Sheave Sheave A sheave () is a pulley with a grooved wheel for holding a belt, wire rope, or rope. The grooved wheel spins on an axle or bearing inside the frame of the block. This allows the wire or rope to move freely minimizing friction and wear on the cable. Sheaves can be used to redirect a cable or rope, lift loads, and transmit power. The words "sheave" and "pulley" are sometimes used interchangeably. A sheave can also refer to a pulley which has an adjustable operating diameter for use with a mechanical belt. This is accomplished by constructing the
Block and tackle tackle the direction of the pulling force is reversed though the mechanical advantage remains the same, Diagram 3a. This is an example of the Luff tackle. The decision of which to use depends on pragmatic considerations for the total ergonomics of working with a particular situation. Reeving to advantage is the most efficient use of equipment and resources. For example, if the load is to be hauled parallel to the ground, reeving to advantage enables the pulling force to be in the direction of the load movement, allowing obstacles to be managed more easily. Reeving to disadvantage adds an extra