GB1204500A - Photographic cameras - Google Patents

Abstract

1,204,500. Photographic shutter mechanisms. EASTMAN KODAK CO. Oct.30, 1967 [Oct.31, 1966], No.49174/67. Heading G2A. A camera shutter has an open period depending on the force exerted on a shutter blade by an electromagnet, the current through which is dependant on the light falling on an exposure meter. As shown in Fig.1, depression of the shutter release 3 releases a plate 4 which moves under a spring bias 5. The shutter blade 2 is subjected to the increasing bias of a spring 10 as the plate 4 moves, but is held in the position covering the aperture 1 until the spring force exceeds the force exerted on the blade 2 by an electromagnet 6, when it is released and the aperture is uncovered until the projecting part of plate 4 covers it again. The current through the electromagnet 6 is dependant on a photo-resistor 8 in the circuit of the electromagnet, which circuit may also include a flashlamp 20, actuated by the movement of plate 4. In an alternative form, Figs. 5-7 (not shown), the shutter blade moves immediately on depression of the release 3 to uncover the aperture 1, but its motion is retarded as it abuts a pivoted lever, one end of which is attracted to the electromagnet 6.