Standards for inspection, maintenance and scrapping of main parts of hoisting machinery

Table of Contents

The "Safety Regulations for Lifting Machinery" clearly stipulates the technical requirements for the main accessories of lifting machinery, and stipulates the scrapping standards for various accessories. Our editor will share the "Safety Regulations for Lifting Machinery" 》Inspection, maintenance and scrapping standards for hooks , wire ropes, brakes, wheels and other components.

1. Hook

1.1 The hook shall have the qualification certificate of the manufacturer and other technical certification documents before it can be put into use. Otherwise, it should be tested and found to be qualified before use.
- During use, it should be inspected, repaired and scrapped in accordance with the relevant requirements of this regulation.
1.2 Casting hooks shall not be used for lifting appliances.
1.3 The hook should be equipped with a safety device to prevent accidental unhooking of the lifting weight.
1.4 The surface of the hook should be smooth, free of cracks, sharp corners, burrs, cracks, etc.
1.5 Materials
- a. The hook material should be high-quality low-carbon killed steel or low-carbon alloy steel;
- b. Forging hooks generally use No. 20 steel specified in GB696-65 "High-quality carbon structural steel steel grades and general technical conditions";
- c. Plate hooks generally use A3, C3 steel specified in GB700-79 "Technical Conditions for Common Carbon Structural Steels", or 16Mn steel specified in GB1591-79 "Technical Conditions for Low Alloy Structural Steels".
1.6 Inspection of hook
- a. The hook for the lifting mechanism driven by manpower shall be tested with 1.5 times the rated load as the inspection load;
- b. Power-driven lifting mechanism with hook.
- C. After the hook is removed from the inspection load, the increase in the opening degree should not exceed 0.25% of the original opening degree without any obvious defects or deformation;
- d. The hook should be able to reliably support 2 times the inspection load without falling off;
- e. For hooks with mature technology, stable quality and commonly used materials, the hardness should be checked one by one; for each batch of hooks with the same furnace number, the same tonnage, and the same furnace heat treatment, other mechanical properties except the hardness should be in accordance with the table 3. The requirements of random inspection.
- Use new materials to make hooks. Before the quality is stable, 100% material and mechanical properties of all hooks should be inspected. The inspection results should meet the corresponding material standards.
1.7 The hooks that have passed the inspection shall be marked in the low-stress area with indelible marks and a certificate of conformity shall be issued.
1.8 The hook shall be scrapped when one of the following situations occurs ;
- a. crack;
- b. Dangerous section wear reaches 10% of the original size;
- c. The opening degree is increased by 15% compared to the original size;
- d. The torsion deformation exceeds 10°;
- e. Plastic deformation of the dangerous section or the neck of the hook;
- f. When the plate hook bushing wears up to 50% of the original size, the bushing should be scrapped;
- g. When the plate hook mandrel wears up to 5% of the original size, the mandrel should be scrapped.
1.9 Defects on the hook shall not be repaired by welding.

2 Wire rope

2.1 The wire rope used for hoisting machinery should meet the GB1102-74 "Round Strand Wire Rope" standard, and must have a product inspection certificate.
2.2 The safety factor of the steel wire rope.
2.3 The steel wire ropes should be neatly arranged in order on the drum.
2.4 When the load is supported by multiple steel wire ropes, there should be a balance device for the force of each steel wire rope.
2.5 The hoisting mechanism and luffing mechanism shall not use braided wire ropes. When using other methods to connect the long wire rope, it is necessary to ensure that the connection strength of the joint is not less than 90% of the breaking force of the wire rope.
2.6 For cranes with large lifting heights, it is advisable to use wire ropes that do not rotate and have no tendency to loosen. When other wire ropes are used, there should be devices or measures to prevent the wire ropes and spreaders from rotating.
2.7 When the hook is at the lowest point of the working position, the winding of the steel wire rope on the drum must not be less than 2 turns except for the number of turns of the fixed rope tail.
2.8 High temperature resistant steel wire ropes such as asbestos cores should be used for steel wire ropes for lifting molten or hot metal.
2.9 Safety requirements for the fixed connection of the wire rope ends.
- a. When using a rope clamp to connect, it should meet the requirements of Table 6, and at the same time, it should be ensured that the connection strength is not less than 85% of the breaking force of the wire rope;
- b. When connecting with braiding, the length of the braiding should not be less than 15 times the diameter of the wire rope and not less than 300mm. The connection strength shall not be less than 75% of the breaking force of the wire rope;
- c. When connecting with wedge and wedge sleeve, the wedge sleeve should be made of steel. The connection strength shall not be less than 75% of the breaking force of the wire rope;
- d. When using the taper sleeve casting method to connect, the connection strength should reach the breaking force of the wire rope;
- e. When the aluminum alloy sleeve compression method is used for connection, a reliable process method is used to make the aluminum alloy sleeve and the steel wire rope fit tightly and firmly, and the connection strength should reach the breaking force of the steel wire rope.
2.10 Maintenance of wire rope
- a. The steel wire rope should be prevented from damage, corrosion, or other physical and chemical factors causing performance degradation;
- b. When the wire rope is uncoiled, it should be prevented from knotting or twisting;
- c. When the wire rope is cut, measures should be taken to prevent the strands from spreading;
- d. When installing the wire rope, the wire should not be dragged in an unclean place, nor should it be wound around other objects, and should be prevented from scratching, grinding, rolling and excessive bending;
- e. The wire rope should be kept in good lubrication condition. The lubricant used should meet the requirements of the rope and does not affect the visual inspection. When lubricating, pay special attention to the invisible and inaccessible parts, such as the wire rope at the balance pulley;
- f. When receiving the wire rope, the certificate of conformity of the wire rope must be checked to ensure that the mechanical properties and specifications meet the design requirements;
- g. The steel wire rope used daily should be inspected every day, including the inspection of the fixed connection of the end and the balance pulley, and make a safety judgment.
2.11 The wire rope should be scrapped in accordance with the relevant wire rope inspection and scrapping standards #.
2.12 For wire ropes that meet the GB1102-74 "Round Strand Wire Rope" standard, in terms of broken wires and wear indicators, the following requirements can also be checked for scrap:
- a. When the number of broken wires of the wire rope reaches a certain value;
- b. When the wire rope is corroded or worn, the number of broken wires scrapped in Table 7 should be reduced according to the regulations, and the number of broken wires after the reduction should be scrapped;
- c. The number of scrapped and broken wires of steel wire ropes for lifting hot metal or dangerous goods shall be half of the number of scrapped and broken wires of general crane wire ropes, including the reduction of wire surface abrasion.

3 Welded circular chain for lifting

3.1 The safety factor of the welded circular chain shall not be less than the specified value:
3.2 The material of the welded ring chain should have good weldability and not easy to produce time-effect brittleness. Generally, it is made of 20Mn2 or 20MnV steel specified in YB6-71 "Technical Conditions of Alloy Structural Steel".
3.3 For welded endless chains, 50% of the rated breaking force shall be inspected one by one during the inspection. A certificate of conformity shall be issued for qualified chains, and the following marks shall be made on the chains:
- a. The quality grade mark, the code of the quality grade is clearly stamped or engraved on every 20 link lengths or per meter length (the smaller of the two);
- b. At all ends of the chain, the inspector shall make obvious inspection marks.
3.4 The welded circular chain shall be scrapped when one of the following situations occurs:
- a. crack;
- b. The chain is plastically deformed and stretched to 5% of its original length;
- c. The diameter of the chain ring wears up to 10% of the original diameter.

4 rolls

4.1 The fixing device at the end of the steel wire rope on the reel should have anti-loosening or self-tightening performance. The fixing condition of the end of the wire rope should be checked once a month.
4.2 The end face of the multi-layer winding drum shall have flanges. The flange should be 2 times the diameter of the wire rope or the width of the chain higher than the outermost wire rope or chain. Single-layer winding single-line reels should also meet the above requirements.
4.3 When the reel used for the luffing mechanism of the lifting mechanism adopts a structure without a through support shaft in the cylinder, the cylinder should be made of steel.
4.4 The ratio h1 of the diameter of the drum to the diameter of the wire rope shall not be less than the specified value.
4.5 The reel shall be scrapped when one of the following situations occurs:
- a. crack;
- b. The cylinder wall wears up to 20% of the original wall thickness.

5 pulley

5.1 The ratio h2 of the diameter of the pulley to the diameter of the wire rope shall not be less than the value in Table 10.
- The ratio h of the diameter of the balance pulley to the diameter of the wire rope shall not be less than 0.6h2. For bridge type cranes, h should be equal to h2. For temporary, short-term use of simple, light and small lifting equipment, the value of h2 can be taken as 10, but the minimum should not be less than 8.
5.2 The pulley groove should be smooth and clean, and there should be no defects that damage the wire rope.
5.3 The pulley should have a device to prevent the wire rope from jumping out of the groove.
5.4 Metal cast pulleys shall be scrapped when one of the following situations occurs:
- a. crack;
- b. The uneven wear of the wheel groove reaches 3mm;
- c. The wall thickness of the wheel groove wears up to 20% of the original wall thickness;
- d. The diameter of the bottom of the wheel groove is reduced by 50% of the diameter of the wire rope due to wear;
- e. Other defects that damage the wire rope.

6 Brake

6.1 Power-driven cranes must be equipped with brakes for their lifting, luffing, running and rotating mechanisms.
- The lifting mechanism and luffing mechanism of cranes driven by human power must be equipped with brakes or stoppers.
- The brakes of the lifting mechanism and the luffing mechanism must be normally closed.
6.2 The lifting mechanism should not adopt a structure in which the weight falls freely. If the structure of free falling of heavy objects is adopted, a steerable normally closed brake shall be provided.
6.3 For hoisting hot metal, flammable, explosive and other dangerous goods, as well as the lifting mechanism that may cause major danger or loss after an accident, two sets of brakes should be installed for each set of driving devices.
6.4 The safety factor of each set of brakes;
6.5 The brake should have a heat capacity that meets the operating frequency.
6.6 The brake should have the ability to compensate for the wear of the friction pad of the brake band.
6.7 The actual contact area between the friction pad of the brake band and the brake wheel shall not be less than 70% of the theoretical contact area.
6.8 For the friction pad of the brake band of the band brake, the connection between the end of the backing steel band and the fixed part shall be hinged, and no rigid connection such as bolt connection, riveting, welding, etc. shall be used.
6.9 Manpower control brake, the requirements of applied force and stroke:
6.10 The control parts of the brake, such as pedals, control handles, etc., should have anti-skid performance.
6.11 For cranes in normal use, the brakes should be checked every shift.
6.12 The brake parts shall be scrapped when one of the following situations occurs:
- a. crack;
- b. The thickness of the friction pad of the brake band is worn up to 50% of the original thickness;
- c. Plastic deformation of the spring;
- d. The diameter of the small shaft or shaft hole wears up to 5% of the original diameter.

7 Brake wheel

7.1 The braking friction surface of the brake wheel should not have defects that hinder the braking performance, or be contaminated with oil.
7.2 The brake wheel shall be scrapped when one of the following situations occurs:
- a. crack;
- b. For the brake wheels of the lifting and luffing mechanism, the thickness of the rim wears up to 40% of the original thickness;
- c. For brake wheels of other institutions, the thickness of the rim wears up to 50% of the original thickness;
- d. When the unevenness of the wheel surface reaches 1.5mm, if it can be repaired, the thickness of the wheel rim after repair should meet the requirements of b and c in this article.

8 Wheels working on rails

When one of the following situations occurs, it should be scrapped:

a. crack;
b. The thickness of the rim wears up to 50% of the original thickness;
c. The bending deformation of the rim thickness reaches 20% of the original thickness;
d. The tread thickness wears up to 15% of the original thickness;
e. When the running speed is lower than 50m/min, the ovality reaches 1mm; when the running speed is higher than 50m/min, the ovality reaches 0.5mm.

9 Transmission gear

When one of the following situations occurs, it should be scrapped:

a. crack;
b. Broken tooth
c. When the tooth surface pitting damage reaches 30% of the meshing surface, and the depth reaches 10% of the original tooth thickness;
d. When the wear of the tooth thickness reaches the value listed in Table 13;
e. Lifting hot metal or flammable, explosive and other hazards

12 Hydraulic system

12.1 The hydraulic system should have safety devices to prevent overload and impact.
- When an overflow valve is used, the pressure of the overflow valve should be taken as 110% of the working pressure of the system.
12.2 The hydraulic system should have a good filter or other device to prevent oil pollution.
12.3 In the hydraulic system, there should be measures or devices to prevent the hydraulic motor from being driven by a hoist or boom to overspeed.
12.4 When the hydraulic system is working, the temperature rise of the hydraulic oil should not exceed 40°C.
12.5 When the outrigger cylinder is in the supporting state, the hydraulically controlled check valve must ensure reliable operation. When the basic boom is at the minimum working range and the maximum lifting weight for 15 minutes, the retraction amount of the piston rod of the luffing cylinder and the outrigger cylinder should not be greater than 15mm.
12.6 The balance valve must be connected to the luffing oil cylinder, telescopic boom oil cylinder and hydraulic motor directly or with steel pipes, and must not be connected with hoses.
12.7 The resistance of the manual reversing valve during operation shall be uniform and no impact jump.
12.8 The hydraulic system should use oil according to the design requirements; change the oil regularly according to the instructions.

13 Lubrication

The equipment should have a lubrication diagram and the lubrication points should be marked. The location of the lubrication point should be convenient for safe access, and should be regularly lubricated according to the design requirements during use.

14 Special aids for lifting various items.

There should be a tendency of self-tightening; devices or measures to prevent slipping should be provided if there is no tendency of self-tightening.

The above-mentioned special aids and the steel wire ropes or chains used for suspending and binding should be checked every six months; use twice the allowable load-bearing capacity, and after hanging for 10 minutes, follow the scrap requirements in terms of 2.11 and 3.4. After checking and confirming that it is safe and reliable, you can continue to use it.

15 Commonly used simple lifting equipment

15.1 When a new mast is assembled, the centerline deviation should not be greater than 1/1000 of the total supporting length; for the mast that has been used many times, when reassembled, the centerline deviation and local plastic deformation within each 5m length should not be greater than 40mm ; Within the full length of the mast, the centerline deviation should not be greater than 1/200 of the total supporting length.

The connecting bolts of the assembled mast must be fastened and reliable;

The foundation of the mast should be flat and solid without water accumulation;

The connecting plate of the mast, the head of the mast and the revolving part, etc., should be inspected once a year for deformation, corrosion, riveting, welding or bolting. It should also be checked before each use.

15.2 The embedment of ground anchors should be adapted to the soil conditions on site and the stress conditions of the ground anchors.

The ground anchor pit should not have trenches, underground pipelines, underground cables, etc. within a range of 2m in front and on both sides of the ground anchor pit where the lead wire is exposed to the ground.

The locations and underground parts where the lead wires of ground anchors are exposed to the ground shall be treated with anti-corrosion treatment.

The burial of ground anchors should be level and free from water accumulation.

15.3 Cable wind ropes should be reasonably arranged and evenly tight.

The cable wind rope should be connected to the top of the mast by shackles or other reliable methods; the connection with the ground anchor should be firm and reliable.

When the cable wind rope crosses the highway or street, the overhead height should not be less than 7m.

The safe distance between the cable wind rope and the transmission line should meet the requirements of Table 18.

15.4 The installation and positioning of the winch and the supporting surface should be level and firm.

The center line of the hoist drum and the guide pulley should be straight. The distance between the axis of the reel and the axis of the guide pulley: the facing reel should not be less than 20 times the length of the reel; for the grooved reel, it should not be less than 15 times the length of the reel.

The wire rope should be wound in from below the drum.

Before the hoist works, the wire rope, clutch, brake, ratchet pawl, etc. should be checked for reliability and no abnormalities before starting hoisting.

When heavy objects are suspended for a long time, they should be supported by pawls.

In the event of a sudden power failure during lifting, the main power supply should be disconnected immediately, the handle should be returned to the zero position, and the heavy object should be put down. For those without the ability to manually control the clutch, the site should be monitored to prevent accidents.

15.5 The suspension support points of the chain hoist should be firm, and the load-bearing capacity of the suspension support points should be compatible with the load-bearing capacity of the hoist.

15.6 The structure of the jack should ensure that the rack, screw and plunger cannot escape from the cylinder of the base at the maximum lifting height.

The rack, screw, and plunger shall not lose stability under the test load in Table 15.

When the jack is placed on the supporting surface at an angle of 6° to the horizontal, the rack, screw, and plunger are at the maximum lifting height, and the center of the tip is subjected to the rated load perpendicular to the horizontal plane, and no less than 3min, there must be no plasticity in each part. Deformation or other abnormal phenomena.

When using the jack, the handle should not be lengthened.

The jack base should be flat, firm and complete.

The support of the jack should be stable and the foundation should be level and solid.

When multiple jacks are used together, the actions of each jack should be synchronized and balanced.