Misalignment of Steel Wire Rope on Tower Crane Drum

 

The hoisting mechanism of the tower crane lifts materials by winding and releasing the wire rope through the drum, and the use of folded wire drum can improve the arrangement of multi-layer wire rope on the drum and prolong the service life of the wire rope. However, if the drum is not set up properly or for other reasons, the problem of untidy arrangement may still occur.

 

Reasons of drum wire rope arrangement is not neat 

 

Rope deflection angle is too large

The centre line between the flanges on both sides of the drum must be aligned with the fixed pulley. Under this premise, the angle between the wire rope from the drum to the first fixed pulley (i.e., the wire rope deflection angle) should be between 0.5 ° ~ 1.5 °, if the drum is 20m away from the first fixed pulley, the distance between the wire rope on the outer side of the drum and the middle of the drum should be no more than 520mm, i.e., the distance between the flanges of the two sides of the drum should be no more than 1040mm. If the wire rope deflection angle is too large, it will result in the rope in theIf the offset angle of the wire rope is too large, it will cause the wire rope to be disorderly arranged on the drum.

 

Insufficient pre-tensioning of wire rope

Drum multi-layer winding of wire rope, the first layer of wire rope arrangement must have enough preload, only the first layer of tight arrangement, the rest of the layers of wire rope can be arranged neatly.If the first layer of wire rope arrangement when the unloaded winding, will cause its preload is not enough, in the second layer of wire rope extrusion, very easy to lead to the wire rope local bulging and crushing, thereby damaging the wire rope.drum arrangement of the pre-tensioning force of the wire rope should be about 10% of its rated load.

 

Deviations in drum processing

If the drum itself has deviation, especially the drum side flange of the wire rope climbing platform and the wire rope layer transition with defects, will cause the wire rope in the arrangement of the rope and climbing rope problems, thus causing the upper layer of wire rope arrangement is not neat.

 

Solution

Drum wire rope arrangement is not neat in the 3 reasons, the first 2 are relatively easy to deal with, the following mainly for the more difficult to deal with the phenomenon of rope trapping or climbing rope in-depth analysis, in order to completely solve the problem of wire rope arrangement is not neat.

 

Climbing platform

Coiling multi-layer wire rope drum, the wire rope needs to climb from the lower layer to the upper layer. Before climbing, the lower layer of wire rope arrangement is neat, directly affecting the normal arrangement of the upper layer of wire rope. According to the actual use of the situation, to do the wire rope climbing normal key is the wire rope climbing platform. Climbing platform dimensions must be well coordinated with the winding of the wire rope to ensure that the multi-layer wire rope is neatly arranged.

 

According to the different diameter of the wire rope, the design size of its climbing platform is also different, and should be trimmed according to the actual situation. With the increase in the use of wire rope time, its diameter will be reduced, the wire rope and climbing platform will produce changes in the coordination of the wire rope winding is easily caused by misalignment. This is because when heavy load under the action of preload, the upper layer of wire rope will squeeze into the lower layer of wire rope, resulting in increased wear and tear of the wire rope. If the diameter of the wire rope becomes thin, it should be replaced with a new wire rope of the same specification.

 

Drum flange spacing is inaccurate

The wire rope is not neatly arranged and is directly related to the error in the inner width of the drum flange. Errors in the inner width of the drum flange can cause the wire rope to be misaligned.

 

According to the drum size and wire rope diameter, measure whether it meets the standard proportional relationship, and then according to the actual arrangement of the wire rope, to find out the causes of the arrangement deviation, and choose grinding or surfacing method to repair the drum flange.