Patent GB-1362303-A (GB)
Title: Pneumatic devices for correcting the trim of a motor vehicle
IPC: B60G17/015
Filed: 1972-03-01
Abstract: 1362303 Suspension levelling systems REGIE NATIONALE DES USINES RENAULT and AUTOMOBILES PEUGEOT 1 March 1972 [4 March 1971 8 Feb 1972] 9648/72 Heading B7D [Also in Division F1] In a closed-circuit pneumatic levelling system for a vehicle suspension comprising an air pressure reservoir 1, pneumatic actuators for controlling the suspension level, and a singleacting compressor 6 disposed in the reservoir 1, operation of the motor 39 (Fig. 8) of the compressor by a height sensing switch 29 through time delay means 30 and a two-position pressuresensitive switch 27 responsive to the reservoir pressure, the height sensing switch 29 also controlling operation of a pair of three-way solenoid valves 50, 51 each communicating through one line 42a, 42b with the inlet 11 to the compressor 6, through a second line 31a, 31b with the compressor outlet 10, and through a third line 44a, 44b with the reservoir 1 in the case of one valve 50 and with the pneumatic actuators 2 in the case of the other valve 51. When the reservoir pressure is above a predetermined value the pressure-responsive switch 27 assumes a position wherein the appropriate one of the solenoid valves 50, 51 is operated simultaneously with the compressor 6 as dictated by the height sensitive switch 29, whereas if the reservoir pressure is low the switch 27 assumes a second position wherein the compressor operates alone to introduce into the reservoir atmospheric air drawn in through a non-return valve 25. A pressure-responsive switch 26 prevents excessive pressures in the pneumatic actuators 2 and a relief valve 62 limits the reservoir pressure to a predetermined maximum. Each solenoid valve 50, 51 comprises as shown in Fig. 4 a solenoid winding 47 housed in a case 45 attached to a base 40 formed with passages 42, 44. A ball valve 41 for closing the passage 42 is loaded by a spring 46 bearing against a valve member 38 for closing an axial passage 31 in a core 34 disposed centrally of the winding 47 and having at its lower end truncated fins 48 forming a frustoconical base engaging the ball valve 41. When the winding 47 is not energized the ball valve 41 closes the passage 42 and the valve member 38 is openable against the resistance of the spring 46 by air delivered to the passage 31 from the compressor 6. When the winding 47 is energized the ball valve 41 is lifted to open the passage 42 and compression of the spring 46 prevents opening of the valve member 38. The compressor 6 comprises as shown in Fig. 3 a main diaphragm 7 connected to a piston 8, 9 reciprocated by an eccentric 13 on a rotating shaft 14, and a valve diaphragm 18 having a central aperture 22. When the piston 8, 9 is descending the valve diaphragm 18 uncovers an annular passage 21 so that air from an inlet 16 can enter chamber 20 through the aperture 22. When the piston 8, 9 is ascending a portion of the valve diaphragm 18 located in an annular groove 24 is lifted from passages 23 so that air can flow from the chamber 20 to an outlet 17 through the passages 23 and orifices formed in diaphragm 18 in the area of the groove 24 but not coinciding with the passages 23.