DE10026352A1 - Electrical switching device - Google Patents

Abstract

An electrical switching device has an elastic switching mat (4) on a printed circuit board (1) with a hat-like switching area (5) which is lifted off the printed circuit board (1) and has an electrically conductive switching surface (7) on its inner end face (7). 5) against the conductor tracks (2, 3) of the circuit board (1) movable switching bridge (8). This switching bridge (8) is formed by a metal plate held by the inner end face (7).

Description

The invention relates to an electrical switching device device, which has an elastic on a circuit board Safety mat with at least one hat-like, from the Printed circuit board lifted off at its inner end face an electrically conductive, when pressure on the switching area against conductor tracks of the circuit board has a movable switching bridge.

Switching devices of the above type are for Controls of various types used and are well known and common. The switching bridge is usually done with a carbon coating generated, which is printed on the safety mat. Safety mats with switching bridges made of carbon have one Contact resistance on the order of 150-500 Ω, which is too high for some applications. If if you want to reduce this contact resistance, then you could think of using the carbon jumper with to use embedded metal particles, but this too undesirable fluctuations in the transition resistance  would lead. Instead of switching devices a usual touch with an elastic switch mat switch on with a metal jumper, then would the manufacturing cost for the switchgear increase significantly. Furthermore, the switching would change feeling significantly, which then especially not It is acceptable if there is more than one scarf on one control panel ter are provided, all have the same shift feeling should have, and which not for cost reasons all may be elaborately designed.

The invention is based on the problem of an electri cal switching device of the type mentioned above train that at the lowest possible cost precisely defined, low contact resistance results and compared to conventional switching devices with elas table shift mat no changed shift feeling testifies.

This problem is solved according to the invention in that the switching bridge through one of the inner face held metal plate is formed.

Such a switching device is comparable in cost can be produced inexpensively using conventional switching devices a switch mat and a printed switch bridge made of carbon. The switching device according to the invention has however a much lower contact resistance in on the order of <20 Ω. Furthermore, this is Contact resistance very evenly, so that at a series of switching devices always an exact same contact resistance results.

If the switching in the electrical switching device mat is made of rubber, you can according to a development tion of the invention provide that the switching bridge by  Vulcanizing is connected to the safety mat. Here this results in particularly low manufacturing costs.

If a control panel has different single pushbuttons and with the same feel different transition resistance stands are desired, you can according to another Further development of the invention provide that this individual pushbutton switch bridges off regarding their electri resistance of different materials sen.

The invention permits various embodiments. To further clarify their basic principle, there are two of which are shown in the drawing and are shown below described. They show in her

Fig. 1 shows a section through a switching device according to the invention with actuating part,

Fig. 2 shows a section through a second Schaltein direction.

Fig. 1 shows a circuit board 1 with two PCB tracks NEN 2, 3. On the circuit board 2 there is an elastic switching mat 4 , which has a hat-like switching region 5 leading away from the circuit board 1 . This has a stamp 6 directed towards the printed circuit board 1 with an end face 7 on which a metal plate is attached as a contact bridge 8 by vulcanization.

Above the switching mat 4 can be seen a push button 9 with a light box 10th If one presses this button 9 , the light box 10 comes against the switching area 5 and thereby presses the switching bridge 8 onto the two conductor tracks 2 , 3 , whereby these are electrically connected to one another.

FIG. 2 shows that the switching mat 4 side by side a plurality of individual push 11, 12 may have. The individual key switch 11 has a metal plate as a switching bridge 8 , while the individual key switch 12 has a carbon pressure 13 as a switching bridge, so that the latter has a higher contact resistance.

Claims (3)

1. Electrical switching device, which on an Lei terplatte an elastic switching mat with at least one hat-like, lifted off the circuit board Schaltbe rich, which has on its inner end face an electrically conductive, movable when pressed against the switching area against contacts of the conductor track, characterized in that that the switching bridge ( 8 ) is formed by a metal plate held by the inner end face ( 7 ). 2. Electrical switching device according to claim 1, wherein the switching mat consists of rubber, characterized in that the switching bridge ( 8 ) is connected by vulcanization to the switching mat ( 4 ). 3. Electrical switching device according to claims 1 or 2, characterized in that it comprises several individual key switches (11, 12) and these individual push aufwei sen (11, 12) switching bridges (8) with respect to their electrical resistance rule different materials.