GB2276036A - Reflector assembly - Google Patents

Abstract

A reflector assembly comprises an inflatable body and a reflector mounted on the inflatable body such that thereafter is not bound by the inflatable body at its outer limits. The inflatable body preferably comprises spokes between which reflector panels are supported. The spokes preferably have a conical portion tapering away from the centre of the body to intermediate points beyond which the panels do not extend. Guy lines may give additional support to the spokes when inflated. A central region of the inflatable body is preferably a rigid sphere and may contain the source of inflating fluid. <IMAGE>

Description

REFLECTOR ASSEMBLY This invention relates to a reflector assembly for electromagnetic radiation comprising an inflatable body and a reflector mounted on the reflectable body.

Previously, reflectors have been mounted within the inflatable body, either totally within the envelope formed by the inflatable body or inside a frame formed by the inflatable body, which means that the inflatable body must be at least as large as the reflector and will require a correspondingly large amount of fluid to inflate it and a correspondingly large time to allow for inflation. Such a reflector assembly in its operational state provides a relatively large profile to wind and waves.

The present invention attempts to overcome these problems by mounting the reflector at least partially outside the volume defined by the inflatable body. Such an arrangement would be difficult if the conventional spherical inflatable body is used, but in an example of the invention the inflatable body includes a plurality of spokes extending from a central region; it is then possible to mount reflector panels between the spokes, exterior to the central region and the interior of the spokes. The inflatable body does not define a volume between the spokes, since it does not extend between the tips of the spokes. With this arrangement, the characteristics of the forces exerted are reversed compared to the arrangement in which the reflector is mounted within the inflatable body, thus reversing compression and tension forces. This is a much more efficient arrangement since the load capacity of the inflatable spokes is employed directly and not obliquely to support the reflector array.

An example of the prior art and of the invention will now be described with reference to the accompanying drawings in which Fig. 1 shows a prior art reflector assembly with an external inflatable frame, Fig. 2 represents an embodiment of the present invention, Fig. 3 shows a detail of the arrangement of Fig. 2 and Fig. 4 shows another detail of the arrangement of Fig. 2.

The reflector assembly of Fig. 1 employs an inflatable tubular octahedral frame comprising two coupled equal sided tetrahedra having three common edges inside which six isosceles triangular sided, equilateral triangular based tetrahedra reflectors are suspended so that the edges of their bases coincide with the members of the tubular frame.

The reflector panels are thus suspended entirely within the confines of the inflatable frame so that the extent of the frame must be at least as large as the extent of the panels.

Fig. 2 shows an embodiment of the invention in which the inflatable body comprises 12 radial spokes emanating from a central sphere on axes which are displaced at a uniform 600 in any direction from each other. In this example these spokes are conical between the central sphere and an intermediate point along their length after which they continue as cylindrical, and each spoke is formed with a small sphere at its outer end. Guy lines extend from the intermediate points to support the reflector panels and from the small outer spheres for mutual support of the spokes. In this arrangement, the total length of each spoke is 3 metres and the small spheres at its ends have a diameter of 40 cm.

Fig. 4 shows the central sphere formed with a manifold for the spokes. This sphere is rigid, formed from two hemispheres secured together, and contains a canister of gas for inflating the spokes which are affixed to the manifold outlets formed in the surface of the sphere.

Fig. 3 shows a spoke which has a short cylindrical portion at its left-hand end 50 mm long and 160 mm diameter for fitting to a manifold outlet of the central sphere.

Thereafter the spoke tapers to a diameter of 60 mm after a length of 1950 mm to an intermediate point at which rings for guy lines for supporting the reflector panels are affixed to its exterior. Thereafter the spoke is cylindrical for a further 1400 mm length and ends in a 400 mm diameter sphere. Further lugs for guys are provided adjacent the end sphere.

When the reflector assembly is to be made operational, the gas in the canister in the central sphere is released and inflates the spokes thus drawing the guy lines taut as the spokes extend. The guys at the intermediate points on the spokes draw out the reflector panels to their operational positions and the guys at the outer ends of the spokes serve to hold the inflated assembly in its operational arrangement.

The embodiment of the invention has additional advantages in that the tolerances of manufacture and assembly of the spokes are far less stringent since cumulative errors do not develop as they would do in the arrangement of Fig. 1.

Components can be tested individually during manufacture and assembly and replaced without compromising the remainder, whereas failure of a component of an external skeleton arrangement as in Fig. 1 could mean rejection of the complete unit. Furthermore, the arrangement of Fig. 1 cannot conveniently be tested at each stage of assembly.

The quantity of materials with the arrangement of the invention is approximately four times less than that of Fig. 1. The packed volume and weight are therefore correspondingly less. The inflated volume is 2.5 times less for an assembly of corresponding size and hence a smaller gas canister is required. Although this is being described as being located within the central sphere, the assembly could, of course, be inflated from an external source. Since each spoke radiates from the central sphere, inflation is quicker and operates simultaneously throughout the assembly, whereas some of the members of the arrangement of Fig. 1 would only be inflated after the volume of the members between them and the source of inflation had themselves been inflated. The arrangement of Fig. 2 is also easier to pack and there should be less risk of snagging of the guy lines when the system is unpacked and inflated.

Claims (11)

1. A reflector assembly comprising an inflatable body a reflector mounted at least partially outside the volume defined by the inflatable body.

2. An assembly as claimed in claim 1 wherein the inflatable body includes a plurality of spokes extending from a central region, the reflector comprising panels mounted between said spokes.

3. An assembly as claimed in claim 2 wherein the spokes have conical portions tapering with increasing distance from the central region.

4. An assembly as claimed in claim 2 or claim 3 wherein the central region is spherical.

5. An assembly as claimed in any one of claims 2 to 4 wherein the panels extend from the central region only to points intermediate the length of said spokes.

6. An assembly as claimed in any one of claims 2 to 5 wherein a said spoke is formed with a portion of enlarged cross-section at its end remote from the central region.

7. An assembly as claimed in any one of claims 2 to 6 comprising guy lines extending between said spokes.

8. An assembly as claimed in claim 7 wherein guy lines are attached to spokes at said intermediate points adjacent said portion of enlarged cross-section.

9. An assembly as claimed in claim 6 and claim 7 wherein guy lines are attached to spokes.

10. An assembly as claimed in any one of claims 2 to 9 wherein the central region is rigid.

11. A reflector assembly substantially as herein described with reference to the accompanying drawings.