Abstract: A priority flow control valve for power circuits in hydraulic equipment, which is conventional in basic design, but makes use of an additional piston to impinge on the movable seat of a bias spring housed in a cylindrical chamber that connects with the constant flow passage to the priority outlet; the additional piston operates internally of a chamber having cross-sectional area greater than that of the chamber housing the spring, and is exposed to high pressure flow that can be routed into the chamber either from the priority outlet, or from the valve's main inlet, which will be connected to the high pressure line from the pump.

Abstract: A pressure equalizing valve comprises a valve body with a longitudinally disposed bore therein, and a spool disposed in the bore for longitudinal movement to regulate fluid communication from an inlet port to outlet ports in response to a pressure differential between first and second sense ports disposed on first and second end faces of the valve body.

Abstract: The invention relates to a priority valve for a hydraulic installation having a main circuit and an auxiliary circuit. The priority valve has a slide member which primarily has a controlled throttle for dividing the supply fluid between the main and auxiliary circuits in accordance with the priority demands of the main circuit. The priority valve has a flow path leading to the auxiliary circuit which has throttle elements in series which provide pressure drops in steps to minimize cavitation when there is a rapid flow of fluid in the auxiliary circuit.

Abstract: An automatic fluid flow regulator particularly adapted to maintain equilibrium within a cryogenic fluid system. The regulator includes a housing that has an input port and first and second output ports. A housing of the regulator contains a spool body having longitudinally extending expanding fluid channels provided on its outer periphery. The spool body cooperates with spaced flow restriction shoulders on which it is slidably disposed to bias the spool body by means of pressure differences exerted on the ends of the spool body by disturbances in the branches of the system to a position in which more fluid is supplied to one branch while less fluid is supplied to the other branch and the fluid system is brought into equilibrium.

Abstract: In a flow divider valve for pressure feed to a hydraulic circuit for auxiliary power steering and to a hydraulic circuit for a power take-off the interior of a hollow regulator piston receives pressure feed for distribution to the hydraulic circuits. For one such circuit, preferably the power take-off, flow passes via multiple bores and coacting flow control grooves of the regulator piston and a housing in which it reciprocates. Accordingly, a desired flow quantity and pressure advantages are achieved, in comparison with use of a single flow control bore which would require a larger piston traverse causing delays in pressure build-up as well as oscillations and strong flow pulses and energy loss.

Abstract: A hydraulic drive system for use with a vehicle power steering pump has a hydraulic motor connected in series with a power steering mechanism and a bypass line extending in bypassing relationship with the motor. A bypass valve is disposed in the bypass line to control the flow through the bypass line such that, when a steering force applied to a vehicle steering wheel is increased, the bypass flow is substantially in proportion to the steering force.

Abstract: A flow control device (12) for supplying first and second fluid distribution systems (16 and 18) with a constant percentage of fluid flowing from a single source of fluid (14). A housing (20) has a first bore (28) and a second bore (52) with a semi-cylindrical shaft (38) located in the first bore (28) to establish the relationship between fluid flow from an inlet orifice (32) and first and second outlet orifices (34 and 36). A shuttle valve (58-60) in the second bore (52) responds to the fluid flow from the first and second outlet orifices (34 and 36) and the respective back pressure to maintain the fluid flow through the first and second fluid distribution systems (16 and 18) in the same volume percentage as set by position of shaft (30) in the first bore (28). The shuttle valve (58-60) also provides a pressurizing function such that a minimum system pressure is required before any fluid flows to the first and second fluid distribution systems (16 and 18).

Abstract: In a priority control device the supply flow to the lower-ranking consumer is set by a flow control valve (pressure balance) whose control chamber subjected to the control pressure of the lower-ranking consumer can be relieved of pressure via a proportional valve. The proportional valve is adjusted in dependence upon the load pressure of the priority consumer so that the flow of fluid to the lower-ranking consumer is throttled by the pressure balance when the pressure difference at the priority consumer drops on increased volume flow requirement. The priority control device thus consists of two simply constructed power valves and a small-dimensioned pilot valve.

Abstract: A flow control valve comprises an orifice which is formed in a supply passage of hydraulic fluid, and a spool valve for feeding part of hydraulic fluid supplied through the supply passage to a branch passage in response to a pressure differential across the orifice. A switching valve which switches a fluid circuit is assembled with the flow control valve. The switching valve comprises drive means which is directly and mechanically coupled to the spool valve for forcibly causing a displacement of the spool valve to open the branch passage while closing the supply passage. Hydraulic fluid is normally supplied through the supply passage, but when the drive means is actuated, hydraulic fluid can be supplied only to the branch passage.

Abstract: An unloading valve utilized in an open center hydraulic system in conjunction with a conventional open center control valve having an open center passage and a dead end power passage; the unloading valve is supplied by a system pressure from a pump and divides the pump flow into two paths in a set proportion regardless of the amount of flow or pressure levels in either flow path, one flow path is directed to reservoir with the other flow path directed to the open center passage in the directional control valve while the dead end power passage of the control valve is separately provided with system pump pressure in a parallel path whereby only a portion of the pump discharge passes across the open center passage when the directional control valve is neutrally positioned.

Abstract: A pressure responsive flow divider valve for servo-powered steering devices comprises a flow control valve having three ports to divide the fluid flow delivered by a pump between a pair of partial volumes, one flowing to the steering valve and the other flowing to a further hydraulic load. When the steering device is not operated, the further load is primarily supplied with fluid, while the flow to the load is reduced, but the steering valve is fully supplied when the steering device is actuated. The valve comprises a valve member which is actuated in response to pressure to change the cross section of the throttle in the flow control valve so that the steering valve is supplied with a relatively small volume of fluid when the steering device is not operated, whereas the valve member is shifted by a pressure increase when the steering device is actuated to supply an increased fluid flow to the steering valve as required. The valve according to the invention allows to reduce energy to drive the pump.

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: Forms of a reaction control valve are disclosed utilizing various control signals with linear and rotary displacement structures to balance flow reaction forces and attain desired signal-responsive positioning. Different flow passage configurations attain different degrees of damping. An embodiment of the valve functions as a flow proportioner.

Abstract: A valve that directs flow from an inlet to at least two outlets, and which counterbalances flow induced forces that tend to restrict flow to one of its outlets. The valve has a valve chamber formed in a housing, and the inlet communicates fluid to the valve chamber. A valve member is movable in the valve chamber to communicate fluid from the inlet to the two outlets. The valve member has a land which fluid flows across as the fluid flows from the inlet to one of the outlets, and the fluid flowacross that land creates a force which acts on the valve member urging the valve member in a first direction in which flow across the land to the one outlet is restricted. Means communicates fluid pressure from the other outlet to the valve member to apply a force to the valve member that urges the valve member in a second direction that is opposite the first direction, to counterbalance the flow induced forces on the valve member.

Abstract: A two-speed, pilot-operated selector valve which directs hydraulic fluid to two motor elements with a common output shaft to obtain a high-torque, low-speed mode, or to one motor element, while recirculating the second element in a loop, to obtain a low-torque, high-speed mode. The spool has a built-in logic mechanism which, while shifting from one position to the other, prevents any momentary condition where a motor discharge port is blocked or a fluid path exists that bypasses both motor elements.

Abstract: An apparatus for controlling fluid flow to a steering motor and an auxiliary apparatus is capable of smoothly changing between conditions in which it directs relatively small and relatively large flows of fluid to the auxiliary apparatus. The apparatus includes a priority valve assembly having a valve member positioned in accordance with variations in the demand for steering fluid. A land on the valve member cooperates with a fixed valve surface to form a variable size orifice through which fluid flows to a steering controller. A second land on the valve member cooperates with a fixed valve surface to form a variable size main auxiliary flow control orifice through which all of the fluid flow to the auxiliary apparatus is directed during relatively low fluid flow rates to the auxiliary apparatus.

Abstract: A hydraulic flow divider and integrator for operating a plurality of hydraulic loads, in which a plurality of slide valves are each connected between a respective load and a source of pressurized fluid and subjected to hydraulic pressure bias from opposite ends by respective regulating spaces at the opposite ends of each slide valve, the slide valves each having an inlet communicating with the source, and a respective throttle connected between each inlet and a respective one of the regulating spaces of a respective slide valve and functioning to bias the respective slide valve in a valve opening direction, with hydraulic lines communicating between each one of the regulating spaces and the other regulating space of another of the slide valves, whereby a tendency to open one of the slide valves results in a reciprocal tendency to close the other slide valves, and another pressure source independent of the slide valves for pressurizing the one of the regulating spaces of at least one of the slide valves for lo

Abstract: A hydraulic differential locking device according the invention has a changeable range of sensitivity, the regulating slide valve being able to move even in the relieving connected position of the differential locking device, and is provided with springs ensuring the optionally selectable sensitivity of the differential locking device, the springs bearing on the two endfaces of the regulating slide valve and on the inner surface of the housing of the regulating slide valve.

Abstract: A priority valve is disclosed for controlling fluid flow between a power source and a secondary hydraulic function operated by the power source. The priority valve includes a housing having first and second bores formed therein. An inlet passage connects the power source to the first bore while an outlet passage connects the first bore to the hydraulic function. A priority function is also fluidly connected to the power source upstream of the priority valve. A valve spool is positioned in the first bore. The valve spool is movable between a first position blocking fluid flow from the first passage to the outlet passage and a second position permitting fluid flow therebetween. A pin is movably positioned in the second bore and has an enlarged end which extends into the first bore. Springs are present for urging the valve spool toward the first position and the pin toward the spool valve. A load signal passage connecting the priority function to the second end of the first bore.

Abstract: The present invention is a stabilizer for steering priority flow divider valves. The present invention prevents the variable displacement pump of the steering hydraulic system from destroking to zero displacement when the steering hydraulic demand rapidly varies from a high level to a low level of demand. The use of the present invention is especially advantageous in hydraulic systems which are close centered with pressure and flow compensation.

Abstract: A control valve assembly incorporates a piston and a flow control valve which are both biassed in the same direction against pressure in an hydraulic accumulator by first and second respective springs. Accumulator pressure in a control chamber also acts to urge the flow control valve in the same direction as it is biassed by the second spring and pressure from a pump acts to bias the flow control valve in the opposite direction. A pilot dump valve controlling communication between the chamber and an outlet connection is normally biassed into a closed position by a third spring. The dump valve is adapted to open at a cut-out pressure to dump pressure from the chamber, and the cut-out pressure is determined by the area of the seating of the dump valve over which the pressure in the chamber acts, and the force in the third spring. A cut-in pressure at which the dump valve closes is determined by the area of the piston and the force in the first spring.

Abstract: A priority valve is disclosed for controlling fluid flow between a power source and a priority function and secondary function operated by the power source. The priority valve includes a housing having first and second bores formed therein. An inlet passage connects the power source to the first bore while first and second outlet passages connect the first bore to the primary and secondary functions respectively. A valve spool is positioned in the first bore and is movable between a first position permitting fluid flow from the inlet passage to the first outlet passage while blocking fluid flow to the second outlet passage and a second position permitting fluid flow from the inlet passage to the second outlet passage while blocking fluid flow to the first outlet passage. A pin is movably positioned in the second bore and has an enlarged end which extends into the first bore. a load signal passage connects the priority function to the second end of the first bore.

Abstract: The present invention provides a proportional-flow electrohydraulic control which includes both an electrohydraulic valve (36) and an electronic control (382). The electronic control includes an offsetting circuit (622) and is effective to produce an effective driving voltage, for an electrical force-motor (52) of the electrohydraulic valve, that is pulse-width modulated and that is greater than a fixed proportionality to an input signal (410) by a manually adjustable offset voltage. The offset voltage may be adjusted to provide a null force that exactly balances a spring (129) which presses a valve spool (54) to an overlapped position; so that fluid flow is proportional to an input signal irrespective of the initial load of the spring. Or, the offset voltage may be adjusted to provide a basic flow voltage; and then the rate of fluid flow that is delivered by the valve is greater than a given proportionality to the input signal by a substantially constant rate of fluid flow.

Abstract: A control valve assembly incorporates a flow control valve, and a piston which are both biassed in the same direction against pressure in an hydraulic accumulator by first and second respective springs. Accumulator pressure in a control chamber also acts to urge the flow control valve in the same direction as it is biassed by the spring and pressure from a pump acts to bias the flow control valve in the opposite direction. A pilot dump valve controlling communication between the chamber and an outlet connection is normally biassed into a closed position by a third spring. The dump valve is adapted to open at a cut-out pressure to dump pressure from the chamber, and the cut-out pressure is determined by the area of the seating of the dump valve over which the pressure in the chamber acts, and the force in the third spring. A cut-in pressure at which the dump valve closes is determined by the area of the first piston and the force in the second spring.

Abstract: The present invention relates to a flow divider for carrying out a load-ipendent division of a stream of hydraulic fluid, comprising a basic body including an internal bore, a central main connection and two outer consumer connections leading to said internal bore, and further comprising two approximately coaxial control pistons which are displaceably guided in said internal bore and which are each provided with a flow orifice and with at least one radial control opening, said control pistons being adapted to be moved towards each other and away from each other to a limited extent via a coupling device connecting said pistons. In the case of known flow dividers the coupling device consists of interengaging hooks which are rigidly formed on the control pistons, said hooks producing, however, eccentric forces for the control pistons in said internal bore, and said forces impair the control characteristics and the operating behaviour of the flow divider.

Abstract: A fluid flow control system includes a priority valve which is controlled by a pressure differential applied across the valve, and which directs priority flow to a steering circuit and excess flow to an auxiliary circuit. The system insures that during steering, a relatively high pressure differential is required to shift the priority valve away from a priority steering position in which all fluid flow is delivered to the steering circuit. It also insures that when the flow to the steering circuit is sufficient to satisfy the steering demand, and the valve is also directing flow to the auxiliary circuit, a lower pressure differential is required to shift the valve in a direction for increasing the flow to the auxiliary circuit.

Abstract: A flow divider and combiner for delivering and receiving fluid under pressure to and from independent motors which are linked together for operation by an external force. The unit includes sliding flow control spools and relief valves operable within an orifice to provide a variable orifice for the control of flow with regard to pressure differentials. Through selection of the relief valve shapes and structures, the unit can be programmed for differential pressures existing between the inlet or outlet portions of the device and the differential pressures associated with the chambers connected to the independent motors versus the flow volume to the motors. This structure provides for a high degree of control at relatively low pressures and volume flow where such control is critical to proper operation and allows for less control and pressure loss at higher speed where such control is less critical to proper operation.

Abstract: A vehicle engine accessory drive system is disclosed including a hydraulic fan motor (M) and a power steering gear mechanism (SG) in series flow relationship. The system includes a variable displacement power steering pump assembly (P) which is the sole source of fluid for the system, and includes a variable displacement pumping element (PE) and a displacement control valve (CV). The displacement control valve includes a pilot valve (35) which is responsive to the demand for cooling to vary the fluid pressure in a signal chamber (63). The displacement control valve is operable to communicate a control fluid pressure to a stroking cylinder (SC) to control the fluid delivery rate of the pumping element. At a first relatively lower temperature, the displacement control valve maintains the fluid delivery rate of the pumping element at Z, and at a second relatively higher temperature, to maintain the fluid delivery rate at X.

Abstract: A hydraulic system for a vehicle having an open-center hydraulic brake booster powered by an engine-driven single rotary pump with an unloader valve into which is incorporated a bypass valve to enable a fluid flow to bypass the unloader valve into the brake booster. The invention contemplates the use of the bypass valve for such purpose as pressurizing the fluid circuit upstream of the bypass valve for storaging fluid in a fluid storage member under pressure in case of rest position of the booster for actuating the booster when the pump failed.

Abstract: A hydraulic system is disclosed for use in an automotive vehicle including an engine, a power steering gear, and a brake booster. The system includes a single engine driven pump in fluid communication with first and second fluid flow control means. The first fluid flow control means responsive to fluid inputs for discharging a small or large predetermined amount of hydraulic fluid to control the operation of the power steering gear. The second fluid flow control means supplies a constant amount of hydraulic fluid to control the operation of the brake booster.

Abstract: The invention relates to hydraulic flow dividing and integrating equipment, having a regulating slide valve in its flow path and calibrated throttlings in an admission channel of the flow path. The calibrated throttlings are adjustable as a function of entering liquid flow. Mobile rings are arranged on the regulating slide valve. With these simple technical arrangements, the field of application of hydraulic systems, e.g. for gear synchronization, is considerably enlarged.

Abstract: A flow divider valve assembly for dividing a flow of fluid between a priority flow device, such as a power steering system, and an excess flow device, such as an auxiliary mechanism. The flow divider valve assembly comprises a valve body defining an inlet port to be connected to a source of fluid under pressure, a priority flow outlet port, an excess flow outlet port and a valve bore interconnecting the ports, and a valve spool axially movable within the valve bore, the valve spool having formed therein an axial bore for permitting a constant communication between the inlet port and the priority flow outlet port. A first restrictor is disposed between the inlet port and the priority flow outlet port and a second restrictor is disposed between the inlet port and the excess flow outlet port. Restriction rate of the first restrictor is made larger than that of the first restrictor.

Abstract: The device comprises a cylinder-piston unit B, the chambers B1 and B2 whereof are connected with the delivery of control pump A and with the control member K2 of utilizer K1. The movable part 14 of the said cylinder-piston unit B is subjected to the influence of spring means 16 and presents a calibrated opening D, said opening being co-axial with the said cylinder-piston unit, while means 20 and 22 sensitive to the pressure building up in chamber B2 of the cylinder-piston unit B control the communication between the said chamber B2 and discharge A1. Said means 20 and 22 are combined with adjustable members 24, 28, 36 which counteract the action of the pressure building up in chamber B2 of the cylinder-piston unit B. It is thus possible to fill the actuating group K2 within a pre-determined period of time.

Abstract: The invention relates to hydraulic steering apparatus of the type having valve gear for selectively directing pressurized fluid to and from opposite sides of a servomotor connected to vehicle wheels to be steered. This type of steering apparatus only requires pressurized fluid when actuated and may provide an auxiliary circuit with pressured fluid at times when it is not being actuated. Priority valves give priority to the steering apparatus. During extended intervals when pressured fluid is supplied to an auxiliary circuit, parts of the steering apparatus are subjected to substantial cooling. Then when the priority valve diverts hot pressurized fluid from the auxiliary circuit to the cooled steering apparatus the temperature differential causes an adverse effect on the steering apparatus by creating a tendency for binding of parts due to the unequal expansion of valve sleeves.

Abstract: The disclosed valve device includes first, second and third user ports. A pressure accumulator connects with the first user port. With the accumulator fully charged, a pressure port connected to a pump communicates with the second user port. With the accumulator evacuated, the pressure port communicates with the first user port. In the event of a fluid demand at the third user port, the pressure port will be connected to the third user via a control valve. The control valve is a non-return valve in a channel connecting the first user port to the third user port, which opens under influence of a pressure in the first user port.

Abstract: A system is disclosed for controlling the flow of fluid from a pair of pumps (15,15') to a steering system (11) and a pair of auxiliary load circuits (13,13'). The steering system includes valving (43) defining a variable flow control orifice (45), and the steering system normally operates with a pressure differential X across the variable orifice, and provides load pressure signals (47,49,49',53,53') representative of demand for fluid by the steering system. Fluid flow from the pumps is controlled by a pair of priority flow control valves (21,21') including a pair of valve members (27,27') each of which is biased by a spring (29,29') toward a position permitting flow to the steering system. The spring (29) exerts a biasing force equivalent to the pressure differential X while the spring (29') exerts a biasing force equivalent to a pressure differential Y, which is less than X.

Abstract: For work vehicles, for example, cold weather can be a problem. Disengaging the vehicle clutch (26) aids starting by reducing engine loads during starting. Where the clutch (26) is hydraulically actuated, it can be disengaged by keeping fluid pressures below required engagement pressure when supplying other elements common to the clutch hydraulic circuit. Apparatus is provided which during starting directs fluid to, for example, pump drive bearings (20) at less than clutch engagement pressure. An input signal to the apparatus from the vehicle operator after engine start-up then builds pressure to activate the clutch (26) while continuing to supply the pump drive bearings (20) for lubrication. Upon a preselected fluid flow to the apparatus, such as at engine shutdown, the apparatus automatically returns to the condition at which available pressure levels are less than required for clutch engagement.

Abstract: The valve device disclosed includes first, second and third user ports. A pressure accumulator connects with the first user port. With the accumulator fully charged, a pressure port connected to a pump communicates with the second user port. With the accumulator evacuated, the pressure port communicates with the first user port. In the event of a fluid demand at the third user port connected to a closed-center user component, the pressure port will be connected to the third user port via a control valve.

Abstract: A fluid flow equalizing valve has two coupled valve devices for controlling flow to or from a common connection to respective ones of a pair of actuators. Control elements of the valve devices are responsive to intermediate pressures in flow paths to or from the actuators, and move in unison to reduce any difference in the intermediate pressures, and thereby to maintain the flows to or from the respective actuators substantially equal.

Abstract: In an hydraulic system an unloader valve is located in a line between a pump and an hydraulic accumulator. The unloader valve is operative to prevent the accumulator from being overcharged and to allow the pump to re-charge the accumulator should the pressure stored therein fall below a desired minimum value. The unloader valve incorporates a control valve comprising a spool and a pressure responsive slave which is operated by fluid pressure under the control of the control valve. A single spring acts to bias the spool into a first position against pressure in a control chamber into which fluid is pumped through a first one-way inlet valve. A second one-way exhaust valve located between the first one-way valve and an exhaust port can be opened by the slave to unload the pump.

Abstract: The present invention is a pressure limiter for a hydraulic booster. The pressure limiter adjusts and limits the pressure generated between a pumping means and a restricting gap in a gain valve by limiting the size of the gap in response to sensed system pressure. A pressure limiter piston responds to system pressure to act against a gain valve piston and control the size of the gain valve gap.

Abstract: A priority flow divider is disclosed for dividing hydraulic fluid flow between a steering circuit and an auxiliary circuit thereby providing better efficiency and greater productivity for the auxiliary circuit. The priority flow divider includes a cylindrical housing having a slidable spool valve therein, and the housing further includes an inlet port connected to the steering pump in the steering circuit, a discharge port connected to the steering valve, in the steering circuit, and a discharge port connected to the auxiliary hydraulic circuit. The spool valve has enlarged cylindrical portions which are connected by recessed connecting portions of a reduced diameter.

Abstract: The present invention is a gain valve for a hydraulic booster which allows transition from a manual braking mode to a power assist braking mode without the control called for in the manual mode immediately applied when the power assist function begins to operate. This is accomplished by a bypass passage through the gain valve piston which prevents a pressure increase in the hydraulic booster for power assisted braking. The bypass passage automatically opens and resets in response to system pressures.

Abstract: There is provided a proportioning device for connection to a main line carrying a pressurized fluid, for the purpose of introducing into or drawing from the main line a fluid at a rate standing in a substantially constant proportion to the flow rate of the main line. The device comprises a housing, at least one opening of which is connected to the main line and another opening of which is connected to the proportioning branch line. The device comprises a valve arranged in the housing and capable of closing the passage of the fluid into and from the proportioning branch line.

Abstract: A flow control valve assembly for controlling first and second reversible fluid motors for series or parallel operation has a direction control secton and a torque control section provided in a single valve body. The valve body has first, second, and third supply ports selectively pressurizeable by the direction control section and connected to a torque control bore in the torque control section. First and third function passages extend from the torque control bore and are connectible to the first fluid motor, and second and fourth function passages extend therefrom and are connectible to the second fluid motor. A grooved, torque control spool is disposed in the torque control bore for sliding from a series operating position wherein the grooves connect the first port to the first function passage, the second function passage to the third function passage, and the fourth function passage to the second and third ports.

Abstract: A cross-flow controlling valve for a hydropneumatic vehicle suspension has a casing formed with three ports of which two communicate with longitudinally terminal portions of a bore in the casing. A piston is freely slidable in the bore between two terminal positions. Longitudinally spaced shoulder portions of the bore bound a transversely open, longitudinal groove in the piston which is longer than the intermediate portion of the casing bore connecting the terminal bore portions. Each shoulder portion is dimensioned to bound a throttling gap connecting the groove with one of the terminal bore portions when the shoulder portion is received in the intermediate bore portion. The groove in the piston permanently communicates with the third casing port.

Abstract: The valve includes a control piston axially slidable in a cylindrical bore which controls the cross-sectional area of an orifice of a connection between the cylindrical bore communicating with a pressure port and a user port. The control piston is acted on by a spring and a pressure which is reduced relative to the pressure at the pressure port. A cushioning arrangement acting on the control piston avoids occurrence of pressure surges affecting the control piston behavior.

Abstract: A flow divider valve assembly and a power assisted steering system therewith. A spool (1) is axially slidable in a spool cylinder (2) within which it is biased (23, 24) to a neutral condition in which two control ports (13, 16) are open. A first of the control ports (13) is in a first fluid line which extends from an inlet port (8) by way of a first auxilliary chamber (11) to an outlet port (15) and the second control port (16) is in a second fluid line which extends from the inlet port (8) by way of a second auxilliary chamber (12) to a second outlet port (18). The outlet ports (15, 18) can be connected to opposite sides of a power assisting ram in a steering system. Communicating with the first fluid line downstream of the first control port (13) is a first primary chamber (19) formed on one side of the spool (1) and communicating with the second fluid line downstream of the second control port (16) is a second primary chamber (21) formed on the opposite side of the spool (1).

Abstract: The steering system comprises at least one double-acting fluid cylinder, a directional control valve connected to the cylinder for alternately extending and retracting the cylinder and a hand metering unit for communicating a fluid steering signal to the directional control valve whereby an engine-driven pump is adapted to communicate pressurized fluid to the cylinder for steering purposes. A variable flow control valve is interconnected between the pump and the hand metering unit for communicating a variable fluid flow to the hand metering unit in proportion to the speed of the pump to vary the fluid steering signal whereby an operator can sense the speed of the pump. In the preferred embodiment of this invention, the variable flow control valve comprises a pair of spring-biased, reciprocal members which sense a differential pressure across the valve to control fluid flow through an outlet which is adapted to be connected to the hand metering unit.

Abstract: A valve for dividing a fluid flow at an inlet port subject to variable flow volume into two fluid flows at first and second outlet ports having a substantially constant ratio of flow volumes, including first and second flow passages from the inlet port to the first and second outlet ports. Each flow passage includes a variable orifice the openings of which are varied by fluid pressures proportional to the fluid pressure acting on opposite ends of a spool valve. A normally closed valve is provided for permitting an increase in fluid flow through the first outlet port when the inlet fluid flow exceeds a predetermined pressure.