A Type of High-Strength Low-Elongation Static Rope

Abstract

This static rope pertains to the field of rescue equipment. It is a high-strength, low-elongation static rope and its braiding method. The high-strength, low-elongation static rope comprises a core and a sheath outside the core. The core is formed by three strands braided in an equilateral triangular parallel arrangement. Each strand is braided by an 8-carrier, 12-carrier, or 16-carrier braiding machine. The core of the invention utilizes three strands to form a stable equilateral structure, effectively dispersing external forces applied to the static rope, providing a breaking strength far exceeding the average destructive force, maintaining a compact structure, offering more stable control, and preventing sheath slippage.

This static rope can be perfectly matched with equipment conforming to the EN 341:2011 standard, offering better braking force and stable speed under high-load operating conditions. Through pre-stretching and post-treatment, the strength is increased while the fiber elongation is reduced, meeting the requirements of high strength and low elongation.

Background

Static ropes, based on their characteristics of high strength and low elongation, are mainly used in caving and rescue equipment, as well as for protection ropes in rappelling and climbing gyms. Traditional safety ropes often only have single-braid or double-braid structures, suffering from issues like insufficient strength and excessive elongation, which cannot meet the requirements for stable load-bearing under heavy loads.

Technical Solution

[0004] A high-strength, low-elongation static rope includes a core and a sheath outside the core. The core is formed by three strands braided in an equilateral triangular parallel arrangement. Each strand is braided by an 8-carrier, 12-carrier, or 16-carrier braiding machine.

[0005] Based on the above solution, the core and sheath are made of nylon, polyester, or aramid.

[0006] The braiding method for the aforementioned high-strength, low-elongation static rope includes:

[0007] S1. Combining and twisting multiple yarns into twisted yarn for the core;

[0008] S2. Combining and twisting multiple yarns into twisted yarn for the sheath;
[0009] S3. Braiding the twisted yarn of the core into strands for the core using an 8-carrier, 12-carrier, or 16-carrier braiding machine;
[0010] S4. Braiding three strands in an equilateral triangular parallel arrangement to obtain the core;
[0011] S5. Pre-stretching the core;
[0012] S6. Sheathing the core by braiding multiple twisted yarns of the sheath around it using a 24-carrier, 32-carrier, or 48-carrier braiding machine to form the sheath;
[0013] S7. Applying hot-air blowing or infrared drying for shaping to the entire rope (core and sheath).

[0014] Based on the above solution, in step S5, the pre-stretching draw ratio is 105%-180%.

[0015] Preferably, in step S5, the multiple strands are stretched simultaneously.

[0016] Preferably, the treatment temperature for hot-air blowing or infrared drying is 100°C-150°C, and the treatment time is 3min-20min.

[0017] Preferably, the diameter of the high-strength, low-elongation static rope is 8.5-16mm, the diameter proportion of the sheath is 25%-55%, the number of core yarn ends is 10-70, and the number of sheath yarn ends is 10-70.

[0018] The beneficial effects are: The core uses three strands to form a stable equilateral structure, effectively dispersing external forces applied to the static rope, providing a breaking strength far exceeding the average destructive force, maintaining a compact structure, offering more stable control, and avoiding sheath slippage. It can be perfectly matched with equipment conforming to the EN 341:2011 standard, offering better braking force and stable speed under high-load operating conditions. Through pre-stretching and post-treatment, the strength is increased while the fiber elongation is reduced, meeting the requirements of high strength and low elongation.

Implementation Mode

[0025] A high-strength, low-elongation static rope includes a core and a sheath outside the core. The core is formed by three strands braided in an equilateral triangular parallel arrangement. Each strand is braided by an 8-carrier, 12-carrier, or 16-carrier braiding machine. The core and sheath are made of nylon, polyester, or aramid.

[0026] The braiding method for the aforementioned high-strength, low-elongation static rope includes:

[0027] S1. Combining and twisting multiple yarns into twisted yarn for the core (1);
[0028] S2. Combining and twisting multiple yarns into twisted yarn for the sheath (2);
[0029] S3. Braiding the twisted yarn of the core (1) into small cords (strands for the core) using an 8-carrier, 12-carrier, or 16-carrier braiding machine with an 8-carrier pattern weave;
[0030] S4. Braiding three strands in an equilateral triangular parallel arrangement to obtain the core (1); Utilizing three core strands, controlling the input tension of the core strands into the machine to keep the tension of the three core strands consistent, forming a stable equilateral triangular structure. When subjected to external impact, all three sides bear the force simultaneously, significantly increasing the strength compared to ordinary safety ropes without an equilateral stable structure. Meanwhile, the central cavity of the tri-equilateral stable structure has a uniform gap structure. When impacted, it can effectively disperse force and absorb impact energy, thereby meeting the requirements of relevant standards for impact force and number of falls.

[0031] S5. Pre-stretching the core with a draw ratio of 105%-180%. By applying pre-tension treatment to the core (1), surface stress is removed, increasing strength while reducing fiber elongation, meeting the requirements of high strength and low elongation. During pre-stretching, the three strands are stretched simultaneously, which not only improves the processing efficiency of the strands but also ensures the same draw ratio and effect for the multiple strands, maintaining consistent tension in each strand. This ensures that each strand bears the same force during the use of the static rope, improving its performance and service life;
[0032] S6. Sheathing the core by braiding multiple twisted yarns of the sheath (2) around it using a 24-carrier, 32-carrier, or 48-carrier braiding machine to form the sheath;
[0033] S7. Applying hot-air blowing or infrared drying for shaping to the entire rope (core and sheath). The treatment temperature for hot-air blowing or infrared drying is 100°C~150°C, and the treatment time is 3min-20min.

[0034] The diameter of the high-strength, low-elongation static rope is 8.5-16mm, the diameter proportion of the sheath (2) is 25%-55%, the number of core yarn ends is 10-70, and the number of sheath yarn ends is 10-70.

[0035] According to standard EN 1891:1998 "Personal protective equipment for the prevention of falls from a height - Low stretch kernmantel ropes", the static rope from the embodiment and an existing ordinary static rope were subjected to performance tests under the conditions of a first impact force of 5.1 kN, number of falls 7, and static strength of 30 kN. The test results obtained are shown in the table below.