Selection principle of wire rope for electric hoist
The wire rope is a very common part of the hoisting machinery. The electric hoist is used as a kind of lifting equipment, and of course the wire rope is indispensable. Wire ropes are generally woven from high-strength steel wire. In order to be safe at work, we must pay attention to the principle of selection of wire ropes.
China's wire rope according to the core material is generally divided into organic (hemp core and cotton core), asbestos core or metal core three kinds, the rope usually has no filler or lubricant inside. The wire rope can be divided into a straight rope and a cross rope according to the mutual direction of the wire wound into a strand and the strand is wound into a rope, and is divided into left and right directions and left and right sides according to the twist direction of the strand; the imported wire rope Generally, the cross-cored rope is used as a standard rope, and the rotation direction of the steel cord is defined to be the same as the spiral direction of the outer-strand spiral relative to the longitudinal axis of the steel cord, and is divided into left-handed and right-handed. Correspondingly, the direction of rotation of the strands is also defined, that is, the direction of the spiral of the outer strands constituting the strand is the direction of rotation of each strand based on the vertical axis of the strand. When the ordinary steel wire rope is used in a single root, it has a phenomenon of rotating the wire rope in the opposite direction. When used in the pulley block, the wire rope is twisted due to the rotation of the wire rope, which is commonly called twisting. Compared to ordinary wire ropes, the current non-rotating wire ropes have begun to be widely used. The so-called non-rotating wire rope is based on the principle that the torsion moment of the rope and the strand are opposite in direction and equal in size: the inlet does not rotate the wire rope is different, the principle is that the rotation direction of the rope core is opposite to the rotation direction of the rope itself, when When the force is applied, the torque generated by the rope core is equal to the torque generated by the outer strand, and the direction is opposite.
The choice of wire rope is related to the service life of the rope and the structural deformation, fracture and accidental failure of the rope. Therefore, the following principles must be followed. If there is no guide weight lifting or multiple unguided weights at a large height. When lifting, select the non-rotating wire rope; if there is a guide weight lifting or a guide weight lifting multiple times at a small height (or left-handed and right-handed rope pairing, you can use ordinary wire rope.
After the wire rope has been used for a long time, it will wear out and cause breakage. Therefore, it is necessary to pay attention to selecting a steel wire rope with high wear resistance and crush resistance when selecting. In addition to the selection of wear-resistant wire ropes, it is also necessary to pay attention to the details of its use, as well as maintenance inspections, etc., to ensure that its safety performance is good before it can be put into use.
