Main purpose of crane using rope pulleys, rope changes the direction of movement and efforts to achieve their goals.
Pulleys on the basis of different materials, cast iron pulleys, steel wheel, nylon wheel and aluminum pulleys. Grey cast iron and nodular cast iron pulley. Good processing properties of gray iron, wire rope wear small, but easy to break up edges, shorter life expectancy, and more low level, strength and toughness nodular cast iron a little over cast iron.
Pulley according to the role can be divided into a fixed pulley, pulley, the pulley, the pulley. Fixed pulley center pivot is fixed, its role is to change the cord or pull direction. The central hub and the pulley with lifting or moving heavy objects, it's role is to work. Rope pulley through a number of activities, fixed pulleys, dynamic, taking into account the characteristics of the two pulleys, not only changed the direction of the force, but also achieve the objective of saving. Guide pulley is used to change the direction of the rope, rope is usually installed in the corner.