Patent GB-1231036-A (GB)
IPC: F16F9/44
Filed: 1968-08-23
Abstract: 1,231,036. Springs. EFDYN CORP. 23 Aug., 1968 [28 Aug., 1967], No. 40520/68. Heading F2S. A shock absorber comprises a housing 12, Figs. 1, 2, 3, having a primary chamber 14, a parallel secondary chamber 16 and tertiary chambers 18, 20, 22, 24 and 26. The primary chamber 14 is connected to the secondary chamber 16 by ports 28 which are spaced axially and by a passageway 30; the primary chamber 14 is connected to the tertiary chamber 24 by a passageway 32; the secondary chamber 16 is connected to the tertiary chambers 18, 20 by passageways 36, 38 respectively; the tertiary chambers 18, 22 are connected by a passageway 40; and the tertiary chamber 24 is connected to the tertiary chambers 22, 26 by passageways 42, 44 respectively. The chamber 14 has a piston assembly 48 therein which comprises a piston 50 having an annular recess 55 therein and an annular groove 56. The latter communicates with axial ports 58 also in the piston 50, and containing a floating ring 60 therein. The piston assembly is urged forwardly by a spring 61 and has an impact rod 62 which extends outwardly from the housing 12. A floating assembly 70 is also received in the chamber 14 and is urged rearwardly by a spring 80. An adjustable flow control rod 84 is mounted in the secondary chamber 16 and is formed with a lengthwise flat 86, triangular chordal grooves 88 which intersect the flat 86 at the respective locations of the metering ports 28, and an annular groove 90 which is aligned with the passageway 30. The rod 84, having an annular groove 96, is located axially by means of a screw 98 and having a slot 92 is rotatably adjusted by means of a screwdriver. In operation when the rod 62 receives an impact force, the piston assembly 48 moves rearwardly, the floating ring 60 is forced into abutment with the forward side of the groove 56 to prevent flow of fluid past the piston 50; fluid is forced from the chamber 14, through the metering ports 28 and the groove 88 (i.e. orifices), along the flat 86 of the rod 84, around the groove 90, and through the passageway 30 to the primary chamber 14 on the forward side of the piston assembly 48, the floating gland assembly 70 being forced forwardly against the bias of the spring 80. Thus the gland assembly 70 serves as an accumulator when the impact force is removed, the springs 61, 80 return the piston assembly 48 and the gland assembly 70 respectively, the ring 60 abutting the rearward side of the groove 56 to allow flow of fluid past the piston 50, through the recess 55, the groove 56 and the ports 58. At the same time fluid in the chamber 14 on the forward side of the piston assembly 48 is permitted to flow outwardly thereof through the passageway 30. In a modification the lower tertiary chambers 22, 24 and 26 contain cellular members 102, Figs. 5 and 6 (not shown), which preferably are nitrogen filled cells and serve as accumulators. In another modification as shown in Fig. 7 the floating gland assembly and relative spring are omitted and the adjustable flow control rod is replaced by a tubular member 182 which is formed with a number of axially spaced corresponding series of circumferentially spaced orifices 184 and is provided with gear teeth 192 so as to allow rotatable adjustment to be effected by means of a meshing pinion 194. When a particular series of orifices 184 are selected, the pinion 194 is locked by means of a set screw 198.