Abstract: Provided are hydraulic systems comprising variable speed drives coupled to hydraulic pumps and methods of operating such systems. The drive speed is controlled based on the position of a hydraulic servo-control valve in order to reduce the flow through a bypass line. Specifically, the drive speed may be decreased as the valve is opening and sending a greater portion of the hydraulic fluid into the bypass line. This approach allows to reducing losses in the bypass line thereby increasing the overall efficiency of the hydraulic system. The position of the hydraulic servo-control valve may be determined using a position sensor or a flow sensor. Alternatively, the position may be estimated by increasing the drive speed and monitoring the pressure change in the hydraulic actuator. The differential pressure-speed ratio obtained during this speed increase is compared to a calibration set of values corresponding to different valve positions.

Abstract: A control assembly (20) for overcoming a rotational resistance required to activate supplementary steering force associated with conventional power steering systems. The control assembly (20) includes a shaft (26) subject to rotational resistance via a torsion bar (62). A valve assembly (22) has a first hydraulic circuit (76) that is interchangeable from an unassisted condition (36) to an assisted condition (34) for providing supplementary steering force to a steering gear after the rotational resistance of the torsion bar (22) is overcome by rotating the shaft (26). An actuator (38) includes a second hydraulic circuit (86) interchangeable from an unengaged condition (42) to an engaged condition (40) applying circumferential force on the shaft (26) to overcome the rotational resistance of the torsion bar (62) and rotate the shaft (26) from a non-rotated position thereby activating the supplementary force of the first hydraulic circuit (76).

Abstract: A hydraulic system associated with an engine may include a hydraulic pump, a hydraulic tank, a hydraulic starter and a second pump. The hydraulic system may include a relief valve that allows hydraulic fluid to pass through the relief valve when pressure at the relief valve meets a predetermined pressure. As well, the hydraulic system may include a first solenoid valve and a second solenoid valve. The first solenoid valve may be coupled between the hydraulic pump and the second pump to thereby control fluid flow to the second pump. Additionally, the second solenoid valve may be coupled between the hydraulic pump and the hydraulic starter to thereby control fluid flow to the hydraulic starter.

Abstract: In one exemplary embodiment of the invention a method for controlling a speed of an internal combustion engine includes shutting off fuel flow into a cylinder to reduce the speed of the internal combustion engine. The method also includes providing an electrical load to an alternator of the internal combustion engine, further reducing the speed of the internal combustion engine.

Abstract: A fluid controller includes a first fluid meter defining a first plurality of volume chambers and a second fluid meter defining a second plurality of volume chambers. A selector assembly, disposed between the first fluid meter and the second fluid meter, includes a selector plate defining a bore and a selector valve disposed in the bore. The selector valve is adapted for rotational movement between a first position and a second position and includes a first face and an oppositely disposed second face. The selector valve defines a plurality of thru-passages that extend axially through the first and second faces and that is adapted to provide fluid communication between the first and second volume chambers in the first position. The selector valve defines a groove disposed on the second face. The groove recirculates fluid from the second plurality of volume chambers when the selector valve is in the second position.

Abstract: A hydraulic steering arrangement includes a steering valve, a steering motor, connected with a high-pressure connection and a low-pressure connection via the steering valve, and with a steering unit, connected via the steering valve with a pilot pressure valve, whose outlet is connected with the low-pressure connection. It is endeavoured to improve the steering behaviour. For this purpose, the pilot pressure valve is opened, before the steering valve creates a connection between the high-pressure connection and the steering motor.

Abstract: A method of individually adjusting auxiliary hydraulic valves for work vehicles is provided such that they provide different maximum flow rates for opposite flow directions through the valve. The valve is controlled by a flow rate control for setting a maximum flow rate and is also controlled by a proportional control input device having one range of positions for providing a corresponding first range of flow rates in the one direction, a central position for providing substantially no flow, and another range of positions for providing a corresponding second range of flow rates in the other direction.

Abstract: Hydraulic steering arrangement (15) with a steering handwheel (2), which is connected with a manual. pump (3), a pump (18) supplying hydraulic fluid, a steering motor (12) and a steering valve (15) arranged between pump (18) and steering motor (12) and having a valve element (20) steering the flow of hydraulic fluid between the pump (18) and the steering motor (12), the valve element (20) being displaceable by hydraulic pressures originating from the manual pump. In such a steering arrangement it is wanted to create the opportunity of implementing various functions, without having to abandon the ordinary hydraulic control. For this purpose, the valve element (20) has an additional drive (31).

Abstract: A hydraulic valve apparatus is for controlling pressurized fluid flow to at least a pair of coupled hydraulic actuators in response to operator signals. The valve apparatus comprises a main body having main ports communicating selectively with a fluid supply and fluid return, body ports to communicate with the actuators, and a scavenge port to communicate with the return. Each actuator communicates with two control valves and one scavenge valve on the valve body to control fluid flow relative to the actuators. Control devices cooperate with the control and scavenge valves of each actuator so as to actuate the respective valves simultaneously. The control devices maintain the two related control valves in the same phase with respect to each other, but in an opposite phase to the respective scavenge valve.

Abstract: A brake valve (45) is disclosed of the type which permits communication from a source (11) of pressurized fluid to a brake actuator (47) in response to manual movement of a valve spool (57) from a neutral position (FIG. 2) to a power brake position (FIG. 5). In the power brake position, the valve spool permits fluid communication between a work port (53), which communicates with a brake actuator, and a brake load signal chamber (87), the brake load signal controlling the fluid output of the source. As the valve spool moves toward a manual brake position (FIG. 6) communication between the work port and the brake load signal chamber is blocked. In the manual brake position, movement of the valve spool causes a large piston (63) to displace fluid from its piston bore (73) into a piston bore (75) in which is disposed a small piston (61), the small piston being operable in response to movement of the valve spool to build brake pressure in the work port (53).

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: Flow amplified control systems are useful in pilot operated steering systems. The load responsive flow amplified control system includes a directional control valve movable to an operating position to direct fluid from the operating fluid circuit through a variable orifice to a steering motor and to direct control fluid from a control fluid circuit through another variable orifice to be combined with the fluid going to the steering motor. The operating fluid circuit and the control fluid circuit are provided with fluid from a common variable displacement pump. The directional control valve is moved to an operating position by the control fluid acting thereon and is pressure compensated insofar as the flow of control fluid passing through the another variable orifice such that a substantially constant predetermined pressure differential exists across the another variable orifice.

Abstract: In a steering system in which both front and rear wheels are steerable, the rear road wheels are adapted to be turned in the direction opposite to the direction of turning of the front road wheels only when a steering wheel is turned with a torque or effort larger than a predetermined value.

Abstract: The disclosure relates to a control system for actuating a turret carrying a weapons system in an armored vehicle. An electrically actuated hydraulic system moves the weapons system in elevation and azimuth directions in driving the system toward a target. A manual pump backup is provided to effect movement in elevation when the automatic system is disengaged. A supercharger reservoir delivers makeup fluid to the pump under pressure to prevent cavitation. A variable capacity hydraulic motor is employed to drive the turret through the azimuth. Features described include various subsystems as well as the entire system.

Abstract: The invention relates to a reaction hydraulic control unit for use in steering systems of the type having a differential type servomotor. In steering systems of this type having a differential piston type servomotor there exists a condition during the piston centering operation when the unit is in neutral wherein the servomotor piston has a slower centering speed when the transfer of medium is from the nonrod side to the rod side of the servomotor. The unequal centering times causes annoyance to drivers because that condition is transmitted to the steering wheel. This problem is addressed by providing steering controlled valving for exhausting fluid from the nonrod chamber of the servomotor to the system tank after the control unit has returned to its neutral position and during the centering operation of the servomotor piston.

Abstract: The invention relates to a steering assembly having a bidirectional servomotor of the differential piston type which is connectable to steerable wheels. A directional control valve unit has a spool valve with two collars which cooperates with the housing to form first and second end control chambers and a middle chamber. A power circuit supplies pressurized fluid equally to the end control chambers and a manually operable control pump is operable to selectively and incrementally increase and decrease the pressures in the end chambers in a push-pull mode to effect movement of the servomotor piston in either direction. The control valve has two ports connected to opposite ends of the servomotor with one port providing fixed and constant fluid communication between the first valve chamber and one side of the servomotor.

Abstract: The invention relates to a reaction or open center type hydraulic steering control system which is adapted for use with a bidirection differential type servomotor having a piston rod extending from only one side thereof. A loaded check valve in a selected one of the lines to the servomotor compensates for relatively low above atomospheric pressures sometimes present in the line leading from the open center passage of the control unit to the exhaust tank when the control unit is in a neutral position.

Abstract: The invention relates to a steering control system for a bidirectional servomotor connectable to steerable wheels. The servomotor may be of the differential type in which a rod extending from one side of the piston thereof causes the effective areas on opposite sides of the piston to be unequal. A steering control unit controlled by a steering wheel has two motor ports connected to opposite sides of the servomotor and pump and tank ports connected to pump and tank units. The steering control unit has a metering motor controlled by the steering wheel which meters fluid to and away from only one side of the servomotor. The steering control unit has oppositely acting valves which may be throttle valves for establishing flow paths for opposite steering directions and the neutral condition.

Abstract: The distributing device of a vehicle hydraulic control system comprises a distributor connected via hydraulic lines to a servomotor, a pump and a tank, the control member of the distributor being mechanically connected with the steering drive shaft, and further includes a hydraulic machine connected via hydraulic lines with the hydraulic distributor, the rotary member of this machine being adapted to vary the volume of the working chambers and being mechanically connected with the actuating member of the hydraulic distributor and with the steering drive shaft, the steering drive shaft being rotatable relative to the rotary member of the hydraulic machine within an angular play value providing for the preset displacement of the control member of the hydraulic distributor.

Abstract: A differential drive arrangement interconnects positive displacement pumps with a manual actuating mechanism of an auxiliary fluid power steering system for vehicles to compensate for variations in fluid outflow from the pumps pressurizing two servomotors through two fluid operating circuits. Check valves in the two fluid circuits are arranged to maintain operation of only an appropriate one of the differentially driven pumps through one of the two fluid circuits when a pressure loss occurs in the other of the fluid circuits.

Abstract: A steering control with a hydraulic follow-up wherein a movable valve member of a control valve is automatically brought back to a nonsteering disposition as a result of the movement of the device being steered to the desired steering position. Movement of the device is effected by a pair of steering cylinders. Control of the movable valve member is effected by a variable volume storage device which receives hydraulic fluid from the control valve and returns the fluid to the control valve as a function of the relationship of the steering mechanism and device to be steered.

Abstract: The invention relates to a power steering system of the metering type. Units of this type most commonly utilize gerotor type gear sets for the metering operation. During emergency operation when pressurized operating fluid is not available from a pump, steering is accomplished by operating the metering motor with the steering wheel which provides a pumping function for manually creating pressurized fluid. A problem with this type of unit is that a substantial amount of manual exertion is required to steer the vehicle under these conditions. Control units of this type have a universal drive between the rotatable valve thereof and the inner gerotor gear which has a combination rotating and orbiting movement. In this invention the universal drive has two main sections with a lost motion emergency device between the opposite ends.

Abstract: A steering system for an articulated vehicle having a pair of double acting steering cylinders and power steering means consisting of a pump and a hydrostatic steering unit to which the steering wheel of the vehicle is interconnected. Control means are disposed between the power steering means and the double acting cylinders for causing fluid to be directed from the power steering means to both of the first and second cylinders during rotation of the steering wheel at a first steering ratio when the pump is in operation, and at a second higher steering ratio when the pump is not in operation to permit manual steering of the vehicle.

Abstract: The present invention relates to a control unit for a vehicle powersteering mechanism comprising a housing having an inlet for connection to a source of fluid under pressure, an outlet for returning hydraulic fluid under pressure to said source, a pair of ports for connection to a hydraulic servomotor the movement of which controls the steering of the dirigible wheels of the vehicle, a hydraulic motor provided with a rotatable element and a follower element in operative combination with a distributor valve means provided with at least one displaceable body, said combination being operable on rotation of a control shaft connected thereto to divert hydraulic fluid flowing from said inlet through said housing to said outlet to one of said ports, and thus to its associated chamber of said servomotor, via said hydraulic motor, the hydraulic fluid being exhausted from the other chamber of the servomotor to said outlet, via said other port.

Abstract: The invention relates to a hydraulic control unit for a servomotor of the type used for vehicle steering systems. The unit has a control circuit with a power operated pump and a hand operated metering motor and an operating circuit with a power operated pump. The two circuits intersect upstream from the servomotor. A pressure comparison, throttling and proportioning valve is disposed between the outlets of the two pumps of the control and operating circuits. The proportioning valve is controlled by a differential pressure applied by the pumps and a spring which supplements the operating pump pressure. In the normal operating mode the proportioning valve allows a minor fractional flow of the pressurized fluid generated by the control pump to flow through the valve to the operating circuit.

Abstract: A fluid power assist type of vehicle steering system having a controlled servo motor assembly operated through a control circuit, and interconnected with the steering linkage, is provided with an auxiliary servo motor assembly through which pressure regulation is effected to prevent vibration otherwise amplified by feedback pressure signals. Differential pressure actuated pilot valves control the supply and return of pressurized fluid to and from the auxiliary servo motor assembly in response to differences between opposing pressures of the servo motor assemblies to regulate only the pressure chambers of the auxiliary servo motor assembly.

Abstract: Dual double acting servomotors hydraulically pressurized are provided wherein the pistons have shunt valve means actuatable at limit of movement of the pistons to shunt high pressure fluid at one side of the piston to the low pressure side of the piston then being exhausted. This results in relieving the stress otherwise effected against steering mechanism limit stops by continued application of high pressure feed to the pressurized chamber. The system encompasses steering control and shunt circuit valve means automatically actuated by differential pressures so as to direct pressure and exhaust flow selectively to and from the chambers of the respective cylinders from an engine driven pump and a manual metering pump for operating the steered wheels of heavy duty vehicles and which valve means effects bypassing of the engine driven pump pressure feed directly to one servomotor while feeding the combined pressures of that pump and the metering pump to the other.

Abstract: A hydrostatic servomechanism adapted to control the direction of vehicles and self-propelled machines. The mechanism has a power circuit with at least one servopump, at least one servomotor and at least one distributor, a control circuit with a measuring pump actuated by a command element as for example a steering wheel connected by means of control conduit branches to reset mechanisms and at least one feedback simulator with a flow meter in the power circuit and a controllable throttle means incorporated between the control branches of the control circuit. The feedback simulator forms a combined feedback simulator consisting of the flow meter and the throttle means controllable in steps, the throttle means being formed as a combination of several connected controllable throttle means.

Abstract: The invention relates to an assisted hydraulic control, especially for steering all types of vehicles, and comprising a double-acting receiver or hydraulic cylinder, the piston of which forms two chambers in the cylinder, the piston rod extending into one of the chambers only and having no counter-rod extending into the other chamber. The first chamber thus has a smaller effective section than the second chamber, and the resulting asymmetry of operation of the piston and therefore of the steering is compensated by an arrangement in which the distributor valve means of the control, which couples a return conduit to the second of two actuating conduits in a first working position, isolates the return conduit and connects together the second of two pilot conduits, the second actuating conduit and the first actuating conduit in the second working position.

Abstract: The invention is concerned with an improvement in a fluid controller for a power steering system which includes a housing having a fluid A for connection to the discharge side of a main fluid pump, an outlet for connection to the suction side of the main pump and a pair of ports for connection to the opposite sides of a dual acting hydraulic device such as a balanced cylinder of the power steering system for controlling the flow of pressurized fluid to the device. The controller includes a gear set which serves as a fluid meter or as a manual pump, depending upon the operativeness of the main fluid pump, and a spool valve shiftable axially to control the flow through the inlet, the gear set, the cylinder ports and the outlet. A control shaft is mounted for rotation on the housing responsive to movement of a steering wheel and is coupled to the spool valve for effecting axial shifting of the spool valve in response to rotation of the control shaft.

Abstract: A hydrostatic servomechanism adapted for controlling the direction of vehicles and selfpropelled machines. The servomechanism has a power circuit including a servopump, a distributor with reset mechanism, and a servomotor and a control circuit with a measuring pump connected through the control branches to the reset mechanism of the distributor and actuated by means of a command element, for example a vehicle steering wheel. The invention provides a simple reliable servomechanism with an artificial feedback simulator, non-sensitive to various harmful effects, providing a relatively stable and easily selectable gear ratio between the input and output parts of the servomechanism. The feedback simulator comprises a flow meter, a power circuit, and a controllable throttle means mechanically connected to the flow meter, the feedback simulator being incorporated between the control branches of the control circuit.

Abstract: The present invention relates to a control unit for a vehicle powersteering mechanism comprising a housing having an inlet for connection to a source of fluid under pressure, an outlet for returning hydraulic fluid under pressure to said source, a pair of ports for connection to a hydraulic servomotor the movement of which controls the steering of the dirigible wheels of the vehicle, a hydraulic motor provided with a rotatable element and a follower element in operative combination with a distributor valve means provided with at least one displaceable body, said combination being operable on rotation of a control shaft connected thereto to divert hydraulic fluid flowing from said inlet through said housing to said outlet to one of said ports, and thus to its associated chamber of said servomotor, via said hydraulic motor, the hydraulic fluid being exhausted from the other chamber of the servomotor to said outlet, via said other port.

Abstract: A steering system .Iadd.40 .Iaddend.for an articulated vehicle .Iadd.10 .Iaddend.having a pair of double acting steering cylinders .Iadd.24, 26 .Iaddend.and power steering means .Iadd.44 .Iaddend.consisting of a pump .Iadd.48 .Iaddend.and a hydrostatic steering unit .Iadd.50 .Iaddend.to which the steering wheel .Iadd.42 .Iaddend.of the vehicle is interconnected. Control means .Iadd.46 .Iaddend.are disposed between the power steering means .Iadd.44 .Iaddend.and the double acting cylinders .Iadd.24, 26 .Iaddend.for causing fluid to be directed from the power steering means .Iadd.44 .Iaddend.to both of the first and second cylinders .Iadd.24, 26 .Iaddend.during rotation of the steering wheel .Iadd.42 .Iaddend.at a first steering ratio when the pump .Iadd.48 .Iaddend.is in operation, and at a second higher steering ratio when the pump .Iadd.48 .Iaddend.is not in operation to permit manual steering of the vehicle .Iadd.10.