Abstract:
Apparatus for providing actuation power to an aircraft flight control surface. The apparatus includes a first actuator and a second actuator, where the second actuator has a bypass mode and an assist mode. The mode of the second actuator is determined by a load on the first actuator. When the second actuator is in the bypass mode, the first actuator provides the actuation power for the aircraft flight control surface. But, when the second actuator is in the assist mode, both the first and second actuators provide the actuation power for the aircraft flight control surface. Accordingly, the apparatus allows the flight control surface to be operated in a more efficient manner with less hydraulic flow being required.
Abstract:
A device for controlling a working arm of a working machine, which is capable of releasing the pressure of the actuation fluid confined in the actuation cylinder of the working arm device at a predetermined pressure lower than the set pressure and of controlling the opening/closing of the cylinder relief valve. The device comprises releasing means for a releasing a pressurized fluid feed/drain circuit of an actuation cylinder of a working arm device at a predetermined pressure lower than a set pressure of a cylinder relief valve provided for said feed/drain circuit and a control means for controlling the opening/closing of the releasing means.
Abstract:
The present invention provides a construction machine with a structure of pilot pipe comprising detection ports for detecting pilot pressure in a body of a switching valve, so that the number of pipe connecting positions and pipe assembly parts such as joints and the like can be decreased and arrangement of the pipe can be simplified.
Abstract:
A power machine includes one or more steerable wheels. The wheels are steerable using a hydraulic actuator to drive steering movement of the wheels. The power machine also includes steering angle sensors which sense the steering angle and provide a signal indicative of the angle at which the wheels are disposed relative to a longitudinal axis of the power machine. A hydraulic control system controls pressure of hydraulic fluid provided to the steering actuators based upon the steer angle position and desired change in position over time sensed by the steer angle sensors.
Abstract:
A hydraulic control system has a closed center control valve disposed to control flow of pressurized fluid from a pump to an actuator and a bypass valve disposed to control fluid flow through a bypass line connecting the pump to a reservoir. A controller connected to the control valve and the bypass valve is operative to controllably move the control valve toward an open, flow communicating position and the bypass valve toward a closed flow blocking position. A pressure compensating valve is disposed in the bypass line to maintain a predetermined pressure differential across the bypass valve when the pressure upstream of the bypass valve exceeds a predetermined level so that the flow through a area opening in the bypass valve is substantially commensurate with the opening at pressures above the predetermined level.
Abstract:
In a displacement control system for a variable displacement type hydraulic pump for supplying a discharge pressurized fluid of the variable displacement type hydraulic pump to an actuator via a direction control valve and then controlling a displacement of said variable displacement type hydraulic pump for maintaining a pressure difference between a discharge pressure of said variable displacement type hydraulic pump 1 and a load pressure at a portion between a direction control valve and an actuator, wherein an inlet side pressure of said direction control valve is detected as said discharge pressure.
Abstract:
An apparatus for adjusting the pressure of working fluid provided to the load or user via a hydraulically actuatable control valve is provided. The apparatus includes a comparator that compares a given or desired control pressure for the control valve with the predominant present load pressure. The resulting pressure differential is used to re-adjust the control valve or to re-adjust a pressure compensator positioned upstream of the control valve with respect to the direction of the flow of working fluid flowing to the user.
Abstract:
A load measuring device for an oleopneumatic load intensifier apparatus which causes a rapid advance of a tool carrying piston rod followed by slow advance of the piston rod at an increased load. the oleopneumatic apparatus has a master cylinder and an actuating cylinder that can assume different positions with respect to the master cylinder while maintaining fluid communication therewith. An enclosed hydraulic system is shared by the master and actuating cylinders. Pneumatic pressure actuates a piston within the master cylinder that causes a rapid advancement of a hydraulic fed piston withihn the actuating cylinder, causing a piston rod and a tool associated therewith to contact a workpiece. The load measuring device monitors the load associated with the pneumatic pressure applied to the piston and associated piston rod, located in the master cylinder and the resultant force applied to the hydraulic fed piston located within the actuating cylinder to precisely determine the load delivered to the workpiece.
Abstract:
A fluid power apparatus particularly useful for an industrial robot which includes a pair of expansible chamber devices each having a pair of control chambers in fluid communication with each other to intensify the working fluid output pressure and a working chamber that expands to receive a charge of working fluid and contracts to expel working fluid therefrom. A working fluid circuit includes a first line connected with one of the working chambers and a second line connected with the other of the working chambers. A fluid actuator is connected with the circuit and has a moveable element that moves in response to flow of working fluid in the circuit to the actuator. The apparatus has a static condition in which the one working chamber is contracted with the moveable element of the actuator stationary in a first position. A control mechanism is operable in response to a demand to change the position of the moveable element from the first position to a second position to sequentially alternately contract and expand the working chambers, respectively, to cause flow of working fluid to the actuator and move the element to the second position and thereafter restore the static condition.
Abstract:
A pressure compensated load responsive flow control valve for use in a system controlling a plurality of loads. The system is powered by a single, fixed displacement pump. The flow control valve is equipped with a load responsive control, which during simultaneous control of multiple loads automatically maintains the pump discharge pressure at a level higher by a constant pressure differential than the pressure required by the largest load being controlled and which while system loads are not being controlled using external source of pressure fully opens pump bypass and reduces the pump bypass pressure to a minimum level.