CA2058715A1 - Flexible cord with high modulus organic fiber strength member - Google Patents
Flexible cord with high modulus organic fiber strength memberInfo
- Publication number
- CA2058715A1 CA2058715A1 CA 2058715 CA2058715A CA2058715A1 CA 2058715 A1 CA2058715 A1 CA 2058715A1 CA 2058715 CA2058715 CA 2058715 CA 2058715 A CA2058715 A CA 2058715A CA 2058715 A1 CA2058715 A1 CA 2058715A1
- Authority
- CA
- Canada
- Prior art keywords
- electrical cable
- jacket
- filler layer
- strength member
- single yarn
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000000835 fiber Substances 0.000 title abstract description 5
- 239000000945 filler Substances 0.000 claims abstract description 42
- 239000006260 foam Substances 0.000 claims abstract description 41
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 31
- 229910052802 copper Inorganic materials 0.000 claims abstract description 29
- 239000010949 copper Substances 0.000 claims abstract description 29
- 239000004952 Polyamide Substances 0.000 claims abstract description 15
- 229920002647 polyamide Polymers 0.000 claims abstract description 15
- 229920000915 polyvinyl chloride Polymers 0.000 claims description 45
- 239000004800 polyvinyl chloride Substances 0.000 claims description 45
- 239000004020 conductor Substances 0.000 claims description 34
- 239000004088 foaming agent Substances 0.000 claims description 4
- 238000000034 method Methods 0.000 claims description 4
- 239000004156 Azodicarbonamide Substances 0.000 claims description 3
- XOZUGNYVDXMRKW-AATRIKPKSA-N azodicarbonamide Chemical compound NC(=O)\N=N\C(N)=O XOZUGNYVDXMRKW-AATRIKPKSA-N 0.000 claims description 3
- 235000019399 azodicarbonamide Nutrition 0.000 claims description 3
- 238000001125 extrusion Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 229920000642 polymer Polymers 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 claims 2
- 238000004804 winding Methods 0.000 claims 2
- 239000012212 insulator Substances 0.000 abstract description 2
- 240000000491 Corchorus aestuans Species 0.000 description 10
- 235000011777 Corchorus aestuans Nutrition 0.000 description 10
- 235000010862 Corchorus capsularis Nutrition 0.000 description 10
- 239000004814 polyurethane Substances 0.000 description 8
- 229920002635 polyurethane Polymers 0.000 description 8
- 238000009413 insulation Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 239000002131 composite material Substances 0.000 description 3
- 229920000742 Cotton Polymers 0.000 description 2
- 229920003368 Kevlar® 29 Polymers 0.000 description 2
- 229920003369 Kevlar® 49 Polymers 0.000 description 2
- 229920000297 Rayon Polymers 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000008520 organization Effects 0.000 description 2
- 239000002964 rayon Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000011800 void material Substances 0.000 description 2
- 101100421296 Caenorhabditis elegans set-6 gene Proteins 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 229920003188 Nylon 3 Polymers 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229920006334 epoxy coating Polymers 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000002966 varnish Substances 0.000 description 1
Landscapes
- Insulated Conductors (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An electrical cable has a single yarn polyamide fiber strength member with a plurality of copper strands positioned adjacent thereto. An insulator jacket is extruded over the copper strands and the strength member to provide an insulated lead of high strength. A foam filler layer is extruded over a plurality of such leads, and a non-porous jacket is extruded over the foam filler layer, providing a light weight, flexible, high-strength, multi-lead cable, which is easily stripped by automated equipment.
An electrical cable has a single yarn polyamide fiber strength member with a plurality of copper strands positioned adjacent thereto. An insulator jacket is extruded over the copper strands and the strength member to provide an insulated lead of high strength. A foam filler layer is extruded over a plurality of such leads, and a non-porous jacket is extruded over the foam filler layer, providing a light weight, flexible, high-strength, multi-lead cable, which is easily stripped by automated equipment.
Description
-1- 2~ 3 FLEXIBLE CORD WITH HIGH MODULUS
ORGANIC FIBER STRENGTH MEMBER
The invention relates in general to a reinforced electrically conductive cable and ~n particular to an electrical cable having a single yarn high modulus or~anic fiber strength ~ember surrounded by metal conductors.
Conventional electrical cables of the type used in household electric cord set6 are manufactured from stranded copper wire surrounded by a filler material, such as paper, ~ute, cotton or rayon. The filler material reduces the amount of jacket material required for the cord and is typically helically wrapped about the ctranded copper conductors. An insulator, such as a polyYinylchloride jacket, is extruded over the filler material to complete the cord.
Unfortunately those household cord sets suffer from several drawbacks. At present, there is a requirement that household electric cord sets have sufficient tensile strength to withstand a tensile force of 170 pounds. The pri~ary strength providing members in prior art cord sets are the conductors and the filler ~aterial within the cord set, which may fail under the ~tress of such a force.
In addition, it has become relatively expensive to manufacture cord sets using paper and jute fillers. The paper and jute fillers are meant to occupy volume, as well as provide tensile strength within the cable, ~o that for a given outside diameter of a cable jacket less polyvinylchloride insulation is required, thereby saving money. It is often necessary for an electric plug or connector to be attached to the cord. As a result, the outer layer of polyvinylchloride insulation must be removed completely without nicking or damaging the copper wire conductor C~f3}~ ~/?~
ORGANIC FIBER STRENGTH MEMBER
The invention relates in general to a reinforced electrically conductive cable and ~n particular to an electrical cable having a single yarn high modulus or~anic fiber strength ~ember surrounded by metal conductors.
Conventional electrical cables of the type used in household electric cord set6 are manufactured from stranded copper wire surrounded by a filler material, such as paper, ~ute, cotton or rayon. The filler material reduces the amount of jacket material required for the cord and is typically helically wrapped about the ctranded copper conductors. An insulator, such as a polyYinylchloride jacket, is extruded over the filler material to complete the cord.
Unfortunately those household cord sets suffer from several drawbacks. At present, there is a requirement that household electric cord sets have sufficient tensile strength to withstand a tensile force of 170 pounds. The pri~ary strength providing members in prior art cord sets are the conductors and the filler ~aterial within the cord set, which may fail under the ~tress of such a force.
In addition, it has become relatively expensive to manufacture cord sets using paper and jute fillers. The paper and jute fillers are meant to occupy volume, as well as provide tensile strength within the cable, ~o that for a given outside diameter of a cable jacket less polyvinylchloride insulation is required, thereby saving money. It is often necessary for an electric plug or connector to be attached to the cord. As a result, the outer layer of polyvinylchloride insulation must be removed completely without nicking or damaging the copper wire conductor C~f3}~ ~/?~
strands and causing a loss of conductiYity which may result in an increase in the resistivity of the wire.
Such an unwanted increase in resistivity may cause the wire to overheat when it i~ connected to a low impedance electrical load. As a result, it is necessary to remo~e the insulating polyvinylchloride layer manually, after which the jute or paper filling is removed manually. Attempts to automate the labor-intensive insulation stripping process have met with little success because complete removal of the insulation and filler often results ln damage to the underlying conductors.
Cords with multiple insulated leads conventionally have an outer jacket of polyvinylchloride, which holds the leads together and provides additional protection against damage. To achieve a ~iven overall cord thickness and fill the grooves between leads, paper or jute fillers are bundled with the inner leads and a polyvinylchloride jacket is extruded around the bundle, thereby reducing the amount of polyvinylchloride used. These fillers result in the same obstacles to automated stripping as mentioned above.
In addition, such ~illers do not have the flexibility that polyvinylchloride has, and so add to the stiffness of the cord. To retain maximum flexibility, the grooves between leads would have to be filled with polyvinylchloride, which would make the cable unnecessarily heavy.
Co-axial cords are known which contain organic foam. However, because the purpose of the foam is to improve electrical transmission through the dielectric properties of the foam, the foam is extruded in contact with the conductive metal of the cord. The foam i~ not used as a filler material between two non-porous, ~nsulating jackets, as paper or jute are used as mentioned above.
Such an unwanted increase in resistivity may cause the wire to overheat when it i~ connected to a low impedance electrical load. As a result, it is necessary to remo~e the insulating polyvinylchloride layer manually, after which the jute or paper filling is removed manually. Attempts to automate the labor-intensive insulation stripping process have met with little success because complete removal of the insulation and filler often results ln damage to the underlying conductors.
Cords with multiple insulated leads conventionally have an outer jacket of polyvinylchloride, which holds the leads together and provides additional protection against damage. To achieve a ~iven overall cord thickness and fill the grooves between leads, paper or jute fillers are bundled with the inner leads and a polyvinylchloride jacket is extruded around the bundle, thereby reducing the amount of polyvinylchloride used. These fillers result in the same obstacles to automated stripping as mentioned above.
In addition, such ~illers do not have the flexibility that polyvinylchloride has, and so add to the stiffness of the cord. To retain maximum flexibility, the grooves between leads would have to be filled with polyvinylchloride, which would make the cable unnecessarily heavy.
Co-axial cords are known which contain organic foam. However, because the purpose of the foam is to improve electrical transmission through the dielectric properties of the foam, the foam is extruded in contact with the conductive metal of the cord. The foam i~ not used as a filler material between two non-porous, ~nsulating jackets, as paper or jute are used as mentioned above.
-3- 2 ~ ) J . l3 What 16 needed, then, i8 an improved electrical cable or cord strong enough to withstand a tensile force of 170 pounds or more, requiring a minimum of polyvinylchloride, retaining maximal flexibility and minimal weight, and which may be ~tripped of insulation quickly and easily in order to expose the copper conductors for connection to plug assemblies, connectors and the like.
An electrical cable embodying the present invention has a single yarn tensile ~trength member.
plurality of fine copper strands ~re helically wound about the single yarn tensile strength member and in contact with it. A polyvinylchloride insulated jacket is extruded over the copper 6trands. A
polyvinylchloride foam filler layer may be extruded over a plurality of such insulated cables, and a non-porous polyvinylchloride jacket extruded over the foam filler layer.
It is a principal aspect of the present invention to provide a high strength electric cord or cable for household use.
It is another aspect of the present invention to provide an electrical cable from which the insulation easily may be stripped by automated equipment without damaging the conductors thereof.
It is yet another aspect of the present invention to provide an electrical cable with multiple leads inside an outer iacket of maximal flexibility and minimal weight which easily may be stripped by automated equipment.
Other aspects of the present invention will become obvious to one skilled in the art upon a perusal of the specific~tion and the claims in light in the accompanying drawings.
An electrical cable embodying the present invention has a single yarn tensile ~trength member.
plurality of fine copper strands ~re helically wound about the single yarn tensile strength member and in contact with it. A polyvinylchloride insulated jacket is extruded over the copper 6trands. A
polyvinylchloride foam filler layer may be extruded over a plurality of such insulated cables, and a non-porous polyvinylchloride jacket extruded over the foam filler layer.
It is a principal aspect of the present invention to provide a high strength electric cord or cable for household use.
It is another aspect of the present invention to provide an electrical cable from which the insulation easily may be stripped by automated equipment without damaging the conductors thereof.
It is yet another aspect of the present invention to provide an electrical cable with multiple leads inside an outer iacket of maximal flexibility and minimal weight which easily may be stripped by automated equipment.
Other aspects of the present invention will become obvious to one skilled in the art upon a perusal of the specific~tion and the claims in light in the accompanying drawings.
-4~ 7 ~ '~
FIG. 1 i~ an isometric view of an electrical cable embodying the present invention;
FIG. 2 i~ a ~ection taken 6ubstantially along line 2--2 of FIG. 1 showing detail~ of the internal arrangement of the electrical cable;
FIG. 3 is an isometric view of an alternate embodiment of the electrical cable;
FIG. 4 i~ a 6ection taken substantially along line 4--4 of FIG. 3 showing detail~ of the internal arrangement of the electrical cable:
FIG. 5 is an i60metric view of another alternate embodiment of the electrical cable;
FIG. 6 is a section taken substantially along line 6--6 of FIG. 5 showing details of the internal organization of the electrical cable;
FIG. 7 is an isometric view of the cable of FIG. 6 positioned proximately with a pair of cutters, portions of which are shown;
FIG. 8 is an elevational view, partially in section, of the cable of FIG. 7 with the cutters engaging it;
FIG. 9 is an end view of the cable and cutters of FIG. 8;
FIG. 10 is an elevational view, partially in section, of the cable of FIG. 8 showing an outer ~acket being stripped off by the cutters:
FIG. 11 is an isometric view of the cable of FIGS. 1 and 2 positioned proximately with a pair of cutters, portions of which are 6hown;
FIG. 12 is an elevational view, partially in section, of the cable of FIG. 11 with the cutters engaging it;
FIG. 13 is an end view of the cable and cutters of FIG. 12;
FIG. 14 is an elevational view, partially in 2 f~
section, of the cable of FIG. 12 ~howing a jacket being stripped off by the cutters.
FIG. 15 is an lsometric view of yet another alternate embodiment of the ~lectrical cable;
FIG. 16 is a section taken suhstantially along line 6--6 of FIG. 15 showing detail of the internal organization of the electrical cable FIG. 17 is an isometric view of the cable of FIG. 16 positioned proximately with a pair of cutters, portions of which are shown;
FIG. 18 is an elevational view, partially in section, of the cable of FIG. 17 with the cutters engaging it;
FIG. 19 is an end view of the cable and cutters of FIG. 1~;
and, FIG. 20 is an elevational view, partially in section, of the cable of FIG. 18 ~howing an outer jacket being stripped off by the cutters;
Referring now to the drawings and especially to FIGS. 1 and 2, an electrical cable or flexible cord embodying the present invention and generally identified by numeral 10 is shown therein. The electrical cable 10 includes a single yarn, centrally located, circular cross section tensile strength member 12. The strength member 12 is comprised of a multi-filament 1500 denier polyamide yarn, coated with polyurethane, having a high modulus and of the type ~old under the designation Kevlar 29 or alternatively, Kevlar 49. The yarn has a diameter of 0.010-0.015 inches. A coating of polyurethane covers the polyamide yarn in order to prevent it from fraying.
Alternatively, nylon, varnish or epoxy coating could be -6~
used to prevent fraying of the polyamide yarn. It should be appreciated that the polyurethane fray resisting coating also meets Underwriters Laboratories 90C. temperature standards. A plurality of c~pper ~trands 14 is wound helically about the slngle yarn ~trength member 12. The plurality o~ copper strands 14 comprises between 41 ~nd 65 strands in the present embodiment. Each of the Rtrands 14 has a circular cross section. It may be appreciated that the strands 14 are wound about the single yarn stren7th member 12 without any intermediate filler or layered material such as paper, jute, and the like being interposed in between. The plurality of strands 14 contacts and substantially completely covers the single yarn strength member 12. Each of the strands 14 has a diameter in the range of Q.0050 inches or greater. In some embodiments of the present invention each of the copper strands may have a diameter of .010 inches. For such a strand diameter, only cixteen copper strands 2V would typically comprise the plurality. A
polyvinylchloride insulating jacket 16, having a circular cross section, i5 extruded over the plurality of copper strands 14 to 6ubstantially completely cover and enclose them.
Referring now to FIGS. 3 and 4, an alternative electrical cable 30 is shown therein. The electrical cable 30 includes a single yarn high modulus polyamide tensile strength member 32 having a 6ubstantially circular cross section. The polyamide 3~ strength member 32 is composed of Kevlar 29 or Kevlar 49 and has a diameter of 0.010-0.015 inches. A
plurality of copper conductor strands 34 is helically wound about each other and located adjacent to the 6trength member 32. The copper conductor strands 34 are each 0.0050 inches or greater in diameter. In the present embodiment, be~ween 41 and 65 strands are employed. A polyvinylchloride jacket 36 is extruded ~ !;
over the strength me~ber 32 and the conductor strands 34.
In a ~till further embodiment, as may be~t be seen in FIGS. 5 and 6, a multiple-lead cable 50 has a plurality of high 6trength cords 52, 54, and 56. Each of the cords 52, 54, and 56 is substantially identical to the cable lo s~own in FIGS. 1 and 2 and described above. The cord 52 has an inner polyvinylchloride ~acket 60 which is extruded over a single yarn polyamide tensile strength member 62 coated with polyurethans and a plurality of copper conductor strands 64 are disposed ~elically about and in contact with the strength member 62. The cord 5~ has an inner polyvinylchloride jacket 70 ~urrounding and contacting a plurality of helically wound copper conductor strands 72. A ~ingle yarn polyamide tensile strength me~ber 74 is coated with polyurethane and completely surrounded by and in contact with the copper conductor strands 72. The cord 56 has an inner polyvinylchloride jacket 80 having a plurality of copper conductor ~trands 82 helically wound inside thereof with a ~ingle yarn polyamide tensile strength member 84 coated with polyurethane and completely ~urrounded by and in contact with the plurality of copper conductors 82. An outer polyvinylchloride jacket 86 surrounds and contacts the inner jacket6 60, 70 and 80. The outer polyvinylchloride jacket 86 is extruded over the jackets 60, 70 and 80.
In a still further embodiment, as may best be seen in FIGS. 15 and 16 a foam-skin composite jacket multiple-lead cable 150 has a plurality of high strength cords 1S2, 154, and 156. Each of the cords 152, 154, and 156 ~s substantially identical to the cable 10 shown in FIGS. 1 and 2 and described above.
The cord 152 has an inner polyvinylchloride jacket 160 which is extruded over a single yarn polyamide tensile strength member 162 coated with polyurethane and a ~,~r~
plurality of co~er conductor strands 164 are disposed helically about and in contact with the strenqth member 162. The cord 154 has an inner polyvinylchloride ~acket 170 ~urrounding and contacting a plurality of helically wound copper conductor strands 172. A ~ingle y3rn polyamide tensile ~trength member 174 is co~ted with polyurethane and completely surrounded by and in contact with the copper conductor strands 172. The cord 156 has an inner polyvinylchloride ~acket 180 having a plurality of copper conductor strands 182 helically wound inside thereof with a ~ingle yarn polyamide tensile strength member 184 coated with polyurethane and completely 6urrounded by and in contact with the plurality of copper conductors 182. A polyvinylchloride foam filler layer 190 surrounds and contacts the inner jackets 160, 170, and 180. The polyvinylchloride foam filler layer is formed during the extrusion process by blending loO
parts polyvinylchloride with 1 part azo-dicarbonamide 2() type foaming agent at a temperature of about 200C, which is sufficient to activate the foaming agent and melt the polyvinylchloride but insufficient to destroy the polymer. The foam filler layer has approximately 35~ void content. An outer polyvinylchloride jacket 200 surrounds and contacts the polyvinylchloride foam filler layer 190. The outer polyvinylchloride jacket 200 is extruded over the foam filler layer 190. The polyvinylchloride foam filler layer 190 can have a thickness in the range of approximately 25-75% that oP
the thickness of the outer jacket 200.
It may be appreciated that the single yarn strength member provides a number of advantages to the users of the instant invention. The single yarn high modulus tensile strength member is flexible and provides high strength to the cord 10 allowing the cord to exceed the 170 pound tensile ~trength requirement set forth by Underwriters Laboratories and other 2 f ;
_g_ 6tandards-making organizations.
It may also be appreciated that the flexible cord with multiple leads surrounded by an outer jacket of foam and a non-porou6 ~kin provides a cord that is cheaper and lighter than a cord using Rolid polyvinylchloride and more flexible than a cord using paper or jute fillers. The foam filler layer uses less polyvinylchloride than the solid polyvinylchloride needed to fill the grooves betwee~ leads in the cord, so is therefore cheaper to produce and lighter in weight than an all-~olid polyvinylchloride csrd. ~he foam filler layer is also more flexible than the same thickness of solid polyvinylchloride or paper and jute fillers. The outer jacket of polyvinylchloride meets the non-porosity requirement for cable jackets as set forth by Underwriters Laboratories and other standards-making organizations.
Additionally, ~s may best be seen in FIGS. 11 through 14, the cable 10 may be quickly and easily stripped. A cutter 90 having a pair of mating cutter halves 92 and 94 may be used to strip the polyvinylchloride jacket 16 down to the copper ~trands 14. Since there is no intermediate layer, such as paper, jute, cotton or rayon, between the copper conductor strands 14 and the polyvinylchloride jacket 16, the jacket 16 need not be cut all the way through; a thin web portion 100 may be left. The remaining thin web portion 100 then i6 ~evered by stretching it, while the copper conductor strands 14 and the inner ~trength member 12 remain intact. A
severed portion 102 of the jacket 16 i~ then removed by 61 iding it off the copper conductor strands 14. In addition, the tensile ~trength member 12, since it is located within the helically wound strands 14, is unaffected by the ~tripping process; 60 that even when 6tripped of the outer jacket 16 down to the conductor strands 14, the cable 10 retains its high strength.
2~ '~ i 3 The cable 30, 8hown in FIGS. 3 and 4, also may be stripped down to the strength mem~er 32 and the copper strands 34 and the polyvinylchloride insulation 36 easily removed therefrom. Should it be desired, the tensile strength member 32 may then be separated from the conductor strands 34 to allow the conductor strand 34 to be fitted into relatively small connectors of the type used in electrical plugs to which they must be electrically connected.
The multiple-lead cable 50 also may be stripped in a similar fashion, as may best be 6een in FIGS. 7 through 10. A pair of cutter halves 110 having a first cutter 112 and a second cutter 114 cut through the outer jacket 86 leaving only a thin web portion 116 intact. The outer jacket 86 is then stretched and a severed portion 118 i6 removed from the cords 52, 54 and 56. The individual cords 52, 54 and 56 then are 6tripped in the manner set forth above.
The foam-skin composite jacket multiple-lead cable 150 also may be stripped in a similar fashion, as may best be seen in FIGS. 17 through 20. A pair of cutter halves 210 having a fir~t cutter 212 and a second cutter 214 cut through the outer jacket 200, and cut substantially into the foam filler layer 190, leaving a portion of the foam filler layer 216 intact.
The outer jacket 200 and the foam filler layer 190 are then ~tretched, easily tearing the intact portion of the foa~ filler layer 216, and a severed portion 218 is removed from the cords 152, 154, and 156. The individual cords 152, 154, and 156 are then stripped in the manner set forth above.
It may be appreciated that the foam-~kin composite jacket multiple-lead cable is significantly easier to strip than conventional multiple-lead cables.
The foam filler layer has a lower tensile ~trength than the ~ame thickness of either paper and jute or 601id polyvinylchloride, therefore requiring less 2~ l 3 longitudinal force for ~tripping. The foam f$11er layer also 6eparates from the inner leads more easily than a ~olid polvvinylchloride outer jacket does, because the fosm void conten~ reduces the surface area of actual physical contact between the polyvinylchloride of the foam and the inner leads, thereby reducing frictional ~orces.
A particular advantage of the present invention lies ~n the fact that a single yarn of 1~ polyamide iB used in the fabrication of the instant invention, rather than multiple yarns which ~ust be bundled before the helical copper strands are wound thereabout. The single yarn of flexible polyamide fiber avoids the neces~ity of holding multiple yarns in proximity with each other while the multiple copper strands are wound thereabout. Thus, it may be appreciated that the instant invention provides a high strength electrical cable which may be easily 6tripped in a machine operation, but which remains flexible and 2~ easy to build.
While there has been illustrated and described a particular embodiment of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is attended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.
FIG. 1 i~ an isometric view of an electrical cable embodying the present invention;
FIG. 2 i~ a ~ection taken 6ubstantially along line 2--2 of FIG. 1 showing detail~ of the internal arrangement of the electrical cable;
FIG. 3 is an isometric view of an alternate embodiment of the electrical cable;
FIG. 4 i~ a 6ection taken substantially along line 4--4 of FIG. 3 showing detail~ of the internal arrangement of the electrical cable:
FIG. 5 is an i60metric view of another alternate embodiment of the electrical cable;
FIG. 6 is a section taken substantially along line 6--6 of FIG. 5 showing details of the internal organization of the electrical cable;
FIG. 7 is an isometric view of the cable of FIG. 6 positioned proximately with a pair of cutters, portions of which are shown;
FIG. 8 is an elevational view, partially in section, of the cable of FIG. 7 with the cutters engaging it;
FIG. 9 is an end view of the cable and cutters of FIG. 8;
FIG. 10 is an elevational view, partially in section, of the cable of FIG. 8 showing an outer ~acket being stripped off by the cutters:
FIG. 11 is an isometric view of the cable of FIGS. 1 and 2 positioned proximately with a pair of cutters, portions of which are 6hown;
FIG. 12 is an elevational view, partially in section, of the cable of FIG. 11 with the cutters engaging it;
FIG. 13 is an end view of the cable and cutters of FIG. 12;
FIG. 14 is an elevational view, partially in 2 f~
section, of the cable of FIG. 12 ~howing a jacket being stripped off by the cutters.
FIG. 15 is an lsometric view of yet another alternate embodiment of the ~lectrical cable;
FIG. 16 is a section taken suhstantially along line 6--6 of FIG. 15 showing detail of the internal organization of the electrical cable FIG. 17 is an isometric view of the cable of FIG. 16 positioned proximately with a pair of cutters, portions of which are shown;
FIG. 18 is an elevational view, partially in section, of the cable of FIG. 17 with the cutters engaging it;
FIG. 19 is an end view of the cable and cutters of FIG. 1~;
and, FIG. 20 is an elevational view, partially in section, of the cable of FIG. 18 ~howing an outer jacket being stripped off by the cutters;
Referring now to the drawings and especially to FIGS. 1 and 2, an electrical cable or flexible cord embodying the present invention and generally identified by numeral 10 is shown therein. The electrical cable 10 includes a single yarn, centrally located, circular cross section tensile strength member 12. The strength member 12 is comprised of a multi-filament 1500 denier polyamide yarn, coated with polyurethane, having a high modulus and of the type ~old under the designation Kevlar 29 or alternatively, Kevlar 49. The yarn has a diameter of 0.010-0.015 inches. A coating of polyurethane covers the polyamide yarn in order to prevent it from fraying.
Alternatively, nylon, varnish or epoxy coating could be -6~
used to prevent fraying of the polyamide yarn. It should be appreciated that the polyurethane fray resisting coating also meets Underwriters Laboratories 90C. temperature standards. A plurality of c~pper ~trands 14 is wound helically about the slngle yarn ~trength member 12. The plurality o~ copper strands 14 comprises between 41 ~nd 65 strands in the present embodiment. Each of the Rtrands 14 has a circular cross section. It may be appreciated that the strands 14 are wound about the single yarn stren7th member 12 without any intermediate filler or layered material such as paper, jute, and the like being interposed in between. The plurality of strands 14 contacts and substantially completely covers the single yarn strength member 12. Each of the strands 14 has a diameter in the range of Q.0050 inches or greater. In some embodiments of the present invention each of the copper strands may have a diameter of .010 inches. For such a strand diameter, only cixteen copper strands 2V would typically comprise the plurality. A
polyvinylchloride insulating jacket 16, having a circular cross section, i5 extruded over the plurality of copper strands 14 to 6ubstantially completely cover and enclose them.
Referring now to FIGS. 3 and 4, an alternative electrical cable 30 is shown therein. The electrical cable 30 includes a single yarn high modulus polyamide tensile strength member 32 having a 6ubstantially circular cross section. The polyamide 3~ strength member 32 is composed of Kevlar 29 or Kevlar 49 and has a diameter of 0.010-0.015 inches. A
plurality of copper conductor strands 34 is helically wound about each other and located adjacent to the 6trength member 32. The copper conductor strands 34 are each 0.0050 inches or greater in diameter. In the present embodiment, be~ween 41 and 65 strands are employed. A polyvinylchloride jacket 36 is extruded ~ !;
over the strength me~ber 32 and the conductor strands 34.
In a ~till further embodiment, as may be~t be seen in FIGS. 5 and 6, a multiple-lead cable 50 has a plurality of high 6trength cords 52, 54, and 56. Each of the cords 52, 54, and 56 is substantially identical to the cable lo s~own in FIGS. 1 and 2 and described above. The cord 52 has an inner polyvinylchloride ~acket 60 which is extruded over a single yarn polyamide tensile strength member 62 coated with polyurethans and a plurality of copper conductor strands 64 are disposed ~elically about and in contact with the strength member 62. The cord 5~ has an inner polyvinylchloride jacket 70 ~urrounding and contacting a plurality of helically wound copper conductor strands 72. A ~ingle yarn polyamide tensile strength me~ber 74 is coated with polyurethane and completely surrounded by and in contact with the copper conductor strands 72. The cord 56 has an inner polyvinylchloride jacket 80 having a plurality of copper conductor ~trands 82 helically wound inside thereof with a ~ingle yarn polyamide tensile strength member 84 coated with polyurethane and completely ~urrounded by and in contact with the plurality of copper conductors 82. An outer polyvinylchloride jacket 86 surrounds and contacts the inner jacket6 60, 70 and 80. The outer polyvinylchloride jacket 86 is extruded over the jackets 60, 70 and 80.
In a still further embodiment, as may best be seen in FIGS. 15 and 16 a foam-skin composite jacket multiple-lead cable 150 has a plurality of high strength cords 1S2, 154, and 156. Each of the cords 152, 154, and 156 ~s substantially identical to the cable 10 shown in FIGS. 1 and 2 and described above.
The cord 152 has an inner polyvinylchloride jacket 160 which is extruded over a single yarn polyamide tensile strength member 162 coated with polyurethane and a ~,~r~
plurality of co~er conductor strands 164 are disposed helically about and in contact with the strenqth member 162. The cord 154 has an inner polyvinylchloride ~acket 170 ~urrounding and contacting a plurality of helically wound copper conductor strands 172. A ~ingle y3rn polyamide tensile ~trength member 174 is co~ted with polyurethane and completely surrounded by and in contact with the copper conductor strands 172. The cord 156 has an inner polyvinylchloride ~acket 180 having a plurality of copper conductor strands 182 helically wound inside thereof with a ~ingle yarn polyamide tensile strength member 184 coated with polyurethane and completely 6urrounded by and in contact with the plurality of copper conductors 182. A polyvinylchloride foam filler layer 190 surrounds and contacts the inner jackets 160, 170, and 180. The polyvinylchloride foam filler layer is formed during the extrusion process by blending loO
parts polyvinylchloride with 1 part azo-dicarbonamide 2() type foaming agent at a temperature of about 200C, which is sufficient to activate the foaming agent and melt the polyvinylchloride but insufficient to destroy the polymer. The foam filler layer has approximately 35~ void content. An outer polyvinylchloride jacket 200 surrounds and contacts the polyvinylchloride foam filler layer 190. The outer polyvinylchloride jacket 200 is extruded over the foam filler layer 190. The polyvinylchloride foam filler layer 190 can have a thickness in the range of approximately 25-75% that oP
the thickness of the outer jacket 200.
It may be appreciated that the single yarn strength member provides a number of advantages to the users of the instant invention. The single yarn high modulus tensile strength member is flexible and provides high strength to the cord 10 allowing the cord to exceed the 170 pound tensile ~trength requirement set forth by Underwriters Laboratories and other 2 f ;
_g_ 6tandards-making organizations.
It may also be appreciated that the flexible cord with multiple leads surrounded by an outer jacket of foam and a non-porou6 ~kin provides a cord that is cheaper and lighter than a cord using Rolid polyvinylchloride and more flexible than a cord using paper or jute fillers. The foam filler layer uses less polyvinylchloride than the solid polyvinylchloride needed to fill the grooves betwee~ leads in the cord, so is therefore cheaper to produce and lighter in weight than an all-~olid polyvinylchloride csrd. ~he foam filler layer is also more flexible than the same thickness of solid polyvinylchloride or paper and jute fillers. The outer jacket of polyvinylchloride meets the non-porosity requirement for cable jackets as set forth by Underwriters Laboratories and other standards-making organizations.
Additionally, ~s may best be seen in FIGS. 11 through 14, the cable 10 may be quickly and easily stripped. A cutter 90 having a pair of mating cutter halves 92 and 94 may be used to strip the polyvinylchloride jacket 16 down to the copper ~trands 14. Since there is no intermediate layer, such as paper, jute, cotton or rayon, between the copper conductor strands 14 and the polyvinylchloride jacket 16, the jacket 16 need not be cut all the way through; a thin web portion 100 may be left. The remaining thin web portion 100 then i6 ~evered by stretching it, while the copper conductor strands 14 and the inner ~trength member 12 remain intact. A
severed portion 102 of the jacket 16 i~ then removed by 61 iding it off the copper conductor strands 14. In addition, the tensile ~trength member 12, since it is located within the helically wound strands 14, is unaffected by the ~tripping process; 60 that even when 6tripped of the outer jacket 16 down to the conductor strands 14, the cable 10 retains its high strength.
2~ '~ i 3 The cable 30, 8hown in FIGS. 3 and 4, also may be stripped down to the strength mem~er 32 and the copper strands 34 and the polyvinylchloride insulation 36 easily removed therefrom. Should it be desired, the tensile strength member 32 may then be separated from the conductor strands 34 to allow the conductor strand 34 to be fitted into relatively small connectors of the type used in electrical plugs to which they must be electrically connected.
The multiple-lead cable 50 also may be stripped in a similar fashion, as may best be 6een in FIGS. 7 through 10. A pair of cutter halves 110 having a first cutter 112 and a second cutter 114 cut through the outer jacket 86 leaving only a thin web portion 116 intact. The outer jacket 86 is then stretched and a severed portion 118 i6 removed from the cords 52, 54 and 56. The individual cords 52, 54 and 56 then are 6tripped in the manner set forth above.
The foam-skin composite jacket multiple-lead cable 150 also may be stripped in a similar fashion, as may best be seen in FIGS. 17 through 20. A pair of cutter halves 210 having a fir~t cutter 212 and a second cutter 214 cut through the outer jacket 200, and cut substantially into the foam filler layer 190, leaving a portion of the foam filler layer 216 intact.
The outer jacket 200 and the foam filler layer 190 are then ~tretched, easily tearing the intact portion of the foa~ filler layer 216, and a severed portion 218 is removed from the cords 152, 154, and 156. The individual cords 152, 154, and 156 are then stripped in the manner set forth above.
It may be appreciated that the foam-~kin composite jacket multiple-lead cable is significantly easier to strip than conventional multiple-lead cables.
The foam filler layer has a lower tensile ~trength than the ~ame thickness of either paper and jute or 601id polyvinylchloride, therefore requiring less 2~ l 3 longitudinal force for ~tripping. The foam f$11er layer also 6eparates from the inner leads more easily than a ~olid polvvinylchloride outer jacket does, because the fosm void conten~ reduces the surface area of actual physical contact between the polyvinylchloride of the foam and the inner leads, thereby reducing frictional ~orces.
A particular advantage of the present invention lies ~n the fact that a single yarn of 1~ polyamide iB used in the fabrication of the instant invention, rather than multiple yarns which ~ust be bundled before the helical copper strands are wound thereabout. The single yarn of flexible polyamide fiber avoids the neces~ity of holding multiple yarns in proximity with each other while the multiple copper strands are wound thereabout. Thus, it may be appreciated that the instant invention provides a high strength electrical cable which may be easily 6tripped in a machine operation, but which remains flexible and 2~ easy to build.
While there has been illustrated and described a particular embodiment of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is attended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.
Claims (16)
1. An electrical cable comprising: a plurality of insulated cords, each of said insulated cords comprised of: a single yarn tensile strength member, a plurality of conductors helically wound about and in contact with the single yarn tensile strength member, and an inner insulating jacket surrounding the helically wound conductors and the single yarn tensile strength member; a foam filler layer surrounding said plurality of insulated cords; and an outer insulating jacket surrounding said foam filler layer.
2. An electrical cable according to Claim 1, wherein said single yarn tensile strength member of each said insulated cord comprises a polymer.
3. An electrical cable according to Claim 1, wherein said single yarn tensile strength member of each said insulated cord comprises a polyamide.
4. An electrical cable according to Claim 3, wherein said plurality of metal conductors comprises copper.
5. An electrical cable according to Claim 4, wherein said outer and inner insulating jackets are comprised of a polymer.
6. An electrical cable according to Claim 4, wherein said outer and inner insulating jackets are comprised of polyvinylchloride.
7. An electrical cable according to any of Claims 1, 2, 3, 4, 5, or 6, wherein said foam filler layer is comprised of polyvinylchloride aerated during extrusion by mixing with azodicarbonamide foaming agent at about 200°C, which agent activates at that temperature to form a gas.
8. An electrical cable according to Claim 7, wherein said outer insulating jacket is in contact with said foam filler layer.
9. An electrical cable according to Claim 8, wherein the thickness of said foam filler layer extends approximately twice the thickness of the outer insulating jacket.
10. A method of making an electrical cable having a plurality of leads with strength members, surrounded by a foam filler layer and a non-porous outer jacket, comprising the steps of: helically winding a plurality of metallic conductors about each of a plurality of single yarn strength members;
extruding an inner jacket over each of said single yarn strength members wound with metallic conductors in the winding step; extruding a foam filler layer over said inner jackets; and extruding a non-porous jacket over said foam filler layer.
extruding an inner jacket over each of said single yarn strength members wound with metallic conductors in the winding step; extruding a foam filler layer over said inner jackets; and extruding a non-porous jacket over said foam filler layer.
11. An electrical cable comprising: at least one insulated cord comprised of: a single yarn tensile strength member: a plurality of conductors helically wound about and in contact with the single yarn tensile strength member of each said at least one insulated cord; an inner insulating jacket surrounding the helically wound conductors and the single yarn tensile strength member of said at least one insulated cord; a foam filler layer surrounding said at least one insulated cord; and an outer insulated jacket surrounding said foam filler layer,
12. An electrical cable according to Claim 11, wherein each said single yarn tensile strength member comprises a polyamide.
13. An electrical cable according to Claim 12 wherein said outer and inner insulating jackets are comprised of polyvinylchloride.
14. An electrical cable according to Claim 13 wherein said foam filler layer is comprised of polyvinylchloride aerated during extrusion by mixing with azodicarbonamide foaming agent at about 200°C, which agent activates at that temperature to form a gas.
15. An electrical cable according to Claim 14 wherein the thickness of said foam filler layer extends approximately twice the thickness of the outer insulating jacket.
16. A method of stripping an electrical cable having a plurality of cords, each comprising a tensile strength member helically wound with a plurality of metallic conductors and surrounded by an insulating jacket, a foam layer surrounding the plurality of cords and an outer jacket positioned around the foam layer, to prepare the electrical cable to be connected to a termination, comprising the steps of: cutting through the entire outer jacket and the foam layer of the electrical cable and leaving a thin web portion of the foam layer uncut surrounding the insulated jacket of the plurality of cords; and placing a tensile force across the web portion of the foam layer causing the web portion to part without severing a plurality of cords lying within the jacket.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/639,041 US5113039A (en) | 1989-05-04 | 1991-01-09 | Flexible cord with high modulus organic fiber strength member |
| US639,041 | 1991-01-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2058715A1 true CA2058715A1 (en) | 1992-07-10 |
Family
ID=24562491
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2058715 Abandoned CA2058715A1 (en) | 1991-01-09 | 1992-01-03 | Flexible cord with high modulus organic fiber strength member |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2058715A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017032417A1 (en) * | 2015-08-26 | 2017-03-02 | Leoni Cable Assemblies Slovakia S.R.O. | Electrical cable for an appliance, appliance and method for producing an electrical cable |
-
1992
- 1992-01-03 CA CA 2058715 patent/CA2058715A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017032417A1 (en) * | 2015-08-26 | 2017-03-02 | Leoni Cable Assemblies Slovakia S.R.O. | Electrical cable for an appliance, appliance and method for producing an electrical cable |
| US10643767B2 (en) | 2015-08-26 | 2020-05-05 | Bizlink Technology (Slovakia) s.r.o. | Electrical cable for an appliance, appliance and method for producing an electrical cable |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5113039A (en) | Flexible cord with high modulus organic fiber strength member | |
| US6570095B2 (en) | Multi-pair data cable with configurable core filling and pair separation | |
| US6246006B1 (en) | Shielded cable and method of making same | |
| US6300573B1 (en) | Communication cable | |
| KR100291656B1 (en) | Electric cables | |
| WO2016024544A1 (en) | Shielded wire | |
| US3717716A (en) | Plastic insulated conductor communications cable waterproofed with an internal void-filling mixture of petroleum jelly and high molecular weight polyethylene or polypropylene | |
| CN213211745U (en) | Medium-voltage flexible cable | |
| US2235523A (en) | Electric cord | |
| EP0567757B1 (en) | Cable for datatransfer and method for its manufacture | |
| US2119393A (en) | Electric cable and method of manufacturing the same | |
| CA2058715A1 (en) | Flexible cord with high modulus organic fiber strength member | |
| JP2017134925A (en) | Cable for signal | |
| RU47132U1 (en) | CABLE FOR COMMUNICATION, ALARM AND LOCKING SYSTEMS | |
| CN217239071U (en) | Low-voltage cable | |
| CN210349433U (en) | Circular net wire and net wire assembly thereof | |
| CN211654365U (en) | Towline cable containing power cable and network cable | |
| CN217740253U (en) | Shielded cable | |
| CN212161373U (en) | Flame-retardant fire-resistant high-performance twisted pair | |
| CN217361211U (en) | Rubber high-voltage cable with strippable outer screen | |
| CN214226550U (en) | Moisture-proof fluororesin insulation 2-core flat cable | |
| CN217134046U (en) | Cable for mobile equipment | |
| CN214956123U (en) | Medium-voltage waterproof power cable | |
| GB2046500A (en) | Electrical cables | |
| US3439112A (en) | Cable with molded strain relief and method of making same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |