A fluid-driven linear motor comprises a cylinder, a piston, and a piston rod connected to the piston. Two sides of the piston in the cylinder are alternately supplied with fluid from a slide valve arrangement. The slide valve arrangement includes a slide and a pilot rod adapted to alternately set a through-bore of a slide in fluid connection with the ends of the slide when the piston is located in its end positions. The pilot rod is provided with an extension rod adapted to move inside a bore of the piston and the piston rod, so that the stroke length of the linear motor can be extended. A pressure chamber is provided at the distal end of the pilot rod. The pressure chamber is adapted to hold the pilot rod with a holding force when in its end positions until mechanical forces from the piston overcome said holding force.

Hydraulic cylinders and methods of fabricating hydraulic cylinders, including long-stroke rolling diaphragm cylinders with any stroke length. In some embodiments, the cylinders are manufactured to have a stroke length to bore diameter (“stroke-to-bore”) ratio optionally greater than 1:1. Various embodiments are suitable for use in a passive hydraulic body-powered wearable robot, for example.

An apparatus for converting rotation to fluid flow, comprising a fluid conduit coiled around a rotational axis, the fluid conduit having a first inlet for receiving first fluid having a first density and a second inlet for receiving second fluid having a second density, and a first outlet for output of first fluid and a second outlet for output of second fluid; a motor coupled to the fluid conduit to rotate the fluid conduit around the rotational axis in a first angular direction such that first fluid portions of first fluid and second fluid portions of second fluid are transported along the fluid conduit towards the first outlet, while being pressurized; and a fluid returning arrangement, fluid flow connecting the second outlet and the second inlet for selectively allowing pressurized second fluid to return from the second outlet to the second inlet, while depressurizing the pressurized second fluid.

An apparatus for converting rotation to fluid flow, comprising a fluid conduit coiled around a rotational axis, the fluid conduit having a first inlet for receiving first fluid having a first density and a second inlet for receiving second fluid having a second density, and a first outlet for output of first fluid and a second outlet for output of second fluid; a motor coupled to the fluid conduit to rotate the fluid conduit around the rotational axis in a first angular direction such that first fluid portions of first fluid and second fluid portions of second fluid are transported along the fluid conduit towards the first outlet, while being pressurized; and a fluid returning arrangement, fluid flow connecting the second outlet and the second inlet for selectively allowing pressurized second fluid to return from the second outlet to the second inlet, while depressurizing the pressurized second fluid.

A bladeless wind turbine that creates electrical energy using hydraulically connected pistons. The system may include a disk, a small piston in fluid communication with a large piston, and a crankshaft attached to the large piston. The disk transfers forces from the wind to the small piston. Hydraulic fluid then transfers the forces to the larger piston. When the disk and associated small piston have been forced to the end of their stroke by the wind, a gate in the disk is opened to reduce wind force on the disk by allowing air to travel through the disk. Consequently, the disk and associated small piston are pushed back to the beginning of the stroke by the pressure created by the large piston's weight. This process is repeated by closing the gate in the disk. A crankshaft powering an electric generator is turned by the movement of the large piston.

Hydraulic cylinders and methods of fabricating hydraulic cylinders, including long-stroke rolling diaphragm cylinders with any stroke length. In some embodiments, the cylinders are manufactured to have a stroke length to bore diameter (stroke-to-bore) ratio optionally greater than 1:1. Various embodiments are suitable for use in a passive hydraulic body-powered wearable robot, for example.

A measurement of the pressure of hydraulic fluid in a fluid working machine can be determined from the timing of the movement of valves which selectively seal a working chamber of cyclically varying volume from a fluid gallery. The timing of opening of a low pressure valve, to connect a working chamber to a low pressure fluid gallery, following the closure of a high pressure valve to seal a working chamber can be used to estimate the pressure in the high pressure fluid gallery at the moment of closure of the high pressure valve.