WO2003043040A2

WO2003043040A2 - Electromechanical impulse generator comprising a rotatable cam wheel in the form of a toothed ring

Info

Publication number: WO2003043040A2
Application number: PCT/DE2002/004191
Authority: WO
Inventors: Roland Ruegenberg
Original assignee: Methode Electronics Inc.
Priority date: 2001-11-12
Filing date: 2002-11-12
Publication date: 2003-05-22
Also published as: WO2003043040A3; EP1444712A2

Abstract

The invention relates to a cam wheel (2) comprising circularly distributed toothed cams (9). Said cam wheel can be rotated over a pivotable trip cam (8) which slightly protrudes between the toothed cams. Said trip cam (8) is connected to laterally projecting contact arms (12) in a fixed manner, the free ends of said arms being at a distance over mating contacts (14) of a printed circuit board, in a central position. During the rotation of the cam wheel (2), the trip cam (8) is driven in the same direction and is pivoted until the contact arm (12) oriented in the rotational direction is positioned on the associated mating contact in such a way that it makes contact. When the rotation continues, the trip cam (8) goes back into its central starting position, under the action of a restoring spring (11, 26), the contact being broken. Said arrangement enables the structure of the impulse generator to be simplified and the functional reliability thereof to be increased.

Description

description

Electromechanical pulse generator with a sprocket-like rotatable cam wheel

The invention relates to an electromechanical pulse generator with a sprocket-like rotatable cam wheel and a pivoting switching cam of a pivoting part engaging in it for alternative actuation of two switching contacts depending on the direction of rotation, the switching cam assuming a central position in an initial position and by toothed cams of the cam wheel can be deflected in opposite directions depending on its direction of rotation and thereby actuates movable contact arms of the switching contacts.

Such a pulse generator is e.g. made known by EP 0229306 A2. The switch cam is part of a rocker arm pivotally mounted in a housing. In their middle position, the switch cam resiliently engages between the teeth of the cam wheel, the two switch contacts remaining unactuated. When the cam wheel is rotated in one direction, the switching cam is carried along by the adjacent toothed cam with radial displacement and swung out laterally in this direction. A side projection of the rocker switch is pressed against one of the movable arms and the switch contact is actuated on this side. When the cam wheel is turned in the other direction, the switch cam is pivoted out in the opposite direction and a projection opposite the mirror image

The rocker switch is pressed against the other arm and the other switch contact is actuated. After the two cam tips have slid past each other, the rocker switch snaps back into its central position, whereby the switch contact in question is reset to its initial state. When the cam wheel is incrementally rotated further, a sequence of directional counting pulses is generated in this way, which can be converted into electrical control pulses, for example. Furthermore, US4395604A and US3975601A have disclosed rotary pulse generators with cam wheels and switching cams engaging in them, in which a sliding contact moves in a pulsating manner via one or a second stationary contact depending on the direction of rotation. Because of the associated frictional wear, such pulse generators are not suitable for frequent and fine-step operations with a high clock frequency. The device also becomes stiff due to the frictional resistance. In particular, the sluggish return process becomes so slow that the pulse separation is not ensured, since with undefined rapid manual rotation the sliding contact no longer resets in time when the next tooth of the cam wheel already comes into engagement.

The invention has for its object to reduce the construction costs for the pulse generator provided with mounting contacts and to increase its functional reliability.

This object is achieved by the invention according to claim 1. The switching mechanism of the pulse generator is considerably simplified by combining the swivel part and the movable contact arms. The contact arms and the switching cam have a defined positional relationship to one another which is determined before assembly. Installation tolerances are irrelevant. Instead of three separate functional parts according to the prior art, according to the invention only one part needs to be assembled with correspondingly little effort. The space required is so small that the pulse generator e.g. instead of a rocker switch in a control block of an automobile or e.g. can be used in the cramped cross section of a steering wheel spoke. The one-piece contact part further reduces the manufacturing outlay and simplifies the electrical connection. The resilient mounting contacts have the particular advantage of quick resetting, which enables reliable pulse separation.

Advantageous further developments of the invention result from the features characterized in claims 2 to 20. The support spring according to claim 2 serves as a simple return member, which can be produced according to claim 3 in one go with the contact part.

The arrangement of the parts according to claims 4 and 5 has simple geometrical positions in the essential axes and functional surfaces, which enable low manufacturing costs and high functional reliability. In particular, the kinematics of the functional parts can be optimized with just a few setting parameters in terms of contact, wear and operation.

The deflection according to claim 6 results in a simple manner the switching cam, which is connected directly to the contact arms.

Similarly, the bend according to claim 7 forms the tilt axis for the spring part. Thus, the majority of all essential functions of the pulse generator are assigned to the spring part, which can be manufactured as a one-piece component with little effort.

The crosspieces according to claim 8 form the support springs and the contact piece and at the same time define bending axes about which the support springs and the contact arms can be bent in the opposite direction, as a result of which the spring strokes can be increased.

Through the development according to claim 9, the spring part is double symmetrical, so that no tilting moments occur about its longitudinal axis and the bearing, contact and support forces are evenly distributed.

The double contact according to claim 10 increases the contact security to the counter contacts.

The swivel part with the switching cam and the tilt axis according to claim 11 can be with the spring part, for example, by overmolding the same be firmly connected. The plastic used can have good sliding properties and be particularly abrasion-resistant.

The circuit board according to claim 12 contains all mating contacts in precise assignment and simple wiring.

The attachment of support parts according to claim 13 for the cam wheel and the swivel part directly on the circuit board directly ensures the height assignment between the counter-contacts and the swivel part with the contact arms or between the swivel part and the cam wheel.

The development according to claim 14 results in a particularly compact, slim functional unit, the installation dimensions of which can be adapted to those of other switches or display elements. The contact surfaces for the support spring and the mating contacts for the contact arms can be formed on contact elements which protrude vertically through a housing base and at the same time serve on the underside of the base as connecting elements or plug elements for the external wiring, so that a printed circuit board is not required.

Due to the development according to claim 15, the pulse generator can serve, for example, as a scroll wheel for operating a screen connected to an on-board computer.

The drive wheel according to claims 16 and 17 or 18 serves e.g. the generation of an additional signal similar to a mouse click. Since the swivel part is mounted on a fixed tilting axis, the switch cam penetrates so deeply between the toothed cams that it can no longer swing out laterally from this recess and thus blocks the cam wheel with the drive wheel when pressed in against unintentional turning.

The storage in a swing arm according to claim 19 allows easy assembly with precise guidance. The latching element according to claim 20 prevents unwanted rotation of the cam wheel and thus pivoting of the spring part and an undefined impulse.

Embodiments of the invention are shown in the drawing and are explained in more detail below. Show it:

FIG. 1 schematically shows a perspective view of a pulse generator with part of an instrument board,

2 shows a side view of the pulse generator according to FIG. 1 with a rocker arm and an additional contact in a central position, FIG. 3 shows a side view of the pulse generator according to FIG. 1 in another functional position.

Figure 4 is a perspective view of a pulse generator in a modified form Figure 5 is a perspective view of another pulse generator.

According to FIGS. 1 and 2, a manually operable drive wheel 1 is firmly connected to a cam wheel 2 and rotatable about an axis of rotation 3 which extends parallel to the plane of a printed circuit board 4. The drive wheel 1 partially protrudes from a cover 5 of an instrument panel and can thus be turned or pressed in manually. Between the circuit board 4 and the axis of rotation 3 there is the tilt axis 6, parallel to this, of a swivel part 7, which is provided with a switching cam 8 projecting towards the axis of rotation 3. This protrudes with play between toothed cams 9 of the gear-like cam wheel 2.

The swivel part 7 is rigidly connected to a spring part 10 which extends essentially parallel to the printed circuit board 4 at the height between the tilt axis 6 and the switching cam 8 and protrudes from the swivel part 7 on both sides. Its free ends are bent towards the circuit board. It is through two middle longitudinal cuts into the support spring 11 and two that extend into the vicinity of the swivel part Contact arms 12 divided. The bridge-like support spring 11 is supported with its rounded free ends under prestress on potential-carrying contact surfaces 13 of the printed circuit board 4. The free ends of the contact arms 12 are spaced above flat counter contacts 14 of the printed circuit board 4.

The axis of rotation 3 of the drive wheel 1 is mounted in a rocker arm 15 which extends in the longitudinal direction of the spring part 10 and which is pivotally fixed at one end to a support bearing 16 of the circuit board. On the diametrically opposite side of the drive wheel 1, the other end of the rocker 15 rests on an additional contact 17 in the form of an elastomeric contact dome. By radial finger pressure on the drive wheel 1, the rocker 15, as indicated by dash-dotted lines, is pivoted so far toward the printed circuit board 4 that the contact dome compresses in a contacting manner and triggers an additional electrical pulse.

According to Figure 3, the drive wheel 1 with the cam wheel 2 is rotated so far that a flank of a toothed cam 9 on the switching cam

8 rests and deflects it laterally. The pivot part 7 is pivoted so far that the contact arm 12 pointing in the direction of rotation is pressed in a contact-making manner against the surface of its counter-contact 14. When the cam wheel 2 continues to rotate, the tip of the toothed cam 9 slides over the cam

Switch cam 8 away and releases it. As a result, the restoring force of the support spring 11 is effective and the switching cam 8 pivots back with the pivot part 7 and the contact arms 12 into its central position, in which the contact with the counter-contact 14 is interrupted again. When turning in the opposite direction, the other contact can be closed and disconnected in the same way.

In the case of a modified pulse generator according to FIG. 4, the same reference numerals have been used for parts of the same function and similar shape as in FIGS. 1 to 3. The rocker arm 15 is mounted in another support bearing 23 of a housing base 24 and carries the drive wheel 1 with the cam wheel 2 whose axis of rotation 3 appears in a dash-dotted line interpreted side wall of the rocker 3 is guided. The modified spring part 25 is arranged between the housing base 24 and the cam wheel 9 and consists of a contact part 18 and two support springs 11 arranged on its two sides, which are integrally connected to the contact arms 12 via narrow cross bars 21 in the central region thereof.

Below the axis of rotation 3, the contact part 18 has a bead-like bend directed towards the axis of rotation, which forms the switching cam 19 for actuating the contact part 18. Below the switching cam 19, the support springs 11 are provided with bead-like bends 20 pointing away from the axis of rotation, which serves as a tilting axis 20 and is supported in a groove-like recess in a bearing part 22 attached to the housing base 24.

A further pulse generator according to FIG. 5 differs from the pulse generator according to FIG. 4 essentially by a modified spring part 33, the middle section of which is arranged on the side facing away from a housing base 34. The free ends of the support springs 26 and the contact arms 36 of the contact part 27 are bent approximately at right angles to the central portion around the cam wheel 9. Contact elements 37 protruding from the housing base 34 in the direction of the axis of rotation 3 have the contact surfaces 31 and mating contacts 30 for the free ends of the contact part 27 and the support springs 26 and are designed on the outside of the housing base 34 as plug contacts 35.

The switch cam 19 bent out toward the cam wheel and the

Tilt axis 20 are arranged in the middle section of the spring part 33. The tilting axis 20, which is designed as a bead-like deflection, is supported on the side facing away from the cam wheel 9 in a recess of a bearing part 24, indicated by dash-dotted lines, which is formed on a housing part of the pulse generator (not shown).

On the side of the cam wheel 9 facing away from the switching cam 9 there is on the housing base 34 between the ends of the spring part 33 another additional contact 29 is provided, whose block-like housing serves as a support for the contact elements 37. The additional contact 29 is actuated by a radially resiliently deflectable locking element 32 which is in contact with the cam wheel 9 and which prevents the cam wheel 9 from being rotated unintentionally and thus prevents the spring part 33 from pivoting and an undefined impulse, and secures the rest position of the switching cam 19 guided in vertical slots, not shown, of the housing. The drive wheel 1 can accordingly be moved toward the housing base 34 and actuate the additional contact 29, which is also connected to one of the plug contacts 35.

reference numeral

1 drive wheel

2 cam wheel

3 axis of rotation

4 circuit board

5 cover

6, 20 tilt axis

7 swivel part

8, 19 switching cams

9 tooth cams

10 spring part

11, 26 support spring

12, 36 contact arm

13, 31 contact surface

14, 30 counter contact

15 rocker arms 6, 23 support bearings

17 additional contact 8, 27 contact part

21 cross piece 2, 24 bearing part 5, 33 spring part 8, 34 housing base

29 Additional contact

32 locking element

35 plug contact

37 contact element

Claims

claims

1. Electromechanical pulse generator with a ring gear-like rotatable cam wheel (2) and a swiveling switching cam (8, 19) engaging in it for alternative actuation of two contact contacts depending on the direction of rotation, the switching cam (8, 19) in a starting position assumes a central position and can be deflected in opposite directions by toothed cams (9) of the cam wheel (2) depending on the direction of rotation thereof and thereby actuates movable contact arms (12, 36) of the switching contacts, characterized in that the two movable contact arms (12, 36) are integrated in one piece into a common two-armed, pivotably mounted resilient contact part (18, 27) and are fixedly connected to the switch cam (8, 19) and transmit its deflection movement directly to the switch contacts.

2. Pulse generator according to claim 2, so that the switching cam (8, 19) is firmly connected to at least one support spring (11, 26) which extends essentially parallel to the contact part (18, 27).

3. Pulse generator according to claim 2, characterized in that the contact part (18, 27) and the support spring (11, 26) are integrally connected to a spring part (10, 25, 32) and that the support spring (11, 27) to the electrical Switching potential is applied.

4. Pulse generator according to one of claims 1 to 3, characterized in that the toothed cams (9) of the cam wheel (2) are designed to protrude radially and that the switching cams (8, 19) about one of the axis of rotation (3) of the cam wheel (2 ) parallel tilt axis (6, 20) can be pivoted, from which it projects towards the axis of rotation (3).

5. Pulse generator according to claim 4, characterized in that the spring part (10) extends in the region of the switching cam perpendicular to the plane of the two axes (3, 6) and that bending axes of the contact arms parallel to the axis of rotation (3) of the cam wheel (2) extend.

6. Pulse generator according to one of claims 1 to 5, that the switching cam (19) is formed by a cam-like deflection of the contact part (18, 27) pointing towards the cam wheel (2).

7. Pulse generator according to one of the preceding claims, that the tilting axis (20) is formed by a bead-like deflection of the support spring (11, 26) pointing away from the cam wheel and is supported in a groove-like depression of a stationary bearing part (22, 24).

8. Pulse generator according to claim 7, characterized in that the support spring (11, 26) and the contact arms (12, 36) of the contact part (18, 27) are connected to one another via narrow crosspieces (21) which are connected between the switching cam (19). and the free ends of the contact arms (18, 36) are arranged.

9. Pulse generator according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that one of the support springs (11, 26) is provided on both sides of the contact part (18, 27).

10. Pulse generator according to one of the preceding claims, that the free ends of the contact arms (12, 36) are provided with a longitudinal slot to form a double contact.

11. Pulse generator according to one of the preceding claims, characterized in that the Switching cams (9) and the tilt axis (6) are formed on a swivel part (7) which is anchored on the contact part (18).

12. Pulse generator according to one of the preceding claims, characterized in that the bridge-like support spring (11) rests with its free ends on stationary contact surfaces (13) of a printed circuit board (4), which also has mating contacts (14) for the free ends of the contact arms ( 12) is provided.

13. Pulse generator according to claim 12, so that the circuit board (4) serves as a support base for the cam wheel (2) and the pivoting part (7) or the bearing part 21.

14. Pulse generator according to one of the preceding claims, characterized in that the free ends of the support spring (26) and the contact arms (36) are bent approximately at right angles to a central portion of the spring part (33), and that the contact surfaces (31) and mating contacts ( 30) extend parallel to the free ends.

15. Pulse generator according to one of the preceding claims, that the cam wheel (2) is fixedly connected to a manually operable coaxial drive wheel (1) which is provided with an actuating surface structured in the circumferential direction.

16. Pulse generator according to claim 15, so that the drive wheel (1) with its axis of rotation (3) for actuating at least one additional contact (17, 29) is displaceable towards the switching cam (8).

17. Pulse generator according to claim 16, characterized in that the switching cam (8) in its central position has a displacement distance corresponding to the axis of rotation (3) to the cam wheel (2).

18. Pulse generator according to claim 16, so that the switching cam (8) can be resiliently deflected relative to the tilt axis (6, 20) by a stroke corresponding to the displacement path of the axis of rotation (3).

19. Pulse generator according to claim 15, 16 or 17, characterized in that the axis of rotation (3) of the drive wheel (1) with the cam wheel (2) is mounted in a rocker arm (15) which is at one end on a support bearing (16, 23rd ) pivotally supported and which rests with its diametrically opposite end on a movable part of the additional contact (17).

20. Pulse generator according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that on the periphery of the cam wheel (2) is provided between the toothed cams (9) engaging locking element (32) which secures the rest position of the switching cam (19).