JPS6486121A - Electromagnetically driven shutter - Google Patents

Abstract

PURPOSE:To speed up the closure of the shutter and to preclude its bound by opening the shutter by feeding electricity to an electromagnetic actuator and closing the shutter by stopping feeding the electricity, and providing buffer members which determine a 1st position of a permanent magnet closing the shutter closely to a 2nd position where the shutter is closed. CONSTITUTION:The electromagnetically driven shutter is opened by the displacement of the permanent magnet 23 from the 1st position A1 to the 2nd position A2 by feeding the electricity to an electromagnet 37, and when the electromagnet 37 is powered off after the shutter is opened fully or while the shutter is in the opening operation, the permanent magnet 23 is displaced from the 2nd position A2 to the 1st position A1 with attractive force to the end part of the core 39 of the electromagnet 37 to close the shutter. The bound of this permanent magnet 23 is absorbed by the buffer members 29 and 30 at the 1st position 1 of the permanent magnet 23 where the shutter is closed. In this case, the 1st position A1 is set a little bit closer to the 2nd position A2 than a position A0 where the permanent magnet 23 generates the largest attractive force to the end part of the core 39, so the bounding of the electromagnetic actuator is minimized. Consequently, the closing operation of the shutter is speeded up and its bound is precluded.