Abstract: An adjustment apparatus for a pivot cradle of an axial piston machine includes an actuating piston configured to enable the pivot cradle to be pivoted about a pivot axis. The actuating piston delimits an actuating chamber by which pressure medium is configured to be applied to the actuating piston. The charging of pressure medium to and the discharging of pressure medium from the actuating chamber is controlled by a regulating valve. The regulating valve has a regulating piston configured to be adjusted by a solenoid. The regulating piston and the actuating piston are mechanically coupled to one another. Current is supplied to the solenoid depending on a setpoint pivot angle of the pivot cradle and depending on the previous state of the setpoint pivot angle, thereby largely reducing hysteresis effects of the solenoid.

Abstract: A two-step hydraulic valve is described. In an implementation, a two-step hydraulic valve with retrograde spool action has a pilot spool that controls hydraulic force applied to a main spool to switch a rod of a hydraulic actuator back-and-forth between extension and retraction. The main spool is hydraulically driven in retrograde motion to the pilot spool, providing improved reliability and switching action for the valve. The pilot spool also has an overtravel feature that can be used to hyperextend the rod for various purposes. In an example system, the two-step hydraulic valve controls a hydraulic actuator connected to drive a submersible reciprocating pump, such as a diaphragm pump.

Abstract: This invention relates to an actuator assembly for a turbocharger pressure control valve assembly and a method of assembling a pressure control assembly of a turbocharger. The assembly comprises an actuator coupled to an actuator rod which in use is coupled to the valve assembly to control the position thereof. The actuator rod comprises an elongate member at least a portion of which is flexible. The actuator rod may be a resilient member which may be substantially straight when stressed. In use the actuator rod may extend in a substantially straight line between the actuator and the valve assembly.

Abstract: The present invention relates to a vacuum brake booster for a motor vehicle brake system, having a force input element that is connectable or connected to a brake pedal, a chamber arrangement comprising a vacuum chamber and a working chamber that are separated from one another by a movable wall, a control valve with a valve element for selectively connecting and separating vacuum chamber and working chamber, and a force output element for transmitting an output force to a master cylinder, wherein the force input element is workingly connectable or connected to a transmission piston arrangement disposed in the control valve, wherein the control valve is settable in accordance with a displacement of the transmission piston arrangement along a longitudinal axis by means of the force input element. In this case, it is provided that the transmission piston arrangement is provided with at least one pressure compensation channel, by means of which a pressure compensation is effected at the valve element.

Abstract: This invention relates to an actuator assembly for a turbocharger pressure control valve assembly and a method of assembling a pressure control assembly of a turbocharger. The assembly comprises an actuator coupled to an actuator rod which in use is coupled to the valve assembly to control the position thereof. The actuator rod comprises an elongate member at least a portion of which is flexible. The actuator rod may be a resilient member which may be substantially straight when stressed. In use the actuator rod may extend in a substantially straight line between the actuator and the valve assembly.

Abstract: An integral power steering apparatus includes a stroke limiter. A piston defines two hydraulic chambers in a housing. A communicating passage, a first valve disposed between the first hydraulic chamber and the communicating passage, and a second valve disposed between the second hydraulic chamber and the communicating passage, are provided to serve for a stroke limiter, in addition to a hydraulic circuit for supplying hydraulic fluid to the two hydraulic chambers. The two valves each include a valve body having a bore and serving as a valve seat, a plunger slidably fitted within the bore of the valve body and serving as a valving element, and a spring disposed on the bottom of the bore of the valve body and biasing the plunger to be in contact with the valve body.

Abstract: A power steering system for motor vehiles, fitted with a rotary disk valve and comprising a reaction piston (1) defining an active (2) and a passive reaction chamber (3). A servo pressure can be fed to the reaction chamber (2) in order to modify the actuating force on the steering wheel. A damping piston (4)is arranged on the active reaction chamber (2) in order to receive dynamic oscillations of the reaction pressure.

Abstract: A control valve and a method of controlling fluid flow include an input device which provides an input for moving a primary valve member an amount which is a function of the input, thereby opening flow pathways through the valve. The control valve is connected to a mechanical feedback mechanism which moves a feedback valve member an amount which is a function of the movement of a device to which the fluid flow is directed, such as a hydraulic actuator. Movement of the actuator to a desired position causes the second valve member to be moved to such a position that, in combination with the first valve member, the flow pathways through the valve are closed. The actuator is thereby moved to and maintained at the desired position without the need for the electronics feedback sensor used in prior art systems to sense actuator position.

Abstract: A boosted braking system for a motor vehicle having a master cylinder (200) and a pneumatic booster (100). The master cylinder (200) causes an increase in pressure of brake fluid supplied to at least one wheel brake (300). The pneumatic booster (100) is controlled by the application of an input force (F2) to a control rod (26) to actuate the master cylinder (200). A main hydraulic piston (30) of the master cylinder (200) has a hollow cylinder (32) in which a reaction piston (34) slides in a leaktight and axial direction. The reaction piston (34) receives at least the input force (F2). An elastic member (46) located between the reaction piston (34) and hollow cylinder (32) exerts an elastic force for urging the reaction piston (34) toward the master cylinder (200). The reaction piston (34) delimits within the cylinder a reaction chamber (36) which is isolated from the interior volume (V) of the master cylinder (200).

Abstract: A servo operation apparatus for a transmission comprising an input shaft to which the shift-change operation force is mechanically transmitted from a shift lever, a servo unit for boosting the shift-change operation force by feeding a working fluid, and a valve device which feeds the working fluid to, or drains the working fluid from, the servo unit depending upon the shift-change operation of the shift lever, wherein provision is made of an working fluid feed control means which feeds the working fluid in such a manner that the pressure of the working fluid in the servo unit is raised with a steep gradient in the former half until a predetermined initially raised pressure value is reached and, thereafter, is raised in the latter half with a gradient less steep than that of said former half.

Abstract: A booster for a transmission gear box has an actuating rod cooperating with a gearshift lever and a hollow piston rod movably penetrating the pneumatic cylinder and cooperating with the actuating rod. A connector is mounted to the piston rod and introduces and discharges pressurized air into and from the piston rod. A striker is coupled to the actuating and piston rods through a pin and is coupled to a connecting lever of the gear box to allow the connecting lever to be operated in conjunction with the actuating and piston rods. The booster prevents a relative rotating motion between the actuating and piston rods, simplifies the gearshift part of the gear box, smoothly engages and disengages gears to the gear box with a small force and provides an easily-machinable hollow piston rod.

Abstract: The invention is a mechanical-type position-sensing and feedback system employed between a main stage spool valve and a pilot stage spool valve of an electro-hydraulic servovalve. The feedback mechanism makes use of a rotatable feedback link that directly senses the position of the slide of the main stage valve and transforms a linear motion of the slide into a linear movement of the sleeve of the pilot stage valve. The feedback link has an elongated body and is adapted for rotation about its body's longitudinal axis.

Abstract: In an auxiliary power steering intended especially for motor vehicles, a pinion (2) positioned in a steering housing (1) engages a steering rack (9). A steering valve (14) that is used to control the pressure medium for the auxiliary power steering provides two inlet-seat valves (15, 16) and two outlet-seat valves (17, 18) whose closing bodies (20, 21, 35, 36) can be shifted in the axial direction by a rotary movement of a steering spindle. Closing bodies (20, 21) of inlet-seat valves (15, 16) can be biased in the closing direction by the force of pressure springs (22, 23). In the process, pressure springs (22, 23) bias the closing bodies (20, 21) of inlet-seat valves (15, 16) only if the particular outlet-seat valves (17, 18) are in their neutral position. Each pressure spring (22, 23)--when steering valve (14) is in the neutral position--keeps closing body (20, 21) of the particular inlet-seat valve (15, 16) resting against a valve seat (26, 27) that is fixed on the housing.

Abstract: The invention relates to a vacuum-operated servo-brake comprising, in a casing consisting of a shell (10) and a cover (12), a piston (20) separating leaktightly two inner chambers (22, 24), a valve means controlled by a rod (32) projecting from the casing in order to ensure the operation of the servo-brake, and a prestressed spring (34) for returning the piston (20) to its rest position substantially abutting the cover (12), the spring (34) bearing on the shell (10). According to the invention, the spring (34) comprises a mechanism enabling its extension to be limited when the shell (10) and the cover (12) are not fixed to each other.

Abstract: A liquid pressure booster includes a power piston slidably disposed in a housing, a power chamber in the housing on one side of the power piston, the power piston having a stepped bore including smaller and larger diameter bores, the latter opening into the power chamber, a supply passage communicating the smaller diameter bore to a pressure fluid source, a first valve seat in the smaller diameter bore, a valve element slidable in the smaller diameter bore to seat upon the first valve seat from the side nearer the pressure fluid source, an annular pin abutting the valve element side nearer the larger diameter bore to move the valve element away from the first valve seat, a discharge passage axially through the annular pin and communicating between the power chamber and a reservoir, and a second valve seat formed on the free end of the annular pin to interrupt communication between the power chamber and the discharge passage upon abutment of the annular pin against the valve element, a stepped sleeve having sm

Abstract: The assembly comprises a brake-booster and a master cylinder having, in an outer casing (10), a space divided in leakproof fashion into a front chamber (12) and a rear chamber (14) by a movable partition (16), at least a first resilient mechanism (18) tending to displace the movable partition towards the rear chamber. The front chamber is connected to a vacuum source, and a pressure difference is established between the front and rear chambers by a valve mechanism (20) capable of connecting the rear chamber to the atmosphere upon actuation of a control rod (22) in order to displace the movable partition towards the front chamber. A master cylinder (30) is fixed on the front wall of the casing and has a bore (40) in which a tappet (42) integral with the movable partition and delimiting an enclosed space (28) in the master cylinder slides in leakproof fashion. This tappet has a bore (32) in which a reaction piston (24) subjected to the pressure of the enclosed space (28) slides in leakproof fashion.

Abstract: In order to eliminate the noises caused on operation of a vacuum brake power booster, a radially outwardly extending air-conducting surface (26), which tapers toward a poppet valve member (7) closing a sealing seat (19) and which is opposite to the channel (25) on actuation, is adjacent to the radially outwardly disposed area of the sealing seat (19) designed on a valve piston (10), the sealing seat being released on displacement of the valve piston (10) and permitting inflow of the atmospheric air into the working chamber (3) of the booster via a radially extending channel (25).

Abstract: A brake booster includes a housing in which a constant-pressure chamber and a variable-pressure chamber are defined by a power piston. An input rod is operatively connected to one end of the power piston and receives an input force. A valve is provided in the power piston and operatively connected to the input piston so as to open upon receipt of the input force in such a manner that the differential pressure between the chambers moves the power piston. An output rod is operatively connected to the other end of the power piston. A wall member is provided across which a first auxiliary chamber at a side of the variable-pressure chamber and a second auxiliary chamber formed at a slide of the constant pressure are formed. An orifice passage connects the variable pressure chamber and the first auxiliary chamber.

Abstract: The brake booster comprises a housing (10) in which is displaced a driving piston (12) having a hub (14) and separates a front chamber (16) from a rear chamber (18), the front chamber (16) is connected to a source of fluid under a first pressure, the rear chamber (18) is capable of being connected to a source of fluid under a second pressure, and the driving piston (14) is capable of being displaced from a rest position in response to the establishment of a difference between the first and second pressures between the two chambers (16, 18) and the pressure difference is controlled by a valve mechanism (20) associated with input control members (34, 62, 60). The connection (62) between the rear chamber (18) and the source of fluid under the second pressure is made by the input control members (34, 62, 60).

Abstract: The invention relates to a hydraulic pressure booster which can be used to perform servo control of input and output at the preset servo ratio in, for example, a brake booster. In particular, the invention relates to a hydraulic pressure booster, which is designed to reduce the loss stroke of an input shaft in the initial stage of operation. This can be achieved by providing a stopper which directly abuts the input shaft when it is non-operational and which maintains the input shaft at the preset advance position separated from the detent in relation to the power piston.

Abstract: A liquid pressure booster which may be used in a brake booster or the like is disclosed. A second supply passage is provided which allows a power chamber of the liquid pressure booster to communicate with an external source of pressure fluid without passing through a valve mechanism of the liquid pressure booster. A first open/close valve is operative to open or close the second supply passage, and a second open/close valve is effective to open or close a discharge passage of the liquid pressure booster. A controller controls the first and the second open/close valve. With this construction, the controller may be caused to open the first valve and to close the second valve to allow the pressure fluid to be introduced into the power chamber through the second supply passage without depressing a brake pedal to cause a forward movement of an input shaft. In this manner, the liquid pressure booster can be operated automatically, and thus such booster can be advantageously used in an automatic braking unit.

Abstract: A throttle-controlled hydraulic power brake employing a pressurized fluid produced via a pump and preferably stored in an accumulator for enabling servo-assisted displacement of a push rod acting on the master cylinder of a brake pump (of the same type employed on vacuum-operated power brakes) subsequent to axial displacement of a second push rod controlled directly by the brake pedal. Displacement of the second push rod towards the first provides, against the action of elastic means, for opening a first face seal valve, which feeds the pressurized fluid into a variable-volume accumulating chamber, so as to displace a piston connected axially to the first push rod and defining a movable wall of the accumulating chamber, and so close the valve. Opposite displacement of the second push rod, on the other hand, provides for opening a second face seal valve connecting the accumulating chamber to a drain.

Abstract: A parking sustainer which allows a vehicle to be maintained parked by continuing a braking action if the depression of a brake pedal is terminated. An open/close valve is disposed in a liquid pressure discharge passage usually provided in a liquid pressure booster, and control means closes the open/close valve when a set of conditions to maintain the vehicle parked are satisfied. The provision of the open/close valve in the discharge passage of the booster eases the space requirement for its mounting and facilitates a maintenance inspection or repair.

Abstract: A pneumatic boost device includes a booster input including a manually actuatable upstream pusher and a downstream pusher positioned such that the movement of the upstream pusher towards the piston causes the upstream pusher to contact and move the downstream pusher toward the piston. A compressed gas is supplied to the cylinder such that the piston is moved in a direction away from the booster input by a system including a gas flow path having a first check valve, the first check valve being seatable on a seat moving with the downstream pusher. Movement of the downstream pusher thus applies a gas pressure to the piston which moves by an amount corresponding to that of the upstream pusher. The downstream pusher has a piston in the additional cylinder. Another gas flow path has a second check valve, the second check valve being seatable on a seat moving with the upstream pusher by movement of the upstream pusher toward the piston.

Abstract: A brake booster which includes a control slide that is displaceably supported in a servo piston and acted upon by a piston rod under the influence of brake pressure. The control slide has bores that establish communication between a pressure chamber and a pressure source or return for power brake fluid in the pressure chamber. The control slide is intended to penetrate a control bush in a stepped bore in the servo piston, which has a radial bore for connecting the pressure source with a radial bore in the control slide toward the pressure chamber. The control bush is supported radially movably in the stepped bore.

Abstract: A hydraulic brake booster is proposed, in which a coupling is provided between a control valve and a booster piston. The coupling engages the control valve at a slide sheath and upon the movement of the booster piston causes it to move as well, in such a manner that tracking control is provided. A pedal push rod in this manner always keeps a certain distance from the booster piston; that is, it does not touch it. However, if the auxiliary force should fail, then the pedal push rod does touch the booster piston, and its force is transmitted mechanically.

Abstract: A hydraulic idling-regulating valve comprising at least two mechanically operated through-flow valves which can be controlled to move alternatively into a flow position and a closure position and which are both closed in a neutral central position. An electromechanical specified-value setting system positions the piston of a hydraulic drive cylinder, which system comprises a hollow shaft that can be rotated by a number of revolutions correlated with the specified value, and an actual-value feedback system is provided which comprises a feedback spindle which is in engagement with an internal thread of the hollow shaft and which performs a number of revolutions correlated with the piston movement. The valve-actuating element is subjected to the same displacements as the specified-value setting shaft.

Abstract: In a servo-valve arrangement, a control piston is displaced as a function of steering forces to be applied which control piston in its turn controls throttling places in such a manner that a piston-cylinder aggregate is acted upon with a pressure difference and produces a force assisting the steering movement. A throttling section connected in parallel with the piston cylinder aggregate includes throttling places controlled by external parameters as well as by the system pressure and makes it possible to act upon the end faces of the control piston with a pressure difference in order to permit a force opposing the respective displacement of the control piston to act on the control piston. As a result thereof, an undesired overcontrol of the servo-valve arrangement, respectively, of the steering system controlled thereby is avoided.

Abstract: A hydraulic booster device comprises a booster cylinder coupled with a rear end of a cylinder body of a master cylinder, a booster piston slidably received in a piston guide mounted in the booster cylinder and spring-biased in a retreating direction, a valve piston connected to an operating member and slidably received in the booster piston, an output hydraulic pressure chamber defined to face a back of the booster piston, an input hydraulic pressure chamber leading to a hydraulic pressure supply source, an inlet valve interposed between the input and output hydraulic pressure chambers and opened in response to the advancing operation of the valve piston relative to the booster piston, an outlet valve interposed between the output hydraulic pressure chamber and an outlet chamber leading to an oil reservoir and closed in response to the advancing operation of the valve piston relative to the booster piston, and a booster chamber facing a back of the operating piston and defined between the operating piston and

Abstract: In an actuating drive for valves, the stroke motion of the servo piston has to be transmitted to the return sleeve in the control block, so that this results in that hydraulic feedback which restores the equilibrium at the servo piston. By means of a lever or a single-point mounting, this same stroke motion is directly transmitted to a pin attached in an eccentric position relative to the center axis of the return sleeve and transmitted from this pin to the return sleeve adjoining thereunder.

Abstract: A steering wheel end shaft part and a gear end shaft part are connected together elastically by means of a mechanism located between the shaft parts, the relative rotation between the shaft parts being converted into a large-stroke pivoting movement of a setting lever which actuates a control valve unit of the power steering system.

Abstract: A power-assisted gear shift mechanism for a manual transmission includes a lateral casing mounted on a transmission housing, a first lateral shaft rotatably mounted within the casing and being operatively connected to a manual shift lever to be rotated in shifting operation of the shift lever, and a second lateral shaft in the form of a hollow shaft rotatably and axially slidably mounted on the first lateral shaft and being operatively connected to the manual shift lever to be axially moved in selecting operation of the shift lever, the second lateral shaft being integrally provided with a shift-and-select lever which extends into an interior of the transmission housing to be selectively engaged with a plurality of shift heads in axial movement of the second lateral shaft.

Abstract: There is disclosed a combined servo control and jack unit which comprises a casing, an actuated piston slidably disposed in a piston chamber and having a piston rod extending outwardly of the casing. A servo valve chamber, axially parallel to the piston chamber, has slidably mounted therein a spool and also a sleeve member which is mechanically connected to the piston rod. Shifting the spool in either axial direction directs hydraulic fluid to one or the other side of the piston, thus moving the latter until spool stopping, at which time the sleeve automatically, almost instantly, blocks off the flow in the new position. A variable speed, gradual action of the piston is obtained without hydraulic shock or cavitation.

Abstract: In a pneumatic position controller for controlling the position of a pneumatic servomotor (10) to a value determined by a pneumatic command pressure, the command pressure acts through a movable wall member (30) on a pivotable balancing member (40). The balancing member (40) controls through a baffle plate (52) the outlet nozzle (56) of a pneumatic amplifier (24). The balancing member (40) is axially spaced from a feedback lever (44), with aligned pivot axes. A helical torsion spring (50) has one end attached to the balancing member (40) and the other end attached to the feedback lever (44). The feedback lever (44) is rotatable by the servomotor (10). An advantageous and compact construction permitted by the use of the helical torsion spring (50) is described.

Abstract: A power assistance device has a double acting piston and cylinder whose piston rod is connected to an output. Compressed air is passed via a pair of air pressure regulators to opposite sides of the piston. Each regulator has a regulator spring, and the regulators are housed in a body which is moved upon manual effort being applied to an input to cause the springs to differentially bias so decreasing pressure on one side of the piston and increasing pressure on its opposite side, creating a pressure differential across the piston causing it to move with its piston rod to apply a magnified load to the output which is proportional to the manual effort applied to the input. The regulators could be set so that in a neutral position of the power assistance device, zero pressures exist on opposite sides of the piston. In an alternative arrangement a pair of single acting piston and cylinder devices could be used.

Abstract: An unbalanced hydraulic valve assembly includes a first plunger element slidably and transversely displaceably received in a second plunger element wth a loose fit; a work chamber; a pressure supply conduit provided in the valve assembly for introducing pressurized hydraulic fluid thereinto; a control port arrangement in one of the plunger elements in an asymmetrical relationship relative to the circumference of the plunger elements. The control port arrangement permits or blocks flow from the pressure supply conduit to the work chamber dependent upon the relative axial position between the plunger elements. A force transmitting member is supported in the second plunger element for displacement transversely to the direction of relative axial motion between the plunger elements. The force transmitting member engages the first plunger element and is exposed to pressurized hydraulic fluid for pressing the first plunger element against an inner wall face of the axial bore provided in the second plunger element.

Abstract: The servomotor comprises a piston assembly (9) provided with a tubular hub (25) sliding on a valve sleeve (11) provided with a return roller (51) for a flexible elongate member (40) fixed between an end wall (4', 43) of the casing and an arm (47, 48) of the piston assembly normally extending beyond the return roller (51), between the latter and said end wall.

Abstract: A brake booster of the stroke-enlarging type which includes a power piston disposed in a casing for being actuated by a difference in pressure on opposite sides thereof. The brake booster includes a transmission device in the form of a ball and ball retainer which are biased by a spring while the ball is retained between a surface of the power piston and a control piston. The ball and ball retainer are limited in movement by a stopper coupled to the power piston. The ball and ball retainer forming the transmission device are advanced in response to the spring bias by the power piston and are operated such that when a brake clearance has been extinguished and a reactionary force from the output member becomes larger than the preload of the spring, the reactionary force blocks the advance of the ball and ball retainer so that the reaction force is partly transmitted to the control piston with a resultant reduction of the reactionary force transmitted to the power piston.

Abstract: Two fluid passages are connected through flow restrictors to a fluid supply. Downstream of the restrictors the fluid supply has a drooping pressure-load characteristic. Venting means for the fluid passages comprises vent openings therein downstream of the restrictors and variable position obstructor means cooperating with vent openings to vary venting and thereby vary fluid pressures in the fluid passages.Fluid conduits connect these pressure outputs to a double acting piston moving in a cylinder whose opposite ends are connected to the fluid conduits. The piston and cylinder form the responder of the system.A receiver is formed by a piston and cylinder or other fluidic motor remotely fluidically connected to the responder, the motor driving a load.A feedback means controlled by the position of the responder piston and/or the load varies pressure in the fluid conduits by variably venting same.Both rotary and linear types of transmitters and load feedback means and receivers may be used.

Abstract: A brake booster of stroke-enlarging type which includes a casing, a power piston so disposed as to divide the interior of the casing into two chambers for being actuated by the difference of pressure in the two chambers, a control piston, containing therein a valve mechanism for controlling the difference of pressure in the two chambers and a transmission mechanism for transmitting an input of an input member to an output member, being coaxially fitted into a central bore of the power piston relatively movably thereto and a reaction lever, which is abutted at an output portion in the middle thereof by the output member, receiving output of the transmission mechanism and output of the power piston respectively as an input at a first input portion and a second input portion thereof located on either side of said output portion in the middle, whereby a greater stroke can be obtained at the output member than a stroke input at the input member.

Abstract: Disclosed is a pump comprising a rotatable barrel, a tiltable pump cam, and a proportional servo actuator operatively connected to the pump cam to affect the angle between the pump cam and the axis of the barrel.

Abstract: A hydraulic force multiplying device has a housing having an inlet port connected to a source of hydraulic pressure and an outlet port, an input rod and an output rod, one end of each of the input and output rod being slidably connected with one another within the housing, a free piston slidably disposed between the outer circumference of the input rod and the inner wall of the housing and dividing the interior of the housing into an inlet side oil chamber and an outlet side oil chamber, the free piston being associated with the output rod, a passage formed in the input rod for connecting the two oil chambers, and a valve for controlling oil flow in the passage. The valve consists of a valve member and a valve seat provided respectively on either the input or the output rod and the other of the input and output rods. The valve is formed to allow the relative movement between the input and output rods in the valve closing direction with the valve member engaging with the valve seat.

Abstract: A process for controlling pneumatic servomotor of the type comprising a control by a motor jack supplied with pressurized fluid by a pressure modulator of said fluid and a first slaving loop causing said jack to slave in a given reference position, wherein each reference position is stored in analogue manner by movable mechanical friction means carrying said modulator and displaced by means of a second disengageable slaving loop which is substituted for the first during reference position changes and which takes its displacement energy for the movable mechanical means directly from the motor jack.

Abstract: A servo mechanism for adjusting the position of a biased control member of a sliding ring for controlling pressure fluid in a main conduit of a hydraulic machine, comprises a manually adjustable sleeve, a setting piston arranged for reciprocating movement in the sleeve and being hydraulically connected thereto to resume a position preset by the sleeve, a follower piston coupled between the setting piston and the biased control member of the recoiling device, a control pressure space provided above the follower piston, a unidirectional first control conduit delivering a regulating stream of pressure fluid from the main conduit to actuate the setting piston, a second control conduit between the main conduit and the pressure space, and a flow controlling valve controlled by pressure in the first control conduit for equalizing pressure between the pressure space and the main conduit thus allowing override of the setting piston during the pressure setting operation.

Abstract: A brake booster of the stroke enlarging type wherein a power piston operated by the pressure difference existing on opposite sides thereof is moveable relative to a control piston provided with a control valve for controlling the difference of the pressure, and the power piston and the control piston are engageable to be immovable relative to each other by means of a locking member after the pressure difference has reached a predetermined value. The power piston is so constructed as to be able to advance a larger distance than the control piston, while the pressure difference is small, to move the output member by a larger amount in comparison to a small amount of advancement of the input member of the booster.

Abstract: A valve actuator is disclosed having a servo-motor which regulates the position of a main valve that controls steam supply to a turbine. A hydraulic input signal acts on a pilot valve within the valve actuator body to move a valve spool in response to the input signal. Movement of the valve spool permits oil to flow into a cylinder in which the servo-motor is located. The flow of oil into the cylinder causes a piston which is a part of the servo-motor to move upwardly. Movement of the servo-motor is regulated by a cam and follower arrangement which transfers the motion of the servo-motor to a valve sleeve. The valve sleeve, which has a differential piston area, shuts-off the supply of oil to the servo-motor. The cam and follower arrangement provides for a linear correlation between the hydraulic input signal and the operation of the servo-motor. Increased closing forces provided by the differential piston reduce vibration of the valve sleeve and the servo-motor.

Abstract: A fluid repeater system may be balanced so that displacement of the load has a desired correspondence to displacement of the transmitter. This may be done by making the fluid resistance offerd to fluid flowing along a path from the source to the reservoir and through the feedback controlled directly by the load, exclusive of the resistance offered by such load feedback, approximately equal to that offered to fluid flowing along a path from the source to the reservoir and through the transmitter, exclusive of the resistance offered by such transmitter.

Abstract: The dynamic performance of hydraulic apparatus including a fluid-operated actuator controlled by a servo-controller, is improved by providing phase lead compensation to the controller in response to movement of the movable element of the actuator so that the low frequency response of the apparatus is raised.

Abstract: A lever with a powered accessory for forcing against a resistance so that an initial manual operation can be applied to the lever and subsequently a powered force will be applied to the lever. The powered apparatus is shown to be a fluid cylinder assembly attached with the lever for assisting the pivot of the lever, and linkage attaches to the lever and extends to a valve or the like which is to be operated and which presents the resistance to be overcome. Fluid switches are disposed adjacent the lever and are activated according to the initial pivoting of the lever for controlling the flow of fluid to the cylinder assembly and thus to achieve the power assist in the pivot of the lever and the actuation of the resisting valve.

Abstract: A fluid pressure operable servo positioner for selectively positioning a mechanical member or lever by a power cylinder selectively positionable in accordance with the degree of operating fluid pressure supplied thereto through a control valve device at a pressure determined by the degree of a selectively variable control pressure supplied to the control valve device, the power cylinder including a counteracting spring for balancing the force of the operating pressure to maintain the power cylinder in the selected position and a cam member engaging the control valve device and positionable according to the position of the power cylinder for maintaining the control valve device in the selected pressure supply position.