EP0786787A2 - Self-adjusting tappet-switch - Google Patents

Abstract

The invention relates to a self-adjusting plunger switch, with a housing (3) for receiving at least one contact (7, 19) to be actuated, with an actuating element (5, 27) slidably guided in the housing for actuating the at least one contact (7, 19), which is held in a rest position pushed out of the housing by a resilient element (11) and which comprises a slide (5) guided in the housing and a plunger (27) connected to it in an adjustable manner in the actuating direction, the plunger (27) comprising first locking means ( 45), which can be brought into engagement with second locking means (29a) of the slide from a angular position (adjustment position) which enables the adjustment between tappet (27) and slide (5) by rotating the slide (27) about its longitudinal axis are (locking position), whereby locking the position between the plunger (27) and slide (5) is noticeable. <IMAGE>

Description

The invention relates to a self-adjusting plunger switch with the features of the preamble of claim 1.

Self-adjusting plunger switches are already known in the prior art in many different embodiments. They are used, for example, in vehicles as brake light switches. Switches designed in this way serve the purpose of tolerances when installing the switch or changes in the actuation path of the actuating part, e.g. of the brake pedal. For this purpose, self-adjusting plunger switches have an actuating element, which is displaceably guided in the housing of the switch, for actuating at least one contact, which consists of a slide which is guided in the housing and a plunger which is connected to it in the actuating direction so as to be adjustable. The plunger is usually connected to the slide in a snap-in manner, so that the desired switching point of the switch can be achieved by adjusting the plunger in the slide.

The self-adjusting switch is first installed in the vehicle in the desired position, the plunger being locked in the most protruding position from the slide. After the switch has been installed, the actuating part, for example the brake pedal, is then moved vigorously in the actuating direction, as a result of which the slide is first moved into its end position and then the plunger with its latching area is pressed correspondingly far into the slide. This compensates for tolerances when installing the switch or in the actuation path of the brake pedal. Furthermore, this results in the advantage that damage to the switch in the event of a change in the actuation travel, for example the pedal travel, is reliably avoided with a sufficiently large latching area between the plunger and slide.

DE 35 27 874 A1 describes a self-adjusting plunger switch with a hollow cylindrical shaft part which can be inserted into a bore in a plate. At one end, the shaft part has at least one inwardly projecting latching lug on its inner surface, which engages in a thread of a shaft. The shaft is part of the switching device and has a switch button on one side and a switch housing on the other side, in which the contact elements are located. To adjust the switching device, the switch button is actuated by an actuating element, e.g. a brake pedal, the shaft being pushed back into the shaft part until the switch button has the desired distance with respect to the actuating element.

From DE 29 21 439 A1 a plunger switch is known which can be used in particular as a brake light switch, the plunger switch being pushed through a sleeve which serves to fasten the switch in an assembly opening until the plunger touches the brake pedal and the end face of the shaft lies against the pedal. The switch is then rotated through a limited angle with respect to the sleeve, engaging ribs and grooves of the switch with corresponding ribs and grooves of the sleeve. In this way, the switch is fixed axially with respect to the sleeve.

However, the known self-adjusting plunger switches have the disadvantage that, under certain circumstances, an undesired adjustment of the desired latching position between the plunger and slide can occur, in particular the thermal expansion of switch components or wear of the latching areas. Fiddling in the area of the switch can also lead to an unintentional adjustment of the desired locking position (after self-adjustment). This results in a shift of the switching point, so that, for example, the brake light only starts from a certain position of the brake pedal is switched on, in which a considerable braking effect has already been achieved. Before this switching point, the vehicle following this vehicle receives no indication of the braking process that has already started.

The present invention is therefore based on the object of providing a self-adjusting plunger switch in which, after the self-adjustment of the plunger has been self-adjusted, the relative position between the plunger and slide is securely fixed.

The invention solves this problem with the features of claim 1.

The provision of first locking means on the plunger, which are in an angular position (adjustment position) enabling the adjustment between the plunger and slide, disengages from the second locking means provided on the slide, ensures simple self-adjustment in the self-adjusting plunger switch according to the invention.

After self-adjustment has taken place, however, the first locking means provided on the tappet can be brought into engagement with the second locking means provided on the slide by rotation through a predetermined angular amount, as a result of which the position between the tappet and slide can be locked. In this locking position, the plunger can no longer be adjusted relative to the slide, so that an unintentional adjustment of this position is reliably ruled out.

In addition, this locking possibility has the advantage that a renewed adjustment process can be carried out by a renewed rotation of the plunger into the adjustment position. This is necessary, for example, if the braking device has been readjusted and thus the pedal travel has been changed.

In the preferred embodiment of the invention, the plunger engages in a known manner in an axial recess of the slide, the first locking means being provided on the region of the plunger engaging the slide and the second locking means on the corresponding partial region of the slide.

Of course, however, it is also conceivable that, in the reverse manner, the plunger has an axial recess in which an extension of the slide engages accordingly. The first and second locking means are then to be provided accordingly.

In the preferred embodiment of the switch according to the invention, the first and second locking means have at least one catch and a counter-catch cooperating therewith, which form a locking mechanism.

The second locking means can comprise a resilient arm which engages in the recesses of the detent forming the first locking means. This results in a particularly simple and inexpensive construction and simple assembly of the individual switch elements.

At least the steepness of the flanks of the recesses, which point in the direction of actuation, of the at least one catch must be selected so that the catch and the resilient arm act as a barrier at least in the actuation direction of the plunger. In this way, an adjustment of the plunger relative to the slide in the actuating direction is excluded in the locking position. In contrast, the plunger can be pulled out of the slide against the direction of actuation by applying a sufficient tensile force. In this way, in the cases in which the actuating part for the plunger / slide system has moved further away from the outer end of the plunger in its starting position, the plunger can also be readjusted in its locking position.

Preferably, however, both flanks of the at least one rest are selected in their steepness so that the rest and the resilient arm act in both directions as a ratchet.

In the preferred embodiment of the invention, the radius of the plunger in the region of the at least one catch of the first locking means is selected such that the plunger or catch and the inner wall of the axial recess of the slide limit the radial movement of the at least one resilient arm in the locked position such that a locking effect occurs in the direction of the longitudinal axis of the plunger. In other words, even if the steepness of the flanks of the detent is chosen so that a latching displacement between the plunger and slide would be possible together with the resilient arm, a locking effect is achieved by limiting the radial movement of the resilient arm in the locking position .

Furthermore, in the preferred embodiment of the switch according to the invention, the radius of the plunger in the region of the at least one long side of the plunger, which cooperates with the at least one resilient arm in the adjustment position of the plunger, is selected such that the plunger and the inner wall of the axial recess of the slide ensure radial movement of the at least one resilient arm so far that an adjustment of the plunger relative to the slide is made possible.

In this way, on the at least one longitudinal side of the plunger, which cooperates in the adjustment position with the at least one resilient arm, an adjustment catch can be provided which, in conjunction with the at least one resilient arm, enables a latching adjustment between the plunger and slide.

In the preferred embodiment of the invention, the plunger has a substantially circular cross section with at least one flattened portion, the flattened longitudinal side in the adjustment position with the at least one resilient arm cooperates. In this case, the recess of the slide in which the plunger engages can also have a circular cross section, for example, the diameter of which essentially corresponds to the maximum diameter of the plunger. In this way it is ensured that the resilient arm in the locking position is practically completely received by a recess of the catch forming the first locking means or is at least limited in its radial direction of movement in such a way that locking of the plunger is ensured.

In the preferred embodiment of the invention, the spring is designed as a U-spring and the plunger has an essentially circular-cylindrical shape with flattened sides lying opposite one another. In this case, the adjustment position is when the plunger is in the angular position in which the flattened longitudinal sides lie essentially parallel to the two spring arms. In this position, the two spring arms can be bent out so far in the radial direction that a latching adjustment of the plunger relative to the slide is possible.

By rotating the plunger through 90 °, the two resilient arms remain in the same circumferential recess, but due to the enlarged diameter in this position, they are moved so far in the radial direction outward that a further radial resilient movement of the arms is prevented. This leads to a secure locking of the plunger.

In the preferred embodiment of the invention, the at least one resilient arm is slightly angled in its front region such that this angled region engages behind the at least one flattened side of the plunger, so that the spring is prevented from falling out. This prevents the spring from jumping out during the rotational movement of the plunger and also prevents the plunger from getting caught with the slide.

In the preferred embodiment of the invention, the plunger has at least one longitudinal groove which interacts with at least one projection on the inner wall of the axial recess of the slide so that the rotary movement of the slide is locked in the locking position and / or the adjustment position. The at least one projection can be provided on a partial area of the wall of the slide which is designed as a resilient tongue.

In the preferred embodiment, the at least one projection can simultaneously serve as a stop for limiting the movement of the tappet relative to the slide in the direction of the tappet opposite to the actuating direction of the tappet and, for this purpose, cooperate with a stop surface provided on the tappet.

Further embodiments of the invention result from the subclaims.

Fig. 1

einen Längsschnitt durch eine Ausführungsform des Schalters nach der Erfindung;

Fig. 2a

eine teilweise aufgebrochene Seitenansicht des Schiebers mit darin montiertem Stößel gemäß Fig. 1;

Fig. 2b

einen Längsschnitt durch Fig. 2a in einer Ebene senkrecht zur Zeichenebene;

Fig. 2c

einen Querschnitt entlang der Linie I-I in Fig. 2b;

Fig. 2d

eine Darstellung gemäß Fig. 2c bei 90 ° gedrehtem Stößel;

Fig. 3a

eine Seitenansicht des Stößels;

Fig. 3b

eine Seitenansicht des um 90° um seine Längsachse gedrehten Stößels;

Fig. 3c

einen Schnitt durch den Stößel entlang der Linie I-I in Fig. 3a und

Fig. 3d

einen Schnitt durch den Stößel entlang der Linie II-II in Fig. 3b.

The invention is explained in more detail below with reference to an embodiment shown in the drawing. The drawing shows:

Fig. 1

a longitudinal section through an embodiment of the switch according to the invention;

Fig. 2a

a partially broken side view of the slide with the plunger mounted therein according to FIG. 1;

Fig. 2b

a longitudinal section through Figure 2a in a plane perpendicular to the plane of the drawing.

Fig. 2c

a cross section along the line II in Fig. 2b;

Fig. 2d

a representation of Figure 2c with 90 ° rotated plunger.

Fig. 3a

a side view of the plunger;

Fig. 3b

a side view of the plunger rotated by 90 ° about its longitudinal axis;

Fig. 3c

a section through the plunger along the line II in Fig. 3a and

Fig. 3d

a section through the plunger along the line II-II in Fig. 3b.

The embodiment shown in Fig. 1 of a self-locking plunger switch 1 according to the invention essentially consists of a housing 3, in which a slide 5 is guided to be longitudinally displaceable. Contacts 7 are arranged in the housing, the connection ends 7a of which are guided to the outside in a socket part 1a of the housing 3, so that these connection ends 7a can be contacted by means of a suitably designed plug (not shown).

The slide 5 has on its underside a recess 9 for receiving the end of a helical spring 11. The other end of the coil spring 11 is supported on the bottom 13 of the housing 3, so that the slide 5 is acted upon by the coil spring 11 so that it is held in its rest position, which is supported by the stop surfaces 15, 17 of the slide 5 and the Housing 3 is set. A movable contact 19 is provided on the slide 5 and is spring-mounted in a direction perpendicular to the longitudinal axis of the switch. This contact has two spherical sections 19a, each of which slides on the surface of one of the two fixed contacts 7. In the initial position of the slide 5, the contact between the two fixed contacts 7 and thus between the two connection ends 7a is therefore closed.

If the slide is subjected to a compressive force against the force of the helical spring 11, the slide is moved in this direction until it abuts the bottom 13 of the housing 3 with the two stop ends 21.

During this movement, the moving contact is lifted from the fixed contacts 7 from a certain position, since an elevation 23 is formed between the two fixed contacts. From this predetermined position of the slide 5, the contact between the two fixed contacts 7 and thus between the two connection ends 7a is therefore opened.

Of course, the contacts can also be designed in any other way. For example, the contacts can function as make contacts or multiple contacts can be provided.

In an axial, essentially circular-cylindrical recess 25 in the slide 5, a plunger 27 is arranged, which has a longitudinal region 27a, on which a catch is formed. The recesses and projections of the catch are preferably provided all around. By means of this catch and a spring cooperating therewith (FIG. 2), the plunger 27 can be locked in the recess 25 in the slide 5. This ensures the desired function of self-adjustability.

For the sake of completeness, it should be mentioned that a bellows 33 can be provided between a head 31 of the tappet 27 and the housing 3 as protection against contamination. This bellows 33 made of elastic material engages with beads provided on both ends in corresponding grooves on the head 31 of the tappet 27 or on the top of the housing 3.

The lockability of the plunger 27 in the slide 5 according to the invention is explained in more detail below with reference to FIGS. 2 and 3. The plunger 27 shown in Fig. 3 consists of a shaft 35 on which the above-mentioned longitudinal region 27a with a catch is formed and from the head 31 and a foot 37. The head 31 and the foot 37 each have a substantially circular cylindrical cross section.

The shaft 35 has flattened longitudinal sides 39 lying opposite one another in its longitudinal region 27a. The detent formed all around in this area, as will become clear later, therefore results in the first detent means or detent detents 45 on the flattened longitudinal sides 39, adjustment detents 41 and on the remaining partially circular-cylindrical outer surfaces 43 (FIGS. 2a and 2c).

In the remaining part 27b of the shaft 35, the tappet 27 has an approximately oval cross section, with longitudinal grooves 47 being formed in the narrow longitudinal sides.

As can be seen from FIG. 2 a, the part of the plunger 5 which is formed with a circular cylindrical wall and in which the recess 9 is provided for receiving the plunger 27 has an area 49 for receiving the spring 29. The spring 29 is designed as a U-spring and engages with angled arms 29a through corresponding openings in the cylindrical wall of the slide 5 in the recess 9. For better guidance of the arms 29a 9 guide grooves can be formed on the inner wall of the recess. Since a region 49 for receiving a spring 29 is preferably formed on opposite sides of the cylindrical wall of the slide 5, the cross section shown in FIGS. 2c and 2d results along the line I-I in FIG. 2b. The wedge-shaped webs 49a shown in FIGS. 2c and 2d serve for easier insertion of the ends of the spring arms 29a into the recesses 49b.

Although an area 49 for receiving a spring 29 is provided on opposite sides of the slide 5, of course only one is used to lock the plunger 27 Spring is required, but can be received by each of the areas 49.

The design of the spring 29 as an angled U-spring gives the advantage of simple assembly and simple mounting in the slide 5, whereby in addition by a correspondingly long design of the spring arms, i.e. the angled arms 29a and the associated arm parts running parallel to the longitudinal axis of the slide, the setting of practically any desired spring constant is possible.

The function of the switch according to the invention is thus as follows:

To install the switch, for example as a brake switch, the plunger is first inserted into the slide 5 with the spring 29 inserted, until the plunger 5 engages with the arms 29a of the spring 29 with the first recess of the adjustment catch 41. For this purpose, of course, the plunger 27 must be inserted into the recess 9 of the slide 5 such that the flattened longitudinal sides 39 of the longitudinal region 27a run parallel to the arms 29a. The complete with a system consisting of plunger 27 and slide 5 located in this adjustment position is then mounted in the desired position in the vehicle.

After installation is complete, the actuating part for the switch, for example the brake pedal, is actuated vigorously, so that the plunger is self-adjusted relative to the slide in the manner already described above.

After self-adjustment has been carried out, the plunger 27 is rotated manually by approximately 90 °, with latching lugs 51 (FIG. 2a) provided in the lower region of the recess 9 of the slide 5 latching into the longitudinal grooves on the narrow sides of the region 27e of the plunger 27. The cross section of the shaft 35 in the region 27b is designed such that for the rotary movement of the plunger and the locking with the locking lugs 51 the desired force curve is created. Of course, the spring force of the spring arms 29a and their interaction with the region 27a is also decisive for this. In this position, the plunger and slide are locked, since, according to FIG. 2c, the diameter of the plunger in the region of the partially circular cylindrical outer surface 43 or the locking catches 45 is selected such that the spring arms 29a on the inner wall of the recess 9 of the slide 5th or pressed into guide grooves provided therein.

The locking between the longitudinal grooves 47 and the locking lugs 51 is preferably designed so that a rotary movement of the plunger by 90 ° from the locking position into the adjustment position or vice versa is possible in any direction.

As can be seen from FIG. 2a, the latching lugs 51 also perform the function of a stop, since they engage the stop surfaces 37a of the foot 37 in the region of the broad sides of the region 27b of the shaft 35 in the adjustment position of the plunger 27, when it is pulled out of the recess 9 of the shaft 5 prevent.

Claims (16)

Self-adjusting plunger switch, a) with a housing (3) for receiving at least one contact (7, 19) to be actuated, b) with an actuating element (5, 27) slidably guided in the housing for actuating the at least one contact (7, 19), c) which is held by a resilient element (11) in a rest position pushed out of the housing and d) which comprises a slide (5) guided in the housing and a plunger (27) connected to it in an adjustable manner in the actuating direction,
characterized by e) that the plunger (27) has first locking means (45), which from an adjustment between the plunger (27) and the slide (5) enables an angular position (adjustment position) by a rotary movement of the plunger (27) about its longitudinal axis by a predetermined angular amount can be brought into engagement with second locking means (29a) of the slide (locking position), whereby a locking of the position between the plunger (27) and slide (5) can be achieved. Switch according to claim 1, characterized in that the plunger (27) with a partial area (27a) in an axial recess (25) of the slide engages and that the first locking means (45) are provided on this portion (27a) of the plunger (27) and the second locking means (29a) on the corresponding portion of the slide (3). Switch according to Claim 1 or 2, characterized in that the first (45) and second (29a) locking means are designed in the form of at least one catch and at least one counter-catch cooperating therewith, which form a locking mechanism. Switch according to claim 3, characterized in that the second locking means have at least one resilient arm (29a) which engages in the recesses of the at least one catch forming the first locking means (45). Switch according to claim 4, characterized in that the second locking means are designed as a U-spring (29), the arms (29a) of which cooperate with a catch (45) on opposite longitudinal sides of the plunger (5). Switch according to Claim 4 or 5, characterized in that at least the steepness of the flanks of the recesses of the at least one catch (45) pointing in the actuating direction is selected such that the catch and the at least one resilient arm (29a) at least in the actuating direction of the plunger (27) act as a ratchet. Switch according to one of Claims 4 to 6, characterized in that the radius of the plunger (27) in the region of the at least one catch (45) is selected such that the plunger (27) and the inner wall of the axial recess (25) of the slide (5 ) limit the radial movement of the at least one resilient arm (29a) in the locking position so that a locking effect occurs in the direction of the longitudinal axis of the plunger (5). Switch according to one of claims 4 to 7, characterized in that the radius of the plunger (27) in the region of the at least one longitudinal side (39) of the plunger (27), which in the adjustment position of the plunger with the at least one resilient arm (29a) cooperates, is selected so that the plunger (27) and inner wall of the axial recess (25) of the slide (5) allow the radial movement of the at least one resilient arm (29a) to such an extent that a displacement of the plunger (27) relative to the slide (5) is made possible. Switch according to one of Claims 4 to 8, characterized in that an adjustment catch (41) is provided on the at least one longitudinal side (39) of the plunger (27), which cooperates with the at least one resilient arm (29a) in the adjustment position, which, in conjunction with the at least one resilient arm (29a), enables a latching adjustment between the plunger (27) and slide (5). Switch according to one of claims 4 to 9, characterized in that the axial recess (25) has a substantially circular cylindrical cross section. Switch according to Claim 10, characterized in that the plunger (27) has an essentially circular cross-section with at least one flattened portion, the flattened longitudinal side (39) cooperating with the at least one resilient arm (29a) in the adjustment position. Switch according to claim 11, characterized in that the end of the at least one resilient arm (29a) is slightly angled. Switch according to one of the preceding claims, characterized in that the plunger (27) has first latching means (47) for fixing the adjustment position and / or the locking position which cooperate with second locking means (51) provided on the slide (5). Switch according to Claim 13, characterized in that the first latching means are designed as at least one longitudinal groove (47) which interacts with at least one projection (51) designed as a second latching means on the inner wall of the axial recess (25) or vice versa. Switch according to Claim 14, characterized in that the at least one projection (51) is provided on a partial region of the wall of the slide (5) which is designed as a resilient tongue. Switch according to claim 14 or 15, characterized in that the at least one projection (51) serves simultaneously as a stop for limiting the movement of the plunger (27) relative to the slide (5) in the direction opposite to the actuating direction of the plunger and for this purpose with an Plunger (27) provided stop surface (37a) cooperates.

Images