EP2028673B1 - Electric switch - Google Patents

Abstract

The electrical switch has a housing (1). A plastic deformation element (6) is provided on the actuator (3) for damping the excessive force effect in addition to the elastic deformation element (7). The deformation energy consumption of the deformation element is greater than the deformation energy consumption of the elastic deformation element. The elastic deformation element is impinged on the actuator during excessive force effect and impinges the plastic deformation element of the actuator.

Description

The invention relates to an electrical switch according to the preamble of claim 1.

A switch according to the preamble of claim 1 is in DE-A-2837461 described.

There are a variety of embodiments of electrical switches in particular in the form of buttons and keyboards known. The switch according to the invention is based on a housing in which an actuator in the form of a print head is linearly inwardly movable. In the depressed state of the actuator closes or - in so-called normal-closed-buttons - this opens an electrical switch contact.

A problem with such switches is the so-called vandalism, so the protection of the switch in case of violence. Here, the market demands ever greater demands on the degree of protection against impacts.

For this reason, it is known to provide the above-described electrical switch with an elastic damping element, which is intended to dampen excessive force on the actuator. Although these elastic damping elements can compensate for an excessive amount of force, the force effect in daily practice can be so great that the deformation energy of the elastic damping element is not sufficient to absorb the forces. It then comes due to the initiated energy to irreversible deformations and destruction with the result of functional failures.

The invention is therefore based on the object , the electrical switch of the type specified in such a way that the so-called vandalism is further improved.

The technical solution is characterized by the features in the characterizing part of claim 1.

The basic idea of the electrical switch according to the invention lies in a 2-stage actuator damping. In this way, a higher vandal protection is achieved by using elastic and plastic deformation energies. The damping of the actuator forces thus takes place in two stages. In the first stage by the elastic damping element takes place - with respect to the damping element - non-destructive low energy absorption. In the second stage due to the plastic damping element is a high energy absorption. Because this element is plastic, this high energy absorption due to deformation is irreversible. Thus, a high vandal protection can be achieved with this system. Should an overload take place, the plastically deformed damping element can be replaced with a corresponding structural design of the electrical switch, without having to replace the entire switch.

The development according to claim 2 proposes that from the time from which the plastic damping element is acted upon by the actuator, the elastic damping element continues to be applied as well. As a result, an additive energy intake is achieved.

According to the embodiment in claim 3, it is in the elastic damping element is preferably a rubber or plastic. Other materials which have elastic damping properties are equally conceivable.

The plastic damping element according to the embodiment in claim 4 is preferably metal, for example copper. Other metals are basically also conceivable.

A preferred embodiment proposes according to claim 5, that it is in both the elastic damping element and in the plastic damping element in each case to O-rings. These have the advantage that they are low in the trade, so that the switch according to the invention can be realized inexpensively.

A further preferred embodiment proposes according to claim 6, that the O-rings are arranged concentrically with respect to the central axis of the actuator. This creates a compact design. The underside of the mushroom-shaped actuator rests on the force applied to the O-rings.

A preferred development thereof proposes according to claim 7, that the O-ring of the elastic damping element has a larger cross-sectional diameter than the O-ring of the plastic damping element. The "cross-sectional diameter" is not the outer diameter of the O-ring to understand, but the diameter of the ring as such in a section perpendicular to the circular center line of the ring. This means that when the actuator is pushed further down, first the underside of the head of the actuator strikes the upper generatrix of the elastic damping element. After then the actuator has performed a certain stroke, then hits the bottom of the actuator on the upper generatrix of the plastic damping element.

Finally, the development proposes according to claim 8, that the O-rings rest on a platform of the housing. The case forms a sort of pot, on the bottom of the two O-rings lie.

Fig. 1

eine Seitenansicht des Schalters, teilweise geschnitten;

Fig. 2a bis c

verschiedene Stellungen des Betätigers beim Nachuntendrükken.

An embodiment of an electrical switch according to the invention will be described below with reference to the drawings. In these shows:

Fig. 1

a side view of the switch, partially cut;

Fig. 2a to c

different positions of the actuator when Nachuntendrükken.

The probe has a housing 1, which is cup-shaped in the upper region with a central axis substantially perpendicular to the platform 2.

In the housing 1, an actuator 3 is linearly displaceable mounted. This is mushroom-shaped with an axial guide rod 4 and with an actuating plate 5 at the upper end of the guide rod 4 is formed.

Concentric about the central axis of the switch inside a plastic deformation element 6 in the form of an O-ring of a metal, in particular copper is arranged. In the outer region of the platform 2, an elastic damping element 7 is likewise mounted in the form of an O-ring, but here made of rubber or plastic.

• Fig. 1 sowie Fig. 2a zeigen die Grundstellung. Die Betätigungsplatte 5 des Betätigers 3 liegt dabei auf dem O-Ring des elastischen Deformationselements 7 auf. Da der Querschnittsdurchmesser des O-Rings des plastischen Deformationselements 6 geringer ist als der entsprechende Durchmesser des elastischen Deformationselements 7 besteht hier noch ein Abstand.

The operation is as follows:

• Fig. 1 such as Fig. 2a show the basic position. The actuating plate 5 of the actuator 3 rests on the O-ring of the elastic deformation element 7. Since the cross-sectional diameter of the O-ring of the plastic deformation element 6 is less than the corresponding diameter of the elastic deformation element 7 is still a distance.

When pushing down the actuator 3 ( Fig. 2b ), the elastic deformation element 7 is elastically compressed, associated with a low energy absorption by the elastic reversible deformation. Fig. 2b shows the situation in which the actuator plate 5 is just before touching the O-ring of the plastic deformation element 6.

If the force on the actuator 3 becomes even greater (FIG. 3), then the O-ring of the plastic deformation element 6 is also deformed, namely plastically deformed, connected to a high energy absorption. When the force ceases, the elastic deformation element 7, because of its reversibility, moves the actuator 3 back to its original position, but due to the irreversible plasticity of the plastic deformation element 6, this O-ring remains in its deformed shape.

However, after this 'vandal attack' on the electrical switch, the O-ring of the plastic deformation element 6 can be exchanged so that the vandalism protection is restored.

LIST OF REFERENCE NUMBERS

1

casing

2

platform

3

actuator

4

guide rod

5

operating plate

6

plastic deformation element

7

elastic deformation element

Claims (8)

1. Electric switch with a housing (1), with an actuator (3) which can be moved linearly in the housing (1) and which, in the pressed state, closes or opens an electric switching contact, and with an elastic deformation element (7) arranged between the housing (1) and the actuator (3) to damp an excessive action of force on the actuator (3), characterised in that in addition to the elastic deformation element (7), a plastic deformation element (6) is also provided to damp the excessive action of force on the actuator (3), the absorption of deformation energy of the plastic deformation element (6) being greater than the absorption of deformation energy of the elastic deformation element (7) and, upon an excessive action of force on the actuator (3), firstly the elastic deformation element (7) can be acted upon by the actuator (3) and then the plastic deformation element (6).
2. Switch according to the preceding claim, characterised in that on actuation of the plastic deformation element (6), the elastic deformation element (7) can also be acted upon by the actuator (3).
3. Switch according to any one of the preceding claims, characterised in that the elastic deformation element (7) consists of rubber or plastics material.
4. Switch according to any one of the preceding claims, characterised in that the plastic deformation element (6) consists of metal.
5. Switch according to any one of the preceding claims, characterised in that the elastic deformation element (7) and the plastic deformation element (6) are O-rings.
6. Switch according to claim 5, characterised in that the O-rings are arranged concentrically with respect to the centre axis of the actuator (3).
7. Switch according to claim 5 or 6, characterised in that the O-ring of the elastic deformation element (7) has a larger cross-sectional diameter than the O-ring of the plastic deformation element (6).
8. Switch according to any one of claims 5 to 7, characterised in that the O-rings rest on a platform (2) of the housing (1).

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