Note: Descriptions are shown in the official language in which they were submitted.
1284402
CUT RESISTANT JACKET FOR ROPES, WEBBING,
STRAPS. INFLATABLES AND THE LIKE
BACKGROUND OF THE INVENTION
This invention relates to a cut resistant jacket
for ropes, webbing, straps, inflatables and the like, more
particularl~ 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 fiber.
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. 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. 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.
By ultrahigh molecular weight is meant 300,000 to
7,000,000. Normal molecular weight is then below 300,000.
SUMMARY OF THE INVENTION
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.
It is preferred that the fiber wrapped around the
strand also have a tensile strength of at least 1 GPa.
The less cut resistant member can be selected
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from the group consisting of rope, webbing, strap, hose
and inflatable structures.
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.
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 ~e 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. ~1hen the
iber wrapping is a high strength fiber having strength
over l 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.
The polyolefin fiber of this invention can be
ultrahigh molecular weight polyethylene or polypropylene,
preferably polyethylene, commercial examples are Spectra~
900 or Spectra~ lO00.
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.
The article of this invention can also have more
than one jacket surrounding the less cut resistant member.
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
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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.
D~SCRIPTION OF THE PREFERRED EMBODIMENTS
Yarns for Jacket Fabric
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 thé above polyester ~iber
are used to wrap the parallel strands of wire and high
strength polyethylene.
For yarn B one layer of the ultrahigh molecular
weight polyethylene fiber described above i9 used as the
innermost layer wrapped around the strands, the outer
layer being the polyester fiber.
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.
Comparative Yarn C - a polyester of 3600 denier,
1 GPa tensile strength, 13.2 GPa modulus and 14 percent
elongation, without wrapping.
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.
This jacket can then be used to surround ropes,
webbing, straps, inflatable structure, and the like. The
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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 strand or strands.
Example 1 - Tests on Ropes
Three different stranded ropes, jacketed with a
cut protective fabric, were tested for cut resistance.
Three conventional stranded 1/4-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.
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 ~as 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.
- 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 rnade the cut. The maximum
force needed to completely sever the rope was measured.
In the second test, the cut-darnage test, the
rope was laid on a wooden surface without further
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restraint. A blade was then ~orced.into the rope ~t 25~
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 tests are yiven below.
Guillotine Test Results
Pounds of Force to Cut
Comparative Comparative
TestSample 1 Sample 2 Sample 3
(kg) (kg) (kg)
1 132 (60 ) 227 (103) 684 (311)
2 139 (61.8) 335 (152) 638 (290)
3 144 (65.5) 286 (130) 616 (280)
Avg. 138 (62.7) 282 (12~) 646 (294)
Cut Damage Test Results, Percent Strength Retained
73 85 97
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
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 ~4-inch
(0.6 cm) stranded rope jacketed with a braided fabric of
yarn A.
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 Sarnple 3.
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Example 3 - Braided Rope
Four ~4-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.
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.
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.
Sample 7 rope was identical to Sample 6 except
more tension was applied during braiding of the rope to
create a "hard" rope.
A fixed load was applied to the rope as in
Example 1. When the ropes were taut under the kni~e,
there was little difference in cut resistance between
ropes. In the cut damage test, the results are below.
Cut Damage Tolerance
Percent Strength Retained
Sample
~ 5 6 7
43 54 lO0 82
Best Mode
The following is the best mode of this invention.
It is believed the most cut resistant structure,
rope, webbing or strap, would use either o~ 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
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polyethylene fiber (Spectra 900) and outer wrap of
polyester fiber described in yarn B, above.
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