Method and Apparatus for a Composite Cable Safety Net

Abstract

A net is formed by joining cables which are over-knitted with cord. A cable may be made of wire or stainless-steel cable. A composite cable is a cable that is over-knitted with cord to form a composite cable. The cord may be made of fibrous material and in some embodiments is made of aramid fibers. Adjacent composite cables are joined at regular intervals to form a net. In some embodiments, composite cables are composed of cable with an over-knitted cord, inter-knitted at junctions that are spaced at regular intervals to form a net. The individual cables are over-knitted with cord and the junctions are formed as the over-knitted cords are inter-knitted.

Description

TECHNICAL FIELD

The present disclosure relates to cables, wires, methods of manufacture and uses thereof.

BACKGROUND OF THE INVENTION

Safety netting and fences arranged around high-rise buildings protect construction workers and prevent debris from falling to the ground. Nets and fences are constructed of linked wire, cable or metal fibers. Nets of combined at intervals cord generally have at least one stainless steel line surrounded by aramid fibers. Aramid fibers, also known as aromatic polyamide fibers, are a class of heat-resistant, strong synthetic fibers used in high-strength applications such as ballistic-rated body armor and marine cordage.

Suicide-prevention barriers may be constructed of stainless steel-netting or fencing, in a pattern that prevents climbing and also to catch objects falling from construction heights. A challenge in the design of suicide barriers is to provide a structurally sound and vandal-proof deterrent while maintaining the visual appeal of the building or structure onto which the barrier is mounted

Technical textile-production is a rapidly developing industry, with textile structures replacing expensive, heavy or technically inferior constructions.

Nets in the current state of the art are now engineered with metallic cores and composite materials, using new warp-knitting and stitch-bonding techniques.

“Cord” refers to any textile strand, twine, rope, line or thread. In the context of this embodiment, the cord is used in a novel knitting method to produce a warp-knitted tubular fabric.

SUMMARY

A net of composite cable joined at intervals is made of various materials, each of which is difficult to cut. At its core is a cable made of metal wire, cable or other dense material around which is knitted a strong cord. The knitted cord is of a material that requires a sharp blade to sever, while the dense cable requires a bolt cutter or similar tool that crushes the dense material to sever it. Together the cable and over-knitted cord make a strong composite cable that is difficult to cut.

The over-knitted, composite cables are attached to each other at intervals to form a net in one of various ways, described below.

The cord is composed of fibrous material, and in some embodiments is aramid fibers, used to form a warp-knitted tubular fabric that surrounds a cable. Loops are formed continuously on a needle, with the loops surround a cable and are further interlaced at intervals to form a net.

In one embodiment, adjacent, cables are joined at intervals to form a net with hexagonal or similarly shaped openings.

Cable may have a wire core made of stainless steel. One skilled in the art understands that a stainless-steel core may be composed of a solid wire or of a twisted or braided cable. Around this core, fibers may be spun, knitted, braided or wrapped. Cable is over-knitted with cord to form a composite cable. In some iterations, a sheath surrounds the composite cable.

In an embodiment, cord is knitted over the cables to strengthen the cables. This cord may be made of aramid fibers. In another iteration, a cable core is a bundle of twisted wires surrounded by, or “over-knitted” by knit cords. In some embodiments the cable core is of twisted or braided stainless steel, and the knit cords are made of aramid fibers. The combination of cable core and surrounding knitted cord provides a composite cable that can be attached at intervals to form a strong net that is difficult to cut. In some embodiments at least one outer layer of sheathing covers each over-knitted, composite cable.

An attempt to cut such a cable with a lever-driven cutting tool (for example, with wire- or bolt-cutters) pushes the cable's fibers away from the cutting tool, preventing cutter blades from acquiring sufficient purchase to cut both the metal core and the over-knitted cord. Wire cutters and bolt cutters are designed to compress metal. Using them on metal forces the metal to separate. Fibrous materials cut best with a sharp blade that severs the fibers. To cut the composite cable of the disclosure, one would need to cut the over-knitted cord with a first tool, and then attempt to use a second tool to sever the metal cable core. Time and effort to do so would deter an individual from attempting to cut through a net made of this combination of materials.

In another iteration, a cable core is composed of a metal cable of twisted wires. The metal cable, over-knitted with cord, and further sheathed in an additional cover (sheath), forming a composite cable. In some embodiments, the metal cable is composed of twisted or braided stainless steel, and the over-knitted cords are aramid fibers. The combination of cables and knitted fibers and sheath provides a composite cable that can be attached at intervals to form a net of a strength that is difficult to cut. As with the above iteration, an attempt to cut such a composite cable with a cutting tool would push rather than cut the fibrous sheth and over-knitted cord. As in the first iteration, one would need to cut the sheathing, knitted fibers, and metal-cable core with two or more tools. Time and effort to do so would deter an individual from attempting to cut through a net made of this combination of materials.

In one application, a net is made out of a set of adjacent cables that are over-knitted with cord and cords are inter-knitted, also referred to as interlaced, forming junctions thus providing a net.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of an example embodiment.

FIG. 2 is a perspective view of a junction in a net of the embodiment.

FIG. 3 is a detail view of a section of net and junction in the configuration of FIG. 2.

FIG. 4 is a schematic of the configuration of FIG. 3.

FIG. 5 is a cross-section of cables composed of more than one cable plus over-knitted fibers.

FIG. 6. is a cross-section of cables of twisted wires, over-knitted with fibers.

FIG. 7a is a diagram of a process for manufacturing a knit.

FIG. 7b is an example knit produced by the process in the diagram of FIG. 7a.

FIG. 8a is a diagram of a process for manufacturing the apparatus of FIG. 1.

FIG. 8b is an example knit as used to over-knit cables in the apparatus of FIG. 1

FIG. 9 is a perspective view of a junction in a net of an iteration of the embodiment.

FIG. 10 is a cross-section of cables of more than one cable plus over-knitted fibers, plus sheathing.

FIG. 11 is a cross-section of cables of twisted wires that are over-knitted and sheathed.

DETAILED DESCRIPTION

FIG. 1 shows an example net 100. A set of cables is combined at intervals to form a net. Single cables are over-knitted and joined with textile cord at regularly spaced intervals, forming junctions. In some embodiments the textile cord is made up of aramid fibers. In this disclosure the cable may be stainless-steel wire, filament, twisted cable, braided cable or other dense material or combination of materials. Cables may be composed of two or more twisted or otherwise-combined wires. One skilled in the art is familiar with the various types of cables.

FIG. 2, FIG. 3 and FIG. 4 each show a junction in a section of netting 100. A junction 130 of cables 110,112 is over-knitted with cords 140 and 142. A single cable segment 120 is also over-knitted with cord 142. Cord 142 is knitted to form a seamless tubular warp-knitted fabric that surrounds cable 110. Cord 140 is knitted to form a seamless tubular warp-knitted fabric that surrounds cable 112. One skilled in the art understands that cables 110 and 112 may be made of wire, filament, cable or the like. Referring to FIG. 3 and FIG. 4, a net with six-sided voids is created when a set of parallel cables are joined at regular intervals. The diagram in FIG. 4 shows four adjacent cables, one skilled in the art understands that any number of adjacent cables may be joined in the manner described and depicted in the illustration. A junction 130 is formed as cables 110 and 112 are inter-knitted with cords 142 and 140. “Inter-knitted” or “interlaced” refers to the knitting together of the cord from one cable with the cord of another cable to form a junction. One skilled in the art understands that junctions 130 are offset from junctions 132 (FIG. 3) and so form a net with six-sided voids.

FIG. 5 is a cross-sectional diagram 118 of an example junction 130 (FIG. 2) in an example net. It shows two cables. A first cable made up of twisted wires, 110a, 110b, and 110c, is over-knitted with cords 142a, 142b, 142c. A second cable is made up of twisted wires, 112a, 112b and 112c, is over-knitted with cords 140a, 140b and 140c.

FIG. 6 is a cross-sectional diagram/detail view 121 of a single cable, the full view of which is shown in FIG. 2 (121). In an example embodiment, a first cable is itself composed of wires 110a, 110b and 110c twisted together to form a cable, over-knitted with cords 142a, 142b and 142c.

One skilled in the art understands that cords knitted over cables in a seamless tubular warp-knitted fabric on single cables may be further knitted over junctions, as demonstrated in junction 130 of FIG. 2.

FIG. 7a and FIG. 7b illustrate a process for creating a seamless, warp-knitted, tubular fabric 10. This fabric makes up the over-knitted cord that surrounds the cables described above. In the process, a guide bar 40 is fully threaded and overlaps needle bar 36. Another guide bar 46 is fully threaded and overlaps needle bar 38. Still other guide bars 42 and 44 are threaded through only one yarn guide each at the extremities of the fabric, and overlap both needle bars 36/38. A seamless, tubular, warp-knitted fabric is formed. One skilled in the art understands that with the right threading arrangement, many tubes can be formed across a machine, and the diameter of tubes can be altered by changing the threading arrangement.

FIGS. 8a and 8b illustrate a process for creating a seamless, tubular warp-knitted fabric 100 knitted over and between cables to form the composite cable which forms the net described in FIG. 1, FIG. 2, FIG. 3 and FIG. 4. A guide bar 140 is fully threaded and overlaps the needle bar 136. Another guide bar 146 is fully threaded and overlaps needle bar 138. Still other guide bars 142 and 144 are threaded only through one yarn guide each at the extremities of fabric, and overlap both needle bars 136/138. Cables 110, 110′, 112, and 112′ are over-knitted with cords 140, 142, 144 and 146. A seamless tubular warp-knitted fabric is formed by over-knitted cords 140, 142, 144 and 146, over cables 110, 112, 110′ and 112′ and inter-knitted cords, at regular intervals, as visible in inter-knitted portion 130 and inter-knitted portion 132.

FIG. 9 shows a junction in a section of netting in an iteration of the embodiment 200. Portions of the outer sheath 224 and inner sheath 222 are cut away to show cables and cords underneath. Sheaths 222 and 224 may be made of various textile materials including woven aramid fibers. A junction 230 of cables 210, 212 is over-knitted with cords 240 and 242 and sheathed by inner sheath 222 and outer sheath 224. A single cable segment 220 is also over-knitted with cord 242. Cord 242 is knitted to form a seamless tubular warp-knitted fabric that surrounds cable 210. Cord 240 is knitted to form a seamless tubular warp-knitted fabric that surrounds cable 212. One skilled in the art understands that cables 210 and 212 may be made of wire, filament, cable or the like A junction 230 is formed as cables 210 and 212 are inter-knitted with cords 242 and 240. “Inter-knitted” or “interlaced” refers to the knitting together of the cord from one cable with the cord of another cable to form a junction.

FIG. 10 is a cross-sectional diagram and detail view 219 (FIG. 9) of an example junction in the net. A Composite cable made of twisted wires 210a, 210b and 210c is over-knitted with cord 242a, 242b and 242c. A first sheath 222 surrounds the first composite cable 210a, 210b and 210c as well as its over-knitted cord 242a, 242b and 2420c. A second sheath 224 surrounds the first sheath 222. A third sheath 226 surrounds the second composite cable 212a, 212b and 212c and its over-knitted cord 240a, 240b and 240c. A fourth sheath 228 surrounds the third sheath 226 over part of a composite cable. Sheaths 222, 224, 226 and 228 are fastened together at this joint.

FIG. 11 is a cross-sectional diagram/detail view 221 of a single cable (FIG. 9). In an example embodiment, the cable is itself composed of wires or cables 210a, 210b and 210c, joined in parallel to form a composite cable, which is over-knitted with cord 242a, 242b and 242c. One skilled in the art understands that the knitted cord appears in multiple locations in cross section. A first sheath 222 surrounds the first cable 210a, 210b and 210c and over-knitted cord 242a, 242b and 242c. A second sheath 224 surrounds the first sheath 222.

Although “fibers” are referred to as “aramid fibers,” one skilled in the art understands that various fibers, natural and synthetic, may be used for various purposes. Cable cords may be stainless-steel cords, however one skilled in the art understands that various materials, including metal cables, rope or line, or composites of these may be used.

Claims

1. A composite cable comprising:

at least a first wire; and

said first wire over-knitted with at least a first cord; wherein

said composite cable provides a strength of both the cord and wire and requires cutting both the cord and wire to sever the composite cable.

2. The composite cable of claim 1 further comprising:

at least a second wire over-knitted with at least a second cord; and

said second cord inter-knitted with said first cord at regular intervals; wherein a net is formed.

3. A composite cable comprising:

at least a first wire combined with at least a second wire to form a cable; and

said cable over-knitted with at least one cord; wherein

said composite cable provides a strength of the first wire, the second wire and the cord and requires cutting both the cord and the first wire and the second wire to sever the composite cable.

4. The composite cable of claim 3 wherein:

said at least one cord is knitted over said cable in a seamless tubular warp-knitted fabric.

5. The composite cable of claim 3 wherein:

said first wire and said second wire are comprised of metal; and

said at least one cord is comprised of a fibrous material.

6. The composite cable of claim 3 wherein:

said first wire and said second wire are comprised of stainless steel; and

said at least one cord is comprised of aramid fibers.

7. A net comprising:

a plurality of adjacent composite cables, each having a core; and

a knitted cord surrounding each said core; and

said knitted cord inter-knitted at a first set of regular intervals with a knitted cord of at least one adjacent composite cable, forming a net.

8. The net of clam 7 wherein:

alternate adjacent cables inter-knitted at a second set of regular intervals that are offset from said first set of regular intervals; wherein

a net is formed having voids with hexagonal perimeters bounded by said plurality of adjacent composite cables.

9. The net of claim 7 wherein:

said core is comprised of twisted metal cable: and

said knitted cord is comprised of fibrous material.

10. The net of claim 7 wherein:

said core is comprised of twisted stainless steel cable; and

said knitted cord is comprised of aramid fibers.

11. The net of claim 7 further comprising:

said core is comprised of braided stainless steel cable; and

said knitted cord is comprised of spun aramid fibers.

12. The net of claim 7 further comprising

a first sheath, surrounding said core sheathed in knitted cord; wherein

said sheath expands to cover both composite cables where they join at regular intervals.

13. The net of claim 12 further comprising

a second sheath surrounding said first sheath; wherein

said first sheaths are knitted together with said second sheaths at said first set of regular intervals.

14. A method of manufacturing the net of claim 7, the method comprising:

knitting a first cord over a first cable; and

knitting a second cord over a second cable; and

inter-knitting said first cord with said second cord at regular intervals along said first cord and said second cord; and

repeating the aforementioned steps with a plurality of cords and cores; wherein a net is manufactured.

15. The method of claim 14 further comprising:

knitting said first cord over said first cable; and

forming a seamless tubular warp-knitted fabric that surrounds said first cable; and

knitting said second cord over said second cable; and

forming a seamless tubular warp-knitted fabric that surrounds said second cable.