Abstract: A reaction rod retainer for vacuum booster and a method for retaining a reaction rod, the reaction rod retainer for vacuum booster comprising a hollow annular body, wherein a plurality of outer ribs extend radially outwardly from an outer edge of the body, and wherein a plurality of inner ribs extend radially inwardly from an inner edge of said body. The reaction rod retainer guarantees tightness and firmness of combination of the reaction rod and feedback plate, in addition, it has an advantage of simple structure and meanwhile reduces the cost. The method for retaining reaction rod provided also has advantages of simple assembly and being easy to assemble.

Abstract: Provided is a negative pressure type booster device, in which a diaphragm of a movable partition wall has, in a penetration portion through which a tie rod bolt hermetically penetrates, a tubular guide portion that abuts against an annular flange portion provided on the tie rod bolt during forward movement of a power piston, and an annular sealing portion that is provided in the rear of the guide portion to block communication between a negative pressure chamber and a variable pressure chamber. The guide portion is provided with a communication portion through which a negative pressure chamber side space exposed by the front surface of the sealing portion communicates with the negative pressure chamber, even in a state in which the guide portion abuts against the annular flange portion.

Abstract: A pneumatic actuator has a first service chamber assembly featuring a first housing defining a first chamber and a second service chamber assembly featuring a second housing defining a second chamber. A first diaphragm divides the first chamber into a first pressurized air side and a first spring side while a second diaphragm divides the second chamber into a second pressurized air side and a second spring side. An actuator rod extends out of the second housing. A connecting actuator rod is connected to the actuator rod and the first diaphragm. Pressurized air inlet ports are in communication with the first and second pressurized air sides of the first and second chambers respectively. The first and second diaphragms cooperating to further extend the distal end of the actuator rod away from the second housing into an extended position when pressurized air is introduced into the first and second pressurized air sides of the first and second chambers.

Abstract: A method for securing the assistance torque (15) supplied by an electric assistance motor (8) in a motor vehicle power steering system includes the steps of: estimating the force on the steering system rack from the torque exerted by the driver on the steering wheel (2), from the assistance torque (15), and optionally from other parameters such as the speed of the electric assistance motor; comparing a target assistance torque with an authorized assistance range, defined with respect to the estimated rack force (17) at any moment, and in the event the target assistance torque is maintained above predefined limits for a predefined duration, correcting and optionally interrupting the power steering.

Abstract: The invention relates to a vacuum brake booster having a chamber arrangement for producing a servo force that supports a brake actuating force, wherein the chamber arrangement comprises a housing, in which a working chamber is separated from a vacuum chamber by a movable wall, wherein the housing has a first housing shell and a second housing shell, which are or can be connected to each other in a sealing manner in a connection area, wherein a flexible section of the movable wall is arranged in a sealing manner in the connection area, and wherein the housing shells of the housing are penetrated by at least two fastening bolts in order to fasten the vacuum brake booster to a vehicle chassis. For easier assembly, at least one of the fastening bolts is provided with an engagement formation, with which one of the housing shells can be brought into engagement during the assembly, and thus said housing shell can be permanently locked in a predetermined position relative to the other housing shell.

Abstract: A hydraulic power steering system for a ground vehicle includes a closed-center control valve, a fluid supply line and an exhaust line extending into the control valve and first and second motor lines extending out of the control valve to a fluid motor. An additional flow line extends from each motor line to the exhaust line and contains a check valve that allows flow in the flow line only towards the motor line. The additional flow lines enable manual steering in the event fluid supply is lost without leakage loss during normal on center operation.

Abstract: A method is disclosed for detecting the drive type of an actuator, e.g., a pneumatic actuator, having a positioner for operating a final control element in a process engineering plant. The actuator is connected to the positioner by a mounting set, the positioner comprising an electronic control unit, which uses a microcontroller to receive one or more input signals, and to output actuating signals to control the flow of gas to or from the chambers of a single-acting or double-acting pneumatic drive. The position feedback sensors are equipped with a rotational measuring system. During commissioning of the actuator, the relationship between the drive volumes and the position signal is found and compared with transfer characteristics of known drive types. Where there is a match between the transfer characteristic defined by the value pairs of the given actuator and one of the transfer characteristics of the known drive types, the identified drive type is assigned to the given actuator.

Abstract: A control device for the position control of a hydraulic cylinder unit has a controller which receives a set and an actual piston position and determines a preliminary manipulated variable based on the difference of the set and actual positions. A linearization unit multiplies the variable with a linearization factor and outputs it to the valve control unit so that the piston is adjusted at an adjustment speed. The linearization unit determines the factor dynamically as a function of the actual piston position and of working pressures that prevail at both piston sides. The linearization factor is determined such that a ratio of the adjustment speed to the difference of the set and actual positions is independent of the actual position and the working pressures. In the specific case where the controller is configured as a P controller, the order of the controller and the linearization unit can be reversed.

Abstract: An axial piston device for use with a hydraulic system is disclosed. The axial piston device may have a body defining at least one bore and having a central axis, a pump piston disposed within the at least one bore to at least partially define a pumping chamber, and a tiltable plate biased into engagement with the pump piston. The axial piston device may also have an actuator configured to selective tilt the plate relative to the central axis of the body to thereby vary a displacement of the pump piston within the at least one bore. The actuator may have a control piston operatively connected to move the tiltable plate, a rotary motor, and a valve driven by the rotary motor to control fluid communication between the control piston and a source of pressurized fluid to move the control piston.

Abstract: A pneumatic actuator, connected to a pressure fluid circuit (6) that has a high pressure side and a low pressure side, an actuator cylinder (8, 9), an actuator piston (10, 11) provided in said actuator cylinder (8, 9) and displaceable between a first position and a second position, an actuator chamber (12, 13), delimited by said actuator cylinder (8, 9) and the actuator piston (10, 11), wherein the volume of said actuator chamber decreases upon a displacement of the actuator piston (10, 11) from the second to the first position to the first position, a spring means provided to drive the actuator piston (10, 11) from the second position to the first position, and means (25) provided to maintain or establish a communication between the low pressure side and the actuator chamber (12, 13), during a displacement of the actuator piston (10, 11) from the second position towards the first position, and at the same time to keep the communication between the high pressure side and the actuator chamber (12, 13) interrup

Abstract: The disclosure relates to a method for identification of the drive type of an actuating drive, e.g., a pneumatic actuating drive, having a position regulator in order to control an actuating member in a process installation. The actuating drive is connected by means of an attachment to the position regulator, with the position regulator having control electronics which receive one or more input signals with the aid of a microcontroller and emit actuating signals in order to ventilate or vent the chambers of a single-acting or double-acting pneumatic drive. The position feedback sensor system is equipped with a rotational measurement system. The actuating range of the actuating drive is passed through completely while setting it up. The angle positions signaled back are recorded. The drive type is determined from the range between the limit angle positions at the actuating range limits of the actuating drive.

Abstract: This invention relates to a brake booster (201) having an axis (X), comprising an enclosure divided into a front chamber (210) and a rear chamber (208) by a skirt (209) fastened to a piston (205) mounted so that it can slide in the axial direction (X), the booster comprising a nonreturn valve (225) to evacuate air from the front chamber when the pressure prevailing exceeds a certain reference value. According to this invention, this booster is characterized in that this nonreturn valve (225) is internal to the booster (201).

Abstract: For a hydraulic servo-assisted steering system for motor vehicles, classifying storage of the respectively measured, actual valve characteristic curves is provided and, corresponding to this, energization characteristic curves for the magnetic actuator of the converter are provided, which may be paired in a classified manner in order to compensate for deviations from a predefined set valve characteristic curve, and a testing method for such a hydraulic servo-assisted steering system is provided, in which the loading pressure of the servo actuator is influenced as a function of an input steering torque and in a speed-dependent manner, the speed-dependent influence being effected via the electro-hydraulic converter, whose energization may be set in a manner superimposed on the speed-dependent definition with regard to the correction of tolerances.

Abstract: An electrohydraulic valve actuator assembly for an engine includes a movable engine valve, a movable spool valve, and a driving channel interconnecting the spool valve and the engine valve. The electrohydraulic valve actuator assembly includes an actuator operatively cooperating with the spool valve to position the spool valve to prevent and allow fluid flow in and out of the driving channel to position the engine valve. The electrohydraulic valve actuator assembly further includes a mechanical feedback interconnecting the engine valve and the spool valve to control the position of the spool valve.

Abstract: A hydraulic drive (1) has a position selection device (2) in communication with a control valve (3) which, as a function of the actuation of the position selection device (2), controls the connection of an actuating cylinder (8) with a hydraulic fluid source (5) and a reservoir (6). A correction device provides a synchronization between the position of the position selection device (2) and the position of the actuating cylinder (8). The correction device has a sliding valve means (15) which detects a reference range of the actuating cylinder (8) and an on-off valve means (16) effectively connected mechanically with the position selection device (2). The on-off valve means (16) is open when the position selection device (2) is in the reference range and is closed when the position selection device (2) is not in the reference range.

Abstract: A depth control system particularly useful for single point depth control on an agricultural implement includes a valve and actuator mounted directly to the pivotal connection areas of a hydraulic cylinder that controls height. Cylinder motion directly controls valve actuation independently of complicated linkages to reduce the size and cost of the system and substantially overcome hysteresis problems.

Abstract: There is provided a pneumatic booster having an ejector, which achieves space-saving and enables easy piping.

Abstract: In this invention, an idea is adopted in which the pressure at a forward portion and a backward portion of valve device is steppingly dropped twice. The valve device of the present invention includes, on the axis of a spool 600, a first valve 710 located nearer an inlet port and a second valve 720 located nearer an outlet port. A throttling area made by the second valve 720 is larger than a throttling area made by the first valve 710. For example, of all the pressure difference equal to 120 kg/cm2 or more reauired at the forward and backward portions of the valve device, a portion in the range where the problem of an occurrence of a foreign noise is not encountered (for example, a portion ranging from 100 to 120 kg/cm2) is undertaken by the first valve 710, and the remaining portion ranging from 20 to 30 kg/cm2 is undertaken by the second valve 720.

Abstract: A valve actuation system with cooperating pneumatic and hydraulic control features. Compressed pneumatic fluid is generated in a pneumatic fluid supply, and flows in response to requirements between a predetermined command signal and an existing position of a working fluid valve. Hydraulic fluid is pressurized by a pump, and stored within the system by an accumulator. A servo valve comprising a pneumatic fluid flow path and a hydraulic fluid flow path is included to facilitate the flow of hydraulic fluid through the servo valve hydraulic fluid path and a downstream actuator for the working fluid valve in proportion to changes in pneumatic fluid flow through the servo valve pneumatic fluid flow path. A saturated fluid feedback circuit is included to shut off the flow of pneumatic and hydraulic fluid during select periods, such periods typically coincident with static conditions within the actuator of the working fluid valve, thereby reducing pump duty cycle.

Abstract: A booster 3 has a structure that a return valve 14 is formed into a two-step throttle incorporating a first throttle valve 36 and a second throttle valve 37 formed continuously from the first throttle valve 36. When a valve spool 28 has been moved forwards when the operation is performed, a gap of the first throttle valve 36 is reduced. Also a gap of the second throttle valve 37 is reduced. Therefore, hydraulic fluid discharged from a pump is passed through an inlet passage 12, and then introduced into the second annular groove 13. Then, the hydraulic fluid is throttled by the first throttle valve 36, and then throttled by the second throttle valve 37. That is, the hydraulic fluid is throttled in the two-step throttling manner. As a result of the two-step throttling structure, the overall velocity of the flow of the hydraulic fluid can smoothly be changed without rapid change. Therefore, fluid flow noise caused from the change in the velocity of the flow can be prevented.

Abstract: The invention relates to a device for modulation of servo pressure in a steering gear (1) comprising an input shaft (2) which is attached to a rack (4; 4'), a servo mechanism (9-17) for supply of power to the rack (4; 4') and comprising a box (8; 8) with a first channel (18, 20, 21) and a second channel (19) for the supply and return, respectively, of servo medium, and a connection channel (22; 29, 30) between the first and the second channel (18, 20, 21, 19). The invention further comprises means (28; 36) for detecting whether the rack (4; 4') is in a predetermined position, and a valve member (23; 31) for opening the connection channel (22; 29, 30) when said position is detected.

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: A fluid power apparatus is connected to a pressurized fluid supply and a conventional helm pump controlled by the helm of a vessel to shift the rudder. The apparatus comprises an actuator cylinder connectable to the rudder, and a servo cylinder and a main valve connected to the helm pump to pass fluid therebetween and between the actuator cylinder. The actuator cylinder and servo cylinder have respective bodies and piston rods, and portions of the servo cylinder and actuator cylinder are connected together for concurrent simultaneous movement along respective longitudinal axes. Valve shifting structure is responsive to a change in fluid signal from the helm pump applied to the servo apparatus. Fluid diverting structure is responsive to a threshold supply pressure so as to actuate the valve to stop flow of supply fluid when supply pressure drops below the threshold pressure.

Abstract: A load balancing arm is shown and described as having improved control including a programmable control element and electronic air regulation to provide precise and controllable lifting force on a load. The disclosed load balancing arm responds to slight operator applied force to aid in movement of the load in overcoming system hysteresis, friction and load inertia without requiring the operator to apply a sufficiently large magnitude force to overcome such counteracting forces in the system. The disclosed load balancing arm further includes automatic load weight detection sensors for accommodating variation in load weights while applying a lifting force to the load which substantially equals the weight of the load. This allows the operator to move the load freely throughout a work space.

Abstract: A fluid power apparatus is connected to a pressurized fluid supply and a conventional helm pump controlled by the helm of a vessel to shift the rudder. The apparatus comprises an actuator cylinder connectable to the rudder, and a servo cylinder and a main valve connected to the helm pump to pass fluid therebetween and between the actuator cylinder. The actuator cylinder and servo cylinder have respective bodies and piston rods, and portions of the servo cylinder and actuator cylinder are connected together for concurrent simultaneous movement along respective longitudinal axes. Valve shifting structure is responsive to a change in fluid signal from the helm pump applied to the servo apparatus. Fluid diverting structure is responsive to a threshold supply pressure so as to actuate the valve to stop flow of supply fluid when supply pressure drops below the threshold pressure.

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

Abstract: The device comprises a lever movable by the operator between at least two working positions and a neutral position to achieve, by means of an hydraulic actuator of double acting follower type, of the gear ratios in one stage of the gear box. The actuator comprises a piston slidable between two working positions and one neutral position to actuate engagement means and defining two chambers; and a shaft connected to the lever by means of a motion transfer unit and shaped as an hydraulic distributor in such a way that in the neutral position of the lever the chambers are connected to a discharge opening so as to determine the neutral position of the piston, and in a manner and in an operative position the stroke of the shaft causes communication of one chamber with the opening and of the other with an inlet opening for a fluid under pressure such that the pressure will translate the piston in the same direction and with the same stroke as the shaft. (FIG. 4).

Abstract: A pump/motor control mechanism comprising a first actuator for actuating forward a forward/backward member when a fluid pressure is introduced into a first cylinder chamber located in the forward/backward member, a second actuator for actuating backward the forward/backward member when a fluid pressure is introduced into a second cylinder chamber located in the forward/backward member at a position oppositely facing the first actuator, a spool holding hole which is provided in the forward/backward member and has an axis center parallel to the forward/backward direction, a spool which is slidable fitted in the spool holding hole and has on its outer periphery a high-pressure groove connected to a high-pressure fluid source and a low-pressure groove opened to a low-pressure zone, input means for driving forward or backward the spool, a first pressure introducing path whose one end is connected to the first cylinder chamber and whose other end is opened to an area which is on the inner periphery of the spool hol

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

Abstract: The invention relates to a brake servomotor assembly (1) consisting of a front half-shell (6) and a rear half-shell (8) and mounted on a stationary part (4, 40) of a vehicle by means of lugs (54, 56, 154) arranged in a plane perpendicular to the axis of the servomotor and around this axis, extending radially outwards and cooperating with bearing surfaces (34, 36, 134) with corresponding shapes and dimensions for mounting by mechanism of axial engagement followed by rotation, an elastic means (25, 125) being arranged between the servomotor (1) and the stationary part (4,40), the servomotor (1) having a central hub (24) on the rear half-shell (8) comprising a control valve mechanism (26) of the servomotor (1). The lugs (154) or the bearing surfaces (34, 36) are formed as a single piece with the central hub (24) and cooperate respectively with the bearing surfaces (134) or the lugs (54, 56) formed on the stationary part (4, 40) of the vehicle.

Abstract: A hydraulic pressure booster which may be used in a brake system of a vehicle is constructed to allow a brake output to be increased upon ceasing the depression of a brake pedal, thus imparting a brake feeling which is favorable to a driver. Hydraulic pressure from a first power chamber flows into a second power chamber through a passage provided with an orifice in shunt with a check valve, such that flow from the first power chamber to the second power chamber is retarded while flow from the second power chamber to the first power chamber is unrestricted.

Abstract: An optical actuator position demand signal through optic fiber 14 is focused on one side 32 of optical fluidic interface 16. A second optical signal through optic fiber 56 is attentuated 50 in proportion to actuator 38 position and focused on a second side 34 of the interface 16. Amplified fluidic signals 68, 70 drive the actuator until the demand signal 14 and actual signal 58 are in balance.

Abstract: An elevating apparatus for a working vehicle includes separate front lifting and rear lifting mechanisms that can be elevated by hydraulic cylinders, a feedback rod arranged between a link arm of one of the lifting mechanisms and a hydraulic pressure control apparatus for controlling the hydraulic cylinders. A change-over lever selects the front lifting mechanism or the rear lifting mechanism, and an elevating lever controls elevation of the lifting mechanisms. When one of the lifting mechanisms is selected and elevated by operation of the change-over lever, the elevating lever is operated normally without causing abutment between an adjuster member attached to the feedback rod that is interactive with the elevating lever, and an interactive member of the elevating lever. A return mechanism between the change-over lever and the elevating lever enables the elevating lever to be returned to the neutral position when selecting one of the front and rear lifting mechanisms.

Abstract: A servoactuator unit to operate flight-control mechanisms, in particular for control of the position of the oscillating plate which adjusts the cyclic pitch and collective pitch of helicopter rotors, in which two pairs of hydraulic actuators are used, connected together in parallel, arranged with their axes parallel and close together like the diagonals of a quadrilateral, their rods connected together at their end and acting on the said oscillating plate and the cylinders also being connected together at the back. Each pair of actuators is powered, through a servovalve, by an independent hydraulic circuit so as to enable operation even in the event of one of the pairs breaking down, with symmetrical stress being placed on the pair of actuators during operation.

Abstract: Apparatus is for controlling load on an engine, particularly a marine engine powering a controllable pitch propeller which serves as an engine loading device. Apparatus cooperates with a circuit having a supply fluid at a constant supply pressure, and a control fluid at a variable control pressure reflecting engine load. The apparatus has a signal receiver to receive a load demand signal from an operator, and a positioner apparatus with a positioner output which cooperates with the loading device of the engine. The positioner apparatus receives the supply and control fluids and has a partition separating the fluids to permit interaction therebetween to control the positioner output. The apparatus has a hydraulic fluid valve to control flow of hydraulic fluid relative to the positioner apparatus, the fluid valve being connected to the positioner output and an output of the signal receiver so as to be responsive to relative positions of both outputs.

Abstract: A wheeled vehicle is equipped with a feedforward steering control system which steers the vehicle through front or rear road wheels in accordance with a driver's steering input such as an angular displacement of a steering wheel, and a negative feedback system which senses a turning behavior of the vehicle such as a yaw rate or a lateral acceleration, and steers the vehicle through the front or rear wheels in such a negative direction as to reduce the turning behavior. The feedforward system may control the angular direction of the front or rear wheels in accordance with a linear combination of the steering input and the time derivative of the steering input, or may control the angular directions of both of the front and rear wheels in accordance with different transfer functions between the steering input and the front and rear wheel angles. The negative feedback system is combined with the feedforward system in various ways to provide desired characteristics of the turning behavior.

Abstract: The invention relates to a direct acting pneumatic control system for controlling a dual diaphragm, or double acting cylinder type automatic guiding system. The control device and system is used to selectively adjust the position of one end of a roll relative to the opposite end, in order to adjust the position of an endless web traveling over a series of rolls.In order to adjust and control the guide roll position, it is necessary to alternately exhaust one diaphragm, and or cylinder end, while maintaining the flow of air to the opposite diaphragm or cylinder end. This in effect shifts the roll in a lateral position, effectively steering the web in the proper direction to effect the necessary web correction.

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 brake booster includes a valve assembly to control communication of fluid pressure to a pressure chamber for the purpose of providing a power assist during braking. The valve assembly comprises a plate-like member cooperating with a pair of cylinders to selectively charge and vent fluid pressure through passages defined by the cylinders.

Abstract: A steering apparatus, which includes a device for fluid power-assist of manual steering forces transmitted to a steering gear, a control valve controlling operation of the fluid power-assist device, a valve body of the valve being actuated in accordance with a signal indicative of steering conditions and a steering reactive-force transmitting member directly transmitting steering reactive forces to the valve body so as to displacing same in response to an abnormal steering reactive force. The steering reactive-force transmitting member corrects an abnormal position of the valve body by engaging and moving the valve body when the reactive force exceeds a predetermined magnitude.

Abstract: A fluid flow selector valve for controlling step-by-step displacement of an on/off actuator (12), e.g. for controlling a flap in an installation for heating or for air conditioning the cabin of a motor vehicle. The valve comprises two mutually movable elements (80, 84) defining at least two chambers (90, 92) therebetween suitable for connecting the actuator feed inlet (30) to a source of fluid pressure (72) or to an exhaust. The valve further comprising an intermediate chamber (94) suitable for connecting the feed inlet to the source of fluid pressure (72), to the exhaust, or to an air tight seal.

Abstract: A steering compensator for providing resistance to movement of a steering system away from a preselected center position until a steering force exceeds a preselected value which may be varied remotely while the vehicle is in operation. The preselected center position may also be varied remotely while the vehicle is in operation by a trim mechanism. The compensator may be rotary or linear and the resistance force may be provided by a variable spring force and/or a variable magnetic force. Optional features include a liquid system for viscous dampening and an undercut seat and cam arrangement for centering without significant slack or overshoot.

Abstract: Valve for controlling a power-assisted rack-and-pinion steering mechanism, of the slide-valve kind, whose slide member 11 moves along an axis different from that of the pinion 1 as a result of the axial movement of the pinion produced by the thrust exerted on it by the rack because of the inclination of its teeth, said slide member being connected to the pinion through a kinematic mechanism with a high transmission ratio consisting of a rubber ring, all outer surfaces of which are enclosed by rigid walls, a push-rod 10, and resilient means pressing one against the other said rubber ring, push-rod and slide member in such a way that the displacements of the slide member is given by the displacement of the pinion multiplied by the ratio between the area of the rubber exposed to the axial thrust acting on the pinion and the area of the cross-section of push-rod 10.

Abstract: Step control apparatus for a fluid motor includes a plurality of devices each responsive to an external signal for initiating movement of the fluid motor. Also included is a mechanism for stopping movement of the fluid motor upon movement thereof a discrete step. Thus, a sequence of external signals applied to the devices effects movement of the fluid motor in a stepping mode. Optionally, an assembly may be provided for effecting movement of the fluid motor in a free-running mode.

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: A changeover valve unit for a power-assisted steering system includes input and output shafts arranged within a valve housing for relative rotation on aligned axes, a spool valve element concentrically assembled with the input shaft to be axially moved in response to relative rotation of the shafts for controlling the supply of fluid under pressure to a hydraulic cylinder associated with the steering system. An annular seal member of elastic material is secured at its inner periphery to the input shaft and is integrally formed with an annular lip facing the inner periphery of the spool valve element with a predetermined annular clearance. The annular lip is expanded outwardly by back pressure acting on the spool valve element at a higher level than a predetermined value and is brought into engagement with the inner periphery of the spool valve element.

Abstract: A tilting table for machining works is of the worm and worm wheel type incorporating a hydraulic servomechanism. A displacement of a stylus operating lever effected by the drive worm shaft moves the servocontrol valve out of its neutral position, thereby causing a tilting motion of the table in a desired direction via a hydraulic power unit of the mechanism. Due to a linkage connection between the table and the lever, the movement of the table always follows the lever so as to compensate the initial displacement, resulting in light and accurate positioning of the inclined table.

Abstract: An electrohydraulic control system with mechanical position sensing feedb is presented. A movable flight control canard is rotatably operated for providing flight control of the missile. A hydraulically powered actuator is mounted to the airframe with the canard being secured to the actuator shaft for controlled rotation of the canard. Hydraulic fluid under pressure enters the actuator at its base controlled via a rotary valve. A stepper motor is mounted to the canard and is geared to drive the rotary valve as determined by digital control signals generated by the missile guidance computer. When the stepper motor receives a train of pulses, the stepper motor rotor rotatingly moves the rotary valve from the null or closed position to an open position admitting hydraulic fluid into the rotary actuator causing the canard to turn.

Abstract: A compensator is disclosed for centering a frame supported steerable member comprising part of the steering system for a vehicle. The compensator is connected between the frame and the steering system and comprises a cylinder containing a pair of pistons and an actuator for engaging the pistons in response to movement of the steerable member. A fluid system provides fluid resistance to off-center piston movement and fluid force for return piston movement and includes components for independently varying both the resistance and the return force. The compensator may include a trimming apparatus for remotely varying the center position of the steerable member and components for controlling the rate of both turning and return movements. Optional valves may provide for deactivating the compensator manually or in response to power steering system failure, overpressurization, or vehicle speed.

Abstract: Power steering with rotary drive shaft adapted to drive a pinion cooperating with a rack, comprising a distributor of pressurized fluid which comprises a slide valve coaxial with the pinion and a connecting rod passing axially through the pinion and connecting one end of the slide valve to a piece linked in rotation with said shaft, but free to slide with respect to this shaft, said piece being adapted to cooperate during its rotation with a bearing surface immovable in the direction of the axis of the pinion and sloping with respect to this axis, so that said piece, the rod and the slide valve move axially in response to a rotational movement of the shaft.