The main reasons and analysis for the manual hoist running on the rail are as follows:

1、 Wheel installation and manufacturing issues

Installation deviation:

Horizontal deviation: When installing the wheels, the horizontal deviation is too large (not more than 1/1000 according to regulations), which causes the wheels to travel out of sync and causes compression friction between the wheel rim and the side of the track.

Vertical deviation: The wheel end face line forms an excessive angle with the plumb line (the vertical deviation should not exceed 1/400), causing the wheel to tilt and exacerbating rail gnawing.

Diagonal Unequal: Unequal diagonal wheelbase or poor straightness of two wheels on the same track can also cause rail gnawing.

Manufacturing error:

Diameter difference: The diameter difference of the driving wheels on the same bridge frame is too large, resulting in uneven walking distance per rotation and tilting of the vehicle body, causing rail gnawing.

Assembly tightness: The degree of tightness of the wheel assembly is inconsistent, resulting in different resistances, asynchronous driving machines, and rail gnawing caused by the tilting of the vehicle body.

2、 Track laying and maintenance issues

Laying deviation:

Uneven elevation: The relative elevation deviation between the two tracks is too large, causing lateral movement of the crane during operation, resulting in rail gnawing.

Horizontal bending: The horizontal bending of the track is too large, exceeding the span tolerance, causing friction between the wheel rim and the side of the track.

Uneven joint: Two adjacent rail tops on the same side are not in the same horizontal plane. When the crane reaches the rail joint, the wheels move laterally, causing rail gnawing.

Improper maintenance:

Foreign object pollution: There are foreign objects such as oil, water, and frost on the surface of the track, causing the wheels to slip and the vehicle to tilt, resulting in rail gnawing.

Severe wear: The side of the track is severely worn, forming a stepped shape, exacerbating the phenomenon of rail gnawing.

Loose fixation: Loose or broken track fixing bolts can cause deformation or displacement of the track, affecting the normal operation of the wheels.

3、 Bridge and transmission system issues

Bridge deformation:

Structural deformation: The deformation of the bridge frame causes the wheels to tilt and the crane span to change, resulting in horizontal bending of the end beam and causing the wheels to deviate horizontally and vertically beyond the tolerance.

Unstable support: The unstable support structure of the bridge frame causes the crane to shake during operation, exacerbating rail gnawing.

Transmission system error:

Gear clearance: Unequal gear clearance in the transmission system of the large vehicle operating mechanism causes rail gnawing.

Motor speed: The two motors have inconsistent speeds, resulting in a significant difference in linear velocity between the left and right wheels, causing the vehicle to tilt and gnaw on the track.

Brake adjustment: The degree of tightness of brake adjustment varies, which affects the stability of crane operation and exacerbates rail gnawing.

4、 Operation and environmental factors

Improper operation:

Diagonal pulling and lifting: The crane operator pulls and lifts the crane diagonally, causing the vehicle body to tilt and the wheel rim to rub against the side of the track.

Positioning issue: During remote control operation, the operator did not promptly detect the change in the position of the electric hoist, and did not adjust the position of the crane and electric hoist in a timely manner, resulting in inclined pulling and hoisting.

Environmental factors:

Ground slope: The ground slope in the lifting area affects the force on the lifting rope of the crane, causing the vehicle body to tilt and gnaw on the track.

Space limitation: The user unit has built a slope with high outside and low inside the cargo loading and unloading area, which restricts the normal operation of the crane and exacerbates rail gnawing.

The main equipment produced by Hebei Makita: stage electric hoist, electric chian hoist, wire rope electric hoist，Hand chain hoist, lever hoist, pneumatic hoist and other lifting equipment