The drum is subjected to the compressive action of the steel wire rope, as well as the bending and twisting action caused by the steel wire rope, and the compressive action plays the main role. There have been accidents where the drum has cracked and the steel wire rope has pressed it in, so if cracks are found in the drum, it should be scrapped. The drum shaft is subjected to bending and shear stress, and if cracks are found, they should be scrapped in time, otherwise there is a possibility of a broken shaft accident; the wear depth of the drum groove should not exceed 2mm when exceeding it can be re-grooved, but the drum wall thickness should not be less than 80% of the original wall thickness; there shall be no cracks above and below the wheel hub, and the connecting bolts on it shall be tightened.
The inspection and repair of steel wire rope running off the groove on the drum: When the relative angle between the steel wire rope and the groove is too large, the steel wire rope will wear the edge of the groove or jump out of the groove, causing serious wear to the steel wire rope. For a grooved drum, the allowable relative angle between the steel wire rope and the groove is 4-5°. When it exceeds 6°, the steel wire rope may jump out of the groove. The common reasons for this are usually too small a distance between the hook pulley group and the drum. In this case, appropriate adjustments can be made. It may also be due to the inclination of the hook pulley group relative to the safe position of the drum, or due to the inclined lifting of goods causing the steel wire rope to jump out of the groove.
In addition, when a new steel wire rope is replaced, if the twist (caused by winding on a wooden drum) of the steel wire rope has not been relaxed, it will also cause the steel wire rope to jump out of the groove, or even cause several strands of the pulley group to become entangled. To prevent this accident, the coiled steel wire rope can be hung up and gradually unwound and straightened, and the twist can be eliminated.
The selection of steel wire rope for cranes should consider the use environment and occasion, as well as the degree of workload. Generally, the steel wire rope for cranes should have good flexibility. The steel wire rope wrapped around the pulley and drum should be selected first with line contact steel wire rope. In an environment with acid, alkali, and other corrosion, zinc-plated steel wire rope should be used.
Steel wire ropes used in high-temperature environments should be selected with asbestos core and gold-plated core as a good choice. To make the lifting operation stable and not cause a twisting phenomenon, the general use of alternating twist (reverse twist) steel wire ropes. To ensure that the steel wire rope has a certain service life, the correct selection of the safety factor of the steel wire rope should be made according to the working level and purpose of the mechanism.
