Patent GB-889937-A (GB)
Title: A vehicle suspension unit
IPC: B60G21/073
Filed: 1960-04-08
Abstract: 889,937. Pneumatic suspensions for vehicles. BOGE G.m.b.H. April 8, 1960 [April 8, 1959], No. 12692/60. Class 108(2). A pneumatic suspension transmits the forces acting on each of the two road-wheels 2 and 3 of an automobile to separate workchambers containing high pressure gas in a central suspension unit 10, said chambers housing stepped pistons 8 and 9 whose larger circular faces 13 and 14 act against the gas pressure whilst their smaller piston areas 22 and 23 act in annular chambers 15, 16 each to produce a compensating pressure which acts against the main cushioning force on the larger face of the other piston, means also being provided to return each piston to a certain position, after it has been displaced by a pivotal movement of a wheel. The main chambers 11 and 12 connect with the opposite annular chambers 16 and 15 through conduits 17 and 18. The stepped pistons are moved by bell-crank linkages 4, 5, 6 pivoted to the axles 1 (Fig. 1) or hydraulically, by movement in cylinders 56 of plungers 54 pivoted to the axles (Fig. 3). The embodiment shown in Fig. 1 has an inlet and an outlet through the wall of the cylinder 10 one or other of which is uncovered by the hollow skirt of the stepped piston when the latter is displaced (Fig. 2, not shown) and which admit or exhaust pressure from the main chamber so that the piston is returned to its neutral position. A port is provided in the piston skirt to assist in this. Fig. 4 shows in part an hydraulically operated piston in an embodiment similar to Fig. 3 wherein cushioning is provided in spherical housings 108 by air-pockets 50 separated by diaphragms 51 from the oil 52 of the main chambers 69 and 69<SP>1</SP>. The arrangement for repositioning the stepped piston in this instance comprises a perforated piston 76 sliding in an extension of the main chamber 88 and positioned between a spring 91 which also bears against the end of the chamber and another spring 81, twice as strong, which also bears against a flanged plug 80. The piston 76 carries a hollow slide-valve spindle 105 which can connect oil pressure inlet 107 or outlet 93 pipes to the main chamber 88 through a hole 86. When, due to movement of the axle 1, hydraulic pressure is exerted on the outer face 71 of the stepped piston so that it moves to the right (Fig. 4) the spring 81 bears on the piston 76 and the inlet port 107 is opened so that oil is admitted to the main chamber and returns the piston to its neutral position. An initial movement of the stepped piston in the opposite direction causes lost motion between the plug 80 and the piston 76 to permit the spring 91 to move the piston 76 and exhaust oil from the main chamber through the port 93, so that the stepped piston again returns to its neutral position. With the hydraulic constructions additional air cushion housings 110 may be provided. In an embodiment of the kind shown in Fig. 1, vibration damping may be provided by adjustable throttles in the conduits between the main and the annular chambers (Fig. 2, not shown). Height adjustment and compensation for leakage and temperature changes may be affected by known devices 61 attached to the axle 1 as at 66. Cooling fins 70 may be provided on the outside of the unit and its conduits.