Patent GB-178119-A (GB)
Title: Improvements in or relating to pressure-recuperating pneumatic apparatus
IPC: B60G17/052
Filed: 1922-04-05
Abstract: 178,119. Mercier, H. April 5, 1921, [Con vention date]. Pneumatic springs.-Relates to a pneumatic device, particularly for the suspension of vehicles but applicable for other purposes, in which air with lubricant in suspension is returned from the cylinder to the source of compressed air through a regulating outlet and again supplied to the pneumatic device so that a continuous circulation of compressed air and lubricant is produced. According to the invention, one of the two relatively movable parts of the pneumatic device is provided with a duct in throttled communication with the atmosphere and connected by a pipe to the compressor which supplies air to the device, so that oil leaking past the piston is returned to the compressor. In the vehicle suspension system shown in Fig. 1, the cylinder 3 secured to the chassis is fed with compressed air from a compressor 5 through a pipe 23, four-way valve 6, and pipe 7, the valve 6 working at such a speed that at each stroke of the compressor piston air is fed successively through the pipes 7, 8, 9, 10 to the various suspension devices, of which only one is shown. The suspension piston 2' is mounted on the axle 1. The regulating-outlet 11 is connected by a pipe 12 and valve 17 to a closed vessel 13, which communicates by similar valves and pipes to the other suspension devices and is provided with a blow-off valve 21. The com- - pressor 5 draws air from the vessel 13 and from the atmosphere through valves 24, 25 respectively and forces it through the valve 26 to the supplypipe 23. The internal walls of the cylinder 3 are formed with a spiral groove 30 leading from the atmosphere to an annular space 29 from which lubricant leaking past the packing 4 is drawn into the crank case by suction through pipes 31, 35 and a valve 27, excess oil being expelled through a valve 28 and pipe 36, from which it passes into the inlet opening 37. This arrangement provides for a continuous circulation of air and' lubricant. A modification in which the circulation is not continuous is shown in Fig. 2. The compressor 5, during the suction stroke, draws atmospheric air through a valve 43 operated by a rocker arm 44 and rod 45 actuated by a cam-shaft. The rocker 44 is carried by an arm pivoted at 47 and controlled by a piston 48. On the compression stroke, the valve 43 is closed and air, passes through the valve 42 and pipe 51 to a vessel 52 from which it passes through a pipe 62 to the pipe 61, the slide valve 58 being in such a position, when there is insufficient pressure in the suspension device, to allow the pipes 61, 62 to communicate. When the pressure in the suspension device is such that the chassis stands at the required height above the axles, the valve 58, operated by a cam 60 on the axle 1 disconnects the pipe 61 from the pipe 62 and puts it into communication with the pipe 63. The pressure in the vessel 52 and pipes 50, 51 thus increases and causes the piston 48 and arm 46 to remove the rocker 44 from the inlet valve 43 to cut off the supply of atmospheric air from the compressor. The pipe 61 then acts as a leakage outlet and conveys air and lubricant from the suspension device through pipe 63 to a vessel 55, which is provided with a blow-off valve 56 and communicates with a port 53 near the bottom of the stroke of the compressor piston. Lubricant leaking past the packing 4 is collected in an annular recess 38 and is drawn into the compressor through the pipe 40 and valve 41, the piston 3 being formed with a spiral groove 39 leading from the atmosphere to the recess 38. The invention may be applied to the suspension device described in Specification 13714/14.