In this specification the term"telecommunication mast"is used to mean a mast structure adapted to mount telecommunication means for receiving, transmitting or relaying telecommunication signals such as radio or other electro-magnetic wave signals.

Conventional telecommunication masts which are disguised as trees are galvanised, painted or otherwise treated against corrosion. Such treatment increases the cost and production time of conventional masts.

It is accordingly an object of the present invention to provide a novel mast which is believed will have certain advantages over conventional units.

According to the present invention there is provided a telecommunication mast comprising an elongate tubular mast member constructed of steel based plate material having a tensile strength of more than 430 MPa and a yield

strength of more than 290MPa; and disguising means secured to the mast member for disguising it in the form of a tree.

The mast member may define a base and an operatively upper extremity, and the mast may taper from the base to the upper extremity. The mast member may have a polygonal cross-sectional configuration, for example a 12 sided polygonal cross-sectional configuration. The mast member may comprise a number of sections which are in use secured to each other in an end to end relationship. Preferably the sections fit into one another spigot and socket fashion.

Preferably the whole of the mast member is hollow and it does not include a cylindrical spine of reduced diameter mounted to the operatively upper extremity of the mast member.

The mast member may include one or more access openings into the hollow mast member. Preferably mast includes two access openings in the hollow mast member, one provided at the base of the mast member and the other provided towards the operatively upper extremity of the mast member.

Preferably a ladder is provided in the hollow mast between the two openings.

Closure means, such as a door may be provided for closing the one or more access openings.

Preferably the mast member is made of steel based plate material which is resistant to corrosion. The material may comprise high strength low-alloy steel which is resistant to atmospheric corrosion. When these materials are exposed to normal atmospheric conditions a tightly adhered oxide patina normally forms on the exposed surface thereof, which very considerably reduces the rate of further oxidation. Materials of this type may comprise the materials known in the trade as BS4360 Grade WR50 and COR-TEN.

Preferably the material comprises COR-TEN.

The mast may include a ladder arrangement towards the operatively upper extremity thereof. Preferably the ladder arrangement comprises a plurality of step formations mounted on the mast member spaced along at least a part of the length of the mast member. Preferably at least some of the step formations extend at least halfway about the mast member.

The plurality of step formations may be provided towards the operatively upper end of the mast member.

Preferably a plurality and more preferably the majority of the step formations extend at least halfway about the mast member. Preferably all the step formations extend at least halfway about the mast member. Preferably the step formations extend substantially fully about the mast member and preferably they extend fully about the mast member. The step formations may comprise ring-shaped members and preferably they extend in a spaced apart relationship about the mast member. One or more connecting members may be provided to extend between each ring-shaped member and the mast member. The ring- shaped members may be made of round bar.

The telecommunication mast may include further means mounted to the step formations. The means may comprise telecommunication means for receiving, transmitting or relaying telecommunication signals. In one embodiment it comprises one or more antennae.

The further means may be directly mounted to at least some of the step formations. Alternatively mounting brackets or the like are employed to mount the further means to at least some of the step formations.

A platform may also be provided towards the upper end of the mast member, preferably just below the step formations.

The disguising means may comprise one or more artificial branches extending from the mast member. The disguising means may also include covering for the mast member to provide it with the appearance of a tree trunk. The covering may be in the form of artificial bark.

Without thereby limiting the scope of the invention and by means of example only, one embodiment thereof will now be further described with reference to the accompanying drawings wherein: Figure 1 is a side view of a telecommunication mast according to the invention; Figure 2 is a side view of the upper portion of the mast of Figure 1; and Figure 3 is a plan view of the mast of Figure 2 sectioned through line m-m.

In the accompanying drawings the same reference numerals are used to denote

corresponding parts.

Referring now to the drawings a telecommunication mast 10 includes an elongate tubular mast member 11 defining a base 12 and an operatively upper extremity 13. The mast member 11 tapers from the base 12 to the upper extremity 13. The mast member 11 includes four sections 11.1 which are secured to each other spigot and socket formation as shown at 14 to form the mast member 11. The mast member 11 has a 20-sided polygonal cross-sectional configuration.

The whole of the mast member 11 is hollow and it does not include a cylindrical spine of reduced diameter mounted to the operatively upper extremity of the mast member 11.

The mast member 11 includes two access openings 15 and 16 therein, one opening 15 being provided at the base 12 and the other towards the operatively upper extremity 13 but spaced therefrom. A ladder [not shown] is provided in the hollow mast member 11 to allow a person to climb up the mast member 11. The openings 15 and 16 may be provided with doors [not shown] for closing them.

The mast member 11 is made of steel based plate material having a tensile strength of more than 430MPa and a yield strength of more than 290MPa. The plate material comprises a high strength low alloy steel known in the trade as COR-TEN which is resistant to corrosion. The use of this material obviates the need to galvanise or otherwise treat it to protect it against corrosion. It will be appreciated that the mast member 11 may still be treated (e. g. painted or galvanised) for aesthetic purposes, but from a corrosion prevention point of view such treatment is not necessary. Masts manufactured from this material are also lighter and less costly to manufacture.

The mast 10 also includes a ladder arrangement 17 provided at the upper extremity of the mast member 11. The ladder arrangement 17 comprises a number of step formations 18 mounted on the mast member 11 spaced along the upper part of the said mast member 11. Each step formations 18 extends fully about the mast member 11. Each step formation 18 comprises a ring shaped member 19 [Figure 3] which extends about the mast member 11 in a spaced apart relationship. Connecting members 20 are provided to extend between each ring shaped member 19 and the mast member 11 to secure the ring shaped member 19 to the mast member 11. The ring shaped members 19

are made of round bar.

Telecommunication means such as antennae 21 are mounted to the step formations 18. Since the step formations 18 extend about the mast member 11 they allow the antennae to be mounted in any position about the mast member 11 and still allowing the portions of the step formations 18 between the antennae 21 to be used as a ladder. It is accordingly fairly easy to adjust the position of the antennae 21 or other telecommunication means [not shown].

The antennae 21 are mounted via brackets 22 to elongate securing members 23 which in turn are secured to the step formations 18, by welding or otherwise.

By securing the antennae 21 or other telecommunication means to the hollow mast member it is not required to provide a cylindrical spine of reduced diameter for mounting the telecommunication means thereto. By eliminating the use of such a spine the problems associated with such a spine, namely fatigue at where it is joined to the mast member 11 and increased labour for mounting it to the mast member 11 is avoided.

A platform arrangement 24 to allow a person to stand on is provided at the upper extremity 13 but below the step formations 18.

The mast 10 also includes disguising means for disguising the mast 10 in the form of a tree. The disguising means includes a number of branches 25 [only the lower parts of which are shown in order not to hide other features of the invention]. Foliage 26 is also attached to the branches 25. The disguising means may also include a covering [not shown] for the mast member 11 to provide it with the appearance of a tree trunk. The covering may be in the form of artificial bark. The branches, foliage and covering may be of the conventional type which may be mounted or secured in the conventional way.

It will be appreciated that the disguising means renders the mast 10 more attractive to the eye and renders it less conspicuous especially in urban areas.

It will be appreciated that many variations in detail are possible without thereby departing from the scope and spirit of the invention.