Tuesday, 28 October 2014

The Harm Of Rail Gnawing

During normal operation, there should be a certain gap between wheel flange and orbit of bridge crane, maximum clearance for the 30-40mm. But in exceptional circumstances, flange and rail side will be under the mutual extrusion and friction, which causes the occurrence of rail biting fault and then affect the safe operation of crane.

The harm of rail gnawing can be mainly in the following three aspects. The first is to reduce the service life of the wheel and rail. For the bridge crane with serious rail gnawing, the service life of the wheel is less than 1 year, or even only a few months, while the use time of track can be only 3-5 years, much shorter than that in the normal case.
The second is to increase the running resistance. According to the determination, the bridge crane with serious rail gnawing has much larger running resistance, which can reach 1.5-3.5 times bigger than the normal running resistance. And this may cause that the load of motor and transmission mechanism increase and even overload. Bridge crane with very serious rail gnawing may has the problem that wheel rim has deformation by extrusion, which may cause a derailment accident.
The third is to do an adverse effect on the building structure. Crane with rail gnawing can easily produce lateral load, which will lead to lateral displacement of rail and looseness of the rail fixing bolt. In addition, the lateral force to the roof truss by rail can seriously affect the tray and plant stress conditions, making the roof slab bridge local loosening or fracture.

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