H 1 , H 2  with their outputs  21 ,  22  are connected to the same evaluator  20  according to FIG.  7 . When locking bar  40  is in its radially outward position shown in FIG. 1 b,  the evaluator detects its magnetic field over sensor output line  21  from H 1  but does not detect any signal on output line  22  from H 2 . This situation is recognized by evaluator  20  as a defined code, which in this case keeps the on-board electronic system off-line. This situation, a “yes/no” code, appears in the top line of the code table shown in FIG.  6 . 
     When key  17  is inserted according to FIGS. 2 a  and  2   b,  locking bar  40  now arrives in its previously described release position, in which the distance between it and Hall generator H 1  is greater. As a result, the magnetic field detected by sensor H 1  is significantly decreased, and this is interpreted by the evaluator as “zero signal”. Evaluator  20  does not detect any signal from sensor H 2  either. This situation is indicated in the second line of the code table of FIG.  6 . The transition of the original code “yes/no” according to FIGS. 1 a - 1   c  to the code “no/no” of FIGS. 2 a,    2   b  allows evaluator  20  to conclude that a properly fitting key has been inserted. Evaluator  20  now transmits an appropriate signal along a data line to activate the corresponding systems in the motor vehicle, such as an on-board computer, which directs appropriate control units such as an anti-theft device. Although this is shown in FIG. 7 by a first output line  23 , this could also be accomplished by way of a common bus line replacing all of output lines  23 - 26 . The bus line would then transmit the digital data generated by the evaluator on the basis of the code to a central electrical unit in the motor vehicle. Evaluator  20 , according to FIG. 7, is provided with a power supply  27  and is grounded by a line  28 . 
     As indicated by the cross sections of FIGS. 1 b  and  1   c,  additional permanent magnets  55  are provided in corresponding axial zones  58 ,  59  of cylinder core  11 ; these magnets cannot move in the radial direction as locking bar  40  can; instead, they are mounted immovably in suitable recesses  54  in the circumferential surface. Permanent magnets  55  can thus be flush with the circumference of cylinder core  11 . These permanent magnets  55  are indicated in the drawings by dotted shading. In the given design of lock cylinder  10 , permanent magnets  55  have a somewhat stronger magnetic field strength than magnetic material  45  of which locking bar  40  is made. This is indicated in the drawings by the different degrees of shading. In the present case, two of these stationary permanent magnets  55  are provided in each of the two axial zones  58 ,  59 , namely, at defined points  46 ,  47 ,  48 ,  49  on the circumference of the cylinder core  11 , to be described in greater detail below. These locations are selected in correspondence with the angles of rotation between the original rotational position  50  and the three additional working positions  51 ,  52 ,  53 , as can be derived from a consideration of the additional FIGS. 3 a - 5   c.    
     In FIGS. 3 a - 3   c,  the turning  14  of the key has moved cylinder core  11  to first working position  51 . If the device has been incorporated into an ignition starter switch, the electrical system of the vehicle is turned on in this position. This working position  51  is also called the “radio position”. In the case of an ignition starter switch, we speak of power being supplied to “terminal R” of the associated switching device in this working position  51 . Working position  51  of cylinder core  11  is held by latching elements (not shown in detail) and can be felt as the key is being turned  14 . In this rotational position, locking bar  40  is even farther away from sensor H 1 , for which reason this sensor, as can be derived from the third line of the code table of FIG. 6, transmits no signal to evaluator  20 . In the adjacent axial zone  59  of cylinder core  11 , however, a permanent magnet  55  has become radially aligned with sensor H 2 . This permanent magnet  55  is located at a circumferential point  48  of this zone  59  which, upon rotation into working position  51 , is near sensor H 2 . By way of sensor output  22 , evaluator  20  receives a signal, as can be seen from the third line of the code table of FIG.  6 . Upon receiving this code “no/yes”, evaluator  20  uniquely determines that cylinder core  11  is in this first working position  51 . Because the evaluator acts like an electronic switch, it issues the corresponding control commands to the appropriate systems or to the on-board computer controlling these systems. This is shown in FIG. 7 in that now a control signal is transmitted over second output line  24 . In technical language, it is said that “terminal R” has been activated. 
     In FIGS. 4 a - 4   c,  cylinder core  11  has been turned even farther in the direction of arrow  14  so that it has now arrived at second working position  52 . Additional permanent magnets  55  are located in the two axial zones  58 ,  59  of the cylinder core at the circumferential points identified as  47  and  49 , which are then oriented toward the two sensors H 1 , H 2  in cylinder housing  12 . This working position  52  is also identified by latching elements, the effects of which are perceptible during rotation  14  of key  17 . Evaluator  20  in this case detects a signal at both sensor outputs  21 ,  22 , as indicated in the fourth line of the code table of FIG.  6 . When it receives this code “yes/yes”, evaluator  20  identifies the working position of cylinder core  11  as the second working position and transmits a corresponding control signal to the systems of the motor vehicle which are now to be put into action. In the case of an ignition starter switch, this second working position is usually responsible for releasing the engine for ignition. This is symbolized in the diagram of FIG. 7 by a third output line  25 , which is now active. In the case of an ignition starter switch, it is traditional to speak in this working position of supplying “terminal  15 ” of the switching device with electrical current. 
     In FIGS. 5 a - 5   c,  cylinder core  11  has been turned in the direction of arrow  14  so far that it has now reached a third defined working position  53 . This third working position  53  can be determined by a rotational end-stop acting on the cylinder core  11 . In this case, a permanent magnet  55  is located only on circumferential point  46  in axial zone  58  of cylinder core  11  belonging to sensor H 1 , whereas, in the other axial zone  59 , an empty circumferential point of cylinder core  11  appears. As a result, only the first sensor H 1  detects a signal, which arrives via sensor output  21  at evaluator  20 . Sensor H 2  does not transmit any signal. Evaluator  20  thus establishes in this case the code “yes/no” according to the last line of the code table of FIG.  6 . 
     A code such as this has already been obtained in the first line of FIG. 6, which has been described on the basis of FIGS. 1 a - 1   c.  There, however, cylinder core  11  was still in the original rotational position, in which evaluator  20  was still off-line. There, key  17  had still not been inserted, and cylinder core  11  was blocked by locking bar  40 . In the case of FIGS. 5 a - 5   c,  however, evaluator  20  is now active and therefore identifies this code “yes/no” clearly as the third working position of cylinder core  11 . When the device is applied to an ignition starter switch, this position usually corresponds to the electrical “start the engine” function of the associated switching device, in which the internal combustion engine in the motor vehicle is started. It is said in this case that “terminal  50 ” has been activated. In the present invention, evaluator  20  activates a fourth output line  26  in the diagram of FIG.  7 . 
     In this case, evaluator  20 , acting as an electronic switching device, activates the starter of the motor vehicle. Normally, cylinder core  11  of an ignition starter switch is under the action of a rotational pulse spring, which, after the release of key  17 , tries to push cylinder core  11  back into the second working position of FIGS. 4 a - 4   c.  This latter situation, too, is recognized by evaluator  20  on the basis of the resulting change in the code to “yes/yes” in FIG.  6 . 
     FIG. 8 shows an alternative design of a lock cylinder according to the invention  10 ′, only a small part of which is illustrated. The difference from the previously described first exemplary embodiment consists in that, in each axial zone  38  where a sensor H 2  is seated in the cylinder housing, a ring or a ring segment  56  of magnetizable material is provided in cylinder core  11 ′. This material is subjected to polarizing magnetization at the circumferential points of cylinder core  11 ′ where permanent magnets  55 ′ detectable as a code are wanted, as shown in FIG.  8 . Then sensor H 2  detects the magnetic field at defined sections  57  of the ring, and evaluator  20  again determines from that signal the working positions in question on the basis of the code. Ring section  57  acting as permanent magnet  55 ′ in FIG. 8 is illustrated by dotted shading. FIG. 8 shows the radial alignment of this ring section  57 , made relevant by magnetization, with sensor H 2 . This corresponds to the first working position of cylinder core  11 ′ shown in FIGS. 3 a - 3   c.    
     The design of lock cylinder  10 ′ according to FIG. 8 makes it possible, first, to prefabricate all the cylinder cores, regardless of the desired code. Permanent magnets  55 ′ corresponding to the individual encoding of the rotational positions of cylinder core  11 ′ are then provided by subjecting the appropriate sections  57  of the ring to magnetization  55 ′. It would also be possible to magnetize the defined sections  57  of the rings or ring segments  56  before their installation in cylinder core  11 ′. 
     It is obvious that a different number of sensors H 1 , H 2  and a different arrangement of them could also be used, if appropriate for a specific application. This also applies to the number and position of the permanent magnets. If needed, it would also be possible to omit the use of a locking bar  40  which can be moved radially by key  17  or to not make this locking bar  40  out of magnetic material  45 . Because of its magnetic material  45 , locking bar  40  in the present invention signal to evaluator  20  whether or not the correct key has been inserted in cylinder core  11 . This is used to activate and deactivate evaluator  20 , the on-board computer, or the central electrical system. The magnetic field strength of the individual permanent magnets  55  or of permanent magnets  55 ′ arising at certain points by magnetization could have magnetic field strengths which are different from each other or a different magnetic field orientation, which could be detected by sensors H 1 , H 2  and then evaluated. By means of these measures, the number of possible code variants would be significantly increased. One could then provide enough information merely in axial zone  38  and/or  39  by the use of different magnets  55  or magnetizations  55 ′ in terms of the orientation and/or strength of the magnetic fields to make it possible for a single sensor H 1  or H 2  to determine the individual working position  51 ,  52 ,  53  in question of cylinder core  11  or  11 ′. In this case, the only factors which vary are the number of sensors and the differences between the permanent magnets at the specific circumferential points of cylinder core  11  or  11 ′. 
     In the device according to the invention, no components for a switching device to be controlled by lock cylinder  10  are required at inner end  19  of the lock cylinder shown in FIG. 1 a.  This space is therefore now available for the installation of other important components of the motor vehicle. 
     LIST OF REFERENCE NUMBERS 
     H 1  first sensor, Hall-effect device 
     H 2  second sensor, Hall-effect device 
       10 ,  10 ′ lock cylinder 
       11 ,  11 ′ cylinder core of  10 ,  10 ′ 
       12  cylinder housing of  10   
       13  tumbler in  11   
       14  rotation arrow of  11   
       15  cylinder axis of  10   
       16  key channel in  11   
       17  key 
       18  radial chamber for  31   
       19  inner end of  10   
       20  evaluator 
       21  sensor output of H 1   
       22  sensor output of H 2   
       23  first output line of  20   
       24  second output line of  20   
       25  third output line of  20   
       26  fourth output line of  20   
       27  electric power line of  20   
       28  ground lead of  20   
       29  longitudinal offset between H 1 , H 2 , in  12   
       30  chassis for  10   
       31  slider 
       32  arrows of the force acting on  31   
       33  spring for  32   
       34  recess in  31  for  41   
       35  socket in  12  for H 1   
       36  socket in  12  for H 2   
       37  control surface on  17  for  13 ,  31   
       38  axial zone in  12  for H 1   
       39  axial zone in  12  for H 2   
       40  locking bar 
       41  control end of  40   
       42  working end of  40   
       43  housing groove of  42   
       44  force arrow for the spring-loading of  40   
       45  magnetic material of  40   
       46  first circumferential point in  11  at  58   
       47  second circumferential point in  11  at  58   
       48  first circumferential point in  59  of  11   
       49  second circumferential point in  59  of  11   
       50  original rotational position of  11   
       51  first working position of  11  (radio) 
       52  second working position of  11  (ignition) 
       53  third working position of  11  (starting) 
       54  recess for  55  in  11   
       55 ,  55 ′ permanent magnet in  11 ,  11 ′ 
       56  ring, ring segment 
       57  magnetizable ring section of  56   
       58  first axial zone of  11  for  40 ,  55   
       59  second axial zone in  11  for  55