CA2306056C - A pole - Google Patents

Abstract

The invention relates to a post (1), which is especially a hollow, tube-like piece and which is particularly intended for use as posts for traffic lights, street lights, signposts or similar, and which is formed of two layers.
The inner layer (3) is of fibre-reinforced thermoset plastic and the outer layer (4) is of polyolefin plastic.

Description

A Pole The present invention relates to a post, especially, but not exclusively, a post that can be used, for example, in traffic signs, streetlights, traffic lights and various signposts. Conventional power and telephone posts are naturally one large group forming an application Posts for such purposes are manufactured from many different materials and are generally hollow for many reasons, such as saving material. Various kinds of metal post appear to be the most commonly used. Other aitematives include posts made from reinforced and other plastics. Wooden posts are also in general use.

in certain circumstances, the weight of the post is a significant factor.
Thus, the weight of metal and solid wooden posts is many times that necessary in the intended application. For example, reinforced plastic has been used in an attempt to reduce the weight problem. However, such posts have their own weaknesses, one example of which is shattering during a collision.

This invention is intended to create a post, which eliminates some of the above detriments of posts according to the state of the art to achieve a light and durable post for very many different applications.

According to an aspect of the present invention, there is provided a post for use as a post for traffic lights, street lights, signposts or the like, the post comprising a hollow, tube-like piece which is formed of two layers, wherein an inner layer is of fibre-reinforced thermoset plastic and an outer layer is of polyolefin plastic, wherein the outer layer is a unified and continuous layer, and wherein there is an adhesive material between the inner and outer layers.

1a Thus:

Figure 1 shows a cross-section of one embodiment of a post according to the

2 invention, and Figure 2 shows a longitudinal section of the construction according to Figure 1, and Figure 3 shows a partial cross-section according to Figure 2 of another embodi-ment.

Thus, Figure 1 shows a non-scale diagram of the cross-section of a post 1 according to the invention. The post is specifically hollow, and so contains a longitudinal hollow core 2. The basic construction of the post is double, with an inner layer 3 and an outer layer 4. The thicknesses of these layers 3 and 4 may differ completely from to those shown in the figure.

According to the invention, layer 3 is of fibre-reinforced thermoset plastic and the outer layer 4 is of polyolefin plastic, for example, polyethylene. This kind of construc-tion creates quite a light total structure, which, in addition to the strength given by the inner layer also has the property of a well protected construction, because the outer layer 4 forms a tight, protective layer on top of the inner layer. In a collision, for example, the protective layer protects against damage arising from the shatter-ing of the inner layer, by preventing the shattered material from spreading into the environment with great force.

Figures 2 and 3 show two longitudinal sections with a construction according to the invention. In both constructions, polyofin plastic is used as the outer layer 4, the inner layer being of fibre-reinforced thermoset plastic. In the embodiment in Figure 2, the inner tube has a uniform tubular structure, while in Figure 3, the construction is made of parts, as decribed later in greater detail. In both altema-tives, the tube or tubes may be of uniform thickness or may especially narrow conically.

Thus, Figure 3 shows another embodiment, in which the inner tubular component

3 is assembled from separate tubular part with two or more different diameters, which fit inside each other to form a post construction that narrows in steps.
A
unified polyolefin plastic layer 4 also covers the shoulders that are formed, for example, iri the manner shown at the right-hand side of Figure 3, or more proba-bly, as shown on the left-hand side of Figure 3, i.e. covering the shoulders very tightly.

It is obvious that the layers are drawn separately from each other only for clarity of illustration, as in reality layers 3 and 4 form a solid entity.
It is obvious that many different compositions of thermoset plastic may be used in the manufcture of the inner layer and also that many different kinds of reinforcing fibres may be used, Glass-fibre is the traditional fibre material, but nowadays there TM
are also other very strong fibre materials on the market, such as Kevlar fibre and carbon fibre. From the point of view of the basic idea of the invention, it is clear that both the plastic materials and the fibre materials may be selected according to the intended application.

If necessary, a suitable glue-like or otherwise adhesive substance can be applied between the layers of a post construction according to the invention, which will particularly added between the layers, for example, during the same stage when the outer iayer is extruded on top of the inner layer. The outer surface of the inner layer can also be manufactured in a manner than improves adhesion, such as, for instance, roughening it or using finely crushed material from damaged posts.
All in all, a prefabricated post according to the invention will achieve an extremely useful and durable, but nevertheless light post and thus gain significant advan-tages over the posts in use at present. It has also properties that significantly increase its traffic safety.

Claims (4)

CLAIMS:

1. A post for use as a post for traffic lights, street lights, signposts or the like, the post comprising a hollow, tube-like piece which is formed of two layers, wherein an inner layer is of fibre-reinforced thermoset plastic and an outer layer is of polyolefin plastic, wherein the outer layer is a unified and continuous layer, and wherein there is an adhesive material between the inner and outer layers.

2. A post according to claim 1, wherein the inner layer contains glass fibres, KevlarTM fibres or similar materials and the outer layer is of polyethylene.

3. A post according to claim 1 or 2, wherein the adhesive material is glue.

4. A post according to any one of claims 1 to 3, wherein an outer surface of the inner layer is rough, whereby grip between the inner layer and the outer layer is improved.