Self-braking pulley

Abstract

A self-braking pulley is disclosed for controlling a rate of extraction of a tether coupled with the pulley. The pulley comprises a pulley housing, a spool for receiving a tether, the spool being configured to rotate about a first axis, relative to the pulley housing, and a piston assembly comprising a chamber having a first and second chamber portion which are rotationally locked to the housing. The piston assembly further comprises a fluid disposed within the chamber, a piston which is arranged to move within the chamber along a second axis between the first and second chamber portions and at least one bore formed within the piston for fluidly coupling the first and second chamber portions. The pulley further comprises means for coupling rotational motion of the spool with reciprocating motion of the piston back and forth between the chamber portions, to cause the fluid to transfer between the chamber portions via the at least one bore as the spool rotates.

Dependencies are inferred from the claim text.