GB1015368A - Collapsible rod like bodies - Google Patents

Abstract

1,015,368. Aerials. NATIONAL RESEARCH DEVELOPMENT CORPORATION. July 31, 1964 [Aug. 1, 1963], No. 30639/63. Heading H4A. A foldable rod-like body comprises a helix 15, Fig. 1, of closely wound square section spring steel wire fitting closely within and secured to the adjacent ends of two tubular parts 11, 12 (which may be of stainless steel and aluminium respectively and copper plated for improved electrical conductivity) whose spacing apart is such that the length 10 of helix between them is sufficient to permit the parts to be folded together and also to spring substantially into line when released, As described, anchors 13, 14 are held within parts 11, 12 by crimping and serve as abutments for the ends of helix 15. They have lugs 17, 18 extending within the helix carrying pins 19, 21 between which a tension spring 22 is stretched, so holding the parts together and increasing the restoring force when they are folded. A bell-mouthed sleeve 23 lapped over the joint in the unfolded position holds the parts 11, 12 positively in line. It may be pushed back, for folding the parts, against a compression spring 24 which abuts at its other end against a collar 25 fixed to part 12 by a rivet 26. The forward movement of sleeve 21 is restricted either by outwardly tapering part 11 or by providing a positive stop. As applied to an aerial system which may be accommodated in the nose cone of a high altitude rocket, a Langmuir probe 31 may be fitted at the extremity of the body and be connected by a coaxial cable 32 secured by a grub screw 38 with hard rubber button 39, and passing inside the body. Towards the other end of the body the cable is secured to a slidable member 35 by a grub screw 36 and button 37 and is tensioned by a compression spring 34 abutting against another anchor 33, that anchor and anchors 13, 14, being provided with clearance holes for the cable. An external mounting flange 41 is welded to the outside of part 11. A complete system, Fig. 3 (not shown) may comprise three dipoles mounted at rightangles, i.e., one extending axially comprising the rod-like body 42 having one joint 43 and, in association with it, the shell of the rocket, and two dipoles each with two rod-like bodies 44 having two joints 45, 46. The extremities of the rod-like bodies in their folded positions are held by nylon cords 47, Fig. 4 (not shown), each of which is wound on a section of a drum, Fig. 5 (not shown) provided with flanges and a surrounding slotted cylinder. The shaft of the drum is extended on one side and squared for a winding key, and extended on the other side to carry a copper ratchet wheel positioned in the gap of a permanent magnet, for providing eddy-current braking, and held by a pawl which may be released at the proper time. Neoprene protective sleeves 58, Fig. 4, fitting over the metal sleeves associated with joints 46 may actuate microswitch indicators when rod-like bodies 44 are fully extended and other microswitches may be provided to indicate the folded and unfolded positions of all aerial members. The centre joint sleeves may be protected with rubber grommets. The various parts may be mounted on a base 55 made from paper or fabric laminations impregnated with synthetic resin and slots 59, 61 therein may receive the extremities of bodies 42, 44 when folded.