JPS5810932B2 - Method and assembly for protectively insulating electrical wire connection parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an assembly for protecting and insulating connections between electrical wires.

It is often necessary to insulate and protect the connections of electrical wires, such as electrical cables.

Many problems arise when attempting to connect cables, such as telephone cables or power cables, in the field.

This is due to the need to provide continuity for insulation and grounding, to make connections water resistant and protected from various chemicals, and to provide mechanical strength and resistance to tension, compression, deflection and impact. be.

For example, British Patent No. 1,155,470 describes the use of sleeves or tubes of heat-shrinkable material with or without longitudinal cuts to protect and insulate electrical cable connections. Proposed.

The sleeve has a suitable diameter in its initial, stressed state, is easily moved into position, and contracts to fit tightly over the connection when heated. It is now possible to match.

Since cables often need to be pressure and water resistant, it is necessary to coat the inner wall of the heat shrink sleeve with a sealing compound, such as frankincense or hot melt adhesive.

Heating the sleeve melts the sealing compound and forms a water and pressure resistant seal between the sleeve and the cable.

A disadvantage of this type of protective sleeve for enclosing the connection part is that in some cases it cannot be opened easily when repairs or modifications are to be carried out, for example when inserting additional cables. The entire connection part must be renewed.

British Patent No. 1,248,908 discloses a method for connecting electrical cables using a bridge sleeve made of non-heat-shrinkable material and an end sleeve made of heat-shrinkable material, said sleeves being connected by screws, for example. interconnected.

Such an assembly unit is positioned such that the bridge sleeve lies over the connecting portions of the cables and each cable is surrounded by one of the end sleeves.

The connections are then sealed by heating the end sleeves so that they contract over and grip each cable.

Such devices require relatively tight manufacturing tolerances to allow easy engagement of the male and female threads on the bridge sleeve and the end sleeve.

The present invention provides an assembly for protecting and insulating the connecting portion of electrical wires, particularly cables, comprising a relatively rigid split tube having a diameter and an axial split adapted to the connecting portion and providing a relatively rigid support. a split tube supported at each end by means; a heat shrink sleeve surrounding the split tube extending over the entire length of the split tube and the supporting means and capable of contacting the electrical wire at each end; at least the end of the sleeve has a sealing material on its inner wall;
The present invention provides an assembly in which the diameter of the contracted sleeve changes continuously between the diameters of the split tube and the wire when the assembly is assembled.

Preferably, the support means for the split tube are two relatively rigid rings having substantially the same diameter as the split tube when the split tube is positioned within each end of the sleeve.

These rings may or may not extend beyond the ends of the split tubes when in place.

The central section of the sleeve, which contracts over the split tube, does not seal the split tube or does so to a minimum extent.

This is done, for example, by suitably selecting the sealing material or the surface properties of the split tubes.

It should be noted that only the end sections of the heat shrink sleeve are coated with a sealing compound, such as frankincense or hot melt adhesive, leaving a central section of length substantially equal to the length of the split tube uncoated so that shrinkage occurs. Sometimes only the coated end of the sleeve is shrunk onto and bonded to the wire (over the support ring when deemed appropriate), while the uncoated central section is left uncoupled onto the split tube. It is made to shrink.

The heat shrink sleeve can be of a circumferential type with longitudinal cuts, if desired.

The sleeve is then provided with sealing means along the cut, such that a water- and pressure-tight connection is obtained after shrinking.

The split tubes of relatively rigid material can be formed by conventional half-cylinders, which are connected (or not) by hinge devices.

Note that the tube can be formed with a single split or with two members of different sizes.

The joint covering assembly according to the present invention can be easily opened by cutting the central portion of the heat shrink sleeve to allow repair or modification of the joint.

The split tube can then be easily removed if it is not sealed against the shrink sleeve.

If a seal is provided, the seal strength can be reduced if necessary by heating the assembly to the softening point of the sealing material.

After repair or modification, the split tube is put back into place and the connection is resealed, for example by a surrounding heat shrink sleeve with a notch.

The inner wall of the sleeve is coated with a sealing material and is adapted to seal the notch and form a water-tight and pressure-tight connection.

A closure member such as that described in GB 1,155,470 is particularly suitable.

The material of the split tube may be such that at least its outer surface does not bond with the selected sealant on the surrounding sleeve, allowing the connection to be reopened during subsequent repairs or alterations. desirable.

When connecting cables, it may be necessary to add a new cable to the connection section in some cases.

This can be easily accomplished by providing the shrink sleeve with a notch along its entire length so that it can be removed in its entirety.

The sealed end section can be removed by heating it to soften the sealing compound.

The split tube and support are then removed, a new cable is inserted and the whole is wrapped with sealing tape.

After refitting the split tube and support, the new connection is covered with a notched, surrounding heat-shrinkable sleeve, for example a closure of the type described in British Patent No. 1,155,470.

In a preferred embodiment of the assembly according to the invention, said split tube is provided with a plurality of relatively flexible large protrusions, said protrusions being spaced apart around said tube and stacking the tube. projecting longitudinally beyond at least one end (preferably each end) of the tube, and being attached to or integrally formed with said support means, further comprising said heat shrinkable sleeve extending beyond the total length of said tube, said support means and said protrusion. is also formed to have a large length.

In this embodiment, when heat is applied to the sleeve of heat shrinkable material, the central section surrounding the split tube contracts slightly to firmly grip the tube.

The reason for this is that the rigidity of the supported tube is relatively large.

The section of the sleeve surrounding the projection is subject to progressive contraction from the end of the tube towards the end of the projection.

The reason for this is that the protrusion tends to deform progressively towards its end, and near the end the sleeve contracts tightly against the wire.

The provision of such protrusions allows the sleeve to smoothly taper in diameter from the large diameter section surrounding the split pipe to the small diameter section surrounding the wire, thereby reducing stress on the sleeve material. This can be reduced and the section of varying diameter can be reinforced by the protrusion.

If only the end section of the inner wall of the heat shrink sleeve is to be sealed with a sealant, the section from the end of the tube to a point approximately midway along the length of the projection is suitably covered.

The central section, which is slightly longer than the split tube and the support, is therefore uncoated and, in the event of shrinkage, the covered ends of the sleeve are exposed to the projections, wires and, if a support ring is used, The support ring is contracted and the uncoated central section is contracted onto the split tube.

The protrusion may be formed integrally with the support means for the split tube, or it may be a separate assembly fixed to the support device, for example by soldering.

It is desirable that the protrusion is not attached to the split tube itself.

The reason for this is that if installed in this way, the split pipe will not be able to open during repairs or the like.

The projections form part of a contour or "comb" in which they are integrally formed with the band part.

In preferred embodiments in which the support ring is positioned at each end of the split tube, the strip forming the base of the protrusion can be soldered to the support ring.

The protrusion may be suitably made of aluminum, which has high strength, light weight, and flexibility.

The protrusions should be tapered towards their ends, so that their deformability gradually increases towards their free ends.

The tube with longitudinal splits and the support can be made of suitable materials, such as metal, hard rubber or synthetic materials, such as polyethylene, in particular high-density polyethylene, which may contain the usual additives (fillers, pigments, etc.). , flame retardants, antioxidants, etc.).

If the connection is to be made in the power cable, the material should be irradiated as much as possible so that it does not melt in the event of an overload.

Other suitable plastic materials include polyvinyl chloride and polypropylene.

The tube can be made of electrically insulating, semiconducting or electrically conductive material as required.

The heat shrink sleeve may be made of a suitable material, for example British Patent No. 99
0,235 and 1,062,043.

Said tube is preferably formed from a polyolefin, preferably polyethylene crosslinked by chemical means or by irradiation and containing customary additives (fillers, flame retardants, antioxidants, etc.).

The present invention also provides a method for coating a connection between electrical wires, in particular electrical cables, comprising a relatively rigid tube provided with relatively rigid support means as described above and having a longitudinal cut above said connection. positioning the assembly;
shrinking a heat-shrinkable sleeve having a length greater than the length of the split tube provided with the support means over the connecting portion surrounded by the support stepped tube; At least a portion of the inner wall of the sleeve has a sealing material, the end section of the sleeve contracted over the wire seals the wire when the sleeve is contracted, and the center of the sleeve contracted over the split tube. A method is provided in which the compartments do not seal off the branch pipes.

If the support means for the split tube have two closure rings, it is necessary to position the rings on the wire before forming the connection part.

However, it is also possible to use an opening ring with a closing device.

In this case, after the ring has formed the connection, it is positioned over the wire without passing it along the length of the wire, and then it is closed.

The support means should be rigidly connected to the split tube, for example by a bayonet fitting, so that the support device and the split tube do not move relative to each other when the shrinking process takes place.

This is particularly desirable when the assembly is provided with projections and it is to be ensured that the optimal position of said projections is maintained when retraction takes place.

The present invention further provides relatively rigid split tubes, relatively rigid support means, heat shrink sleeves, and optionally protrusions for use in assemblies of the present invention.

The present invention will now be described in detail with reference to the accompanying drawings.

The assembly as shown in FIG. 1 consists of a heat-shrinkable sleeve 1 and a relatively rigid, longitudinally split tube 2 formed by two semi-cylinders 3, 3a and of which It is supported by relatively rigid support rings 4 located at both ends.

The support ring can be attached to the tube 2, for example, by means of a bayonet-type fitting (see FIG. 8).

The inner wall of the sleeve 1 is coated with a sealant 5 only in its end sections 6-6'.

FIG. 2 shows the assembly in the position on the connection part 7 between the electrical cables 8 and with the sleeve 1 in the retracted state.

The inner diameter of the split tube 2 is selected to match the outer diameter of the connecting part 7.

The sealant 5 is for sealing the connection against water and pressure.

FIG. 3 shows the connection opened in the central section 9-9' and sealed again by a heat-shrinkable split sleeve 10 having a sealant 11 on the inner wall.

In the assembly of FIG. 2, when repairing or inspecting the connecting part 7, the sleeve 1 is cut away along the line 9--9'.

After completion of the repair or inspection, a heat-shrinkable split sleeve 10 with a sealant 11 is placed over the split tube 2 exposed by the removal of sections 9-9'.

Split sleeve 10 is closed by flexible rail 12 and contracted to seal the gap between lines 9-9'.

FIG. 4 shows the connection assembly opened over its entire length and with the sleeve 1 completely removed.

The connecting part is sealed again by a heat-shrinkable split sleeve 13 extending along the entire length originally occupied by the sleeve 1.

The split sleeve 13 is closed by a flexible rail 14.

FIG. 5 shows a comb 15 consisting of a plurality of flat parallel projections 16 extending from a monolithic band 17.

The projection tapers towards its end 18.

In FIG. 6, the comb 15 is fixed to the ring 4 by soldering the band 17 to the outer surface of the ring 4.

The heat shrink sleeve 1 surrounding the assembly is formed to be larger than the combined length of the tube 2, ring 4 and projection 16.

The end section 6 of the inner surface of the sleeve 1 is covered with a sealing material 5 up to approximately the midpoint of the length of said projection 16.

FIG. 7 shows the position in which the connecting portion 7 between the wires 8 is surrounded by the assembly shown in FIG. 6 and the sleeve 1 is in the retracted state.

The end section 19 of the sleeve 1 contracts against the wire 8 and compresses the protrusion 16.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an assembly according to the invention, showing the sleeve in an expanded state. FIG. 2 is a cross-sectional view of the assembly shown in FIG. 1, showing the sleeve retracted relative to the cable connection. FIG. 3 is a cross-sectional view of the assembly in place on the cable connection section, with only the central section open and repaired with a heat shrinkable split sleeve. FIG. 4 is a cross-sectional view of the assembly in place on the cable connection, with the heat shrink IJ-
Indicates the state in which it has been repaired. FIG. 5 shows an aluminum comb used in the assembly of the present invention. FIG. 6 is a cross-sectional view of an assembly of the invention having two combs;
The sleeve is shown in an expanded state. FIG. 7 is a cross-sectional view of the assembly of FIG. 6 positioned over the electrical cable connection, with the sleeve retracted. Figure 8 shows a bayonet type fitting. In the figure, 1 is a heat shrink sleeve, 2 is a tube, 3°3a is a semi-cylinder, 4 is a support ring,
5 is a sealant, 6.6' is one end section, 7 is a connecting part, 8
1 is an electrical cable, 9, 9' is a central section, 10 is a split sleeve, 11 is a sealant, 12 is a flexible rail, 13 is a split sleeve, 14 is a flexible rail, 15 is a comb, 16 is a protrusion, 1
7 is a band, 18 is an end, and 19 is an end section.

Claims (1)

[Scope of Claims] 1. An assembly for protecting and insulating a connecting portion between electric wires, comprising: a relatively rigid split pipe having a diameter and an axial split that match the connecting portion; a split tube supported at each end by a support means, and a heat shrink surrounding the split tube extending over the entire length of the split tube and the support means and capable of contacting the electrical wire at each end. a sleeve, at least the end of the sleeve has a sealing material on its inner wall, and the diameter of the contracted sleeve is continuous between the diameters of the split wire when the assembly is assembled. Assemblies that change over time. 2. In an assembly for protecting and insulating connections between electric wires, a relatively rigid split tube having a diameter and an axial split compatible with the connection, each end being supported by a relatively rigid support means. a plurality of relatively flexible protrusions spaced around at least one end of the stack and projecting axially beyond the end; The stacking tube and the projection are surrounded by a heat-shrinkable sleeve that is longer than the length of the tube with the projection, a sealing material is applied to at least the end region of the inner wall of the heat-shrinkable sleeve, and the sleeve is shrunk over the connecting part. An assembly in which an end region of the sleeve contracted over the wire seals the wire when the sleeve is contracted, and the diameter of the contracted sleeve varies continuously between the diameter of the split tube and the wire. 3. The assembly of item 2 above, wherein the protrusion is integral with the support means. 4. The assembly of item 2 above, in which the protrusion is not integral with the support means. 5. An assembly according to any of the preceding clauses 2 to 4, wherein the sealing material is provided over the entire inner wall of the sleeve. 6. The assembly of any of clauses 2 to 4 above, wherein the sleeve has no sealing material on the inner surface portion overlying the split tube. 7. An assembly according to any of clauses 2 to 6 above, wherein the sleeve is axially split and includes means for sealing the split portions. 8. An assembly according to any of clauses 2 to 7, wherein the support means comprises a ring located at least partially within each end of the split tube. 9. An assembly according to any of clauses 2 to 8, wherein the split tube is of a material that does not bond with the sealing material on the sleeve, at least on its outer surface. 10. The assembly according to any one of items 2 to 9 above, wherein the split pipes are comprised of a pair of semi-cylinders connected by a hinge device. 11. The assembly according to item 2 above, wherein the protrusion is tapered toward the tip. 12. A method of coating a connection between electrical wires, comprising the steps of: positioning a support means at each end of the connection; positioning a heat shrink sleeve having a length sufficient to extend over the entire length thereof over the split pipe and the support means; and positioning the sleeve over the split pipe and the support means. and shrinking the sleeve into close contact with the wire, wherein the diameter of the shrunken sleeve changes continuously between the diameters of the split tube and the wire.