Block and tackle systems. A block is a set of pulleys or sheaves mounted on a single frame. An assembly of blocks with a rope threaded through the pulleys is called tackle. A block and tackle system amplifies the tension force in the rope to lift heavy loads. They are common on boats and sailing ships, where tasks are often performed manually. In the diagram shown here, the number of rope sections of the tackles shown is as follows: Note that the gun tackle, double tackle and threefold purchase all have the same number of pulleys in both blocks (one, two and three,
Wire rope spooling technology pattern is engineered to suit the rope's length, diameter and construction type. In any multi-layer spooling application it is important that when the rope is first installed on the drum, it is done so under tension to avoid any slack on inner layers that can be crushed or nicked against the groove walls by outer layers. The fleet angle is defined as the largest angle of the rope between the first sheave and the drum flange, relative to the centre line of the drum. With all type of drums, the rope is subject to a fleet angle which impacts on