JPH0376094B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a liner with tapered protrusions,
More specifically, the present invention relates to a liner used in an assembly for insulating and protecting a connecting portion of a conduit such as a multicore cable.

[Prior Art] It is often necessary to insulate and protect connecting portions between conduits, typically electrical cables such as multicore 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, GB 1155470 proposes the use of sleeves or tubes made of heat-shrinkable material, which may have longitudinal cuts, to protect and insulate the connections of electrical cables. The sleeve has a suitable initial diameter under stress so that it can be easily moved into position, and when heated it contracts to fit tightly over the connection. It is becoming possible to do so.

Since cables often need to be pressure and water resistant, it is necessary to coat the inner wall of the heat-shrinkable sleeve with a sealing compound, such as mastic 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. The disadvantage of this type of protective sleeve for enclosing the connection part is that in some cases it cannot be opened easily when attempting to carry out repairs or modifications, for example when attempting to insert additional cables. The entire connection must be renewed.

British Patent No. 1248908 discloses a method for connecting electrical cables, in which a bridge sleeve made of non-heat-shrinkable material and an end sleeve made of heat-shrinkable material are used, said sleeves being interconnected, for example by screws. is connected to. Such an assembly unit is positioned such that the bridge sleeves are positioned 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 for easy engagement of the male and female threads on the bridge sleeve and the end sleeve.

One way to solve these problems in the prior art is to create a relatively rigid split pipe with an inner diameter and axial split that match the connecting portion, and to support the split pipe at each end. Rigid support means,
a plurality of relatively flexible protrusions spaced around at least one end of the split tube and projecting axially beyond the end; surrounded by a cylindrical heat-shrinkable sleeve having a length greater than the combined length of the protrusion, such that the end region of the sleeve that shrinks onto the conduit when the heat-shrinkable sleeve is shrunk onto the connection portion is sealed to the conduit; An assembly is proposed in which a sealing material is applied to at least a portion of the inner wall of the sleeve, and the protrusion causes the diameter of the contracted sleeve to vary continuously between the split tube and the conduit.

[Problems to be Solved by the Invention] However, in the assembly as described above, if the protrusion is formed into a rectangular shape, when the tip of the protrusion is pressed against, for example, a multicore cable by the contraction force of the heat-shrinkable sleeve, the protrusion Sharp corners and edges can damage the cable sheath and destroy the insulation.
Also, the protrusions overlap each other, making the sleeve surface irregular or damaged.

[Means for Solving the Problems] The present invention has been made to improve such drawbacks, and provides a liner for supporting an enclosure having a heat-shrinkable sleeve surrounding the connection between conduits. the liner having a plurality of relatively flexible projections spaced apart from one end thereof, projecting from the end and tapering distally, the projections forming a connection between the conduits; To provide a liner which gives a smooth change in the diameter of a heat-shrinkable sleeve between different diameters when the sleeve is shrunk.

An example of the liner of the present invention is shown in FIG. The liner is formed from a comb 15 consisting of a plurality of flat projections 16 extending from a monolithic strip 17. The tip 18 of the protrusion 16 is tapered.

Other elements of the above assembly constituting the enclosure using the liner of the present invention will be explained.

First, the support means for the split tube is preferably 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 heat shrinkable sleeve that shrinks over the split tube does not or only minimally seals the split tube. 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-shrinkable sleeve are covered with a sealing compound, such as mastic or hot melt adhesive, leaving a central section of length substantially equal to the length of the split tube uncoated to prevent shrinkage. When generated, only the covered end of the sleeve is allowed to shrink onto and bond to the conduit, while the uncoated central section is allowed to shrink without bonding over the split tube.

The heat-shrinkable 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 the contraction has taken place.

Split pipes of relatively rigid material are typically formed by a pair of half-cylinders, which may be connected (or unconnected) by a hinge arrangement. Note that the tube can also be formed with a single split or with two members of different sizes.

The connection sheathing assembly is easily opened by cutting the center portion of the heat shrinkable sleeve to allow repair or modification of the connection. 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 desired 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-shrinkable 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 as described in GB 1155470 is particularly suitable.

The material of the split pipe has at least its outer surface,
Preferably, the material does not combine with the selected sealant on the surrounding sleeve, allowing the connection to be reopened during subsequent repairs or alterations.

When connecting cables, it may be necessary to add a new cable to the connection. 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. Next, remove the split pipe and the support means,
Insert the new cable and wrap sealing tape all over. After refitting the split tube and the liner of the invention, the new connection is fitted with a notched, surrounding heat-shrinkable sleeve, such as British Patent No. 1155470.
covered by a closure of the type described in No.

The heat-shrinkable sleeve is preferably formed to have a length greater than the combined length of the split tube, support means and liner protrusion.

When heat is applied to the heat-shrinkable sleeve, 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 progressively susceptible to contraction from the end of the tube towards the end of the projection. This is because the protrusion becomes progressively more deformable towards its end, and near the end the sleeve contracts tightly against the wire. By providing such protrusions, the sleeve can smoothly taper in diameter from the large diameter section surrounding the split tube to the small diameter section surrounding the wire, thereby reducing the sleeve material. The stress on the tube 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-shrinkable 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 coated. do. The central section, which is slightly longer than the split pipe and the support means, is therefore uncoated and, if shrinking is carried out, the coated ends of the sleeve are exposed to the projections, wires and if support rings are used. The support ring is then contracted and the uncoated central section is contracted onto the split tube.

The liner with the protrusions can be formed integrally with the support means for the split tube, or can be a separate assembly fixed to the support device, for example by soldering. However, it is desirable that the liner not be attached directly to the split pipe itself. The reason for this is that if installed in this manner, the split pipe will not be able to open during repairs or the like. The projections form a profile or comb in which they are formed integrally with a portion of the band. 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 liner of the present invention can be suitably made of aluminum, which has high strength, light weight, and flexibility, but may also be made of cardboard or the like. The protrusions of the liner of the present invention should be tapered towards their ends, with progressively increasing deformability towards their free ends, yet the protrusions should not overlap upon contraction of the heat-shrinkable sleeve. be.

The tubes with longitudinal splits and the supporting elements can be made of suitable materials, such as metal, hard rubber or synthetic materials, such as polyethylene, especially high-density polyethylene, which may contain customary additives (fillers). , pigments, flame retardants, antioxidants, etc.). If the connection part is to be formed inside the power cable, the material should be irradiated as much as possible.
It should not melt even when overload occurs. Other suitable plastic materials include polyvinyl chloride and polypropylene.

The split tubes can be made of an electrically insulating material, a semiconductive material, or an electrically conductive material, as required.

The heat-shrinkable sleeve may be made of any suitable material, such as those described in British Patent Nos. 990,235 and 1,062,043. The tube is preferably formed from a polyolefin, preferably a polyethylene crosslinked by chemical means or by radiation and containing the usual additives (fillers, flame retardants, antioxidants, etc.).

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 if the assembly comprises a protrusion and the optimal position of said protrusion is to be maintained when contraction is performed.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an example of a liner with tapered protrusions of the present invention. As shown in this figure, the liner is formed as a comb-like member 15 consisting of a plurality of flat parallel projections 16 extending from a monolithic strip 17. The projection 16 is tapered toward its tip 18.

An example of an assembly using the liner of the present invention is shown in FIG. The assembly consists of a heat-shrinkable sleeve 1 and a relatively rigid longitudinally split tube 2 formed by two half-cylinders 3, 3a and located at each end thereof. It is supported by a relatively rigid support ring 4. The support ring may be, for example, a plug-in type fitting (see Figure 4).
It can be attached to the split pipe 2 by. The comb-like member 15 is fixed to the ring 4 by soldering the band 17 to the outer surface of the ring 4. The heat-shrinkable sleeve 1 surrounding the assembly is formed to be larger than the total length of the split tube 2, ring 4 and protrusion 16. The end section 6 of the inner surface of the sleeve 1 is covered by a sealing material 5 up to approximately the midpoint of the length of the projection 16.

FIG. 3 shows the position in which the connecting portion 7 between the wires 8 is surrounded by the assembly shown in FIG. 2 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 drawings]

FIG. 1 is a developed view of the liner of the present invention.
FIG. 2 is a cross-sectional view of an assembly using the liner of the present invention, showing the sleeve in an expanded state. Third
The Figure shows a cross-sectional view of the assembly of Figure 2 positioned over the electrical cable connection, with the sleeve retracted. Figure 4 shows a bayonet type fitting. 1...Heat-shrinkable sleeve, 2...Split pipe, 3,
3a...Semi-cylinder, 4...Support ring, 5...Sealant, 7...Connection part, 8...Electric cable, 15
... Comb-shaped member, 16 ... Protrusion, 17 ... Band, 18
... Tip section, 19 ... End section.

Claims (1)

Claims: 1. A liner for supporting an enclosure having a heat-shrinkable sleeve surrounding a connection between conduits, the liner having a heat-shrinkable sleeve spaced apart from and projecting from one end of the liner; It has a plurality of relatively flexible protrusions that taper toward the distal end, which protrusions provide a smooth conformation between different diameters of the heat-shrinkable sleeve when the sleeve is shrunk over the connection between the conduits. A liner that makes a difference. 2. The liner according to claim 1, wherein the conduit is a multicore cable and the liner smoothly changes the diameter of the sleeve between the large diameter of the connection and the small diameter of the cable.