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.
1. A pulley comprising:
a pulley frame comprising two sides;
a pulley wheel between the two sides, the pulley wheel being rotatably supported by the pulley frame;
a pivoting means pivotally connecting at least one of the two sides to the pulley frame for pivoting the at least one side between a closed position for confining a line between the two sides and an open position for releasing the line from the pulley;
a latch for releasably retaining the at least one side in the closed position, the latch being adapted to release the at least one side when a predetermined force is applied to the latch; and
a biasing means associated with the at least one side which biases the at least one side to the open position when the latch is released.
2. The pulley according to claim 1 wherein the biasing means is integral to the pivoting means.
3. The pulley according to claim 1 wherein the pivoting means comprises a hinge including a hinge pin and the biasing means comprises an axial torsion spring mounted on the hinge pin.
4. The pulley according to claim 1 wherein the biasing means comprises at least one elastic cord connected between the at least one side and the pulley frame wherein the at least one elastic cord is stretched in the closed position and contracted in the open position.
5. The pulley according to claim 4 wherein at least two holes are defined through the at least one side and the elastic cord is interconnected to the at least one side through the at least two holes.
6. The pulley according to claim 4 or claim 5 wherein the elastic cord is held within the frame by being clamped between elements of the frame.
7. The pulley according to claim 1 wherein the latch is self-opening upon application of the predetermined force by the line or a breaker on the line.
8. The pulley according to claim 1 further comprising:
a lock movable between a locked position and an unlocked position wherein in the locked position the at least one side is prevented from moving to the open position when the predetermined force is applied and in the unlocked position the at least one side is movable to the open position.
9. A pulley comprising
a pulley frame comprising two sides;
a pulley wheel between the two sides, the pulley wheel being rotatably supported by the pulley frame;
a pivoting means pivotally connecting at least one of the two sides to the pulley frame for pivoting the at least one side between an open position and a closed position;
a latch for releasably retaining the at least one side in the closed position to confine a line between the two sides, the latch being adapted to release the at least one side when a predetermined force is applied; and
a lock movable between a locked position and an unlocked position wherein in the locked position the at least one side is prevented from moving to the open position when the predetermined force is applied and in the unlocked position the at least one side is movable to the open position.
10. The pulley according to claim 9 wherein the lock is independent of the latch.
11. The pulley according to claim 9 wherein the lock is accessible from both outer sides of the pulley.
12. The pulley according to claim 9 wherein the lock comprises a movable part and a protruding element, the movable part defining a lip adapted to engage the protruding element in the locked position, the movable part and the protruding element forming part of respective ones of the frame and the at least one side.
13. The pulley according to claim 12 wherein the movable part is movable in a direction perpendicular to a rotational axis of the pulley wheel and a pivoting axis of the at least one side.
14. The pulley according to claim 12 wherein the movable part comprises a threaded knob which is rotatable to move axially between the locked position and the unlocked position.
15. The pulley according to claim 14 wherein the threaded knob projects through openings defined in the two sides.
16. The pulley according to claim 15 wherein the shape of the openings define limits of travel of the threaded knob.
17. The pulley according to claim 14 wherein the lip is defined by a groove in the knob.
18. The pulley according to claim 12 wherein the protruding element comprises a portion of one of the sides which protrudes into the opening.
19. The pulley according to claim 12 wherein the lock further comprises an override movable between an activated position and an unactivated position wherein in the activated position the lock is prevented from moving and in the unactivated position the lock is movable.
20. A pulley comprising:
a pulley frame comprising two sides;
a pulley wheel between the two sides, the pulley wheel being rotatably supported by the pulley frame;
at least one of the sides being 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 for releasably retaining the at least one side in the closed position to confine a line between the two sides, the latch being adapted to release the moveable side when a predetermined force is applied to the latch; and
a retainer responsive to the release of the latch to hold the moveable side in the open position.
21. The pulley according to claim 20 further comprising:
a lock movable between a locked position and an unlocked position wherein in the locked position the movable side is prevented from moving to the open position when the predetermined force is applied and in the unlocked position the moveable side is movable to the open position.
22. The pulley according to claim 20 wherein the retainer moves when the latch is released.
23. The pulley according to claim 20 wherein the retainer comprises at least one pair of magnets of opposite polarity.