STRIP FOR WINDING AROUND AND GRIPPING AN ELONGATE OBJECT

Abstract: A strip (1) for winding around and gripping an elongate object, e.g. a cable (37), each end of the strip (1) comprising a connection part (9a) which may interlock with a respective connection part (9b) of another, substantially identical, strip (1), thereby enabling a plurality of such strips (1) to be connected together substantially end-to-end to form a longer strip for winding around and gripping an elongate object.

Description: Strip for winding around and gripping an elongate object The present invention relates to a strip for winding around and gripping an elongate object, and to a kit of parts for forming such a strip. The elongate object may, for example, be one or more cables (especially telecommunications cables), wires, optical fibres or the like, or it may be one or more tubes or pipes or the like. In the art of cable splice closures, it is known to wrap tape around a cable in order to build up its diameter to that ofa cable entry port of a splice closure, in order to seal the closure. For example, US Patent No. 4933512 discloses a cable junction closure comprising a sleeve, a pair of rigid end plates for closing the spaces between the cables and the sleeve, an elastic tape wound around the cables for sealing any gaps between the cables and the rigid end plates, and an elastic tape wound around each rigid end plate for sealing any gaps between the end plates and the sleeve. US Patent No. 5124507 comprises a sleeve, sealing members with cable passage openings for insertion in the ends of the sleeve, and semi-circular sealing elements in the form of individually removable bearing shells lining the cable passage openings of the sealing members, for adapting the openings to different cable diameters. In order to eliminate any air gaps between the cable and the surrounding bearing shells, a sealing tape or band is wound onto each cable. US Patent No. 5346742 discloses a sealing tape for winding around a cable leading through a cable passage opening, to form a seal which fits between the cable and the cable passage opening. The inside of the tape facing the cable has a roughened surface to increase the friction between the tape and the cable. The roughened surface is formed by projecting friction elements, which may be made from ine-grained carborundum or emery embedded in an adhesive layer, or from metal or plastic teeth anchored in the material of the tape. Co-pending International Patent Application No. PCT/GB95/02229 (Raychem) discloses a retention strip for winding around an elongate object, which when so wound in use can decrease in length when compressed around the object, thereby allowing contraction of the strip around the object. The entire disclosure of PCT/GB95/02229 is incoφorated herein by reference. The present inventors have now invented a new strip (which may be called a "retention strip") which can be wound around a cable or other elongate object to retain the elongate object in place with respect to another article (e.g. a cable splice closure), and preferably also to retain sealing material in place around the elongate object on one side of the strip. The strip is particularly useful in applications in which an elongate object (e.g. an electrical or telecommunications cable, or a pipe) extends through an aperture in an article, and the elongate object needs to be secured to the article and/or any gaps between the article and the elongate object need to be closed. More especially, the strip has utility as part ofa cable splice closure. For example, the strip may be wound around a cable (or more than one cable) in order to increase the effective diameter of the cable so that it is substantially the same as, or at least closer to, the diameter of a cable entry aperture of a cable splice closure. Depending upon the diameter of the aperture and the diameter of the cable or other elongate object, the length of strip required will vary. According to a first aspect, the present invention provides a strip for winding around and gripping an elongate object, each end of the strip comprising a connection part which may interlock with a respective connection part of another, substantially identical, strip, thereby enabling a plurality of such strips to be connected together substantially end-to-end to form a longer strip for winding around and gripping an elongate object. According to a second aspect, the invention provides a strip for winding around and gripping an elongate object, comprising a plurality of component strips according to the first aspect of the invention connected together substantially end-to- end. According to a third aspect, the invention provides a kit of parts, comprising a plurality of substantially identical component strips for winding around and gripping an elongate object, each end of each component strip comprising a connection part which may interlock with a respective connection part of the other, or another, said substantially identical component strip, thereby enabling said plurality of component strips to be connected together substantially end-to-end to form a longer strip for winding around and gripping an elongate object. , When it is stated herein that the component strips are connected together substantially end-to-end, this includes the possibility of some overlap between the interconnected strips. In fact, in preferred embodiments of the invention, there is overlap, at least between the connection parts of the interconnected strips. The invention has the advantage that because a plurality of the strips may be connected together substantially end-to-end by means of the interlocking connection parts at the ends of the strips, the necessity of manufacturing continuous lengths of strip at the maximum length required for each application is avoided. Instead, the required length of strip may be assembled by connecting together the appropriate number of individual strips. This is particularly advantageous, for example, when the strip is moulded (e.g. from a plastics material), since moulding continuous lengths of strip at the maximum required length would normally be inefficient and expensive, since normally a range of lengths of strip is required, and the excess strip lengths would generally go to waste. Also, strip length requirements vary, and it cannot be guaranteed that the maximum strip length currently required will not, in the future, increase. For example, at present, the maximum length of strip normally required is "in the region of 50-60 cm, but the average length of strip normally required is in the region of 20 cm. It cannot be guaranteed that in the future the normal maximum length required will not increase to. say, 70-80 cm. Furthermore, a range of lengths of strip between about 20 cm and about 60 cm is needed, and simply cutting a 60 cm length of strip into shorter lengths will normally result in a significant amount of waste. The individual strips which are connected together (the "component strips " ') may be supplied un-connected as a kit. At the time of installation, the appropriate number of component strips may be selected from the kit and connected together in order to assemble a longer strip of the required length. Alternatively, strips of the correct length for each particular application may be supplied pre-assembled from the appropriate number of component strips. Component strips may be added to, or removed from, the pre-assembled strip, if required. In preferred embodiment of the invention, each connection part of each component strip is substantially incapable of interlocking with one of the connection parts of another substantially identical strip. The two connection parts of the, or each, strip preferably each have a different shape. Preferably, neither connection part of the, or each, strip is capable of interlocking with a substantially identical connection part of another substantially identical strip. It is particularly preferred that at least one of the connection parts (hereinafter called an overlapping connection part) of each component strip is shaped to overlap at least part of the connection part (hereinafter called an overlapped connection part) of another substantially identical strip with which it may interlock. Preferably, the or each overlapping connection part overlaps the overlapped connection part on both of the two main surfaces of the other substantially identical strip when the two connection parts are interlocked. The two connection parts preferably overlap each other, and so the - designations "overlapping" and "overlapped", as used herein, may be arbitrary. Each overlapping connection part preferably extends through at least one opening in the overlapped connection part when the two connection parts are interlocked. Each overlapping connection part preferably includes at least one step which enables it to overlap the overlapped connection part on one of the two main surfaces of the other substantially identical strip, to extend through the opening in the overlapped connection part, and to overlap the overlapped connection part on the other of the two main surfaces of the other substantially identical strip, when the two connection parts are interlocked. Each overlapping connection part may comprise one or more extending parts which extend from a main part of the strip. Advantageously, the or each extending part may include at least one said step. , In particularly preferred embodiments of the invention, a main surface of each strip is adapted to face towards an elongate object when the strip is wound around the elongate object, and the connection parts are preferably shaped such that when each connection part interlocks with is respective connection part of the other substantially identical strip, the interlocking of the connection parts is reinforced when the interconnected strips are so wound around the elongate object. Advantageously, the main surface of each strip which is adapted to face towards the elongate object has a plurality of protrusions thereon, to enhance the grip of the strip on the elongate object. It is most preferred that the overlapping and overlapped connection parts are shaped such that when they are interlocked, and the interconnected strips are wound around an elongate object, an end of the overlapping connection part which is furthest from the main part of the strip of which it is part, is located between the elongate object and the other, substantially identical, strip (i.e. on the "inside" of the other strip). Each connection part of each strip preferably includes one or more projections " and/or recesses which interlock with one or more recesses and/or projections, respectively, of the connection part of another, substantially identical, strip with which it interlocks. The or each component strip is preferably formed (e.g. moulded) at least in part from a plastics material, e.g. polyethylene, polypropylene or polystyrene. According to some aspects of the invention, not all of the component strips need necessarily be substantially identical to each other. For example, there may be two different types of strip. One type of strip may be connectable to the other type of strip, but strips of the same type may be incapable of being connected together, for example. Thus, according to a fourth aspect of the invention, there is provided a kit of parts, .comprising two component strips for winding around and gripping an elongate object, each end of each component strip comprising a connection part which may interlock with a respective connection part of the other component strip, thereby enabling the two strips to be connected together substantially end-to-end to form an interconnected pair of strips, and enabling a plurality of such pairs of component strips to be connected together substantially end-to-end, to form a longer strip for winding around and gripping an elongate object. The component strips which may be interconnected may be substantially identical to each other, or they may be different to each other. A fifth aspect of the invention provides a strip for winding around and gripping an elongate object, comprising two component strips, an end of each component strip comprising a connection part which is interlocked with said connection part of the other component strip such that the two strips are connected together substantially end-to-end to form an interconnected pair of component strips, and each end of the interconnected pair of component strips comprises a connection part which may interlock with a respective connection part of a substantially identical interconnected pair of component strips, thereby enabling a plurality of such interconnected pairs of strips to be connected together substantially end-to-end to form a longer strip for winding around and gripping an elongate object. In preferred embodiments of each aspect of the invention. when each component strip is connected to another component strip, and the interconnected strips are wound around an elongate object, the interconnected strips can decrease in length when compressed around the elongate object, thereby allowing contraction of the interconnected strips around the elongate object. This contraction of the wound strip around the elongate object may have one or both of two important advantages, as follows. Firstly, it may enable a compression force to be transmitted effectively to a cable or other elongate object around most, or preferably all, of the circumference of the cable, thereby causing the cable to be gripped firmly and therefore, for example, secured to a cable splice closure against external forces acting on the cable. Secondly, the fact that preferred strips according to the invention may contract around a cable may mean that they can provide enhanced sealing around the cable, for example to seal a cable splice closure from the environment. The contraction itself, may, in some circumstances, result in better sealing compared to that provided by known strips or tapes which do not contract in the manner of the invention. Even more advantageously however, use of such preferred strips normally provides better sealing than would be possible with known strips or tapes, when compressed around the cable. This may be because, for example, known strips or tapes may buckle under compression due to their inability to contract, thereby forming gaps between the buckled parts. The strip of the invention preferably contracts by the correct amount at each part of the circumference of the cable, thereby substantially preventing the formation of gaps which would normally form if a known (non-contracting) type of strip were used. The strip may, for example, of itself form a satisfactory environmental seal for a cable splice closure. Additionally or alternatively, the strip -may, for example, provide sufficient retention of sealing material in a cable splice closure to enable the closure to be sealed from the environment by the sealing material. Preferably, therefore, when the strip according to the invention is contracted around an elongate object, it can substantially prevent passage of sealing material therethrough along the object, thereby retaining the sealing material on one side thereof. Known tapes and strips do not have the above advantage because they do not decrease in length when compressed around a cable or the like, and hence they cannot normally contract around the cable in the manner of preferred strips according to the invention. The preferred strips of the invention have the advantage that they can be radially contracted when wound around an object, the requisite circumferential contraction being accommodated, at least in part, by a reduction in the length of the strip. Preferably, each component strip comprises one or more, preferably a plurality, of collapsible portions, and each component strip and the component strips when interconnected, can decrease in length due to the collapsing of one or more of the collapsible portions. The collapsible portion(s) may collapse by means of any of a variety of mechanisms, for example by telescoping (in a manner similar to a collapsible telescope). Preferably, however, the or each collapsible portion can collapse by deforming, e.g. by being crushed or by buckling. Preferably such deformation occurs in a direction generally or substantially parallel to the (axial) direction of extension of the elongate object around which the strip is wound, in use, and can be directed inwardly and/or outwardly, preferably outwardly, with respect to the remainder of the strip. This generally has the advantage of not giving rise to the formation of gaps (or at least significant gaps) between the windings of the strip through which sealing material might otherwise be able to escape. The or each collapsible portion preferably comprises a relatively weak portion of the retention strip. More preferably, the or each collapsible portion comprises one or more webs extending between substantially non-collapsible portions, e.g. one or more relatively "thin portions which can deform, e.g. by buckling. Preferably, each component strip comprises a plurality of alternately collapsible and non-collapsible portions along at least pan, preferably all, of the length thereof. This has the advantage of normally providing substantially uniform collapsibility along the length of the strip, such that the strip may contract relatively or substantially uniformly around an elongate object. The or each collapsible portion (where present) of the strip may advantageously provide the flexibility to enable the strip to be wound around an elongate object. The or each substantially non-collapsible portion may, for example, be relatively or substantially inflexible: this stiffness can have the advantage of enabling the substantially non-collapsible portions of the strip to grip an elongate object relatively firmly. Advantageously, therefore, the strip may comprise a plurality of alternately substantially inflexible and flexible portions along at least part of its length. According to particularly preferred embodiments of the invention, each component strip is profiled such that, when spirally wound around an elongate object in use, successive windings interlock with each other, thereby substantially preventing helical displacement of the windings with respect to each other along the object. This may provide at least two important advantages. Firstly, it generally provides the strip with strength to resist axial forces acting on an elongate object (e.g. a cable) when it is wound around the object, i.e. it can substantially prevent the strip from telescoping out along the elongate object under the action of such axial forces, and therefore the grip of the strip on the elongate object can normally be retained. Secondly, it generally prevents accidental displacement of the windings of the strip with respect to each other (e.g. due to axial forces of the elongate object or for some other reason), which might otherwise compromise the ability of the strip to retain sealing material. The strip may, for example, have a plurality of protrusions and recesses which can engage -with each other when the strip is wound in use. More preferably, the or each substantially non-collapsible portion (where present) of the strip has one or more projections on one surface thereof and one or more cooperating recesses on the opposite surface thereof, such that, for example, when the strip is wound around an object the projection(s) of one non-collapsible portion fit together with the recess(es) of another non-collapsible portion which it overlaps, or by which it is overlapped. A fifth aspect of the invention provides a cable splice closure, comprising a housing to enclose a cable splice, the housing having one or more cable entry apertures therein, and a kit or one or more strips according to any of the other aspects of the invention, to grip one or more cables extending, in use, into the housing through a said cable entry aperture. The invention will now be described, by way of example, with reference to the accornpanying drawings, of which: Figure 1 shows one end region of a component strip according to the invention; Figure 2 shows the other end region of the strip shown in Figure 1 ; Figure 3 shows two strips identical to the strip shown in Figures 1 and 2, connected together; and Figure 4 shows, schematically, part ofa cable splice closure incoφorating strips according to the invention. Figures la and lb show opposite main surfaces of one end region ofa component strip 1 according to the invention. Figure la shows the main surface 3 of the strip 1 , which, in use, faces towards a cable or other elongate object, and which has a plurality of protrusions 5 for enhancing the grip of the strip on the cable. Figure ~ lb shows the opposite main surface 7 of the strip 1 which, in uses, faces away from the cable. The end of the strip comprises a connection part 9a (referred to herein as an "overlapping" connection part) which comprises two extending parts 11 extending from a main part 13 of the strip. The connection part 9, and the rest of the strip 1, will be described in more detail below. Figures 2a and 2b show the opposite main surfaces 3 and 7, respectively, of the component strip 1. at the opposite end region of the strip. This opposite end of the strip comprises a connection part 9b (refeπed to herein as an 'Overlapped" connection part) which, in use, interlocks with the type of connection part 9a shown in Figure 1 , of another (substantially identical) component strip 1. Figures 3 a and 3 b show the opposite main surfaces 7 and 3, respectively, of the component strip which component strip is connected to another, substantially identical, component strip, in the region where the connection parts 9a and 9b of the strips interlock with each other. It can be seen that the extending parts 11 of the connection part 9a each extend through an opening 15 in the connection part 9b. The extending parts 11 each have a step 17 which enables the extending parts of the "overlapping" connection part 9a to overlap the "overlapped" connection part 9b on one main surface 7 of the other strip, to extend through the opening 15 in the "overlapped" connection part 9b, and to overlap the "overlapped" connection part 9b on the other main surface 3 of the other strip. (The terms "overlapped" and "overlapping" are arbitrary, and are used simply for convenience to distinguish between the two types of connection part). Thus, main surface 3 of connection part 9a is in contact with main surface 7 of connection part 9b, and main surface 7 of connection part 9a is in contact with main surface 3 of connection part 9b. In this way, the connection parts 9a and 9b are mutually interlocked. Also, the extending parts 11 of the "overlapping" connection part 9a have projections 19 thereon, which interlock with corresponding recesses (e.g. holes) 21 in the "overlapped" connection part 9b, to help retain the two strips connected together. It can also be seen from Figure 3 that when, in use, the interconnected strips are wound around an elongate object, an end 23 of the "overlapping" connection part 9a which is furthest from the main part 13 of the strip of which it is part, will be located between the elongate object and the other strip. This is because this end 23 of the "overlapping" connection part 9a is in contact with (i.e. on top of) the main surface 3 of the other strip, which is adapted to face towards the elongate object. Because of this, the interlocking of the connection parts will be reinforced when the interconnected strips are wound around an elongate object. The strips 1 shown in Figures 1 to 3 also include a plurality of alternate collapsible portions 25 and non-collapsible portions 27 along the lengths thereof. The collapsible portions 25 each comprise two webs extending between two non- collapsible portions 27 at the edges of the strip 1. The webs 25 can deform, e.g. by buckling, when, in use the wound strip is radially compressed around a cable or other elongate object. The strips 1 also have protrusions 29 and recesses 31 which can engage corresponding recesses 31 and protrusions 29 of adjacent windings of the interconnected strips when, in use, the strips are wound around a cable etc. As mentioned above, this profiling of the strips has the advantage of substantially preventing accidental axial displacement of the windings of the interconnected strips with respect to each other. Also, the protrusions 29 and recesses 31 may engage corresponding parts of a housing of a cable splice closure, to secure the wound strips to the closure. Figure 4 shows, schematically, part ofa cable splice closure 33 according to the invention, incoφorating strips 1 according to the invention. The closure 33 comprises a housing 35 having cable entry apertures containing interconnected component strips 1 wound around cables 37 which are extending into the housing through the apertures. The interconnected component strips 1 have each filled the annular gap between their respective cable 37 and entry aperture. One cable 37 is -smaller in diameter than the other, and because the cable entry apertures are the same size as each other, the strip wound around this cable is longer than that wound around the other cable. To achieve this, a greater number of individual component strips are connected together than in the other strip.

Claims: Claims 1. A strip for winding around and gripping an elongate object, each end of the strip comprising a connection part which may interlock with a respective connection part of another, substantially identical, strip, thereby enabling a plurality of such strips to be connected together substantially end-to-end to form a longer strip for winding around and gripping an elongate object. 2. A kit of parts, comprising a plurality of substantially identical component strips for winding around and gripping an elongate object, each end of each component strip comprising a connection part which may interlock with a respective connςction part of the other, or another, said substantially identical component strip, thereby enabling said plurality of component strips to be connected together substantially end-to-end to form a longer strip for winding around and gripping an elongate object. 3. A strip according to claim 1 , or a kit according to claim 2, in which each connection part of the, or each, strip is substantially incapable of interlocking with one of the connection parts of said other, substantially identical, strip. 4. A strip or kit according to any preceding claim, in which the two connection parts of the, or each, strip each have a different shape. 5. A strip or kit according to claim 4, in which neither connection part of the, or each, strip is capable of interlocking with a substantially identical connection part of said other, substantially identical, strip. 6. A strip or kit according to any preceding claim, in which at least one of the -connection parts (hereinafter called an overlapping connection part) of the or each strip is shaped to overlap at least part of the connection part (hereinafter called an overlapped connection part) of said other, substantially identical, strip with which it may interlock. 7. A strip or kit according to claim 6, in which the or each said overlapping connection part overlaps the overlapped connection part on both of two main surfaces of said other, substantially identical, strip when the two connection parts are interlocked. 8. A strip or kit according to claim 7, in which the or each said overlapping connection part extends through at least one opening in the overlapped connection part when the two connection parts are interlocked. 9. A strip or kit according to claim 8, in which the or each said overlapping connection part includes at least one step which enables it to overlap the overlapped connection part on one of said two main surfaces of said other, substantially identical, strip, to extend through said opening in the overlapped connection part, and to overlap the overlapped connection part on the other of said two main surfaces of said other, substantially identical, strip, when the two connection parts are interlocked. 10. A strip or kit according to any one of claims 6 to 9, in which the or each said overlapping connection part comprises one or more extending parts which extend from a main part of the strip. 11. A strip or kit according to claim 10 when dependent upon claim 9, in which the or each extending part includes at least one said step. 12. A strip or kit according to any preceding claim, in which a main surface of the. or each, strip is adapted to face towards an elongate object when the strip is wound - around said elongate object, and the connection parts are shaped such that when each connection part interlocks with its respective connection part of said other. substantially identical, strip, the interlocking of the connection parts is reinforced when the interconnected strips are so wound around said elongate object. 13. A strip or kit according to claim 12, in which said main surface of the, or each, strip which is adapted to face towards an elongate object has a plurality of protrusions thereon, to enhance the grip of the strip on the elongate object. 14. A strip or kit according to claim 12 or claim 13, when dependent upon any one of claims 6 to 1 1 , in which the or each said overlapping and overlapped connection parts are shaped such that when they are interlocked, and the interconnected strips are wound around an elongate object, an end of the overlapping connection part which is furthest from the main part of the strip of which it is part, is located between the elongate object and said other, substantially identical, strip. 15. A strip or kit according to any preceding claim, in which each connection part of the, or each, strip includes one or more projections and/or recesses which interlock with one or more recesses and/or projections, respectively, of the connection part of said other, substantially identical, strip with which it may interlock. 16. A strip for winding around and gripping an elongate object, comprising a plurality of strips according to any one of claims 1 or 3 to 15 connected together substantially end-to-end. 17. A kit of parts, comprising two component strips for winding around and gripping an elongate object, each end of each component strip comprising a connection part which may interlock with a respective connection part of the other component strip, thereby enabling the two strips to be connected together substantially end-to-end to form an interconnected pair of component strips, and enabling a -plurality of such pairs of strips to be connected together substantially end-to-end, to form a longer strip for winding around and gripping an elongate object. 18. A strip for winding around and gripping an elongate object, comprising two component strips, an end of each component strip comprising a connection part which is interlocked with said connection part of the other component strip such that the two strips are connected together substantially end-to-end to form an interconnected pair of component strips, and each end of the interconnected pair of strips comprises a connection part which may interlock with a respective connection part ofa substantially identical interconnected pair of component strips, thereby enabling a plurality of such interconnected pairs of component strips to be connected together substantially end-to-end to form a longer strip for winding around and gripping an elongate object. 19. , A strip or kit according to any preceding claim, in which when the, or each, strip is connected to said other strip, and the interconnected strips are wound around an elongate object, the interconnected strips can decrease in length when compressed around the elongate object, thereby allowing contraction of the interconnected strips around the elongate object. 20. A strip or kit according to claim 19, in which the, or each, strip comprises one or more, preferably a plurality of, collapsible portions, and the interconnected strips can decrease in length due to the collapsing of one or more of the collapsible portions. 21. A strip or kit according to claim 20, in which the or each collapsible portion comprises one or more webs extending between substantially non-collapsible portions. 22. A strip or kit according to claim 20 or claim 21 , in which the, or each, strip comprises a plurality of alternately collapsible and substantially non-collapsible portions along at least part of the length thereof. 23. A strip or kit according to any one of claims 20 to 22, in which the or each ' collapsible portion provides the flexibility to enable the strip to be wound around an elongate object. 24. A strip or kit according to any preceding claim, in which the. or each, strip is profiled such that, when wound around an elongate object, successive windings interlock with each other, thereby substantially preventing displacement of the windings with respect to each other along the object. 25. A cable splice closure, comprising a housing to enclose a cable splice, the housing having one or more cable entry apertures therein, and a kit of parts or one or more strips according to any preceding claim, to grip one or more cables extending, in use, into the housing through a said cable entry aperture.

Inventors: DAMS FRANCIS, MICHIELS MAARTEN, VANDEPOEL JOS, DAMS, FRANCIS, MICHIELS, MAARTEN, VANDEPOEL, JOS
Applicants: DAMS FRANCIS, MICHIELS MAARTEN, RAYCHEM LTD, RAYCHEM SA NV, VANDEPOEL JOS, DAMS, FRANCIS, MICHIELS, MAARTEN, N.V. RAYCHEM S.A., RAYCHEM LIMITED, VANDEPOEL, JOS
Application year: 1997
Main classification: H02G15
IPC codes: H02G15