Pulley Group

A pulley is a set of simple tool consisted of one or more wheels over which a rope can be looped for the purpose of labor saving and movement direction changing. Pulleys can be divided into crown block/ fixed pulley and fall block /movable pulley based on functions of pulleys while based on materials, pulley blocks can be classified into cast iron pulley, cast steel pulley, nylon pulley, and aluminum pulleys, etc.

Types and Features of pulley block

1) On pulley functions

According to different functions, pulleys can be divided in crown block/ fixed pulley and fall block/ moveable pulley.

Crown pulley/ fixed pulley used in the lifting operations is meant to change the moving direction of wire rope while the fall block / moveable pulley is used to save the effort and energy. Therefore, they are coordinated to consist the pulley block which can save energy and change the direction of movement at same time.

pulley functions

2) On pulley materials

Based on different materials, pulleys can be classified into cast iron pulley, cast steel pulley, nylon pulley, and aluminum pulleys.

Cast iron pulley

Cast iron pulleys can be further divided into gray cast iron pulley and nodular cast iron pulley. The gray cast iron pulley has the features of good performance, little wear to wire rope which is widely used in light working duty cranes. On the contrast, the nodular cast iron pulleys can stand more collision than that of gray cast iron and they are widely used in the heavy duty cranes.

Cast steel pulley

Cast steel pulley has the features of higher strength and toughness but less manufacturability. Due do the high hardness on the surface, cast steel pulley may cause big wear damage to wire rope and are usually adopted by heavy duty conditions. As the large diameter pulley is concerned, the cast steel pulley are favored because the welding capability and comparatively light weight.