Pulley of the blocks and threaded through the two sets of pulleys form a block and tackle. A block and tackle is assembled so one block is attached to fixed mounting point and the other is attached to the moving load. The ideal mechanical advantage of the block and tackle is equal to the number of parts of the rope that support the moving block. In the diagram on the right the ideal mechanical advantage of each of the block and tackle assemblies shown is as follows: A rope and pulley system—that is, a block and tackle—is characterised by the use
Wire rope spooling technology its behaviour and affects lifespan. Fleet angle should be between 0.25° and 1.25°, depending on the rope construction. The fleet angle can be varied by moving the first sheave closer to or further away from the drum. If the sheave is too close to the drum, the fleet angle will be greater than 1.25°; if it is too far away, the fleet angle will be less than 0.25°. Sometimes it is not possible to achieve the optimum fleet angle. Where there is no space to rig a sheave the requisite distance from the drum, two additional spooling devices are available.