The invention relates to an elongate tubular member, and especially an elongate tubular member for use as a structural member, such as a

scaffolding tube or pole.

Traditional scaffolding tubes are manufactured from metal poles which are usually steel and often galvanised to provide some protection from corrosion. While traditional steel tubes provide structural strength, they are relatively expensive to manufacture and difficult to recycle.

In addition, metal scaffolding has particular problems when used in hazardous environments, such as close to overhead electric power lines. In this case the metal scaffolding presents problems because it is an inherent conductor of electricity and there is a risk of electrocution to installers of the scaffolding or workers on the scaffolding if the scaffolding contacts the power lines. There is also a risk of shorting the overhead power cables if metal scaffolding touches them. An example of where this can be a serious problem in practice is where elevated access is required beside or on railway track that uses electrified overhead power lines. The use of metal scaffolding may also be problematic in situations in proximity to explosive substances. In this case there is a risk of metal scaffolding causing a spark if it is accidentally struck with another metal object, such as a hammer or part of the scaffolding accidentally strikes another object during installation of the scaffolding.

Therefore, although metal scaffolding is structurally strong, there are situations where it is preferable not to use metal scaffolding or metal scaffolding simply cannot be used, for example, due to health and safety considerations.

In accordance with the present invention, there is provided an elongate member comprising a tubular outer member; a tubular inner member spaced from and within the outer member, the inner member extending along the outer member; and a number of first members extending between the outer member and the inner member to locate the inner member within the outer member.

An advantage of the invention is that enables an elongate tubular member to be made from a non-metallic material, such as a plastics material, and to also have a load bearing capacity comparable with a metal tube having the same outer diameter. This particularly useful where the elongate tubular member is a scaffolding tube.

Preferably, a number of second members extending inwardly from the tubular inner member and intersecting with each other within the inner member. Typically, the number of second members is less than the number of first members.

Typically, the tubular inner and outer members extend substantially parallel along a central longitudinal axis of the elongate member.

Preferably, the tubular inner and outer members are substantially concentric.

The tubular outer member may have a substantially circular cross-section. The tubular inner member may have a substantially circular cross-section.

Preferably, the first members extend substantially radially between the inner and outer members. The first members may be spaced substantially equidistantly around the inner member. In other words, the first members may be spaced equidistantly around the tubular inner member in a plane perpendicular to the longitudinal axis of the elongate member.

Typically, the tubular outer member has a greater wall thickness than the tubular inner member.

The gap between the inner wall of the tubular outer member and the outer wall of the tubular inner member may be less than the gap between the inner wall of the tubular inner member and the central longitudinal axis of the tubular inner member. Typically, the thickness of the first members is less than the thickness of the tubular inner and outer members. Preferably, the first members extend along the length of the inner and outer members.

The second members may extend substantially radially inwardly from the tubular inner member. The second members may intersect on a central longitudinal axis of the tubular inner member.

Typically, there are four second members. The second members may be spaced equidistantly within the inner member around the longitudinal axis of the elongate member. In other words, the second members may be spaced equidistantly around the longitudinal axis in a plane perpendicular to the longitudinal axis.

Preferably, a diameter of the elongate member that coincides with two diametrically opposite second members does not coincide with any of the first members. A radius of the elongate member that is coincident with one of the second members may bisect an angle between two adjacent first members.

The second members preferably extend along the length of the inner member. The thickness of the second members may be less than the thickness of the tubular inner and outer members.

Preferably, the elongate member is formed from a non-metallic material, such as an insulating material. The elongate member could be formed from a plastics material, for example high density polyethylene (HDPE). The elongate member may be manufactured from a recyclable material.

Typically, the elongate member is formed by a moulding process, such as an extrusion moulding process.

The elongate member may be a scaffolding tube.

An example of an elongate tubular member in accordance with the invention will now be described with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of a first example of an elongate tubular member for use in scaffolding;

Fig. 2 is an end view of the tubular member shown in Fig.1 ;

Fig. 3 is a cross-sectional view of the tubular member along the line AA of Fig.2;

Fig. 4 is a perspective view of a second example of an elongate tubular member for use in scaffolding; and

Fig. 5 is an end view of tubular member shown in Fig. 4. Figs. 1 to 3 show a first example of an elongate tubular member 1 formed from a tubular outer member 2 and a tubular inner member 3. The tubular outer member 2 and the tubular inner member 3 both have a circular cross- section and are concentric with each other about a central longitudinal axis 4.

The tubular inner member 3 is mounted within the tubular outer member 2 by means of eight connecting members 5 that extend radially inwardly from an inner wall 6 of the tubular outer member 2 to an outer wall 7 of the tubular inner member 3. The members 5 also extend in a direction parallel to the axis 4 along the length of the outer and inner members 2, 3 from a first end 8 to second end 9 of the elongate tubular member 1.

In the example shown in the drawings there are eight first connecting members 5. However, the number of connecting members 5 could be more than eight or less than eight, depending on the particular application for the elongate member 1 and the required strength of the elongate tubular member

1 .

Within the tubular inner member 3 are four second connecting members 10 that extend radially inwardly from inner wall 11 of the tubular inner member 3 and intersect with each other at the central longitudinal axis 4. The second connecting members 10 also extend the length of the tubular outer and inner members 2, 3 from the end 8 to the end 9. Although in the example shown there are four second connecting members 10, the number of second connecting members 10 could be more or less depending on the particular application and the required strength of the elongate tubular member 1.

Similarly, although one tubular inner member 3 is shown, there could be more tubular inner members 3 depending on the particular application and the required strength of the elongate tubular member. In the elongate tubular member 1 , the tubular inner and outer members and the connecting walls 5, 10 are preferably integrally formed with each other.

Preferably, the elongate tubular member 1 is manufactured from a plastics material and may be formed by a moulding process, such as an extrusion moulding process. However, it could be formed using any suitable

manufacturing process. An example of an alternative manufacturing process that could be used is a 3D printing process. The inventor has found that by forming the elongate tubular member 1 from a plastics material, it is possible to design the elongate tubular member with sufficient strength and rigidity for it to be used as a scaffolding tube in place of conventional steel scaffolding tube and having the same nominal outside diameter as a traditional metal scaffolding tube. Although the elongate tubular member 1 is manufactured from a plastics material, the structure of the elongate member 1 , as described above with tubular outer and inner members 2, 3 and first and second wall members 5, 10, is such that it can be designed to have sufficient strength to be used as a scaffolding tube.

Preferably, the elongate member 1 is manufactured from a recycled plastics material, such as recycled high density polyethylene (HDPE). For example, for use as a scaffolding tube and manufactured from HDPE, the elongate member 1 can have a length of 3000mm, a nominal outer diameter of 48.3mm with the tubular outer member 2 having an internal radius of 20.15mm and the tubular inner member 3 having an outer radius of 16.15mm and internal radius of 13.15mm. These dimensions result in the tubular outer member 2 having a wall thickness of 4mm and the tubular inner member 3 having a wall thickness of 3mm.

Typically, the wall thickness of the tubular outer member 2 is greater than the wall thickness of the tubular inner member 3 and the thicknesses of the first and second connecting members 5, 10 is less than the wall thicknesses of the tubular outer and inner members 2, 3.

Figs. 4 and 5 show a second example of an elongate tubular member 20. The tubular member 20 is similar to the tubular member 1 and the same parts are indicated using the same reference numerals. The difference between the tubular member 20 and the tubular member 1 is that the tubular member 20 has second wall members 21 that are not aligned with any of the first wall members 5. This contrasts with the tubular member 1 , in which each of the four second wall members 10 are aligned with a first wall member 5. In the arrangement shown in the tubular member 1 , a diameter of the tubular member 1 that coincides with diametrically opposite second wall members 10 will also coincide with two diametrically opposite first wall members 5. Whereas in the tubular member 20, a diameter that coincides with two diametrically opposite second wall members 21 will not coincide with any of the first wall members 5. In addition, it is preferable that a central axis 23 of each second wall member 21 bisects an angle 22 between two adjacent first wall members 5.

The advantage of the tubular member 20 is that promotes better flow of material during the extrusion moulding process and a finished tubular member 20 that is less prone to defects. When the elongate tubular members 1 , 20 are formed by an extrusion moulding process using HDPE and having the above dimensions they will typically have a 1 tonne loading capacity and can be used as scaffolding tubes in place of conventional steel tubes having the same nominal outer diameter. An advantage of the invention is that it enables scaffolding tubes to be manufactured from a non-metallic material, such as an insulating material, for example, a plastics material, and still have the structural strength of a traditional metal scaffolding tube. This makes it possible to use scaffolding erected using the elongate tubular members 1 formed from a non-metallic material, such as a plastics material, in hazardous environments.

Another advantage is that if the elongate tubular member 1 , 20 is

manufactured from a recyclable material, such as a plastics material, for example HDPE, it is possible to recycle the elongate tubular member 1 , 20 when it reaches the end of its useful life.