JPH08311787A - Safety belt rope for absorbing shock - Google Patents

Abstract

PURPOSE: To improve the operating efficiency and reduce the cost by eliminating a belt type shock absorber. CONSTITUTION: This safety belt rope for absorbing shock is obtained by using high-elongation fibers in a yarn in an inner layer 1 of each strand constituting a three strand rope, using nylon fibers in a yarn in an outer layer 2, producing the rope to constitute a nearly equal elongation in the inner layer 1 and outer layer 2 under 400-500kgf load in the case of 10-12mm diameter and 700-800kgf load in the case of 14-16mm diameter. Thereby, the rope itself is capable of absorbing and relaxing the drop impact load, and the installation of a conventional belt type shock absorber is not required.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present application relates to a rope of a safety belt used for the purpose of preventing a fall when working at height.

[0002]

2. Description of the Related Art Safety belts are always used in construction work, electric work, and other high-altitude work, but if a fall occurs, there is a concern that a so-called secondary disaster will occur depending on the usage situation. In some cases, The safety belt is generally composed of a belt portion that is fastened to the waist and a rope portion that connects the belt portion and the structure. The safety belt prevents the human body from falling by locking the hook at the tip of the rope portion. . The length of the rope part is usually 1.5M, and if the hook locking position is near the waist, it will be prevented from falling due to the rope length falling, and the hook will be locked at or below the foot. If a crash occurs, a maximum fall distance of 3M will occur, and the human body fall prevention load at that time will be close to 1000 kgf. When an impact load of 1000 kgf was concentrated and applied to one point on the waist, internal organs could be injured and fractures could have occurred. Also, depending on the weight of the user, it is necessary to consider the same impact load even if the fall distance is short. Therefore, a secondary shock is prevented by using a shock absorber that absorbs and alleviates a drop impact force. Like the belt part, the shock absorber is a narrow woven belt made of synthetic fiber, folded back in the length direction, stitched the overlapped part with a sewing machine and stored it in a capsule etc. Apply a drop impact load in the direction to dissociate the yarn,
Therefore, the shock is absorbed. The arrangement of the shock absorber is between the hook and the rope, at a predetermined position between the ropes, between the rope portion and the belt portion, and the like. Impact load is 500kgf at maximum due to the use of shock absorber
Although it is possible to prevent the occurrence of secondary disasters by suppressing it to the following level, it is important to interpose a shock absorber with a certain size between the human body and the structure, that is, at any part of the safety belt. Either way, it was awkward. For example, when it is placed between the hook and the rope, the hook is hung every time the working position moves, which makes the hook difficult to handle, and the one having a certain size at the base of the hook always swings. In addition, the hook is locked on the ring of the belt portion when walking, but at that time it swings and hits the upper leg portion, which is unpleasant. Also, because it is stored in a capsule, etc., it cannot be inspected from the outside, for example, when welding sparks fly and melting is progressing in the capsule,
It is also possible that the performance and effects as designed cannot be obtained.
Further, in manufacturing shock absorbers, many parts are manually processed by sewing multiple threads with a sewing machine, folding and storing in a capsule, and the cost ratio in the safety belt is also high.

[0003]

In order to solve the problems of the conventional products as described above, the present application discloses a safety belt having a function of absorbing and mitigating a shock load at the time of dropping without disposing a shock absorber. is there. Of the belt portion and the rope portion that constitute the safety belt, if the rope has a shock absorbing function, the same effect can be obtained without providing a separate shock absorber. Generally, a nylon rope with three strands is used for the safety belt, and the elongation of the nylon fiber, even if the shock absorber is not installed,
A certain cushioning effect can be obtained by the elongation of the rope and the construction of the rope. Elongation due to the composition of the rope means that the composition of the rope usually used for the safety belt is about 1200 denier of the filament bundled with the nylon raw yarn.
The main yarn is twisted to form a ring yarn, and the three yarns are twisted to form a rope yarn. Since both of these yarns are twisted, they are in a contracted state in the length direction and naturally expand when a load is applied. About 20 rope yarns are twisted to form a strand, and three ropes are twisted to form a rope. The strand is composed of an inner layer and an outer layer,
In general, the outer layer, which further spirally surrounds the twisted inner layer, is structurally longer. That is, when a load is applied to such a rope strand, it acts on both the inner layer and the outer layer in the initial stage, and in the next stage, the rate of the inner layer having a short dimension increases. Therefore, when a high load is applied, the limit of the inner layer determines the strength characteristics of the rope even if there is still room in the outer layer. Since the strands having the above-described structure and the final three-stage twisting stage are naturally twisted together, elongation under load can be expected. As described above, some elongation can be obtained even with a rope composed only of nylon fiber, but in the present application, in order to have a higher shock absorbing function on the characteristics of this nylon fiber,
A high elongation fiber is used for the inner layer 1 of each strand 3 of the rope, and the outer layer 2 is composed of nylon fiber. That is, the inner layer 1 and the outer layer 2 of the strand 3 are made of different materials, and the difference in the structural length is adjusted by the elongations thereof so that they are synchronized with each other. In addition to further increasing the strength limit of the rope, the rope having high elongation is obtained. The high elongation fiber used for the inner layer 1 is, for example, highly stretchable polyester fiber, and the outer layer
Set the one that has a greater elongation than the nylon fiber used for 2.

[0004]

[Operation] The operation of the rope of the present application when a high load is applied is described. When a high impact load for stopping a fall is applied, the three strands constituting the rope are stretched and the impact force is absorbed. It (First stage) In the next stage, a load is applied to each strand 3, the twist of the strand 3 itself extends, and the inner layer 1 having a shorter constituent length than the outer layer 2 first bears the load, and the inner layer 1 rope yarn
The twist of 4 is extended. Similarly, the twist of the ring yarn 5 also stretches, and the high shrinkability of the polyester fiber itself is exhibited.
(Second stage) In parallel with the progress of the second stage, the twist of the outer layer 2 made of nylon fiber and the elongation of the rope yarn 4 and the ring yarn 5 are progressing, but the constituent length is longer than that of the inner layer 1. Is long and is in a relaxed state, so there is still room for elongation even when the inner layer 1 yarn reaches its elongation limit.
・ By using a highly stretchable polyester fiber for the inner layer 1 and setting the elongations of both the inner and outer layers to be approximately the same, the entire strand bears the impact load. (Third stage) As described above, by using the highly elastic fiber for the inner layer 1 of each strand and synchronizing the elongation under load with the outer layer 2, high strength and low initial shock absorption load value, You get a rope suitable for the safety belt.

[0005]

EXAMPLE An example of the present application shows a rope composed of three strands. The inner layer 1 of each strand is made of high elongation polyester fiber and the outer layer 2 is made of nylon fiber. The high elongation polyester fiber used for the inner layer 1 has an intrinsic viscosity of 0.7 or more, a strength of 5 g / d or more, and a boiling water shrinkage ratio of 30.
%, And the thermal stress value is 0.4 g / d or more. In order to synchronize the elongations of the inner layer 1 and the outer layer 2 at about 1000 kgf, which is a general crash hold load when using a safety belt, experiments were performed by changing the composition and twist. The optimum construction obtained as a result is, for example, in the construction of a rope of 16 mmφ, the inner layer 1 is 1000 denier of high elongation polyester × 4 × 3 × 5, and the outer layer 2 is nylon 126.
It is 0 denier × 3 × 4 × 14. In an experiment using a 16 mmφ rope, the impact load when a 100 kf sandbag was dropped for 2.5 m was about 800 kg, which was proved to be more effective than the conventional value of nearly 1 ton. In addition, as a result of obtaining the same best configuration with a rope of 10 mmφ which is generally used for a safety belt, a value sufficiently lower than 500 kgf was obtained.
Fig. 2 shows the impact load waveform when 75 kg was held with a 10 mmφ rope at a drop distance of 1.5 m. The solid line indicates the waveform of the rope of the present application, and the broken line indicates the waveform of the conventional inner and outer layer nylon fibers. In the case of the present application, the inner and outer layers are synchronized 400
The waveform becomes smoother from around kg, and the maximum point is around 500 kgf. On the other hand, the conventional rope has a load of more than 600 kgf, which exceeds 600 kgf. In the case of the rope of the present invention, the inner layer and outer layer are synchronized around 400 kgf, and the outer layer with low elongation mainly acts as resistance to increase the load, but the degree is low, and the conventional rope has 500 kgf.
In the vicinity, the inner layer is in a so-called bottomed state, and the elongation of the outer layer cannot be obtained, so that the load increases.

[0006]

As described above, by using the invention of the present application, it is possible to prevent the fall of a fall under a low impact load that does not damage the human body, without using a shock absorber, in a safety belt for working in high places. It is a thing. Therefore, not only the workability at the time of using the safety belt is increased, but also the economical effect can be obtained by not using the shock absorber.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a rope of the present application.

FIG. 2 is a waveform diagram of a drop impact load according to the present application.

[Explanation of symbols]

 1 Inner layer 2 Outer layer 3 Strand 4 Rope yarn 5 Ring yarn

Claims (1)

[Claims] 1. A high-stretch fiber is used for the inner layer 1 yarn of each strand of the three-strand rope, and a nylon fiber is used for the outer layer 2 yarn.
0-500kgf, 700-800kg for 14-16mm diameter
f A shock-absorbing safety rope, characterized in that the inner layer 1 and outer layer 2 under load have substantially the same elongation.