THERMOSENSITIVE ACTUATOR AND AUTOMATIC FIRE EXTINGUISHER

PROBLEM TO BE SOLVED: To provide an inexpensive automatic fire extinguisher that has a simple structure, can be reduced in size, and can be set up easily in a general home etc., and to provide a thermosensitive actuator used for the fire extinguisher. SOLUTION: The fire extinguisher 11 is composed of an extinguishant container 12 made of a synthetic resin that can be broken by an external impact, a supporting plate 13 which holds the container 12, and the thermosensitive actuator 21 integrally provided on the plate 13. The actuator 21 is provided with a knocking member 24 urged by a spring in a displaceable state from a standby position to an operating position, a locking member 31 which locks the member 24 to the standby position and can be displaced to release the member 24, and a wire 51 the length of which is contracted when the ambient temperature changes and which is made of a shape memory alloy. The wire 51 is stretched around the member 31 in a state where its both ends are fixed and its central part is engaged with the member 31 so as to control the displacement of the member 31. When the wire 51 contracts and the locking member 31 is displaced due to the heat of a fire, the knocking member 24 moves to the operating position in a moment due to the urging force of the spring and collides with the container 12. Consequently, the container 12 is broken and the extinguishant contained in the container 12 is scattered and extinguishes the fire. COPYRIGHT: (C)2004,JPO&NCIPI