Patent GB-440405-A (GB)
Title: Improvements in hydraulic shock dampers
IPC: F16F9/26
Filed: 1934-04-27
Abstract: 440,405. Controlling shock-absorbers. LESLIE, I. A., Highfield Lawn, Highfield Road, Derby. April 27, 1934, No. 12736. [Class 108 (iii)] A vehicle hydraulic shock-absorber is so constructed that road-wheel displacement of the vehicle automatically increases the resistance of the shock-absorber proportionately to the extent of the wheel-displacement, hydraulic locking means being provided which maintain the increased resistance during the return movement of the wheel, the locking means comprising two interfitting members one of which is axially movable relatively to the other and mechanically connected to the means loading the controlling damping valve or valves, while one or more spaces between the members are in communication with a compression chamber the liquid in which imposes a radial thrust on the members to prevent their relative axial movement during the return movement of the wheel. In the double-acting shock-absorber shown in Figs. 1, 2 displacement of the piston d<2> in either direction forces liquid from one compression chamber d or d<1> to the other past a valve g which is lifted against the action of a spring g<4> pressing against a slidable cap g<5>. In order to increase the resistance of the valve g and therefore of the shock-absorber, the cap is adapted to be moved to the left by a boss h<6> on a lever h<5> rigid with a lever h<4>, Fig. 2, which carries a pin h<3> engaging a slot h2 in a link h<1> pivoted to an arm h which is rigid with the shaft b<2> carrying the arm c<2> operating the piston d<2>. The lower end of the lever h<5> is pivoted to a flexible rod slidable in a conduit j<1> in the shock-absorber casing. On movement of the piston d<2> in either direction the lever h<5> is moved clockwise to compress the spring g<4> and at the same time liquid is forced through a hole k or through holes k<3>, k<2>, k<1> into a space between a flat j<3> or j<2> on the rod j and the conduit j<1>, thus locking the rod and therefore maintaining the spring g<4> under compression and the resistance of the shock-absorber at the maximum, the pin-and-slot connection h<2>, h<3> permitting this. In the construction shown in Fig. 3, an initial free movement of the shock-absorber piston is permitted and the increased damping occurs only on downward movement of the vehicle wheel and is maintained only during the subsequent upward movement. The rod j in this case is adapted to be displaced by a cam-surface h<6> on the operating arm c<2> and is articulated to one end of a lever m, m<1> the other end of which bears on the cap g<5> and the fulcrum of which is formed as an eccentric rotated by a manually-controlled lever o. The position of the cam-surface h<6> determines the amount of initial free movement which together with the resistance can be varied by the lever o. The space between the conduit j<1> and the flat j<2> on the rod j forms the only locking space and communicates through hole n, conduit n<1>, and transfer passage f with the right-hand compression chamber while the opposite space communicates through hole n<2> with the liquid reservoir.