GB311079A - Improvements in or relating to hydraulic and like shock absorbers - Google Patents

Abstract

311,079. Newton, N. B. April 27, 1928 Fluid - friction vibrationdampers. -An hydraulic shock-absorber for vehicle suspensions &c. has a main non- resilient action and a substantial superimposed or auxiliary resilient action through which the shock is transmitted for absorption by the main action, so that the more rapid and violent movements are absorbed without undue harshness. Means such as a valve is operated by the movement of the auxiliary action to modify the main action proportionally with such movement. The construction shown in Figs. 1 and 2 comprises an outer cylinder a and an inner cylinder c mounted on a boss d in the cylinder head b, a passage d' through the boss being controlled by a regulable valve d<2>. The upper end of the cylinder a is closed by a head e, in which is formed a compensation chamber f isolated from the cylinder by a partition f<1> and a plate valve f<2>. The lower end of the piston rod g carries a main piston h, on which is slidable mounted an outer tubular portion formed of two tubes j<1>, j<2> having an annular space between them substantially equal in cross-sectional area to that of the inner tube. A. bottom plate k of the compound piston is provided with holes m, n, and the side walls of the inner tube j<1> are also provided with holes adapted to be progressively uncovered. A compression spring p is interposed between the bottom plate k and the hollow end g<1> of the piston rod g. The main piston h is formed with an upper boss h' coacting with a central hole o in an upper plate k<1> of the compound piston, a dashpot action being obtained on the return stroke. Holes q in the upper plate k<1> communicate between the upper part of the cylinder and the annular space between the tubes j<1>, j<2>. With the application of a blow, the main piston h moves down, and the tubular portion j<1>, j<2> moves up to a nearly equal extent, thus compressing the spring p and at the same time uncovering some of the holes in the tubular portion, the liquid escaping through the opening o. Thus initially the main force causing displacement of the liquid is transmitted through the spring and increases progressively and proportionally with the relative movement of the piston parts. An additional spring may be interposed between the plate k' and the main piston h. In modifications, a spring or rubber buffer is interposed between a shoulder or abutment on the piston rod and the coupling to the vehicle. Specifications 296,897 and 319,816 are referred to in the Provisional Specification.