GB2061025A - Material for wrapping around pipe, cable or the like - Google Patents

Abstract

A material 10 for wrapping around a pipe, cable or the like in which a flexible sheet 26 of heat shrinkable material such as cross-linked polyolefin is provided on each edge with a clip element eg. of copper or steel, the two elements 13 being formed with body portions 15, 15B attached to the sheet material and hook members 20, 20B which are interengageable. A strip of material on one of the clip elements 21A, or on the flexible material, extends under the free edge of one of the hook members to maintain the other hook member in engagement. <IMAGE>

Description

SPECIFICATION Material for wrapping around a pipe, cable or the like The present invention relates to material for wrapping around a pipe, cable or the like, for example to seal, against the elements, the joint therein.

British Patent No. 1,155,470 suggests a heat recoverable closure member which includes heat shrinkable material having ridges or protuberances adjacent two opposite edges. The material is arranged with the adjacent edges in abutting relationship, and a fastening clip is slid over the ridges to maintain the edges in this abutting relationship.

Heat is then applied and the heat shrinkable material shrinks so that it clamps tightly around the cable, pipe or the like. Material of this type has the advantage that it can be wrapped around existing cables or pipes and does not have to be fed in from one end. This is of great practical importance when one is wishing to seal a joint between conductors in a cable, for example a telephone cable.

The arrangement, however, has the disadvantage that it is necessary to apply the fastening clip from one end of the ridge and this can be difficult in certain circumstances and when so applied can give rise to damage to the sheathing or coating of adjacent cables and/or pipes.

It is now proposed, according to the present invention, to provide material for wrapping around a pipe, cable or the like, comprising a flexible sheet of material which is heat shrinkable in the direction between first and second opposite edges, a first clip element on said first edge and a second clip element on said second edge, the first and second clip elements being interengageable to hold said first and second edges in proximity, means being provided to maintain said clip elements interengagement.

In use, the material is wrapped around the pipe or cable or other material to be covered, and the first and second clip elements are interengaged. Since the means are provided to maintain the clip elements in interengagement, there is no need to carry out any other action prior to heating the thus formed sleeve which can then immediately shrink. Thus there is less likelihood of damaging other cables and the whole operation can be carried out rather more quickly than in the previously suggested device of British Patent 1,155,470.Furthermore, since there is no need to have the extra fastening member of that Patent, which fastening member is usually made of metal, the heating itself can be carried out more readily, because it has been found that the fastening member forms a heat sink tending to reduce the heat which can be applied to the material particularly in the vicinity of the joint formed between the two edges.

Preferably each clip element comprises a body portion secured to the flexible sheet and a hook member extending from said body portion away from the associated edge, the hook members of the two clip elements being bent in opposite senses and being inclined towards the associated body portion.

This inclination facilitates the interengagement of the first and second elements and reduces the possibility of the hook members becoming disengaged once they have been interengaged.

The means which maintain the clip elements in interengagement advantageously comprise a strip extending in front of the free edge of the hook member of one of the clip elements, the hook member of the other clip element being positionable betwen the strip and the hook member of said one clip, whereby the strip prevents disengagement of the two hook members. This strip may form part of one of the clip elements, or may be formed integrally with the flexible strip.

In other embodiments the means which maintain the clip elements in interengagement may arise from the construction of the clip elements themselves; for example, the clip elements might be so shaped that once brought into engagement they will stay engaged until the sheet is heat shrunk and the tension in the sheet maintains the clips in engagement.

In a preferred embodiment of the present invention, each clip element is in the form of an elongate strip which extends along substantially the full length of its associated edge. In order that the material, when shrunk, can conform closely to the shape of the cable or pipe or the like therewithin, particularly if the material enclosed is of irregular cross-section, it is preferable that the strip should be segmented by lines of weakness extending transverse to the associated edge. This can, for example, be achieved by including slots in the body portions and cuts in the hook members, the slots and cuts being aligned with one another.

The body portion can be secured to the flexible material in a number of differentways. For example it can be secured simply by adhesive, by rivets or other similar members, by providing a thickened ridge along the edge of the material engaging in a groove in the body portion or in many other ways which can, advantageously, be effected in the factory. Another method of securing involves providing the body portions with tabs which are bent down from the body portion, passed through the flexible sheet and are bent again to lie substantially flush with the other face of the flexible material. These tabs are advantageously formed in parts of the body portion between each adjacent pair of the slots mentioned above.

The flexible material may be thickened adjacent the first and second edges and the thickening may be of a sufficient amount so that the hooks have a dimension perpendicular to the faces of the sheet material, which is less than the thickness in the thickened portions.

A tongue may be provided to extend from a position adjacent to, but spaced from, one of the opposite edges of the sheet to a location sufficiently beyond the clip element to underlie fully the two clip elements when they are interengaged. This tongue serves to provide a seal at the location of the clip elements.

In order that the invention may more readily be understood, the following description is given, merely by way of example, reference being made to the accompanying drawing in which: Figure 1 is a perspective view of one embodiment of material according to the present invention shown in its assembled condition; and Figure 2 is a perspective view of the two clip elements prior to mounting on the flexible sheet material.

Referring first to Figure 1 there is illustrated a sheet 10 of heat shrinkable material, such as crosslinked polyolefine, having edges 11 and 12. The heat shrinkable material is arranged so that, when heated, it will shrink so that the distance, along the sheet material, between the edges 11 and 12 will reduce.

Two elongate strip material clip elements 13 and 14 are shown secured to the edges 12 and 11 respectively. The strip material 13 has a body portion 15 provided with a series of parallel slots 16 punched out from the body portion. Between adjacent slots 16 are formed apertures 17 again punched from the body portion 15, but having a tab 18 folded down from one edge thereof as can be seen more clearly in Figure 2.

The body portion 15 has extending beyond the edge 12 a hook member 19 which is bent downwardly at an angle of less than 90" so that it is inclined back towards the body portion. As can be seen from Figure 2, the hook member 19 is segmented by cuts 20 which are aligned with the slots 16. In Figure 1, edge 12 of the sheet of heat shrinkable material 10 has an integral tongue 25 which passes under the clip element 14. Figure 2 shows the foot like strip 21A formed integrally with the body 15 and which passes under the hook member 24 of the second clip element 14 and serves to ensure that the clip elements are maintained in interengagement until the material 10 is heat shrunk.

The second clip element 14 is of similar construction having similar slots 16B and apertures 17B providing tabs 18B (Figure 2). Strip 14, however, has a hook member 24 which is complementary to hook member 19 in that it extends in the opposite sense, i.e. upwardly, and is again inclined at an angle of less than 90 so that it extends back towards the body portion 15B of the second clip element 14. Again cuts 20B are provided aligned with the slots 16B.

The material is assembled by pushing the tabs 18, 1 8B through the sheet material 10 adjacent the edges 12, 11, and then bending the tabs back so that they lie substantially flush with the opposite face of the sheet material 10. Many other forms of securing are contemplated, as mentioned earlier.

A fly tongue 25 is provided on the sheet material 10 to extend from a location spaced from the edge 12 or from edge 11 to a position beyond the two clip elements when they are interengaged to seal the pipe wrapping. The function of the strip 21 A may instead be performed by a strip on either edge of the sheet material 10 or the tongue 25 may serve both this function and its sealing function. As mentioned above, in some embodiments the means provided to maintain the clip elements in interengagement may arise from the construction of the clip elements themselves; in those circumstances, if a sealing effect is not required, tongue 25 may be omitted.

In use, the sheet material 10 is wrapped around the cable, pipe, joint etc. and the two clip elements are interengaged either simply by pushing them towards one another, with the inclined hooks 19,24, having their outer faces abutting and thereby pushing down the strip 21A or by bending the flexible material slightly inwardly so that the hooks can be slipped into engagement whereafter the sheet material is broughttothe position illustrated in Figure 1.

In either event, once interengaged as shown in Figure 1, the hooks will not disengage because of the presence of the strip 21A. Thereafter, the material as a whole is heated and the heat shrinkable sheet 10 shrinks and tightly clasps around the pipe, cable, joint etc. Hot melt or other adhesive linings may be provided on the inner surface 26 and mastik or other fillers may be introduced.

While the clips can be made of any suitable material, a metal is preferred such as a plated copper alloy or stainless steel.

It has been found that by heating around the strips 13,14,the material ofthesheet 1 O will well up through the apertures 17 (and also the apertures 16) and start to flow outwards over the upper surfaces of the strips 13, 14, so as to form heads above the surfaces with necked down portions extending through the apertures in the strips. It has been found that these projections through the material sustain the majority of the circumferential tension when sheet 10 is heat shrunk. In view of this, if the projections are formed during heat shrinking, whatever other means are used to secure the strips 13 and 14 to the sheet 10 prior to heat-shrinking need not be capable of sustaining the circumferential tension. Thus, for example, the tabs 18, 18b may be omitted. For the purpose of enabling suitable projections to form, the apertures in the strips 13 and 14 are preferably between about 2 and 5 mm across in the direction along the strips.

Claims (13)

1. Material for wrapping around a pipe, cable or the like, comprising a flexible sheet of material which is heat-shrinkable in the direction between first and second opposite edges, a first clip element on said first edge and a second clip element on said second edge, the first and second clip elements being interengageable to hold said first and second edges in proximity, means being provided to maintain said clip elements in interengagement.

2. Material according to claim 1, wherein each clip element comprises a body portion secured to the flexible sheet and a hook member extending from said body portion away from the associated edge, the hook members of the two clip elements being bent in opposite senses and being inclined towards the associated body portion.

3. Material according to claim 2, wherein the means provided to maintain the clip elements in interengagement comprises a strip extending in front of the free edge of the hook member of one of the clip elements, the hook member of the other clip element being positionable between the strip and the hook member of said one clip element, whereby the strip prevents disengagement of the two hook members.

4. Material according to claim 3, wherein the strip forms a part of said one clip element.

5. Material according to Claim 3, wherein said strip is made integral with said flexible sheet.

6. Material according to Claim 2,3,4 or 5, wherein each clip element is in the form of an elongate strip extending along substantially the full length of the associated edge.

7. Material according to Claim 6, wherein the elongate strip is segmented by lines of weakness extending transverse to the associated edge.

8. Material according to Claim 7, wherein the lines of weakness include slots in the body portions and cuts in the hook members, the slots and cuts being aligned.

9. Material according to any one of claims 2 to 8, wherein the body portions are secured to the material by tabs bent down from the body portions, passed through the flexible sheet and bent again to lie substantially flush with the other face of the flexible material.

10. Material according to Claims 8 and 9, wherein the tabs are formed in parts of the body portion between each adjacent pair of slots.

11. Material according to any preceding claim, wherein the material is thickened adjacent the first and second edges.

12. Material according to any preceding claims, wherein said sheet is provided with a tongue extending from a position adjacent to, but spaced from, one of said opposite edges to a location sufficiently beyond the clip element to underlie fully the two clip elements when they are interengaged.

13. Material for wrapping around a pipe, cable or the like, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.