GB929952A - Improvements in or relating to hydro-pneumatic suspension devices - Google Patents

Abstract

929,952. Road vehicle suspensions; hydraulic shock absorbers. ARMSTRONG PATENTS CO. Ltd. June 30, 1961 [July 27, 1960], No. 26047/60. Classes 108(2) and 108(3). A hydropneumatic suspension device which maintains a vehicle at a constant height and acts as a shock absorber comprises a body member 10 connected to the vehicle body and in which is rotatably mounted a spindle 26 attached at its outer end to a lever or other member connected to the vehicle wheel mounting, a crank 28 integral with the spindle 26 being pivotally connected to a connecting rod 32 which bears against a bearing pad 31 in a piston 30 slidably contained within a cylinder 18 inclinedly mounted in the body 10. A cap member 14 is mounted on the body 10 and within which an air chamber 22 is defined by a diaphragm 20. The chambers 12 and 24 on either side of piston 30 contain hydraulic fluid and these chambers are connected by passageways 36 and 64, the former containing a non- return valve 54 and a pump spindle 38 connected at one end to a spigot 44 eccentrically mounted on spindle 26 and having a ball valve 50 controlling a passageway 46 extending through the spindle, and the latter containing a non- return valve 66 which may be unseated by a plunger 72 co-acting with a cam surface 62 formed on spindle 26. The cylinder 18 is closed by an apertured member 74 against which a plate 82 is spring urged, calibrated apertures in plate 82 registering with the apertures in member 74. In a cover member 86, by which the device is attached to the vehicle body by bolts 94 passing through its flanges 92, an air chamber 90 is defined by a diaphragm 88 bounding the chamber 12. In the action of the device, load applied to the vehicle body rotates the spindle 26 clockwise as seen in Fig. 1 and the piston 30 is moved to the right, compressing the air in chamber 22. As road shocks occur in transit, the reciprocating motion of spindle 26 causes a pumping action of pump 38 whereby liquid is transferred from chamber 12 to chamber 24 and the piston 30 is moved to the left as viewed in Fig. 1. At a given position, corresponding to the vehicle riding height, the cam 62 causes the plunger 72 to trip valve 66 so that a constant riding height is maintained. The apertures in plates 74 and 82 tend to dampen shocks, and sudden, heavy shocks will tend to cause the plate 82 to move away from plate 74 against the action of its retaining spring. In a modification, Fig. 7, the piston 130 is made integral with the connecting rod 132 upon which is mounted a thrust pad 133 bearing against a roller 135 carried by the crank 28. In this embodiment, a member 140 within the cap member 86, Fig. 6, additionally supports the spindle 26 through needle rollers 142. An alternative shock absorption member applicable to both embodiments comprises a plate 174, Fig. 7a, having small apertures 175 and large apertures 176 closed by a plate 180 acted upon by a spring 184 bearing on a flanged bush 178 which is also provided with apertures 182 and 189, the aperture 182 being closed by a valve member 183 spring urged against its seat and slidable on a spigot member 187. This device caters for shocks in the bump direction, the plate 180 being forced away from its seating to allow the passage of fluid, and also in the rebound direction when the valve 183 will be unseated. The apertures 175 allow re-centering of piston 30(130).