Electronic shutter device

Claim 1

A shutter mechanism for a focal plane camera comprising: a front screen and a rear screen, each of which is driven by a respective spring for film exposure; an electromagnet means for locking the rear screen in cocked position against the bias of its spring while energized; an electric circuit for controlling the time interval during which the electromagnet is energized; a first stopper member mechanically connected with the front screen to be moved therewith; a first locking element engageable with the first stopper member for preventing movement of the first stopper member to thereby lock the front screen in a cocked condition against the bias of its spring; a second stopper member mechanically connected with the rear screen to be moved therewith; an interlock means for interlocking the first and second stopper members during the shutter cocking operation and for locking the rear screen by the first locking member through the interlock means until the front screen is released; a second locking element having an armature mounted thereon, said second locking element being engageable with the second stopper member for preventing movement of the latter to thereby lock the rear screen in a cocked condition against the bias of its spring, said second stopper member comprising a rotatable cam provided with a circumferentially extending camming surface including a stopper portion, said second locking element including a segment disposed for continuously contacting said camming surface during rotation of the cam; and a biasing member connected to the second locking element for urging said segment into continual engagement with the camming surface and urging the armature into contact with the electromagnet means, said electromagnet means being disposed to cooperate with the biasing member for holding said segment against said stopper portion to thereby lock the rear screen through the second locking element while tHe electromagnet means is energized.