US 4,290,682 A · Electromagnetically operated shutter

Abstract

In the slit shutter disclosed, an actuator transmits the rotational force of an electromagnetic drive arrangement to move shutter blades through opening and closing cycles. A spring arrangement for engaging the actuating means serves to aid the shutter movement at the beginning of the cycle and retard the shutter movement at the end of each cycle while the spring arrangement is energized during its retarding action. According to an embodiment of the invention, the spring arrangement encounters an arm of the actuator at the end of each cycle, absorbs the arm movement during the retardation, and uses the energization to aid the movement at the start of the next cycle. The spring arrangement again encounters the arm at the end of the next cycle.

Claims4

Dependent claims

An electromagnetically operated type slit exposure shutter comprising:

(a) electromagnetic drive sources each having a permanent magnet and a movable magnetic coil for receiving current to exert a rotative force;
(b) shutter blades arranged to open and close an exposure aperture;
(c) shutter blade actuating means for transmitting the rotative force of said electromagnetic drive sources to said shutter blades so as to make said shutter blades run down or up to effect an exposure and a resetting;
and
(d) spring means for engaging said shutter blade actuating means, said spring means being arranged for imparting to said actuating means a driving force aiding the running of said shutter blades when said shutter blades start to run, and for imparting a braking force to said actuating means when said shutter blades near the end of movement thereof, while being energized by said actuating means.

2 more elements

Dependencies are inferred from the claim text.

Electromagnetically operated shutter

Life of this patent

Electromagnetically operated shutter

Life of this patent

Abstract

Claims4