Maintenance of steel structure components

1. Strictly implement the scrapping standard of crane steel structures.

2. Check the metal fatigue strength, weld crack, structural deformation, damage and other conditions of the main stressed structural members. Check the key welds of the main stressed structural members and the base metal of the welding heat affected zone. If any abnormality is found, it shall be handled. The inspection of structural members shall be carried out according to the following procedures.

(A) Daily inspection: tower crane shall be inspected once every 80 hours. The tower crane driver shall check the fastening of bolts at all connection parts during shift handover, and timely tighten them if they are loose.

(B) When the tower crane makes abnormal noise, or misoperates, or the tower crane safety protection device fails, check and record.

(C) When a project is completed and the tower crane is disassembled, engineering technicians and professional maintenance personnel shall conduct a detailed inspection and make records.

3. Try to prevent structural members from deformation and collision damage during transportation.

4. Paint once every six months to one year. Rust, oil stain and other dirt on the metal surface shall be removed before painting.

Maintenance of operating mechanism

1. Daily maintenance

(1) Keep all institutions clean and clean all dust in time;

(2) Check the oil volume of each reducer. If it is lower than the specified oil level, add oil in time;

(3) Check whether the air vent plug of each reducer can exhaust freely. If it is blocked, it shall be unblocked in time;

(4) Check the efficiency of each brake, and timely adjust it if it is not sensitive and reliable;

(5) Check the bolts at each connection, and timely tighten and supplement them in case of looseness and falling off;

(6) Check various safety devices, and timely adjust them in case of failure;

(7) Check the steel wire ropes and pulleys at all parts, and timely handle any excessive wear found;

(8) Check the lubrication of all lubricating parts and add lubricating grease in time.

2. Minor repair (after 1000 hours of tower crane operation)

(1) Carry out daily maintenance;

(2) Disassemble, check and clean the gear of the reducer, and adjust the backlash;

(3) Clean the gear of open transmission and apply grease after adjustment;

(4) Check and adjust slewing bearing device;

(5) Check and adjust the brake and safety device;

(6) Check the wear of hooks, pulleys and wire ropes, and adjust, repair and change them if necessary.

3. Medium maintenance (after 4000 hours of tower crane operation)

(1) Carry out various work of minor repair;

(2) Repair or change the damaged parts of each coupling;

(3) Repair or replace the brake shoe;

(4) Replace wire rope, pulley, etc;

(5) Check all connecting bolts of slewing ring and replace them if necessary. Note: high-strength bolts shall be used for replacement;

(6) Rust removal and painting.

4. Overhaul (after 8000 hours of tower crane operation)

(1) Carry out various work of minor and medium maintenance;

(2) Repair or replace the brake wheel and brake;

(3) Repair or replace the reducer assembly;

(4) Repair or replace the slewing ring assembly.

1. Daily maintenance

(1) Keep all institutions clean and clean all dust in time;

(2) Check the oil volume of each reducer. If it is lower than the specified oil level, add oil in time;

(3) Check whether the air vent plug of each reducer can exhaust freely. If it is blocked, it shall be unblocked in time;

(4) Check the efficiency of each brake, and timely adjust it if it is not sensitive and reliable;

(5) Check the bolts at each connection, and timely tighten and supplement them in case of looseness and falling off;

(6) Check various safety devices, and timely adjust them in case of failure;

(7) Check the steel wire ropes and pulleys at all parts, and timely handle any excessive wear found;

(8) Check the lubrication of all lubricating parts and add lubricating grease in time.

2. Minor repair (after 1000 hours of tower crane operation)

(1) Carry out daily maintenance;

(2) Disassemble, check and clean the gear of the reducer, and adjust the backlash;

(3) Clean the gear of open transmission and apply grease after adjustment;

(4) Check and adjust slewing bearing device;

(5) Check and adjust the brake and safety device;

(6) Check the wear of hooks, pulleys and wire ropes, and adjust, repair and change them if necessary.

3. Medium maintenance (after 4000 hours of tower crane operation)

(1) Carry out various work of minor repair;

(2) Repair or change the damaged parts of each coupling;

(3) Repair or replace the brake shoe;

(4) Replace wire rope, pulley, etc;

(5) Check all connecting bolts of slewing ring and replace them if necessary. Note: high-strength bolts shall be used for replacement;

(6) Rust removal and painting.

4. Overhaul (after 8000 hours of tower crane operation)

(1) Carry out various work of minor and medium maintenance;

(2) Repair or replace the brake wheel and brake;

(3) Repair or replace the reducer assembly;

(4) Repair or replace the slewing ring assembly.

1. Daily maintenance

(1) Keep all institutions clean and clean all dust in time;

(2) Check the oil volume of each reducer. If it is lower than the specified oil level, add oil in time;

(3) Check whether the air vent plug of each reducer can exhaust freely. If it is blocked, it shall be unblocked in time;

(4) Check the efficiency of each brake, and timely adjust it if it is not sensitive and reliable;

(5) Check the bolts at each connection, and timely tighten and supplement them in case of looseness and falling off;

(6) Check various safety devices, and timely adjust them in case of failure;

(7) Check the steel wire ropes and pulleys at all parts, and timely handle any excessive wear found;

(8) Check the lubrication of all lubricating parts and add lubricating grease in time.

2. Minor repair (after 1000 hours of tower crane operation)

(1) Carry out daily maintenance;

(2) Disassemble, check and clean the gear of the reducer, and adjust the backlash;

(3) Clean the gear of open transmission and apply grease after adjustment;

(4) Check and adjust slewing bearing device;

(5) Check and adjust the brake and safety device;

(6) Check the wear of hooks, pulleys and wire ropes, and adjust, repair and change them if necessary.

3. Medium maintenance (after 4000 hours of tower crane operation)

(1) Carry out various work of minor repair;

(2) Repair or change the damaged parts of each coupling;

(3) Repair or replace the brake shoe;

(4) Replace wire rope, pulley, etc;

(5) Check all connecting bolts of slewing ring and replace them if necessary. Note: high-strength bolts shall be used for replacement;

(6) Rust removal and painting.

4. Overhaul (after 8000 hours of tower crane operation)

(1) Carry out various work of minor and medium maintenance;

(2) Repair or replace the brake wheel and brake;

(3) Repair or replace the reducer assembly;

(4) Repair or replace the slewing ring assembly.

Wire rope and its maintenance

1. During the use of steel wire rope, it shall be prevented from looping, twisting, bending or adhering to foreign matters, and from friction with machinery or other foreign matters.

2. After the tower crane is installed (before use), the steel wire rope shall be lubricated, and graphite grease shall be applied once, and then the steel wire rope shall be lubricated according to the "Crane Lubrication Table".

3. The overall design of tower crane does not allow the steel wire rope to have an indefinite life, and it shall be scrapped under one of the following circumstances:

a. Wire rope 6 × 19-d (d wire rope diameter) The number of broken wires exceeds 5 within 6d and 10 within 30d.

b. Wire rope 6 × 37-d (d wire rope diameter) has more than 10 broken wires within 6d and more than 19 broken wires within 30d.

c. The steel wire ropes shall be scrapped even if the number of broken wires does not exceed 5 within 6d.

d. Although the wire of the wire rope is not broken, the wire rope is worn to 40% of its diameter, or the wire rope is reduced by 7% or more relative to the nominal diameter, or the wire rope is obviously bent.

e. The wire rope loses its normal shape, resulting in deformities, such as waves, cage distortion, rope strand extrusion, wire extrusion, local rope diameter enlargement, kinking, local rope diameter reduction, partial flattening and bending.

f. When the diameter of steel wire rope is subjected to special thermal action, and there is recognizable color on the outside.

Note: When lifting molten or hot metals, acid solutions, explosives and inflammables, the scrapping quantity of broken wires of wire ropes will be halved. The situations not mentioned in this manual shall be subject to GB5972.

Maintenance of other main components

1. Brake parts shall be scrapped in any of the following cases:

(1) Cracks;

(2) The wear of brake pad friction lining reaches 50% of the thickness of raw materials;

(3) The wear of the brake wheel surface reaches 5mm~2mm;

(4) The spring has plastic deformation;

(5) The empty stroke of the lever system exceeds its rated stroke by about 10%.

2. The hook shall not be repaired and shall be scrapped under any of the following circumstances:

(1) Observe the surface with a 20 times magnifying glass for cracks and breaks;

(2) Dangerous sections such as coupler tail and threaded part and hook bar have permanent deformation;

(3) The wear amount of the section at the lanyard exceeds 10% of the original height;

(4) The wear of spindle exceeds 5% of its diameter;

(5) The opening degree is 15% higher than the original size.

3. The drum and pulley shall be scrapped in any of the following cases:

(1) Cracks and rim damage;

(2) The wear of drum wall reaches 10% of the original wall thickness;

(3) The wear of pulley rope groove bottom exceeds 25% of the corresponding wire rope diameter.

4. The wheel shall be scrapped in any of the following cases:

(1) Cracks;

(2) The wear amount of wheel tread thickness reaches 15% of the original thickness;

(3) The wear amount of wheel flange thickness reaches 50% of the original thickness.

5. The operator must always check the sensitivity and effectiveness of the safety limiter. If it is found to be out of order, it should be adjusted or repaired in time. It is not allowed to remove the limiter circuit.