Lifting Crane Failure and Troubleshooting 1：Part Article

01 Mar, 2016

In the lifting crane use process, mechanical parts, components, electrical control and hydraulic system components will be worn and lead to failure. Possible causes for the same fault of lifting cranes are not one to one corresponding relationship. So in order to make serious analysis of lifting crane faults and accurately find the real causes of the malfunction, and take elimination method corresponding to the exclusion of the lifting crane fault point to restore the technical performance.

Lifting crane troubleshooting

Lifting crane failure and troubleshooting 1：Part Article

A. Lifting crane forging hook failure and damage condition:

1. The fatigue crack of the hook surface.
2. The opening and the dangerous section of wear.
3. Plastic deformation of bending position and opening parts.
The causes and consequences:
1. Overload, extended use, material defects.
2. Seriously weaken the strength, easy breaking hook, caused the accident.
3. The long-term overload, due to fatigue.
Solving Method:
1. Crack is found and replaced.
2. The wear volume of more than 10% dangerous sections, replacement.
3. Immediate replacement.

B. Lifting crane laminated hook failure and damage condition:

1. Hook deformation.
2. Surface with fatigue crack
3. Pin shaft wear volume of more than 3%~5% of the nominal diameter
4. Earrings have cracks and burrs
5. Earrings bushing wear volume is amount to 50% of the original thickness
The causes and consequences:
1. Long term overload, easy folding hook.
2. Extended, overload, hook damage
3. Hook off
4. Earring fracture
5. Stress situation is bad
Solving Method:
1. Replacement
2. Replacement
3. Replacement
4. Replacement
5. Replacement

C. The wire rope failure of lifting crane and damage condition:

1. Broken wire, broken strands, tie, wear
The causes and consequences:
1. Sudden broken rope.
Solving Method:
1. Broken and wear wire according to the standards of lifting crane to be replaced; broken strands and tie should stop using.

D. Pulley failure and damage condition:

1. Pulley groove wear is not uniform.
2. Pulley spindle wear volume of more than 3%~5% of the nominal diameter
3. Pulley can’t turn
4. Pulley tilt and loose
5. Pulley crack or rim fracture
The causes and consequences:
1. Uneven material and installation of substandard requirements, rope and pulley contact bad
2. Spindle damage
3. The spindle and the steel wire rope wear increased
4. Axis positioning loose parts or steel wire rope quit from groove
5. Pulley damage
Solving Method:
1. Pulley groove wall wear volume is amount to 1/10 of the original thickness and radial wear volume is amount to 1/4 of the diameter of the rope, replacement.
2. Replacement
3. Cleaning, maintenance and strengthen the lubrication
4. Maintenance
5. Replacement

E. Lifting crane drum failure and damage condition:

1. Drum fatigue crack
2. Shaft and key wear
3. Drum rope grove wear volume is amount to 15%~20% of the original thickness
The causes and consequences:
1. Drum rupture
2. The shaft is cut, resulting in heavy fall
3. Drum strength weakened, easily broken; wire rope winding chaos.
Solving Method:
1. Replace drum
2. Stop using immediately and service shaft and key
3. Replace drum

F. Transmission shaft failure and damage condition:

1. Crack
2. Shaft bending over 0.5 mm/m.
3. Key groove damage
The causes and consequences:
1. Poor materials and improper heat treatment, leading to the damage of the shaft
2. Shaft neck wear, impact rotation, vibration
3. Can’t transfer torque
Solving Method:
1. Replacement
2. Replacement or correction
3. Lifting mechanism should be replaced; Traveling mechanism can be repaired.

G. Wheel group failure and damage condition:

1. Wheel tread and wheel spoke fatigue crack
2. The driving wheel tread wear unevenly
3. Wheel tread wear volume is amount to 15% of the thickness of the rim
4. Wheel rim wear volume is amount to 50% of the original thickness
The causes and consequences:
1. Wheel damage
2. Wheel gnawing rail, vibration and tilting operation
3. Wheel damage
4. Easily derail
Solving Method:
1. Replacement
2. Replacement
3. Replacement
4. Replacement

H. Lifting crane hydraulic brake failure and damage condition:

1. Pull rod fatigue crack
2. Spring fatigue crack
3. The spindle shaft wear volume is amount to 3%~5% of the nominal diameter
4. The brake wheel wear is amount to 1 ~ 2 mm or 40% ~ 50% of original flange thickness.
5. The brake shoe friction plate wear is amount to 2 mm
The causes and consequences:
1. Brake failed
2. Brake failed
3. Brake can’t be hold
4. Heavy down and slipping
5. Brake failed
Solving Method:
1. Replacement
2. Replacement
3. Replacement
4. Turning again heat treatment
5. Replace the friction plate
I. Coupling failure and damage condition:
1. The coupling crack
2. The bolt and the pin shaft hole wear
3. The gear of tooth shaped coupling gear wear or break
4. The key groove crushing and deformation
5. Pin shaft and rubber ring wear
The causes and consequences:
1. The coupling damage
2. The heavy fall
3. Lack of lubrication, hard work, playing the anti-direction
4. Off key and can’t transfer torque
5. Braking produce strong impact and vibration.
Solving Method:
1. Replacement.
2. The hoisting mechanism should be replaced with new parts, and the traveling mechanism expand hole after welding.
3. For the hoisting mechanism, when tooth wear is amount to 15% of the original thickness, it shall be replaced. For the traveling mechanism, when tooth wear is amount to 30% of the original thickness, it shall be replaced.
4. The hoisting mechanism should be replaced, and the traveling mechanism should be repaired.
5. Replace worn parts