| 摘要 |
A gate for controllably inhibiting passage through a controlled zone which includes a rotating arm, the rotation of which may be prevented by a solenoid-coupled pawl which engages a gear-like multiposition detent member coupled to a shaft on which the arm is mounted. In the event excessive force is applied to the arm when thus locked to enable emergency egress, a clutch allows rotation of the shaft, and of the arm, with respect to the detent member. The arm may be automatically repositioned to enable a new position about the periphery of the detent member to become engageable by the pawl.
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