Patent GB-976810-A (GB)
Title: A fluid operated suspension device for a vehicle
IPC: B60G17/033
Filed: 1962-03-09
Abstract: 976,810. Fluid-operated suspension units. A. A. L. CHANEAC, and H. G. CHANEAC. March 9, 1962 [March 10, 1961], No. 9173/62. Heading F2S. [Also in Division B7] A suspension device for a vehicle travelling on at least two wheels comprises a cylinder secured to the vehicle between two of its wheels, at least two pistons being fitted in the cylinder, each piston being connected to one of the wheels so as to move in the cylinder in response to load changes on the wheels, the pistons subdividing the cylinder into at least one intermediate compression chamber and two extreme compression chambers, and fluid transfer means responsive to the movement of the pistons in the cylinder for transferring pressure-exerting fluid between the intermediate and both extreme compression chambers to counteract the load changes on the wheels. As shown in Fig. 1, the hydro-pneumatic suspension unit comprises a cylinder 1 secured to the vehicle body and having pistons 2 and 3 connected by rods 5 and 6 and linkwork to a pair of wheel mountings, which may be wheels on opposite sides or the same side of the vehicle or a front wheel on one side and a rear wheel on the other, the linkwork being such that when the associated wheel is raised, e.g. by passing over a bump, the piston moves outwardly in the cylinder. Pressure fluid from an engine-operated pump is admitted through a duct 13 and pressure gauge and adjustment valve 14 to the central chamber 7 to initially move the pistons outwardly. The central chamber 7 and end chambers 8 and 9 communicate with flexible chambers 10, 11 and 12, located in fluid tight chambers 10, 11 and 12 providing air springs. The pistons are provided with passages 2 1 , 2 2  and 3 1 , 3 2  respectively and the cylinder 1 is provided with passages 18 and 19 and ducts 16 and 17 lead to the reservoir. When the engine is first started, the pistons are moved outwardly to a riding position and thereafter, road vibrations are compensated for by passage of fluid from the central chamber to the end chamber via the passages 2 1 , 3 1  and 18, 19 or from the end chambers to reservoir via the passages 2 2 , 3 2  and 16, 17. A stop-cock 15 may be provided to enable one wheel to be raised. In a modification, Fig. 2, a cylinder 1 comprising pistons 2 and 3 has pressure fluid supply lines 13, which divides into the lines 13 1  and 13 2 , and 20, dividing into the lines 20, and 20 2 , and exhaust lines 16 and 17. A single passage 2 1  and 3 1  is provided in each piston and the central space 7 is divided by a movable piston 21 acted upon by springs 22 and 23 anchored to the piston. In Fig. 3, the central chamber 7 of cylinder 1 is supplied with fluid through a duct 13 and the pistons 2, 3 have passages 2 3  and 3 3  respectively communicating with the end chambers 8 and 9 and controlled by valves 24 1  and 24 2  tripped by fingers 25 1  and 25 2  attached to the cylinder or to the pistons. Discharge passages 16 and 17 from the chambers 8 and 9 are controlled by valves 24 3  and 24 4  which are tripped by fingers 5 1  and 6 1  attached to the connecting rods 5 and 6, or by a level corrector connected to the vehicle suspension arms. As shown in Fig. 4, a pressure fluid supply line 13 to the cylinder 1 has two branches 13 1  and 13 2  and a three-part passage 26 is provided. In one-outer-position of the pistons 2, 3 pressure fluid is supplied to the end chambers 8 and 9 through the piston passages 2 1  and 3 1  and in an inner position, the end chambers 8 and 9 communicate with the central chamber 7 through the passages 2 1  and 3 1  and 26. Flexible chambers 10, 11, 12 and 13 are provided in fluid-tight chambers 10, 11, 12 and 13 and the central chamber 7 has an outlet passage 27 controlled by a calibrated valve 27 1 . As shown in Fig. 5, the cylinder 1 has a fluid supply pipe 13 branching into the pipes 13 1  and 13 2  and supply pipe 20 having a pressure gauge and expansion valve 14 and stop-cock 15, the pistons 2, 3 having passages 2 1 , 2 2  and 3 1  3 2  respectively which register with the inlet ports 13 1 , 13 2  and outlet pipes 16, 17 at different positions of the pistons. In Fig. 6, the pistons 2, 3 have no passages, the cylinder having a central fluid supply 20, branch supply lines from the supply line 13 controlled by valves 28 1  and 28 2  and exit lines 34 and 35 controlled by valves 24 3  and 24 4 , the valves being tripped by fingers 25 3 , 25 4  and 5 1 , 6 1  upon the pistons and connecting rods respectively. In Fig. 7, air is supplied through tube 20 and branch tubes 13 1  and 13 2  which may comprise check valves 37 and the pistons 2, 3 comprise passages 2 3  and 3 3  controlled by valves 24 and 24 2 , check valves 37 also being provided. The central space 7 is evacuated through a passage 30 through piston 2 and the centre of connecting rod 5 under the control of valve 31 whose stem 32 is retained in the opposite piston 3. Fig. 8 is a modification of the devices shown in Figs. 5 and 6 comprising fluid inlet passages controlled by valves 28 1  and 28 2  tripped by fingers 25 3  and 25 4  on the pistons 2 and 3, and ducts 34 and 35, controlled by valves 24 3  and 24 4 , lead to exhaust, there being also passages 2 2  and 2 3  in the pistons 2 and 3 which register with the exhaust passages 16 and 17 at certain positions of the pistons.