Jib lifting and lowering mechanism - uses two cables attached to quadrant, also wound onto and unwound from winch drum

摘要

The jib lifting and lowering mechanism is for e.g. a jib (1) carrying an endless conveyor and it includes a chain, rope or cable drive operated by a winch (5). The winch drum has two cables (6) attached to an anchorage point (10) on the periphery of a wheel (8a) shaped as a quarter of a circle. The two other ends of the cable are anchored to the winch drum so that as one cable unwinds, the other winds onto the drum. The shafts of the wheel and winch drum are parallel and the cables also pass round a guide wheel (9) with its spindle at right angles to them. Similarly, a winch and double cable system can be used to rotate a crane turn table or similar.