Gas damped deceleration switch

Abstract

A deceleration switch for detecting deceleration in excess of a certain magnitude which, for instance, may be indicative of a vehicle crash, comprising: a pair of electrodes having internal and external ends; a contact set electrically connected to the internal ends; a mass supported by a spring or the like and adapted to move from a neutral position to an active position for actuating the contact set under its inertia force when deceleration of a certain magnitude is applied to the switch; and a circuit for checking the electric conductance between the internal end and the external end of at least one of the electrodes. The circuit may consist of either lead wires connected to the internal and external ends of the electrodes or a resistor connected across the internal ends of the electrodes. In the latter case, by conducting electric current through the resistor from the external ends of the electrodes and monitoring the flow of the electric current, it is possible to detect any break in the electric path of the deceleration switch. Thus, since the condition of the electrodes, which typically consist of elastic materials and are subjected to vehicle vibrations, can be always monitored, the reliability of the deceleration switch is much improved.