Cut resistant jacket for ropes, webbing, straps, inflatables and the like

Abstract

 This invention is a cut resistant article comprising a cut resistant jacket surrounding a less cut resistant member. The jacket comprises a fabric of yarn and the yarn consists essentially of a high strength, longitudinal strand having a tensile strength of at least 1 GPa. The strand is wrapped with another fiber or the same fiber.

Description

BACKGROUND OF THE INVENTION

[0001] This invention relates to a cut resistant jacket for ropes, webbing, straps, inflatables and the like, more particularly a cut resistant article comprising a cut resistant jacket surrounding a less cut resistant member where the jacket comprises a fabric of a yarn and the yarn consists essentially of a high strength, longitudinal strand having a tensile strength of at least 1 GPa and the strand is wrapped with a fibre.

[0002] It is known to make cut resistant fabric for gloves used for safety in the meat cutting industry. For example see U.S. Patent 4 470 251, U.S. Patent 4 384 449 and U.S. Patent 4 004 295 all hereby incorporated by reference. It is also known to make a composite line containing two different filamentary materials in the form of a core and a jacket of different tensile strengths and elongations as in U.S. Patent 4 321 854 hereby incorporated by reference. It is also known to make composite strand, cables, yarns, ropes, textiles, filaments and the like in other prior U.S. patents not cited herein.

[0003] By ultrahigh molecular weight is meant 300,000 to 7,000,000. Normal molecular weight is then below 300,000.

SUMMARY OF THE INVENTION

[0004] This invention is a cut resistant article comprising a cut resistant jacket surrounding a less cut resistant member. The jacket comprises a fabric of yarn. The yarn consists essentially of a high strength, longitudinal strand having a tensile strength of at least 1 GPa. More than one strand can be used. This strand (or strands) is wrapped with a fiber. The fiber may be the same or different than the longitudinal yarn.

[0005] It is preferred that the fiber wrapped around the strand also have a tensile strength of at least 1 GPa.

[0006] The less cut resistant member can be selected from the group consisting of rope, webbing, strap, hose and inflatable structures.

[0007] The core strand fiber of the rope, webbing, strap or inflatable structures could be fiber of nylon, polyester, polypropylene, polyethylene, aramid, ultrahigh molecular weight high strength polyethylene or any other known fiber for the use.

[0008] The inflatable structure would be a less cut resistant layer having the fabric of this invention as a jacket or outer layer. The strand used for the fiber in the jacket may be selected from the group consisting of an aramid, ultrahigh molecular weight polyolefin, carbon, metal, fiber glass and combinations thereof. The fiber used to wrap the longitudinal strand (or strands) can be selected from the group consisting of an aramid fiber, ultrahigh molecular weight polyolefin fiber, carbon fiber, metal fiber, polyamide fiber, polyester fiber, normal molecular weight polyolefin fiber, fiber glass, polyacrylic fiber and combinations thereof. When the fiber wrapping is a high strength fiber having strength over 1 GPa, the preferred fiber wrapping is selected from the group consisting of aramid fiber, ultra high molecular weight polyolefin fiber, carbon fiber, metal fiber, fiber glass and combinations thereof.

[0009] The polyolefin fiber of this invention can be ultrahigh molecular weight polyethylene or polypropylene, preferably polyethylene, commercial examples are Spectra® 900 or Spectra® 1000.

[0010] The fiber wrapping can also be a blend of a lower strength fiber with the high strength fiber. Such lower strength fiber can be selected from the group consisting of polyamide, polyester, fiber glass, polyacrylic fiber and combinations thereof.

[0011] The article of this invention can also have more than one jacket surrounding the less cut resistant member.

[0012] In another embodiment, the article of this invention has a material present in the interstices of the fabric of the jacket to bond the yarn of the fabric to adjacent yarn of the fabric thereby increasing penetration resistance of the jacket. The material used in the interstices can be any elastomer, preferably a thermoplastic rubber and more preferably a material selected from the group consisting of polyurethane, polyethylene and polyvinyl chloride.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Yarns for Jacket Fabric

[0013] A yarn to be used to make the protective jacket fabric is made by wrapping one longitudinal strand of stainless steel wire having a diameter of 0.11 mm and one parallel strand of an ultrahigh molecular weight polyethylene fiber having a tensile strength of 3 GPa modulus of 171 GPa, elongation of 2.7 percent, denier of 650 and 120 filaments per strand or end. This yarn is commercially available as Spectra® 1000 fiber from Allied Corporation. The wrapping fiber is a polyester of 500 denier, 70 filaments per end, having a tensile strength of 1.00 GPa, modulus of 13.2 GPa, elongation of 14 percent. For yarn A two layered wraps of the above polyester fiber are used to wrap the parallel strands of wire and high strength polyethylene.

[0014] For yarn B one layer of the ultrahigh molecular weight polyethylene fiber described above is used as the innermost layer wrapped around the strands, the outer layer being the polyester fiber.

[0015] Alternatively, an aramid such as Kevlar could be used to replace the ultrahigh molecular weight polyethylene, either as the strand or as the fiber for wrapping.

[0016] Comparative Yarn C - a polyester of 3600 denier, 1 GPa tensile strength, 13.2 GPa modulus and 14 percent elongation, without wrapping.

[0017] This wrapped yarn (A or B) or comparative yarn C can then be braided, knitted, woven or otherwise made into fabric used as the jacket of this invention.

[0018] This jacket can then be used to surround ropes, webbing, straps, inflatable structure, and the like. The jacket can be made from one or more ends of yarn per carrier in the braider apparatus. Either full or partial coverage of the core of braided or parallel strands can be achieved. The yarn for the fabric used for the jacket in this invention can also be wrapped in a conventional manner such as simply wrapping the strand of high strength fiber or by core spinning or by Tazalanizing or any other method to put a wrap of yarn around the strands or strands.

Example 1 - Tests on Ropes

[0019] Three different stranded ropes, jacketed with a cut protective fabric, were tested for cut resistance. Three conventional stranded ¼-inch (0.6 cm) ropes were made and a special braided yarn fabric was used to surround the rope core as a jacket. The jacket can be formed either separately and placed on the core of rope or formed around the core during one of the manufacturing steps.

[0020] Comparative Sample 1 was a Kevlar stranded rope jacketed with fabric braided from comparative yarn C. Comparative Sample 2 was an ultrahigh molecular weight high strength polyethylene (Spectra® 900) fiber stranded rope jacketed with fabric braided from comparative yarn C. Example of this invention Sample 3 was the above-described ultrahigh molecular weight polyethylene (Spectra®) fiber strand rope, surrounded with a jacket braided from Yarn A Spectra 900 fiber has a denier of 1200, 118 filaments per strand typically, tensile strength of 2.6 GPa, modulus of 120 GPa and elongation of 3.5 percent.

[0021] The three jacketed ropes were tested by a guillotine test. In the guillotine test, the rope was held in a fixture so its movement was restricted. Clamps prevented it from moving along its axis and the rope was inside two pieces of pipe to prevent it from deflecting during cutting. The two pieces of pipe were separated very slightly where the blade made the cut. The maximum force needed to completely sever the rope was measured.

[0022] In the second test, the cut-damage test, the rope was laid on a wooden surface without further restraint. A blade was then forced into the rope at 250 pounds (113.6 kg) of force. The damaged ropes were tested for retained strength. In both tests a new Stanley blade no. 1992 was used for each sample tested. The results of the test are given below.

[0023] Observation of the cut damage test ("abused") ropes showed that the Sample 1 rope was cleanly cut part way through. The Sample 2 rope jacket was also partly cut through but the filaments were not as cleanly cut. Sample 3 rope showed only a depression where the blade was pressed. There was no evidence of even the jacket having been cut. Because of this only Sample 3 rope was tested at 500 pounds force in the cut damage test. It retained 92 percent strength and sustained no jacket cutting.

Example 2 - Abrasion Resistance

[0024] Comparative Sample 2 and Sample 3 (this invention) were tested for abrasion resistance of the jacket by the test described below. Sample 3 was a ¼-inch (0.6 cm) stranded rope jacketed with a braided fabric of yarn A.

[0025] In the test each sample rope was bent in a 90 degree angle over a 10-inch (25.3 cm) diameter abrasive wheel. The ropes were loaded with 180 pounds (81.8 kg) and reciprocated through a 3-inch (7.6 cm) stroke as the abrasive wheel rotated at 3 rpm. The test ended when the jacket wore through. The number of strokes (cycles) for each was 8 for Comparative Sample 2 and 80 for Sample 3.

Example 3 - Braided Rope

[0026] Four ¼-inch (0.6 cm) braided ropes were tested with various jackets. Comparative Sample 4 rope was braided from the high strength, ultrahigh molecular weight polyethylene yarn described above and the jacket was braided from a polyester yarn of 1000 denier, 192 filaments per end, 1.05 GPa tensile strength, 15.9 GPa modulus, and 15 percent elongation.

[0027] Sample 5 rope was braided from Kevlar yarn of 1875 denier, 2.53 GPa tensile strength, 60.4 GPa modulus and 3.5 percent elongation. The jacket was as in Sample 3.

[0028] Sample 6 rope was also braided, from the high strength ultrahigh molecular weight polyethylene yarn described above, under low tension to give a "soft" rope. The jacket used was as in Sample 3.

[0029] Sample 7 rope was identical to Sample 6 except more tension was applied during braiding of the rope to create a "hard" rope.

[0030] A fixed load was applied to the rope as in Example 1. When the ropes were taut under the knife, there was little difference in cut resistance between ropes. In the cut damage test, the results are below.

Best Mode

[0031] The following is the best mode of this invention.

[0032] It is believed the most cut resistant structure, rope, webbing or strap, would use either of the above described ultrahigh molecular weight polyethylene fibers as core, either braided or as strands, covered by a jacket made, preferably braided, from a yarn having the inner strands of 0.11 mm stainless laid parallel to a strand of the ultrahigh molecular weight polyethylene fiber of highest tensile strength (Spectra 1000), the strands being wrapped with an inner wrap of the lower tensile strength polyethylene fiber (Spectra 900) and outer wrap of polyester fiber described in yarn B, above.

Claims

1. A cut resistant article comprising
a cut resistant jacket surrounding
a less cut resistant member
said jacket comprising a fabric of yarn, said yarn consisting essentially of at least one high strength longitudinal strand having a tensile strength of at least 1 GPa, and said strand being wrapped with a fiber.

2. The article of claim 1 wherein said fiber wrapped around said strand also has a tensile strength of at least 1 GPa.

3. The article of claim 1 wherein the less cut resistant member is selected from the group consisting of rope, webbing, strap, hose and inflatable structure.

4. The article of claim 1 wherein the stand is selected from the group consisting of aramid, ultrahigh molecular weight polyolefin, carbon, metal, fiber glass and combinations thereof.

5. The article of claim 1 wherein the fiber wrapping is selected from the group consisting of aramid fiber, ultrahigh molecular weight polyolefin fiber, carbon fiber, metal fiber, polyamide fiber, polyester fiber, fiber glass, polyacrylic fiber, normal molecular weight polyolefin fiber and combinations thereof.

6. The article of claim 2 wherein the fiber wrapping is selected from the group consisting of aramid fiber, ultrahigh molecular weight polyolefin fiber, carbon fiber, metal fiber and combinations thereof.

7. The article of claim 6 wherein the fiber wrapping also contains a lower strength fiber selected from the group consisting of polyamide, polyester, fiber glass, polyacrylic fiber and combinations thereof.

8. The article of claim 1 wherein more than one jacket surrounds said less cut resistant member.

9. The article of claim 1 wherein said jacket also comprises a material present in the interstices of the fabric to bond the yarn of fabric to adjacent yarn of the fabric, thereby increasing penetration resistance of the jacket.

10. The article of claim 9 wherein said material is an elastomer.

11. The article of claim 9 wherein the selected from the group consisting of polyurethane, polyethylene and polyvinyl chloride.