Device for opening and closing shutter blade without bounce

Abstract

The device for opening/closing the shutter blade(s) of a photographic camera comprises an electromagnetic actuator coupled with the shutter blade(s) and adapted to open or close the same upon supply of a current from an electrode source through a driver and/or a control circuit to the actuator in one direction or in the opposite direction. The electric source is a constant current circuit and a current regulating circuit is interposed between the constant current circuit and the driver thereby permitting the shutter opening speed to be adjusted by regulating the current regulating circuit. Alternatively, the electric source is a constant voltage circuit and a resistor is connected in series between the driver and the actuator thereby permitting the shutter opening speed to be adjusted by regulating the resistance of the resistor. The control circuit may be so constructed that the shutter opening current is interrupted a predetermined time prior to the fully opened position of the shutter blade(s) and the shutter closing current is supplied for a predetermined time period after interruption thereof to avoid the bounce of the shutter blade(s). One of a pair of symetrically shaped and actuated shutter blades is stopped by stopper means at the fully opened position so as to be bounced therefrom and the bouncing movement is cancelled by the inertia of the opening movement of the other shutter blades at the fully opened position by virtue of the coupling of the pair of shutter blades commonly with the actuator.