JP7625375B2 - Cable Laid Rope - Google Patents

Description

The present invention relates to a cable laid rope.

Traditionally, wire ropes have been made from materials such as steel or stainless steel. Wire ropes are used in many fields due to their properties of being strong, flexible, and long. Depending on their application, wire ropes are divided into static ropes, which are used as structural members, and dynamic ropes, which are used for transport equipment, etc. A typical wire rope has a structure in which strands made of twisted wires are twisted around a rope core (made of steel, fiber, etc.).

There are two ways to twist a rope: normal twist, where the twist direction of the rope itself is different from that of the strands, and Lang twist, where the twist direction is the same. With normal twist ropes, the twist is less likely to return to its original shape, making them less likely to kink and easier to work with. On the other hand, Lang twist ropes tend to return to their original shape, but the twist of the wires is more gradual, making them more resistant to abrasion. Normally twisted ropes are used more commonly.

Even ordinary twisted wire ropes have the property of rotating in the direction in which the twist unwinds when a load is applied (rotating property). This means that in applications such as cranes, the load will rotate, and in the case of hoisting ropes, this can lead to tangling of the hook sheave. For this reason, non-rotating ropes are used, but due to their structure, non-rotating ropes are hard and difficult to handle. Non-rotating ropes are disclosed, for example, in Patent Documents 1 to 4.

In response to this, a cable laid rope, which is a flexible wire rope, is known, as disclosed in Patent Document 5. The cable laid rope disclosed in Patent Document 5 has a 7 x (IWRC6 x WS (36)) structure and is made up of 1,855 individual wires, making it a flexible wire rope.

Japanese Patent Application Publication No. 6-287876 JP 2000-160488 A JP 2001-140177 A JP 2001-192989 A Japanese Patent Application Publication No. 4-50388

However, although the cable laid rope disclosed in Patent Document 1 is used as a flexible wire rope, it cannot be expected to have any anti-rotation properties.

Therefore, the present invention was made in consideration of the above-mentioned conventional technology, and its purpose is to provide a cable laid rope that is both flexible and non-rotating.

In order to achieve the above-mentioned object, the present invention provides a cable laid rope in which three or four schenkels, each of which is made of a plurality of strands twisted together, are twisted together, the twisting direction of the schenkels is opposite to the twisting direction of the strands, the twisting pitch of the schenkels is 7 to 11 times the rope diameter, adjacent schenkels are in contact with each other, each of the plurality of strands is made of a plurality of wires twisted together, and the twisting direction of the strands is the same as the twisting direction of the wires .

The cable laid rope according to the present invention can have non-rotating properties while ensuring the flexibility of a wire rope. That is, since the cable laid rope is made of three or four schenkels twisted together, when a tensile load is applied to the cable laid rope, such as when a load is hung, the force that causes the schenkels constituting the outermost layer to unravel can be weakened. Moreover, since the twisting direction of the schenkels is opposite to the twisting direction of the strands, and the twisting pitch of the schenkels is 7 times or more and 11 times or less than the rope diameter, the force that causes the schenkels to unravel can be easily balanced with the force that causes the strands to tighten. As a result, a rope with non-rotating properties can be obtained. Furthermore, since the schenkels are twisted together, which are made of twisted strands, the flexibility can be improved compared to a non-rotating rope with a structure that does not have schenkels. Therefore, even if the number of schenkels is three or four, the flexibility of a cable laid rope can be ensured.

In addition, since the strands are twisted in the same direction as the wires, when a tensile load is applied to the cable laid rope, such as when the cable laid rope is used to suspend a load, the force that causes the schenkels in the outermost layer to loosen acts as a force that causes the strands to tighten more and a force that causes the wires to tighten more. This makes it easier to balance the forces that cause the rope to loosen and the forces that cause the rope to tighten more. As a result, the rope is less likely to rotate.
The cable laid rope may have a flexibility of 1570 to 2400.

As described above, the present invention makes it possible to provide cable laid ropes with flexibility and anti-rotation properties.

FIG. 1 is a diagram for explaining the configuration of a 3×(7×7) cable laid rope. FIG. 1 is a diagram for explaining the configuration of a 4×(7×7) cable laid rope. FIG. 1 is a diagram for explaining the configuration of a cable laid rope having a 3×(IWRC6×S(19)) configuration. FIG. 1 is a diagram for explaining the configuration of a cable laid rope having a 4×(IWRC6×S(19)) configuration. FIG. 1 is a diagram for explaining the configuration of a cable laid rope having a 3×(IWRC6×WS(31)) configuration. FIG. 1 is a diagram for explaining the configuration of a cable laid rope having a 4×(IWRC6×WS(31)) configuration.

The following describes in detail the embodiment of the present invention with reference to the drawings.

The cable laid rope 10 according to this embodiment is a cable laid rope with a 3x (7x7) configuration, as shown in Figure 1. Specifically, the cable laid rope 10 is configured by twisting together three schenkels 20, and each schenkel 20 is configured by twisting together seven strands 30. Each strand 30 is configured by twisting together seven wires 40. Note that, as shown in Figure 2, instead of three schenkels 20, the cable laid rope may have a 4x (7x7) configuration in which four schenkels 20 are twisted together.

To make this cable laid rope, first, seven steel wires 40 are twisted together to form a strand 30, and seven of these strands are twisted together to form a schenkel 20. The cable laid rope 10 can then be obtained by twisting three or four schenkels 20 together. After twisting the three or four schenkels 20 together, the diameter may be reduced using a swaging machine (not shown). This makes it possible to further reduce the layer core diameter (the diameter of an imaginary circle whose circumference passes through the centers of multiple schenkels 20).

A wire having a nominal diameter of 0.76 to 0.89 mm is used as the wire 40. The layer core diameter of the cable laid rope 10 is 7.7 mm to 8.5 mm (for example, about 8.1 mm). Since three or four schenkels 20 are used in this cable laid rope 10, the layer core diameter can be kept relatively small. This makes it possible to relatively reduce the rotational moment when the cable laid rope 10 is pulled, thereby reducing the rotational force of the cable laid rope 10 and improving its non-rotational properties.

The twist direction of the cable laid rope 10 (twist direction between the schenkels 20) is opposite to the twist direction of the schenkels 20 (twist direction between the strands 30). In other words, the cable laid rope 10 is a wire rope with normal twist. On the other hand, the twist direction of the schenkels 20 is the same as the twist direction of the strands 30 (twist direction between the wires 40). In other words, each schenkel 20 is Lang twisted. This increases the resistance of the strands 30 to the rotational force that tries to unravel the cable laid rope 10 (the rotational force that tries to unravel the schenkels 20). That is, the twist direction of the cable laid rope 10 is opposite to the twist direction of the schenkels 20, and the twist direction of the schenkels 20 is the same as the twist direction of the strands 30. Therefore, when the cable laid rope 10 tries to rotate in a direction to unravel, the strands 30 constituting each schenkel 20 and the wires 40 constituting each strand 30 rotate in a direction to tighten. Therefore, the anti-rotation property of the cable laid rope 10 is improved.

The twist pitch of the cable laid rope 10, i.e., the twist pitch between the schenkels 20 in the axial direction (the axial length of the rope 10 required for one schenkel 20 to make a 360-degree turn), is set to 7 to 11 times the diameter (rope diameter) of the cable laid rope 10. Here, the diameter of the cable laid rope 10 is defined by the diameter of the circumscribing circle of the cable laid rope 10. The twist length can be set within the range of 7 to 11 times according to the desired anti-rotation performance.

The structure of the schenkel 20 (number of wires and number of strands), the presence or absence of a rope core, etc. can be changed depending on the application. For example, when abrasion resistance or corrosion resistance is required, a configuration with a small number of wires can be adopted while keeping the diameter of the cable laid rope 10 at a specified diameter. On the other hand, when flexibility or bending fatigue resistance is required, a configuration with a large number of wires can be adopted while keeping the diameter of the cable laid rope 10 at a specified diameter.

The cable laid rope 10 can be configured by twisting together schenkels 20 having IWRC6 as shown in Figures 3 to 6. Specifically, the cable laid rope 10 shown in Figure 3 has a configuration of 3 x (IWRC6 x S (19)), and the cable laid rope 10 shown in Figure 4 has a configuration of 4 x (IWRC6 x S (19)). The cable laid rope 10 shown in Figure 5 has a configuration of 3 x (IWRC6 x WS (31)), and the cable laid rope 10 shown in Figure 6 has a configuration of 4 x (IWRC6 x WS (31)).

Here, we will explain an example of the cable laid rope 10.

As shown in Table 1, the cable laid ropes 10 of Examples 1 to 6 are all cable laid ropes 10 of 3×(7×7) configuration, and are configured by twisting together three schenkels 20. In Examples 1 and 4, the twist length ratio is 8, in Examples 2 and 5, the twist length ratio is 9, and in Examples 3 and 6, the twist length ratio is 10. Here, the twist length ratio means the ratio of the twist pitch of the cable laid rope 10 to the outer diameter (rope diameter) of the cable laid rope 10. In all of Examples 1 to 6, strands 40 with a nominal diameter of 0.76 to 0.89 mm are used. Note that none of Examples 1 to 6 is subjected to swaging.

In Examples 1 to 3, the twist direction is S×(Z×Z). That is, the rope 10, schenkel 20, and strand 30 are S-twisted, Z-twisted, and Z-twisted in that order. That is, the strand 30 is Z-twisted (seven wires 40 are twisted together in the Z direction), the schenkel 20 is Z-twisted (seven strands 30 are twisted together in the Z direction), and the cable laid rope 10 itself is S-twisted (three schenkels 20 are twisted together in the S direction). In contrast, in Examples 4 to 6, the twist direction is S×(Z×S), and they differ from Examples 1 to 3 in that the strands 30 are S-twisted, but are otherwise the same as Examples 1 to 3.

The cable laid rope of Comparative Example 1 is IWRC6x (IWRC6xS(19)) and has six schenkels twisted around the core of the rope. The twist direction of the cable laid rope of Comparative Example 1 is Zx (SxZ).

The flexibility was measured for the cable laid ropes 10 of Examples 1 to 3 and the cable laid rope of Comparative Example 1. The flexibility is an index showing the ease of bending of a rope, and can be obtained from the change in the amount of deflection when a 400 mm long rope is supported at both ends and the weight of a weight suspended at the center is increased. More specifically, the diameter of the cable laid rope 10 is d, the amount of change in the amount of deflection is Δy, the amount of change in load is ΔQ, and the flexibility is F, and the flexibility F was calculated from the following formula (1). For Δy/ΔQ, the slope of the approximation line in the region where the amount of change in deflection Δy changes linearly with the amount of change in load ΔQ is used.
F=4.96× ¹⁰⁴ × ^d4 /(400) ³ ×Δy/ΔQ...(1)

The rotation angle and rotation torque coefficient were measured for the cable laid ropes 10 of Examples 1 to 6 and the cable laid rope of Comparative Example 1. The rotation angle represents the rotation angle (°) in a span of 10 x d (d is the diameter of the rope) when a weight of about 20% of the actual breaking force is hung. However, for the cable laid rope of Comparative Example 1, a test was performed in which a weight of about 10% was hung. The load was reduced in Comparative Example 1 because a considerable amount of rotation was expected. Note that rotation in the direction in which the rope itself unravels (the direction in which the twist between the schenkels 20 is unwound) is considered to be a positive rotation, and rotation in the direction in which the rope itself tightens is considered to be a negative rotation. If the rotation angle is 40° or less, it can be said to have non-rotating properties.

The rotational torque coefficient represents the torque required for a 1m rope to return to its original position when a tensile load of approximately 20% of the actual breaking strength is applied to the rope, and is calculated using the following formula.

k={T/(W・d)}×10 ³ ...(2)
In addition, k is the rotation torque coefficient, W is the tension (N) acting on the rope, T is the torque generated in the rope by the tension W, and d is the rope diameter (mm). If it is 0.030 or less, it can be said to have non-rotation properties.

As shown in Table 1, the flexibility of the cable laid ropes 10 of Examples 1 to 3 is 1570 to 2400, which is lower than the flexibility of the cable laid rope of Comparative Example 1. However, compared to general wire ropes (References 1 to 3) that are not cable laid ropes and do not have schenkels, the flexibility of the cable laid ropes 10 of Examples 1 to 3 is much greater. Here, the configurations of the wire ropes of References 1 to 3 are 3 x F (40), 4 x F (40), and 6 x 37, respectively. Therefore, it can be seen that the cable laid ropes 10 of Examples 1 to 3 ensure the flexibility of a wire rope.

As shown in Table 2, the cable laid ropes 10 of Examples 1 to 6 are all within the range defined as non-rotating in terms of both rotation angle and rotation torque coefficient, so Examples 1 to 6 can be said to be non-rotating. In contrast, Comparative Example 1 does not meet the definition of non-rotating in terms of both rotation angle and rotation torque coefficient. From the above, all of Examples 1 to 6 can be non-rotating while maintaining the flexibility of a wire rope.

In addition, in Examples 1 to 3, the non-rotation property is enhanced more than in Examples 4 to 6. In Example 2, where the twist length ratio is 9 times, there is no rotation even when a tensile load is applied, and when the twist direction is S×(Z×Z), the non-rotation property is enhanced most when the twist length ratio is 9 times. With reference to Examples 4 to 6, where the twist direction is S×(Z×S), if the twist length ratio is increased in the case of S×(Z×S), the non-rotation property may be enhanced more, but if the twist length ratio exceeds 11 times, undulations are likely to occur and the schenkel 20 is likely to come undone. On the other hand, if the twist length ratio is less than 7 times, there is a possibility that the non-rotation property cannot be obtained. Therefore, the twist length ratio is preferably 7 times or more and 11 times or less, more preferably 7 times or more and 10 times or less, and may be 8 times or more and 10 times or less.

As described above, the cable laid rope 10 according to this embodiment can have non-rotating properties while maintaining the flexibility of a wire rope. That is, since the cable laid rope 10 is made by twisting three or four schenkels 20 together, when a tensile load is applied to the cable laid rope 10, such as when a load is hung, the force that the schenkels 20 constituting the outermost layer tend to unravel can be weakened. Moreover, since the twisting direction of the schenkels 20 is opposite to the twisting direction of the strands 30, and the twisting pitch of the schenkels 20 is 7 times or more and 11 times or less than the rope diameter, the force that the schenkels 20 tend to unravel can be easily balanced with the force that the strands 30 tend to tighten. As a result, a rope having non-rotating properties can be obtained. Furthermore, since the schenkels 20 are twisted together, the flexibility can be improved compared to a non-rotating rope having a structure without schenkels. Therefore, even if the number of schenkels 20 is three or four, the flexibility of the cable laid rope 10 can be ensured.

When a tensile load is applied to the cable laid rope 10, such as when a load is hung from the cable laid rope 10, the force that causes the schenkels 20 in the outermost layer to unravel acts as a force that causes the strands 30 to tighten more and the wires 40 to tighten more. Therefore, if the twisting direction of the strands 30 is the same as the twisting direction of the wires 40, it is easier to balance the force that causes the unraveling and the force that causes the tightening. As a result, it is possible to create a configuration that is less likely to rotate.

The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the spirit of the invention.

10 Cable laid rope 20 Schenkel 30 Strand 40 Wire

Claims (2)

Three or four schenkels each having a structure in which a plurality of strands are twisted together are twisted together,
The twisting direction of the schenkels is opposite to the twisting direction of the strands,
The pitch of the twist between the schenkels is 7 to 11 times the rope diameter,
Adjacent schenkels are in contact with each other,
Each of the plurality of strands is configured by twisting together a plurality of wires,
A cable laid rope in which the strands are twisted in the same direction as the wires. 2. A cable laid rope according to claim 1, having a flexibility of from 1570 to 2400.

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