KR20040024283A - Synthetic resin coated core for wire rope - Google Patents

Abstract

PURPOSE: A core coated with a synthetic resin for a wire rope is characterized by binding fiber core, increasing shape stability, preventing damage of the core and improving durability and fatigue resistance of the wire rope. CONSTITUTION: The core of the wire rope is obtained by the steps of: stranding first many fiber yarns(31A1) to prepare yarn fiber group(31A); stranding second the many yarn fiber groups(31A) to prepare fiber strand unit(31); stranding the many strand units(31) to prepare the core; and then coating circumference of the core with a synthetic resin coating layer(32). The synthetic resin coating layer(32) having 2-4mm of thickness is selected from polypropylene, PVC and polyethylene.

Description

Synthetic resin coated core for wire rope}

The present invention relates to a synthetic resin coating core (core, 芯, 芯 綱, 中芯) for the wire rope, and more particularly to the wire rope fiber core made by twisting natural or synthetic fiber yarn directly affecting the life of the wire rope The outer peripheral surface is coated with a synthetic resin such as polypropylene, PVC or polyethylene, and relates to a synthetic resin coating core for wire rope, which can significantly extend the life of the wire rope.

Wire ropes are widely used in various mechanical devices, industrial facilities, mines, etc., as shown in FIG. 1, a plurality of strands are formed around the core 11 that maintains the shape of the wire rope and serves as a central axis. The structures 12 are twisted in various forms such as a single layer or a double layer. In this case, each unit strand 12 has a structure in which a plurality of element wires 12B are stranded at a predetermined pitch on the outer circumferential surface of the core wire 12A.

The external load applied to the wire rope configured as described above may be in various forms such as bending, tension, and torsion, but the most important and basic axial tensile load of the wire rope is given as follows.

When an axial load is applied to the wire rope, the load is decomposed and acts as shown in FIG. That is, the axial load 21 applied to the outer layer strands is decomposed into a force 22 in the direction perpendicular to the longitudinal direction of the outer layer strands and a force 23 in the strand longitudinal direction.

Thus, the force 22 perpendicular to the strand length direction, i.e., perpendicular to the inter-strand interface reduces the duct 24 and contributes to the magnitude of the frictional force generated at the interface between the strands. The force 23 acting in the direction acts in the direction of decreasing the rotational curvature of the strand, as in the case of spring extension, which means that it acts as a compressive force towards the core.

That is, the force 22 perpendicular to the interface between the strands reduces the length 24 to match the longitudinal direction of the strands with the axial direction, and the rotation moment generated at this time also exerts a compressive force toward the center, thereby increasing the strand length. It is synergistic with the compressive force in the direction.

Therefore, the core of the wire rope is likely to collapse the form due to the compressive force of the outer strands, the core must not only have the durability to maintain the initial basic structure in spite of long-term use, but also to the external environment In order to maintain the corrosion resistance of the outer layer strands, it must have an excellent content capacity to continuously supply the rust preventive agent such as grease to the outer layer strands.

Cores that play such an important role in the performance of the wire rope include fiber cores and steel cores. The fiber cores are artificial fiber (synthetic fiber) cores and natural fiber cores, and the cores are independent strand cores (IWSC, Independent Wire Strand Core) and Independent Wire Rope Core (IWRC).

The fiber core is a source of grease to maintain the shape of the wire rope and to prevent the wear and corrosion of the wire rope.In addition to the steel core, the fiber core provides greater flexibility to the wire rope, resists shock and vibration, and is light in weight. Plays an important role in extending life.

The natural fiber core, one of the fiber cores, has a good absorption rate and excellent flexibility when grease is absorbed and enables continuous supply of grease to the outer layer strands, while under severe use conditions, it is easily deformed by the pressure of the outer layer strands. It is difficult to maintain the shape of the wire rope.

In addition, the artificial fiber core has a higher rigidity than the natural fiber core, which is better in terms of maintaining the shape of the wire rope due to its ability to withstand the pressure of the outer layer strands for long time use, but the outer layer strands have lower grease absorption rate than the natural fiber cores. Its contribution to rust resistance and lubricity is small, and its rigidity is significantly lower than that of steel core.

On the other hand, another core of the core has a characteristic that withstands high external pressure well, there is an advantage of excellent shape retention ability of the wire rope and increase the cutting load of the rope, therefore, the wire rope is used as a wire rope Used to increase cutting load without changing diameter, to reduce elongation of wire rope, or to prevent form damage due to side pressure applied to wire rope, and to use at high temperature do.

However, an independent strand shim wire rope, which is a kind of steel core, has extremely low flexibility and is rarely used for the same color, and is used only for coloring in a special case. The rope is more flexible than the independent strand seam wire rope and is used to secure proper tensile force as described above, but has a disadvantage in that the grease and flexibility between the strands are lowered and the fatigue resistance is lowered because the grease impregnation rate is lower than that of the fiber core.

Therefore, the wire rope used in container unloading equipment, which is used in a state such as a harbor and exposed to the outside and has to be excellent in corrosion resistance and needs flexibility to endure repeated bending movements, is light in weight. Fiber core wire rope with good flexibility and good grease absorption rate for corrosion resistance is generally employed, but the wire rope using the fiber core has a short life due to the above-described disadvantages.

The present invention has been devised to solve the problem of short life of the conventional wire rope having a fiber core, while maintaining the characteristics of the fiber core with good grease absorption rate, high shape stability against external load can significantly extend the life of the wire rope. It is an object of the present invention to provide a core for a wire rope using a fibrous core.

1 is a perspective view of a conventional wire rope.

2 is a tensile load action diagram given to a wire rope.

Figure 3 is a cross-sectional view of one embodiment synthetic resin coating core of the present invention.

Figure 4 is a cross-sectional view of a wire rope using an embodiment of the present invention core.

((Explanation of symbols for main part of drawing))

3,11. Core 12. Outer Layer Strand

21.External load

22. Component force perpendicular to the interface between the strands

23. Component force in the longitudinal direction of the strand

24. Soft wire 31. Fibrous unit strand

32. Synthetic resin coating layer 41. Outer strand

The above object of the present invention is achieved by a synthetic resin coating layer coated on the outer peripheral surface of the fiber core.

The synthetic resin coating core for the wire rope of the present invention is coated with a synthetic resin on the outer circumferential surface of the fiber core, and the synthetic resin coating layer stabilizes the shape of the fiber core by preventing the outer layer strands from penetrating into the fiber core along the weakness of the outer circumferential surface of the fiber core. Play a role.

The fiber core constituting the synthetic resin coating core for the wire rope of the present invention is a yarn twisted dozens of natural fiber yarns such as Manila hemp, Sisal hemp or synthetic resin yarns such as polypropylene and polyethylene. ) The fiber ends are formed, and the yarn fiber ends are twisted into tens of yarns to form fibrous unit strands, followed by stranding the fibrous unit strands, and in this case, three unit strands are usually stranded. Although a fiber core is comprised, the number of the unit strands on the said fiber phase can be adjusted according to a use.

As described above, by coating the outer circumferential surface of the fiber core made through a three-step twisting step of the fiber yarn → yarn fiber end → unit strand → fiber core, a synthetic resin coating core for wire rope is made by coating a synthetic resin such as polypropylene, FIVEC or polyethylene ,

That is, in the synthetic resin coating core of the present invention, the fiber core is protected by the synthetic resin coating layer, thereby preventing the outer layer strands from penetrating into the fiber core along the weak parts of the fiber core, that is, the contact portions of the fibrous unit strands, thereby improving the shape stability of the core. At this time, the thickness of the coating layer is most preferably in the range of 2 ~ 4mm.

Limiting the thickness of the coating layer as described above, if the thickness is less than 2mm, the binding strength of the coating layer to the fiber core is too small, the effect is insignificant, if the thickness exceeds 4mm, the form stability of the fiber core increases but the coating layer This is because the flexibility of the wire rope can be lowered and the durability of the wire rope can be lowered.

Details of the effects and the resulting effects, including the object and technical configuration of the present invention will be clearly understood by the following description with reference to the drawings showing a preferred embodiment of the present invention.

Figure 3 is a cross-sectional view of the synthetic resin coating core for an embodiment of the present invention wire rope, Figure 4 is a cross-sectional view of the wire rope using a synthetic resin coating core for the present invention one embodiment wire rope.

As shown in the figure, the synthetic resin coating core 3 of the present invention is secondarily stranded a plurality of yarn fiber ends 31A that are primarily stranded with a plurality of fiber yarns 31A1 to form a fibrous unit strand 31, The synthetic resin coating layer 32 is coated on the outer circumferential surface of the fiber core in which a plurality of unit strands 31 are stranded.

Then, the wire rope is made by twisting a plurality of outer layer strands 41 on the outer circumferential surface of the synthetic resin coating layer 32.

At this time, grease is filled in all the spaces formed inside the wire rope, including the space V formed between the fibrous strands 31 and the outer layer strands 41 and the coating layer 32.

In the synthetic resin coating core of the present invention configured as described above, the fiber by friction with the steel wires because the oil-based strands 31 and the outer layer strands 41, which are generally composed of a plurality of steel wires, do not contact each other. While the core is prevented from burning, the phenomenon that the outer layer strands penetrate between the unit strands is suppressed.

In addition, unlike conventional wire rope in which fiber yarns of fiber cores are broken or damaged by using for a long time, when the wire rope manufactured by using the synthetic resin coating core of the present invention is used for a long time, the synthetic resin coating layer constituting the present invention is made of fiber core. A plurality of gaps preferentially occur along the grain, and grease that has been incorporated into the fiber core is discharged through these gaps, thereby reducing the frictional force between the outer strand and the coating layer and the fiber core, thus delaying the point of damage of the fiber core and thus the wire rope. Its life is extended.

That is, the friction behavior of the wire rope manufactured using the synthetic resin coating core of the present invention to the external load can be divided into two stages, and the steps will be described in detail as follows.

Initial friction that occurs in the wire rope using the core of the present invention, the grease is interposed between the inner layer outer surface and the outer surface of the coating layer and between the inner layer surface and the outer core surface of the coating layer, respectively, the coating layer binds the fiber core to maintain its shape At the same time, with the grease attached to the inner and outer circumferential surfaces, they themselves serve as a lubricating layer between the outer strand and the fiber core.

Further, fine cracking occurs in the coating layer along the fiber core and the outer layer strands due to repeated friction and compressive force as the wire rope is used for a long time, and the grease contained in the fiber core is supplied to the outer layer strand side through the gap. In spite of cracking of the coating layer, the frictional resistance between the outer strand and the fiber core is reduced.

As described above, the synthetic resin coating core for wire rope of the present invention not only improves the shape stability by tying the fiber core, but also improves the durability of the wire rope by suppressing damage of the fiber core by friction with outer layer strands. Finally, there is an advantage of significantly improving the fatigue resistance of the wire rope.

Claims (3)

In the core of a wire rope in which a plurality of outer layer strands are stranded on the outer circumferential surface of the core, a plurality of yarn fiber ends 31A formed by first stranding a plurality of fiber yarns 31A1 are secondarily stranded to form a fibrous unit strand 31. And a synthetic resin coating layer (32) coated on an outer circumferential surface of a fiber core twisted with a plurality of unit strands (31). The synthetic resin coating core for wire rope according to claim 1, wherein the fiber yarn (31A1) is one of Manila hemp, Sisal hemp, polypropylene yarn, and polyethylene yarn. The synthetic resin coating core for wire rope according to claim 1, wherein the synthetic resin coating layer (32) is one of polypropylene, FBC, and polyethylene and has a thickness of 2 to 4 mm.