Pulleys and pulley sheaves and pulleys are often used in the lifting. 1, pulley sheaves and model from the weight pulleys: Q = 0.1nD2 Q --- safe lifting weight pulley (kg); D --- pulley diameter (mm); d --- pulley number. Pulley applications (illustration) (1) fixed pulley (2) movable pulley (3) guide pulley 2, pulley block (1) effort pulley (2) to wear around the stationary special lifting equipment industry, business case rope currently engaged in special lifting equipment industry has three major business classification: lifting individual enterprises, state-owned crane company, foreign crane company. Lifting individual enterprises are operating relatively small lifting equipment lifting machine tools, but with the development of the market lifting equipment is installed, there are many private companies began to purchase large lifting equipment; lifting state-owned energy company mainly to the type of construction industry Construction and medium-sized enterprises to provide lifting equipment, the domestic market is relatively mature, is now actively expand foreign markets lifting equipment, such as Sany, XCMG and other enterprises; foreign hoisting equipment company also actively open the Chinese market, lifting equipment, and strength, but requires a process to adapt to the Chinese market for these multinational companies in China's development is not easy. Lifting machine tools, Shandong Lu preferred (certified), Yantai Shandong lifting equipment provided by Lu mechanical equipment installation Limited. Shandong Lu Machinery Installation Co., Ltd. (www.sdlzqz.com) Shandong Jinan, industrial maintenance, installation of leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Lifting leadership in Shandong Lu staff warmly welcome all inquiries negotiations to create Shandong Lu lifting a better future.