Patent GB-718516-A (GB)
Title: Radar reflector
Inventor: STEMP VERNON PETER
IPC: H01Q15/20
Filed: 1951-09-26
Abstract: 718,516. Radio reflectors. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Sept. 26, 1952 [Sept. 26, 1951 ; April 24, 1952], Nos. 22469/51 and 10277/52. Class 40 (7)  Relates to a rigid or collapsible radar reflector for use as a survey beacon or for mounting on a buoy: or on the masts of a ship's life-boat or raft, the reflector comprising three mutually perpendicutar square reflecting, sheets, which intersect each other either along their centre lines (multiple covers reflector) or a!ong their diagonals (octahedral reflector). According to the present invention 'the reflecting sheets are attached to three mutually perpendicular rigid circular or square loops. In the rigid embodiment, Fig. 1 (10277/52) and Figs. 2-7 (not shown) three sheets forming an octahedral reflector are built up from a square sheet A, two right-angled isoceles triangular sheets B with flanged bases equal in length to the diagonal of sheet A and four smaller right-angle isosceles triangular sheets C flanged along their right-angled edges which are equal to half the diagonal of sheet A. The corners of all the sheets are removed and they are bolted or riveted together through their flanges along the diagonals of sheet A and the medians of sheets B, the free edges of the sheets being secured in longitudinal slots in aluminium tubular members D, Figs. 6 and 7 (not shown), interconnected by comer castings E to form three mutually perpendicular square frames and the structure being attached to a mast by a boss F attached by arms G to the corners of the framework. The sheets A, B, C may be plain or perforated sheet aluminium.  In the collapsible octahedral reflector, Figs. 1 (22469/51) and 10 and Figs 2-9 (not shown), the reflecting sheets comprise pliable material, e.g. wire mesh or metalized fabric, or hinged thin metal plates and the three frames H, J, K are of different size and are pivoted. together so that the structure can be folded fiat with the frames coplanar and concentric, Fig. 10 and Fig. 2 (not shown), the inner and middle frames H, J being pivoted at corners X, Y and the inner and outer frames H, K being pivoted at comer R, S. Stop plates M and L are provided on the middle and outer frames allowing them to move in one direction only relative to the inner frame and the outer frame K is fitted with spring locking pins in its unpivoted corners which engage grooves in the unpivoted corners of the middle frame J when the structure is erected;; springs may be provided to assist erection. The reflecting surfaces may be formed from two square or four right-angled isosceles triangular shaped pieces of metalized fabric sewn together as illustrated in Figs. 7-9 (not shown), the seams being strengthened with stays of flexible wire or nylon and the eight vertices being fitted with "eyes " for attachment to " eyes " drilled in the stop plates on the middle outer frames and provided at the inside corners of the inner frame. Alternatively the reflecting surfaces may be formed of perforated pliable metal sheets with hinges of coiled wire. The outer frame is also fitted with hoisting "eyes," That its pivoted corners R and S. In a modification (Figs. 5 and 6, not shown) the three frames. are circular.