PROBLEM TO BE SOLVED: To provide a technology for preferentially restricting discharge of residual generated through combustion of igniter powder.SOLUTION: This invention relates to a pyro-type actuator mechanism having an ignition part including igniter powder comprising a cover member defining a prescribed closing space covering a discharging location for combustion product and arranged to transmit combustion energy of the igniter powder to a piston and a fixing member for fixing ignition part before and after the combustion of the igniter powder. Then, the cover member has a first wall member opposing against the discharging location and a second wall member connected to the first wall member having its free end part buried in the fixing member. Upon combustion of the igniter powder, the cover member is moved in a propulsion direction in such a way that a prescribed closing space may be expanded in a propulsion direction of the piston and at the same time a motion of the cover member toward its propulsion direction is restricted in such a way that a buried state of the free end of the second wall member in the fixing member may be maintained at the maximum propulsion position.SELECTED DRAWING: Figure 1ACOPYRIGHT: (C)2016,JPO&INPIT
