Electrical Setback Detection Switch

Abstract

A switch including: a first body having holes located at a longitudinal position; a movable second body having a concavity corresponding to the holes; a retaining ball positioned in the holes and corresponding concavity for restraining the second body from movement relative to the first body; an elastic element disposed on the body; a mass disposed on the elastic element, the mass moving the elastic element upon an acceleration event; and first and second electrical contacts positioned on the body such that when the acceleration event has a predetermined magnitude and duration, the mass moves past the longitudinal position to permit the retaining ball from releasing from the holes, thereby permitting the second body to move towards the first and second electrical contacts; wherein the second body includes a conductive portion for closing an electrical circuit between the first and second electrical contacts.

What is claimed is: 
     
         1 . A switch comprising:
 a first body, the first body having one or more holes located at a longitudinal position of the first body;   a second body movable relative to the first body, the second body having a concavity corresponding to each of the one or more holes;   a retaining ball positioned in each of the one or more holes and corresponding concavity for restraining the second body from movement relative to the first body;   an elastic element disposed on the body;   a mass disposed on the elastic element, the mass moving the elastic element upon an acceleration event acting on the first body; and   first and second electrical contacts positioned on the body such that when the acceleration event has a predetermined magnitude and duration, the mass moves past the longitudinal position to permit the retaining ball from releasing from the one or more holes, thereby permitting the second body to move towards the first and second electrical contacts;   wherein the second body includes a conductive portion for closing an electrical circuit between the first and second electrical contacts.   
     
     
         2 . The switch of  claim 1 , further comprising a casing for enclosing the body. 
     
     
         3 . The switch of  claim 1 , wherein the one or more holes comprises three holes. 
     
     
         4 . The switch of  claim 1 , wherein the elastic element is a helical spring. 
     
     
         5 . The switch of  claim 4 , wherein the mass is one of a solid portion of the helical spring or a more closely wound portion of the helical spring than other portions of the helical spring. 
     
     
         6 . The switch of  claim 1 , wherein the elastic element is a first elastic element and the switch further comprising a second elastic element for biasing the second body towards the first and second electrical contacts. 
     
     
         7 . The switch of  claim 1 , wherein the conductive portion has a shape for mating with a shape of the first and second electrical contacts.