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What are the requirements for wire pay-off blocks?


1. Basic parameters of pay-off block

1. The basic parameters of the pay-off block mainly include: rated working load, the diameter of the bottom of the pulley groove, the radius of the bottom of the pulley groove (hereinafter referred to as the radius of the bottom of the pulley), the width of the pulley, the gap between the two sides of the pulley, and the effective height of the passing object;

2. The basic parameter series and size of pay-off pulley and pay-off block are determined by referring to the common series of R20 and R40 in GB/T 321 and GB/T 2822;

3. The rated working load of the single-wheel pay-off block (set up clue pulley) : generally refers to the maximum vertical load calculated by the tension acting on the pulley when the corresponding clue is at a certain envelope Angle. The rated working load of multi-wheel pay-off block: generally refers to the sum of the maximum vertical load of the corresponding lead acting on each pulley at the same time under a certain envelope Angle.

2. Technical requirements

1. Basic requirements

(1) The design, manufacture and inspection of the pay-off block shall comply with the requirements of this standard and DL/T875 standard, and shall be manufactured in accordance with the drawings and technical documents approved by the prescribed procedures;

(2) For different voltage levels and different lead specifications, the main technical parameters of the pay-off pulley should be selected according to this standard;

(3) The safety factor of pay-off pulley and block should not be less than 3;

(4) Pay-off block should be easy to maintain and maintain;

(5) The pay-off pulley should have a protective device to prevent the pulley from being damaged during transportation.

2. Performance requirements

(1) The friction coefficient of the wire pay-off pulley should not be greater than 1.015, and the friction coefficient refers to the ratio of the tension between the outgoing side and the incoming side of the measured pulley;

(2) The pay-off block should be able to pass the traction plate, the splicing tube protection device and the rotary connector smoothly;

(3) The surface of the pulley groove should not damage the guide rope and the traction rope, and should have a certain service life;

(4) For the same pulley through different kinds of clues, its surface should not damage the clues, it is appropriate to use a glue pulley or other protective devices;

(5) The grease of the rolling bearing should be selected according to the ambient temperature of the work, and the appropriate amount of oil injection should be controlled, and the friction coefficient of the pulley should not be increased;

(6) Electrical performance

a. The grounding block and the grounding pay-off block should ensure that the wires are well grounded during the laying process;

b. The grounding block and grounding pay-off block should not have hidden trouble, otherwise they should be repaired or replaced.

3. Appearance quality of pay-off block

(1) The appearance should be smooth and smooth, without sharp corners and sharp edges;

(2) The parts should not have trachoma, pores, cracks and porosity and other defects;

(3) The weld should be beautiful and smooth, without burrs, missed welding, cracks, folding, overheating, overburning and other local defects that reduce strength;

(4) The rubber surface should not have bubbles, pores, water ripples and other defects;

(5) Galvanized surface should be smooth, uniform coating;

(6)MC nylon pulley should be made of standard centrifugal casting process, there should be no flash, bubbles, shrinkage holes and other casting defects.

3. Test method

1. Check appearance

(1) Use visual inspection methods to check blocks, pulleys and other major parts;

(2) In the state of no load, rotate by hand, hit the pulley and other moving parts of the metal rod, observe the rotation of the pulley and check the quality of the components.

2. Structure size check

(1) Pulley size inspection: with an accuracy of 0.02mm depth vernier ruler, π ruler, vernier caliper, universal Angle ruler with an accuracy of 2', and a precision of 1mm radius template for measurement;

(2) Pulley runout error check: use a dial indicator with an accuracy of 0.01mm to measure. The magnetic seat plate is fixed in the appropriate position of the plate or block body, so that the contact head and the measured point of the pulley are in good contact, and the difference between the maximum value and the minimum value measured is the runout error of the pulley diameter and the end face.

The above is about the parameters, technical requirements and inspection methods of the industry introduction, I hope that through the above content can let you have a further understanding and understanding of the wire pulley industry.

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