MXPA97009002A - Side entry enclosure for electrical wiring joints - Google Patents

Abstract

Wrapped side entrance enclosure for primary electrical wiring joints, especially for high-speed automotive installation, uses heat-shrinkable fabric with adhesive coating, whose fabric is clamped around the wiring joint by cloth penetration fasteners such as staples, rivets or cable joints. The fabric has a shrinkage ratio of less than 50% or has a superior shrinkage reaction and is wound loosely enough to limit unresolved residual shrinkage (after shrinkage around the joint) to less than 5%.

Description

SIDE ENTRY ENCLOSURE FOR ELECTRICAL WIRING JOINTS This invention relates to a side entry protective enclosure for a primary electrical wiring union. It is known how to protect such wiring connections by contracting on them a piece of shrinkable plastic tubing, which preferably has an internal coating of heat activatable adhesive. However, such tubing must slide over a free end of the wiring which may be inconvenient or impractical. It has been a problem for a long time to produce a commercially acceptable heat-shrinkable side-entry enclosure for primary wiring junctions, the enclosure of which can be applied laterally to a mid section of the wiring without cutting to produce the free ends. The winding of heat-shrinkable plastic sheets around the joint has proved unsatisfactory due to the lack of economically viable fastening means that can withstand the forces of heat shrinkage. Adhesive fasteners tend to unwind during shrinkage and it is not practical to use over those small-scale wiring unions the heavy duty latch mechanisms that are available for large cable junction boxes, as described for example in GB-A- 2134334.

The present invention provides a surprisingly simple side entrance primary wiring enclosure that can be adapted to provide both technically and economically acceptable results, including in mass production cabling industries, for example automotive wiring assembly lines, where the time of installation and the cost should be minimized. The invention therefore provides a lateral entry protective enclosure for a primary electrical wiring union, comprising an article of such heat shrinkable wound around the joint and clamped around the joint and clamped around the joint with fastening means of fabric cut, the fabric article having a circumferential heat shrinkage ratio in the direction surrounding the junction of no more than 50% or being wound sufficiently loose so that its unresolved shrinkage residual ratio after shrinking tightly around the wiring joint is not sufficient to damage the cloth article, preferably being no more than 50%; and the fabric article having a transverse heat shrinkage ratio (in the direction transverse to the surrounding direction) that is less than half (preferably less than one third, more preferably not more than 20%) of the shrinkage ratio by circumferential heat. The contraction relation by heat is the loss of the length on the contraction expressed as a percentage of the fully contracted length, whose relationship is greatly determined by the degree of tension applied to the shrinkable fibers. For the usual scale of the primary wiring enclosures, it is preferred that the fabric article have a circumferential or residual heat shrinkage ratio of less than 40%, preferably not greater than 33%, more preferably not greater than 25%. It is usually preferred that the fabric article have a heat shrinkage ratio of at least 10%, preferably at least 20%. Circumferential heat shrinkage ratios greater than 50% (eg 100% or 200%) can be used if the article is wrapped around the wiring junction loosely enough so that its residual unresolved contraction ratio after shrinkage around of the wiring union is not more than 50%. It has unexpectedly been found that fastening means penetrating the single-use fabric, for example sewing, or preferably one or more of staples or rivets, for example plastic rivets, hold the fabric article around the wiring joint. without tearing during the subsequent heat shrinkage when the fabric article has the specified circumferential contraction ratios. For narrow winding, those ratios are preferably less than 40% or more of the preferred shrinkage (recovery) ratios for large scale fabric composites in accordance with GB-A-2134334 mentioned above, which compounds may further require modification of the edges of fabric to form the elements of enclosure or reinforcement to resist tearing of the elements of enclosure that penetrate the fabric. The plastic cable joints can be inserted through openings formed (eg by puncture) in the fabric article and can be secured by known techniques to form an alternative fastener for the article. Properly fastening means, rivets for example, can be pre-inserted into an edge region of the fabric article ready for proper fastening after the article has been wound around a wiring ion. It will be understood that the relatively lower transverse shrinkage of the cloth article used in the present invention is preferable for controlling the amount of shrinkage of the enclosure along the enclosed cabling while allowing a useful degree of circumferential shrinkage. Accordingly, a maximum transverse contraction ratio of less than 25%, preferably less than 17%, more preferably no more than 10% is contemplated, generally the lowest is the best. With shrinkage ratios of less than 50%, the cloth article can be tightly fastened around the joint, for example to hold the joint or wiring before the cloth article contracts. Such a narrow winding may be desirable in some circumstances, although in the practical insertion of the cloth cutting fastening means it may advantageously be done with a degree of ease or lacking in the winding. This will usually facilitate the clamping operation and reduce any risk of the clamping means accidentally damaging the cable insulation. It is therefore preferred that the part of the fastening means penetrating the cloth article is separated from the nearest part of the joint or wiring by a distance of up to three times the average diameter (preferably not more than twice the diameter) average) of the largest diameter cable (which includes any insulating layer on it) inside the enclosure. The fabric article can be made from heat shrinkable fibers and other fibers as generally described in GB-A-2134334 mentioned above, but preferably with the omission of the aforementioned second plastics laminate and metalized laminate. For example the fabric can use a flat pattern (1 above, 1 below) of shrinkable warp fibers of interlaced high density polyethylene of 0.2-0.3 mm in diameter at 3.5 ends per centimeter and glass weave fibers 3 x 68 g / km or 0.1 mm PET monifilaments (2 per yarn) to 3.9 threads per centimeter. The weft fibers will be separated so as not to interfere to an acceptable degree with the shrinkage of the warp fibers. Alternative fabric designs are indicated in the following table.

Preferably, the fabric article includes adherent polymeric material, preferably a laminate of adherent polymeric film (preferably a polyethylene film), which becomes substantially non-porous to the fabric article. For example, a low density polyethylene film of approximately 0.2 mm thickness can be laminated by known lamination methods on one side of the woven fabric. After rolling, the film and the fabric are preferably irradiated by usual means (known per se), preferably up to a dose of at least 10, preferably at least 12, especially at least 14 megarrads, to improve the yield of temperature and the joining of the laminated article. Suitable irradiation methods and equipment, for example electronic beams, are well known. Doses of 20 Mrads are preferably not used and little aggregate advantage is obtained by 15 Mrads dose. The cloth article can become resistant to the transmission of liquids in the plane of the cloth sheet, usually known to make the article "flat hermetic", by methods including those described in EP-A-0324630. In many cases, it will be preferred that the enclosure also enclose a quantity of heat-activatable sealing material capable of flowing to seal the enclosure on heat shrinkage of the fabric article. Such sealing material can be provided separately, although advantageously it will be transported as an adherent layer on the internal confronting surface of the fabric article. Suitable sealing elements are well known, heat-meltable adhesives such as ethylene / vinyl acetate copolymers or polyamides being preferred. The melting point of the sealant or softening point will be selected to suit the temperatures experienced within the enclosure during the heat shrinkage of the fabric article. Preferred sealing materials are mixtures of polyamide and acrylic polymers. The sealant will preferably be selected to maintain the seal (formed on the heat shrinkage of the cloth item in use) when the enclosure is exposed after shrinkage at temperatures up to 125 ° C. For this purpose, it may be preferred that the sealant material be curable after it flows to seal the enclosure to resist further flow at temperatures up to 125 ° C and, preferably at displacements of up to 150 ° C. Examples of adhesives that may be useful for the present purposes are described in WO-A-8707755 (RK310) and in co-pending international application PCT / GB95 / 00731 (B247). Heat-curable adhesives, for example those described in GB-A-2104800 (RK149) and EP-A-0157478 (RK232) may also be useful. The descriptions of those four references are incorporated herein by reference. The fastening of the cloth article around the wiring joint is preferably conducted so that the opposite end regions of the cloth article are held together by the fastening means and each of the end regions is positioned (preferably by folding close to the fasteners). respective ends) so that each cutting part of the fastening means cuts each end region at least twice. Such double-cut arrangements improve the strength of the regions subjected to tearing during the subsequent shrinkage of the fabric. It has been found especially advantageous if one of the end regions is folded and clamped so that its free end projects inwardly from the means of fastening to the joint and wiring. The end projecting inward from the fabric tends to shrink during the contraction of the article to form a compensator between the joint and the cables and the fastening means, thereby helping to keep the fastening means clear of the connection and the cables . This is particularly advantageous when using metal fastening means such as staples. When both end regions of the fabric article are folded inward, they can be joined to form a flat joint with the free ends projecting inwards as mentioned above. However, it is preferred that one of the folded end regions be enclosed by the other to form a cover gasket with the other end region leaving its free end on the outside of the enclosure and extending beyond the fastening means. The desired crease of the end regions can be effected in situ, after winding the cloth member around the joint, holding the overlapping ends of the fabric to form a high four layer fold. Alternatively, the cloth article may be provided with pre-bent end regions, preferably with both end regions folded over the surface of the cloth member which will face inward in use in the enclosure. The folded end regions will preferably not be attached to the part of the teia member adjacent the fold, especially if such a joint would not interfere with the intended arrangement of the regions for fastening. The permanent or semi-permanent folds of the end regions at an angle of less than 180 °, preferably between 90 ° and 180 ° towards the rest of the cloth member (when located flat) are advantageous and, the formation of such folds can be assisted by the weft fibers that act as folding lines through the shrinkable warp fibers. Any of the weft and warp fibers may be the shrinkable fibers, to be wound in the circumferential direction for contraction around the joint, with the other less shrinkable fibers (weft or warp, as the case may be) being located transversally towards the fibers Main contractibles. In many cases, this will mean that the less shrinkable weft fibers (or warp) generally extend along the cables entering and leaving the enclosure. In some preferred forms of the enclosure, the cabling extends substantially vertically through the enclosure and the fastening means cuts the fabric article into at least 2 (preferably at least 3, more preferably at least 4) points throughout. of the wiring to substantially hold the entire length of the cloth member along the wiring. Apart from the simple in-line junctions that have an incoming cable and a cable that leaves the enclosure, the enclosure may have a cable that enters attached to two or three outgoing cables, preferably with the cables that are located substantially parallel to each other by at least inside the enclosure. Any branching of the cables in different directions will preferably occur outside the enclosure, although it could occur within the enclosure, for example with suitable fastening means that cut the fabric between the "ends" of the branched cabling. The fastening means will often be placed in a straight line substantially parallel to the wiring, although other arrangements are possible, for example to follow the design of the diameter change from an individual cable that goes into three or more wires that exit at the joint. A preferred form of fastening means of the present invention is one or more staples or rivets, (especially 10 mm x 10 mm x 10 mm thick approximately 1 mm thick staples), which will usually be made of metal (possibly with a electrical insulating coating), although they can be made of plastic or other suitable insulating material. For practical purposes, the size of the wiring joint will often be such that it can be enclosed by an enclosure in which the width of the fabric article (which is located along the wiring) is within the range of 25 to 50 mm. , preferably 30 to 40 mm. It will usually be preferable that the width of the fabric article be sufficient to overcome the insulation of the wiring beyond the electrically conductive connection itself. For efficiency in use, it is preferred that the substantially complete fastening of the fabric be effected by two staples substantially in longitudinal alignment with one another along the wiring and, preferably substantially substantially uniformly spaced one from the other and from the ends of the enclosure throughout of the wiring.

The invention naturally includes the enclosure after it has been contracted by heat tightly around the joint.

In addition, the invention includes a set of parts for making the enclosure comprising a suitable cloth article and suitable fastening means and preferably includes means for applying fastening means for fastening the cloth member. It has been surprisingly found that the heat shrinkable enclosures in accordance with this invention can pass a severe test in which the enclosure is placed under water and air pressure of 0.5 bar is applied for 60 seconds through the material tube. electrical insulation transported by the cables, the enclosure that passes this test only if there are no air bubbles from the enclosure. The embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which: Figures 1A, 1 B and 1 C schematically show in alternative view alternative folding arrangements of the fabric article of an enclosure in accordance with this invention. Figures 2A and 2B show schematically in extreme view a preferred folding arrangement and a way of forming it for the enclosures in accordance with this invention; Figure 3 schematically shows in perspective a step in the assembly of an enclosure according to this invention around the wiring connections; Figure 4 shows a further step in the assembly of the enclosure of Fig. 3; Figure 5 shows the fastening by staples of the cloth article of Figs. 3 and 4 around the connection wiring; Figure 6 shows schematically the assembled enclosure of Fig. 5 after the heat shrinkage of the fabric article tightly around the wiring joint; Figure 7 shows a branch wiring union with a g rapa fastener between the ends of the branch; Figures 8A and 8B schematically show in cross-section a known form of plastic cable connection in the open and closed positions; and Figures 9A and 9B schematically show an assembled enclosure secured by means of cable joints like those of FIG. 8. Referring to Fig. 1 A, a sheet of fabric 10 as described hereinabove is shown wound around a cable 12 with the insulation 14 entering a connecting connector 16 of any suitable type. The ends 17 and 18 of the fabric sheet have been folded out and are secured in a flat joint by a fastener 19 which passes through a total of four fabric layers, two layers in each of the folded end regions. Figure 1 B similarly shows an end 1 7 folded outwardly and the other end 18 folded inwardly and overlapping the end 17. Figure 1 C similarly shows both ends 17 and 18 folded inward and stapled in one piece. flat seal. The arrangements of Figs. 1A and 1B has the disadvantage that the free ends facing outwardly of the fabric sheet do not form a compensator against the wire. The two free ends facing inwardly in Fig. 1C will tend to form a compensator as described above, although the resulting flat joint may be more prone to spill than a cover joint. A preferred coating gasket is shown in a similar manner in FIG. 2A, where the ends 27 and 28 are folded inwardly as in FIG. 1C, although the end 28 overlies the end 27, which forms the compensator before mentioned. Fig. 2B shows a way to form this preferred arrangement, by first winding the fabric sheet around the joint with the overlapping ends 27 and 28, then gathering the overlapped ends in a fold (dotted lines) to form the disposition of Fig. 2A. Fig. 3 shows the preferred fabric sheet 30 with its ends 32 and 34 pre-bent inward, which have been partially wrapped around a connector 36 to form a joint between a cable entering 37 and two cables coming out 38 and 39 The shape of the connector 36 is not critical. Welded or braided wire connections may be acceptable, without any connector housing as such and corrugations or other connectors, with or without insulating coatings may be used as appropriate.

Fig. 4 shows the sheet of Fig. 3 placed to form an overlap around the joint similar to that described in Fig. 2 and, Fig. 5 shows the enclosure after stapling 50 through the overlapping folds of the sheet. fabric sheet, the woven fibers of which are suggested by the lines 52 (the shrinkable warp fibers surrounded by the joint) and 54 (the glass weft fibers substantially parallel with the wires). Fig. 6 indicates the finished enclosure after shrinking the fabric tightly around the joint and the cables to form a desirably low profile, while keeping the staples 50 at a desirable distance from the cables and the junction under the 34 compensating end of the fabric. Fig. 7 schematically shows a branch connection between a single cable 70 and a pair of branch cables 72, in which a staple 74 cuts the fabric article 73 between the deflected branch cables 72, in addition to the closing clips. subjection 76. Figs. 8A and 8B schematically show a known type of plastic cable joint having a toothed belt 80 that can be wound around an object to be joined and inserted into the body portion 82 (see Fig. 8B), where a flexible retainer 84 engages the tooth 86 for securing the end of the band in the body, thereby holding the joint around the object in question. The projection end 88 of the band (Fig. 8B) can be cut (see Fig. 9B).

Figs. 9A and 9B schematically show cable joints 90 that have been inserted through holes 92 punched in the fabric article 94 in accordance with this invention and secured to hold the fabric article around a wiring joint. The projection end of the joint band (88, Fig. 8B) has been cut by quality.

Claims (18)

1 . A side entry protective enclosure for a connection in a primary electrical wiring, comprising a heat-shrinkable cloth article wound around the joint and fastened around the joint by cloth penetrating fastening means, the cloth article having a circumferential heat shrinkage ratio in the direction surrounding the junction of no more than 50% or is wound loosely enough so that its residual unresolved heat shrinkage ratio after shrinking closely around the junction of wiring is not enough to damage the cloth article, preferably being no more than 50%; and the fabric article having a transverse heat transfer ratio (in the transverse direction to the surrounding direction) that is less than half (preferably less than one third, more preferably not more than 20%) of the ratio of contraction by circumferential heat. An enclosure according to claim 1, wherein the part of the fastening means penetrating the fabric article is separated from the nearest part of the joint or wiring by a distance of up to three times the average diameter (preferably not more than twice the average diameter) of the largest diameter cable (including any insulating layer on it) inside the enclosure.

3. An enclosure according to claim 1 or 2, wherein the fabric article includes adherent polymeric material, preferably a laminate of adherent polymeric film (preferably a polyethylene film), which becomes substantially non-porous to the fabric article.

An enclosure according to claim 3, wherein the laminated fabric article has been irradiated with ionizing radiation up to a dose of at least 10, preferably at least 12, more preferably at least 14 Megarrads.

An enclosure according to any preceding claim, which encloses a quantity of heat-activatable sealing material capable of flowing to seal the enclosure to the heat shrinkage of the cloth article around the joint.

6. An enclosure according to claim 5, wherein the sealing material is conveyed as an adherent layer on the facing surface of the fabric article.

An enclosure according to claim 5 or 6, wherein the sealing material is a heat-meltable adhesive, preferably a mixture of polyamide and acrylic polymers, capable of maintaining the seal formed upon heat shrinkage of the fabric article in the use when the enclosure is exposed after the contraction at temperatures up to 125 ° C and, preferably when it is also exposed to displacements up to 150 ° C.

An enclosure according to claim 5, 6 or 7, wherein the sealing material is susceptible to cure after flowing to seal the enclosure to resist further flow at temperatures up to 125 ° C and, preferably also to displacements up to 150 ° C.

9. An enclosure according to any preceding claim, wherein the opposite end regions of the cloth article are held by the fastening means and at least one of the end regions is positioned (preferably by folding near the respective end) of so that the penetration part of the fastening means penetrates at least one of the end regions at least twice.

10. An enclosure according to claim 9, wherein one of the end regions is folded and clamped so that its free end projects inwardly from the fastening means toward the joint and wiring. eleven .

An enclosure according to claim 10, wherein one of the end regions is enclosed by the other end region having its free end on the outside of the enclosure and extending beyond the fastening means.

12. An enclosure according to any preceding claim, wherein the wiring extends substantially vertically through the enclosure and the fastening means penetrates the fabric in at least 2 (preferably at least 3, more preferably at least 4). ) separate points along the wiring to substantially hold the entire length of the cloth member along the wiring.

13. An enclosure according to any preceding claim, wherein the fastening means are one or more staples or rivets.

An enclosure according to any preceding claim, wherein the width of the cloth article (which is located along the wiring) is within the range of 25 to 60 mm, preferably 35 to 50 mm.

15. An enclosure according to any preceding claim, wherein the cloth article is held by two or three staples substantially in longitudinal alignment with one another along the wiring and preferably, substantially uniformly spaced from one another and from each other. limbs of the enclosure along the wiring.

An enclosure according to any preceding claim, wherein the fabric article has a circumferential heat shrinkage ratio of less than 40%, preferably no more than 35%, more preferably no more than 25%.

An enclosure according to any of claims 1 to 15, wherein the fabric article has a circumferential heat shrinkage ratio greater than 50%, preferably greater than 100%, more preferably 180 to 220a, and is wound in a loose manner as specified in claim 1.

18. An enclosure in accordance with any preceding claim, which has been heat shrunk hermetically around the joint. 20. A fabric article suitable for making an enclosure according to any of the preceding claims, having one or both of its two opposite end regions folded toward the surface of the fabric member that will face inward in the enclosure. 21. A fabric article suitable for making an enclosure according to any of claims 1 to 19, having the fastening means pre-installed in a region ready for fastening to another region of the cloth article. 22. A kit of parts for making an enclosure according to any of claims 1 to 19, comprising a suitable cloth article and suitable fastening means and, optionally including means for applying the fastening means for fastening the cloth member . 23. A method for forming an enclosure according to claim 19, comprising a) winding a length of the cloth article around the joint; b) fastening the cloth article around the joint by means of the cloth penetrating fastening means; and c) heat shrinking the fabric article tightly around the joint.