Patent GB-1319798-A (GB)
Title: Collapsible support structure
Inventor: BURWELL NEIL WORRALL
IPC: H01Q1/08
Filed: 1970-12-18
Abstract: 1319798 Latch fastenings; stud and socket fastenings; resisting pivoting R C A CORPORATION 18 Dec 1970 [29 Dec 1969] 60158/ 70 Headings E2A E2B and E2F [Also in Division H4] A collapsible structure for supporting a pair of rods, such as the halves 11, 12, Fig. 1, of a dipole aerial element, comprises a boom 13 and a pair of support members 16, 17 pivotally secured thereto in opposed relationship. The support members 16, 17 are provided with respective rod-holding portions 23, 43, and also comprise portions which interact with each other when the rods are in their operating positions, so adding rigidity to the structure. In their collapsed positions, the rods are substantially parallel to the boom. As described, the two support members are identical and are made of a resilient, plastic, insulative material, such as polypropylene. They are disposed on opposite sides of a rectangular crosssection boom, and are pivoted by means of a rivet 14 which passes through the boom and is made off on washers 18, 19. Considering the support member 16, the rod holding portion 23 extends perpendicularly to the axis of the boom 13 in the operating position, and is symmetrical thereabout. The rod 11 lies in a channel 33, having overlapping sections 31, 32, and is secured by means of a bolt 29. On the other side of the pivoting axis a locking member 24 extends, having tabs 26, 27. Bracing members 22, 25 connect the member 24 and the portion 23. As shown, the member 24 bears down on the upper face of the boom 13, and the tabs 26, 27 lie on either side thereof, and prevent rotation of the member 16 about the rivet 14. A leg member 61 extends from the member 16 at one end of the portion 23 and has a foot-like segment 63 which is received in a groove 74 in the member 17. At the other end of the portion 23 of the member 16 a groove 64 is provided, in which a foot 73 of a leg member 71 of the member 17 is received. To collapse the rod 11, the locking member 24 is lifted until the tabs 26, 27 are clear of the boom 13, when the rod and the support member are rotated in a clockwise direction until the rod is along and parallel to the boom. Similarly with the rod 12, the rotation in this case being anti-clockwise. The grooves 64, 74 extend through the members 16, 17 and in order to prevent over running when extending the rods, pivoting stops 81 may be provided. In another embodiment, an array of parallel dipoles is mounted on a boom 95, Fig. 4, and is fed from a two-conductor transmission line 110, 111. Each conductor is channel-shaped and is supported at each dipole by an insulating assembly 140 in which a tubular spacer 141, Fig. 5, is sprung below a pivot pin washer, the conductor flanges are positioned in slots provided, and a cap 142 is sprung over the spacer. A small riser extending from the centre of the cap 142 rests against the conductor 110 or 111. Each dipole half is connected to the appropriate conductor of the transmission line by a flexible strip 135 or 145. The dipoles are arranged along the boom so that on either side thereof successive halves are disposed alternately on its upper and lower sides, thus preventing interference between said halves when collapsed (Fig. 3, not shown). Furthermore, if the spacing between the dipoles is a half-wavelength, transpositions equivalent to 180 are obtained. If a dipole is required to function parasitically, it may be connected to the boom instead of to the tranmission line.