Oleo/pneumatic levelling struts
AssigneeJonas Woodhead Limited
InventorWilliam Arthur Duckett
Life of this patent
Estimating the term…
Abstract
A hydro-pneumatic suspension strut for use in a self-levelling vehicle suspension system. The strut is similar in construction to a pressurized two-tube shock absorber, having a working cylinder in which a piston having damping valves is slidable, and an annular oil reservoir communicating with one end of and surrounding the working cylinder. The reservoir contains two flexible sacs, one of which contains gas for pressurizing the strut and providing suspension resilience, while the other is provided with an inlet for connection to the vehicle suspension system, so that it can be inflated to cope with increased loads.
Claims10
A levelling strut for a vehicle, comprising:
- a working cylinder;
- a piston rod which is guided concentrically with said working cylinder for axial sliding movement, with one end of said piston rod projecting from said working cylinder;
- a piston mounted on the other end of said piston rod for movement in said working cylinder;
- flow control means for permitting but controlling fluid flow between the zones of said working cylinder on either side of said piston;
- an outer cylinder which with said working cylinder defines an annular reservoir in communication with said working cylinder at least at one end of said working cylinder;
- a flexible wall isolating a portion of said annular reservoir;
- and means for connecting said isolated portion to a fluid line forming part of a ride height control system;
- the remainder of said annular reservoir and said working cylinder being filled with gas and liquid under pressure.
A vehicle including a self-levelling suspension system which comprises at least one strut arranged to transfer a load from the vehicle body to a road wheel of the vehicle, the strut comprising:
- a working cylinder;
- a piston rod which is guided concentrically with said working cylinder for axial sliding movement, with one end of said piston rod projecting from said working cylinder;
- a piston mounted on the other end of said piston rod for movement in said working cylinder;
- flow control means for permitting but controlling fluid flow between the zones of said working cylinder on either side of said piston to damp movements of said road wheel relative to said body of said vehicle;
- an outer cylinder which with said working cylinder defines an annular reservoir in communication with said working cylinder at least at one end of said working cylinder;
- and a flexible wall isolating a portion of said annular reservoir;
- the remainder of said annular reservoir and said working cylinder being filled with gas and liquid under pressure;
- and said suspension system further comprising a source of fluid pressure, and valve means arranged to control fluid flow from said source to said isolated portion and from said isolated portion to a region of lower pressure in dependence on the position of said road wheel relative to said body of said vehicle, to tend to maintain said road wheel in a predetermined position relative to said body.
Dependencies are inferred from the claim text.