Patent GB-191507850-A (GB)
Title: Improvements in and connected with Antivibration Devices for Automobiles and like Vehicles.
Inventor: BELL GEORGE WILLIAM
IPC: B60G11/26
Filed: 1915-05-27
Abstract: 7850. Bell, G. W. May 27. Pneumatic springs; dash-pots.-Relates to pneumatic suspension devices for automobiles and like vehicles of the piston-and-cylinder type, and particularly to the type described in Specification 21,700/13 and which are disposed between the wheel and the axle and within the wheel hub. The main objects of the invention are to provide automatic means to maintain the piston air-tight in the cylinder, and to lubricate the same. Oil is supplied to the lower chamber 3<a>, Figs. 1 and 2, of the cylinder 3, to a depth to insure the complete immersion of the piston packing, by a conduit leading from the counterbored front face 1<e> of the piston 1, to which access may be obtained when the cap 16 is removed from the wheel 8. The piston 1 is provided with two packing-rings 11, 12, Figs. 1, 2, and 8, separated by a groove 11<c> leading to an annular chamber 11<b> formed in the piston or in the metallic rings 11<a>, 12<a> used to secure the packing-rings 11, 12 in position. Any oil which passes the packing-ring 12 is thus trapped in the chamber 11<b>. Air under pressure is automatically supplied to the device from time to time, to replace leakage or to enable the device to carry an increased load, through a conduit 9 communicating through a packing-gland 9<a> in the rear counterbored face of the piston, with a vertical conduit 9<b> leading to the annular chamber 11<b> in the piston; the air then passes through a valve 12<b> in the lower face of the chamber 11<b> and bubbles through the oil in the chamber 3<a>, the oil which has accumulated in the chamber 11<b> simultaneously passing back in to the chamber 3<a>. To permit air to escape when necessary, for example to accommodate a lighter load, a conduit 17<a> leads from the upper chamber 1<a> of the piston, through a packing-gland 17<c>, to a conduit 17. To prevent the oil from entering the enlargements 3<b>, Fig. 2, of the air chambers 1<a> of the piston, a tube 13<a> on the piston, communicating by a passage 1<c> with the upper chamber 1<a>, telescopes within a tube 13<6> on the cylinder 3. The bottom of the tube 13<b> is enlarged to form a ferrule 13, which acts in conjunction with the lower end 1<d> of the piston to form a dash-pot when the piston descends. To conserve the oil in the dash-pot formed between the upper end of the piston and the cylinder 3, the vent holes 10, Fig. 2, communicate with an oil reservoir 10<a>, oil being supplied when necessary through a conduit leading from the front counterbored face 1<e> of the piston to the upper face of the boss 1<f>. In a modification, a single conduit is used to convey air to and from the device. The piston 1, Fig. 7, is provided with h a tube 20 joining the air-inlet conduit 9<b> and the outlet conduit 17<a>, and fitted with a check valve 21. The valve 21, which is normally held closed by a spring 21a, is formed at its upper end with a piston 21<b> fitting air-tight in the tube 20 and containing a valve 24. In action, when air under pressure is admitted to the conduit 9<c>, the valve 21 is lifted, and air passes through the valve opening 23; when the air outlet valve is opened, the pressure of the air in the device opens the valve 24, and air escapes through the passages 27<c> and conduit 9<c>.