GB458311A - Improvements in or relating to shock absorbers or vibration dampers - Google Patents

Abstract

458,311. Shock - absorbers. TECALEMIT, Ltd., and CHALMERS, R. A., Great West Road, Brentford, Middlesex. June 21, 1935, No. 17835. [Class 108 (iii)] During both expansior and contraction of a shock absorber, particularly for vehicles, fluid is displaced by reciprocatory means from an inner chamber into an outer chamber and always passes in the same direc, tion through one or more restricting passages dis posed at that end of the inner chamber towards which the reciprocatory means moves when the shock absorber is expanding the fluid flowing in a closed circuit. As shown the shock. absorber comprises concen. tric cylinders 1, 5, an apertured piston 13 carrying non-return valves 23, 24 adapted to reciprocate in the inner cylinder 5, and a member 25 fixed in the upper end of the cylinder 5 and containing fluid-restrict. ing passages 32, 33 commu. nicating through an annular groove 34 with ports 35, 36 in the cylinder 5. In operation, on movement of the piston and piston-rod 15 in either direction liquid is forced through the passages 32, 33, groove 34, and ports 35, 36 to the annular space 12, and on upward movement of the piston liquid is also sucked in from the space 12 through a non-return valve 10 in a cap 2 closing the lower ends of the cylinders. Leakage of liquid from the upper end of the cylinder 5 is prevented by a gland 50 held in position between a scraper ring 30 and a washer 29 against which bears the upper end of a spring 28. The spring may also act on a washer 42 in contact with a valve-pin 38 which normally closes a port 40 but which opens against the action of the spring to prevent excess pressure in the shock-absorber. To prevent aeration of the liquid leaving the cylinder 5 a tube 43 fixed to the cylinder above the ports 35, 36 directs the liquid to the bottom of the space 12. Alternatively the tube may be replaced by two open-ended pipes. As shown, the cross-sectional area of the piston-rod 15 is equal to half that of the bore of the cylinder 5, so that equal quantities of liquid flow through the passages 32, 33 on equal up and down strokes of the piston. By varying the crosssectional area of the rod, the quantities of liquid may be varied. To vary the resistance interchangeable members 25 having passages 32, 33 of different diameters may be used or the valves 23, 24 may be loaded by adjustable springs or by springs of varying strengths. In another construction the fluid-restricting passages are replaced by ports controlled by spring-pressed valves. Specification 436,845 is referred to.