GB596477A - Improvements in or relating to recoil dampers for vehicle suspensions - Google Patents

Abstract

596,477. Hydraulic shock dampers. COWEY, L. E. July 26, 1945, No. 19221. [Class 108 (iii)] Relates to a hydraulic recoil damper for vehicle suspensions of the type comprising a piston 5 slidable in an inner liquid-filled cylinder 2 and connected to an outer concentric cylinder 1 by a rod 3 slidable in a guide 4 on the inner cylinder, ports 7 in the piston being controlled by valve means 6 so that little resistance is offered to compression of the damper, while the piston is also provided with means which check extension or recoil. According to the invention, remotelycontrollable means are provided for varying the response of the checking means. As shown in Fig. 1, the checking means consists of further piston ports 52 controlled by a valve 50 loaded by a spring 53 the resistance of which is variable hydraulically by forcing liquid from a remote manually-operable cylinder and plunger device through a bore in the piston-rod 3 and radial holes 58 to a cup 55 secured to the piston-rod, the liquid forcing upwards an abutment 54 on which the lower end of the valve spring 53 rests. The outer cylinder 1 slides on the outer of a pair of cylinders 2, 15 and the annular space 20 between the cylinders 2, 15 is connected by a passage 4e with a substantial annular space 20a in the piston-rod guide 4 and acts both as a reservoir for liquid displaced by the piston and as a recuperator to return liquid to the cylinder 2 through holes 25 in the cap 16. The return of liquid escaping along the pistonrod beyond the inner cylinder to the annular space 20 through apertures 24 is assisted by the compression of air in the top of the cylinder 1. The damper is mounted in position by means of a bracket secured to the cap 16 and by a resilient gimbal form of connection between a ring 26 on the cylinder 1 and a supporting bracket. To prevent damage to the damper if pressure is applied when the contained liquid is frozen, a shear ring 21 forming a key between a grooved part 22 of the upper end of the pistonrod 3 and a cap 8 closing the upper end of the cylinder 1, acts as a safety device by allowing the cylinder 15 with the rod 3 to slide relatively to the cylinder 1. The cylinder 2 is charged with liquid through a valve-controlled bore 33 in an extension of the cap 16, and the rubbing surfaces of the cylinder 1, 15 are lubricated by oil percolating through a felt ring 24a and the apertures 24 in the cupped top of the guide 4. The remote control device comprises a plunger 63, Fig. 3, slidable in an extension 64 of a cylinder 65 under the action of a traversing screw 67 rotatably mounted in the free end of the extension 64, the cylinder 65 having radial outlets 66 for connection to the damper, or several dampers, and to a gauge.