US Patent 7533870 Pulley

A pulley comprises a pulley frame having two sides. A pulley wheel is located between the two sides. The pulley wheel is rotatably supported by the pulley frame. At least one of the sides is mounted for movement away from the pulley wheel to provide a gap between the moveable side and the wheel for releasing a line from the pulley. A latch is provided for releasably retaining the at least one side in the closed position to confine a line between the two sides. The latch is adapted to release the movable side when a predetermined force is applied to the latch. A retainer responsive to the release of the latch holds the moveable side in the open position when released.