PURPOSE: To reduce the charge torque of a shutter by charging part of the kinetic energy of shutter blades in a brake spring and discharging the elastic energy of the spring during shutter charging operation.
CONSTITUTION: A leading blade brake lever 12 and a trailing blade brake lever 17 are rotated with the forces of brake springs 21 and 24 respectively to enter motion paths of blade driving pins 10 and 11 and sand by there. In this state, releasing operation allows a leading and a trailing blade to start run successively, and the driving pins 10 and 11 strike the brake levers 12 and 17 at the ends of their run. At this time, part of the kinetic energy of the leading and trailing blades is charged as elastic energy in the brake springs 21 and 24. The charged elastic energy is discharged associatively with the shutter charging operation to apply charging-directional force to a shutter charging member, so the charging torque of the shutter is reduced.
SHIMADA FUMIO
YOSHIDA KATSUMI
CANON DENSHI KK