Abstract: An adjustable magneto-rheological fluid device includes a movable piston adjacent a first chamber containing a first hydraulic fluid for moving the piston. The first hydraulic fluid interacts with a flexible magneto-rheological compartment containing a magneto-rheological fluid that flows between a first magneto-rheological fluid chamber and a second magneto-rheological fluid chamber. By controlling the flow of the magneto-rheological fluid, the device controls the first hydraulic fluid in the first chamber to bias the piston in a first direction. Additionally, the magneto-rheological fluid device may include a second chamber, containing a second hydraulic fluid, spaced apart from the first chamber on the opposite side of the piston. The second hydraulic fluid interacts with the flexible magneto-rheological compartment allowing the device to control the second hydraulic fluid to bias the piston in a second direction opposite the first direction.

Abstract: A rest portion is used to support a load at an adjustable height relative to a base which is connected to the rest portion by a pivotal linkage. A hydraulic ram coupled to a gas spring cylinder applies a spring force between the linkage and the base, the geometry of the linkage and ram being such that the upward component of spring force is invariant with respect to height adjustment. A control valve allows the ram to be locked at a selected height and the spring force provided by the gas spring is adjustable by movement of a second piston within the gas spring cylinder to vary the available volume of gas. A hydraulic pump is used to supply hydraulic fluid to the cylinder for adjusting movement of the second cylinder. The apparatus is suited for use in a chair-bed enabling a patient to be supported at an adjustable height during medical treatment.

Abstract: An hydraulic liquid system wherein a pump moves liquid from one location to another such as in supplying one or more loads in an underwater environment. The system includes two hydro-pneumatic chambers utilized such that one is filled by liquid from the pump while the other supplies the load, and as one hydro-pneumatic chamber empties, valves reconfigure the system such that the hydro-pneumatic chamber reverse roles. Each hydro-pneumatic chamber includes a liquid side and a gas side separated by a movable barrier with the gas sides of the hydro-pneumatic chambers being connected to one another thereby providing a large acoustic transmission drop across a liquid-gas boundary and subsequent gas-liquid boundary to interrupt the liquid noise path from the pump to the load.