GB648721A - Shock absorber - Google Patents

Abstract

648,721. Hydraulic shock - absorbers. GABRIEL CO. April 7,1948, No. 9720. Convention date, May 28, 1947. [Class 108(iii)] In an hydraulic shock absorber having a piston portion 33 of larger diameter slidable in a cylinder 22 and having peripheral passages 33b extending between its ends, and a portion 34 of smaller diameter radially spaced from the cylinder, a resilient packing ring 50 being mounted on the piston portion 34 and engaging the cylinder and being movable relative to the portion 34 to a position in engagement with the portion 33 and closing the passages 33b on the recoil stroke, and from such position on the impact stroke, spring means 52 acting on the ring to maintain it in the passage-closing position until the creation of a predetermined pressure on the impact stroke, means is carried by the piston for adjusting the spring means 52. The periphery of the piston portion 34 is formed with a series of circularly-shaped axial grooves 43, alternate grooves being connected by respective bores 44 with an inner bore 42 of the portion 34. The remaining grooves 43 terminate -at 43a. The bore 42 is connected by a bore 39 with a counterbore 36 in the portion 33. The piston rod has a groove 32 for a plate 45, Fig. 4, which has a concentric aperture a of equal diameter to that of the base of the groove 32. The aperture is continuous with an eccentric aperture b of larger diameter than that of the piston rod by means of which the plate may be slipped over the rod. Pins on the piston register with holes 49 in the plate 45 so as to position the latter with the eccentric aperture overlying certain of the grooves 43, while further apertures 47 in the plate overlie other grooves 43. A ring 53 (Fig. 5) is positioned beneath the plate 45 and has diametrically opposed upstanding portions which are equal in peripheral length, and may lie within recessed portions 45b of the plate 45. Each upstanding portion is composed of cam surfaces 61, 63, surfaces 62, 64 upwardly offset and parallel with the upper surface 53a of the ring, and upwardly projecting lugs 65. The lower surface 53b of the ring 53 forms an abutment of the spring 52 which acts on the packing ring 50 through a carrier member 51. The lugs 65 are engageable with respective recesses in the upper head of the cylinder 22 so that on full extension of the piston rod and rotation thereof relative to the cylinder, the ring 53 is rotated relative to the piston. Thus, any one of the surfaces 53a, 62, 64 may be selected to engage the lower surface of the plate 45 and produce a corresponding adjustment of the spring 52. Flow through the bore 39 is controlled by a valve 56, the seat of which is formed with bleed grooves 41. Adjustment of the pressure of a loading spring 57 of the valve 56 is effected by rotation of a cup-shaped member 54 threaded in the counterbore 37. This is effected when the shock absorber is fully collapsed, lugs 58a of a member 58 in engagement with the member 54, engaging respective recesses in the lower head (not shown) of the cylinder 22.