Abstract:
The invention concerns a canceling device ( 10 ) for a blinker switch in motor vehicles for effecting automatic return of the blinker switch from one of the two switched positions into the neutral central position. Towards this end, a casing ( 12 ) having a catch profile ( 14 ) is provided as is a movable pretensioned trigger finger ( 16 ) which can be loaded by the cam ( 128 ) of a steering shaft ( 44 ) and with a pivotable switching part ( 26 ) having pretensioned catch elements ( 62, 64 ). To reduce the actuating forces, the catch profile ( 14 ) is provided with a movable locking section ( 54, 56 ). The trigger finger ( 16 ) should be connected to the movable locking section ( 54, 56 ) such that the locking section ( 54, 56 ) releases the catch element ( 62, 64 ) when the trigger finger ( 16 ) is actuated.

Description:
[0001]    This application claims Paris Convention priority of DE 100 37 586.3 filed Aug. 2, 2000 the entire disclosure of which is hereby incorporated by reference 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention concerns a canceling device for a blinker switch in motor vehicles which effects automatic canceling of the blinker switch from one of the two switched positions into the neutral central position, comprising a casing with at least one catch profile, and having a movable pretensioned trigger finger which is disposed in the switched positions such that it can be actuated by a cam connected to a steering shaft, and comprising a switching piece which is pivotable and equipped with at least one pretensioned catch element engaging in the catch profile.  
           [0003]    A canceling device of this type has been commercially available. When the blinker switch is switched on, the switching piece releases the trigger finger which is caused, due to its pretension, to move radially inward towards the steering shaft and projects into a circular path of the cam connected to the steering shaft. The switching piece is held in the switched position by a pretensioned catch element engaging in a depression of the catch profile.  
           [0004]    When, during a corresponding turning motion of the steering wheel, the cam connected to the steering shaft is moved past the trigger finger, the trigger finger is pivoted sidewardly. Carrier surfaces provided on the trigger finger thereby engage a shoulder of the catch element to pull same, in opposition to its direction of pretension, out of the depression in the catch profile. The switching piece together with the blinker switch can thereby snap back into their neutral central positions.  
           [0005]    The forces required for actuating the trigger finger in the known canceling device are relatively large. This does not provide a problem for the user turning the steering wheel, who cannot feel this force due to the very favorable lever conditions. The large forces which occur during actuation cause, however, different problems: In many modern vehicles, a steering angle sensor is also disposed in the region of the canceling device which is used for electronic determination of the steering angle. The signals provided by the steering angle sensor are used e.g. by an electronic stabilization device for the vehicle. The reliability of the signals provided by the steering angle sensor is therefore very important. To reduce the amount of space needed and the number of required parts, the canceling device for the blinker switch and the steering angle sensor are often mounted to a common support.  
           [0006]    The large forces which occur at the canceling device during its actuation can deform the support to which the canceling device and the steering angle sensor are mounted. These deformations falsify the signals provided by the steering angle sensor.  
           [0007]    It is therefore the underlying purpose of the present invention to further develop a canceling device of the above-mentioned type such that the forces produced during actuation of the trigger finger are reduced.  
         SUMMARY OF THE INVENTION  
         [0008]    This object is achieved in a canceling device of the above-mentioned type in that the catch profile has at least one movable locking section and the trigger finger is connected to the movable locking section such that the locking section releases the catch element when the trigger finger is actuated.  
           [0009]    In accordance with the invention, for automatic canceling of the blinker switch, the catch element is not returned in opposition to the pretensioning force but rather the path which the catch element must follow between the switched position to the neutral central position “is cleared”. The forces which are required for moving the locking section are much smaller than those of prior art which were required to move the catch element in opposition to the spring force. In theory, only the frictional force between the locking section and the catch element must be overcome. For this reason, the deformations to which the canceling device and the carrier connected therewith are subjected during actuation from one of the two switched positions into the neutral central position are very small which considerably improves the measuring accuracy of a steering angle sensor disposed on the same carrier.  
           [0010]    Advantageous embodiments of the invention are given in the dependent claims.  
           [0011]    A locking section which is easy to realize is formed in a further development of the invention on a part which can be pivoted like a door. Alternatively, the locking section can also be formed on a linearly displaceable part.  
           [0012]    A deflecting element can preferably be provided to transfer the actuating motion of the trigger finger to the locking section. A deflecting element of this type can convert the direction of motion of the trigger finger in a simple fashion such that the locking section can be moved in any direction required e.g. by installation considerations. In addition, such a deflecting element permits realization of various lever arms for changing forces or stroke lengths.  
           [0013]    In a preferred further development of the inventive canceling device, the deflecting element comprises a slot in the region facing the locking section whose longitudinal axis is disposed at an angle with respect to the direction of motion of the locking section, wherein the locking section is connected to a pin which engages the slot. The movement of such a deflecting element can be transformed into a motion of the locking section in a simple fashion.  
           [0014]    A further development is particularly preferred wherein the locking section is kinematically locked in its locked position. This type of kinematic locking can be effected without a spring element, the load of which would have to be overcome during motion of the locking section. With such a restoring device, the movement of the locking section into a position in which the catch element is released requires very little force.  
           [0015]    An example of such kinematic locking of the locking section is effected when the longitudinal axis of the slot is bent and the longitudinal axis of that region of the slot containing the pin of the locking section in the neutral central position is substantially at right angles with respect to a radius line intersecting the axis of rotation of the deflecting element and that region.  
           [0016]    When the blinker switch is in the neutral central position, the locking section is in a position in which the catch element is arrested in its central position. In this neutral central position, the described geometrical arrangement allows the locking section to only transfer forces to the deflecting element whose line of action passes through the axis of rotation of the deflecting element. The corresponding lever arm is equal to zero such that loading of the locking section does not move the deflecting element and the locking section remains locked. Only a motion of the deflecting element moves the pin of the locking section into the other region of the slot in which the mechanism is unlocked.  
           [0017]    An alternative to the angled slot is given in a further development, wherein the deflecting element comprises a stepped slot in its section facing the locking section into which a pin, connected to the locking section, engages. Such an embodiment is particularly preferred when the locking section is formed on a linearly displaceable part. The inventive canceling device can comprise at least one tensioning element which loads the deflecting element into its neutral central position. In connection with a purely kinematic locking of the locking section, the force required for actuating the trigger finger is substantially given by the tensioning force of this tensioning element. Since this can be very small, the required actuating force is also correspondingly small.  
           [0018]    The tensioning element can thereby comprise a helical pressure spring whose one end is received in a sleeve having a closed end which is rounded or semi-spherical, wherein the closed end of the sleeve is preferably received in a corresponding depression in the casing. In this further development, the helical pressure spring can be oriented in correspondence with the position of the deflecting element. The depression is thereby preferably also rounded and dimensioned such that a corresponding pivoting motion of the sleeve and simultaneously of the helical pressure spring is possible.  
           [0019]    To improve engagement of the tensioning element on the deflecting element, the invention also provides the deflecting element with a pin-like shoulder which the tensioning element surrounds at its free end, or a recess into which the tensioning element engages.  
           [0020]    To secure the trigger finger against tilting, the trigger finger can be further provided with at least one supporting wing for support on the deflecting element.  
           [0021]    In a further development of the invention, the casing comprises a wall element which is provided with a guiding slot which extends parallel to the longitudinal axis of the trigger finger, into which a guiding pin of the trigger finger engages and/or at least one guiding slot into which a guiding pin engages which is disposed on a section of the deflecting element. Such guiding slots guide the trigger finger and/or the deflecting element to ensure even more accurate motion of the corresponding elements.  
           [0022]    The guiding slot can thereby constitute a stop for the path of motion of the trigger finger or of the deflecting lever. Such a stop can e.g. delimit the maximum linear motion of the trigger finger out of the casing. The final positions of the deflecting lever can likewise be defined in a simple fashion.  
           [0023]    The forces which are required to move the switching piece from its neutral central position into one of the switched positions, can be reduced if the catch element comprises a rotatable roller on its end facing the catch profile. It is, of course, also possible to provide a ball-shaped or a similar element instead of a roller, which turns along the catch profile, with little friction, during motion of the catch elements. The wear on the catch profile and on the catch element in the region of the contact surfaces is thereby also reduced.  
           [0024]    The catch profile can furthermore comprise a canceling section having a step which must be overcome when actuating the catch element into the switched position. Such a step produces a defined engaged position which the user can feel when engaging the blinker switch.  
           [0025]    One further development of the invention is particularly preferred, wherein the locking section comprises a rounded and/or flattened locking edge. A locking edge of this type produces a defined contact point between the catch element and the locking section in the switched position of the indicating switch, i.e. when the catch element is locked by the locking section.  
           [0026]    In accordance with the invention, the trigger finger can abut a pretensioned intermediate part and have a projection in the contacting area which engages with play behind a recess in the intermediate part. This permits pre-mounting and pre-tensioning of the intermediate part on the trigger finger without having it rotate out of the mounted position in response to pre-tensioning. This considerably simplifies installation of the canceling device.  
           [0027]    A further similar development provides that the locking section is connected to a mushroom-like shoulder which engages with play in a corresponding recess in the casing. This mushroom-like shoulder facilitates assembly in that the locking section can be pre-mounted on the casing such that it cannot drop out during assembly of the other parts.  
           [0028]    Finally, it is particularly advantageous when the trigger finger comprises a control body having a substantially square overall contour. Such an actuation section permits a maximum path of motion for the loaded part, in particular of a deflecting element with which the control body cooperates. 
       
    
    
       [0029]    Two embodiments of the invention are described in detail below with reference to the accompanying drawing.  
       BRIEF DESCRIPTION OF THE DRAWING  
       [0030]    [0030]FIG. 1 shows a plan view of a first embodiment of a canceling device, in its neutral central position;  
         [0031]    [0031]FIG. 2 shows a plan view of the canceling device of FIG. 1 in one of its switched positions;  
         [0032]    [0032]FIG. 3 shows a plan view of the canceling device of FIG. 1 during automatic canceling from the switched position into the neutral central position;  
         [0033]    [0033]FIG. 4 shows a perspective view of the trigger finger and an intermediate part of the canceling device of FIG. 1;  
         [0034]    [0034]FIG. 5 shows a perspective view of a casing part with a catch profile, and two locking sections of the canceling device of FIG. 1;  
         [0035]    [0035]FIG. 6 shows a perspective view of some components of the canceling device of FIG. 1, in the assembled state;  
         [0036]    [0036]FIG. 7 shows a perspective view of a switching piece of the canceling device of FIG. 1;  
         [0037]    [0037]FIG. 8 shows a perspective view from below of several casing parts of the canceling device of FIG. 1;  
         [0038]    [0038]FIG. 9 shows a schematic sketch of a second embodiment of a canceling device, in its neutral central position;  
         [0039]    [0039]FIG. 10 shows the canceling device of FIG. 9 during automatic canceling from a switched position into the neutral central position; and  
         [0040]    [0040]FIG. 11 shows a detailed plan view of the canceling device of FIG. 9.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0041]    The overall canceling device for a blinker switch in an motor vehicle is designated with the reference numeral  10  in FIG. 1. It comprises a casing part  12  with a catch profile insert  14 , a trigger finger  16 , two deflecting elements  18  and  20 , two locking doors  22  and  24  and one switching piece  26  of which only the rollers  28  and  30 , the catch elements, a triangular locking part  32 , and a point of rotation  34  are shown for reasons of clarity. The switching piece  26  is only symbolically indicated by dash-dotted lines interconnecting the rollers  28  and  30 , the triangular locking part  32 , and the point of rotation  34 . A blinker switch, also only indicated with dash-dotted lines, has been designated by reference numeral  36 .  
         [0042]    The casing part  12  comprises a bottom  38  (transparent in FIG. 1) and a wall  40  extending perpendicular thereto. FIG. 8 shows the bottom in detail. A collar-like support  42  is also formed on the wall  40  and disposed coaxially with respect to an axis of a steering shaft (only shown with dash-dotted lines: see, in particular, FIGS. 6 and 8).  
         [0043]    The catch profile insert  14  is inserted into the casing part  12  within the wall  40 . Its exact design is shown in FIG. 5. The locking doors  22  and  24  are disposed in a recess of the catch profile insert  14  and pivot about axes  45   a  and  45   b  via lower pivot pins (not shown in the drawing) in corresponding recesses of the catch profile insert  14 . The visible upper pivot pins  47   a  and  47   b  engage in corresponding recesses (without reference numerals) in the bottom  38 . Each locking door  22  or  24  bears, on each lever arm  49   a  or  49   b , a control pin  51   a  or  51   b  which cooperates with the deflecting element  18  or  20  in a fashion which will be explained below. To secure the locking doors  22 , 24  from falling out during mounting, a mushroom-like shoulder  43   a ,  43   b  is formed on their lower side which engages with some play behind a corresponding longitudinal recess  41   a ,  41   b  in the catch profile insert  14  (see FIG. 6).  
         [0044]    In the position of the locking doors  22  and  24  shown in FIGS. 1 and 5, two upper catch depressions  46  and  48  or two lower catch depressions  50  and  52  are formed in the catch profile insert  14 . The locking doors  22  and  24  bear a locking section  54  or  56 , parallel to their respective pivot axis, which separates corresponding catch depressions  46  and  48  or  50  and  52  from each other. The catch profile insert furthermore comprises two canceling sections  53   a  and  53   b , each with one step  55   a ,  55   b.    
         [0045]    As seen on the left-hand side of FIG. 1, the casing part  12  has an opening  58  through which the blinker lever  36  passes. While the switching piece  26  and the corresponding catch elements are indicated only symbolically by a dash-dotted line in FIGS. 1 through 3, the exact design of the switching piece  26  can be extracted from FIG. 7. This figure also shows the catch elements  62  and  64  which are guided in the switching piece  26 . In the neutral central position shown in FIG. 1, the catch elements  62  and  64  extend downwardly from the center into the catch depression  52  or vertically upwards into the catch depression  46 . The radially inner sections of the two catch elements  62  and  64  are hollow and accommodate a helical pressure spring (not shown) by means of which the two rollers  28  and  30  of the catch elements  62  and  64  are loaded against the catch profile insert  14  or the locking doors  22  and  24 .  
         [0046]    The trigger finger  16 , shown in particular detail in FIG. 4, has a carrier  66  oriented towards the axis  44  of the steering shaft when installed, which is disposed in a retracted state in the central position of the canceling device  10  (FIG. 1). The carrier  66  is formed on a control body  68  which has a substantially longitudinal shape when viewed from the top. Supporting wings  70  are formed on the sides of the control body  68 . The side of the control body  68  facing away from the carrier  66  is provided with a guiding pin  72  on its upper side and with a stop pin  74  on its lower side. The guiding pin  72  engages in a guiding slot  73  in the bottom  38  of the casing  12 .  
         [0047]    The end of the control body  68  facing away from the carrier  66  is rounded and abuts an end face of a cylindrical intermediate part  76 . The end of the intermediate part  76  facing away from the trigger finger  16  is open. A helical pressure spring  78  is disposed in the intermediate part  76  and is supported, on one side, on the end of the intermediate part  76  facing the trigger finger  16  and, on the other side, on a supporting element  80  which is fixed to the housing and which is only symbolically shown in the figures. The end face of the intermediate part  76  facing the trigger finger  16  is provided with a recess  82  which engages with play behind a hook-shaped pin  84  formed on the control body  68  which has an insertion slope permitting pre-mounting of the intermediate part  76  on the trigger finger  16  to facilitate installation of the canceling device  10 .  
         [0048]    The two deflecting elements  18  and  20  each have the shape of a flat elbow lever, each with one first lever section  98  and  100  and a second lever section  99  and  101 . A pivot axis  90  and  92  is defined by a pin  86  and  88 . The pivot pins  86  and  88  are accommodated in corresponding recesses  94  and  96  in the bottom  38  of the casing part  12  (see FIG. 8).  
         [0049]    Each end of the second lever section  99  and  101  of the deflecting element  18  and  20  facing the respective locking door  22  and  24  has a slot  102  and  104 , which has two sections, disposed at an angle with respect to each other. The longitudinal axis of that region of the slot  102  and  104 , which accommodates the control pin of the locking door  22  and  24  in the neutral central position of the canceling device,  10  (shown in FIGS. 1 and 2) is perpendicular to a radius line intersecting the axis of rotation  90  and  92  of the deflecting element  102  and  104  and that region. FIG. 1 shows the corresponding reference numerals for the upper deflecting element  18  only. The corresponding region of the slot  102  is designated with reference numeral  106 , its longitudinal axis is referenced with  108 , and the radius line with  110 . The other region of the respective slot  102  and  104  is formed such that its longitudinal axis is disposed at an angle with respect to the direction of motion of the respective locking section  54  and  56 .  
         [0050]    The longitudinal axis of the corresponding region of the upper slot  102  has the reference numeral  112 . The control pins  51   a  and  51   b  of the locking doors  22  and  24  are slidingly accommodated in the slots  102  and  104 . One guiding pin  114  and  116  is formed on the first lever section  98  and  100  proximate the trigger finger  16  and is disposed on a side thereof facing away from the trigger finger  16  to engage with play in corresponding guiding slots  117   a ,  117   b  in the bottom  38  of the casing part  12 .  
         [0051]    A helical pressure spring  118  is tensioned between the first lever section  98  or  100  of the deflecting element  18  or  20  and the upper or lower wall  40  of the casing part  12  which is shown in detail only in the upper region of FIG. 1 and is otherwise indicated by a dash-dotted line. One end of the helical pressure spring  118  surrounds a projection  120  formed on the lever  98 . The other end is received in a sleeve  122  whose closed end is rounded. This closed end is received in a depression  124  in the wall  40  of the casing part  12 .  
         [0052]    The helical pressure spring  118  loads the lever section  98  or  100  towards the trigger finger  16 . The guiding slots  117   a  and  117   b  are dimensioned and disposed to form a stop, thereby leaving a gap between control body  68  of the trigger finger  16  and the deflecting levers  18  or  20  in the position shown in FIGS. 1 and 2.  
         [0053]    The function of the canceling device  10  is now explained, in particular, with reference to FIGS. 1 through 3.  
         [0054]    In the neutral central position shown in FIG. 1, the guiding pins  114  or  116  of the deflecting elements  18  or  20  abut the inner ends of the guiding slots  117   a  or  117   b . The second lever sections  99  or  101  of the deflecting elements  18  and  20  are therefore located in a position proximate to the wall  40  of the casing part  12 . The control pins  51   a  or  51   b  on the projections  49   a  or  49   b  of the locking doors  22  and  24  are located in the locking regions  106  of the two slots  102  and  104 . In this position, the two locking doors  22  and  24  are kinematically locked and inwardly pivoted such that the two locking sections  54  and  56  of the locking doors  22  and  24  form an elevated section within the profile contour of the catch profile insert  14 .  
         [0055]    The two rollers  28  and  30  of the catch elements  62  and  64  lie in the catch inserts  48  or  52  formed in this fashion, thereby locking the blinker lever  36  in the horizontal position shown in FIG. 1. The triangular locking part  32 , which is a component of the switching piece  26 , is disposed in a central position approximately on the central axis of the opening  58 .  
         [0056]    The stop pin  74  of the trigger finger  16  abuts the tip of the triangular locking part  32 . In this position, the trigger finger  16  is loaded by the helical pressure spring  78  and the intermediate part  76  which abuts the trigger finger  16 . The triangular locking part  32  thereby prevents a rightward motion of the trigger finger  16  (in FIG. 1), i.e. towards the steering shaft  44  in response to the direction of loading of the helical pressure spring  78 .  
         [0057]    When the user presses the blinker lever  36  downwards, the switching piece  26  is also pivoted about the point of rotation  34 . The roller  28  of the catch element  62  is thereby moved, via the rising locking door  22 , in opposition to the force of the helical pressure spring (not shown) disposed between the two catch elements  62  and  64 . When the roller  28  of the catch element  62  has overcome the locking section  54  of the locking door  22 , it is pressed, in response to the force of the helical pressure spring, into the catch depression  46  which is delimited on its right-hand side by the locking section  54 . This position of the switching part  26  is shown in FIG. 2.  
         [0058]    The rotary motion of the switching piece  26  also moves the triangular locking part  32  upwards such that the stop pin  74  of the trigger finger  16  is released from the tip of the triangular locking part  32 , and slides along its side surface thereby releasing the trigger finger  16  for motion, in response to the direction of loading of the helical pressure spring  78 , in the direction of the arrow  126 . This release motion terminates when the guiding pin  72 , provided on the trigger finger  16 , abuts the right end of the guiding slot  73  in the bottom  38  of the casing part  12  (see FIG. 2). In the position of FIG. 2, the carrier  66  of the trigger finger  16  clearly projects towards the steering shaft  44 .  
         [0059]    Turning of a steering wheel (not shown in the drawing) produces corresponding turning of the steering shaft  44 . A cam  128  is connected to the steering shaft. In response to the rotary motion, the cam  128  pushes the carrier  66  of the trigger finger  16  in the direction of the arrow  130  (see FIG. 3) thereby pivoting the trigger finger  16  about an axis which extends parallel to the axis of the steering shaft  44 , as defined by the guiding pin  72 . Due to this pivoting motion of the trigger finger  16 , the control body  68  presses against the first lever section  98  of the deflecting element  18  thereby pivoting same about the axis of rotation  90  given by the pivot pin  86  and in the direction of the arrow  132 , in opposition to the direction of loading of the helical pressure spring  118 .  
         [0060]    This pivoting motion also produces pivoting of the second lever section  99  of the deflecting element  18  in the direction of the arrow  134 . This causes the control pin  51   a  on the projection  49   a  of the locking door  22  to slide out of the locking region  106  of the slot  102  and move towards the upper end of the slot  102  (in FIG. 3). The maximum pivoting angle of the deflecting element  18  is delimited by the guiding slot  117   a  in the bottom  38  of the casing part  12  and by the length of the slot  102 .  
         [0061]    The sliding motion of the control pin  51   a  of the locking door  22  in the slot  102  pivots the locking door  22  about the pivot axis  45   a  until it comes to rest in a substantially horizontal position shown in FIG. 3. In this position, the locking section  54  of the locking door  22  is completely retracted such that the two catch depressions  46  and  48  are no longer present. The roller  28  of the catch element  62  is no longer locked by the locking section  54 .  
         [0062]    The lower roller  30  of the lower catch element  64  of FIG. 3 is pressed by the helical pressure spring at an inclined angle against the wall of the catch profile insert  14 , thereby pivoting the switching piece  26  in the direction of the arrow  138  and back into its original position shown in FIG. 1. The stop pin  74  of the trigger finger  16  is thereby pressed to the left by the side surface of the triangular locking part  32  in opposition to the direction of loading of the helical pressure spring  78  such that the carrier  66  of the trigger finger  16  once more assumes its retracted position.  
         [0063]    As soon as the cam  128  releases the carrier  66  of the trigger finger  16 , same pivots about the axis given by the guiding pin  72  into its neutral central position (shown in FIG. 1) in response to loading by the helical pressure spring  118  as transferred via the first lever section  98  of the deflecting element  18 . The first lever section  98  of the deflecting element  18  and, at the same time, the second lever section  99  provided with the slot  102  perform a corresponding pivoting motion thereby returning the locking door  22  together with the locking section  54  into the position shown in FIG. 1 in which catch depressions  46  and  48  are to the left and right of the locking section  54 .  
         [0064]    A second embodiment of a canceling device  10  will be explained with reference to FIGS.  9 - 11 . The parts having functions equivalent to the first embodiment have the same reference numerals and may not be described in detail.  
         [0065]    The two purely schematic representations of FIGS. 9 and 10 show a stepped slot  102  (not a bent one) in the deflecting element  18 . A linearly displaceable catch element  22  is provided (instead of a pivotable locking door) and is connected to a control pin which is slidingly accommodated in the stepped slot  102 . As shown in FIG. 10, the deflecting element  18  is displaced towards the left in response to loading by the carrier  66  of the trigger finger  16  thereby causing the guiding pin of the catch element  22  to slide in the slot  102  from a locking stage  106  into an opening stage  140 . Consequently, the catch element  22  moves in the direction of the arrow  136  thereby releasing the roller  28  of the catch element  62  which permits movement of the roller  28  in the direction of the arrow  138  and return of the blinker lever  36  into its neutral central position shown in FIG. 11.