Abstract: An actuating system comprising a hydraulic actuator provided with a cylindrical cavity containing a piston configured to slide within the cylindrical cavity and a rod. The piston separates the cylindrical cavity into a first actuating chamber and a second actuating chamber. A first servo valve comprises a sheath including a first slider configured to slide within a cavity of the sheath on the basis of command signals from a command system. The cavity of the sheath comprises a first command chamber and a second command chamber on either side of the first slider. The first actuating chamber is fluidically connected to the first command chamber, and the second actuating chamber is fluidically connected to the second command chamber.

Abstract: Embodiments are directed to obtaining a first analog signal corresponding to a position error between a commanded gang output of a plurality of electro-mechanical actuators configured to be run in parallel with one another and a measured gang output of the plurality of electro-mechanical actuators, obtaining a second analog signal corresponding to an output torque, and processing, by a circuit, the first analog signal and the second analog signal to generate and output a discrete that indicates a status of the torque in terms of direction and magnitude.

Abstract: Embodiments are directed to obtaining a first analog signal corresponding to a position error between a commanded gang output of a plurality of electro-mechanical actuators configured to be run in parallel with one another and a measured gang output of the plurality of electro-mechanical actuators, obtaining a second analog signal corresponding to an output torque, and processing, by a circuit, the first analog signal and the second analog signal to generate and output a discrete that indicates a status of the torque in terms of direction and magnitude.

Abstract: A piston apparatus which configures an air bearing by introducing a compressed working media into an inside of a piston, and ejecting the working media from plural holes arranged on a circumferential portion of the piston into a clearance between the piston and the cylinder, which prevents a back-flow of the working media in the piston to a working space, and which readily secures reliability and longevity is provided.

Abstract: A hydraulically-actuated piston and barrel assembly includes a barrel defining an actuation fluid cavity and a piston bore, which includes an upper bore and a lower bore. A stepped piston is slidably received in the piston bore and moveable between a retracted position and an advanced position. The stepped top of the piston includes a first area that is separate from a second area. The first area and the upper bore define an upper cavity connected to the actuation fluid cavity through a relatively unrestricted flow area, when the piston is in its retracted position. The second area and the lower bore define a lower cavity connected to the actuation fluid cavity through a relatively restricted flow area when the piston is in its retracted position. The first area is exposed to fluid pressure in the upper cavity and the second area is exposed to fluid pressure in the lower cavity over a portion of the piston's movement from its retracted position toward its advanced position.

Abstract: A system and method for controllably positioning a hydraulic actuator which is operably connected to a control surface includes at least one main control valve for controlling the hydraulic pressure supplied to the actuator in response to a control signal indicative of a predetermined actuator position and at least one parallel control valve for supplying additional hydraulic pressure to the actuator in response to an error signal indicative of the difference between the position of the actuator and the predetermined actuator position to thereby correct for any differences indicated by the error signal. By correcting for any differences indicated by the error signal, the errors in positioning the control surface can be decreased and the stiffness of the control surface can be increased.

Abstract: A pneumatic cylinder includes a cushioning device having a first cushioning sleeve gradually decreasingly communicating a first cushioning chamber with a first passage formed on a first cap and connected to a first fluid flowing ports as the first cushioning sleeve is gradually inserted into the first passage; a second cushioning sleeve gradually decreasingly communicating a second cushioning chamber with a second passage formed on the second caps and connected to the second fluid flowing ports as the second cushioning sleeve is gradually inserted into the second passage; a first quick fluid exhaust valve which is mounted on the first cap and is selectively opened by pushing force of the piston to communicate the first cushioning chamber with the first passage; a second quick fluid exhaust valve which is mounted on the second cap and is selectively opened by pushing force of the piston to communicate the second cushioning chamber with the second passages; a first quick fluid supply valve which is mounted on t

Abstract: An electrohydraulic control system for a hydraulic working cylinder, for example of a press, the piston of which has a main working surface and a smaller working surface on the rod side. A low-pressure circuit is provided for the feed or retraction movement of the piston, and a high-pressure circuit is provided for the loading movement at increased feed force and reduced speed. The connection or disconnection of these two circuits, when required, is produced with two 3/2 way valves that are coupled together. To control these control valves, there is provided an electrical reference motor that drives a cam disk which brings about the deflection of the coupled control slide valves of the control valves against a spring. A mechanical feedback is provided via the power piston, so that altogether a closed hydromechanical position control circuit is formed.

Abstract: The present invention is a hydraulic hand-tool which includes an elongate piston having at least two sections of different transverse cross-sectional areas, a housing including a hollow front end portion having an interior surface defining a plurality of sections with different inner diameters corresponding in size, position and number to accommodate the sections of the piston in a manner which permits the piston to slide in a reciprocating manner within the hollow forward end of the housing and to define a main chamber and at least one auxiliary chamber for receiving hydraulic fluid as the piston slides in a forward direction; an hydraulic fluid conduit having a primary line with an end opening directly into the main chamber and at least one supplemental line communicating with at least one of the auxiliary chambers after the piston slides in a forward direction a predetermined distance; an hydraulic fluid or reservoir adapted to supply hydraulic fluid to another end of the primary line; and a pump in commun

Abstract: A compressed air power plant which includes a piston disposed within a cylinder and connected to a drive shaft. The piston is operated through a power stroke and an exhaust stroke upon each rotation of the drive shaft. The power plant includes compressed air means for supplying compressed air at a high pressure and at a second pressure lower than the high pressure. A distributing means is operatively associated with the compressed air means for selectively communicating the high pressure compressed air to the cylinder at the initial portion of the power stroke of the piston. An intake means is operatively associated with the cylinder and the compressed air means for selectively admitting compressed air at the second lower pressure to the cylinder at a predetermined time in the power stroke after the communication of high pressure air to the cylinder.

Abstract: Small-sized engine operated by an expanding gaseous fluid, which comprises a cylinder (18), a piston (20) and an inlet valve (38), the upper parts of the cylinder (18) and the piston (20) cooperating momentarily with a perforated (29) resilient membrane (28) circumferentially secured to the cylinder (18) and performing the functions of a pneumatic seal temporarily.

Abstract: In deep bore drilling it is usual to use a fluid operated percussive hammer to provide necessary drive for the boring operation. However a difficulty which is encountered with hammers which are currently in use is that the manufacture of the components for such hammers involves considerable amount of precise machining which not only increases the manufacturing cost of such units but also reduces the service life of the components. Some of the typical hammers in use generally comprise an outer cylindrical casing with a feed tube positioned concentrically within the casing and a piston slidably mounted within the casing and over the feed tube to reciprocate therein and impact on a drill bit mounted in and retained at the bottom of the casing.

Abstract: Valves are located at opposite ends of a cylinder and are automatically moved toward closed positions at a controlled rate as a piston approaches the ends of the cylinder. Upon being moved toward its closed position, each valve restricts the flow of exhaust air from the respective end of the cylinder and causes the piston to decelerate so as to cushion the piston as it comes to a stop.

Abstract: A system for resiliently supporting a load at a reference height includes a hydraulic cylinder for resiliently supporting a load about a reference height and an accumulator which cooperates with the cylinder for flowing hydraulic fluid therebetween in response to varying loads imposed on the cylinder. A valve is provided for dampening the rate of fluid flowing between the cylinder and the accumulator and a metering valve coacts with the cylinder for adjusting the reference height about which the load is supported.

Abstract: A pressure die casting machine having a working cylinder enclosing a working piston adjacent a multiplier cylinder having a multiplier piston slideably mounted therein. The working chamber intermediate the working piston and the multiplier piston is connected to a pressure medium supply line which includes a check valve. The check valve is separated from the pistons and is attached on the outside of the working cylinder and multiplier cylinder so that the pistons are not weakened and the valve is made accessible for maintenance. The supply of pressure medium to the pressure chamber is controlled by a valve arrangement actuable independently of the check valve.

Abstract: A hydraulic fluid feeding device for a power steering device is proposed which has a plurality of pumps for feeding hydraulic fluid to the power steering device and a flow path change-over valve for switching the paths between the pumps and the power steering device, wherein the feeding rate of the hydraulic fluid to the power steering device is controlled by the action of the flow path change-over valve. The flow path change-over valve is operated according to the magnitude of the load exerted on the power steering device so that hydraulic fluid from all the pumps combined is fed to the power steering device when the load is great, and the hydraulic fluid from at least one of the pumps is fed to the power steering device when the load is small. With this device, the control of the feeding rate becomes efficient. It also becomes possible to bypass the hydraulic fluid from some of the pumps to a tank, independently of the delivery rates of the pumps, so that the power consumption may be reduced.

Abstract: A carburetor equipped with an auto-choke device is disclosed wherein according to one embodiment a leak valve is disposed in a negative pressure chamber of a diaphragm device adapted to operate by a negative pressure in a suction passage downstream of a throttle valve so as to open a choke valve in said suction passage to a predetermined degree of opening (complete explosion opening) after an engine has rotated by itself, and when the diaphragm has executed a predetermined shift, the leak valve is opened, and simultaneously, the downstream of the leak valve is brought into the atmospheric pressure for engine temperatures below a set value and into the same negative pressure as that of the negative pressure chamber for engine temperatures at and above the set value, whereby the operating stroke of the diaphragm is changed-over in two stages in dependence upon the water temperature or oil temperature, and the complete explosion opening of the choke valve is changed-over in two stages so that it may become narro

Abstract: A fluidic driver amplifier for a servovalve has its controllably directed fluid jet differentially divided by a divider element which moves with a main valve piston in a manner to equalize the differential pressure received from the jet when the piston reaches the commanded position. In order to permit use of a small, low-leakage, fluidic driven amplifier, without the disadvantage of reduced speed of response, a derivative piston is linked to move with the main piston and displace fluid in a chamber containing a spring-centered secondary valve piston. When displaced, the secondary piston admits pressurized fluid into the main valve chamber in a positive feedback sense to aid the fluidic driver in positioning the main piston. The secondary piston is displaced only when the main piston is in motion and therefore has no effect once the main piston reaches the commanded position.

Abstract: Drive is transmitted from a cam to a push rod via a body of liquid trapped between two pistons. A control element is normally urged against a seat by pressure in the body of liquid but can be lifted off its seat by the application of pressure to liquid in a control chamber. When the control element moves clear of its seat, liquid trapped between the pistons acts on a seat-engaging face of the control element and displaces the control element instead of driving the push rod.

Abstract: A suction dredger, comprising a vessel and a suspension conveying conduit provided with a pump and having a nozzle suspended by means of at least one cable of a lifting device on the vessel, is improved for preventing breaking of the cable or damage of other dredger parts. To this aim the lifting device comprises a cable length variator having a piston movable in a cylinder, a pick-up system for picking up the travel of the piston, a fluid conduit communicating with the cylinder for supplying and discharging fluid and control circuitry for controlling the supply and discharge of the fluid so in dependence on the travel picked up by the pick-up system, that the piston is pushed backwards into a prescribed stretch.

Abstract: A positioning apparatus includes a master hydraulic positioning cylinder having a relatively long stroke capability and a train of additively connected, short-stroke pneumatic control cylinders for controlling the length of stroke of the master cylinder and thus the positioning of a variable-position tool such as a band saw. One end of the cylinder train is connected by a feedback rod to an extensible portion of the master cylinder. A connecting rod connects the opposite end of the train directly to the spool of a three-position servo valve which controls the flow of hydraulic fluid to and from opposite sides of the master cylinder. When air pressure is admitted to a selected side of a selected control cylinder, at least a portion of the train shifts initially in a direction to move the servo valve to an operating position to begin stroking the master cylinder in a desired direction.