Abstract: A control valve controls hydraulic pressure of oil supplied to a hydraulic actuator for generating steering assist power, based on elastic relative rotation between input and output shafts. A restricting device restricts relative rotation between input and output shafts based on a driving condition of the vehicle, and adjusts the hydraulic pressure for pressing the input shaft via a plunger inserted into a guide bore formed in the output shaft, based on the driving condition of the vehicle by the hydraulic pressure adjustment mechanism. The plunger is guided by the inner circumference of the guide bore along the direction that the plunger approaches to and goes away from the output shaft when the input and output shafts relatively rotate. A friction reducing element is interposed between the inner circumference of the guide bore and the outer circumference of the plunger.

Abstract: A feedback control system (i.e., a positioner) for precise positioning of a pneumatic actuator by adjusting the flow of air to the pneumatic actuator comprises an adjustable gain mechanism for adjusting the sensitivity of the positioner. The adjustable gain mechanism is coupled between a feedback input device of the positioner and a valve control device and is employed to adjust the amount of air supplied to the pneumatic actuator for a given displacement of the feedback input device. Preferably the adjustable gain mechanism is adjustable through a range of settings between a high gain setting and a low gain setting, the high gain setting allowing a greater range of motion of the valve control device than the low gain setting for a given displacement of the feedback input device.

Abstract: A power steering control valve including relatively rotatable inner and outer valve members. A power steering resistance control system resists relative rotation between the inner and outer valve members with a force which varies as a function of variations in vehicle speed and steering demand. The power steering resistance control system includes a force transmitting member which is disposed adjacent to one end of the outer valve member. A spring force is applied against the force transmitting member urging it in a first direction along the axis of rotation of the valve members. Fluid pressure is applied against the force transmitting member to urge it in the first direction. A valve is operable to vary the fluid pressure applied against the force transmitting member. A solenoid valve controls the position of the valve as a function of vehicle speed and steering demand.

Abstract: A valve positioner has a pneumatic transducer responsive to a signal pressure for displacing a spool valve away from a neutral position to effect actuation of an actuator output shaft and further includes a gain adjustment apparatus. The pneumatic transducer includes a balance beam being operably connected at one end to the spool valve and at the other end to a hinge spring. A clamp mechanism is attached to the hinge spring and is slidably adjustable along the length of the hinge spring to vary the spring characteristics. The hinge spring tapers in thickness such that the spring increases in thickness in a direction from a first end of the spring towards the balance beam. A window or cut-out is also provided in the hinge spring to further assist in varying the spring characteristics as the clamp mechanism is moved along the hinge spring, and provide a wide range of gain adjustment over the single spring.

Abstract: A hydraulic sensor and pressure transducing apparatus is disclosed which is characterized by the use of a biased piston and valve element arrangement to translate the displacement of an actuator to provide a pressure signal proportional to the displacement being sensed. The piston is mounted in a bore provided with inlet and outlet ports. A valve element is positioned in the bore in an opposing resiliently biased relationship to the piston in communication between the inlet and outlet ports. A constant selected hydraulic flow is fed into the bore inlet through the valve element and out of the bore outlet port to develop a pressure on the inlet port side which is proportionally to the displacement of the piston as reflected by the biased force exerted against the valve element. An actuator is linked to the piston by a cam surface in a manner that permits the angular position of the cam operating on the piston to be reflected as a proportional pressure on the inlet side of the valve element.

Abstract: A vacuum brake booster (12) having an input force applied to a brake pedal (20) for moving a plunger (28) to operate a control valve (24). A sleeve (98) concentric to the push rod (22) is located between the brake pedal (20) and plunger (28). A spring (94) acts on the sleeve (98) to move the plunger (28) against a stop (76) in the absence of an input force. A ramp (104) on sleeve (98) cooperates with projection (102) on said push rod (22) to define a linear dimension for the spring (94). Rotation of the sleeve (98) changes the load of the spring (94) and correspondingly the force required to initiate the operation of the control valve (24) through movement of the plunger (28).

Abstract: An electrohydraulic control system for a hydraulic working cylinder, for example of a press, the piston of which has a main working surface and a smaller working surface on the rod side. A low-pressure circuit is provided for the feed or retraction movement of the piston, and a high-pressure circuit is provided for the loading movement at increased feed force and reduced speed. The connection or disconnection of these two circuits, when required, is produced with two 3/2 way valves that are coupled together. To control these control valves, there is provided an electrical reference motor that drives a cam disk which brings about the deflection of the coupled control slide valves of the control valves against a spring. A mechanical feedback is provided via the power piston, so that altogether a closed hydromechanical position control circuit is formed.

Abstract: A pneumatic booster including a housing, a power piston partitioning the interior of the housing into a front chamber and a rear chamber, with the front chamber being connected permanently to a source of a first reference pressure, the rear chamber being selectively communicated with the front chamber and a source of second reference pressure which is higher than the first reference pressure through a valve mechanism, an output shaft receiving the output force from the power piston, and an input shaft receiving an input force for actuating said valve mechanism and receiving a reaction force of the output force. There are provided a device between the output shaft and the power piston for changing the reaction force with respect to the output force on the output shaft, a mechanism for rotating the output shaft around the axis thereof, and a device for preventing the rotation of the power piston relative to the housing at least at the non-actuated condition of the pneumatic booster.

Abstract: In the case of a pressure-worked automatic control system with a closed loop, and, more specially, a position automatic control system, the position of a servo-element is dependent on a spring placed between the servo-element or servo-motor and the sensing unit of the position automatic control system. The spring, placed between the servo-element or servo-motor and the sensing unit of the position automatic control system, is made up of at least one spiral spring, whose one end is able to be turned by a moving servo-part of the servo-element or servo-motor, while its other end is designed for acting on the sensing unit of the position automatic control system.

Abstract: A pneumatic valve actuator having a rotatable output shaft is provided with a valve positioner comprising an axially displaceable spool valve and a pneumatic transducer responsive to applied signal air pressure for displacing the spool valve away from a neutral position to effect rotation of the actuator output shaft. The actuator output shaft is gear-connected to an element which rotates with the output shaft, and an elongated cantilever beam spring attached at one end to the rotatable element extends in a direction transverse to the axis of rotation of said element to the transducer for providing a feedback force which balances the control signal responsive transducer force when the actuator output shaft has rotated to a desired position.

Abstract: An electrohydraulic servovalve including a second stage piston slidably mounted within a housing and movable responsive to application of pressure signals thereacross to control the flow of fluid under pressure from a source to a load in response to electrical input signals applied to the servovalve. The electrical signals are applied to a torque motor which has a driven member affixed thereto which generates the pressure signals applied to the spool. A mechanical feedback member is connected between the driven member and the spool. The mechanical feedback member is part of an assembly which is removably attached to the driven member. The removable attachment includes a tang extending radially from the driven member which receives a holder to which the feedback member is permanently affixed. The holder includes opposed flanges one of which receives the tang through an indexing opening provided therein.

Abstract: Device for moving and positioning an element of a machine comprising a hydraulically controlled valve shaft sliding in a sleeve and two output ducts in which the oil pressure depends on the position of the valve shaft. The oil pressure in the two output ducts is supplied respectively to two compartments of a hydraulic jack which positions and moves the carriage or slide of a machine tool. Two control chambers in between the valve shaft and sleeve jack include a constant volume part formed between shoulders on the valve shaft and a variable volume part formed by a slidable piston inside of a longitudinally extending cylindrical cavity inside the valve shaft. The cylindrical cavities extend to respective outer ends of said valve piston with fixed stops attached to the sleeve ends. The valve shaft is mechanically coupled to the mobile unit with the jack by a spring biased lost-motion pivot lever connection.

Abstract: A positioner for a fluid-operated actuator has a fluid control valve displaced by a controlling force applied to a force-balance lever engaging one end of a biasing spring, the other end of which engages feedback means including an element displaceable by actuator movement. The valve lies between the biasing means and said feedback means element. Adjustment means are provided for the spring and for the feedback means to set the actuator zero position and movement range. Fluid conduits from the valve comprise open channels in a unitary member containing the valve and with a wall of a housing form closed section passages to porting in said wall opening directly into the actuator porting.