Abstract: Disclosed herein are various embodiments of a hydraulic actuator that includes one or more check valves having a dynamically varying cracking pressure. In certain embodiments, a hydraulic actuator may be configured to vary the cracking pressure of a check valve based on an operating condition of a pump of the hydraulic actuator. The check valve may be located along a bypass path in the hydraulic actuator, thereby allowing for fluid flow to bypass a pump of the hydraulic actuator by passing through the check valve. The use of such hydraulic actuators is contemplated in, for example, an active suspension system of a vehicle. Additionally, various embodiments of suitable check valves are disclosed. Additionally, methods are disclosed for operation of the check valve and the hydraulic actuator.

Abstract: A circuit pressure control unit includes a relief valve and a variable throttle valve. The relief valve is connected to a connecting passage communicating with an actuator upstream. The variable throttle valve is disposed upstream of the relief valve and is configured to change an opening degree thereof according to a control signal from a controller.

Abstract: A method for actuating a bypass control valve assembly of a fluid system includes receiving a first input signal at an electronic control unit. The first input signal is related to an active position of a direction control valve that is in fluid communication with a fluid pump and a fluid actuation device. The directional control valve includes a neutral position that provides fluid communication between a fluid inlet port of the directional control valve and a fluid outlet port of the directional control valve. A second input signal is received at the electronic control unit. The second input signal is related to the rotational speed of the fluid pump. The second input signal is compared to a limit. A drain valve of a bypass valve assembly is actuated so that fluid communication between the fluid pump and a fluid reservoir through the bypass valve assembly is blocked.

Abstract: A method for actuating a bypass control valve assembly of a fluid system includes receiving a first input signal at an electronic control unit. The first input signal is related to an active position of a direction control valve that is in fluid communication with a fluid pump and a fluid actuation device. The directional control valve includes a neutral position that provides fluid communication between a fluid inlet port of the directional control valve and a fluid outlet port of the directional control valve. A second input signal is received at the electronic control unit. The second input signal is related to the rotational speed of the fluid pump. The second input signal is compared to a limit. A drain valve of a bypass valve assembly is actuated so that fluid communication between the fluid pump and a fluid reservoir through the bypass valve assembly is blocked.

Abstract: A method for controlling an air servo cylinder apparatus includes an advancing process of advancing a piston up to a target position by controlling, by a controller, servo valves individually connected to a pressure chamber on the head side and that on the rod side of the cylinder, and a pressurizing process of subsequently applying a required pressurizing force to the piston. In the advancing process, the piston starts to be driven with the servo valve on the head side opened to the air intake side and the servo valve on the rod side opened to the exhaust side. Thereafter, the opening degree of the servo valve on the rod side is varied into an opening degree in accordance with a deviation of the current position from the target position, and thereby the piston is smoothly decelerated as it approaches the target position.

Abstract: Disclosed is an apparatus for a derrick, including hydraulic piston/cylinder arrangements for raising and lowering a yoke travelling on guide rails attached to the derrick. A hydraulic system having different modes of operation is provided for the operation of the piston/cylinder arrangements. The hydraulic system can operate in a normal mode for raising or lowering the yoke and in other modes by interconnecting upper and lower chambers of the piston/cylinder arrangements and utilizing a differential surface area of the piston exposed to the two chambers for rapidly raising or lowering the yoke.

Abstract: An oil-pressure cylinder in a crushing device is connected to a crushing jaw via a pivot shaft so that the crushing jaw can open and close. The extension of oil-pressure cylinder causes the crushing jaw to close and crush the object to be crushed. Oil-pressure cylinder has a piston with a greater pressure-receiving area on the head side than on the rod side. An acceleration valve serves to switch the extension/retraction operations of the oil-pressure cylinder. During a rod unloaded interval, beginning when the crushing jaw starts to close and ending when the crushing jaw comes into contact with the object to be crushed, the acceleration valve makes communication between a head-side port and a rod-side port in the cylinder continuous, while the oil path from the rod side to a tank is blocked. The oil from the rod side is made to flow to the head side.

Abstract: A decelerating air circuit having an air cylinder is disclosed. The decelerating air circuit includes a driving solenoid valve having an advance mode and a withdrawal mode. A decelerating solenoid valve having a high speed mode and a low speed mode has an outlet port connected to the decelerating solenoid valve. A constant speed flow control valve is attached to a low speed port of the decelerating solenoid valve. Limit switches are located respectively at an advance end and a withdrawal end of a piston rod of the air cylinder. Decelerating sensors are located respectively between the limit switches. The piston rod advances past a point of a decelerating sensor, triggers the sensor, and causes the decelerating solenoid valve's operating mode to change from a high speed mode to a low speed mode. The change in mode is accomplished by outgoing air being introduced so that it passes through the flow control valve thereby reducing the speed of the piston rod.

Abstract: A control system for controlling the movement of the ram of a press or press brake of the type having one or two main cylinders with pistons operatively attach to the ram. The control system comprises a programmable processor with inputs from a pressure transducer indicating the pressure applied to the one or two pistons and a linear potentiometer for each side of the ram to indicate ram position and levelness. The control system further includes a hydraulic circuit operated by outputs from the processor. The hydraulic circuit comprises a variable volume load sense-controlled pump supplying hydraulic fluid through a speed control assembly to a solenoid-actuated directional valve determining upward and downward movement of the ram. The speed control assembly comprises at least two lines connected to the output line of the pump and to the speed control assembly output line to the directional valve. At least one of the at least two speed control assembly lines is provided with a restricting orifice.

Abstract: The hydraulic circuit directional control valve 20 is provided in a line connected with a lower chamber 13 of the hydraulic cylinder 1 and the B-port of the servo valve 3. A check valve 22 permitting oil flowing into the P-port of the servo valve 3 from the lower chamber 13 is provided in the line in parallel with the hydraulic circuit directional control valve 20 and connected with the lower chamber 13 and the P-port of the servo valve 3. When making the ram 15 move downward with high speed, the hydraulic differential circuit is constituted by changing the hydraulic circuit directional control valve 20 such that the delivery oil exhausted from the lower chamber 13 returns to the P-port of the servo valve 3. The hydraulic oil supplied from the hydraulic pump 1 flows into the upper chamber 12 through the servo valve 3. The delivery oil exhausted from the lower chamber 13 returns to the suction side of the P-port of the servo valve 3 through the check valve 22, assisting the flow rate of the hydraulic pump 2.

Abstract: A fluidic power-assisted setting device has a setting motor having an output torque; a threaded spindle supported for rotation; a spindle nut threadedly mounted on the spindle for linear displacement; a setting member attached to the spindle nut for linear travel therewith; a gearing for transmitting the output torque of the setting motor to the spindle; a signalling device coupled to the gearing for generating an output signal when the linear force derived from the output torque of the setting motor is insufficient to overcome an external force opposing linear displacement of the setting member; and a fluidic power device including a hydraulic motor connected to the setting member for applying thereto a linear force to overcome the external force; and a hydraulic control valve hydraulically connecting the hydraulic motor with pressurized hydraulic fluid as a function of the output signal of the signalling device for causing the hydraulic motor to generate a force applied to the setting member for overcoming

Abstract: The servo device for controlling flow (10) situated in a branch hydraulic line (6), incorporates in a body (11) an inlet passage (12) and an outlet passage (9) connected by an intermediate passage (13) forming a seat (14) for a valve component (15) which is pushed against its seat by a spring (26) and by an electromagnetic actuator (16) via a push-rod (23) which is slidingly sealingly mounted in a bore (22) between the intermediate passage (13) and an internal chamber (19) which is connected to the inlet passage (12).

Abstract: In a handle steering force control mechanism adapted to stabilize steering feeling of a steering handle by imparting hydraulic reaction to a power steering device when the vehicle is travelling at high speed, a hydraulic control apparatus for supplying stabilized pressure oil to the power steering device and a hydraulic reaction chamber. This hydraulic control apparatus comprises a main spool and a sub-spool slidably inserted into the main spool to form a variable throttle whose open area is varied by relative displacement therebetween. This variable throttle, when the vehicle travels at high speed, closes the main valve side by the sub-spool and opens the hydraulic reaction side to increase reaction pressure. When reaction pressure reaches a predetermined value in response to steering pressure, the main spool is displaced by pressure oil to cut the reaction pressure.

Abstract: A pneumatic throttle control configuration provides synchronized start-up and independent shut-off of multiple pneumatic tools. Each tool includes a throttle control assembly having a manually operable throttle valve which selectively admits air to the vane motor of the tool and a spring-biased piston operably coupled to the throttle valve which maintains it in an open position in response to air pressure in a control line which interconnects the tools. The vane motor includes a governor controlled valve which opens at a predetermined motor speed and provides air to the control line and the pistons of each tool of the multiple tool arrangement, thereby opening every throttle valve. Each pneumatic tool may then operate and stall independently. When the last tool stalls, the control air flow to all tools is terminated and the throttle valves close.

Abstract: This invention relates to engine speed governor and is fully hydraulically actuated in proportion to sudden load changes of a steam turbo-generator engine. The invention comprises a transmitter and a receiver inter-connected by tubings. Oil pressure from the engine lubricating system through a pressure reducing valve is used as an operating power for the transmitter and the receiver for operating engine main control valve. The transmitter comprises a control valve having two axially spaced apart pistons and internal oil passages, a fixed spring and an adjustable concentrical spring acting on the top piston of the control valve, a variable spring acting on the bottom piston of the control valve and is seated on a stem which is connected to engine speed measuring device such as fly-weight by a push rod and a center rod.

Abstract: A flow control system for use in a power steering apparatus including a fluid cylinder for amplifying the manual steering torque and a control valve associated therewith. The flow control system is installed in a pressure fluid feed line which feeds fluid from a hydraulic pump to the fluid cylinder via the control valve.

Abstract: This invention relates to power tools and more particularly to an air-operated power tool commonly used for automotive or other assembly operations for installing threaded fasteners. The device of this invention shuts off the power tool as it approaches the stall condition. Motor rotation is sensed by transferring a small mass of air in proportion to the speed of the motor but independent of the air expanded to operate the motor. The air transferred is utilized to create a signal which through an air-operated valve shuts the power tool off when the speed is reduced below a predetermined amount as when the torquing cycle is nearing completion.

Abstract: A pressure gas engine in which pressurized gas such as air is supplied to a series of arcuately arranged nozzles for exhausting into a series of arcuately arranged impulse buckets thereby causing rotation of a rotor in which the buckets are located, each nozzle having an exit adjacent the buckets and each bucket having a curved surface with an entering boundary edge and a leaving boundary edge for the gas blast leaving the bucket so that the blast sweeps across the curved surface of each bucket. The exit diameter of each nozzle is less than the radius of the curved surface of each bucket to achieve a full sweep of each bucket's curved surface from the entering edge to the leaving edge.

Abstract: A power steering apparatus for a vehicle comprising: a hydraulic actuator for supplementing manual steering torque; a first valve means for controlling directions of pressure fluid supplied to the hydraulic actuator in response to manual steering; a second valve means for reducing the supplementing force of the hydraulic actuator by by-passing the pressure fluid; a vehicle speed detecting means for detecting the cruising speed of the vehicle; first switching means responsive to the vehicle speed detecting means for supplying electric energy to the second valve means when the cruising speed exceeds a predetermined value; and second switching means for decreasing electric energy supplied to the second valve means when the second valve means starts to by-pass the pressure fluid.