Patent GB-1036227-A (GB)
Title: Motor vehicles having pressure fluid-operable suspension systems
IPC: B60G17/04
Filed: 1964-09-17
Abstract: 1,036,227. Diaphragm compressors. GENERAL MOTORS CORPORATION. Sept. 17, 1964 [Nov. 29, 1963(3)], No. 37989/64. Heading FIN. [Also in Division B7] A motor vehicle suspension includes an air spring-vibration damper unit which comprises an hydraulic vibration damper surrounded by an air cushion supplied with air under pressure under the control of a valve from a reservoir which is common to the several wheel units and is supplied with air by a pump mounted on one end thereof and comprising two housings 44 and 46 between which is held a diaphragm 78 having reinforcing elements 82 and 80. The spaces 74 and 76 on either side of the diaphragm are connected to apertures 127 and 128 in a valve plate 60, Fig. 7, in which is also formed an aperture 126 connected to the induction manifold of the vehicle engine. A valve element 134 is pivotable on the plate 60 about a pin 136 and has a recess 139 large enough to cover two of the apertures 126, 127, 128. The element 134 is rocked by a piston 88 connected to the diaphragm 78 through a crank 146 bent arm 150, radius arm 140 and lever 168 which has a pin 178 depending into a slot 182 formed in the member 134, a spring 174 being provided to give a snap action. When the member 134 covers the apertures 126 and 127, so connecting one side of the diaphragm to the low pressure of the engine manifold, the other side is connected to atmosphere through the aperture 128, causing movement of the diaphragm and of the piston 88 until at the end of the stroke, by a snap action of the valve member 134, the opposite set of conditions is brought about. During reciprocations of the piston 88, air passes through the passage 112 past a one way valve 114, along an axial passage 119 and past one way valves 116 and 120 into the reservoir 34. Air from the reservoir 34 is admitted to the wheel units through a passage 50 under the control of a valve 52, shown in detail in Fig. 10 and comprising an inlet passage 214 and outlet 54 controlled by a spring-loaded non-return valve 252 which may be tripped by a stem 256. A space 218 is at the pressure of the air in the wheel units and is bounded by a flexible diaphragm 222 which is connected to a piston member 224 in which is located a spring-loaded non-return valve 250 having an extension for engagement with the tripping stem 256 and its own tripping stem 246. The piston member 224 rests upon a sliding member 234 acted upon by a compression spring 239 and having rack faces 235 engaged by a pinion 286 on a shaft 278 upon which is mounted a lever 276, Fig. 9. A spring 272 is connected between studs 274 and 270 mounted on levers 276 and 262 respectively, the latter being pivoted for rotation about a stud 269. In a mid-position, the lever 276 is upright and the air pressure in the space 218 is balanced by the spring 239. When deviating from this position due to diminution of pressure in the space 218, the spring 239 causes the rack member 234 and piston 224 to move upwardly and trip the stem 256 whereby pressure air is admitted to restore the elements at their mid-position of equilibrium. The riding pressure of the air in the suspension elements can be varied by rotating the lever 262 by means of a Bowden cable 58. If the lever 262 is rotated in an anticlockwise direction, the spring 272 rotates the lever 276 in a clockwise direction and a new position of equilibrium is found wherein the springs 272 and 239 act in series, whereas by rotating the lever 262 in the clockwise direction, a position of equilibrium is found with the springs 272 and 239 acting against one another. By advancing the lever to a limit position in the latter direction, the air pressure in the suspension elements can be brought to a minimum. Movement of the pinion 286 is damped by means of a friction disc 297 acting between surfaces on the body casing 284 and a cover member 296. A limited amount of play is allowed between a driving element 290 fixed to the shaft 278 and the friction disc, equal to the throw of the valve stem 256. With movements of the piston in a downward direction the limiting position is reached wherein the valve stem 246 is tripped by an actuating member 244 and the air from the suspension units escapes via a passage 253.