| 摘要 |
Reflex photographic apparatus incorporating an reflecting member which is moved during a photographic cycle to convert an optical path from viewing-focusing to exposure configurations. A low-rate torsion drive spring moves the reflecting member from a viewing position to an exposure position quickly, while minimizing elastic rebound at the termination of movement. A motor is used to return the reflecting member to its viewing position following a photographic exposure. Mounted coaxially with, and disposed within the drive spring, is a second low-rate torsion spring which is operative to provide a lost-motion connection between the reflecting member and the return motor. Should the reflecting member be restrained during its return movement, the lost-motion connection permits the motor to complete its cycle without overloading.
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