A valve assembly for regulating the flow of working fluid between a working chamber of a fluid working machine and a working fluid gallery comprises: a valve comprising a valve member and one or more cooperating valve seats; an actuator actuatable to apply a force to urge the valve member away from or towards the one or more valve seats; and a coupling between the actuator and the valve member. The coupling comprises a connector located at least partially within a tube. A connector void provided between at least a portion of the connector and the tube is in fluid communication with a working fluid gallery outlet.

A plurality of guide shafts which are disposed parallel to an input/output shaft (a first input/output shaft, a second input/output shaft) are assembled in a case body which holds a cylinder in which first and second piston sets, move reciprocally. A first guide bearing, which abuts both side surfaces of a first piston body and receives only lateral pressure generated by the reciprocal movement, and a second guide bearing, which abuts both side surfaces of a second piston body and receives only lateral pressure generated by the reciprocal movement, are assembled coaxially and separated in an axial direction on each guide shaft.

A hydraulic system is provided for powering one or more external hydraulically powered devices. The system includes one or more pumping systems attached to a common crankshaft and including an inner sleeve, an outer sleeve, a valve member and an end body. The system can include a pair of high pressure fluid tanks and a low pressure fluid tank. The pumping systems can increase the fluid pressure within the high pressure fluid tanks back and forth and in a sequenced manner, and force the higher pressure fluid through the one or more powered devices. Drive systems are provided to assist the pumping systems in rotating the common crankshaft. The drive systems can include a piston assembly for rotating the crankshaft and a valving system for directing fluid into the piston assembly to power the piston assembly.

A prime mover and a plurality of hydraulic actuators, a hydraulic machine having a rotatable shaft in driven engagement with the prime mover and comprising a plurality of working chambers, a hydraulic circuit extending between working chambers of the hydraulic machine and the hydraulic actuators, each working chamber of the hydraulic machine comprising a low-pressure valve which regulates the flow of hydraulic fluid between the working chamber and a low-pressure manifold and a high-pressure valve which regulates the flow of hydraulic fluid between the working chamber and a high-pressure manifold. The hydraulic machine being configured to actively control at least the low-pressure valves of the working chambers to select the net displacement of hydraulic fluid by each working chamber on each cycle of working chamber volume, and thereby the net displacement of hydraulic fluid by the working chambers, responsive to a demand signal.

Methods, systems, and techniques for harnessing wind energy use a tethered airfoil and a digital hydraulic pump and motor, which may optionally be a combined pump/motor. During a traction phase, a wind powered airfoil is allowed to extend a tether and a portion of the wind energy harnessed through extension of the tether is stored prior to distributing the wind energy to an electrical service. During a retraction phase, the wind energy that is stored during the traction phase is used to retract the tether. The digital hydraulic pump and motor are mechanically coupled to the tether.

The hydraulic apparatus is set so that the ratio of the pressure-receiving area of the respective bottom oil chambers of the boom cylinder, the arm cylinder and the bucket cylinder to the pressure-receiving area of the respective rod oil chambers matches the ratio of the extruded volume drawn into or discharged from the bottom oil chambers per single rotation by the respective extrusion members of the first hydraulic pump motor, the second hydraulic pump motor and the third hydraulic pump motor to the volume discharged from or drawn into the rod oil chambers.

A rotary hydraulic machine with radial pistons comprising: a rotating shaft (2); a cylinder-housing body (3), having a plurality of housing seatings (4) arranged radially at equal distances from the rotation axis (R) of the rotating shaft (2); a cylinder (5) housed in each of said plurality of housing seatings (4) and rotating relative to the same around an axis (C) concentric with said rotation axis (R) of the rotating shaft (2); a piston (6) slidable in each cylinder (5) and coupled to a crank (7) of the rotating shaft (2); a supply conduit (12), for each cylinder (5), provided with a seal (120) arranged to enable a sealed connection between the supply conduit (12) and the respective cylinder (5).

Each seal (120) comprises: a first ring (121), arranged at an end of the supply conduit (12) and placed in contact with the cylinder (5); a second ring (122), concentric to the first ring (121) and interposed between the supply conduit (12) and the first ring (121), wherein the second ring (122) is coupled by interference with the first ring (121) and is inserted by interference into the supply conduit (12) in such a way as to prevent a rotation of the first ring (121) with respect to the supply conduit (12) around a common axis (X).

A rotary hydraulic machine with radial pistons comprising: a rotating shaft (2); a cylinder-housing body (3), having a plurality of housing seatings (4) arranged radially at equal distances from the rotation axis (R) of the rotating shaft (2); a cylinder (5) housed in each of said plurality of housing seatings (4) and rotating relative to the same around an axis (C) concentric with said rotation axis (R) of the rotating shaft (2); a piston (6) slidable in each cylinder (5) and coupled to a crank (7) of the rotating shaft (2); a supply conduit (12), for each cylinder (5), provided with a seal (120) arranged to enable a sealed connection between the supply conduit (12) and the respective cylinder (5).

Each seal (120) comprises: a first ring (121), arranged at an end of the supply conduit (12) and placed in contact with the cylinder (5); a second ring (122), concentric to the first ring (121) and interposed between the supply conduit (12) and the first ring (121), wherein the second ring (122) is coupled by interference with the first ring (121) and is inserted by interference into the supply conduit (12) in such a way as to prevent a rotation of the first ring (121) with respect to the supply conduit (12) around a common axis (X).

An object is displaced alternately in opposite directions, using a hydraulic power unit having a rotatable body which includes the shaft of a hydraulic machine having electronically commutated valves. A motor drives the rotatable body. The hydraulic machine drives an actuator to displace the object in use. Energy is transformed from rotational kinetic energy of the rotatable body to elastic strain energy or elastic strain and gravitational potential energy of the object during a pumping phase and rotation of the rotatable body slows, but does not change direction. The potential energy then drives the hydraulic machine to motor and the rotatable shaft speeds up again, storing rotational kinetic energy. The displacement of the hydraulic machine is controlled throughout to match a time varying demand taking into account the varying speed of rotation of the rotatable shaft. The motor provides energy to compensate for losses and the process can repeat cyclically.

A cam profile for a hydrostatic radial piston machine includes lobes positioned along a circumferential direction, each lobe comprising a lobe portion of rising type and a lobe portion of falling type. As the cam profile extends in the circumferential direction, a radial dimension of the cam profile mostly increases in each portion of rising type, and mostly decreases in each portion of falling type Shapes of at least two lobe portions of the same type are different.