A hydraulic drive pump system incorporates: 1) a concentric, multi-lobed cam that produces multiple strokes per revolution; 2) a piston profile that maximizes the number of large-diameter pistons arranged radially around the centerline axis; 3) a flexible piston base 50 with internal oil flow; 4) hydraulically connected cylinders which counter displacement issues raised in item 2 above; 5) variable stroke capability leading to infinitely variable output the ability to disengage unneeded cylinders from the cam; 6) integral reservoir and accumulator capacity; 7) compact, external pressure and return manifolds; 8) axially-oriented pressure and return manifolds 60, 70, and 9) a hydraulic reservoir and pressure tank integrated into the body of the pump.

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.

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.

Presented is a piston pump comprising: a frame, a control element mounted in a rotatable manner about a central axis with at least one control surface, a plurality of cylinders having pistons displaceable therein, a suction connection for inflow of a fluid into the cylinders, a pressure connection for outflow of the fluid out of the cylinders. The cylinders are connected by lines to the suction and pressure connection. The cylinders, the pistons, and the control element are configured such that the position of the pistons in the cylinders can change by movement of the control element. The cylinders and the pistons are mounted so that they do not rotate completely about the central axis when the control element rotates. So that the piston pump can be operated with low maintenance, it is proposed that the cylinders or the pistons are connected respectively to a rotatably mounted roller.

Presented is a piston pump comprising: a frame, a control element mounted in a rotatable manner about a central axis with at least one control surface, a plurality of cylinders having pistons displaceable therein, a suction connection for inflow of a fluid into the cylinders, a pressure connection for outflow of the fluid out of the cylinders. The cylinders are connected by lines to the suction and pressure connection. The cylinders, the pistons, and the control element are configured such that the position of the pistons in the cylinders can change by movement of the control element. The cylinders and the pistons are mounted so that they do not rotate completely about the central axis when the control element rotates. So that the piston pump can be operated with low maintenance, it is proposed that the cylinders or the pistons are connected respectively to a rotatably mounted roller.

A wind turbine (1) comprising a turbine rotor (3) with one or more blades, a generator (4) and a drive train (5) interconnecting the turbine rotor (3) and the generator (4). The drive train (5) is provided with a main gear (6) directly driven by the turbine rotor (3). A plurality of pinions engages the main gear (6). Each of the pinions drives a hydraulic pump (7). A hydro motor (8) is connected to the respective pumps (7) via respective high pressure (9) and low pressure lines. The hydro motor (8) engages an input shaft of the generator (4). A planetary gear transmission (10) is arranged between each pinion and the respective hydraulic pump (7).

A propulsion system for an aircraft includes a propeller assembly, a controller, and a pump system. The propeller assembly includes a propeller and a power system, the power system including an electric motor and a motor converter. The controller is connected to the power system and configured to switch the power system into a power-off arrangement in response to a temperature of the motor converter being greater than a threshold temperature. The pump system includes a pump and a coolant circuit that cools the motor converter. The pump is coupled to the propeller and to the motor such that rotation of either drives the pump.

A propulsion system for an aircraft includes a propeller assembly, a controller, and a pump system. The propeller assembly includes a propeller and a power system, the power system including an electric motor and a motor converter. The controller is connected to the power system and configured to switch the power system into a power-off arrangement in response to a temperature of the motor converter being greater than a threshold temperature. The pump system includes a pump and a coolant circuit that cools the motor converter. The pump is coupled to the propeller and to the motor such that rotation of either drives the pump.

A system for supplementing the electric power needed by a pump jack electric motor, thereby reducing the electric power purchased from the local utility or power supplier. The system comprises a solar photovoltaic system, or other forms of renewable energy, and regenerated power from the electric motor or drive. The system can be both on-grid and off-grid. Battery banks and capacitor banks may be used to store energy.

A system for supplementing the electric power needed by a pump jack electric motor, thereby reducing the electric power purchased from the local utility or power supplier. The system comprises a solar photovoltaic system, or other forms of renewable energy, and regenerated power from the electric motor or drive. The system can be both on-grid and off-grid. Battery banks and capacitor banks may be used to store energy.