2013年8月25日星期日

Three rope frayed Analysis

The hoist rope can be said that the most frequently used accessories, but also lifting the most widely used, but when the operation wire in contact with other objects, friction. In the mechanical, physical and chemical action, wire rope wear and other issues will continue to surface, a serious impact on the  lift hoist  and the whole machinery of operation and efficiency, the following is your analysis of the three main situations rope wear:
1, deformation wear
Due to vibration, collision damage caused by the rope hit the surface, called deformation wear, abrasion is a local phenomenon. If the surface of the wire rope drum impact by other objects, wire rope electric hoist lifting wrapped around each other to fight, or due to deflection pulley and roll center phenomena arising bite rope, wire rope will cause deformation wear. This deformation wear and deformation due to local press, the wire cross-section extending to the sides at the extrusion into a fin-shaped.chain block From outward appearances, wire width expansion, although much reduced wire cross-sectional area, but the local press at the steel surface material hardened, easily broken wire.
2, internal wear
In use, the rope pulley rolls or after exposure to the entire load of the pressure in the side of the rope, the plurality of thin wires can not be exactly the same radius of curvature. Same time as the rope bends, wire rope, steel wire inside the root will generate force and produce another slip, then contact stress between stocks and shares increases, the share between adjacent wires produce local indentation furrow. When repeated cycles stretch bending, is generated in the deep recesses of stress concentration was broken, constitute internal wear. Usually thin wire rope surface pressure and the pressure proportional to the tension of the same case, since the pressure receiving area are different, the pressure per unit area is different. Under pressure from the surface wear of view, the use of line contact wire rope advantageous than using point contact, the use of surface contact wire rope line contact than using more favorable. In addition, the degree of bending wire rope, velocity, internal wear on the rope are affected. Obviously, the selection line contact or surface contact type of rope is an effective way to reduce internal wear.
3, the external wear
In the course of wire rope and the pulley groove outer periphery, drum set, a top hook surface wear caused by the contact part of the external wear. The external worn rope diameter becomes thinner,hoist and trolley the outer peripheral surface is polished fine steel.
External wear of the rope to bear the load of the wire cross-sectional area decreases, the rope breaking load is reduced accordingly.
Wear a single week than the whole week wear worse, hook group it should be possible to make a single week of the wire to wear uniform wear all week. Entire length of the wire should be as far as possible uniform wear. Such as cranes wire rope used for the first medium-term, generally extend rope life 30% to 40%.

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