Multi-rotor hydraulic drone (1) comprising: —a plurality of hydraulic motors (6) each receiving a pressurised fluid, —propellers (5) driven by the hydraulic motors (6), —at least one hydraulic pump (10) driven by at least one motor (11) for pressurising the fluid, —a system for supplying the hydraulic motors (6) with pressurised fluid, —a flight controller (14) for controlling the supply system according to the desired rotation speed for the hydraulic motors (6), the supply system comprising several channels (35; 36; 37; 38) for adjusting the power of at least one portion of the hydraulic motors (6).

A hydraulic system of a construction machine includes: control valves interposed between a variable displacement main pump and hydraulic actuators; and first solenoid proportional valves connected to pilot ports of the control valves. The hydraulic system further includes: a regulator that changes a displacement of the main pump; and a second solenoid proportional valve connected to an auxiliary pump by a primary pressure line, the second solenoid proportional valve outputting a secondary pressure to the regulator through a secondary pressure line. A switching valve is interposed between the auxiliary pump and the first solenoid proportional valves, and includes a pilot port that is connected to the secondary pressure line by a pilot line.

To improve operability and work efficiency while achieving reduction of the number of parts and simplification of circuit structure, in a hydraulic control system equipped with hydraulic actuators whose hydraulic power sources are both the first, second hydraulic pumps. The hydraulic control system is provided with the stick directional switching valve; the main-side, sub-side supply oil passages connecting the hydraulic pumps to the stick directional switching valve; and the stick flow rate control valve which is placed in the sub-side supply oil passage, and controls the supply flow rate from the hydraulic pump when the supply flow rate to the stick cylinder requires the supply flow rates from both the hydraulic pumps, wherein the stick directional switching valve is configured such that the discharge flow rate control is performed in the entire area of the spool stroke, and the supply flow rate control is performed at the first region of the former half of the spool stroke, but not performed at the second region of the latter half of the spool stroke.

A selector control that is manually operable by a user for activating or deactivating a primary control or a secondary control. The selector control may include a first state for activating the primary control and deactivating the secondary control, a second state for activating the secondary control and deactivating the primary control, and a failsafe state for deactivating both the primary control and the secondary control. The selector control may be configured to maintain the second state independent of continuous user input being applied to the selector control, and configured to maintain the first state when continuous user input is applied to the selector control. The selector control is normally biased toward the failsafe state such that the selector control automatically selects the failsafe state when the user discontinues applying the user input for maintaining the first state. The selector control has particular application for use in controlling a boom of a work vehicle.

Disclosed is a turbine fracturing apparatus. The turbine fracturing apparatus includes: a main power assembly and an auxiliary power assembly. The main power assembly includes a first power source and a piston pump connected to the first power source; the first power source outputs power to the piston pump, and the piston pump outputs a first liquid. The auxiliary power assembly includes a second power source, a load sensitive system connected to the second power source, and an auxiliary power device; the second power source outputs power to the load sensitive system, the load sensitive system is connected to the auxiliary power device and outputs a second liquid for the auxiliary power device. The first liquid is different from the second liquid, and the first liquid and the second liquid have certain pressure. The load sensitive system is configured to regulate a pressure of the second liquid in real time according to pressure of the second liquid required by the auxiliary power device.

An emergency braking method for aircraft, comprising using a progressing parking brake controlled by a lever (10) that can be actuated by the pilot between a “0%” position in which the brakes are connected to the return pressure of the aircraft, and a “100%” position in which the brakes are connected to the feed pressure of the aircraft, the lever being blockable in the 100% position in order to provide parking braking when the aircraft is stationary. According to the invention, the emergency braking method being characterized in that it comprises: using a valve having an outlet port connected to the brakes, a return port, and a feed port, the valve presenting a state connecting the outlet port to the return port and a state connecting the outlet port to the feed port; and controlling the valve to occupy one or other of those states by pulse width modulation (PWM) having a duty ratio (R) that is a function of the position of the lever in order to deliver the brakes with pressure lying in the range return pressure to feed pressure, depending on the position of the lever.

An emergency braking method for aircraft, comprising using a progressing parking brake controlled by a lever (10) that can be actuated by the pilot between a “0%” position in which the brakes are connected to the return pressure of the aircraft, and a “100%” position in which the brakes are connected to the feed pressure of the aircraft, the lever being blockable in the 100% position in order to provide parking braking when the aircraft is stationary. According to the invention, the emergency braking method being characterized in that it comprises: using a valve having an outlet port connected to the brakes, a return port, and a feed port, the valve presenting a state connecting the outlet port to the return port and a state connecting the outlet port to the feed port; and controlling the valve to occupy one or other of those states by pulse width modulation (PWM) having a duty ratio (R) that is a function of the position of the lever in order to deliver the brakes with pressure lying in the range return pressure to feed pressure, depending on the position of the lever.

A hydraulic distributor includes at least one main spool configured to define a delivery branch, and a discharge branch, a feed branch and a pressure compensator configured such that a local pressure acts on a first side thereof and a maximum Load Sensing pressure acts on a second side characterizing either the working pressure of the hydraulic section, in the case in which there is only one hydraulic section, or, in the case in which there is a plurality of hydraulic sections, each one defining a respective characteristic pressure, of the maximum pressure among the characteristic pressures of the hydraulic sections. The pressure compensator is arranged such as to respectively intercept said delivery branch and said discharge branch.

A hydraulic system includes: a slewing motor; a mechanical brake; and a slewing control valve interposed between a main pump and the slewing motor. A first pilot port of the slewing control valve is connected to a first solenoid proportional valve by a pilot line. A second pilot port of the slewing control valve is connected to a second solenoid proportional valve by a second pilot line. The first solenoid proportional valve and the second solenoid proportional valve are connected to an auxiliary pump by a primary pressure line. A switching valve is interposed between the auxiliary pump and the mechanical brake. The switching valve includes a pilot port that is connected to the first pilot line by a switching pilot line. The valve switches from a closed to an open position when a pilot pressure led to the pilot port becomes higher than or equal to a setting value.

A hydraulic system includes: a slewing motor; a mechanical brake; and a slewing control valve interposed between a main pump and the slewing motor. A first pilot port of the slewing control valve is connected to a first solenoid proportional valve by a pilot line. A second pilot port of the slewing control valve is connected to a second solenoid proportional valve by a second pilot line. The first solenoid proportional valve and the second solenoid proportional valve are connected to an auxiliary pump by a primary pressure line. A switching valve is interposed between the auxiliary pump and the mechanical brake. The switching valve includes a pilot port that is connected to the first pilot line by a switching pilot line. The valve switches from a closed to an open position when a pilot pressure led to the pilot port becomes higher than or equal to a setting value.