Inertial igniters with safety pin for initiation with low setback acceleration

Abstract

Inertial igniters for initiating a thermal battery and methods of preventing initiation of an inertial igniter are provided. The method including: biasing a mass element from a base element with a spring element connecting the mass element and the spring element; and removably disposing a safety member between the mass element and the base element to prevent relative movement between the mass element and base element to prevent accidental initiation of the inertial igniter. The method can further comprise removing the safety member prior to subjecting the inertial igniter to all-fire conditions.

1 . An inertial igniter comprising:
 a mass element;   a base element;   a spring element connecting the mass element and the base element; and   a safety member removably disposed between the mass element and the base element for preventing relative movement between mass element and base element to prevent accidental initiation of the inertial igniter.   
     
     
         2 . The inertial igniter of  claim 1 , wherein the mass element comprises one of a two part pyrotechnic and the base element comprises the other of the two part pyrotechnic. 
     
     
         3 . The inertial igniter of  claim 2 , further comprising a thermal battery connected to the base element, the base element having at least one opening for passing fire and/or sparks resulting from contact between the two part pyrotechnics to the thermal battery. 
     
     
         4 . The inertial igniter of  claim 1 , wherein a gap is formed between the mass element and the base element and the safety member is disposed in the gap. 
     
     
         5 . The inertial igniter of  claim 4 , wherein the gap is at least partially annular and the safety member comprises a semicircular member disposed in the annular gap. 
     
     
         6 . The inertial igniter of  claim 5 , wherein the spring element, base element and mass element are circular and the spring member has a diameter smaller than the mass element and base element. 
     
     
         7 . The inertial igniter of  claim 5 , wherein the semicircular member has first and second ends forming a partial arc having a radius such that it provides a positive lock when disposed between the mass element and the base element. 
     
     
         8 . The inertial igniter of  claim 1 , wherein the safety member further comprises a tab having a hole for insertion of a wire. 
     
     
         9 . The inertial igniter of  claim 1 , wherein the spring element is a bellows. 
     
     
         10 . The inertial igniter of  claim 9 , wherein the bellows is sealed to both the mass element and base element to form a sealed enclosure between the mass element and spring element. 
     
     
         11 . The inertial igniter of  claim 1 , wherein one or more of the base element and mass element are disc-shaped. 
     
     
         12 . A method of preventing initiation of an inertial igniter, the method comprising:
 biasing a mass element from a base element with a spring element connecting the mass element and the spring element; and   removably disposing a safety member between the mass element and the base element to prevent relative movement between the mass element and base element to prevent accidental initiation of the inertial igniter.   
     
     
         13 . The method of  claim 12 , further comprising removing the safety member prior to subjecting the inertial igniter to all-fire conditions.