GB565630A - Improvements in or relating to liquid damped shock absorbers - Google Patents

Abstract

565,630. Hydraulic shock-absorbers. RIBBESFORD CO., Ltd., and THORNHILL, P. W. Jan. 8, 1943, No. 423. [Class 108 (iii)] [Also in Group XXI] Relates to a hydraulic shockabsorber of the piston - and - cylinder type particularly for a gun-carriage suspension, in which damping means in the piston 24 affords restricted communication between the working spaces 26, 27 on each side of the piston and a floating piston 44 slidably mounted in the cylinder, forms a boundary wall for one of the spaces to compensate for the variable displacement of the pistonrod 19. According to the invention, the damping means is adjustable from the exterior of the shock-absorber by a member extending longitudinally through the piston-rod 19 and having operating means accessible from the outside of the shockabsorber. As shown, the shock-absorber operates, in conjunction with a helical spring 10, between brackets 11, 12 secured respectively to a vehicle frame or body and a wheel-axle or equivalent. Flow of liquid between the spaces 26, 27 through passages 29 in the piston 24, is controlled by a byepass valve 33 contained in a recess 28 in the piston and normally pressed by a spring 35 against a flange 32 on a seating member 30 screwed into the piston, a passage 37 through the valve being constricted by a pin 38 secured to the end of a rod 39 which is adjustable axially in the piston-rod 19 by means of an end nut 41. The floating piston 44, comprising a rubber washer clamped between metal plates 46, 47, is urged downwards by a spring 51 consisting of dished washers 52 which bear against a cap 17 closing the upper end of the cylinder 13. Normal relative movements of the brackets 11, 12 are checked by the restriction to flow of liquid offered by the constricted passage 37; heavy shocks tending to compress the shock-absorber cause the valve 33 to lift from its seat, liquid thus passing between the face 34 of the valve and the flange 32 ; while heavy shocks tending to extend the shock-absorber cause the liquid in space 26 to force the floating piston 44 upwardly. The device may be locked to prevent relative movement of the brackets, particularly when applied to a gun-carriage and the gun is in action, by screwing the nut 41 to force the rod 39 downwards until its lower end abuts the upper face of the valve 33, completely closing the passage 37 and forcing the valve into engagement with the flange 32. By completely withdrawing the rod 39, the shock-absrober may be filled with liquid. The floating piston may be in the form of a disc disposed at the end of the cylinder opposite the piston-rod, the byepass valve then being modified to open in the opposite direction against spring action when the shock-absorber is suddenly extended.