| 摘要 |
PROBLEM TO BE SOLVED: To provide a plunger for cameras which functions as a movable iron core which is easily attracted in the initial stage in a solenoid used for the cameras. SOLUTION: The plunger is constituted by arranging the movable iron core (rear part 5a1, front part 5a2) which is composed of an approximately cylindrical, movable magnetic material and a fixed magnetic material (fixed iron core 5c) in a cavity in a solenoid 5 on which a coil 5d is wound. The movable iron core is attracted to the fixed iron core by the magnetic force which is generated by applying voltage to the coil 5d. Furthermore, a predetermined elastic body (spring) 5e is disposed in the gap between the front and rear parts of the movable iron core. In this plunger for cameras, a predetermined gap is maintained between the rear part 5a1 and the front part 5a1 by the spring 5e of the movable iron core when voltage is not applied. When voltage is applied, the gap which has been maintained is narrowed, and the movable iron core is attracted to the fixed iron core 5c side more powerfully and by a stroke shorter than that in the conventional camera plungers.
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