Abstract: A push rod of a vacuum booster includes an inner rod section, a pipe-shaped outer rod section which is slidably fitted over an outer periphery of a rear portion of the inner rod section and connected to a brake pedal, and a buffer member made of a synthetic resin and fitted over the outer periphery of the inner rod section in front of the outer rod section. Usually, an end face of the outer rod section is retained in a position in which it abuts against a projection of the inner rod section. When an axial compressing force is applied to the push rod upon a collision of an automobile, the end face of the outer rod section slides forwards over and past the projection, while buckling the buffer member. Thus, the pushing-up of the brake pedal toward a vehicle compartment due to the retreating movement of a master cylinder is prevented, and the load applied to a driver's foot is alleviated.

Abstract: A hydraulic system for retracting into and extending out of the body of an aircraft a landing gear for use in taking off and landing, comprises a housing unit which has a hydraulic pump, a hydraulic actuator, a shuttle valve, an emergency valve, an actuator pressure releasing mechanism, and a mechanically locking mechanism accommodated therein. The hydraulic actuator has a piston rod assembly received therein to be reciprocably moved by the hydraulic pump to assume a retraction position and an extended position. The shuttle valve is movable with respect to the housing unit for selectively changing the flow of the hydraulic fluid between the hydraulic pump and the hydraulic actuator. The emergency valve is movable with respect to the housing unit to assume two different positions for selectively changing the flow of the hydraulic fluid between the hydraulic pump and the hydraulic actuator and the flow of the hydraulic pump and the fluid pressure reservoir.

Abstract: The deformation behavior of a transmission pin transmitting forces to the body fender of a motor vehicle and being found in the vacuum brake booster, is improved by equipping the transmission pins with predetermined breaking points or segments with smaller diameters.

Abstract: A hydraulic control device is disclosed, having a pressure connection and a tank connection and having a metering pump unit (4) that comprises at least two metering pumps (5, 6) connected hydraulically in parallel and operable mechanically in parallel and also a cut-off valve (8) in hydraulic connection between the two metering pumps (5, 6), the cut-off valve (8) being flange-mounted on a metering pump (6) and having in a housing (13) a slider member (12) which, under pressure form the pressure connection (P), is movable axially towards the metering pump (6). It is desirable to keep wear and tear to a low level such a control device. For that purpose, a displacement-limiting device (26, 28) for the slider member (12) is provided, which prevents the slider member from bearing on the metering pump (6).

Abstract: A fluid powered rotary actuator (10) having a stator (13) and a rotor (15) journalled with limited rotary motion within the stator includes at least one arcuate chamber defined between the rotor and stator and has an angularly movable vane (16) fixed to the rotor. There is a seal member (21, 23) at the vane for slidingly sealing a cylindrical sidewall surface of the stator thereby subdividing the arcuate chamber into two variable volume subchambers (25, 29; 27, 31). Pressurized fluid is ported selectively to one of the subchambers while a fluid egress path for fluid from the other of the subchambers allows the rotor to move angularly within the stator. There is a fail-safe aperture (22) in the cylindrical stator surface in a region traversed by the seal member and for conveying fluid from a selected one of the subchambers, as determined by the position of the vane, and a fail safe valve (24) coupled to and normally blocking the egress of fluid from a subchamber through the aperture (22).

Abstract: An improved adjustability and functional reliability of a device for time-dependent control of a duration of regeneration of an air dryer including a piston, which is longitudinally guided, displaceably counter to a resistance, in a cylinder by the force of a spring. The cylinder is closed by a cap, on which means for adjusting the prestressing force of the spring, supported at least indirectly on the cap, are provided. These means comprise a screw-wedge connection, which joins the cylinder and the cap to one another in such a way that by twisting the cap, an axial displacement of the cap relative to the cylinder is brought about. The device can be used for instance in air dryers for compressed air systems of motor vehicles.

Abstract: A power steering device includes a hydraulic pump for discharging working fluid, an actuator for producing a steering assisting force by means of working fluid, a hydraulic passage for connecting the hydraulic pump and the actuator, a check valve arranged to the hydraulic passage to allow flow of working fluid from the hydraulic pump to the actuator and preventing flow thereof in the opposite direction, an accumulator connected to the hydraulic passage downstream of the check valve, a pressure switch for detecting a pressure within the hydraulic passage downstream of the check valve, a control unit for controlling the hydraulic pump in response to the pressure switch, and a display for showing an anomaly of the power steering device. When determining the anomaly of the power steering device, the control unit stops the hydraulic pump and/or makes the display show the anomaly.

Abstract: A system (10) is provided for maintaining continuity of hydraulic power from an aircraft engine-driven hydraulic pump (28) to a first set of propulsion control hydraulic loads for controlling the aircraft engine (30). The engine-driven hydraulic pump provides hydraulic power to a second set of airframe hydraulic loads. The engine-driven hydraulic pump has a pump suction (26) having a first pressure and a pump discharge (34) having a second pressure that is greater than the first pressure. The system includes an accumulator (16) coupled to the engine-driven hydraulic pump suction, and the accumulator is chargeable at a third pressure that is less than the first pressure. A relief valve (18) is coupled to the engine-driven hydraulic pump suction, and the relief valve has a relief setpoint at a fourth pressure that is greater than the second pressure.

Abstract: A lift having a freight-receiving table which is rotatably supported by one or more each of hydraulic lift and tilt cylinders for respectively lifting and tilting the table is controlled such that an overloaded condition of the table is detected by measuring the internal pressure of the tilt cylinder or both the tilt and lift cylinders. If the measured pressure exceeds a pre-determined critical value, the operation of the lift is automatically and immediately stopped.

Abstract: An electrohydraulic tilting device for a vehicle with a tilting cab has a pump, an electric pump drive motor connected by way of an electrical connecting line to a source for electrical energy, and a hydraulic piston/cylinder unit connected to the pump. The piston/cylinder unit is designed for exerting a force which is capable of tilting the cab forward and back. An overcurrent protection device is provided which is designed for automatic interruption and subsequently maintaining the interruption of the electrical power line of the pump motor when the electrical power taken up by the pump motor for a predetermined period exceeds a first threshold value which is higher than the maximum electrical power required during normal tilting of the cab. The overcurrent protection device is provided with manual reset means for ending the interruption of the power line.

Abstract: A master cylinder (12) and pneumatic brake booster (10) assembly for use in a motor vehicle. The pneumatic brake booster (10) has a casing (15) fastened to a wall (16) which separates a cabin (H) from a front compartment (C) of the motor vehicle. The pneumatic brake booster (10) is actuated by control rod (18) having a rear end which is connected to a brake pedal located in the cabin (H). The master cylinder (12) has a body (20) formed with at least one flange (22) for fastening the master cylinder (12) onto the front wall of the casing (15). An aggressive element (26) extends from the body (20) and engages the casing (15) on rotation of the master cylinder (12) in response to a torque being applied to the master cylinder (12). Engagement of the aggressive element (26) with the casing (15) will attenuate the communication of the torque into the control (18).

Abstract: The main control servo valve responsive to electrical input signals modulates a power piston to position a throttle valve that varies the flow of fluid during normal operation. A transfer servo valve responsive to the pressure in the servo system moves hard over upon sensing a low pressure signal that is normally lower than the system's pressure to cause the power piston to position the throttle valve closed. In the preferred embodiment the system throttles compressor air of a gas turbine engine to provide an anti-icing function and activates the transfer servo valve upon a hard over malfunction.

Abstract: An air turbine flow restrictor comprises a sensor for determining the rotational velocity of the turbine wheel. In response to a detected speed above a predetermined threshold, particles are injected into the inlet airstream. In one embodiment of the invention, the particles are metal disks. The disks, carried by the airstream become lodged in the nozzles of the air turbine, thereby restricting the flow of air to the turbine wheel.

Abstract: A master cylinder comprising a body (4) pierced with a bore (5) closed on a first side by an end (6) and on a second side by a piston (7). The piston (7) slides in the bore (5) to delimit a pressure chamber (8). The pressure chamber (8) is connected by a pressure pipe (12) to at least one brake motor through an outlet (11) therein. The chamber (8) and the pressure pipe (12) together delimiting a working volume filled with a hydraulic fluid. The working volume is partially delimited by a leak-off device (19) which is responsive to an impact to selectively allow hydraulic fluid to leak off toward the outside of the working volume.

Abstract: A superhigh pressure generator system is provided which comprises first, second and reserve boosters 1, 2, 3 which are respectively provided with a plunger chambers 4a, 4b, 4c within single rod-type oil hydraulic cylinders 7a, 7b, 7c on the plunger side and are operative to pressurize water sucked into the respective plunger chambers to superhigh pressure, the boosters being connected in parallel each other to a water discharge line 9 via check valves 6a, 6b, 6c respectively. First, second and reserve 3-position directional control valves 13, 14, 15 are interposed between the oil hydraulic cylinders 7a, 7b, 7c of the respective boosters on one hand and first and second oil hydraulic pumps 11, 12 on the other hand so as to permit a reciprocating motion of the oil hydraulic cylinders. On-off valves 20, 21, 23, 22 are respectively provided on discharge lines 17, 18, 19, 16 which connect the three-position directional control valves 13, 14, 15 to the first and second oil hydraulic pumps 11, 12.

Abstract: An assembly of a pneumatic brake booster (100) and a master cylinder (200) for a motor vehicle. The pneumatic brake booster (100) has a casing (20) fixed to the bulkhead (10) of the vehicle. The casing is divided in leaktight fashion by a movable wall structure (22) into a front chamber (24) permanently connected to a source of partial vacuum and a rear chamber (26) connected selectively to the front chamber (24) or to the atmosphere by a valve means (16). The valve means (16) is actuated by a control rod (14) for actuating a push rod (28). The master cylinder (200) has a body (21) formed with at least first and second flanges (38, 38'; 40, 40'). The first and second flanges (38, 38'; 40, 40') interact with corresponding screws and nuts to fix the body (21) with the casing (20) of the booster (100). The body (21) has a bore (34) for slidingly receiving at least one piston (32) which is actuated by the push rod (28) of the brake booster (200).

Abstract: A servo-control system for actuating an aircraft flight control member, the system including at least one hydraulic actuator together with actuation means for actuating said actuator, said hydraulic actuator being duplicated, said actuation means including first and second actuation assemblies each comprising two hydraulic circuits each controlled by a respective mechanically-controlled distributor valve, the two distributor valves of the same actuation assembly being actuated by common mechanical elements caused to move by motor means, the actuation means including control means controlling said motor means as a function of the position of the flight control member and of piloting orders received by the control means, detection means for detecting failures, and a selector valve which controls switching of the actuation assemblies between an active state and a reserve state.

Abstract: The reliability of a fluid multiplexed actuation system is increased by arranging a pair of fluidic multiplexers in a parallel fluid flow path between a selector valve and several fluid actuators. Position sensors associated with the fluidic multiplexers and with the fluid actuators provide feedback signals to a microprocessor. In the event the feedback signals identify a malfunction in the fluidic multiplexer currently supplying fluid to the actuators, the microprocessor will deactivate the malfunctioning fluidic multiplexer and activate a redundant or back-up fluidic multiplexer by actuating the selector valve.

Abstract: A control apparatus comprises a plurality of servomechanisms for controlling a control surface of an aircraft. Each of the servomechanisms is equipped with a control valve for controlling the oil pressure in hydraulic chambers of the actuator assembly operatively connected to the control surface, and a switching valve provided between the actuator assembly and the control valve and shiftable to assume driving, bypassing and damper valve positions. The switching valves of the servomechanisms are shifted to assume the driving valve position in a normal operation. If one of the servomechanisms is damaged, the switching valve of the damaged servomechanism is shifted to assume the bypassing valve position. If all of the servomechanisms are damaged, the switching valves of the damaged all servomechanisms are shifted to assume the damper valve position.

Abstract: A system of modular electrohydraulic servovalves is centrally controlled may be used to control the operation of critical hydraulic actuators. A programmable controller operates a group of modular servovalves which each deliver a portion of the total actuator fluid requirements. The flow rate, valve position, and valve pressure of each servovalve is monitored by the controller and compared to expected values in memory to determine whether a servovalve malfunction exists. If so, the controller maintains the required flow rate to the actuator by closing the malfunctioning valve and either activating a spare or proportionally increasing the flow rates of the remaining servovalves to compensate for the loss.

Abstract: The invention relates to a low-vulnerability device for the operation of a lifting and propulsing helicopter rotor by means of a cyclic plate mechanism, in which the non-rotating plate (5) is coupled at four points (1, 2, 3, 4) to four hydraulic actioning servocontrols each comprising a power jack (9), an anchoring system (10) and a servocontrol-distributor (41, 42), three servocontrols being used when normally working, the fourth being used in back-up in the event of a failure of one of the other three. Each power jack (9) is supplied by an independent hydraulic circuit which comprises the servocontrol-distributor (41, 42) operated by a mechanical input, connected to the cockpit by linkage (13), and a disengageable anchoring system.

Abstract: A control system is provided for use with a hydraulic system which includes a source of pressurized fluid, a plurality of flow regulator means, and a plurality of fluidly powered components. Each flow regulator means is adapted to receive the pressurized fluid and is responsive to a respective control signal for regulating the flow of pressurized fluid to respective fluidly powered components. The control system includes a plurality of control members, each being movable to a plurality of locations for indicating a desired fluid output for a respective flow regulator means. A plurality of sensors are provided for sensing the position of respective control members and responsively producing respective position signals. A primary controller is adapted to receive the position signals, process the received signals to responsively produce the control signals, and deliver the control signals to the flow regulator means.

Abstract: A pair of orifices of different orifice sizes is provided between each pressure chamber and an accumulator chamber. A larger one serves as a variable orifice and a smaller one as a fixed orifice. The variable orifice becomes effective when a control circuit is functioning properly for variably controlling an axial position of a valve spool. The fixed orifice becomes effective when the control circuit malfunctions and allows the valve spool to be moved into a predetermined position. In another embodiment, a single orifice cooperates with the valve spool to serve as both a variable orifice and a fixed orifice.

Abstract: An actuator for raising and lowering aircraft landing gear in accordance with the extended and retracted state of the actuator includes a cylindrical casing, a piston assembly slidable along the axis of the casing, a fluid pressure source, a sealed chamber containing gas, a free piston forced by fluid pressure along the casing axis to compress the gas, latching devices for locking the piston assembly to the casing, a locking mechanism for holding the free piston in position on the pressure tube when the gas is compressed and hydraulic passages interconnecting the chamber containing pressurized gas and the space containing pressurized hydraulic fluid. A mechanism is provided for initiating automatic retraction of the actuator due to the effect of a self-contained perpetual source of compressed gas if hydraulic pressure is lost. A compression spring stores a force while the piston assembly moves between retracted and extended positions.

Abstract: A manifold is disclosed for converting a manual hydraulic steering signal into a proportional electrical signal. The manifold is connectable between a hydraulic fluid supply, such a helm pump, and a hydraulic steering cylinder and includes a rotary actuator responsive to variations in the flow of hydraulic fluid from the fluid supply. The manifold is useful for converting small marine vessels from manual to power steering and for providing emergency manual steering in large tankers and the like.

Abstract: Hydraulic power supplies for aircraft which have such hydraulically operated systems as flaps, ailerons, spoilers, rudders, elevators, brakes, and retractable and steerable landing gear. Typically, the aircraft will be of the multiengine type; and there will also be a multiplicity of hydraulic power supplies and engines. This scheme can be utilized to provide operating redundancy for the hydraulically operated devices of the aircraft. Each hydraulic power supply has a solid state controller which has a number of inputs as well as control and information providing functions. Control over the functioning of each hydraulic power supply can also be exercised by flight deck crew-operated switches which are connected to inputs of the solid state controllers.

Abstract: An actuator system for a control surface of an aircraft having a hydraulic system and a source of actuation system commands. The actuator system includes hydraulic circuits connected to the aircraft hydraulic system and an electrically-powered hydraulic circuit integrated with the actuator. The electrically-powered hydraulic circuit includes an electric motor connected to a hydraulic fluid pump. The pump can be controlled to adapt to the power requirements to actuate the control surface.

Abstract: In general, an auxiliary system for steering a vehicle includes a power steering unit coupled to the vehicle steering wheel so that the steering unit is thereby made capable of being manually powered by a vehicle operator for providing a supply of fluid at a first pressure. Valve means is connected between the steering unit and a pressure intensification device for selectively providing motive power to the device. Actuator means is connected between the device and the steering linkage of a vehicle for steering movement of the wheels. The intensification device is powered for rotation by the fluid at the first pressure when the steering unit is manually operated. The intensification device thereby delivers hydraulic fluid to the actuator means at a second pressure for steering the vehicle during auxiliary conditions.

Abstract: A dual hydraulic motor system where motor wobblers are mechanically linked and the motor outputs are torque summed, is controlled by a three position dual valve assembly. Each valve assembly is controlled by pilot pistons that are mechanically linked to provide three functions, one being normal operation, a second where one motor must be shut-off and its load on the system is minimized and the third where both motors are shut-off and significant drag is then provided. These functions are implemented by a separate spool in each valve which has three independent stable positions.

Abstract: A hydraulic system having an axial piston pump as a control pump which is regulated by a regulating device as a function of the demands with respect to volumetric flow and pressure of a load circuit supplied by it. On the suction side, the control pump is optionally provided with a partial amount of its maximum delivery volume by a feed pump, while the remaining part of the corresponding delivery quantity is drawn in directly from a storage container, bypassing the feed pump. Possibly impermissibly high vacuums on the suction side of the control pump are detected by a suction safety device which acts on the control pump via its regulating device so that the control pump delivers smaller quantities of hydraulic fluid unitl permissible operating conditions are reached.

Abstract: A power transfer unit coupling two otherwise separate hydraulic systems for bidirectional transfer of hydraulic power therebetween without transfer of fluid between the two systems. Control of the power transfer unit is effected using only hydraulic pressures, and static operation of the unit is maintained without power transfer until a determined pressure differential between the coupled systems is achieved to reduce wear and increase service life of the unit. Once dynamic power transferring operation of the unit is initiated, a pressure differential lower than the determined level is maintained between the two systems.

Abstract: A hydraulic motor has its lube drain connected to the motor return line. A motor seal protector valve has a pilot which responds to pressure in the motor return line. Normally, the valve connects system pressure to the motor inlet. High pressure in the return line causes the pilot to move the valve to block the motor feed line and then to connect the motor feed line to sump. In a preferred embodiment, system pressure is connected to the plot to "lock up" the valve in response to return line overpressurization.

Abstract: An actuator system is disclosed which modulates a linear output shaft associated with a working control valve or the like in response to a control signal input. The system includes a feedback control link, a pneumatic positioner, a pneumatically controlled hydraulic valving system and a hydraulic cylinder and piston assembly controlled by the hydraulic valving system. The hydraulic valving system includes a three-position, four-way valve actuated by pneumatic binary output signals from a signal conditioner which is in turn controlled by the positioner. Hydraulic flow to the three-position, four-way valve may also be controlled from the signal conditioner in response to positioner output for most effective actuation of the hydraulic cylinder and piston assembly. Failure modes are also disclosed with the present system. The resulting system exhibits extremely rapid response times and high accuracy with dynamic stability.

Abstract: In the supply of a power-assisted steering and an additional hydraulic system with fluid the power-assisted steering has priority so that when the steering is actuated the influx of fluid to the hydraulic system is correspondingly throttled by a priority valve. When a leak occurs in the hydraulic system, the influx of fluid to the hydraulic system is completely shut off when the oil level in the reservoir drops to a lower limit value. The closure of the priority valve is effected by a switch valve which is disposed in one of the control pressure lines of the priority valve and which is rendered currentless on response of the sensor for the fluid level.

Abstract: A vacuum system used with an automotive vehicle such that an appropriate negative pressure is maintained within the vacuum system in order to assure the function of the vacuum brake booster even when the vacuum clutch booster is defective with respect to airtightness. A vacuum system according to the present invention comprises a novel second check valve having an orifice formed in the poppet valve or in the valve body, being connected between the intake manifold and the vacuum clutch booster. The second check valve operates as an ordinary check valve in a normal condition but as an orifice in an abnormal condition to prevent the vacuum pressure in the system from being decreased quickly, without use of any conventional vacuum tank.

Abstract: A vacuum system used with an automotive vehicle such that an appropriate negative pressure is maintained within the vacuum system in order to assure the function of the vacuum brake booster even when the vacuum clutch booster is defective in airtightness. A vacuum system according to the present invention comprises a novel second check valve having an orifice therewithin, being connected between the intake manifold and the vacuum clutch booster. The second check valve operates as an ordinary check valve in a normal condition but as an orifice in an abnormal condition to prevent the vacuum pressure in the system from being decreased quickly, without use of any conventional vacuum tank.

Abstract: A pressure protection system including a valve for isolating an auxiliary fluid circuit from a main fluid circuit when a leak occurs in the auxiliary fluid circuit. A valve is connected between a governor controlled compressor and the main fluid circuit and a pressure protection valve is connected between the compressor and an auxiliary fluid circuit. If a leak develops in the auxiliary fluid circuit, the pressure protection valve closes which permits most of the output from the compressor to be used to recharge the main fluid circuit. The pressure protection valve includes a supply passage and a delivery passage disposed substantially perpendicular to the supply passage. A plunger member is movable within the delivery passage for closing the supply passage when there is insufficient fluid pressure in the auxiliary fluid circuit.

Abstract: A sluing mechanism driven by one or more electric or hydraulic motors, for excavating or bulk handling machines comprises a pivotable discharger boom mounted on a rotary support or turntable, and a coaxially pivotable superstructure carrying further equipment. The sluing drives of the two coaxially pivotable parts of the machine are connected to each other in such a way that upon pivoting the superstructure, the discharger boom does not follow this pivotal motion. The sluing drive of the discharge boom is designed as a superposed gear and connected to a drive motor for separately sluing the discharger boom. The turntable is provided with a second discharger sluing gear which is driven by a motor having a weaker characteristic than the drive motor or motors for sluing the superstructure. The characteristic of the motor driving the second discharger sluing gear may be adjustable.

Abstract: A riser tensioner safety system for preventing damage to a floating drilling vessel in a broken cable event or an emergency disconnect of the riser is disclosed. The system uses standard pneumatic/hydraulic tensioning devices together with a safety valve which is installed in the hydraulic fluid supply line to the tensioning device. The valve is held open by tension in the riser tensioner lines. If tension drops below a predetermined level due to a broken cable event or an emergency disconnect of the riser, the valve closes rapidly preventing acceleration of the tensioner piston.

Abstract: A hydraulic system having two pumps, typically driven by two independent prime movers, a primary and secondary reservoir and associated valving to permit the system to run as one system or two independent systems, all for the purpose of redundancy and safety. The system senses fluid level in the primary reservoir and actuates the valves to establish two independent hydraulic systems, each with its own reservoir, when the fluid level drops below a predetermined level. The system is particularly advantageous in twin-engine aircraft where three hydraulic systems are employed, one off of each engine, and the third system uses two pumps, one driven by each engine.

Abstract: A hydrostatic transmission (10) includes a variable displacement pump (12) for driving a fluid motor (14) in first and second directions. First and second high pressure conduits (20,22) connects the pump (12) and motor (14) in a continuous fluid circuit. A control pump (40) supplies make-up fluid to the first and second high pressure conduits (20,22) and simultaneously provides pressurized control fluid to a system control (50) for controlling the operation of the hydrostatic transmission (10). First and second low pressure conduits (24,26) are respectively disposed about the first and second high pressure conduits (20,22) and defines first and second spaces (28,30) therebetween. A pressure control arrangement (32) is connected to the first and second spaces (28,30) to control the maximum pressure level in the spaces (28,30) upon the failure of one of the high pressure conduits (20,22).

Abstract: The present invention is directed to an improved fail-safe actuator and hydraulic system incorporating the same. The actuator includes energy storage means in the form of a spring adapted to set a control device in a predetermined condition, illustratively in the closed condition, responsive to a failure situation, illustratively, a power failure. The actuator includes a coupling which permits normal operation of the control device without cycling the spring energy storage means, thus increasing the life of the spring and eliminating energy wastage inherent in cocking the spring during each operative cycle.

Abstract: A displacement control for a pump or motor having a swash plate for setting displacement includes a control device operatively connected to the swash plate and a control valve having connections to a source of pressure and drain for operating said control cylinder. The control valve has a neutral position wherein the swash plate is at or near a minimum displacement position. The control valve is operable to other positions for setting the displacement of the pump or motor and, additionally, is movable to a control position other than the neutral position or normal displacement-setting positions in response to an operative failure of the control valve positioning system which enables the swash plate to move to a position which minimizes any adverse effects from the occurrence of said operative failure. In a pump, the swash plate moves to a zero displacement position upon the occurrence of a failure while, in a motor, the swash plate moves to a maximum displacement position.

Abstract: A marine steering gear equipped with an emergency steering means which comprises an emergency directional control valve capable of replenishing hydraulic fluid or oil to a plurality of pressure chambers of an actuator for a hydraulic steering engine through check valves and stop valves, and a relief valve designed to set a desired charge pressure and installed in lines of oil to be supplied through the directional control valve, check valves, and stop valves so as to forcibly reduce the air volumes in the pressure chambers and thereby hold the rudder blade substantially in a hydraulically locked state.

Abstract: An actuator system is disclosed which modulates a linear output shaft associated with a working control valve or the like in response to a control signal input. The system includes a feedback control link, a pneumatic positioner, a pneumatically controlled hydraulic valving system and a hydraulic cylinder and piston assembly controlled by the hydraulic valving system. The hydraulic valving system includes a three-position, four-way valve actuated by pneumatic binary output signals from a signal conditioner which is in turn controlled by the positioner. Hydraulic flow to the three-position, four-way valve may also be controlled from the signal conditioner in response to positioner output for most effective actuation of the hydraulic cylinder and piston assembly. Failure modes are also disclosed with the present system. The resulting system exhibits extremely rapid response times and high accuracy with dynamic stability.

Abstract: A hydrostatically driven road roller having a swash plate pump controlling the supply of pressurized fluid to a drive motor, a dead man's handle or the like controlling pressurization of the fluid in the fluid system, a manual speed control lever connected to the swash plate pump, and a disconnectible device positioned in the connection between the control lever and the pump. The disconnectible device comprises a piston fixed to a swash plate control shaft, a cylinder movable on and lockable with the piston, and means for moving the cylinder into and out of locking engagement with the piston. Centralizing means are also provided to move automatically the swash plate into a neutral position.

Abstract: Hydraulic control.The unit is characterized in that it is provided, between an inlet well and an outlet well for pressurized fluid, with an obturator urged in the closed position by a resilient member arranged to act against the pressurized fluid in the inlet well in a chamber communicating with a conduit issued from the outlet well and separated from a return conduit by a relief valve which is urged in the closed position by a spring and by the fluid pressure prevailing in the inlet well.Application to transfer-machines with one single hydraulic station.

Abstract: A device of the type wherein a gas pressure is converted into an oil pressure and the resulting oil pressure is exerted to drive an actuator. A pair of gas-oil reservoirs are coupled with each other via a conduit wherein an automatic oil level control valve is disposed to close the conduit when the actuator is in operation and the gas pressure in the reservoirs are not balanced and open the conduit when the actuator is not in operation.

Abstract: A hydraulic motor drives the cooling fan of an internal combustion engine. Fluid flow from a fixed displacement pump is directed through a pilot-operated pressure-compensated control valve to the hydraulic motor. The valve has a continuous bias to a fan-on position for directing fluid to the fan motor. Flow to the fan motor is diverted by the valve as a function of the pressure of the fluid in the system. In addition, flow to the fan motor is diverted as a function of a pilot pressure signal which is controlled by the temperature of the engine coolant fluid. The valve failsafes to a condition directing maximum flow to the fan motor in the event of loss of pilot fluid pressure.

Abstract: An apparatus for delivering power to a marine propulsion device comprises an engine, a propeller, and a transmission which operatively connects the engine with the propeller and which is operative between a neutral position and a drive position. The apparatus further includes a source of pressurized fluid, a cylinder and a differential piston movable within the cylinder in response to pressurized fluid. A first conduit continuously conducts pressurized fluid from the source to the cylinder to locate the piston in a first position in the cylinder, and a second conduit conducts pressurized fluid from the source to the cylinder to locate the piston in a second position in the cylinder which second position is spaced from the first position. A flow control device communicates with the second conduit for selectively permitting the flow of pressurized fluid through the second conduit to displace the piston from the first position to the second position.