JP2011047070A - Impact-absorbing rope and method for producing impact-absorbing rope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impact-absorbing rope which is excellent in a mechanical strength and in an impact-absorbing property, while having a light weight, to provide a method for producing the impact-absorbing rope, and to provide a protector. <P>SOLUTION: There is provided the impact-absorbing rope 10 prepared by twisting polyamide fibers 1, and having a diameter of 10 to 40 mm, wherein the polyamide fibers 1 have an elongation of 50 to 200%, a toughness of 200 to 400%*cN/dtex, and a boiling water shrinkage factor of 5 to 8%. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an impact absorbing rope and a method for manufacturing the impact absorbing rope.

Conventionally, in order to prevent falling objects such as stones, earth and sand, and snow from falling on roads and buildings, protective bodies have been installed on cliffs and slopes on mountainsides.
Such a protective body is generally composed of a protective net, a support post to which the protective net is attached, and a support for fixing the support post.

As such a protection body, what used the metal protection net | network and used the wire rope as a support tool is known (for example, refer patent documents 1-4).
Further, a protection body using a net (protection net) made of a synthetic fiber that is lightweight is known (for example, see Patent Document 5). In such a protective body, a holding rope is used as a support.

JP-A-61-109806 Japanese Patent Laid-Open No. 7-300820 JP-A-7-197423 Japanese Patent Laid-Open No. 2000-273727 JP 2003-261910 A

However, in the protection body of the said patent documents 1-4, since the weight of a metal protection net | network is large, the support tool which supports these needs a strong thing like a wire rope. For this reason, the construction using these members becomes large-scale and requires heavy equipment and dedicated equipment. As a result, the construction cost increases and the construction period is prolonged.
In addition, since there are many places where the above-mentioned protective body is constructed such as cliffs and slopes, there are restrictions on the use of heavy machinery and large-scale equipment, and there are also problems in workability and safety.

On the other hand, the protective body described in Patent Document 5 uses a net made of a synthetic fiber that is light in weight, and thus is improved with respect to weight.
However, a mesh made of synthetic fibers has a drawback that it is easily damaged by an impact such as falling rocks because it has a lower mechanical strength than a metal protective net. In order to suppress this breakage, a shock absorbing member that absorbs impacts such as falling rocks may be provided. However, such a shock absorbing member is generally made of a large metal, resulting in an increase in weight and construction. Such problems arise.

  The present invention has been made in view of the above circumstances, and provides a shock-absorbing rope, a shock-absorbing rope manufacturing method, and a protective body that are lightweight and have excellent mechanical strength and shock absorption. Objective.

  The inventors of the present invention have intensively studied to solve the above problems, and have thought that the use of a stretchable rope can absorb the impact of falling objects on the protective body. And it discovered that the said subject could be solved unexpectedly by making the polyamide fiber which has a predetermined characteristic into a rope, and came to complete this invention.

  That is, the present invention is (1) a shock absorbing rope having a diameter of 10 to 40 mm formed by twisting polyamide fibers, wherein the polyamide fibers have an elongation of 50 to 200% and a toughness of 200 to 400% · cN / dtex, The shock absorbing rope has a boiling water shrinkage of 5 to 8%.

  The present invention resides in (2) the impact-absorbing rope according to (1) above, wherein the recovery rate from 20% elongation is 50 to 100%.

  The present invention resides in (3) the shock absorbing rope described in the above (1), wherein the polyamide fiber is a multifilament composed of 100 to 1000 single yarns of 0.5 to 20 dtex.

  The present invention resides in (4) the shock absorbing rope according to the above (3), wherein the multifilament is further twisted.

  This invention exists in the impact-absorbing rope as described in any one of said (1)-(4) whose polyamide fiber is nylon 6 or nylon 66.

  This invention exists in the impact-absorbing rope as described in any one of said (1)-(5) whose strength is 30-100 kN and elongation is 50-300%.

  In the present invention, (7) when the length is 10 m, one end is fixed and an impact force of 20 kJ is applied to the other end in the longitudinal direction, the impact load received by one end is 16 kN or less (1) to (6 ) Exists in the shock absorbing rope according to any one of the above.

  This invention exists in the impact-absorbing rope as described in any one of said (1)-(7) used for the protective body which receives a fallen object (8).

  The present invention comprises (9) a polyamide having an elongation of 50 to 200%, a toughness of 200 to 400% · cN / dtex, a boiling water shrinkage of 5 to 8%, and a recovery rate of 50 to 100% after 20% elongation. It exists in the manufacturing method of the impact-absorbing rope which twists a fiber and makes it diameter 10-40mm.

  In the present invention, (10) polyamide fibers are twisted together through a plurality of combined yarns, and at least one of the combined yarns is twisted in a direction opposite to the direction in which the previous twist is applied. It exists in the manufacturing method of a certain impact-absorbing rope of the said (9) description.

  In the present invention, (11) a ring yarn is produced by twisting polyamide fibers having an elongation of 50 to 200%, a toughness of 200 to 400% · cN / dtex, and a boiling water shrinkage of 5 to 8%. A rope yarn is made by twisting a plurality of yarns, a strand yarn is made by twisting the rope yarns in the opposite direction to the twisting direction of the rope yarns, and a plurality of strand yarns are twisted in the opposite direction to the twisting direction of the strand yarns A raw rope, and a method for producing an impact absorbing rope having a diameter of 10 to 40 mm by heat-treating the raw rope.

  Since the shock absorbing rope of the present invention uses polyamide fiber, it is lightweight. For this reason, construction is easy and no heavy machinery or dedicated equipment is required. Moreover, construction is possible even in places where the scaffolding such as cliffs and slopes is bad.

The shock absorbing rope uses lightweight polyamide fiber as the raw yarn, and the polyamide fiber has predetermined characteristics, and therefore has excellent shock absorption. Moreover, according to the said impact absorption rope, since impacts, such as falling rocks, can be absorbed, damage is suppressed.
Accordingly, the impact absorbing rope is lightweight and has excellent mechanical strength and impact absorbability.
Further, since the shock absorbing rope causes permanent deformation when it receives an excessive shock, it is possible to easily determine the replacement time.
For these reasons, the shock absorbing rope is suitable for reinforcing a protective net for a protective body that prevents falling objects such as stones, earth and sand, and snow from falling on a road or a building, and a support rope for supporting the protective net. Used.

  The impact-absorbing rope has sufficient durability when the recovery rate from 20% elongation is 50 to 100%.

  When the shock absorbing rope is a multifilament composed of 100 to 1000 single yarns having a polyamide fiber of 0.5 to 20 dtex, the shock absorption and mechanical strength are more excellent, and the multifilament is further twisted. Among these, the mechanical strength is particularly excellent.

  When the polyamide fiber is nylon 6 or nylon 66, the impact absorbing rope is excellent in weather resistance and versatility.

  The shock absorbing rope has a strength of 30 to 100 kN and an elongation of 50 to 300%. For example, when it is used as a reinforcement rope for a protective body or a support rope for supporting the protective net, the damage is surely broken. To be suppressed.

  When the impact absorbing rope is designed to have a length of 10 m, one end is fixed and an impact force of 20 kJ is applied to the other end in the longitudinal direction, the impact load received at one end is 16 kN or less, Exhibits sufficient mechanical strength against any impact.

  According to the method for producing an impact absorbing rope of the present invention, it is possible to obtain an impact absorbing rope that is lightweight and has excellent mechanical strength and also excellent impact absorbability.

  In the above method for producing an impact absorbing rope, polyamide fibers are twisted together through a plurality of combined yarns, and at least one of the combined yarns is twisted in the direction opposite to the direction in which the fibers were twisted before. When it is applied, the mechanical strength is further improved.

Drawing 1 is an explanatory view for explaining the manufacturing method of the shock absorption rope concerning this embodiment. FIG. 2 is a front view showing an example of an embodiment of a protective body according to the present invention. FIG. 3A is a plan view showing an outline of an impact test in the embodiment, and FIG. 3B is a side view thereof.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

The shock absorbing rope according to this embodiment is made of polyamide fiber and has a diameter of 10 to 40 mm.
Since such a shock absorbing rope has a diameter of 10 to 40 mm, it has a good balance between mechanical strength (hereinafter also simply referred to as “strength”) and handleability. More preferably, the diameter is 15 to 30 mm.

The impact absorbing rope preferably has a strength of 30 to 100 kN. In addition, this intensity | strength is the value measured based on JISL2707 (polyester rope).
If the strength is less than 30 kN, the impact may be absorbed even if the strength is within the above range, and the material may break without being able to withstand the impact. If the strength exceeds 100 kN, the strength may increase. Compared with the case where it is within the above range, the rope has a diameter of 40 mm or more, so it becomes heavier and workability at the time of constructing the protective body is deteriorated.

The shock absorbing rope absorbs shock by elastic deformation and permanent deformation, and receives the shock over time. Therefore, the elongation of the shock absorbing rope is preferably 50 to 300%, more preferably 100 to 300%, and still more preferably 150 to 300%. The elongation is a value measured according to JIS L 2707 (polyester rope).
When the elongation is less than 50% as in a normal high-strength fiber rope, the impact force cannot always be sufficiently absorbed by the rope extension as compared with the case where the elongation is within the above range. Further, when the elongation exceeds 300%, compared to the case where the elongation is within the above range, there is a possibility that the impact force may reach other parts of the protective body before the impact absorbing rope exhibits the impact absorbing performance. is there.

As a measure of impact absorption of the impact absorbing rope, when the length is 10 m, one end is fixed and an impact force of 20 kJ is applied to the other end in the longitudinal direction, the fixed end (hereinafter also referred to as “fixed end”). The impact load received is preferably 16 kN or less. The impact load is a value measured by installing a strain gauge at the fixed end.
When the impact load exceeds 16 kN, the impact cannot be sufficiently absorbed as compared with the case where the impact load is within the above range. That is, when an impact absorbing rope having a low impact absorbing performance is used for a protective body such as a falling rock, the impact due to the falling rock or the like is directly applied to the support body, which may cause the protective body to collapse.

The impact absorbing rope preferably has a recovery rate of 50 to 100% after 20% elongation.
Here, the recovery rate from the 20% elongation is a value obtained by calculating the recovery rate from the elongation after stretching the yarn by 20% with a tensile tester, removing the yarn from the tensile tester and leaving it for 16 hours. is there.
When the recovery rate is less than 50%, the extension recovery performance is insufficient as compared with the case where the recovery rate is within the above range, and when the recovery rate exceeds 100%, the recovery rate is within the above range. Compared to the case, since the fiber shrinks from the length before stretching, the dimensional stability of the shock absorbing rope is lowered.

The shock absorbing rope according to this embodiment is manufactured by twisting polyamide fibers.
Examples of such polyamide fibers include nylon 6, nylon 11, nylon 12, nylon 46, nylon 66, nylon 610, and the like. These may be used alone or in combination of two or more.

Among these, the polyamide fiber is preferably nylon 6 or nylon 66.
Since the shock absorbing rope is mostly used outdoors, if the polyamide fiber is nylon 6 or nylon 66, the weather resistance is excellent. In addition, nylon 6 or nylon 66 is excellent in versatility, and can be used at a low cost for a long period of time.

The polyamide fiber has high elongation and high toughness in order to sufficiently absorb the impact.
For example, the elongation of the polyamide fiber is 50 to 200%.
If the elongation is less than 50%, it becomes insufficient to absorb the impact force by the rope extension, and if the elongation exceeds 200%, the other shock absorber ropes will not be able to absorb the shock absorbing performance before There is a risk of impact force on the part.

The toughness of the polyamide fiber is 200 to 400% · cN / dtex.
Here, toughness is a value represented by elongation (%) × strength (cN / dtex).
If the toughness is less than 200% · cN / dtex, the shock absorbing rope may not be able to withstand the impact, and the impact absorbing rope may break. If the toughness exceeds 400% · cN / dtex, the shock absorbing rope will exhibit shock absorbing performance. There is a risk that impact force will be applied to other parts of the protector before.

Polyamide fiber has a boiling water shrinkage of 5 to 8%.
Here, the boiling water shrinkage is a value measured according to the hot water shrinkage: heel shrinkage A method in JIS L1013.
The shock absorbing rope according to the present embodiment is mostly used outdoors, and is often exposed to rainwater or used in a place where a temperature change is large. For example, if the shock absorbing rope gets wet with water, even if it is dried, air bubbles and water remain inside the rope and the rope tends to stretch, so the shrinkage of the rope under wet heat will lead to dimensional stability. . If the boiling water shrinkage is less than 5%, the recovery of the rope stretched outdoors as described above will be affected, and the dimensional stability will be poor. If the boiling water shrinkage exceeds 8%, shock absorption will occur. When the rope is used, the polyamide fiber contracts due to heat, and the fiber density inside the shock absorbing rope increases, so that an effective elongation cannot be obtained, and there is a risk of performance change.

The softening point of the polyamide fiber is preferably 150 ° C. or higher.
When the softening point is less than 150 ° C, compared to the case where the softening point is within the above range, due to friction between the shock absorbing ropes when an impact is applied, or between other members, falling rocks, etc., There is a risk of performance changes.

  The polyamide fiber is not particularly limited in the fineness and the number of single yarns, but from the viewpoint of mechanical strength, the single yarn having a fineness of 0.5 to 20 dtex is a multifilament in which 100 to 1000 bundles (yarns) are formed. From the viewpoint of handleability, it is preferable that the multifilament is a bundle of 100 to 500 yarns. The polyamide fiber naturally includes untwisted yarn. Moreover, the cross-sectional form of the single yarn may be a round cross section, an irregular cross section such as an ellipse or a triangle, or a hollow.

The fineness of the obtained yarn is preferably 30 to 3000 dtex, more preferably 500 to 2500 dtex.
Moreover, it is preferable that the polyamide fiber is one in which multifilaments are further twisted. In this case, the mechanical strength is greatly improved.

  The shock absorbing rope can be suitably used as a rope for reinforcing a protective net of a protective body that catches a fallen object, a support rope that supports the protective net, a mooring rope for a ship, a safety rope for working at high places, and the like. .

  Next, a method for manufacturing the shock absorbing rope according to this embodiment will be described. In the present embodiment, an example in which nylon 6 is used as the polyamide fiber is shown.

First, a polymer chip as a raw material for polyamide fiber is synthesized by a polycondensation reaction so as to have a desired molecular weight.
The intrinsic viscosity of the polymer chip, which is a measure of the molecular weight, is preferably 0.6 to 1.2 dl / g.
Here, the intrinsic viscosity means an intrinsic viscosity at infinite dilution in a specific good solvent of the polymer. Specifically, it is indicated by a value measured in a constant temperature bath of 35 ° C. using an Ostwald viscometer after dissolving at a temperature of 100 ° C. at a rate of 1.2 g of yarn with respect to 100 ml of orthochlorophenol.
When the intrinsic viscosity is less than 0.6 dl / g, the molecular weight becomes too small as compared with the case where the intrinsic viscosity is within the above range, and a sufficiently strong polyamide fiber cannot be obtained, and the intrinsic viscosity is 1.2 dl. If it exceeds / g, the molecular weight becomes too large compared to the case where the intrinsic viscosity is in the above range, and spinning described later becomes difficult.

Next, the obtained polymer chip is kneaded and melted with an extruder or the like. At this time, the melting temperature is 250 to 320 ° C.
Then, the molten polymer is extruded from a predetermined spinneret, and a cooling zone whose temperature is appropriately adjusted is taken up at a speed of 500 to 3000 m / min to obtain an undrawn yarn. The cooling zone is divided into several stages and is set in a temperature range from room temperature to about 300 ° C.

Next, the obtained undrawn yarn is continuously supplied to the drawing step without winding up, and drawn so that the draw ratio becomes 1.0 to 3.5 times, and then set to constant length with a heat roller. A single yarn is obtained by winding, and a polyamide fiber is obtained by bundling the single yarn.
Further, in order to adjust the elongation and the dry heat shrinkage rate of the polyamide fiber, it is preferable to set the preheating temperature during drawing to 60 to 100 ° C. and the heat setting temperature to about 150 to 240 ° C.

An important production condition in the production of the polyamide fiber described above is the draw ratio.
Usually, when producing a high-strength yarn, the draw ratio is 3.0 to 5.0 times. However, since the properties necessary for the polyamide fiber of the present invention are elongation and toughness, 1.0% The draw ratio is adjusted to ˜3.5 times, more preferably 1.0 to 2.5 times.

  In the manufacturing method of the shock absorbing rope according to the present embodiment, the shock absorbing rope can be obtained by twisting polyamide fibers to have a diameter of 10 to 40 mm, preferably 15 to 30 mm.

The polyamide fibers are preferably twisted through a plurality of times.
Further, it is preferable that at least one of the combined yarns is twisted in a direction opposite to the direction in which the twist is applied before that.
In this case, the mechanical strength of the resulting shock absorbing rope is further improved.

  Specifically, as the method of twisting, it is preferable to twist 2 to 5 polyamide fibers first, and then twist 3 to 7 strands. At this time, it is preferable to twist in the opposite direction so that the twist does not return, and it is particularly preferable to repeat such an operation many times.

Drawing 1 is an explanatory view for explaining the manufacturing method of the shock absorption rope concerning this embodiment.
Here, the manufacturing method of the shock absorbing rope according to the present embodiment will be described more specifically with reference to FIG. 1. First, a single yarn of 0.5 to 20 dtex is composed of 100 to 1000 bundles (yarns). Two to five polyamide fibers 1 are twisted to produce a ring yarn S1, and a plurality of the obtained ring yarns S1 are twisted to produce a rope yarn S2. At this time, the twisting direction of the rope yarn S2 is opposite to that in the production of the ring yarn S1.
At this time, the fineness of the ring yarn S1 is preferably 1000 to 15000 dtex, and the number of single yarns is preferably 200 to 5000. The rope yarn S2 is preferably composed of 3 to 7 ring yarns S1.

Next, a strand yarn S3 is produced by twisting a plurality of rope yarns S2 in a direction opposite to the twisting direction of the rope yarn S2, and a plurality of strand yarns S3 are twisted in a direction opposite to the twisting direction of the strand yarn S3 to form a raw rope S4. And
At this time, the strand yarn S3 is preferably composed of 10 to 50 rope yarns S2, and the raw rope S4 is preferably composed of 2 to 5 strand yarns S3.

Then, the shock absorbing rope 10 is obtained by heat-treating the obtained raw rope S4.
In this case, there is an advantage that the dimensional stability of the shock absorbing rope is increased.
At this time, the heat treatment is preferably performed at a temperature of 80 to 100 ° C. for 1 to 10 minutes.

Here, the characteristics of the shock absorbing rope 10 change depending on the number of twists of each yarn. That is, as the number of twists increases, the elongation increases and the impact absorption performance increases, but the mechanical strength tends to decrease.
Further, when the number of twists is increased, the rope tends to be tightened and hardened. There is a suitable range for the number of twists in each yarn because the rope becomes too hard to handle.
In general, even with the same number of twists, thick yarns and ropes tend to be tighter than yarns and ropes. Therefore, the number of twists of each yarn is preferably set higher for the inner layer and lower for the outer layer. That is, it is preferable to reduce the number of twists in the order of ring yarn S1, rope yarn S2, strand yarn S3, and raw rope S4.
As a result, the shock absorbing rope 10 effectively extends and absorbs the impact while maintaining the mechanical strength when the impact is applied.

Specifically, the twist number of the ring yarn S1 is preferably 70 to 150 T / m, and more preferably 100 to 130 T / m.
When the number of twists is lower than 70, the elongation becomes insufficient as compared with the case where the number of twists is within the above range, and when the number of twists is higher than 150, the number of twists is within the above range. The strength becomes low and the toughness becomes insufficient.

The number of twists of the rope yarn S2 for twisting the ring yarn S1 is preferably 60 to 130 T / m, and more preferably 80 to 120 T / m.
When the twist number is lower than 60, the elongation is similarly insufficient as compared with the case where the twist number is within the above range, and when the twist number is higher than 130, the twist number is within the above range. As a result, the toughness is insufficient.

The number of twists of the strand yarn S3 for twisting the rope yarn S2 is preferably 20 to 100 T / m, and more preferably 40 to 90 T / m.
When the number of twists is lower than 20, when the number of twists is within the above range, the elongation is similarly insufficient. When the number of twists is higher than 100, the number of twists is within the above range. As a result, the toughness is insufficient.

The number of twists of the raw rope S4 for twisting the strand yarn S3 is preferably 10 to 40 T / m, and more preferably 15 to 35 T / m.
When the number of twists is lower than 10, compared with the case where the number of twists is in the above range, the convergence property of the strand yarn S3 is deteriorated. When the number of twists is higher than 40 T / m, the number of twists is in the above range. Compared to the case, the shock absorbing rope 10 becomes too hard and difficult to handle.

In the manufacturing method of the impact absorbing rope 10, it is preferable that the twist coefficient of each yarn is 0.5-3.
Moreover, about the raw rope S4 of the outermost layer, in order to prevent becoming too hard, it is preferable that a twist coefficient shall be 0.5-2.

It is preferable that at least a part of the polyamide fiber is impregnated with resin in the impact absorbing rope.
In this case, twist back is suppressed. In addition, a moderate waist can be imparted to the shock absorbing rope, and the handleability is improved.

As a resin impregnation method, when producing a strand yarn, a portion of the rope yarn is impregnated with the resin, and the rope yarn impregnated with the resin and the rope yarn not impregnated with the resin are twisted to produce the strand yarn. Is preferred.
At this time, the ratio of the rope yarn impregnated with the resin in the strand yarn is preferably 1/3 to 1/2.

  Examples of the resin used for such resin impregnation include acrylic resins, vinyl acetate resins, and polyester resins.

The impact absorbing rope has a pigment, an ultraviolet absorber, a resin, a flame retardant, a heat stabilizer for the purpose of improving weather resistance, wear resistance, thermal stability, smoothness, imparting functionality, and stability of form. In addition, components such as an oil agent, a smoothing agent, and an antibacterial agent may be contained.
In particular, when the shock absorbing rope is used outdoors, it is effective to blend a pigment or an ultraviolet absorber or coat a resin. Further, when an oil agent is applied when twisting polyamide fiber to make an impact absorbing rope, fluff and thread breakage due to friction can be suppressed, which is effective. There is no restriction | limiting in particular in such various additives, What is necessary is just to use what is thought to be effective suitably.

  The shock absorbing rope can be suitably used as a rope for reinforcing a protective net of a protective body that catches a fallen object, a support rope that supports the protective net, a mooring rope for a ship, a safety rope for working at high places, and the like. .

Next, a protective body using the shock absorbing rope will be described.
FIG. 2 is a front view showing an example of an embodiment of a protective body according to the present invention.
As shown in FIG. 2, the protective body 20 according to the present embodiment supports the protective net 11 made of a mesh-like synthetic fiber, the peripheral rope 12 provided on the peripheral edge of the protective net 11, and the protective net 11. The support rope 13 includes a support 15 that is disposed on both sides of the protective net 11 and to which the support rope 13 is attached, and a support 17 that supports the support 15.
The protective body 20 includes three auxiliary ropes 18 supported by the support column 15 and attached linearly to the back surface of the protective net 11.

  In the protective body 20, the shock absorbing rope described above is used for the peripheral rope 12, the support rope 13 and the auxiliary rope 18. In addition, what is necessary is just to adjust mechanical strength, elongation, and the number of the said shock absorption rope according to the scale of the falling rock etc. anticipated in the place where it is constructed. Further, when the protective body 20 is installed on a slope, the auxiliary rope 18 is provided on the valley side.

  The shock absorbing ropes used for the peripheral rope 12, the support rope 13, and the auxiliary rope 18 may not have the same characteristics. Alternatively, the shock absorbing rope as the peripheral rope 12 and the shock absorbing rope as the support rope 13 may be integrated.

The protective body 20 has a structure in which falling objects such as stones, earth and sand, and snow are received by the protective net 11. That is, when there is a fallen object, the protective body 20 is stretched by the peripheral rope 12 and the support rope 13, so that the protection net 11 is bent and the impact force when the fallen object falls is absorbed.
Moreover, in the said protection body 20, since the auxiliary rope 18 is attached, it is suppressed that the protection net | network 11 expands locally by a fallen object, and it breaks, and the impact by a fallen object is absorbed also by the auxiliary rope 18. FIG. The The auxiliary ropes 18 may alternately pass through the mesh of the protection net 11 or may be arranged in parallel with the protection net 11 so as to contact the lower surface of the protection net 11 without passing through the mesh.

Thus, according to the protective body 20, since the protective net 11 made of synthetic fiber and the shock absorbing rope made of polyamide fiber are used, the protective body 20 can be reduced in weight and the impact can be sufficiently reduced.
Therefore, since an impact such as falling rocks can be absorbed, damage to the members of the protective body 20 is suppressed.
Moreover, the said protection body 20 is easy to construct, and does not require heavy machinery or dedicated equipment. Moreover, construction is possible even in places where the scaffolding such as cliffs and slopes is bad.

As the protective net 11, a net made of metal or organic fiber is used.
Here, the shock absorbing rope of the present invention has a feature of light weight in addition to mechanical properties and shock absorbency, and by combining it with an organic fiber net that is generally lighter than a metal net, the feature can be further utilized, It is effective for workability and safety.

  The organic fiber is not particularly limited, but a high-strength and high-elastic material is suitable for catching falling rocks. Polyolefins such as polyethylene and polypropylene, polyarylate, polyethylene terephthalate, polyethylene naphthalate, polybutylene Polyesters such as terephthalate, polyamides such as polyamide 6, polyamide 11, polyamide 12, polyamide 46, and polyamide 66, aramids such as polyparaterephthalamide and polymetaterephthalamide, polybenzoxazole, and carbon fibers. These may be used alone or in combination of two or more.

The protective net 11 is not particularly limited in the knitting configuration, and may be either a knot type or a no-knot type.
The shape, size (mesh), and thickness of the protective net 11 are not limited, and may be determined as appropriate according to the scale of rock fall or the like expected at the place where the protective net 11 is installed.

The strut 15 is appropriately designed in strength, structure, etc. according to the scale of rock fall expected at the place where it is constructed.
For example, concrete struts, and structures composed of concrete and steel pipes embedded in basic concrete or underground can be used. In addition, when standing rock fall is expected to be relatively small, natural standing trees may be used as struts.

As the support 17, a conventional one is used as appropriate.
Since the protective body 20 is lightweight, it is not always necessary to make the support 17 robust. However, from the viewpoint of improving safety, the protective body 20 may be robust such as a wire rope.

The protector 20 may include a shock absorber (not shown).
As such a shock absorber, a fiber rope is preferably used.
Examples of the rope fiber include synthetic fibers such as polyamide fiber, polyester fiber, vinyl chloride fiber, and polypropylene fiber, and natural fibers such as hemp.

According to the protective body 20 according to the present embodiment, as described above, the protective body 20 can be reduced in weight, and the impact can be reduced by using an impact absorbing rope. For this reason, construction is easy and no heavy machinery or dedicated equipment is required. Moreover, construction is possible even in places where the scaffolding such as cliffs and slopes is bad.
Moreover, since the impact absorbing rope described above is used, it is possible to absorb impacts such as falling rocks and the damage of the members of the protective body 20 is suppressed.
In addition, the shock absorbing rope described above is light and excellent in workability, so it is easy to replace a rope damaged by falling rocks, etc., and whether it is damaged or not is easily confirmed by how much permanent deformation has occurred. Therefore, appropriate maintenance and early member replacement are possible. Therefore, the performance of the protective body 20 can be maintained at a high level.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

Example 1
Three polyamide fibers with elongation of 100%, toughness of 350% · cN / dtex, and fineness of 1400 dtex are twisted in the S twist direction at 120 T / m to form a ring yarn, and these four ring yarns are 110 T in the Z twist direction. A rope yarn was produced by twisting at a distance of / m. Furthermore, 30 rope yarns obtained were twisted together at 50 T / m in the S twist direction to produce rope strands. At this time, the rope yarn was impregnated with a polyester resin in advance so as to be 1% by weight after drying. Three rope strands were twisted in the Z twist direction at 20 T / m to obtain a fiber rope. This was preheated at 80 ° C. and heat-treated at 100 ° C. to obtain a rope A having a diameter of 20 mm.

(Example 2)
A rope B having a diameter of 20 mm was obtained in the same manner as in Example 1 except that a polyamide fiber having an elongation of 50%, a toughness of 250% · cN / dtex, and a fineness of 1400 dtex was used.

(Comparative Example 1)
A rope C having a diameter of 20 mm was obtained in the same manner as in Example 1 except that a polyamide fiber having an elongation of 20%, a toughness of 182% · cN / dtex, and a fineness of 1400 dtex was used.

(Comparative Example 2)
A rope D having a diameter of 22 mm was obtained in the same manner as in Example 1 except that three polyester fibers (P949ML, fineness 2110 dtex) manufactured by Teijin Fibers Ltd. were twisted to form a ring yarn.

(Comparative Example 3)
A metal wire rope (6 × 7 (JIS standard product), 10 mm diameter, strength 52 kN) manufactured by Otsuna Corporation was used as the rope E.

(Comparative Example 4)
A rope F having a diameter of 44 mm was obtained in the same manner as in Example 1 except that 150 rope yarns were twisted to produce a rope strand.

(Evaluation methods)
The ropes A to D obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were evaluated based on the following measurement methods.

(1) Rope strong elongation (strength and elongation)
It measured based on JIS L2707 (polyester rope) using the A & D company Tensilon testing machine. The obtained results are shown in Table 1.

(2) Boiling water shrinkage rate Hot water shrinkage rate in JIS L 1013: Measured in accordance with the wrinkle shrinkage rate A method. That is, the yarn is wound 10 times with a measuring instrument to produce a ridge (n number is 3). Then, the length of the heel is read by applying an initial load (g) of yarn fineness (dtex) × (9/10) × 20 × 1/30. This corresponds to a (1/30) load of the total fineness (de). Next, the bag is wound on gauze, treated in boiling water for 30 minutes, and then taken out. After drying the cocoon, leave it in the laboratory at room temperature overnight, and then measure the cocoon length again under the same load as before boiling water treatment. The shrinkage rate was calculated from these differences. The obtained results are shown in Table 1. In Table 1, the rope constituent yarn characteristics are obtained by disassembling the processed ropes A to D and measuring the characteristics of the constituent yarns.

(3) Recovery rate from 20% elongation Mark the thread with a certain length (100 mm) with a magic. The yarn is stretched by 20% with a tensile tester at room temperature (100 → 120 mm). The yarn is removed from the tensile tester and left overnight (16 hours) in the laboratory / room temperature. The length of the fixed length (100 mm) was measured again, and the recovery rate from the elongation was calculated.

(4) Impact load test A strain gauge is installed at the bottom of a gantry fixed horizontally in a stable location. Secure one end of the ropes A to D to the strain gauge with a knot or the like. Similarly, a 2t weight is fixed to the other end of the ropes A to D. The test length of the ropes A to D is adjusted to 10 m. From the height at which the ropes A to D naturally hang down from the strain gauge, the weight is lifted by 1 m and dropped using a crane or the like (energy amount 20 kJ). The value measured with the strain gauge at that time was taken as the impact load. The obtained results are shown in Table 1. In the table, the “initial” of the rope elongation is immediately after, and the “final” is a measurement of the elongation (%) of the rope after standing overnight (16 hours) at room temperature (25 ° C.).

(5) Impact Test FIGS. 3A and 3B are diagrams showing an outline of the impact test.
As shown in FIG. 3, a 3 m × 2 m size polyester net 21 was placed so as to be horizontal with the ground, and the ropes A to D were passed through the outermost net as the peripheral rope 22.
Then, the peripheral rope 22 at the four corners of the polyester net 21 was fixed to the gantry 25 through the strain gauge 23.
A weight 26 of 1 t was dropped from the height of 2 m above the center of the polyester net 21 (energy amount 20 kJ). The state of the ropes A to D at this time was observed, and the load applied to the strain gauge 23 was measured. The obtained results are shown in Table 1. In the table, the “initial” of the rope elongation is immediately after, and the “final” is a measurement of the elongation (%) of the rope after standing overnight (16 hours) at room temperature (25 ° C.).

(result)
The rope A of Example 1 was not only lightweight but also flexible, easy to handle and excellent in workability. The recovery rate from the 20% elongation of this rope was 75%.
Immediately after the impact load test or impact test, the rope was stretched by 17 to 32% in length, but after that, the rope was stretched and recovered, and the final permanent deformation was 7 to 14%. The rope was not cut and had excellent impact resistance.

The rope B of Example 2 was not only lightweight but also flexible, easy to handle and excellent in workability. The recovery rate from the 20% elongation of this rope was 60%.
Immediately after the impact load test or impact test, the rope was stretched by 10 to 20%, but after that, the rope was stretched and recovered, and the final permanent deformation was 5 to 8%. The rope was not cut and had excellent impact resistance.

Rope C of Comparative Example 1 had a recovery rate of 46% after 20% elongation.
In addition, despite the higher strength than the ropes of Examples 1 and 2, as a result of the impact load test, the load measured by the strain gauge is not much different from the applied impact load and absorbs less impact force. It wasn't.
Furthermore, as a result of performing an impact test using this rope, the impact was transferred to the polyester net without relaxation, and the net was broken.

The rope D of Comparative Example 2 was not only lightweight but also flexible, easy to handle and excellent in workability. The recovery rate from the 20% elongation of this rope was 30%.
Further, immediately after the impact load test and the impact test were performed, the rope was stretched by 15 to 22% in length. The final permanent deformation after stretching recovery was 14 to 21%, and it did not have sufficient stretching recovery performance.

  As a result of an impact load test, the rope E of Comparative Example 3 was 20 kJ, which was the same as the applied impact load, and did not absorb any impact force. Moreover, as a result of performing an impact test using this metal wire rope, the impact was directly transmitted to the polyester net, and the net was broken.

  The rope F of Comparative Example 4 was flexible but heavy and inferior in workability. The recovery rate from the 20% elongation of this rope was 69%.

[Table 1]

  From Table 1, the ropes A and B of Examples 1 and 2 have excellent toughness (strength x elongation), so absorb 20% or more of the impact load and effectively prevent net breakage. I found out. Further, the recovery rate from 20% elongation was high, and the impact recovery test and the elongation recovery performance after the impact test were also high. From this, according to the shock absorbing rope of the present invention, it was confirmed that it can be used repeatedly because it is lightweight but has excellent mechanical strength and stretch recovery performance.

  In the impact absorbing ropes in Examples 1 and 2, the number of twists of each yarn is set higher in the inner layer and lower in the outer layer. The present inventor has confirmed in advance that the shock absorbing rope 10 can effectively stretch and absorb the shock while maintaining the mechanical strength when the shock is applied.

DESCRIPTION OF SYMBOLS 1 ... Polyamide fiber 10 ... Shock absorption rope 11 ... Protective net 12, 22 ... Perimeter rope 13 ... Support rope 15 ... Post 17 ... Support tool 18 ... Auxiliary rope DESCRIPTION OF SYMBOLS 20 ... Protective body 21 ... Polyester net 23 ... Strain gauge 25 ... Mounting stand 26 ... Weight S1 ... Ring yarn S2 ... Rope yarn S3 ... Strand yarn S4 ...・ Raw rope

Claims (11)

An impact absorbing rope having a diameter of 10 to 40 mm formed by twisting polyamide fibers,
The impact-absorbing rope, wherein the polyamide fiber has an elongation of 50 to 200%, a toughness of 200 to 400% · cN / dtex, and a boiling water shrinkage of 5 to 8%.   The impact-absorbing rope according to claim 1, wherein a recovery rate from 20% elongation is 50 to 100%.   The shock absorbing rope according to claim 1, wherein the polyamide fiber is a multifilament composed of 100 to 1000 single yarns of 0.5 to 20 dtex.   The shock absorbing rope according to claim 3, wherein the multifilament is further twisted.   The shock absorbing rope according to any one of claims 1 to 4, wherein the polyamide fiber is nylon 6 or nylon 66.   The impact absorbing rope according to any one of claims 1 to 5, wherein the strength is 30 to 100 kN and the elongation is 50 to 300%.   The impact according to any one of claims 1 to 6, wherein when the length is 10 m, one end is fixed and an impact force of 20 kJ is applied to the other end in the longitudinal direction, the impact load received by the one end is 16 kN or less. Absorption rope.   The impact-absorbing rope according to any one of claims 1 to 7, which is used for a protective body that receives a fallen object.   A polyamide fiber having an elongation of 50 to 200%, a toughness of 200 to 400% · cN / dtex, a boiling water shrinkage of 5 to 8%, and a recovery rate of 50 to 100% after 20% elongation is twisted to obtain a diameter of 10 A method for producing an impact-absorbing rope of ˜40 mm The polyamide fiber is twisted through a plurality of combined yarns,
The method for producing an impact-absorbing rope according to claim 9, wherein at least one of the combined yarns is twisted in a direction opposite to a direction in which the twist is applied before.   A polyamide yarn having an elongation of 50 to 200%, a toughness of 200 to 400% · cN / dtex, and a boiling water shrinkage of 5 to 8% is twisted to produce a ring yarn, and a plurality of the ring yarns are twisted together. A rope yarn is prepared, a plurality of the rope yarns are twisted in the opposite direction to the twisting direction of the rope yarn to produce a strand yarn, and a plurality of the strand yarns are twisted in the opposite direction to the twisting direction of the strand yarn to obtain a raw rope. A method of manufacturing an impact absorbing rope having a diameter of 10 to 40 mm by heat-treating.

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