GB1210712A - Improvements relating to methods and apparatus for controlling vehicle suspensions - Google Patents

Abstract

1,210,712. Adjusting suspension heights. DAIMLER-BENZ A.G. 3 April, 1968, No. 15997/68. Heading B7D. [Also in Division H4] A method of controlling a vehicle suspension in dependence on the nature of the running surface comprises determining the deviation of that surface from a plane by means of a measuring beam of radio, ultrasonic, &c. waves so that a corresponding electric pulse is produced which is fed to a control means which adjusts the suspension according to the deviation. A single measuring beam is used, and all the wheels or axles of the vehicle are centrally controlled by the same pulse. In an apparatus for the purpose, the measuring beam is tilted forwards as the speed of the vehicle increases. For example, a measuring head 17, Fig. 2, which is mounted on the front cover 16 of an axle gear-box casing 15 of a driven axle, is swivelled by a centrifugal governor 18 driven by the crown wheel 19 of the differential. When the measuring head is mounted on the sprung part of the vehicle, correction means may be provided, so that the measuring beam intersects the running surface at substantially the same distance ahead at any particular speed, in spite of vertical movement of the measuring head. As described, a measuring head is disposed beneath the driver's cab, at a distance a in front of the wheel centres 20, Fig. 3, and is provided with an upwardly pointing lever 21, having a slot 22. By means of a pin 23 the piston-rod 24 of an adjusting piston 25, which is disposed in a cylinder 26, engages in said slot. The cylinder 26 lies parallel to the running surface and the piston 25 is adapted to be moved in it against a spring 27 by oil from a pipe 28 at a pressure adjusted by a control device 29 to be proportional to the speed of travel of the vehicle. At minimum speed the beam 14 from the measuring head points downwards, and as the speed rises and the head swivels it points more and more ahead. Signals from the head are transmitted through cables 31 to an electronic transducer 32, which produces a corresponding pulse, by which the vehicle suspension 34 is controlled by means of a control device 33. The cylinder 26 is movable transversely by two pistons 35, which are disposed in cylinders 36 mounted fast on the frame or other fixed part of the vehicle. The pistons 35 are movable against springs 37 by oil from a pipe 38 at a pressure adjusted by a control device 39 in dependence on the level height of the vehicle. If the vehicle frame is raised to a higher level in relation to the wheels, the pressure in the pipe 38 rises; and the pistons 35 pull the adjusting cylinder 27 a further distance upwards in relation to the measuring head, i.e., the distance c increases to a distance d. The consequently increased distance of the pin 23 from the pivot of the measuring head reduces the angular movement of the latter by the piston 25, and at a particular speed the beam remains pointing at substantially the same relative distance ahead. The measuring head mounting may be linked with the steering of the vehicle so that the beam points along the intended path of the vehicle, instead of straight ahead, and the apparatus may be rendered ineffective at low speeds.