WO2001086663A2

WO2001086663A2 - Self adhesive cables, conduits and the like

Info

Publication number: WO2001086663A2
Application number: PCT/ZA2001/000057
Authority: WO
Inventors: Peter Trousdale
Original assignee: Peter Trousdale
Priority date: 2000-05-12
Filing date: 2001-05-14
Publication date: 2001-11-15
Also published as: WO2001086663A3; AU6352801A

Abstract

A method of manufacturing a self-adhesive elongate service carrier (14) (defined to include electrical cables of many different types as well as conduits and trunking) is described comprising the steps of conveying an elongate service carrier past an adhesive applicator (16) in order to apply a strip (36) of adhesive longitudinally along its length on one side thereof. A removable protective release sheet (20) is applied to the strip of adhesive on the side thereof opposite the elongate service carrier. The adhesive is preferably a hot melt pressure sensitive adhesive that is compatible with the material of the outer layer of the elongate service carrier. The adhesive generally assumes the surface configuration of the elongate service carrier, one example of which is a conventional electrical flex with the opposite side of the adhesive being generally flat.

Description

SELF ADHESIVE CABLES, CONDUITS AND THE LIKE

FIELD OF THE INVENTION

This invention relates to self adhesive cables, conduits and the like which term is intended to mean electrical cables of many different types including that which is commonly referred to as electrical flex, wires or cable of a generally light weight character, as well as conduits or trunking for receiving such flex, wires and cables together with other service carrying elements and which will be collectively referred to herein as elongate service carriers for ease of description. More particularly, the invention relates to elongate service carriers that are provided an adhesive surface extending along the length thereof whereby they may be adhered to a support surface, typically a wall, floor or ceiling.

BACKGROUND OF THE INVENTION

Self-adhesive cables and conduits find application in a number of industries that presently use separately applied adhesives to secure the elongate service carriers to supporting surfaces. This is a time consuming and messy process that users in industries such as the security and telecommunications industries in particular are required to use.

SA patent No 84/671 to Mommsen describes the use of an adhesive backing that is applied to an electrical cable and by means of which the cable may be secured to a surface, such as a wall. Various types of adhesive backings are described, including double-sided tape, purpose-applied adhesive strips and the use of peal-off protective paper strips. In addition, the patent describes, without illustration, the use of an applicator adapted to combine one or more of the functions of applying the adhesive to the cable, peeling the protective strip off the adhesive and applying the new self-adhesive cable to the surface.

These methods of applying an adhesive layer to the elongate service carriers are, in applicant's view, relatively clumsy and costly.

OBJECT OF THE INVENTION

It is an object of this invention to provide a method and apparatus for applying such an adhesive layer to an elongate service carrier that is more efficient to carry out and which may therefore be used with appreciable cost savings.

SUMMARY OF THE INVENTION

According to one aspect of this invention there is provided a method of manufacturing a self-adhesive elongate service carrier comprises the steps of conveying the elongate service carrier past an adhesive applicator, applying a strip of adhesive longitudinally along the elongate service carrier on one side thereof, and applying a removable protective release sheet to the strip of adhesive on the side thereof opposite the elongate service carrier.

The preferred adhesive is a hot melt pressure sensitive adhesive that is compatible with the material of the outer layer of the elongate service carrier and in the preferred form of the invention, the elongate service carrier is conveyed past a hot melt adhesive applicator, such as a hot melt adhesive gun by means of which the adhesive strip is applied longitudinally along the length of the elongate service caπier

The adhesive strip may be applied as a bead of adhesive, with the cross- sectional shape of the bead being determined, on the side thereof in contact with the adhesive, by the surface configuration of the elongate service carrier. On the opposite side of the bead of adhesive that is covered with the release sheet, the surface is generally flat and optionally formed as two or more parallel coplanar surfaces with grooves or gaps between them

Thus, in the case of a conventional two-core electrical cable or flex with a groove in the outer insulation between the two covered cores, for instance, the bead may conveniently be formed to penetrate the groove on one longitudinally extending side thereof.

In this form of the invention, the bead is preferably formed, by selection of the flow characteristics of the adhesive, to provide a relatively flat, level surface. Such a level surface provides a convenient attachment surface for the removable protective sheet, which may conveniently be applied under a mild pressure when the adhesive is still malleable. This has the effect of spreading the malleable adhesive between the surface of the cable and the protective sheet.

In a variation of the method of the invention, a plurality of elongate service carriers may be conveyed past an equal number of adhesive applicators and a single protective sheet may be applied to all the elongate service carriers, the method including the step of slitting the protective sheet between each pair of adjacent elongate service carriers to provide individual protective strips on each of them.

The invention also provides apparatus for manufacturing a self-adhesive elongate service carrier comprising means to convey an elongate service carrier past an adhesive applicator in order to apply a strip of adhesive longitudinally along the elongate service carrier on one side thereof, and means to apply a removable protective sheet to the strip of adhesive. In a preferred form of the invention the adhesive is a hot melt pressure sensitive adhesive and the applicator is a hot melt adhesive applicator, such as a hot melt adhesive gun that is adapted to apply a strip or bead of hot melt pressure sensitive adhesive longitudinally along the length of the cable.

In the case of a conventional two-core electrical cable or flex with a groove in the outer insulation between the two covered cores, for instance, the adhesive applicator is adapted to form a bead of adhesive that is shaped to penetrate the groove between the two insulated cores of the flex.

The apparatus is conveniently adapted to convey a plurality of elongate service carriers simultaneously past an equal number of adhesive applicators and to apply a single protective sheet to all the cables, the apparatus including means to slit the protective sheet between each of the cables to provide individual protective strips on each of the individual cables.

The invention will be further described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:-

Figure 1 is a diagrammatic side elevation of one form of apparatus according to the invention; Figure 2 is a diagrammatic plan view on a bank of applicators forming part of apparatus of the invention;

Figure 3A,B, and C is a series of diagrammatic sections illustrating sequential steps in the application of a bead of adhesive to a cable in the form of a two core electrical flex;

Figure 4 is an end elevation of a grooved guide plate used in a multi- applicator assembly;

Figure 5 is an end elevation of the bank of applicators illustrated in Figure 2

Figure 6 is a cross-section through a conventional electrical conduit provided with an adhesive strip according to the invention; and,

Figure 7 is a cross-section through a length of conventional trunking provided with an adhesive strip according to the invention.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

In the embodiment of the invention illustrated in the drawings an adhesive application machine (10) is adapted to apply a hot melt pressure sensitive adhesive strip to a cable constituted by a length of two-core electrical flex.

The adhesive application machine (10) comprises a set of drive and driven rollers (12) by means of which a plurality of cables (14) are conveyed past an adhesive application station (16) by means of which a bead of hot melt pressure sensitive adhesive is applied longitudinally along the cables (14) on one side of each of the cables (14). From there the cables (14) are conveyed past a protective sheet application station (18) at which a removable protective sheet (20) is attached to the composite cables (14) to cover the adhesive.

The machine (10) is conveniently adapted to convey a plurality of cables (14) simultaneously through the adhesive application station (16) and to apply a single removable protective sheet (20) to all the cables (14) whilst the cables are still closely adjacent one another. The protective sheet (20) is then slit between each of the individual cables (14) to provide individual protective strips on each of the individual cables thereby allowing individual treatment of each finished cable. In the protective sheet application station (18) the cables (14) are still located adjacent one another in a single plane so that the protective strip can be applied to all the cables (14) as a single sheet (20).

From the protective sheet application station (18), the protective sheet, with the cables (14) thereon, is conveyed through a slitting station (22) where a set of rotating knives (24) slit the sheet (20) into protective strips so that each covers a single cable (14).

This provides a plurality of finished cables (14a) that are adhesive coated and covered with a removable protective strip. The finished cables (14a) can are then wound into rolls or onto reels (not shown) or packaged in some other way for disposal.

The adhesive strips (14) are applied to each cable as a long bead of hot melt adhesive by means of a hot melt adhesive gun (26), each cable (14) having a gun (26) positioned to coat its associated cable (14). In the passage of the cable past the adhesive gun a strip or bead of adhesive is applied longitudinally along its length.

The arrangement of the adhesive application station (16) is illustrated in more detail in Figures 2, 4 and 5.

Figures 2 and 5 illustrate the manner in which the adhesive guns (26) are ganged, by means of an angled support bar (28), over a grooved guide plate (30), the latter being illustrated in sectional detail in Figure 4.

The adhesive guns (26) are relatively wide compared to the width of the grooves (32) in the support plate (30) but by angling the support bar (28) relative to the direction of movement of the cables it is possible to position the placement of the adhesive beads issuing from the adhesive guns adequately close to one another. This enables the use of a relatively narrow single sheet (20), with concomitant reduction in wastage.

During conveyance of the cables (14) through the machine, the individual cables are guided into the grooves (32) formed in the support plate (30). The grooves locate the individual cables accurately beneath the nozzles (34) of the adhesive guns (26) during passage of the cables through the adhesive application station.

The application of the adhesive to the cables is illustrated diagrammatically in Figure 3 in which only a single two-core flex cable (14.1 ) is shown.

In such two-core electrical cables grooves (14.2) are normally formed on either side of the cable between the two insulated cores (14.3 and 14.4).

The adhesive gun nozzles (34) are therefore selected to apply a longitudinally extending bead (36) of adhesive that is shaped to enter the groove between the two cores of the flex as is illustrated in Figure 3A.

As an alternative, the flow characteristics of the molten adhesive can be selected to permit the adhesive to flow into the groove (14.2) while the adhesive is still hot.

Shortly after exiting the adhesive application station, the cable (with the adhesive bead (36) on it) passes through the protective sheet application station (18) where a protective sheet (20) is applied to the cable as is illustrated in Figure 3B. The protective sheet is supplied from a roll (38) and it passes over a series of rollers (40) in order to bring the sheet (20) into contact with the adhesive beads (36) on all the cables (14) passing simultaneously through the protective sheet application station (18), the sheet (20) being sufficiently wide to extend over all of the cables (14).

With the adhesive still relatively hot and malleable, mild pressure is applied to the protective sheet (20) to flatten and spread the bead (36) over the cable (14.1 ) through the configuration shown in Figure 3B to that shown in Figure 3C.

The cable (14.1 ) then passes through the slitting station (22) where the protective sheet (20) is cut into a narrow protective strip (20.1 ) that merely covers and protects the individual cable (14.1 ) as is illustrated in Figure 3C.

The protective sheet (20) is provided with an appropriate release coat on the side that contacts the adhesive, so that it is easy to peal off the adhesive bead (36) as and when required.

The finished cable (14.1a) (which is illustrated in Figure 3C) is then rolled up or wound onto reels for transport, storage and sale. The cable (14.1a) is self-adhesive and simple to use. The protective strip (20.1 ) covering the adhesive (36) is merely peeled from the cable (14.1 ) that can then be applied to a surface in the desired location.

The invention may be equally well applied to many other forms of electrical cable in manner quite apparent to those skilled in the art. Still further, the invention can be applied to other elongate service carriers such as electrical conduits (40), as illustrated in Figure 6, and trunking (41 ) composed of an elongate channel shaped member (42) and a removable cover (43) as illustrated in Figure 7.

Numerous other applications of the invention will be quite apparent to those skilled in the art.

Claims

CLAIMS:

1. A method of manufacturing a self-adhesive elongate service carrier (14) (as herein defined) comprising the steps of conveying an elongate service carrier past an adhesive applicator (16), applying a strip (36) of adhesive longitudinally along the elongate service carrier on one side thereof, and applying a removable protective release sheet (20) to the strip of adhesive on the side thereof opposite the elongate service carrier.

2. A method as claimed in claim 1 in which the adhesive is a hot melt pressure sensitive adhesive that is compatible with the material of the outer layer of the elongate service carrier.

3. A method as claimed in claim 2 in which the hot melt adhesive applicator is a hot melt adhesive gun (34) by means of which the adhesive strip is applied longitudinally along the length of the elongate service carrier.

4. A method as claimed in any one of the preceding claims in which the adhesive strip is applied as a bead of adhesive, with the cross- sectional shape of the bead being determined, on the side thereof in contact with the adhesive, at least to some extent by the surface configuration of the elongate service carrier and wherein the opposite side of the bead of adhesive that is covered with the release sheet is formed to a generally flat configuration optionally as two or more parallel coplanar surfaces with grooves or gaps between them.

5. A method as claimed in any one of the preceding claims in which elongate service carrier is a conventional two-core electrical cable or flex (14.1 ) with a groove (14.2) in the outer insulation between two covered cores (14.3 and 14.4) and the adhesive penetrates the groove on one longitudinally extending side thereof.

6. A method as claimed in any one of the preceding claims in which the adhesive is malleable at application and is spread whilst it is malleable between the surface of the elongate service carrier and the protective sheet by the application of a mild force to the protective sheet.

7. A method as claimed in any one of the preceding claims in which a plurality of elongate service carriers are conveyed past an equal number of adhesive applicators and a single protective sheet is applied to all the elongate service carriers, the method including the step of slitting the protective sheet between each pair of adjacent elongate service carriers to provide individual protective strips on each of them.

8. Apparatus for manufacturing a self-adhesive elongate service carrier (14) comprising means (12) to convey an elongate service carrier past an adhesive applicator (34) in order to apply a strip (36) of adhesive longitudinally along the elongate service carrier on one side thereof, and means to apply a removable protective sheet (20) to the strip of adhesive.

9. Apparatus as claimed in claim 8 in which the adhesive is a hot melt pressure sensitive adhesive and the applicator is a hot melt adhesive applicator.

10. Apparatus as claimed in either one of claims 8 or 9 in which the apparatus is adapted to convey a plurality of elongate service carriers simultaneously past an equal number of adhesive applicators and to apply a single protective sheet to all the elongate service carriers, the apparatus including means (22) to slit the protective sheet between each adjacent pair of elongate service carriers to provide individual protective strips on each of them.

11. Elongate service carriers whenever produced by a method as claimed in any one of claims 1 to 7.