Patent GB-496884-A (GB)
Title: Improvements in or relating to piston type hydraulic shock absorbers
IPC: F16F9/20
Filed: 1937-06-07
Abstract: 496,884. Hydraulic shock-absorbers ; pistons. NEWTON, N. B. June 7, 1937, No. 15683. [Class 108 (iii)] [Also in Group XXVI] In a piston-type hydraulic shock-absorber in which the piston is provided with an adjustable control valve and may rotate freely in the cylinder, and piston rods on each side of the piston extend through the closed ends of the cylinder, the piston rod is divided and one part is made rotatable relative to the other and means are provided for adjusting the valve by relative rotation of parts of the rod. As shown a piston 41, Fig. 2, is fixed to a rod 17 which extends through a guide block 15, Fig. 1, forming a closure at one end of the cylinder 10 and is rotatably connected to a piston rod 17a which extends through a diaphragm 32 forming a closure for the other end of the cylinder. The cylinder space above the diaphragm 32 forms an oil reservoir which is closed by a cap 12, Fig. 3, and the cylinder is supported in a gimbal ring 36 retained on the cylinder by nuts 37, 38. A filling cap 12a with tube 39 to form an air lock to prevent overfilling is provided in the cap 12 and the rod 17 is rotated by means inserted through the cap 12a to adjust a spring 65, Fig. 2, controlling a fluid retricting valve 63 operable on outward movement of the piston rod 17. A ring valve 50 on the piston which opens on inward movement of the piston rod has its spring tension adjusted by the rotation of a screwed ring 52 provided with a recess 53 adapted to be engaged by a plug 54 on the guide block 15, Fig. 1. When the valve is to be adjusted the piston 41 is moved to the end of the cylinder so that the plug 54 enters the recess 53, the piston is then turned to rotate the ring 52. The piston 41 is bored to receive the rod 17 which is recessed to receive a spring ring 43 which abuts a screwed sleeve 42 carrying the ring 52. A nut 44 is screwed onto the end of the piston rod to lock the rod to the piston through spring ring 43 and sleeve 42. The end of the piston rod 17 is bored to receive a piston valve 60 and spring 65 adjustable by screwed bush 66 engaged by a spigotted end 67 of the rotatable piston rod 17a. The valve 60 is provided with an orifice 63 in communication with the underside of the piston through ducts 61, 62. The piston 17a is rotatable in a cap 45 screwed into the piston 41 and is secured therein by a spring ring 58 on the rod and a nut 57 in the cap. Unintentional rotation of the rod 17a in the cap 45 is prevented by a ball catch 59. A similar ball 55 prevents rotation of ring 52. The diaphragm 32 is secured in the cylinder 10 by a spring ring 33, bevelled or rounded at one side for engagement with a nut 34 on the diaphragm. A filling valve 35 for the hydraulic cylinder is provided in the diaphragm. The guide block 15 abuts a spring ring 14 in the cylinder wall and the lower end 15a forms an abutment for a U-packing 16 seated on a washer 18 retained in position by a block 19 engaged by a ring 11 screwed into the cylinder. The block 19 is provided with packing 20. The end of the piston rod 17 is provided with a dust cover 28 secured on the rod by metal washers 25, 27, 29 and 31 spaced by rubber washers 26, 30. In a modification the piston rod 17a is rotatably held in an extension of the piston the ducts 49 covered by the valve ring 50 extending directly through the piston. In a further modification the rod 17a may screw into the piston and form the abutment means for adjusting the tension of the inner valve spring. A needle valve may replace the spring-loaded piston valve. Specification 460,851 is referred to.