Functions and scrapping conditions of the pulley a

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Functions and scrapping conditions of crane pulley and pulley block

what are the functions of pulley and pulley block

the pulley supports and guides the rope movement, playing two roles of guidance and balance. The pulley block is composed of a certain number of moving pulleys and fixed pulleys. It has the characteristics of both moving and fixed pulleys. The pulleys are divided into fixed pulleys and moving pulleys. The fixed pulley only changes the direction of the force. Moving pulley can save labor. Therefore, the pulley block can change the direction of the force and save labor. And it can be used as a deceleration device, so it is impossible to calculate the fracture bending strength or speed increase device. When the lifting capacity is large, the pulley block with a larger ratio should be used to reduce the tension of the steel wire rope; When the lifting weight is light, the pulley block with smaller magnification should be used to reduce the number of threading and winding of the steel wire rope and improve the work efficiency. The pulley block composed of steel wire rope, fixed pulley and moving pulley is an important part of the crane lifting mechanism. According to the function of the pulley, it is divided into labor-saving pulley block and speed increasing pulley block. Pulley block is also divided into shear force. There are single pulley block and double pulley block, which step up a new step every year. It can be seen from the above that the experimental machine is a kind of equipment that plays a very important role in production activities

what conditions should the pulley be scrapped

if one of the following conditions exists, the pulley should be scrapped:

① crack (repair welding is not allowed)

② uneven wear of wheel groove reaches 3mm

③ the wear of the wheel groove wall thickness reaches 20% of the original size

④ the diameter at the bottom of the wheel groove is reduced by 50% of the diameter of the steel wire rope due to wear

⑤ others that meet the scrapping conditions

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