Classification of pulleys for medium and heavy industry cranes

Nowadays, social and economic development is getting faster and faster, which directly accelerates the development of the engineering construction industry. As one of the main equipment in engineering construction, the crane's working intensity is getting stronger and stronger. In the case of long-term intensive work cycle, it will cause certain damage to the crane itself and various components. This requires us to consider how to reduce the workload of the crane.

The main purpose of using pulleys in cranes is to thread the wire rope, change the direction of movement of the wire rope, and achieve labor saving. Below, the technical personnel of medium and heavy industry will introduce the types of pulleys to us: Pulleys can be divided into fixed pulleys, movable pulleys, pulley blocks, guide pulleys, etc. according to their different functions.
In hoisting operations, if only the fixed pulley is used, it can only change the direction of the force and cannot save labor. Although using only the movable pulley can save labor, it cannot change the direction of the force, and it also needs to save labor. Therefore, the fixed pulley and the movable pulley must be connected together to form a pulley block to meet the requirements of lifting and transportation operations.

Pulleys are divided into cast iron pulleys, cast steel pulleys, nylon pulleys and aluminum alloy pulleys according to their different materials. Cast iron pulleys are divided into gray cast iron pulleys and ductile iron pulleys. Gray cast iron pulleys have good process performance and little wear on the wire rope, but they are easy to break the rim and have a very short life. They are mostly used in lower working levels; ductile iron pulleys have higher strength and impact toughness than gray cast iron pulleys, so they can be used In cranes with high working level.
Cast steel pulleys have higher strength and impact toughness, but their craftsmanship is slightly worse. Due to the hard surface, it causes serious wear and tear on the wire rope, so it is mostly used in high-level working conditions. Large-size pulleys mostly use welded pulleys, which are roughly the same as cast steel pulleys, but are light in weight, and some can be reduced to about a quarter. At present, nylon pulleys and aluminum alloy pulleys have been widely used on cranes. Nylon pulleys are light and wear-resistant, but have low stiffness; aluminum alloy pulleys have low hardness and have little wear on the wire rope.