GB739488A - Improvements in or relating to flexible electromagnetic waveguides - Google Patents

Abstract

739,488. Flexible tubes. MINISTER OF SUPPLY. Nov. 27, 1953 [Dec. 1, 1952], No. 30360/52. Class 99 (2). [Also in Group XL (b)] A continuous metallic tube 1, e.g. rectangular in cross-section and of gold, silver or copper or a combination of these metals, has corrugations or undulations 6 extending. transversely of the longitudinal axis thereof and is supported in a body 2 of flexible material adherent to the outer surface of the tube and of natural or synthetic rubber, a synthetic rubber cement such as " Boscoprene No. 551 " (Registered Trade Mark), or rubber tape wound around the tube and bonded with rubber cement. The corrugations may change from concave to convex formation across adjacent sides of the tube, and the body 2 may be reinforced by canvas, cotton or silk fibres or threads, or steel wire incorporated in the body; alternatively, the threads, fibres or wires are helically wound around the tube within or on top of the body. The tube 1 which is used as an electromagnetic wave-guide has, as shown in Fig. 3, each corrugation formed by a radius'R, the centre of which is disposed at a distance R/3 from the mean line of the wall of the tube. In making the tube, a layer of metal is deposited over the silver-mirrored surface of a corrugated mandrel of methyl methacrylate polymer or polystyrene, the mandrel afterwards being dissolved by a solvent and before or after application of the body 2; alternatively, a mandrel of aluminium or a low-melting-point alloy is used. A flash of brass may be deposited over the tube 1 to facilitate adhesion of the body 2.