| 摘要 |
A self-retractable lifeline ("SRL") having the combination of an active fall arrest braking system and a passive restraint distance limiting mechanism that allows a user to pretension and preset the distance that its cable is capable of paying out. The SRL's cable limiting mechanism includes a pretension assembly, which may include a pair of aligned plates and an actuator that temporarily mobilizes an arbor when the lever is opened. The arbor is affixed to the SRL housing and to an interior of a power spring that rewinds the cable back into the housing when the cable is paid out. The other end of the arbor is in a mechanical relationship to one of the aligned plates that prohibits rotational movement of the arbor when the aligned plates are engaged but allows rotational movement of the arbor when the aligned plates are temporarily disengaged. When pretensioning of the power spring is desired, the actuator is activated and a tension is applied onto at least one of the aligned plates to temporarily disengage them and to temporarily mobilize the arbor. As the arbor is affixed to the interior of the power spring, the number of rotational turns that the arbor makes causes the power spring to "pretension" and thereby limits the maximum cable payout by the number of turns. The active braking system for fall arrest is independent of the cable limiting mechanism. The SRL may optionally include a mechanism affixed to the opposite end of the arbor to reduce or eliminate overtensioning due to human error.
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