Electrical Cable

Abstract

A wire rope contains one or more electrically conductive wires running along within a core strand, the conductive wires being surrounded by insulation which is in turn covered by a helically wound closely spaced crush-resistant armor wire.

Parent Case Text

This application is a division of our copending application, Ser. No. 822,334, filed Jan. 21, 1969 now U.S. Pat. No. 3,560,631, which is a division of application Ser. No. 621,337, filed Mar. 7, 1967, now U.S. Pat. No. 3,482,034, for "Fishing Net Assembly Including Towing Cable Having A Conductor Included Therein With Break-Out Means For The Conductor And Fish Shocking Cable."

Description

This invention relates to metal cables, and more particularly to preformed wire rope having high tensile strength while at the same time carrying one or more wires having high electrical conductivity.

One object of the invention is to provide a high strength, flexible, wire cable, wherein an electrical conductor or conductors are included in one or more of the strands.

Another object of the invention is to provide a seven strand high strength wire cable wherein the core includes a electrical conductor.

Other objects and advantages will be apparent to those skilled in the art after reading the following specification in connection with the attached drawings, in which:

FIGS. 1, 2 and 3 are cross-sections of three forms of combined electrically conducting and load bearing ropes.

FIG. 4 is a cross-section of core which can be used in the ropes shown in FIGS. 1-3.

FIG. 5 is a side view of a section of the core shown in FIG. 4. And,

FIGS. 6, 7 and 8 are cross-sections of various armor wires used in FIGS. 4 and 5.

Both FIGS. 1 and 2 show cross-sectional arrangements of single conductor towing cables suitable for use as a towing rope, and in this connection it should be noted that the use of the term "single conductor" is intended to indicate only that a single strand of the rope is utilized for the transmission of electrical energy although there may be more than one electrical wire contained within that single strand. In the form shown in FIG. 1, the cable is a seven strand cable having six outer strands, indicated generally by numerals 39, each of which may comprise seven steel or other high tensile strength metal wires, these six strands being helically wound about a core, indicated generally by numeral 40.

The core is composed of one or more copper, aluminum or other electrically conductive wires 41 which may, or may not, be electrically insulated from each other, in the drawing they are bare wires forming a single conductor. This inner group of conductors may be surrounded with an insulating jacket of polyethylene or polypropylene or other similar material 42 and, in addition, this coating may be surrounded with a jacket of braided rayon 43 which, in turn, may be covered with a coating of nylon 44 with a final armor covering composed of twelve steel or other wear-resistant metal wires 45. In this connection, it should be noted that the lay of the armor wires 45 should be opposite to the lay of the outer strands 39, for example, if the outer strands are preformed with a right-hand lay, the inner wires should be preformed with a left-hand lay. Such an arrangement distributes radial pressures incident to winding in multiple layers on small drums and small diameter shenves.

The form of single conductor cable shown in FIG. 2 differs somewhat from that of FIG. 1 although it still basically comprises a seven strand cable having six outer strands, indicated generally by numerals 46, of high tensile steel or other similar material surrounding a core, indicated generally by numeral 47, which in turn is composed of one or more central electrically conductive filaments 40. In this case the conductors may also be surrounded with a polypropylene or polyethylene coating 49 covered in turn by a rayon braided jacket 50 which itself is coated with a nylon plastic 51. In this case the armor comprises fifteen wires 52 and, as in the case of the previous form of cable, if the outer strands 46 are preformed with a right-hand lay the armor wires 52 should be preformed with a left-hand lay.

FIG. 3 discloses another modified form of seven strand cable having an electrically conductive core similar to the cable shown in FIGS. 1 and 2 and in this form the six outer strands of high tensile steel are indicated by numeral 60, surrounding a core, indicated generally by numeral 61, which may include one or more central electrically conductive filaments 62 surrounded by an insulating coating 53 of polypropylene or polyethylene preferably covered by a braided rayon jacket 64 which may, in turn, be coated with nylon plastic 65. In this modification the core is completed by surrounding it with nine preformed helically wound armor wires 66 and, as in the case of the previous modification, these should be of the opposite lay to the lay of the outer strands 60 which are themselves preferably preformed. The advantage of this modified form over those shown in FIGS. 1 and 2 is that with a lesser number of armored wires their diameters may be increased thus increasing the amount of resistance to crushing. The forms of electrically conductive wire rope described above are disclosed and claimed in the parent application, Ser. No. 621,337, filed Mar. 7, 1967, now U.S. Pat. No. 3,482,034.

In FIGS. 4 and 5 another type of core member is shown which it has been found is especially resistant to crushing stress. In the drawings, only the core member has been shown and it will be understood that this core member may be substituted for the core member shown in FIGS. 1, 2 and 3 to make up a seven strand wire rope whose outer strands are preformed from high tensile steel as in the previous modification shown. In this type of core the electrically conductive wire 67 may be surrounded with a coating of insulating plastic material 68 having a braided synthetic fabric covering 69 surrounded by another synthetic plastic insulating material 70, around which may be wrapped a single helically wound armor wire 71 which is closely spaced as seen in FIG. 5. While in the figure the armor wire 71 is indicated as having a circular cross-section, it will be understood that it might be formed with an elliptical or even a rectangular cross-section as indicated by numerals 72 and 73, in FIGS. 6 and 7. Also, as in FIG. 8, there may be more than one armor wire, such as wires 74 and 75, wound closely together around the insulating material 70. Due to the fact that each complete turn of the armor wires 71, 72, 73, 74 and 75 lies almost in a transverse plane, it offers the greatest amount of resistance to radially inwardly directed forces directed against the other strands. Also, this nearly transverse arrangement of the turns means that it is not as important that the lay of the outer strands be opposite to that of the lay of the single armor wire surrounding the core because the resultant of the interacting forces between the armor wire and the wires of the outer strands do not exert any appreciable tendency to unravel the armor wire regardless of the direction of their respective lays.

Having disclosed several forms in which the invention may be practiced, it will be evident to those skilled in the art that various modifications and improvements may be made which would come within the scope of the annexed claims.

Claims

1. A wire towing rope having an electrically conductive core, comprising a seven strand cable, the six strands surrounding the core strand being preformed of high tensile strength metal wire filaments, the core strand including at least one filament of electrically conductive metal having low tensile strength compared to the tensile strength of said surrounding strands, a non-conductive covering surrounding and embedding said one filament, and at least one helically wound closely spaced crushing-resistant armor wire surrounding said non-conductive covering to

2. The invention as defined in claim 1, wherein the cross-section of said

3. The invention as defined in claim 1, wherein the cross-section of said

4. The invention as defined in claim 1, wherein there are a plurality of closely spaced armor wires wound in a single layer about said non-conductive covering, each turn of said armor wires lying substantially in a transverse plane.