Pyrotechnic actuator mechanism, syringe and igniter assembly

Abstract

A pyrotechnic actuator mechanism comprises a cover member which includes a first wall member which is opposed to a release portion of an ignition unit, and a second wall member which is connected thereto and which has a free end portion embedded in a fixing member. When an ignition charge contained in the ignition unit is combusted, then the cover member is moved in the propulsion direction so that a predetermined closed space is expanded in the propulsion direction of a piston, and the movement of the cover member is regulated so that a state, in which the free end portion of the second wall member is embedded in the fixing member, is maintained at a maximum propulsion position of the cover member. Accordingly, the residue, which is produced by the combustion of the ignition charge, is preferably suppressed from being discharged or emitted to the outside.

1 . A pyrotechnic actuator mechanism comprising:
 a housing;
 an ignition unit disposed in the housing and including a release portion and an ignition charge, the release portion forming at least a portion of a space in the ignition unit to accommodate the ignition charge; 
 a fixing member fixing the ignition unit relative to the housing; 
 a cover member disposed in the housing and configured to move a first distance from a first position to a second position in response to combustion energy being released by the ignition charge and breaking through the release portion, the cover member comprising a first wall member and a second wall member, the first wall member covering the release portion, the second wall member having a first end connected to the first wall member and a second end spaced from the first wall member, wherein a portion of the second wall member is embedded a second distance measured from the second end into the fixing member when the cover member is in the first position, and wherein the second distance is greater than the first distance; and 
 a piston disposed in the housing relative to the ignition unit and configured to slide relative to the housing in response to the cover member contacting the piston when moving to the second position. 
   
     
     
         2 . The pyrotechnic actuator mechanism according to  claim 1 , wherein the portion of the second wall member has a columnar form. 
     
     
         3 . The pyrotechnic actuator mechanism according to  claim 1 , wherein the first wall member and the second wall member define a closed space. 
     
     
         4 . The pyrotechnic actuator mechanism according to  claim 3 , wherein the closed space includes a gas generating agent, wherein the ignition charge is configured to release a combustion product when ignited, and wherein the combustion product combusts the gas generating agent releasing the combustion energy. 
     
     
         5 . The pyrotechnic actuator mechanism according to  claim 1 , further comprising a piston rod, the piston rod extending from and being formed integral with the piston, wherein the housing comprises a protruding portion on a forward end side of the housing, the protruding portion protruding inwardly to define an opening through a central portion of the housing, and wherein at least a portion of the piston rod is disposed in the opening. 
     
     
         6 . The pyrotechnic actuator mechanism according to  claim 1 , wherein the piston includes a cylindrical skirt portion disposed at a lower end thereof and defining an accommodating space, at least a portion of the ignition unit being disposed in the accommodating space. 
     
     
         7 . An igniter assembly comprising:
 an ignition unit including a release portion and an ignition charge, the release portion forming at least a portion of a space in the ignition unit to accommodate the ignition charge;   an igniter collar accommodating the ignition unit;   a fixing member fixing the ignition unit relative to the igniter collar; and   a cover member configured to move a first distance from a first position to a second position in response to combustion energy being released by the ignition charge and breaking through the release portion, the cover member comprising a first wall member and a second wall member, the first wall member covering the release portion, the second wall member having a first end connected to the first wall member and a second end spaced from the first wall member, wherein a portion of the second wall member is embedded a second distance measured from the second end into the fixing member when the cover member is in the first position, and wherein the second distance is greater than the first distance.   
     
     
         8 . The igniter assembly according to  claim 7 , further comprising:
 a protrusion protruding inwardly to define an opening through a central portion of the igniter collar,   wherein the cover member moves the first distance when the cover member contacts the protrusion.   
     
     
         9 . The igniter assembly according to  claim 7 , further comprising:
 a columnar protruding portion protruding from the first wall member toward the opening, wherein an outer diameter of the columnar protruding portion is smaller than an inner diameter of the opening, such that the columnar protruding portion is fitted into the opening when the cover member moves the first distance.   
     
     
         10 . A method of manufacturing a pyrotechnic actuator mechanism, the method comprising:
 disposing an ignition unit in a housing, the ignition unit including a release portion and an ignition charge, the release portion forming at least a portion of a space in the ignition unit to accommodate the ignition charge;   fixing the ignition unit relative to the housing with a fixing member;   disposing a cover member in the housing such that the cover member moves, when in an assembled configuration, a first distance from a first position to a second position in response to combustion energy being released by the ignition charge and breaking through the release portion, the cover member comprising a first wall member and a second wall member, the first wall member covering the release portion, the second wall member having a first end connected to the first wall member and a second end spaced from the first wall member, wherein a portion of the second wall member is embedded a second distance measured from the second end into the fixing member when the cover member is in the first position, and wherein the second distance is greater than the first distance; and   disposing a piston in the housing relative to the ignition unit such that the piston slides, when in the assembled configuration, relative to the housing in response to the cover member contacting the piston when moving to the second position.   
     
     
         11 . The manufacturing method according to  claim 10 , further comprising maintaining hermetic sealing within the cover member until the cover member moves the first distance.