| 摘要 |
PURPOSE:To raise the accuracy in case a screen-type focal plane shutter is operated, by controlling the front and rear screens by an electromagnetic device of the same type. CONSTITUTION:A front screen 13 and a rear screen 8 are wound up by pulleys 4, 5, and a drum 2, respectively. In a state that charging has been completed, hook levers 24, 25 for each screen are fitted into a hook hole and hold each screen. Adsorption pieces 28, 29 are adsorbed and held by release type electromagnets 31, 32 consisting of a permanent magnet and a de-energizing coil. The completion of charging is detected by photoelectric detecting devices 34, 35 opposed to a detecting part 13a of the front screen. When the release type electromagnet 31 is turned on by the release operation, the adsorption is released and the front screen travels. The traveling concerned is detected by the photoelectric detecting device, and it is made a countig start information of the exposure time. When the electromagnet 32 is turned on, the rear screen travels in the same way as the front screen. |
