Patent ID: 8727646
Filing Date: 2014-05-20
Classification: G03B

Abstract:
1. A focal plane shutter for digital cameras in which a front blade and a rear blade are arranged in two blade rooms, respectively, the two blade rooms being formed by a middle plate partitioning a space between a shutter base plate and an auxiliary base plate, the focal plane shutter for digital cameras comprising: a front locking blade locking member into which a front blade driving member is locked until the front blade driving member is rotated by a biasing force of a front blade driving spring so as to start exposure operation of the front blade, a rear blade locking member into which a rear blade driving member is locked until the rear blade driving member is rotated by a biasing force of a rear blade driving spring so as to start exposure operation of the rear blade, a front blade lock releasing member which is made to come into contact with an iron-core member of a first electromagnet in a set state, is attracted and held by the iron-core member of the first electromagnet when a coil of the first electromagnet is electrified by a supply of electric current, and then, as the supply of electric current to the coil of the first electromagnet is cut off, is separated from the iron-core member of the first electromagnet by a biasing force of a front blade releasing spring to release the front blade driving member from the front blade locking member, a rear blade lock releasing member which is made to come into contact with an iron-core member of a second electromagnet in the set state, is attracted and held by the iron-core member of the second electromagnet when a coil of the second electromagnet is electrified by a supply of electric current, and then, as the supply of electric current to the coil of the second electromagnet is cut off, is separated from the iron-core member of the second electromagnet by a biasing force of a rear blade releasing spring to release the rear blade driving member from the rear blade locking member, a hold member which, in the set state, presses the front blade lock releasing member and the rear blade lock releasing member onto the iron-core member of the first electromagnet and the iron-core member of the second electromagnet, respectively, against the biasing force of the front blade releasing spring and the biasing force of the rear blade releasing spring, respectively, and, when the coil of the first electromagnet and the coil of the second electromagnet are electrified in shooting, relieves the front blade lock releasing member and the rear blade lock releasing member from a pressing force and is withdrawn from trajectories of the front blade lock releasing member and the rear blade lock releasing member, and a restraining member configured to rotate in a reciprocating manner in response to reciprocation of the hold member, wherein, in the set state, the restraining member has been moved into the trajectory of the rear blade lock releasing member, and then, when the hold member is withdrawn from the trajectories of the front blade lock releasing member and the rear blade lock releasing member and the coil of the second electromagnet is not electrified, the restrain member restrains the rear blade lock releasing member from moving away from the iron-core member of the second electromagnet before the rear blade lock releasing member releases the rear blade driving member from the rear blade locking member.