Patent GB-542142-A (GB)
Title: Improvements in or relating to shock absorbers
IPC: F16F9/088
Filed: 1940-06-24
Abstract: 542,142. Shock absorbers. AUTOMOTIVE PRODUCTS CO., Ltd., and THORNHILL, P. W. June 24, 1940, Nos. 10809/40, 4697/41 and 8884/41. [Class 108 (iii)] In a shock absorber of the kind having a variable volume working space filled with liquid in communication through a valve with a chamber containing resilient pressure devices, the valve is controlled by the pressure in a container to which pressure fluid from the absorber passes by way of a constricted passage so that the pressure in the container corresponds to the static load on the absorber. The apparatus shown in Fig. 1 comprises a piston cylinder 15 working in a cylinder 10 with a communicating passage in the piston head controlled by a valve 45. A rubber bag 69 extends within the cylinder 15 between a support 73 and the piston head and is charged with air under pressure through a valve 35, a nipple 75 and passages 77, 79 in a screw-plug 78 and the member 73 respectively. A tube 74 extending between the member 73 and the bore 66 of the piston head communicates through a porous plug 80 with the interior of the leg, so that the pressure in the tube is slowly brought to the static head pressure of the absorber. A piston 43 on the upper end of the valve spindle works in the bore 66. When the pressure in the absorber is raised or lowered by shock the valve is moved by the difference of pressures within the chamber 10 and the tube 74. The valve 45 moves between annular seating members 50, 51, Fig. 2, yieldingly held against an abutment ring 52 by springs 53, 54 as described in Specification 533,048. The piston head is provided with a rubber ring 37 which serves as a non-return valve for passive liquid leaking around the piston head back into the cylinder 10, as described in Specification 531,099. In one modification a piston is used instead of a rubber bag to separate the air and liquid in the cylinder 15. In another modification the piston 43 is a loose fit in the bore 66 so that liquid can.leak slowly into the tube 74 from the cylinder 10 and the tube 74 may be closed at the top. As shown in Fig. 7, the piston cylinder 15 is formed with a triangular groove 91, containing packing, &c. corresponding inward projection with which a valve plate 99 co-operates. The plate is normally held in position to close the passage through the projection by spiders 100, 101 under the influence of springs 102, 103 engaging collars 104, 105 on a rod 106. The bag 69 contains air under pressure which can leak past a piston 107, fixed to the rod 106, to the space 110. Fig. 11 shows a modification in which the pressure fluid in the cylinder 15 is in communication through a tube 116 with the lower surface of the piston 107, past which it can leak. The space above the piston 107 is fitted with an auxiliary piston 117 under pressure of a spring 119. The plate 99 can be replaced by a cylindrical block 127, Fig. 12 with grooves 129 cut in its upper and lower edges. Movement of the block is limited by collars 125, 128 on the rod 106 and movement of the rod is limited by the engagement of collars 124, 125 with a stop 126 carried by the cylinder 15.