Patent GB-570214-A (GB)
Title: Improvements in or relating to a shock absorber
IPC: F16F9/44
Filed: 1943-02-17
Abstract: 570,214. Hydraulic shock-absorbers. MONROE AUTO EQUIPMENT CO. Feb. 17, 1943, No. 2668. Convention date, Dec. 30, 1941. [Class 108 (iii)] In a hydraulic piston and cylinder shockabsorber for vehicles, a predetermined stage of resistance to compression and rebound is provided by means carried respectively by the cylinder and by the piston, both means being adjustable simultaneously by further means to increase the resistance. The shock-absorber shown comprises a cylinder A surrounded by a reserve chamber B formed by the cylindrical portion 8 of a casing 9 having an upper end closure 11, through which slides the piston-rod D, and a lower end valve assembly 12. The head 51 of the piston C contains two circular series of passages 53, 54, flow of liquid through which is controlled respectively by a laminated leaf spring valve 60 and a disc valve 55, the latter valve having a slot 56 registering with the passages 53 to permit free flow of liquid therethrough and an edge portion 57 normally held by a star-shaped spring 59 in closed position over the passages 54. The valve 60, which normally closes the lower ends of the passages 53, is clamped between the head 51 and a sleeve 52 threaded on the reduced portion 50 of the piston-rod. A nut 71 having downwardly-opening slots 73 is threaded on the sleeve 52, while loosely mounted on the sleeve 52 between the nut 71 and the valve 60 is a slide 74 which, when urged upwardly by the nut 71 against the valve 60, stiffens the resistance of the valve. The valve assembly 12 at the lower end of the cylinder A comprises a body 16 rigid with the cylinder and containing two circular series of passages 17, 18, flow of liquid through which is controlled respectively by valves 25, 24 similar respectively to the piston valves 60, 55. A bolt 19 and sleeve 21 extend through the body 16 and a cup-shaped slide 26 is slidable on the lower end of the bolt and on a flange 30 on the sleeve and when moved upwardly engages the valve 25 to stiffen its resistance. The sleeve is interiorly threaded at its.lower end on the bolt and carries a nut 23 at its upper end. A washer 31 non-rotatably mounted on the upper end of the bolt 19 has diametrically-opposed, upturned tongues 32 adapted to engage in the slots 73 in the nut 71 of the piston assembly when adjustment of the shock-absorber is to be effected. On compression of the shock-absorber, liquid flows through the piston passages 54, past the valve 55 to the space above the piston and liquid also flows through the passages 17 in the valve assembly 12 past the valve 25 to the reserve chamber B. On extension, liquid flows through the piston passages 53, past the valve 60 to the space below the piston and from the reserve chamber B through passages 34 in the body 16, the passages 18 and past the valve 24 into the cylinder A. To increase the resistance of the valves 25, 60, one or other of the heads 41, 42 connecting the ends of the shock-absorber to its supporting brackets, is detached and the shock-absorber compressed until the tongues 32 of the washer 31 enter the slots 73 in the nut 71. The heads 41, 42 are then rotated relatively to one another, causing the piston assembly to rotate relatively to the valve assembly 12, thus effecting relative turning movement between the nut 71 and sleeve 52 to move the slide 74 against the valve 60 and between the sleeve 21 and bolt 19 to move the slide 26 against the valve 25. Hence, the resistance offered by the valves 60, 25 is increased. Two modifications of the base valve assembly 12 are shown, in one of which the resistance offered by the valve 25 is increased, on relative rotation of the parts, by compression of a coiled spring, the lower end of which rests on the head of the bolt 19, while the upper end bears against a ring in contact with the underside of the valve.