Patent GB-913546-A (GB)
Title: Improvements relating to reflectors for radio waves
Inventor: JONES-HINTON JAMES
IPC: H01Q15/20
Filed: 1958-05-03
Abstract: 913,546. Radio reflectors. DUNLOP RUBBER CO. Ltd. April 27, 1959 [May 3, 1958; Sept. 25, 1958], Nos. 14199/58 and 30623/58. Class 40 (7). [Also in Group XXXIII] A radio-wave reflector is formed from sheets of flexible reflector material attached to an inflatable structure capable of holding the sheets taut and flat. The structure of the invention is based on a circular disc of reflector material attached round its periphery to a inflatable tube. A number of sheets mounted perpendicular to the disc may form a group of four corner reflectors. Fig. 6 shows a construction in which the disc 23 and a toroidal tube 24 have added further members of flexible reflective material 26 attached to disc along their edges 27 and connected together at 28 to form a group of corner reflectors. The further members 26 are held taut by arched inflatable tubes 31 communicating with the tube 24 and joined at their upper ends; an inflation valve 25 is provided. Instead of providing the tubes 31 four sheets of radiation transparent but air-tight flexible material in the shape of octants of the surface of a sphere may be joined to the curved edges of adjacent members 26 and to the intervening curved edge of sheet 23. The four octants form a hemispherical chamber on the sheet 23 as base and the chamber may be inflated to support the reflector (Fig. 5, not shown). In a further modification, the members 26 are made rectangular and the edges parallel to those attached to sheet 23 attached to a second parallel but radiation transparent sheet kept taut by a second toroidal inflatable tube. The two toroidal tubes are spaced apart by straight inflatable tube sections communicating with them and attached to the outer edges of the rectangular members or by further toroidal inflatable tubes fitting between them (Fig. 7, not shown). Fig. 1 shows a section through a group of four corner reflectors mounted on a reflecting flexible sheet 1 seamed to a transparent sheet 2 and to the outer periphery of an inflatable toroidal support 4. Attached to the sheet 1 are additional reflector members 5 forming four corner reflectors as described above, with reference to Fig. 6. Joining the outer curved edges of the members 5 are octantal sheets 6 of the kind described previously. The quarterhemisphere sections thus produced are interconnected and connected to the space between the sheets 1 and 2 by means of small holes 7 in the sheet 1. Inflation of the contained volume erects the corner reflectors on the sheet 1 and by pressing downwards on the sheet 2, as shown, causes the tie 9 to pull on the corner reflector sheets at point 10 and ensure that they are flat. A corner reflector of this type may be incorporated in the canopy of an inflatable life raft and a suitable arrangement is described with reference to Fig. 3 (not shown). The inflatable tubes and radiation transparent sheets are preferably formed from sheet polyvinyl chloride or other plastic that may be fabricated by heat-sealing. The reflector sheet may be metalized nylon mesh, metal foil or the laminated material described in Specification 913,547.