| 摘要 |
A damper for a flapdoor that does not provide any damping effect when its movable shaft (3) is rotated with the door in one sense, but effectively damps the rotary movement of the flapdoor when the movable shaft (3) is rotated with the door in the other sense. A coil spring 7 forms both a power source and a one-way clutch for engaging or disengaging the shaft (3) with a movable member (4) depending on the sense of rotation of the movable shaft to cause a viscous shearing drag in the viscous fluid (c) contained in the damper. A damper for a flapdoor having such an arrangement can have a simplified configuration as compared with a damper provided with a separate coil spring as power source and a separate one-way clutch and therefore can be realized with reduced dimensions. Moreover, since much a one-way clutch can be prepared from a coil spring (7) without requiring any additional processes and by simply engaging a portion of the coil spring with the movable member (4), the rest of the coil springfunctioning as power source, and the damper can be realized at a significantly reduced cost. |
