The Problem Analysis on Rail Looseness of Overhead Crane

We often meet the rail looseness problem in overhead cranes' inspection process and we will give a complete analysis on it:

The trolley wheels are out of sync:
1. The wheels don't stop at the same time as for the different braking time, which leads to the bridge's torsion. It may appear rail gnawing in serious conditions. At the same time, the wheels will have a friction coming from the girder, whose direction is vertical with trolley rail. It will make the rail be loose.
2. One side has braking on the wheels, but another side do not have braking or not so obvious.
Under this working condition, we will see obvious swing on the girder, when we start or stop the trolley. The end beam will swing back and forth on the side, that the braking is not so obvious. It will produce lateral thrust, when the wheel flange contacts with rail side. There will be a friction between wheel flange and rail, which will lead to rail looseness. At the same time, the end beam is served as bearing beam in the swing state. There will produce the friction on the rail, whose direction is parallel with the wheel base’s direction. The rails will appear to be loose, if we do not repair it.

Unstable crane structure:
The unstable crane structure will lead to the state of that the four wheels are not in the same surface level. There will be "three-leg" working condition. There will be a big "bump" on the trolley travelling and it may appear rail gnawing in serious conditions. The friction will lead to looseness of rail and pressing plate.

Wheel problems:
1. There is a lateral deviation on the wheels.
The end beam is horizontal curve, because the crane structure is deformed. It leads to wheel lateral deviation or the wheels have already been lateral deviation in installation.
2. There is a vertical deviation on the wheels.
There will be a vertical deviation variance on the wheels, because the crane structure is deformed. We should use the same group of wheels in installation. The wheels should be slant to the outside, which will reduce wheels' vertical deviation on the girder.
3. The diameters of the two driving wheels are different.
The speed is different on the left and right, when crane is working.
4. The front and back wheels are not on the same line in travelling.
The front and back wheels could not travel on the same line, because there is excessive deviation in span or diagonal caused by deformed crane structure.