GB1412409A - Shock isolators - Google Patents

Abstract

1412409 Hydraulically damped doubleacting spring SHORT BROS & HARLAND Ltd 9 Nov 1972 [17 Dec 1971] 58731/71 Heading F2S A double-acting shock isolator, for a missile launcher, comprises a spring means 1 which yields both under tensile and compressive forces greater than predetermined threshold values applied to the isolator, a hydraulic damper 2, an expansion chamber 25 to ensure that the damper is full of liquid throughout its intended operative temperature range, and restrictor means 30 which provide a permanent connection between the damper and the expansion chamber, and which are so dimensioned as to allow leakage movement of liquid under temperature variations, but to impede the flow of liquid from the damper to the expansion chamber under damping conditions. Filling.-Initially, the chambers 5, 19 and 10 are filled with gas. The chambers 16 and 25 are filled with liquid through a hole 40, a screw cap 35 having been removed to allow a spring 34 to depress a rod 33 and push a valve 29 from its seating. The plugs 41 and 35 are then replaced. Air in the liquid can pass out through the valve 29 and a passage 38 in the cup 35. Compressive shock reaction.-The rod 9 moves into the cap 4 compressing gas in the chamber 5. The piston 23 damps this movement. Tensile shock reaction.-The rod 9 moves downwardly, pulling the cap 4 with it to compress gas in the chamber 19. The piston 23 again damps this movement. Dimensions.-The cap diameter A and rod diameter B are chosen to give the same shock load reaction in each direction of operation. Modifications.-The gas spring may be replaced by a mechanical spring. Several such isolators may be mounted to absorb shocks from several directions.