| 摘要 |
A safety system which permits the free movement of the user, assists the ascent of the user and provides a reduced, controlled rate of descent in the event of an emergency descent or a fall, includes a cable attachable at one end to the user and secured at the other end to a moveable counterweight assembly. Intermediate its ends the cable passes over a pulley in a controlled descent device which also includes a centrifugally-actuated clutch coupling the pulley to a speed-multiplying gearing system and a centrifugally-operated braking assembly. Under normal-use conditions, the pulley is rotated at sufficiently low speeds to preclude engagement of the clutch, and the user has free movement, with a component of the counterweight assisting the ascent of the user. In the event of a rapid rate of descent, the increased rotational speed of the pulley is coupled to and actuates the braking assembly to reduce the rotation of the pulley and slow the descent to a lower, controlled rate. Descent may be vertically or at an angle with a spring pulley and an angled descent cable. The cable may be disposed on the pulley in different arrangements, and the pulley may be provided with alternate groove configurations. The pulley may be coupled to the braking assembly without an intervening clutch.
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