| 摘要 |
PURPOSE:To preclude the possibility of retarded stating or disabled starting by providing a damping torque generating section enabling to apply a damping torque to a rotary member including a shutter at its driven state. CONSTITUTION:A motor shaft 1b incorporated with a motor shaft 1a is extended to other side from a motor 1 and a friction cylinder 3 is provided to the end of the motor shaft 1b. A structure that the damping torque generating section is provided with a rotary dash pot corresponding to a prescribed part of a rotary member may be adopted. Thus, while the motor 1 is driven, a friction torque of a contact face between the friction cylinder 3 and a friction disk 4 acts like a damping torque to the motor shafts 1a, 1b at all times. As a result, the fluctuation of speed of a shutter disk 2 during its driving and the vibrating state caused just before its halt are suppressed, resulting that the time from the start to the stop is remarkably reduced more than the time of a conventional mechanism. Thus, even if the next start command is given closely timewise, the possibility of the retarded start or disabled start of the shutter disk 2 is precluded.
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