Abstract: A steering system for a motor vehicle comprising a steering linkage, a steering drive, a gearbox transmitting a driving movement of the steering drive to the steering linkage, and a multi-piece housing that at least partially surrounds the steering linkage, the steering drive and/or the gearbox, having a drainage groove formed in a first contact surface of a first housing part of the multi-piece housing, the first contact surface being seated against a mating second contact surface of a second housing part of the multi-piece housing.

Abstract: An electrohydraulic actuation system in which the quantity of fluid being fed to hydraulic actuators under higher load pressure among those of a plurality of electrohydraulic actuators can be prevented from becoming deficient. In the electrohydraulic actuation system (100), a selection valve (141), a two-position valve (142), a spring (143) and a hydraulic cylinder (144) for altering delivery alter delivery of the working oil of a variable delivery hydraulic pump (111) based on the maximum pressure of the working oil being fed to hydraulic motors (122, 132) and the delivery pressure of working pump (111), and pressure gauges (145, 146, 147, 148, 149) and a computer (not shown) alter the rotatim speeds of motors (123, 133) at a substantially same rate for them.

Abstract: The invention relates to an actuator cylinder, which is intended to be operated using a control valve controlled by an operating lever. The actuator cylinder includes a cylinder barrel, a piston, and a rod, which extends outside the cylinder barrel. A detector element is fitted in connection with the rod, its angle of rotation corresponding to the current position of the piston. The control valve includes a rotatably supported slide construction, to which the detector element is connected in order to rotate the slide construction to a free-circulation position, when the piston is in a position according to the operating lever. The control valve also includes connections, between which a through-flow channel is arranged. The slide construction additionally includes a component shutting off the through-flow channel.

Abstract: There is provided an electrohydraulic motor that has a spool valve 110 for switching from each of drive positions (111, 112), in each of which a corresponding one of a main oil passage 230 and a return oil passage 240 is connected to a hydraulic actuator 130, to a neutral position, in which the hydraulic actuator 130 and each of the main oil passage 230 and the return oil passage 240 are disconnected, and vice versa. There is also provided a connection switch valve 140, which is connected to the main oil passage 230 and the return oil passage 240, for changing the connection between the main oil passage 230 and the return oil passage 240 in the neutral position 113. In response to an operation of the spool valve 110, the connection switch valve 140 connects the main oil passage 230 to the return oil passage 240 in the neutral position 113 and also disconnects the main oil passage 230 from the return oil passage 240 in the drive positions (111, 112).

Abstract: An electrically powered steering device comprises a ball screw mechanism for transmitting a steering force from a steering wheel to steerable vehicle wheels. The ball screw mechanism includes a rotary nut 11 having a nut body 11a in which a circulating passage 15 is formed so as to extend axially thereof, and end caps 14a and 14b secured respectively to opposite ends of the nut body 11a. Each of the end caps 14a and 14b has defined therein respective guideways 17a and 17b for balls 13 that communicate opposite ends of the circulating tunnel 14 with a ball rolling passage 12. The end caps 14a and 14b and the nut body 11a are made of a sintered alloy. The nut body 11a has an outer periphery of one end thereof that is axially progressively reduced in diameter to define a tapered surface.

Abstract: An electro-hydraulic servomotor includes: an electric motor (41) which rotates a drive shaft (51) in response to an inputted signal; a hydraulic motor (60) which rotates an output shaft (61) using hydraulic pressure of operation oil; a first geared shaft (53) rotatable along with the output shaft (61); a second geared shaft (52) threadingly engaged with the drive shaft (51) and meshed with the first geared shaft (53); and a spool (71) axially movable along with the second geared shaft (52) depending on a rotational difference between the drive shaft (51) and the first geared shaft (53), to control supply and discharge of the operation oil to and from the hydraulic motor. (60).

Abstract: A hydraulic drive unit has a tracking regulator valve (19) for controlling a servo drive (18) of a main control valve (16), where the main control valve controls flow to a hydraulic motor (11). The tracking regulator valve is controlled by an actuating element (42), which is controlled by a comparison of a nominal position value, set by an electric motor (36), and an actual position valve, generated by a mechanical feedback (53) connected to the hydraulic motor. The main control valve includes a slide valve piston (87), which forms a housing for the tracking regulator valve, which has two piston slide valve elements (39, 41). The slide valve piston (87) of the main control valve (16) has an axial through-bore (122) through which passes the actuating element.

Abstract: An actuator system having a motor that drives a pneumatic spool valve to a known position based upon the number of step commands delivered to it. Valve ports or passages uncovered by the net position difference between the spool valve and a piston create gas flow to or from a control chamber. This gas flow causes a pressure differential across the face of the piston, inducing the piston to follow the spool valve. In this two-stage system, the piston acts as a force amplifier so that large forces and/or inertias may be actuated by positioning the motor. During steady state conditions, the piston achieves the same position as the spool valve is. Proportional control and very accurate positioning of the piston are provided without active position or position rate feedback control.

Abstract: A power-assisted steering device having a piston located in a casing and driven by a rotational input from an input shaft. The piston has a sealing section for separating a first chamber from a second chamber and a transmission section. The transmission section having a U-shaped profile formed by two branches which are coplanar with the main axis of the casing. The branches form racks and mesh at respective geometric sites with toothed sectors which are integral with one another and an output shaft. A sleeve located in the U-shaped profile and connected to the piston prevents relative rotation of the piston and sleeve with respect to the main axis of the input shaft while allowing some relative radial translations with respect to the input shaft as the piston is moved in response to a pressure difference in fluids supplied to the first and second chambers to provide assistance in rotating the output shaft in response to an input applied to the input shaft.

Abstract: A roller-contact bearing device with a reduced clearance for a power-assisted steering system having a first roller-contact bearing for absorbing axial forces exerted on a steering shaft and a second roller-contact bearing for transmitting the axial forces to a casing. The second roller-contact bearing is urged toward shaft by an spring disc to oppose the axial forces being applied to the shaft.

Abstract: A hydraulic master cylinder (1) comprises a body (2) in which conventional output chambers (5,6) are defined. In use, the output chambers are pressurized by a piston (4) which is moved by a combination of mechanical input force applied to an input member (8) and hydraulic pressure within a servo chamber (13) located to the rear of the piston (4). Connection of the servo chamber (13) to a pressure source is controlled by poppet valves (16, 17) which are opened as necessary by ribs (23, 24) of a sleeve (22) mounted on imput member (8). The sleeve (22) is coupled to the piston (4) but free to rotate relative to the input member (8) and is coupled to the input member by means of a helical groove and ball arrangement such that movement of the input member (8) towards the piston (4) causes rotation of the sleeve (22) to open the inlet valve (17), and movement of the input member ( 8) away from the piston (4) causes opposite rotation of the sleeve (22) to close the input valve (17) and open the outlet valve (18).

Abstract: A hydraulic control device comprises a valve (4) which can be moved inside a casing (1) and a stop for opening the valve at one point, the position of which may be set. The stop (6) slides in an axial housing (7) under the effect of a spring (8) and a stop screw (9). The opening position of the valve (4) may be easily set from outside the casing (1).

Abstract: A device for limiting a working stroke of a hydraulic cylinder has a working cylinder and a working piston comprising a hollow piston rod connected to its top portion. A pressure reservoir is connected to a first working chamber for constantly supplying a pressure medium thereto, and a pressure source is connected via an inlet line to a second working chamber for supplying a pressure medium thereto. A shut-off valve comprises a push piston and a return spring for holding the push piston in its closed position. A drag link is slidably connected inside the push piston and extends through the working piston into the interior of the hollow piston rod. One end of the drag link has a first abutment that comes into contact with the working piston before the working piston reaches its end position.

Abstract: A linear drive comprises a hydraulic unit (1), a control valve (5) and an actuating drive (9) with an actuating member (7). These elements are interconnected by means of two inertia drive starters (4, 8), which results in a mechanically-induced return movement. The movement of the piston rod (15) of the hydraulic unit (1) is controlled in the actuating drive (9) by means of active elements (10, 35, 56) moved translationally in the direction of the longitudinal axis of the linear drive. The active elements (10, 35) and the actuating member (7) are connected without play in the axial direction but can counterrotate with respect to each other by means of a bearing (38). A lever (13) is arranged on the actuating member (7) and can be rotated together with the actuating member (7) about the axis (60). The lever (13) cooperates with a stop element (14) which can be adjusted by a rack (50) and which limits the rotation of the lever (13).

Abstract: A fluid-powered servo actuator having a body, an annular piston, and a shaft extending co-axially therewithin. The shaft has an interior chamber located within the body with two fluid channels extending to the chamber in which the piston is mounted. One channel communicates with each side of the piston. A valve spool is positioned in the shaft chamber, and a cam follower or threads are used to longitudinally move the valve spool therewithin in response to its selected rotation. The valve spool has a pair of valve lands which, when in a neutral position, close the two channels. When the valve spool is moved longitudinally, pressurized fluid is communicated with one or the other of the channels to cause the piston to move longitudinally. Splines or rollers convert the longitudinal movement of the piston into rotational movement of the shaft.

Abstract: A servo system includes a tubular drive shaft journalled in a housing. A screw is engaged threadably with a nut which is fixed in the drive shaft. A driven body is secured to an end of the screw so that the screw can effect a rectilinear movement with the driven body but cannot rotate. A motor can rotate the drive shaft in an infinite angle through a gearing so that the drive shaft can move in a first direction continuously. Then, an end of a fork is rotated by an abuttment element which is sleeved on the drive shaft. At this time, the other end of the fork activates a hydromechanical servo, and hence a hydraulic driving unit, to move the drive body in a second direction which is equal and a opposite the first direction. After which, the drive shaft is moved back to the original position by the driven body. The driven body is therefore moved a predetermined distance.

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

Abstract: A power steering system for use in a motor has a pair of reactive pressure chambers in which the opposite ends of a valve spool are exposed, one of the reactive pressure chambers communicating with one fluid-pressure chamber in a reciprocable fluid-pressure cylinder assembly through a first orifice, the other reactive pressure chamber communicating with both fluid-pressure chambers in the cylinder assembly through second and third orifices, respectively. The first, second and third orifices are the first and second orifices are defined in the valve spool. A third passage define by a space between the spool and the valve cylinder communicates the first and third orifices.

Abstract: The servo control system that is provided particularly as a power steering system for motor vehicles has two shaft parts that can be rotated with respect to one another against a spring force. An element slides as a function of the relative rotation, said element, in turn, adjusting a control slide of a servo valve arranged with a stationary housing. Correspondingly, a piston of a motor operator is acted upon by different pressures.

Abstract: A fluidic power-assisted setting device has a setting motor having an output torque; a threaded spindle supported for rotation; a spindle nut threadedly mounted on the spindle for linear displacement; a setting member attached to the spindle nut for linear travel therewith; a gearing for transmitting the output torque of the setting motor to the spindle; a signalling device coupled to the gearing for generating an output signal when the linear force derived from the output torque of the setting motor is insufficient to overcome an external force opposing linear displacement of the setting member; and a fluidic power device including a hydraulic motor connected to the setting member for applying thereto a linear force to overcome the external force; and a hydraulic control valve hydraulically connecting the hydraulic motor with pressurized hydraulic fluid as a function of the output signal of the signalling device for causing the hydraulic motor to generate a force applied to the setting member for overcoming

Abstract: A rotary drive fourway spool valve with rotary feedback includes a spool and a seat sleeve both rotatable within and the spool axially slidable in the valve body and connected by a straight screw thrust. Belleville springs center the sleeve azimuthically relative to the spool.

Abstract: A power assisted steering gear having a movement transmitting drive member connected to and rotatable with the steering unit, one portion of which that determines the axis of rotation is formed by the connection between the steering nut and drive member. Another portion is formed by a ball pivot fitting into the nest of a double acting piston and a further ball pivot fitting into the nest of an axial slide valve of the piston which is set outside the axis of rotation.

Abstract: A compact power steering device is provided wherein the power steering valving is actuated by axial movement of a pinion having helical teeth engaging a rack in a steering housing. The valving utilizes head and seat valves with valve heads and coacting valve seats which are actuated on axes parallel to the pinion axis within the housing and requiring no more than the overall distance occupied by axial movement of the pinion as effected by rotation of a steering wheel during steering. Opposed springs effect a centered position for the pinion in neutral position of the valving for straight ahead steering. Thus, a centering spring is dominant and limited in movement to fix the valving as biased by other springs to a precise neutral position.

Abstract: A hydraulic pivot drive comprising a rotary-piston hydraulic cylinder and control device for maintaining the pressure difference between pressure chambers defined by the rotary vane and at least one radial wall of the cylinder housing required for maintaining a defined relative rotary position between the vane and the housing of the rotary piston hydraulic cylinder. The control a follow-up control valve, wherein the actual condition relative to the pivot angle is fed back via a measuring spindle coupled with the rotating part of the rotary piston hydraulic cylinder and the desired value is pre-set by rotation of a spindle nut engaging the spindle, an actuating member arranged for axial displacement together with the spindle nut and for actuating pairs of seat valves for enabling alternative connection of the at least two pressure chambers of the rotary-piston hydraulic cylinder with a system to obtain the desired rotation.

Abstract: A power drive unit for thrust reverser structure includes a reversible motor in a hydraulic circuit and has normal stow and deploy cycles of operation. In a deploy cycle, the load on the motor is aiding and, in the event the deploy cycle is inadvertent, the load on the motor can be substantially higher. In order to avoid this increased loading on the motor in an inadvertent deploy cycle, the hydraulic circuit has an auto-restow valve which senses the high aiding load in the event of an inadvertent deploy operation and changes the operation of the power drive unit to operate the motor in a stow cycle to prevent continued high loading on the motor and thrust reverser structure.

Abstract: An integral power steering gear assembly includes a piston and cylinder combination having greater output efficiency through improved fluid balancing and cushioning of the piston at its ends. The improved cushioning utilizes oil capillary slots in lieu of previously proposed epoxy resin strips. The slots may be fed with high pressure fluid filled by feed grooves along the sides of the piston adjacent the output rack. The slots are designed to have a shallow depth, preferably 0.001 inch - 0.0025 inch, which is sufficient to provide for high capillary attraction of the oil molecules to the slot. The trapped oil molecules prevent slip stick action, that is molecular interaction between the piston and cylinder wall, but at the same time, the oil molecules remain trapped or isolated within the walls of the slot thereby minimizing leakage from the slot.

Abstract: A control valve in a power boost steering system uses hydraulic power for wheel straightening after a steering operation wherein a valve spool is reciprocal with a worm shaft which has an end threadedly carrying a non-rotative but slidable collar to compress springs as the worm shaft is rotated by virtue of being keyed against rotation. Thus, rotation of the worm shaft can actuate the collar axially in either direction against oppositely disposed compression springs depending on direction of steering rotation of the worm shaft by a manually operated steering spindle. When manual steering force on the steering spindle is released, the compressed spring expands to axially move the worm shaft and thus the valve spool through a neutral position which exhausts the cylinder chambers. However, the continued expansion of the compressed spring moves the valve spool to a position whereat pressure flow and exhaust of the cylinder chambers is reversed from the original steering direction.

Abstract: An auxiliary fluid power steering device having a servomotor (8) and a control valve (13) in a common steering gear housing (1). In order to relieve the control valve of axial pressure forces, the valve body (14) of the control valve has four surfaces (24, 25, 26, 27) of equal area respectively exposed exclusively to fluid in the inlet port (22), in the outlet port (23), in one of the servomotor pressure chambers (9) adjacent the control valve and in the other pressure chamber (10) of the servomotor.

Abstract: A power steering system for motor vehicles, wherein a steering nut, connected to a steering worm in such a manner that the steering worm is driven thereby, is rotatably and axially non-displacably mounted in a working piston and is also provided with a control arm passing through both a radial recess in a working piston and a radial opening in a cylinder housing that receives the working piston. An end of the control arm which is radially outermost with respect to an axis of the piston actuates a spool valve for adjusting the working pressure. Two corresponding followers are provided for defining the end stroke positions of the working piston. The followers are mutually engagable to lower or shut off a working pressure in the system. One of the followers is disposed opposite the working piston relative to the piston axis and the other is located opposite the cylinder housing relative to the cylinder axis with a zero motion.

Abstract: A power steering system has a servomotor flow control valve with means for automatically returning the vehicle to straight ahead position by hydraulic power. This is accomplished in a construction utilizing a piston valve linked by a cam mechanism to movement of a servomotor piston in such manner that, responsive to movement of the servomotor piston, and upon return of the piston valve to a neutral position a brief overtravel beyond neutral position occurs which reversely pressurizes the servomotor to straighten the wheel direction after a turn.

Abstract: A servomechanism in which the mutual angular position of a threaded spindle relative to a tap is adjustable by a stepper motor wherein the unit of the threaded spindle and tap is connected directly or indirectly with a hydraulic working unit, the servomechanism includes a ball bearing arranged between the spindle and the tap. Consequently, by actuating the stepper motor to which the tap is connected via a coupling, the tap being rotated and moved in axial direction relative to the spindle, thereby actuating a switching mechanism connected to the working unit by which the spindle is caused to rotate. Accordingly, the relative axial movement between the spindle and the tap is compensated and the working unit is in a different position.

Abstract: A control valve arrangement for a servo-steering mechanism which includes a valve control member responsive to arbitrary steering motions of a steering wheel by executing relative movement with respect to a valve housing. The control member is subdivided into two coupling elements movable relative to each other, which coupling elements are mutually resiliently supported. One of the coupling elements is, in a geared manner, connected to the steering wheel with the other coupling element being provided with four control edges cooperating with corresponding control edges of a valve housing. Two of the control edges control a throttling of two pressure medium connections of one working pressure chamber of the servo-steering mechanism with the other two control edges controlling a throttling of two pressure medium connections of a second working pressure chamber of the servo-steering mechanism.

Abstract: An integral power steering gear assembly includes a piston and cylinder combination having greater output efficiency through improved fluid balancing and cushioning of the piston at its ends. The improved cushioning utilizes oil capillary slots in lieu of previously proposed epoxy resin strips. The slots may be fed with high pressure fluid filled by feed grooves along the sides of the piston adjacent the output rack. The slots are designed to have a shallow depth, preferably 0.001 inch-0.0025 inch, which is sufficient to provide for high capillary attraction of the oil molecules to the slot. The trapped oil molecules prevent slip stick action, that is molecular interaction between the piston and cylinder wall, but at the same time, the oil molecules remain trapped or isolated within the walls of the slot thereby minimizing leakage from the slot. The operating oil is delivered with higher efficiency in the power steering unit by a bifurcated oil delivery passage communicating with the inlet slot of the piston.

Abstract: The present servomotor has a working piston in a piston cylinder. The worg piston is connected to a spindle having a relatively high pitch. The spindle is attached at one end thereof to a control disk system comprising three control disks. The two outer control disks are rigidly connected to the spindle, and the central control disk is connected to a digital stepping motor. The central disk is arranged between the two outer control disks so that the central disk may rotate substantially free of play, whereby the rated position of a stepping drive motor corresponds precisely to the actual position of a linear output member, such as a piston rod.

Abstract: A steering control valve and worm nut centering device for a power steering booster mechanism control valve is provided comprising a flexure rod carried either by the double-acting piston member or the worm nut member and extending between those members or into the valve spool. The overall construction is conventional and well known, the particular feature of the invention being a flexure rod which is adjustable translationally or rotatively, in various modifications, to center the valve spool of the control valve and to center the worm nut. The flexure rod can be predetermined as to length, taper, alloy, and other design factors so as to flex to give a desired increase in road resistance feel substantially over and above that afforded by the usual size of reaction chambers and centering spring conventionally associated with the valve spool.

Abstract: A power drive unit for operation of structure in opposite directions, such as aircraft structure and, particularly, thrust reverser structure of an aircraft engine operable between stow and deploy positions, including, a bi-directional hydraulic motor having a variably positionable wobbler for controlling displacement of the motor. Control structure includes a valve for causing fluid flow through the motor in either of two directions, a control cylinder and piston connected to the wobbler for setting the motor at either minimum or maximum displacement conditions or at any condition therebetween, a servo valve operable for setting the position of the piston in the control cylinder, and a differential area piston operatively connected to the servo valve for positioning thereof and responsive to the pressure drop across the motor in either direction of operation thereof to set the motor displacement at the least value possible for the load condition on the motor.

Abstract: Disclosed is a hydraulic servomechanism wherein the motion of a driven element is synchronized with the motion of a command element by detecting any phase difference between the movement of the driven element and that of the command element, controlling the flow rate of a hydraulic fluid being fed to the driven element with a directional and flow control valve in proportion to the detected amount of phase difference and also controlling the flow rate of the hydraulic fluid being fed to the hydraulic servomechanism with a pressure compensation valve in proportion to the variation in the load exerted on the driven element.

Abstract: A pilot operated stepping valve where an electrical pulse motor drives a pilot valve spool which controls the flow of hydraulic fluid driving a main valve spool which actuates a hydraulic motor or actuator. The main valve spool follows the pilot spool and is hence sensitive to the pulses received by the pulse motor.

Abstract: Fluidic amplifier, particularly a hydraulic linear amplifier for converting a low-energy rotary movement of a control member into a linear setting movement of the piston rod of an operating piston, wherein: the control member is connected with a threaded spindle whose free end extends into an axial bore in the piston rod of the operating piston and mates with a spindle nut provided in the axial bore; the pressure fluid for charging the operating piston to produce the setting movement of the piston rod is controllable by means of an axial deflection of the control piston of a control valve, which deflection is effected by the control member and the threading of the threaded spindle into the spindle nut, and this setting movement causes the control piston to be repositioned to its starting position. A protective device is provided within the amplifier for the automatic separation of the mechanical connection between the operating piston and the control piston during a malfunction.

Abstract: A power steering mechanism comprises distributing means for communicating fluid pressure to the compartments of a fluid motor associated with the steering linkage of the vehicle. Each distributing means comprises a ball valve member disposed in a chamber of a housing. The valve member is urged towards a first valve seat defined in a low pressure supply passage, by means of spring means, and towards a second valve seat defined in a high pressure supply passage by means of an extension of an actuating piston, said extension extending through the low pressure passage. The piston is moved by way of a sleeve disposed intermediate between the input and output members and connected thereto by means of a spline and screw arrangement. In response to a torque applied to the input member, the sleeve is allowed to move axially for displacing the piston and modifying the position of the valve member, thereby changing the value of the pressure transmitted to the associated compartment.

Abstract: This disclosure relates to an improved electro-hydraulic pulse motor wherein safety valves are arranged in hydraulic circuits provided for the hydraulic motor part of an electro-hydraulic pulse motor so as to release abnormal high pressure produced in the circuits due to sudden interruption of the operation of an electric pulse motor part of the electro-hydraulic pulse motor. As a result, breakage of the circuits or four way pilot valve part of the electro-hydraulic pulse motor can be avoided.

Abstract: A fluid-pressure operated actuator arrangement has a double-acting actuator device and a control valve. A three-element differential mechanism has two of its elements respectively drivingly connected to the control valve and the actuator device, and a third element resiliently coupled to an input lever. The input lever is frictionally restrained against movement. Relative movement between the lever and the third element, induced as a result of jamming the control valve, brakes the third element, increasing a torque which can be applied by the actuator device to the valve.

Abstract: A steering worm shaft in operational connection with a steering wheel and communicating with an axially slidably arranged steering gear nut, which gear nut affects an additional gear member, for example, by means of a toothing, and simultaneously functions as a servo-piston or is at least fixedly connected to a servo-piston within a housing, which contains a cylinder space; the servo piston dividing a cylinder space into two operational spaces, which are separated from each other, and the steering gear nut at its outer cover is provided with an outwardly extending, axially directed lever in an area remote from the sealing area of the servo-piston; the axial width of the lever corresponding at least with the lift of the servo-piston and engaging an axial-parallel groove in the housing to allow the lever to perform a minute tilting movement relative to the housing when the steering gear nut, due to friction and rise of the worm gear nut during a rotation of the steering worm shaft, is also set into rotation, wh

Abstract: A power assisted steering system for a vehicle including a steering wheel operatively connected to steered wheels comprising a housing, a nut-and-screw mechanism comprising a nut member and a screw member, an input shaft mounted in said housing, at least one flexible shaft connected at one end to the steering wheel and at its opposite end to said input shaft, intermeshing gear means carried by said input shaft and one of said members of said nut-and-screw mechanism, means operatively connecting the other member of said nut-and-screw mechanism to the steerable wheels, the members of said nut-and-screw mechanism being of a configuration to preclude rotation relative to one another whereby upon rotation of one of said members, the other member is actuated in a rectilinear direction to thereby effect movement of the steered wheels, hydraulic circuit means including a double-acting servo-cylinder and a control valve including a slide member for controlling flow of hydraulic medium to and from said servo-cylinder,

Abstract: A servo steering system for motor vehicles has a stepped servo piston arranged in a cylinder-forming space of a housing for dividing the cylinder space into a pair of separated working spaces of different volumes. The servo piston is engaged by a worm shaft connected to a steering wheel of the vehicle and arranged extending into the housing. The working space having the larger volume is connected to a pressure source by a valve member operatively connected with a lever associated with the servo piston for controlling fluid flow through the working space and magnifying movement of the worm shaft, with the smaller volume working space of the servo piston being connected directly to the pressure source. Reaction spaces of a stepped control piston of the valve member are substantially in the same ratio as the working spaces of the servo piston.

Abstract: Herein disclosed is an automotive power-assisted steering system which comprises a hydromechanical leverage unit drivingly connected to a steering linkage, a rotary piston-valve hydraulically connected to the leverage unit, a motor to move the piston-valve for actuating the leverage unit to a right-turn or left-turn position, and a valve re-set mechanism connected between the leverage unit and the piston-valve for moving the valve into an equilibrium position from a condition bringing the leverage unit into the right-turn or left-turn position, wherein the motor is energized by a pulsating current which is controlled in accordance with a signal representative of the angle and direction of turning of a steering wheel and, where desired, signals representative of a vehicle velocity and an external force which may be sideways imparted to the vehicle by a side wind blowing onto the vehicle.