US3668778A - Methods for joining ends of wires and the like - Google Patents

Abstract

A method for joining ends of wires and the like by means of an explosive charge. A connecting tube with a bore adapted to receive the ends to be connected is provided with an external layer of explosive charge having a varying geometrical shape longitudinally of said tube so as to produce after detonation alternating parts of different compression so that the contact surface between the tube and the ends therein after compression forms a more or less corrugated profile in the longitudinal direction in order to form an axially locked connection of the assembled components.

Description

United States Patent Lindtveit et al.

[ 51 June 13, 1972 [54] METHODS FOR JOINING ENDS OF WIRES AND THE LIKE [72] Inventors: Torleif Lindtveit, Minister Ditlefsvei l5; Leif Johnsen, Betzy Kjelsbergsvei 13, both of Oslo, Norway; Borge F. Haegland, deceased, late of Christian Michelsensgt. l6, Oslo, Norway by Marit Haegland, legal representative [22] Filed: April 3, 1969 [21] Appl. No.: 32,321

3,542,276 11/1970 James ..29/42l E 3,543,387 12/1970 Golinelli et 21.... ..29/421 E 3,417,455 12/1968 Pearson ..29/42l E Primary Examiner-John F. Campbell Assistant Examiner-Richard Bernard Lazarus Attorney-Stevens, Davis, Miller & Mosher This application filed under Rule 47a.

[5 7] ABSTRACT A method for joining ends of wires and the like by means of an explosive charge. A connecting tube with a bore adapted to receive the ends to be connected is provided with an external layer of explosive charge having a varying geometrical shape longitudinally of said tube so as to produce after detonation alternating parts of different compression so that the contact surface between the tube and the ends therein after compression forms a more or less corrugated profile in the longitudinal direction in order to form an axially locked connection of the assembled components.

5 Claims, 5 Drawing Figures METHODS FOR JOINING ENDS OF WIRES AND THE LIKE The present invention relates to a method for joining wires, rods, high tension lines and the like and for attaching end fastener thereto.

In connection with heavy gauge wires, which may be disposed in positions which are difficult to reach, commensurately high powered tools are required to make pressure connections between said wires. In view of the tools weight and bulk it may be inconvenient or impossible to carry such tools to the sites at which the joining is to be made.

It has previously been proposed to connect ends of wires and the like by inserting the ends into a corresponding bore of a connecting member provided with an external layer of explosive which during detonation compresses said connecting member around said ends. The layer of explosive used had, however an even cross-section in the whole length thereof in order to produce an even radial compression of the connecting member.

In connection with high tension lines, supporting cables and the like which are subjected to heavy stresses it is of great importance to obtain a clamping effect of the connecting member which insures that no relative sliding movement may occur between said member and the ends connected thereby.

According to the present invention this is obtained by an explosive charge surrounding the connecting member, in the longitudinal direction thereof. The member is formed with a varying geometrical shape so that after detonation of the explosive charge, the member has local areas which are compressed more than others.

The varying geometrical shape of the layer of explosive charge may-consist of a varying thickness in the longitudinal direction of the connecting member or the layer of explosive on the inner surface thereof may be provided with cavities, referably in the form of spaced circular grooves which roduce a hollow charge effect. This causes the connecting member as well as the ends below said grooves to be shaped with locally restricted cross-section alternating with partshaving a smaller restriction so that the interior dimensions of the connecting member after compression correspond to the external dimensions of the connected ends. Thus after compression necessary tensile strength is obtained due to the locking effect of said locally restricted cross-sections.

In using connecting members or tubes having relatively thick walls or consisting of soft or easily meltable metal such as aluminum, use is made of a damping material between the connecting tube and the explosive charge so that the surface of the connecting tube may resist the effect of pressure and heat from the amount of explosive which is necessary.

- According to the present invention the components for carrying the method into effect may be prefabricated according to a selected modulus, or be produced in sizes adapted to normal types of wires or conductors and joints. Thus the necessary components for a joint may be delivered in the form of a ready packaged unit, such as a solid wooden box distinctly marked, which is simple and easy to transport to any place of use. This unit would include connecting tubes having a ready dimensioned external explosive charge and appurtenant intermediate components, damping material etc.

For better understanding of the invention, reference will now be made to the accompanying drawing, in which:

FIG. 1 is a side view partially cut away with parts in section illustrating the core ends of a high tension line in a tube shaped connecting member.

FIG. 2 is a longitudinal sectional view of a main tube to be compressed over the core joint shown in FIG. 2.

FIG. 3 is a side view of the completed joint.

FIG. 4 is a longitudinal sectional view of filling members, and

FIG. 5 is a similar view of another filling members.

Referring now to the drawings in which as an example the principal steps of the method of joining a high tension line of the type having a steel core 4 and aluminum braiding conductors 5 are illustrated.

After stripping and preparing the line ends to expose the core ends 4, a main tube, to be later described in detail, is threaded onto one of the ends of the line. Thereafter the core ends 4 are inserted into a connector core tube or connecting tube 6. Tube 6 is made of steel and preferably galvanized, cleaned for any possible irregularities and thereafter coated with an external layer 7 of special plastic high explosive, which may be protected by an outer cardboard cylinder (not shown). Said explosive has a high specific weight and a relatively low detonation rate. Explosive charge layer 7 surrounding the core tube 6, has in its longitudinal direction, a varying geometrical shape in order to vary the compression effect in the longitudinal direction of the core tube. Said varying geometrical shape may have a varying thickness of the layer 7 or the layer on the inner surface thereof may be provided with cavities, preferably in the form of circular grooves 8 spaced at either even or uneven intervals.

In order to protect the end portions of the aluminum strands or braiding 5 against splitting etc. an axially split, tapered steel case, or shock conductor 10, as shown in phantom in FIG. 1, is clamped on each of said ends by means of screws or the like and then the explosive charge 7 is detonated by means of a detonator 9 which may be of any conventional type.

Core tube 6 during the detonation is exposed to an external pressure impulse, the culminating pressure progress and duration of which are dependent of upon the type, amount and geometry of said charge. Due to the grooves 8 of the layer 7 the hollow charge effect thereof produces parts having locally restricted or narrowed cross-sections in the core tube 6 as well as in the core 4 therein, alternating with parts having smaller restriction and so that the contact surface between the tube and the core ends therein after compression forms a more or less corrugated profile in the longitudinal direction.

The arrangement of joining the whole cross-section of the line is illustrated in FIG. 2.

After detonation the cases .or shock conductors 10 are removed. If the core tube 6 is of smaller diameter than that of the conducting strands 5 use is made of filling members. Firstly the exposed core portions between the ends of the tube 6 and adjacent ends of the conductors are each covered with a pair of tube halves l2, 12, FIG. 4, having an outer diameter substantially corresponding to that of the core tube 6. Further the core tube 6 is provided with an enclosure comprising two half tubes l3, 13, FIG. 5, having an outer diameter substantially corresponding to the outer diameter of the braided conductors 5, and a length to cover both the core tube and the halves l2, 12 at the ends thereof. Said tube halves l3, 13 are made of aluminum, while the tube halves 12, 12 aremade of zinc and serve in addition as anodes which protect both the steel and aluminum against corrosion. The final compact joint allows very little internal circulation of air and moisture and in addition the enclosed zinc anodes give the minimum deadvolume a maximum of corrosive protection.

After the tube halves l2, l2 and l3, 13 are mounted and fastened in position by means of tape or the like the main tube 14 is pushed into position over the core joint. The main tube consists of aluminum and has a relatively great wall thickness, and in order to protect the surface of said tube against melting and crater forming it is preferred in this case to use between the main tube 14 and the explosive charge an intermediate layer of elastomeric damping material, such as a hose 15 of plastic, rubber or similar plastic deformable material, threaded on said tube 14. In the present case the explosive charge consists of detonating fuse l6 wound spirally around said hose 15. In order to obtain the preferred varying geometrical shape the fuse 16 may be wound possibly with varying pitch in one layer or partially in two layers.

In addition to the above named protection of the surface of the main tube 14 said intermediate layer (hose) 15 may be given a varying thickness in order to regulate the effect of the detonation impulse. In detonation of the explosive charge 16 the main tube 14 is compressed in a predetermined manner about the ends of the conductors 5 and the core tube 6, possibly via filling members l2, l3 and thereby the joint is finished, as shown in FIG. 3.

We claim:

I. A method of joining the ends of two cables each having a central core and conductor strands surrounding the core comprising:

a. stripping said cables so that the core ends project beyond the conductor strand ends;

b. inserting said core ends into a connecting tube having an external explosive layer;

c. detonating the explosive to compress the connecting tube around the core ends;

d. placing a second tube over both said connecting tube and the conductor strands;

e. providing said second tube with a layer of explosive;

f. placing an intermediate layer of plastic deformable material between the explosive layer and the second tube;

g. detonating the explosive layer over the second tube so as to compress the second tube around the connecting tube and the conductor strands, the compression varying over the length of the second tube and the strands in dependence upon the shape of the explosive layer thereover and the type and thickness of the intermediate layer.

2. The method of claim 1 including the steps of placing a protective case over the conductor strand ends prior to detonation of the connecting tube explosive and removing said casing prior to placing said second tube over the strands.

3. The method of claim 1 including the step of placing a filling member over the connecting tube after detonation of its explosive layer to fill the gap between the outside diameter of the strands and the outside diameter of the connecting tube.

4. The method of claim 3 including inserting split fillers between the connecting tube and the strand ends prior to placing the filling member thereover.

5. The method of claim 1 including placing said explosive layer in varying geometrical shape in the longitudinal direction of the connecting tube and strands so as to vary the compression effect.

Claims (5)

1. A method of joining the ends of two cables each having a central core and conductor strands surrounding the core comprising: a. stripping said cables so that the core ends project beyond the conductor strand ends; b. inserting said core ends into a connecting tube having an external explosive layer; c. detonating the explosive to compress the connecting tube around the core ends; d. placing a second tube over both said connecting tube and the conductor strands; e. providing said second tube with a layer of explosive; f. placing an intermediate layer of plastic deformable material between the explosive layer and the second tube; g. detonating the explosive layer over the second tube so as to compress the second tube around the connecting tube and the conductor strands, the compression varying over the length of the second tube and the strands in dependence upon the shape of the explosive layer thereover and the type and thickness of the intermediate layer.

2. The method of claim 1 including the steps of placing a protective case over the conductor strand ends prior to detonation of the connecting tube explosive and removing said casing prior to placing said second tube over the strands.

3. The method of claim 1 including the step of placing a filling member over the connecting tube after detonation of its explosive layer to fill the gap between the outside diameter of the strands and the outside diameter of the connecting tube.

4. The method of claim 3 including inserting split fillers between the connecting tube and the strand ends prior to placing the filling member thereover.

5. The method of claim 1 including placing said explosive layer in varying geometrical shape in the longitudinal direction of the connecting tube and strands so as to vary the compression effect.

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