Patent GB-645163-A (GB)
Title: Shock absorber
IPC: F16F9/516
Filed: 1948-04-07
Abstract: 645,163. Hydraulic shock - absorbers. GABRIEL CO. April 7, 1948, No. 9719. Convention date, May 28, 1947. [Class 108(iii)] In a fluid shock-absorber piston coming a large diameter portion 27 provided with one or more axially-extending peripheral grooves 30, a reduced-diameter portion 28 provided with one or more axially extending grooves or recesses 43, a carrier 51 slidable on the portion 28, a flexible packing ring 50 mounted on the carrier 51 and engaging the cylinder, and means carried by the piston and acting on the carrier 51 with a predetermined pressure to maintain the carrier 51 and ring 50 normally in contact with the end of the piston portion 27 to close the grooves 30, the carrier 51 is so formed as to permit portions of the ring 50 to flex freely away from the piston portion 27 under light fluid pressure, prior to bodily movement of the carrier and ring away from the portion 27 under heavier pressure. In the construction shown, the depth of the grooves 30 is greater at their lower ends and the passages 43 are in the form of eight peripheral grooves. Alternate grooves 43 are connected by respective bores 44 with an inner bore 42 of the portion 28. The bore 42 is connected by a bore 39 with a counter bore in the portion 27. Flow through the bore 39 is controlled by a valve 41a, the seat of which is formed with bleed notches 41. The means acting on the carrier 51 comprises a spring 54 which abuts a plate 45 carried by the piston rod. The carrier 51 has a radiallyextending surface 53 which is formed with upwardly axially displaced portions 53b, and an axially-extending surface 52 having cut-away portions 52a in peripheral register with the portions 53b. The carrier 51 is normally downwardly urged by the spring 54 so that the surface 52 engages the upper end of the piston portion 27 against which the ring 50 is held to close the upper ends of the grooves 30. In operation, on initial downward (compression) movement of the piston, friction between the ring 50 and cylinder wall causes portions of the ring 50 in register with the portions 53b to be upwardly deflected and allow a small flow of liquid from the grooves 30 to the grooves 43. On increased downward piston movement, the ring 50 and carrier 51 are moved bodily to the position shown. On upward (extension) movement the carrier is driven downwardly and the ring 50 contacts the piston portion 27 first, to cushion the impact of the carrier 51 therewith. In assembly of the piston, the plate 45 is fitted in a groove 26 formed in the piston rod by passing the end of the latter through an eccentrically disposed aperture in the plate 45 until the plate is in register with the groove 26. The eccentric aperture is continuous with a concentric aperture of diameter equal to the root diameter of the groove 26. The plate 45 is then laterally displaced so that the concentric aperture engages the groove 26. The piston is then screwed on to the rod so as to clamp the plate 45 against the upper shoulder of the groove 26. Pins 48 upstanding from the piston, register with apertures in the plate 45 so that the eccentric aperture lies in register with one of the recesses 43 and other recesses 43 register with respective apertures 47 in the plate 45.