Classification and function of lifting tackle and pulley block

Hoisting tackle, also known as pulley and pulley block, is a kind of sling. The classification of pulleys is as follows:

1. According to the production material, there are wooden pulleys and steel pulleys.

2. According to the method of use, there are fixed pulleys, movable pulleys, and pulley blocks composed of movable and fixed pulleys.

3. According to the number of pulleys, there are single pulley, double pulley, three pulleys, four pulleys and more.

4. According to its functions, there are guiding pulleys and balance pulleys.

5. According to the connection mode, there are hook type, chain link type, ring type and beam type.

The role of hoisting tackle and pulley block: fixed pulley is used to support the rope movement, usually used as a guide pulley and balance pulley, it can change the direction of the rope force, but can not change the rope speed, and can not save effort. When using movable pulleys, because the equipment or components are shared by two steel wire ropes, the force of each steel wire rope is 50% of the weight of the heavy object. The guide pulley is also called the door opening pulley. Like the fixed pulley, it can only change the direction of the wire rope. When in use, the middle part of the wire rope is put in from the opening, and the guide pulley is usually used at the foot of the lifting mast. The pulley block is composed of a certain number of movable pulleys and fixed pulleys through ropes. It has the characteristics of moving and fixed pulleys, and at the same time it can change the direction of the force, and it is labor-saving. If multiple sets of pulleys are used to lift equipment or components, the traction will be smaller.