| 摘要 |
A safety handle releasably drives a shaft which is also otherwise powered. The shaft has an axis of rotation and a peripheral engagement band. The safety handle has a frame including a bearing aperture receiving shaft so as to be freely rotatable on and relative to the shaft, a lever arm extending away from the bearing aperture, and pivot means laterally spaced from the aperture. Centering means resiliently bi-directionally biases the drive handle and engagement means towards the centralized position. When the drive handle is grasped and twisted around the handle axis, the engagement means is pivoted to engage the engagement band, enabling torque exerted on the drive handle relative to the shaft axis to turn the shaft, but when the twisting effort is released, the centering means returns the handle and the engagement means to the centralized position, thereby releasing the engagement means from the engagement band and freeing the safety handle for free rotation around and relative to the shaft. Preferably, the centering means comprises a pair of springingly resiliently flexible arms on the drive handle, each of which is opposed to a respective wall of the frame. Rotation of the drive handle around its axis in either direction is resisted by one of these arms.
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