GB2139116A

GB2139116A - Portable road markers

Info

Publication number: GB2139116A
Application number: GB08408179A
Authority: GB
Inventors: Henry Dennis Cronk
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1980-10-17
Filing date: 1981-10-16
Publication date: 1984-11-07
Also published as: GB2139116B; GB8408179D0

Abstract

A reflective sheet blank - e.g. for forming a frusto-conical sleeve attachable to a road marker cone - is provided on its reverse surface with a discontinuous pressure sensitive adhesive defining a grid pattern (10) delineated by non-adhesive areas (12) projecting slightly above the level of the adhesive (10). Once roughly located on the road cone, the grid pattern (10) permits the sleeve to be shifted before pressure applied on the grid areas finally secures the sheet in place. In manufacture, the entire face of the sheet blank may be coated with adhesive and then covered with a liner material scored along lines defining a grid pattern, whereafter the grid of liner material is removed to leave small pieces of liner material which form the projecting non-adhesive areas (12). <IMAGE>

Description

SPECIFICATION Traffic cones This invention relates to traffic guidance systems and more particularly to bollards of cylindrical or conical design.

In recent years, there has been a need for providing a traffic bollard, particularly those which are portable, with a visible surface area of which at least a portion is reflex- or retro-reflective. Portable bollards are typically moulded in plastics materials and while suitable reflective sheet materials are known, the application of such materials to curved surfaces of the bollards in a secure manner has always been a problem. This is especially true in the case of conical bollards where a frusto-conical section of the bollard must be covered. The adhesive used must of necessity be aggressive and this can result in the applied sheet being clumsily secured. The consequence is an imperfect product from which the reflective material can become detached because of insecure adhesion.

An exact match between the reflective material and the bollard is desirable for the above reasons and also where the material is to be applied to a cylindrical bollard. As the precise dimensions of bollards, both cylindrical and conical, vary substantially, this exact matching of the reflective material to bollards is difficult to achieve on a commercial manufacturing scale.

In an attempt to mitigate the above problems, Application No: 81 31339 contemplates the use of a reflective material in the form of a continuous strip which is wound round and adhesively secured to the chosen surface area. According to that invention, a method of providing a reflective surface on at least a portion of a traffic bollard comprises providing a flexible adhesive backed tape having a reflective surface and a width to stretchability ratio not greater than 1.2 wherein the width is measured in millimetres and the stretchability is measured as the percentage elongation at break; and helically winding the tape in a plurality of complete turns round at least a portion of the bollard, and adhesively securing the tape to the external surface of the bollard.

The tape is sufficiently flexible to bend in its own plane over a wide range of surface contours without wrinkling and without impairing its inherent reflectivity. We have found that a retro-reflective material can be adapted to fulfil these requirements by selecting a suitable range of tape widths and stretchabilities. The ratio of width to stretchability is preferably as low as possible. Reference is directed to Application No: 81 31339 for further details of the above technique, and of apparatus for applying it.

The present invention is concerned particularly with the first problem discussed above; namely that of clumsy securement of reflective sheet materials to bollards. According to the invention a sheet of reflective material shaped for adhesive securement to a predetermined surface area, has a pressuresensitive adhesive in the form of a grid on one face thereof, the grid being delineated by areas on the face projecting above the level of the adhesive. In use, this sheet may be located on the receptor surface, and slid around on the projecting areas until the precise position is found. At that point, the lines of adhesive may be pressed against the receptor surface to secure the sheet in place. Typically, in the manufacture of the sheet, the entire one face thereof is coated with adhesive, smaller pieces of liner or other material being secured thereover to define the projecting area.A linear material is usefully employed as this may have the grid marked out on it with score lines, the whole one face of the sheet being initially covered at the manufacturing stage to protect the adhesive, and the grid alone being removed prior to application of the sheet to the receptor body.

The invention will now be described by way of example and with reference to the accompanying drawings wherein Figure lisa perspective view of a common form of conical bollard with a reflective coating thereon; Figure 2 shows a perspective view of a frustoconical sleeve for forming the reflective surface on the bollard of Figure 1; and Figure 3 shows a developed view of the sleeve of Figure 2 with a grid of adhesive formed thereon in accordance with the invention.

The bollard shown in Figure 1 is typical of many in current use. It comprises a conical portion 2 mounted on a square base 4. Such bollards are commonly integrally moulded in a plastics material.

An area 6 of the cone 2 is provided with a reflective coating, which is normally in the form of a sleeve dimensioned to match the cone.

Bollards of the type illustrated in Figure 1 are produced in many different sizes, the overall height being normally not greater than 1300 mm and the included apex angle a of the cone generally not exceeding 20 . The height of the reflective sleeve is usually not greater than 530 mm and may comprise a plurality of narrow bands of as little as 10 mm. The cone cross-section need not always be circular either; bollards of this general type are also available with polygonal such as triangular or square crosssections. Further, cylindrical or tubular bollards having a region of uniform cross-section are also in common use for example on motorways.

Figure 2 shows a perspective view of a conical sleeve of reflective material for application to a bollard of the type shown in Figure 1.

It will immediately be appreciated that with exposed adhesive on the inner surface thereof, precise location and securement on a cone is difficult if not impossible. The sleeve is formed into a frusto-cone from a shaped blank and welded along the seam 8, so neither is the removal of a release liner an easy exercise either. It is though sometimes permissible to apply the material without first forming a frustocone. However, this requires very precise initial location of the blank on the cone.

A sheet material according to the invention for application to a cone of the kind shown in Figure 1 is shown in Figure 3. A sheet blank is formed with a grid of adhesive on the reverse face thereof as shown. The lines 10 of the grid are delineated by islands 12 formed by pieces of liner or other material adhered to the blank by means of the same adhesive that is exposed along the lines 10. The blank can then be loosely located on the cone and slid into precise position before applying pressure to the grid lines 10 to secure it in place. If desired, the blank may first be formed into a sleeve as shown in Figure 2.

Although this technique suffers from a certain lack of flexibility, as each blank or sleeve must be matched to the bollard to which it is to be applied, this can be acceptable in some circumstances, and where large numbers of identical bollards are to be produced, the technique can be economic and efficient.

Claims

1. A sheet of material for adhesive securement to a predetermined surface area, having a reflective surface on one face thereof and a pressure sensitive adhesive on the other face in the form of a grid delineated by areas on said other face projecting above the level of the adhesive.

2 A sheet of material according to Claim 1 wherein said areas are defined by pieces of liner material.

3. A sheet of material according to Claim 2 wherein the grid is revealed by removal of a liner material from the lines thereof.

4. A sheet of material for adhesive securement to a predetermined surface area, having a reflective surface on one face thereof; a layer of pressure sensitive adhesive on the other face thereof, and a liner covering the adhesive layer, the liner being scored to define a grid thereon, the portions of the liner defining the grid being removable from the adhesive layer in preference to the remaining portions.

5. A sheet of material for adhesive securementto a predetermined surface area substantially as described herein with reference to the accompanying drawing.