Electromagnetically operated shutter

摘要

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.