US2759990A

US2759990A - Electrical conducting ropes

Info

Publication number: US2759990A
Application number: US267585A
Authority: US
Inventors: Bean Reginald
Original assignee: Pirelli General Cable Works
Current assignee: Pirelli General Cable Works Ltd; Pirelli General Cable Works
Priority date: 1951-01-23
Filing date: 1952-01-22
Publication date: 1956-08-21
Anticipated expiration: 1973-08-21
Also published as: BE508636A; FR1049791A

Description

Aug. 21, 1956 R. BEAN ELECTRICAL CONDUCTING ROPES Filed Jan. 22, 1952 2 Sheets-Sheet 1 INVENTOR K I LD Bmy C) TTO NGY Aug. 21, 1956 R. BEAN 2,759,990

ELECTRICAL CONDUCTING ROPES Filed Jan. 22, 1952. 3 Sheets-Sheet 2 INVEN R Ptiuv 34D 9M QTTORNEY United States Patent 2,759,990 ELECTRICAL CONDUCTING ROPES Reginald Bean, Southampton, England, assignor to The Pirelli-General Cable Works Limited, London, England Application January 22, 1952, Serial No. 267,585

Claims priority, application Great Britain January 23, 1951 9 Claims. (Cl. 174-69) This invention relates to ropes and particularly to ropes of the kind incorporating an insulated electric conductor or conductors. Such ropes are used in the electric killing of whales and may also be used as towing ropes for say gliders where the electric conductor or conductors serve for telephone connections between the glider and a towing plane.

In the electric killing of whales, a harpoon is generally attached to what is known as a forerunner and the forerunner may itself be attached to a main rope of say nylon or manila although, in some cases, the main rope may be dispensed with. Both the forerunner and the main rope incorporate at least one insulated extensible electric conductor which must, of course, lengthen and contract to the same extent as the forerunner or main rope. An electric generator provides current through the line for electrocuting a whale using the sea as an earth return, and one known form of insulated conductor for incorporation in a forerunner or main rope consists of a rubber core, a braided conductor of tinned copper wire on this core, a rubber sheath over the wire, and an open textile braiding or whipping of say flax over the rubber sheath to link the sheath and thereby the conductor to the strands of the forerunner or main rope. Such an insulated conductor will lengthen and contract together with the forerunner or rope, which may have an extension of up to 40%, without damage to the conductor and Without falling free of the strands of the rope.

As is well known, the forerunner must be as light as possible and difficulty has been experienced in producing a small rope for an electrified forerunner which does not suffer from the trouble of strangulation of the incorporated insulated conductor and breakage of the electric circuit when the forerunner is stretched a few times. With known types of forerunner, as the forerunner is stretched so the strands thereof twist and clamp down on the conductor. Several successive pinchings of the conductor harden the wires thereof and finally break them. In addition to the crushing action or strangulation of the conductor, localised break-up of the fine wires may occur as a result of undue elongation of the wires caused by excessive torque.

One object of the an electrified avoided.

According to one aspect of the present invention, in a rope of the kind incorporating at least one insulated electric conductor, the electric conductor is enclosed within a plurality of concentric flexible layers and the arrangement is such that the tendency of one layer to twist and so strangle the conductor when the rope is longitudinally stressed is neutralised or substantially neutralised by an adjacent layer of the rope.

The said flexible layers may each consist of closely adjacent strands of suitable textile material such as manila or nylon, adjacent layers being laid on in opposite senses. Thus, if an insulated electric conductor of the nature described above is used as a central core, then present invention is the provision of forerunner in which these troubles are the first layer of strands would be applied or wound on say in a clockwise or right-hand direction (looking along the rope), the next outer layer in an anti-clockwise or left-hand direction, the next in a. clockwise direction and so on. The layers may be enclosed in a braided sheath of say manila or nylon strands.

In order that the invention may be clearly understood, two constructions of electrified forerunners or ropes for electric whaling and in accordance with the present invention will now be described by way of example with reference to the two figures of the accompanying drawing in which Figure 1 shows a stripped back or telescoped front elevation of one construction and Figure 2 shows a similar elevation of the second construction. For simplicity, like parts in the two figures have been given the same reference numerals.

Referring now to Figure 1; the rope comprises an insulated electric conductor 1 as described above which forms a central core of the rope. The conductor 1 comprises a rubber core 2 of circular section, the braided wires 3 of tinned copper, a rubber sheath 4 over the wires 3, and an open braiding or whipping 5 of flax or cotton over the sheath 4. Laid on the conductor 1 are four stranded hemp or manila layers 6, 7, 8 and 9 and a final outer braided layer 10 of hemp or manila. The layers 6 to 10 may be put on with standard electric cable making machines and may be impregnated with oil or other suitable water repellant materials. The stranded layers 6 to 9 are laid on so that adjacent layers are of opposite sense and the arrangement is such twist, it is neutralised by an adjacent layer.

The two innermost layers 6 and 7 neutralise one another and each of these layers has the same number of individual strands, for example, sixteen. 8 and 9'also neutralise one another and each of these layers has the same number of strands, for example, twentyfour. All the strands of the layers 6 to 9 are wound to give as close a covering as possible, and, in winding on the strands of all the layers, a constant angle of inclination of the strands to the axis of the rope is maintained. This means, of'course, that the strands of the outermost layer 7 or 9 of a pair of layers 6 and 7 or 8 and 9 do not cover so closely as that of the innermost layer 6 or 8 of the pair but it ensures that each layer takes the required proportion of the load and twist is balanced out to prevent strangulation and breakage of the insulated conductor 1.

Many materials are, of course, suitable for use for the separate strands in the layers. Hemp, manila and nylon are particularly suitable but materials such as cotton, sisal, flax, jute, silk, rayon, etc. may be used. A rope using nylon is shown in Figure 2 and, referring to this figure, the rope comprises an electric conductor 1 as before with its constituent parts 2 to 5 although in this case the open braiding 5 is of nylon cord. Laid over this open braiding 5 are six concentn'c layers of nylon stranded cord 11 to 16 and over the last layer 16 is a braided layer 17 of nylon cord. The pairs of

layers

11 and 12, 13 and 14, and 15 and 16 neutralise one another, the number of strands in any pair of layers being the same, and in the example shown, the pairs of layers have twenty, thirty and forty-one strands per layer, the layers 15 and 16 having the forty-one strands. Naturally, the number of strands in the pairs of layers may be varied and the first pair of layers 11 and 12 may consist of six or sixty instead of twenty strands.

It is not necessary, in either construction described, for the final outer braided layer 10 or 17 to be of the same textile as the inner layers. The purpose of this braided layer is to give the rope a smooth relatively even finish and also to hold the inner layers together in their relative Patented Aug. 21, 1956;

that if one layer tends to The two outermost layers positions, so preventing any tendency on the part of the electric conductor 1 to migrate from the centre of the rope. The layer carries very little, if any, of the load on the rope when under tension although, if desired, it could be designed to carry a proportion of the total load. The proportion can be kept small by making the angle of the braid strands to the axis of the rope considerably greater than the angle of the strands of the inner layers to the axis.

The necessary rope strength and electrical conductivity can be achieved by suitable choice of the electric conductor 1 and the sizes and number of layers of textile over the conductor but, in some cases, a composite electric rope may be made by including say three ropes as described above with reference to either Figure 1 or 2 in a single stranded whole.

In the two ropes described above with reference to Figures 1 and 2, the various layers of hemp, manila or nylon are made up from a plurality of strands or cords which are themselves made up from several smaller strands, for example, three smaller strands twisted together. The unit cords or strands of all the layers in a rope may all be made up from smaller strands twisted in the same direction, that is, the same cord may be used for all strands of all layers or the unit cords or strands in balancing layers, for example layers 6 and 7 in Figure 1, may have opposite twists. Thus, the cords or strands in the layer 6 may be made up from three smaller strands twisted with a right-hand lay and the cords or strands in the layer 7 may be made up from three smaller strands twisted with a left-hand lay. The direction of lay or twist of the smaller strands of a unit cord or strand may or may not be the same as the direction of lay or twist of the layer of cords or strands in which the unit cord or strand lies.

I claim:

1. An extensible rope constituting an electric conductor comprising a central core of extensible insulating material, an extensible winding of electrically conducting wire mounted upon said core, an extensible insulating sheathing of material over said extensible winding, an open braiding of textile material over said extensible insulating sheathing, a plurality of pairs of concentric load carrying stranded layers of textile material such as nylon over said open braiding, the layers of each of said pairs having the same number of strands and being laid on in opposite senses to give a balanced construction, strands of all the pairs of layers having a constant angle of inclination to the rope axis, and an outer covering layer of textile braiding.

2. An extensible rope as claimed in claim 1, wherein the central core and the insulating sheathing are of material such as rubber.

3. An extensible rope as claimed in claim 1, wherein the extensible winding of electrically conducting wire consists of a braiding of tinned copper wires.

4. An extensible rope as claimed in claim 1, wherein the strands of all the pairs of layers have a constant angle of inclination to the rope axis.

5. An extensible rope as claimed in claim 1, wherein the outer covering layer is adapted to carry a proportion of the total load on the rope.

6. An extensible rope as claimed in claim 1, wherein each of the strands of all the pairs of layers consists of several smaller strands twisted together and the direction of twist of said smaller strands in the main strands of one layer of a pair of layers is the same as the direction of twist of said smaller strands in the main strands of the other layer of the said pair of layers.

7. An extensible rope as claimed in claim 1, wherein each of the strands of all the said pairs of layers consists of several smaller strands twisted together and the direction of twist of said smaller strands in the main strands of one layer of a pair of layers is opposite to the direction of twist of said smaller strands in the main strands of the other layer of the said pair of layers.

8. An extensible rope as claimed in claim 1, wherein each of the strands of all the pairs of layers consists of several smaller strands twisted together and the direction of twist of said smaller strands in the main strands of a layer is the same as the direction of twist of the said main strands.

9. An extensible rope as claimed in claim 1, wherein each of the strands of all the pairs of layers consists of several smaller strands twisted together and the direction of twist of said smaller strands in the main strands of a layer is opposite to the direction of twist of the said main strands.

References Cited in the file of this patent UNITED STATES PATENTS 887,160 Webb May 12, 1908 2,087,303 Rosch et al. July 20, 1937 2,092,532 Hollenweger Sept. 7, 1937 2,175,389 Hanff 1. Oct. 10, 1939 2,587,117 Clay Feb. 26, 1952 FOREIGN PATENTS 5,592 Australia Jan. 5, 1932 418,668 Great Britain Oct. 22, 1934 980,422 France May 11, 1951