GB1363750A - Electric switch - Google Patents

Abstract

1363750 Inertia switch DYNAMIT NOBEL AG 22 Nov 1971 [30 Nov 1970] 54212/71 Heading H1N An electric switch, Fig. 1, actuated in response to acceleration of the switch, comprises a conductive casing 3 having fixed contact surfaces 10, 11 and movable contact members 6 biased into contact with surfaces 10, 11 by spring 7 and mounted on a conductive pin 1 the pin being fixed in a non-conducting bush 2, the free end of the pin locating in an insulating bush 4 of a hollow axially adjustable threaded conductive member 5. The adjustable member is screwed inwardly to set a predetermining compressive force in the spring and then soldered around its junction with the conductive part 13. A insulated bush 14 insulates the member 13 from the case. The electrical circuit is established from lead 19 through the member 5 and the associated member 6, through the spring 7 to the other contact member 6 and via the casing 3 to the other lead 20. Any forces, in line with the direction of the pin 1, of sufficient magnitude to overcome the bias of the spring cause the contacts to be broken. The contact members may have different masses and the compression adjustment screw may be dispensed with (Fig. 5, not shown). The casing may be filled with a gas or liquid such as silicone oil or glycerine in order to provide desired different clamping properties. Such fluid is introduced via the aperture 17 and sealed with the screw 16. In Fig. 7 the solid contact members are replaced by hollow members 6d which engage contact faces 23 on tubes 22a, the surface 24 of the tube being insulated to prevent accidental contact during operation. Insulation on the inner surface of the case may also be provided or the case may be of insulated construction. As before a solder layer 28 seals the switch after the adjusting screw 22 is preset. Switches responsive to several directions of acceleration may be formed in a single ease or by a combination of several switches.