JP6223689B2 - Impact load relaxation rope and lanyard - Google Patents

Description

  The present invention relates to a lanyard provided to connect a safety belt worn by an operator at high altitude to a structure and the like, and an impact load relaxation rope used for a rope of the lanyard.

In general, workers at high altitudes wear safety belts in case of a fall.
This safety belt includes a lanyard in which a hook (or carabiner) is connected to the tip of a rope or strap.
An operator should hook the lanyard hook or the like to a master rope or a solid structure, and connect a safety belt wound around the worker's body to the structure or the like via the lanyard. , To prevent a fall when you stepped on.

By the way, the material of the rope used for the lanyard is generally a synthetic fiber, and a three-strand rope in which three strands are twisted and eight strands are knitted due to the difference in the configuration. Eight-strand rope, or a double-blade rope in which a plurality of strands are coated with an outer layer.
The ropes used in these lanyards stretch and absorb the impact load when dropped, but the three-strand ropes tend to kinks and require care in handling. Here, “kink” is a phenomenon in which the rope twists and loses its shape, and the occurrence of the kink causes the strength of the rope to decrease.

The eight-strike rope is softer and less likely to kink than the three-strand rope, but the knitting method is loose, so that, for example, a strand may easily protrude when caught on a protrusion or the like.
Since the double braided rope has a plurality of strands coated with an outer layer, it is easy to handle without generating kinks or protruding strands, and has good weather resistance.
In addition, the three-strand rope and the eight-strand rope require a process called “satsuma knitting” that is manually performed by a skilled worker as a terminal process, but the double-blade rope is sewn by an automatic sewing machine. The terminal processability is also good.
However, double blade ropes are less stretched than three-strand ropes and eight-strand ropes, and thus there is a problem that the impact load received by the wearer of the safety belt becomes large when dropped and suspended in the air.

On the other hand, there are two types of safety belts to which the lanyard is connected: a belt type and a harness type. Compared with the belt type safety belt, the harness type safety belt distributes the impact load at the time of dropping. There is a feature that can reduce the damage to the person's body.
In addition, an operator wearing a harness-type safety belt can maintain a stable posture until being rescued from a suspended state.
For these reasons, the harness type safety belt has been used more frequently than the body belt type. This is because the impact load at the time of dropping is dispersed, while the impact load is It may be larger than the waist belt type safety belt.
In other words, the drop distance of the worker at the time of the fall is affected by the difference in height between the position where the hook at the tip of the lanyard is hooked to the structure and the connection position with the worker at the base end of the lanyard. However, in the case of the waist belt type safety belt, the connection position with the worker is the human waist, whereas in the case of the harness type safety belt, the connection position with the worker is the back of the human body. The connection position is higher than the belt belt type safety belt. For this reason, if the latching position with respect to the structure or the like is the same, the safety distance of the harness type is longer than the safety belt of the body belt type, and the drop distance of the worker is increased, and the impact load at the time of dropping is increased. .

Therefore, the lanyard used for the harness-type safety belt is required to have better shock absorption performance than the lanyard used for the body belt-type safety belt.
Therefore, a lanyard equipped with a shock absorber has been developed as a lanyard used for a harness-type safety belt.
By the way, when a double blade rope is used as a lanyard rope used in a harness type safety belt, if the lanyard is not equipped with a shock absorber, the maximum impact load at the time of falling becomes large, and `` safety belt standards '' It is known that the value (drop impact load of 8 kN or less) defined in the above cannot be cleared.

Here, as the shock absorber, for example, the fiber belt is folded in the length direction, the overlapped portion is stitched in multiple lines, and when an impact load is applied at the time of dropping, the suture is broken to apply the impact load. In addition to the type that relaxes, there is a type that, when weaving the fiber belt, weaves a weak yarn in advance, and when an impact load is applied during the fall, breaks the weak yarn to absorb and relax the impact load. .
However, since any type of shock absorber is separate from the lanyard rope and has a considerable thickness, it may become an obstacle around the waist when a safety belt is attached. Also, the shock absorber may swing, causing trouble.
Furthermore, since the suture thread and the pre-woven thread are cut, the fall distance becomes large, and there is a possibility of crashing into the ground or the like.

On the other hand, among lanyard ropes, there are those disclosed in the following Patent Documents 1, 2, and 3 as ropes having an impact load relaxation function.
In the lanyard rope disclosed in Patent Document 1, the core yarn, which is the central portion of the rope, is composed of a low elongation yarn, the intermediate layer outside the core yarn is a high elongation yarn, and the intermediate layer The skin layer covering the material is also composed of high-strength yarn.
Thereby, when a large load is applied to the rope of the lanyard, only the core yarn is cut and the fall energy is absorbed.
However, the elongation of the rope is determined by the elongation of the yarn itself forming the strand, the twisting method of the strand (the twisted rope having a larger strand angle with respect to the length direction of the rope has a higher elongation), etc. In this lanyard, the intermediate layer mainly responsible for the drop impact load is not a twisted rope.
For this reason, in this lanyard rope, the intermediate layer cannot absorb and relieve the drop impact load greatly, and the fall energy is absorbed only by cutting the core yarn. Accordingly, when a heavy worker or the like uses, the drop impact load may not be sufficiently relaxed.

The lanyard rope disclosed in Patent Document 2 is composed of an inner layer composed of a three-strike rope and an outer layer composed of a three-strike rope.
In this lanyard rope, the materials of the three-ply rope in the inner layer and the outer layer are different from each other, and the inner layer and the outer layer are synchronized to reduce the drop impact load by changing the elongation of the inner layer and the outer layer. I have to.
Therefore, when the worker falls, the inner and outer layers stretch, and the drop impact load is relaxed (drop energy is absorbed), but the relaxation of the drop impact load caused by the elongation of the inner layer and outer layer takes some time. It does not absorb the fall energy in a very short time.
The action time of the drop impact load generated at the time of dropping is a short time of about 0.3 to 0.4 seconds, and it may not be sufficient to absorb the drop impact load due to the extension of the inner layer and the outer layer. That is, the rope itself can be stretched over a certain amount of time to reduce the drop impact load, but the shock absorbing performance in a very short time is low.

  Patent Document 3 discloses an elastic fiber rope in which the elongation of the inner layer is different from the elongation of the outer layer. This elastic fiber rope is an auxiliary rope for performing ocean observation, underwater / bottom exploration, etc. The rope is thick and heavy. For this reason, it is difficult for an operator to attach such an elastic fiber rope, and it is not applicable to a lanyard.

Japanese Examined Patent Publication No. 52-12304 (Fig. 2) JP-A-8-311787 (paragraph number [0003], FIG. 1) JP-A-8-284075 (paragraph number [0004], FIG. 3)

Since conventional lanyard ropes are configured as described above, when a safety belt is attached, use a rope that has a shock load mitigating function rather than a lanyard that is equipped with a shock absorber that becomes an obstacle. An improved lanyard can improve the workability of workers. However, in the case of a lanyard that absorbs the drop energy only by cutting the core yarn (Patent Document 1), the drop impact load cannot be sufficiently relaxed, for example, a heavy worker who is subjected to a large drop impact load when dropped. There was a problem that it may not be suitable.
In addition, in the case of a lanyard that relaxes the drop impact load by extending the inner layer and the outer layer (Patent Document 2), it cannot sufficiently absorb the short-time drop energy that acts at the time of the drop, and a large drop impact load is still applied. There was a problem that it may not be suitable for workers who add a lot of weight.

The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain an impact load relaxation rope that can sufficiently absorb fall energy in a short time when dropped.
It is another object of the present invention to provide a rope that has a shock absorber function in the rope itself to relieve the maximum impact load when dropped and a lanyard using the rope.

The impact load relaxation rope according to the present invention includes an inner layer which is a rope body formed by braiding or twisting a plurality of strands (hereinafter referred to as braiding) and an outer layer covering the inner layer, and the inner layer and A tension member that is lower in elongation than the outer layer and is cut by a tensile load of a predetermined value or more while the inner layer and the outer layer are stretched by the action of a tensile load is disposed between the inner layer and the outer layer. Yes.
According to this configuration, when a large tensile load is applied to the impact load relaxation rope, the tension member is stretched and cut while the inner layer and the outer layer are stretched, so that the stretching speed of the inner layer and the outer layer is suppressed. The Therefore, if this is used for a lanyard, more falling energy can be absorbed, and the maximum impact load acting on the wearer of the safety belt is reduced.

In the impact load relaxation rope according to the present invention, the tension member may be coated with a resin in order to increase the frictional force between the inner layer and the outer layer.
According to this configuration, when a large drop impact load is applied, the tension member is cut at a plurality of locations in the longitudinal direction, so that the absorbable fall energy can be increased and the maximum impact load is more effective. Can be relaxed.

The impact load relaxation rope according to the present invention may be configured such that the tension member is bonded to at least one of the inner layer and the outer layer in order to increase the frictional force between the inner layer and the outer layer.
According to this configuration, when a large drop impact load is applied, the tension member is similarly cut at a plurality of locations in the longitudinal direction, so that the absorbable fall energy can be increased, and the maximum impact load can be increased. Can be mitigated more effectively.

In the impact load relaxation rope according to the present invention, a plurality of tension members may be arranged between the inner layer and the outer layer.
According to this configuration, when a large drop impact load is applied, similarly, a plurality of tension members are cut at several places, so that the absorbable fall energy can be increased.

In the impact load relaxation rope according to the present invention, a plurality of tension members having different elongations may be arranged between the inner layer and the outer layer.
According to this configuration, when a large drop impact load is applied, tension members having different elongations are sequentially cut with a time difference, so that the absorbable fall energy can be increased.

In the impact load relaxation rope according to the present invention, the number of yarns constituting each tension member may be different so that the tension members can be easily cut.
According to this configuration, when a large drop impact load is applied, the tension member is cut in order from the smallest number of raw yarns, so that the absorbable fall energy becomes high.

In the impact load relaxation rope according to the present invention, the twisting methods of the raw yarns constituting each tension member may be different from each other.
According to this configuration, when a large drop impact load is applied, tension members having different elongations due to differences in twisting are cut in order from those with lower elongation, and the time during which the impact load acts is reduced. The maximum impact load can be reduced by increasing the length.

In the impact load relaxation rope according to the present invention, the material of the raw yarn constituting each tension member may be different.
According to this configuration, since a plurality of tension members having different elongations due to differences in materials are interposed between the inner layer and the outer layer, when a large drop impact load is applied, the tensile strengths are increased in order from the smallest. It will be cut and the fall energy which can be absorbed is raised.

In the impact load relaxation rope according to the present invention, a tension member having a lower elongation than other strands is used for all or part of a plurality of strands forming the inner layer or all or part of the core material. You may do it.
According to this configuration, it is possible to reduce the maximum impact load by extending the time during which the impact load acts.

The impact load relaxation rope according to the present invention is a tension that is lower in elongation than other strands in all or some of the plurality of strands forming the inner layer or all or some of the core yarns. A member may be used.
According to this configuration, it is possible to reduce the maximum impact load by extending the time during which the impact load acts.

  The lanyard according to the present invention includes an inner layer that is a rope body formed by weaving a plurality of strands and the like, and an outer layer that covers the inner layer, and has a lower elongation and a tensile load than the inner layer and the outer layer. A tension member that is cut by a tensile load greater than or equal to a predetermined value while the inner layer and the outer layer are extended by acting, an impact load relaxation rope disposed between the inner layer and the outer layer, and an impact load relaxation rope A first connecting member for connecting one end to a safety belt worn by an operator, and a second connecting member for connecting the other end of the impact load relaxation rope to a support portion for preventing fall in the work place. It is a thing.

Further, according to the present invention, since the tension member is arranged between the inner layer and the outer layer, when a large drop impact load is applied, the tension member is cut to suppress the extension speed of the outer layer and the inner layer. Therefore, it is possible to reduce the maximum impact load by increasing the time during which the impact load acts on the rope.
Further, according to the lanyard using the impact load reducing rope according to the present invention, since the rope itself has a shock absorber function, it is not necessary to provide a shock absorber that is troublesome to manufacture in the safety belt. Therefore, the manufacturing cost of the safety zone is reduced.

It is a side view which shows the lanyard by Embodiment 1 of this invention. It is sectional drawing which shows the impact load relaxation rope by Embodiment 1 of this invention. It is a side view which shows a part of impact load relaxation rope by Embodiment 1 of this invention. It is sectional drawing of the impact load relaxation rope with which two tension members are distribute | arranged between the inner layer and the outer layer. It is sectional drawing of the impact load relaxation rope with which four tension members are distribute | arranged between the inner layer and the outer layer. 4 is a cross-sectional view of an impact load relaxation rope in which four tension members are arranged between an inner layer and an outer layer, and tension members are used as a part of a plurality of strands forming the inner layer. FIG. . FIG. 4 is a cross-sectional view of an impact load relaxation rope in which four tension members are arranged between an inner layer and an outer layer, and a core material forming the inner layer is a tension member. Four tension members are disposed between the inner layer and the outer layer, the tension member is used as a part of a plurality of strands forming the inner layer, and the core material is an impact load. It is sectional drawing of a relaxation rope. It is explanatory drawing which shows the load elongation curve of an impact load relaxation rope. It is explanatory drawing which shows the drop impact load applied to the impact load relaxation rope in which the tension member is not inserted. It is explanatory drawing which shows the drop impact load applied to the impact load relaxation rope in which the tension member is inserted between the inner layer and the outer layer. It is explanatory drawing which shows the drop impact load applied to the impact load relaxation rope when a tension member is cut | disconnected in the several location of a longitudinal direction. It is explanatory drawing which shows the drop impact load applied to the impact load relaxation rope when a tension member is cut | disconnected in the several location of a longitudinal direction. It is explanatory drawing which shows the drop impact load applied to the impact load relaxation rope when a tension member is cut | disconnected in the several location of a longitudinal direction.

Hereinafter, the impact load relaxation rope of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a side view showing an impact load relaxation rope according to Embodiment 1 of the present invention.
In FIG. 1, an impact load relaxation rope 1 is a so-called double blade rope having an inner layer formed of a rope body formed by weaving a plurality of strands and a cylindrical outer layer covering the inner layer. ,
While the inner layer and the outer layer are lower in elongation, and when the tensile load is applied and the inner layer and the outer layer are stretched, a tension member that is cut when a tensile load of a predetermined value or more is applied is between the inner layer and the outer layer. It is constituted by being arranged in.
The double blade rope has an inner layer formed by knitting or twisting a plurality of strands, and an outer layer arranged on the outer periphery of the inner layer and formed by knitting or twisting a plurality of strands. Including those consisting of
At both ends of the impact load relaxation rope 1, there are provided eye portions 1a and 1b which are ring-shaped portions, which are sewn by, for example, an automatic sewing machine.

Specifically, FIG. 2 is a cross-sectional view showing an impact load relaxation rope according to Embodiment 1 of the present invention, and FIG. 3 is a side view showing a part of the impact load relaxation rope according to Embodiment 1 of the present invention. . In FIG. 3, in order to facilitate understanding of the configuration of the impact load relaxation rope 1, the outer layer of the impact load relaxation rope 1 is illustrated in the right side portion in the drawing.
2 and 3, the inner layer 11 which is the rope body of the impact load relaxation rope 1 is a rope formed by weaving (or twisting) a plurality of strands 11a, and 16 strands are knitted. An example of a 16-stroke rope is shown.

However, the rope main body constituting the inner layer 11 is not particularly limited in the way of knitting or twisting constituting the rope.
Thus, the inner layer 11 may be, for example, a three-strand rope twisted using three strands, or a four-strand stranded around a central core using four strands. Rope, 6 strands using 6 strands, 6 strands twisted around the center core, 7 strands twisted using 7 strands, 8 strands braided It may also be a 12-strand rope that is twisted using 12 strands.
Alternatively, two strands may be used as one set, and four sets of these may be used to form a 2 × 4 striking rope, or two strands may be used as one set and six sets may be used. A x6 rope may be used.

The strand 11a can be described in terms of its configuration, for example, by collecting a large number of yarns, each of which is a collection of yarns made of high elongation fibers, and bundling them together, or twisting the bundles in parallel or by twisting them with long leads. It is configured.
Further, the core material is composed of a core tape or a core strand, and the core strand collects, for example, a bundle of many yarns of general-purpose fiber yarns selected from nylon, polyester, etc., and bundles the bundle. A strand is formed by aligning in parallel or twisting with a long lead, and a plurality of strands are twisted together.
The core strand may be a single core strand or a plurality of core strands.
Moreover, although the said core tape formed the synthetic resin in strip | belt shape, it may be formed by weaving the said general purpose fiber yarn in strip | belt shape.

Since the inner layer 11 absorbs impact by elongation when a drop impact load is applied, the yarn yarn of the strand 11a is made of high elongation fiber that can absorb the fall energy by elongation.
In the first embodiment, the high elongation fiber is preferably in the range of 30% to 40%, for example, as the breaking elongation of the yarn yarn of the strand 11a forming the inner layer 11.
For the inner layer 11, a raw yarn corresponding to this range may be appropriately selected and used. For example, general-purpose synthetic fiber yarns such as nylon and polyester are used.

The outer layer 12 is a cylindrical bag (braided cover) that is formed by weaving (or twisting) a plurality of strands 12a and covers the inner layer 11, and exists throughout the inner layer from one end to the other end. doing.
The outer layer 12 may be a cylindrical bag (braided cover) that can cover the inner layer 11, and the structure of the cylindrical bag (braided cover) of the outer layer 12 is arbitrary, but in general, 2 × 24, A dense one such as 2 × 32 is preferable.

Since the outer layer 12 plays a role of improving wear resistance and weather resistance as the impact load relaxation rope 1, the yarn yarn of the strand 12 a constituting the outer layer 12 has high elongation that can absorb fall energy by elongation. Fiber is used.
In the first embodiment, the high elongation fiber is, for example, 30% to the breaking elongation of the yarn of the yarn of the strand 12a forming the outer layer 12, as in the elongation of the yarn of the strand 11a of the inner layer 11. A range of 40% is preferable.
A raw yarn corresponding to this range may be appropriately selected and used. For example, general-purpose synthetic fiber yarns such as nylon and polyester are used. However, since the outer layer 12 has a role different from that of the inner layer 11, it is not necessarily required to be made of the same material as the inner layer 11.
In addition, the outer layer 12 plays a role of improving wear resistance and weather resistance, and when it plays a role of improving visibility during night work, use nylon in which a phosphorescent material is mixed in the raw yarn or the like. May be.

The tension member 13 is disposed between the inner layer 11 and the outer layer 12, and has a lower elongation than the inner layer 11 and the outer layer 12, and a predetermined value while the inner layer and the outer layer are stretched due to a tensile load. It is a member that is cut when the above tensile load is applied.
The cutting of the tension member 13 is a part in the longitudinal direction, and the entire cross-sectional direction is cut.
The tension member 13 is formed by collecting a plurality of low-tensile high-tensile fibers.
Such a tension member may be a strand-like member or a belt-like member, but in order to facilitate cutting, a plurality of low-stretch high-strength fibers are aligned (straight without twisting / knitting). Yarns can be suitably used.
The tension member 13 exists over the entirety of the impact load relaxation rope 1 from one end to the other end.

Further, the tension member 13 is formed by aligning a plurality of low-stretch high-strength fibers as a base yarn (straight without twisting and weaving). It may be formed in a mixed manner.
The yarn constituting the tension member 13 is a low elongation fiber relative to the yarn used for the inner layer and the outer layer, and the elongation of the yarn of the low elongation fiber is the inner layer and the outer layer. When the elongation is in the range of 30% to 40%, for example, it is preferably in the range of 3% to 10%.
Examples of the material constituting the tension member 13 include meta-aramid fibers, para-aramid fibers (Kevlar (registered trademark) and Technora (registered trademark)), high-strength polyarylate fibers (Vectran (registered trademark)), ultra-high Low-stretch high-tensile fibers such as molecular weight polyethylene fibers (Dyneema (registered trademark)) can be used. Technora's elongation is 3% to 5%.

As described above, the tension member 13 is a member that is cut when a tensile load of a predetermined value or more is applied. For example, a member that is cut when about 2 to 3 kN is applied as a drop impact load is preferable. Can be used for In order to prevent the occurrence of problems such as being cut when the impact load relaxation rope 1 is caught by a structure or the like during the movement of the worker, for example, it should be prevented from being cut by a drop impact load of about 1.5 kN. Good.
As described above, the impact load relaxation rope 1 is sewn at both ends and is provided with eye portions 1a and 1b that are ring-shaped portions. However, if the tension member 13 is sewn with a sewing machine during sewing, the strength decreases. Therefore, it is desirable to avoid the seam in the arrangement position of the tension member 13. Therefore, in the example of FIG. 2, the tension member 13 is disposed at a position directly above (0 ° position) in the drawing.

Next, the effect | action of said impact load relaxation rope is demonstrated.
In the first embodiment, the tension member 13 is disposed between the inner layer 11 and the outer layer 12 in the impact load relaxation rope 1, and the impact load relaxation rope 1 is configured when a predetermined load is applied to the impact load relaxation rope 1. Both the inner layer 11 and the outer layer 12 are elongated. At this time, since the tension member 13 is also disposed between the inner layer and the outer layer and is pressed by the outer surface of the inner layer and the outer surface of the outer layer, the tension member 13 extends simultaneously with the expansion of the inner layer 11 and the outer layer 12.
However, since the tension member 13 has a lower elongation than the inner layer 11 and the outer layer 12, a large drop impact load is applied at the time of dropping, and as a result, the tension member 13 is cut when a tensile load of a predetermined value or more acts.
Thus, the fall energy is absorbed by the tension member 13 being cut, but the fall energy absorption by the cut can absorb the impact in an extremely short time unlike the fall energy absorption by “elongation”. . Therefore, the falling energy that is not sufficiently absorbed only by extending the inner layer 11 can be absorbed by cutting the tension member 13.

  As described above, according to the impact load relaxation rope according to the first embodiment, the elongation is lower than that of the inner layer 11 and the outer layer 12, a large drop impact load is applied, and a tensile load of a predetermined value or more acts. Since the tension member 13 to be applied is arranged between the inner layer 11 and the outer layer 12, it is possible to sufficiently absorb the short-time drop energy that acts during the fall.

Embodiment 2. FIG.
In the first embodiment, the tension member 13 is disposed between the inner layer 11 and the outer layer 12, but in order to increase the frictional force between the tension member 13, the inner layer 11 and the outer layer 12, tension is applied. The member 13 may be coated with a resin.
Examples of the resin coated on the tension member 13 include rubber resins such as chloroprene and urethane.
The tension member 13 is coated with resin in whole or in part.

In this way, by coating the tension member 13 with the resin to increase the frictional force between the tension member 13 and the inner layer 11 and the outer layer 12, when the large drop impact load is applied at the time of dropping, the tension member 13 is It becomes possible to cut not only at the places but also at a plurality of places in the longitudinal direction.
That is, when the tension member 13 is simply disposed between the inner layer 11 and the outer layer 12 and the frictional force between the inner layer 11 and the outer layer 12 is low, when the tension member 13 is cut at one place, the tension member 13 is no longer used. Since the tensile load with respect to 13 becomes substantially zero, it is not cut at a plurality of locations.
However, if the frictional force between the inner layer 11 and the outer layer 12 is high, a tensile load is applied from a portion that has already been cut. If the tensile load is higher than a predetermined value, the portion may be further cut. is there.

Further, the friction force may be increased by adhering the tension member 13 to at least one of the inner layer 11 and the outer layer 12. For example, at the time of manufacture, the tension member 13 having an outer periphery coated with an adhesive is disposed between the inner layer 11 and the outer layer 12 so that the tension member 13 is bonded to the inner layer 11 and the outer layer 12.
In this case, for the same reason, the tension member 13 can be cut at a plurality of locations in the longitudinal direction, and the maximum value of the drop impact load can be reduced.

Embodiment 3 FIG.
Although the tension member 13 is disposed between the inner layer 11 and the outer layer 12 in the first embodiment, a plurality of tension members 13 having different elongations are disposed between the inner layer 11 and the outer layer 12. You may be allowed to.
Needless to say, a plurality of tension members 13 having the same elongation may be disposed between the inner layer 11 and the outer layer 12.

  For example, as a method of forming a plurality of tension members 13 having different elongations, if the number of raw yarns (low elongation high tensile fibers) constituting each tension member 13 is different, the elongation is A plurality of different tension members 13 are formed. The number of raw yarns constituting each tension member 13 can be changed within a range of 1 to 15, for example.

  Similarly, if the twisting and knitting methods of the yarns (low-tensile high-tensile fibers) constituting each tension member 13 are different, a plurality of tension members 13 having different elongations are formed. it can. For example, a method in which one tension member 13 is “aligned” and another tension member 13 is “twisted and twisted” can be considered. Further, it is also conceivable to use a tension member 13 having a “three-strand rope shape” and another tension member 13 having a “triple rope shape” to vary the elongation.

  Moreover, the tension member 13 of the different tension | tensile_strength can be formed by making the material of the raw yarn (low-tensile high tension fiber) which comprises each tension member 13 differ. For example, one tension member 13 may be formed of meta-aramid fibers, and the other tension member 13 may be formed of para-aramid fibers (Kevlar or Technora).

  As described above, when a plurality of tension members 13 having different elongations are arranged between the inner layer 11 and the outer layer 12, when a large drop impact load is applied, the tension members 13 having a lower elongation are sequentially cut. Therefore, the fall energy can be absorbed at a plurality of locations. For this reason, the effect which can reduce more efficiently the maximum value of a drop impact load like the said Embodiment 2 is acquired.

When a plurality of tension members 13 having different elongations are arranged between the inner layer 11 and the outer layer 12, the tension members 13 are not sewn with a sewing machine when the eye portions 1a and 1b that are ring-shaped portions are provided. It is desirable to arrange it at a position.
For example, when two tension members 13 are arranged between the inner layer 11 and the outer layer 12, as shown in FIG. 4, one tension member 13 is disposed at a position directly above (0 ° position), and If the other tension member 13 is disposed between 60 ° and 90 °, these are prevented from being sewn by the sewing machine. If it is placed at 180 °, it may be sewn with a sewing machine.
In addition, when three or four tension members 13 are inserted, a method of arranging these tension members 13 evenly or concentrating them all between 60 ° and 90 ° is conceivable. FIG. 5 shows an example in which four tension members 13 are arranged.

Embodiment 4 FIG.
In the first to third embodiments, the tension member 13 is arranged between the inner layer 11 and the outer layer 12, but four tension members 13 are arranged between the inner layer 11 and the outer layer 12. A strand that includes a plurality of strands 11a forming the inner layer 11 or one or more strands in the plurality of strands 11a forming the inner layer 11 in part of a tension member having a lower elongation than the other strands Alternatively, the strand 11a may be made of only a tension member having a lower elongation than the other strands.
Here, the strand 11a partially including a tension member having a lower elongation than the other strands means that any one of the yarns constituting the strand is a tension member having a lower elongation than the other yarns. Including that.
Further, in a plurality of strands forming the inner layer, all or a part of the yarns constituting the strands may be replaced with the other strands, the yarns of the other strands, or the yarns constituting the other strands. A tension member having a lower elongation than yarns or other raw yarns may be used.
The tension members are all the same as the tension members shown in the first to third embodiments.
That is, you may make it form the inner layer 11 using the strand 11a and a tension member.
FIG. 6 shows an example in which one strand of the 16 strands 11a forming the inner layer 11 is a strand 11a including the tension member 14 as a part thereof.
In this case, when a large drop impact load is applied at the time of dropping, not only the inner layer 11 is stretched but also the tension member 14 forming the inner layer 11 is cut. Can be reduced.

Embodiment 5. FIG.
In the fourth embodiment, four tension members 13 are arranged between the inner layer 11 and the outer layer 12. However, the inner layer is formed around the core material 15 arranged in the center and the core material. The core material 15 is composed of a core tape or a core strand, and the whole or a part of the core material 15 has a lower degree of elongation than the plurality of strands. It may be a tension member.
In addition, the whole or a part of the core yarn arranged in the center of the inner layer is tensioned at a lower elongation than the other strands, the yarns of the other strands, or the yarn yarns constituting the other strands. It is good also as a member.
The tension members are all the same as the tension members shown in the first to third embodiments, and the structure of the core tape or the core strand is the same as described above.
FIG. 7 particularly shows an example in which the core material 15 disposed in the center of the inner layer is formed of a tension member having a lower elongation than a plurality of strands forming the inner layer.
In this case, when a large drop impact load is applied at the time of dropping, not only the inner layer 11 is stretched, but also the core material 15 constituting the tension member is cut, so that the time during which the impact load acts is lengthened and the maximum impact load is increased. Can be reduced.
FIG. 8 shows an example in which one strand of the plurality of strands 11a is a strand 11a including a tension member 14, and the entire core material 15 is formed of a tension member having a low elongation. Yes.
In this case, when a large drop impact load is applied at the time of dropping, not only the inner layer 11 extends but also the tension member of the strand 11a constituting the inner layer 11 is cut and the tension member constituting the core material 15 is also cut. Thus, the amount of fall energy absorbed can be increased.

  Next, an embodiment in which the impact load relaxation rope 1 described above is applied as a lanyard will be described.

FIG. 1 is a side view showing a lanyard using an impact load relaxation rope according to an embodiment of the present invention.
In FIG. 1, 1 is an impact load relaxation rope, and 1 a and 1 b are eye portions that are ring-shaped portions formed at both ends of the impact load relaxation rope 1.
Reference numeral 2 denotes a connecting bracket 2 which is attached to the eye 1a of the impact load relaxation rope 1 and is not shown in a safety band (body belt type safety band, harness type safety band, etc.) worn by the operator. It is the 1st connecting member connected with a connecting metal fitting (for example, metal hooks).
Although FIG. 1 shows an example in which the connecting metal fitting 2 is a ring-shaped metal fitting, the present invention is not limited to this. For example, the connecting metal fitting 2 may be a metal hook or the like.

Reference numeral 3 denotes a connection fitting, which is attached to the eye portion 1b of the impact load relaxation rope 1 and connected to a fall prevention support portion (for example, a master rope, a solid structure column, etc.) provided in the work place. A second connecting member.
In FIG. 1, an example in which the connection fitting 3 is a metal hook is shown, but the hook is not limited to such a hook as long as it is a member that can be connected to the support portion for preventing fall.

Next, the operation of the lanyard including the rope will be described.
When an operator performs work at a high place, the worker connects the lanyard fitting 2 with a fitting of a safety band (not shown) that is worn.
In addition, the lanyard coupling fitting 3 is coupled to a fall prevention support in the workplace. Thereby, a worker's body will be in the state connected with structure etc. via the lanyard.

When a situation occurs such that the operator steps off the foot from the scaffolding or the like of the work place in a state where the connection is completed, a large drop impact load is applied to the impact load relaxation rope 1.
At this time, the drop impact load at the time of dropping is absorbed by the inner layer 11 of the shock load relaxation rope 1, but the drop energy due to the elongation of the inner layer 11 is absorbed over a long time to some extent, and is extremely short. In time, it does not absorb fall energy.
On the other hand, the action time of the drop impact load applied at the time of dropping is a very short time of about 0.3 to 0.4 seconds, and the work can be performed only by absorbing and relaxing the drop impact load due to the extension of the inner layer 11. The impact load acting on the person may not be sufficiently reduced.

However, in the impact load relaxation rope 1 in this embodiment, the tension member 13 is arranged between the inner layer 11 and the outer layer 12, and the tension member 13 has a lower degree of elongation than the inner layer 11 and the outer layer 12, so that when it is dropped When a large drop impact load is generated and a tensile load of a predetermined value or more is applied, this is cut while the inner layer 11 and the outer layer 12 are extended.
As the tension member 13 is cut, the rate at which the inner layer 11 and the outer layer 12 extend is suppressed. As a result, the fall energy is absorbed. The fall energy absorbed by such a cut is absorbed by the fall energy. Unlike the case of only, it is possible to absorb the impact in a very short time as a whole.
For this reason, the falling energy that is not sufficiently absorbed only by extending the inner layer 11 is absorbed by the cutting of the tension member 13.

As described above, the impact load relaxation rope 1 in this embodiment has a lower elongation than the inner layer 11 and the outer layer 12, and the tension member 13 that is cut by a tensile load greater than or equal to a predetermined value due to a large drop impact load when dropped. Since it arrange | positions between the inner layer 11 and the outer layer 12, there exists an effect which can fully absorb the fall energy which arises in a short time.
That is, since the maximum value of the drop impact load applied to the impact load relaxation rope 1 is reduced, when a large drop impact load is generated at the time of dropping, it can be applied to, for example, a worker having a large weight.

The length of the impact load relaxation rope is 1.5 m, and the tension member is formed of para-aramid fiber (technola) with low elongation as a raw yarn. This is a total of 2 at predetermined locations between the inner layer 11 and the outer layer 12. What was distributed was created and the elongation due to load was measured.
The material of the outer layer of the impact load relaxation rope is nylon, and its breaking elongation is 94%. The material of the inner layer of the impact load relaxation rope is nylon and its breaking elongation is 63%. The material of the tension member is low-stretch para-aramid fiber (Technola), and its breaking elongation is 5%.
FIG. 9 is a graph showing a load-elongation curve when the impact load relaxation rope 1 is subjected to a tensile test.
FIG. 9A is a graph showing a load elongation curve of the impact load relaxation rope 1 including only the inner layer 11 and the outer layer 12 in which the tension member 13 is not used, and FIG. 13 is a graph showing a load elongation curve of the impact load relaxation rope 1 arranged between the inner layer 11 and the outer layer 12.

As shown in FIG. 9A, when the tension member is not arranged, the elongation is 20%.
A sharp rise of the curve is seen at a point exceeding.
On the other hand, when the tension member is arranged, as shown in FIG. 9B, the elongation rate is small, but the rise of the drop impact load tends to be quick, and the drop impact load is 2 to 3 kN. In this range, it is recognized that the tension member 13 is cut. Thereafter, the rise of the drop impact load is small until the elongation reaches 35%, and it is recognized that the rise of the static load is accelerated when the elongation exceeds 35%.
Therefore, the elongation speed of the rope is suppressed until the elongation rate exceeds 35%, and the load does not increase rapidly. If this is used for a lanyard, the burden on the wearer is reduced.

One end of a lanyard using the same impact load relaxation rope 1 of Example 1 was hooked on a load meter, and the other end was fixed to a torso having a mass of 85 kg. And the impact load value when the said torso was dropped 1.7m was measured with the load meter.
FIG. 10 is a graph showing the time-drop impact load applied to the impact load relaxation rope 1 which is not provided with the tension member 13, that is, the inner layer 11 and the outer layer 12, and FIG. It is the graph which showed the time-drop impact load added to the impact load relaxation rope 1 distribute | arranged between the inner layer 11 and the outer layer 12. FIG.

When the tension member 13 is not arranged, the drop impact load applied to the impact load relaxation rope 1 represents a parabola as shown in FIG. 10, and the maximum load exceeds 8 kN.
On the other hand, when the tension member 13 is disposed, the drop impact load applied to the impact load relaxation rope 1 is approximately 0.07 seconds after the load is applied to the load cell as shown in FIG. The falling energy is absorbed by the member 13 being cut. As a result, the maximum value of the drop impact load is reduced to 8 kN or less.

12 to 14 show the results of the drop impact test performed on the impact load relaxation rope. The difference from Example 2 is that a plurality of tension members are arranged between the inner layer and the outer layer (in the longitudinal direction). It is that.
12 and 13 are graphs showing the time-drop impact load applied to the impact load relaxation rope when two tension members 13 are arranged in the longitudinal direction between 60 ° and 90 °.
FIG. 12 shows that when about 0.05 seconds have passed since the torso fell, the first tension member was cut, and then about 0.07 seconds passed after the torso dropped. The second tension member is cut and the fall energy is absorbed. As a result, the maximum value of the drop impact load is reduced to 8 kN or less.
Note that the waveform shown in FIG. 12 is the same as the waveform generated when two tension members are cut in the longitudinal direction when one tension member is provided.
In FIG. 13, after about 0.05 seconds have passed since the torso fell, the tension member is cut at three or more locations, and the dropping energy is absorbed. As a result, the maximum value of the drop impact load is reduced to 7 kN or less.
Next, a graph showing the time-drop impact load applied to an impact load relaxation rope having three tension members arranged in the longitudinal direction.
In FIG. 14, after about 0.04 seconds have passed since the torso dropped, it was cut at six or more locations, and the falling energy was absorbed. As a result, the maximum value of the drop impact load is reduced to 5 kN or less.

  As described above, the maximum value of the drop impact load in the case of FIG. 14 with the largest number of cuts of the tension member is the smallest. That is, as is apparent from FIGS. 12 to 14, it is recognized that the greater the number of cuts of the tension member, the more the number of drops of energy absorbed, and thus the maximum value of the drop impact load is reduced.

DESCRIPTION OF SYMBOLS 1 Impact load relaxation rope 1a, 1b Eye part 2 Connection metal fitting (1st connection member)
3 Connecting bracket (second connecting member)
4,5 Fastener 11 Inner layer 11a Strand 12 Outer layer 12a Strand 13, 14 Tension member 15 Core material

Claims (10)

An inner layer that is a rope body formed by weaving or twisting a plurality of strands and an outer layer that covers the inner layer, and has a lower elongation than the inner layer and the outer layer, and a tensile load acts on the inner layer. And a tension member that is cut with a tensile load of a predetermined value or more while the outer layer is extended, is disposed between the inner layer and the outer layer,
The impact load relaxation rope, wherein the tension member is coated with a resin that increases a frictional force between the inner layer and the outer layer. An inner layer that is a rope body formed by weaving or twisting a plurality of strands and an outer layer that covers the inner layer, and has a lower elongation than the inner layer and the outer layer, and a tensile load acts on the inner layer. And a tension member that is cut with a tensile load of a predetermined value or more while the outer layer is extended, is disposed between the inner layer and the outer layer,
The tension load relaxation rope, wherein the tension member is bonded to at least one of the inner layer and the outer layer. When there are a plurality of tension members and the position of one tension member is 0 ° in the sectional view of the impact load relaxation rope, the central angle formed with the other tension members is 60 ° to 90 °. The impact load relaxation rope according to claim 1 or 2, wherein all of the tension members are arranged in a sector-shaped region.   The impact load relaxation rope according to any one of claims 1 to 3, wherein a plurality of tension members having different elongations are arranged between the inner layer and the outer layer.   The impact load relaxation rope according to claim 4, wherein the number of raw yarns constituting each tension member is different.   The impact load relaxation rope according to claim 4, wherein a method of knitting or twisting the raw yarn constituting each tension member is different.   The impact load relaxation rope according to claim 4, wherein the material of the yarn constituting each tension member is different.   A tension member having a lower elongation than other strands is used for all or part of a plurality of strands forming the inner layer or all or part of the core material. The impact load relaxation rope according to any one of items 7 to 9.   A tension member having a lower elongation than other strands is used for all or some of the plurality of strands forming the inner layer or all or some of the core yarns of the core material. The impact load relaxation rope according to any one of claims 1 to 7. The impact load relaxation rope according to any one of claims 1 to 9,
A first connecting member that connects one end of the impact load relaxation rope to a safety belt worn by an operator;
A lanyard comprising: a second connecting member that connects the other end of the impact load relaxation rope to a support portion for preventing fall in a work place.

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