JP3209610B2 - Non-rotating wire rope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-rotating wire rope used for cranes, mobile cranes, and the like.

[0002]

2. Description of the Related Art When an object is lifted by a crane or a mobile crane, if the lifting rope is a normal six-strand rope as shown in FIG. To rotate. This rotating force is generally called a torque force, and a coefficient proportional to the tension is called a torque coefficient.

When an object is lifted using one six-strand rope, the object is rotated by the torque force, and the rope is further twisted, resulting in a dangerous state. When an object is hoisted using a plurality of six-strand ropes, the ropes tend to be entangled with each other, making it difficult to wind up.

In order to prevent such inconvenience, ropes for lifting cranes and mobile cranes include:
Non-rotating wire ropes having a small torque coefficient (small torque force) are used.

[0005] Typical non-rotating wire ropes include:
There are three types, a three-strand type monorope as shown in FIG. 6B, a four-strand type monorope as shown in FIG. 6C, and a naflex rope as shown in FIG. 6D. Table 1 below shows the torque coefficients of these ropes in comparison with the torque coefficients of the six-strand ropes.

[0006]

[Table 1]

When these three types of non-rotating wire ropes are compared, the three-strand type monorope and the four-strand type monorope have large irregularities as apparent from the cross-sectional view shown in FIG. But,
In contrast, the surface of the Naflex rope is smooth.

[0008] The hoisting and unwinding of the rope by the crane and the mobile crane are performed by winding up and rewinding on a winding drum. In a high-lift crane or a mobile crane with a long rope, FIG.
As shown in (1), a large number of sections of the rope R are wound around the winding drum D, and the number of winding steps of the rope R increases.

A large pressure is applied to the rope R wound on the winding drum D from up, down, left and right. However, when the number of winding steps increases, the upper rope drops due to the deformation of the rope R between adjacent adjacent lower ropes. It becomes impossible to withdraw. The mono-rope type non-rotating rope has a drawback that the fiber core is contained therein, so that it is relatively easily deformed and easily falls between adjacent ropes.

Furthermore, when the rope is unwound or unwound from the winding drum, the surfaces of the ropes that are adjacent to each other rub against each other, but the monorope type has large irregularities on the surface. The surface wires are easily broken due to the rubbing, which makes the rope unsuitable for use as a high-lift rope.

On the other hand, in the Naflex rope, the wires are densely packed into the rope and the surface is also smooth, so that the rope may drop due to deformation,
It is suitable for use as a non-rotating wire rope having a high lift without breaking due to strong rubbing.

The naflex rope is a multilayer strand rope in which an inner layer strand is disposed inside an upper layer strand, and the direction of the upper layer strand and the direction of the inner layer strand are opposite to each other. Due to the difference in direction between the upper layer strand and the inner layer strand, the torque force is canceled and non-rotational characteristics are generated.

For example, in the case of the tough naflex rope TS (19) + 39 × 7 shown in FIG. 6 (d), assuming that the specification of this rope is Z, the 21 strands of the inner layer are twisted by S. The eighteen strands of the upper layer arranged on the inner layer are twisted together.

[0014]

However, in such a non-rotating wire rope using a naflex rope, since the direction of the upper strand is opposite to that of the inner strand, when a load is applied, The strands of one layer are unraveled and the strands of the other layer are more clogged, but due to long-term use or fluctuations in load, the strands move and concentrate in some places as shown in FIG. A cage-like shape collapse may occur, and the cage-like shape collapse makes the rope unusable. This shape collapse
It also occurs due to inadequate handling methods at the time of rope preparation.
A disadvantage of the non-rotatable wire rope due to the naflex rope is that such a cage-like shape collapse occurs.

The present invention has been made in view of such a point, and it is an object of the present invention to prevent a cage-shaped shape from being generated and to be used stably for a long period of time. An object of the present invention is to provide a non-rotating wire rope by a flex rope.

[0016]

According to the present invention, in order to achieve the above object, an inner layer strand is disposed inside an upper layer strand, and the direction of the upper layer strand and the direction of the inner layer strand are determined. Is a non-rotating wire rope composed of naflex ropes whose directions are opposite to each other, the value obtained by dividing the length of the upper layer strand by the rope diameter is defined as a pitch multiple (NR). When the width of the gap is defined as spacing, and the sum of the spacing between each is divided by the diameter (layer core diameter) of the circle passing through the center of each of the upper layers, and the value is defined as the spacing ratio (%). The pitch multiple (NR) is set to 7.0 or less and the spacing ratio is set to 1.0% or more.

[0017]

[Function] The cause of the cage-like shape collapse is that the strands move and are clogged and concentrated in some places. Therefore, if the further movement is suppressed, the cage-like shape collapse will occur. This can be prevented.

As in the present invention, the pitch multiple (NR) is 7.0
If the spacing ratio is less than 1.0%, the length of the strand becomes shorter and the nature of the spring occurs. The original state is restored, and since the spacing S between the adjacent strands b of the upper layer is large, the spacing S acts as a margin for further movement, and a margin is provided for further movement, and It is possible to avoid being clogged with concentration in some places, thereby suppressing the occurrence of the cage-shaped shape collapse.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, 21 strands a constituting the inner layer are twisted by S, and the strand a
The figure shows a Naflex rope R formed by twisting 18 strands b constituting an outer layer with Z.

Here, the longer length of the rope R is represented by the longer length of the eighteen strands b in the upper layer, and a value obtained by dividing this longer length by the diameter of the rope R is a pitch multiple ( NR). Pitch multiple (NR) = More length (mm) / Rope diameter (m
m)

As shown in FIG. 5, the diameter of a circle passing through the center of each upper layer strand b is defined as a layer core diameter D, and the width of a gap between adjacent upper strands b is defined as a spacing S. The value obtained by dividing the total sum of the spacings S between the layers by the layer core diameter D is defined as a spacing ratio (%).

As a prototype, a pitch multiple (NR)
16 types of ropes R were produced by combining four levels of 7.5, 7.0, 6.5, and 6.0 with four levels of spacing rates of 0.50, 0.75, 1.00, and 1.25.

FIG. 3 shows these 16 types of ropes R.
S bending test was performed using a wire rope bending fatigue tester as shown in FIG. In this S bending test, an auxiliary rope R 'is connected to both ends of the rope R by a joint 1 to form an endless shape, the rope R is wrapped around a pair of nylon sheaves 2, and the auxiliary rope R' is connected to the driving sheave 3 and the tension. A constant tension (5tf; safety factor 12)
Under the condition that the rope R was repeatedly passed through the nylon sheave 2. Then, a pair of nylon sheaves 2 are arranged so that the central axes thereof are shifted by an angle of 4 ° as shown in FIG. 4 to move the twist of the rope R. Was generated, and the number of repetitions until the shape collapse occurred was measured. The test results are shown in Table 2 below.

[0025]

[Table 2] The circles in the table indicate that the cage-shaped shape collapse did not occur even when the number of repetitions reached 1,000. The repetition was stopped 1000 times.

As is apparent from Table 2, it was found that the cage R did not collapse in the rope R having a pitch multiple (NR) of 7.0 or less and a spacing ratio of 1.0% or more.

This is because when the pitch multiple (NR) is 7.0 or less and the spacing rate is 1.0% or more, the length of the strand b becomes shorter and the nature of the spring is generated, which causes the Even if it moves temporarily, it is immediately restored to the original state by the elastic force of the spring, and since the spacing S between the adjacent strands b of the upper layer is large,
The spacing S acts as a movement margin during the further movement, so that it is possible to avoid a situation where the movement has a margin and the more part is concentrated and clogged in some places, thereby preventing the cage from deforming. The occurrence is suppressed.

The present invention is also applicable to naflex ropes such as a super naflex rope (35 × 7) shown in FIG. 2 (a) and a tough super naflex rope (T35 × 7) shown in FIG. 2 (b). By applying the same method, it is possible to prevent the cage from breaking down.

[0029]

As described above, according to the present invention, it is possible to prevent the occurrence of a cage-like shape collapse and to use it stably for a long time as a non-rotating wire rope of a crane, a mobile crane and the like. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a non-rotating wire rope according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view of a non-rotating wire rope according to another embodiment of the present invention.

FIG. 3 is a front view for explaining the S-bending fatigue test method of the wire rope.

FIG. 4 is a plan view seen from the direction of arrow A in FIG. 3;

FIG. 5 is a plan view showing spacing of upper strands in a naflex rope.

FIG. 6 is a sectional view showing a sectional structure of various wire ropes.

FIG. 7 is a sectional view showing a state in which a rope is wound around a winding drum.

FIG. 8 is a perspective view showing a state in which a cage-shaped shape collapse has occurred in the rope.

[Explanation of symbols]

 R: Naflex rope a: Inner layer strand b: Upper layer strand

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-65587 (JP, A) JP-A-53-119355 (JP, A) JP-A-63-12785 (JP, A) JP-A-62 21888 (JP, A) Japanese Utility Model Sho 58-180299 (JP, U) Patent 2916520 (JP, B2) Japanese Patent Publication 51-18537 (JP, B1) Japanese Patent Publication 48-31943 (JP, B1) (58) Survey Field (Int.Cl. ⁷ , DB name) D07B 1/00-9/00

Claims (1)

(57) [Claims] 1. A non-rotating wire rope comprising a naflex rope in which an inner layer strand is disposed inside an upper layer strand, and the direction of the upper layer strand and the direction of the inner layer strand are opposite to each other. The value obtained by dividing the length of the upper layer strand by the rope diameter is defined as a pitch multiple (NR), the width of the gap between adjacent adjacent strands of the upper layer is defined as the spacing, and the sum of the spacing between the respective strands Divided by the diameter of the circle (layer core diameter) passing through the center of each strand in the upper layer, the spacing rate (%)
When the pitch multiple (NR) is 7.0 or less,
A non-rotating wire rope, wherein the spacing rate is set to 1.0% or more.