| 摘要 |
PURPOSE:To disengage a spur gear from a pinion when an overload is applied to a rotary mirror, and to prevent a breakdown, by allowing equal spring forces which are parallel to the spindles of a worm gear and the spur gear and opposite in direction, to operate upon both end surfaces of the spindles. CONSTITUTION:The rotational force of a motor 10 is transmitted to mirror 1 through a pinion 9, a spur gear 8, a worm gear 7, and a worm wheel 6 to rotate the mirror 1. Then, the mirror 1 is rotated to a down position and a limit switch contact 12 comes into contact with the limit switch contact of a stopper 3, stopping the operation of the motor 10. If the motor 10 does not stop rotating owing to a fault of the limit switch circuit, etc., the motor 10 is overloaded, but this overload is greater than a spring force F operating on the worm gear 7, which slides in an axial direction, so the spur gear 8 and pinion 9 are disengaged from each other, releasing the mirror 1 from being overloaded. |
