Inertia switch device

An inertia switch device, comprising:

• (a) a housing having a conical seat;
• (b) an inertia mass located within the housing and movable from a rest position in response to acceleration or deceleration applied thereto, the inertia mass being formed by a spherical member located in the conical seat so as to be substantially independent of the direction of an applied acceleration or deceleration in a horizontal plane;
• (c) rigid operating means mounted within the housing and including a first arm disposed to be struck and moved by the inertia mass when the acceleration or deceleration has exceeded a threshold value, and a second arm having a bifurcated portion;
• (d) support means secured within the housing and having a bifurcated portion on which the bifurcated portion of said second arm is pivotally mounted for movement about a pivotal axis;
• (e) first, second and third electrical contacts mounted within the housing;
• (f) the first electrical contact being movable between first and second positions and disposed between and respectively engageable with the second and third electrical contacts, said first electrical contact having a bifurcated portion pivoted on said bifurcated portion of said support means;
• and
• (g) resilient biasing means connecting said second arm to said first electrical contact, and lying within the bifurcated portions so that a center-line of the resilient biasing means can move to either side of said pivotal axis to bias said first electrical contact stably to one of said positions dependent on the position of the operating means.