Abstract: Apparatus and method for hydraulic actuation via multiple synchronized hydraulic motors with air purging, synchronizing, and force limiting features.

Abstract: A hydraulic piloted pressure reducing and regulating valve which is fail safe for holding the valve at the last selected operating pressure in the event of the loss of control signals. A pressure regulating valve having a body and a control piston therein is provided with a pilot piston in the body which is adapted to be connected to a hydraulic pilot pressure. A spring is provided between the pilot piston and the control piston whereby the control piston can move in response to flow demands in the valve. A rod is connected to the pilot piston with a locking sleeve engaging the rod and releasably locking the rod and pilot piston against movement. A hydraulic pressure port is in communication with the space between the rod and the sleeve for releasing the rod upon application of pressure to the port. The port and the pilot piston are separately connected to a hydraulic fluid supply and a control system whereby upon failure the valve will maintain the last selected operating pressure.

Abstract: The invention relates to a hydrostatic steering device having a servomotor connectable to wheels to be steered. The travel limits of the servomotor are sensed with position sensors which function to operate a locking apparatus which mechanically prevents further turning of the steering wheel upon a travel limit being reached in either direction.

Abstract: A piston-cylinder assembly for displacing a load through a long stroke consists of a rod, a piston slidable on the rod and by fluid pressure the piston is clamped to the rod, and a cylinder in which the piston is contained. By clamping the piston to the rod and introducing fluid into the cylinder, relative movement is caused between the piston and cylinder and the rod. When one assembly is used, the movement is intermittent but, by mounting two pistons on the rod, each piston being in a separate cylinder, and by controlling the flow of fluid, the movement is continuous.

Abstract: A hydraulic cylinder having a locking device disposed in either, or both head ends which attach to the cylinder, has a piston reciprocally movable within a piston chamber formed in the cylinder. A stud member having a groove portion and a stud portion, secures to the piston for reciprocal movement therewith. The stud member axially moves within a stud bore formed in the head end such that, the stud bore acts as a variable volume stud chamber. A plunger member, disposed in the head end, is in fluid communication with the variable volume stud bore such that, movement of the stud member into the stud bore increases the fluid pressure, thus forcing the plunger out of contact with the stud portion of the stud member. When a predetermined pressure occurs, an outlet valve to the stud bore opens, reducing the fluid pressure and allowing the plunger to be urged into engagement with the groove portion of the stud member thus effecting a locked condition.

Abstract: The bogie of a railroad vehicle, in particular for city transportation, is provided with axles which can be oriented substantially along the radius of the curves of a railroad track. The primary suspension of the bogie comprises springs and guiding link-arms of variable length constituted by hydraulic jacks for modifying the angle of the axle with respect to the bogie frame according to the radius of the curve being negotiated.

Abstract: A hydraulic circuit for selectively extending and retracting a mobile telescoping boom assembly and for independently extending and retracting an articulated pipe service line mounted on the boom assembly. The circuit can be used with a hydraulic ram to extend and retract the boom assembly or a winch and cable arrangement can be used. A pair of winches are used to extend and retract the articulated service line.

Abstract: The invention is an integrated hydraulic control circuit for actuating the thrust reversers and variable exhaust nozzle on high preformance gas turbine engine powered aircraft. The hydraulic circuits for both systems are integrated into a single housing and are served by common elements. The circuit for the deployment and stowage of the thrust reverser buckets is hydraulically sequenced inhibiting the application of hydraulic power to the actuators prior to withdrawal of the locking pin. In a like manner, the thrust reversers must be fully retracted before the locking pin is deployed. The hydraulic circuit for the thrust reversers also includes a pressure compensating circuit which reduces the pressure applied to thrust reverser actuators with the thrust reversers in the stowed position.

Abstract: A system for pressurizing cavities arranged laterally of pivotal vanes of a variable primary nozzle system in a radial turbine. The cavities are supplied with fluid of increased or reduced pressure to resist the clamping forces of the mounting rings. The fluid may conveniently be influent pressure or nozzle discharge pressure as may be appropriate. Pressure to the cavities is controlled as responsive to the pressure in the actuator system for adjusting the nozzles.

Abstract: This invention relates to direct acting rotary actuator cylinders wherein the linear motion of the piston is directly converted to angular motion by a means completely enclosed within the cylinder, which means comprises a slidable partitioning body engaging the circular cylindrical cavity in the cylinder in an air-tight sliding relationship and a circular cylindrical rod coaxially and rotatably disposed in said circular cylindrical cavity having a mid-section with a noncircular cross section of a diametrical dimension greater than the diameter of said circular cylindrical rod.

Abstract: A double-acting hydraulic jack, comprising a hollow piston reciprocable in a surrounding cylinder, includes a tubular shaft extending axially inside and carrying a nut of the circulating-ball type which coacts with a screw coaxially disposed in that shaft. The screw is rigid with the piston whereby an axial displacement of the latter is translated into a rotation of the shaft; a toothed wheel on the shaft, engaged by a spring-loaded detent, acts as a one-way brake enabling such rotation only in one direction and blocking it in the opposite direction unless the detent is withdrawn by a hydraulic servomotor which is pressurized concurrently with the admission of fluid to the cylinder tending to displace the piston in the normally blocked direction.

Abstract: The control mechanism is for pneumatic apparatus of the kind comprising a piston-and-cylinder motor coupled between two relatively-movable parts (such as door-leaves) for driving them, when energized, to a predetermined relative position. A pilot valve is actuated when required to switch the apparatus to an emergency mode by isolating the motor from its power source and discharging it into an emergency reservoir having a volume large compared with the maximum volume of gas in the motor. While the pilot valve is actuated, the relatively-movable parts are urged towards their predetermined relative positions by a force small compared with the normal operating force. The pilot valve may be arranged to operate operation of an emergency release bolt, on obstruction detected by a detector valve (in which case a timing reservoir provides time delay before full power is restored), on power failure, or as required.

Abstract: A fluid actuator including a lock mechanism for locking the actuator against movement in one position and a fluid operated sequence-power valve which when actuated by fluid pressure releases the lock mechanism and then ports such fluid pressure directly to the actuator to cause movement thereof in the desired direction following release of the lock mechanism.

Abstract: This invention relates to a motor control unit and a feedback arrangement to minimize the effects of backlash in a rotary output system. The system includes a source of energy. The motor control has a directional control element moveable from a null position. The motor control unit is coupled to the source of energy and to a motor which in turn is coupled to the rotary output and to a second input of a differential harmonic drive that has first and second inputs and an output. The first input of the differential harmonic drive is coupled to a rotational command input unit and the differential harmonic drive output is drivingly coupled to the moveable direction control element. In response to a given rotational command input when the second input is in an initial static position, whereupon the motor is coupled to the source of energy through the motor control unit, the rotary output is driven a precise number of revolutions dependent upon the given rotational command input.

Abstract: A fluid operated pintle assembly for rotatively supporting a reel where clearance is provided between the walls of a pintle carrying piston and its cylinder and an annular diaphragm extends across the piston and cylinder in sealing engagement and extends down into the clearance.

Abstract: A fail-fixed electrohydraulic servosystem in which a variation from a predetermined range of electrical input to the servosystem results in the output of the system being fixed in position. Fixing-in-position is accomplished by either hydraulically or mechanically locking a linkage to the output arm of the servosystem. Provision is also made for controlled drift and manual adjustment of the output after it is fixed in position.

Abstract: Disclosed is a mechanical locking device for locking a rod in a conventional hydraulic actuator, such as a hydraulic cylinder or a rotary actuator. The device comprises a radially contractible locking ring having a cylindrical inner surface for gripping the rod when the locking ring is contracted and an outer surface which is axially inclined, means for positively securing the locking ring around the rod in a position axially fixed in at least one direction with respect to the actuator housing, a ring-contracting member around the locking ring and having an inner surface which is axially inclined at the same angle as the outer surface of the locking ring for engaging that surface, and means for applying an axial force to the ring-contracting member in the direction of the inner surface axial inclination to cause the ring-contracting member to slide axially on the locking ring thereby causing the locking ring to contract and grip the rod.

Abstract: A parking brake for use primarily on railway vehicles of the mass transit type in conjunction with the service brake apparatus but operable independently thereof. A parking brake hydraulic cylinder is mechanically connected to the brake shoe hanger of the brake unit. After the vehicle has been brought to a stop, a parking brake application may be made by supplying pressure, by a handpump, to the hydraulic cylinder which also includes a lock-nut actuable by the pressure, in excess of a certain pressure for locking the parking brake hydraulic cylinder in its applied position. A relief valve is provided for relieving the hydraulic cylinder of hydraulic pressure when the application is to be released.

Abstract: A hydraulic handbrake control system for vehicles has a hand operable reversible fluid pump and a shuttle valve operable to circulate fluid in one direction for applying vehicle handbrakes, and in another direction for releasing vehicle handbrakes by governing flow of fluid alternately in application and release directions over application and lock release passages connected to a plurality of hydraulic handbrake cylinders. An improved lock control mechanism is associated with each of the cylinders having a check valve permitting passage of fluid from the application passage to the associated brake cylinder, but preventing release of fluid when handbrakes are applied.

Abstract: A brake cylinder device including a brake piston operable by a spring force to an application position and to a release position in response to an opposing fluid pressure force, and a fluid pressure operable locking device operable responsively to release pressure for locking the piston in the release position and for delaying such locking of the piston in the release position during normal operations to prevent untimely locking-up of the piston.

Abstract: A digitally controllable pneumatic linear actuator in which a moving piston driven by compressed air is initially decelerated by the pressure of compressed air applied to the both sides thereof in the course of its advancing movement toward a predetermined stop position and is then braked by a mechanical brake, thereby obviating failure of precise positioning of the piston due to the compressibility of air. The piston displacement is digitally detected, and the result of detection is fed back to a digital controller.

Abstract: This device comprises two movable elements of rigid material tightly interconnected by means of a deformable membrane forming therewith a tight internal enclosure, means for varying abruptly the volume of said enclosure by successively moving the two elements away from each other, maintaining them in spaced relationship and allowing them to be urged toward each other by the effect of the external hydrostatic pressure, in which the means for moving the two elements away from each other includes two cylinders and at least one piston slidable in one of said cylinders, associated to one of said movable elements and also to a push-member slidable in one of the cylinders and bearing on the other movable element and means for feeding said cylinder with pressurized fluid so as to maintain the elements in spaced relationship or to release them.

Abstract: This disclosure relates to a system for protecting pneumatic cylinders and diaphragm valves against failure of both electrical and pneumatic supplies. In the event of a failure of the air supply, the loss of air pressure is detected and all drives are locked in position. The position pneumatic feedback signal from the pneumatic cylinder diaphragm valve is then connected directly to a pneumatic memory. Thus when the air supply recovers, the pneumatic memory will be equal to the instantaneous position of the pneumatic cylinder or diaphragm valve.In the event of an electrical failure, a solenoid valve interrupts the flow of the pneumatic signal from an electropneumatic transducer to the pneumatic memory, so that the air cylinder or valve is directly connected to the pneumatic memory. By selectively energizing a pair of solenoid valves connected to the memory, the operator using an emergency d.c.

Abstract: A valve group subassembly for use in a vehicle having hydraulically operable mechanisms. The subassembly includes the main valve and actuators, interconnecting duct structures, and a mounting bracket permitting the complete subassembly of the control elements. A pilot valve manifold is mounted to the bracket for hydraulic connection thereto of the pilot valves. The bracket may be resiliently mounted. The valves may be provided with removable valve stems, permitting the valve bodies to be maintained mounted to the bracket in servicing the individual valves. The subassembly is arranged to permit a bench testing thereof prior to the installation in the vehicle.

Abstract: A hydraulically or pneumatically controlled device for locking a piston in he bore of its cylinder at any point of its stroke, comprises, mounted on the piston, fluid-tight seals, a series of wedges, and annular jacks incorporated in the piston. The wedges are arranged to move in translation parallel to the axis of the cylinder under the effect of the annular jacks so as to absorb the increase in the radial plays between the piston and the bore of the cylinder on its pressurization. This peripheral extension which is produced between the bottom of the cylinder on its intake side and the fluid-tight end seal of the piston spaced furthest from it, is followed, after the release of the lateral walls of the cylinder, by a retraction of the lateral walls of the cylinder acting on the outer surface of the wedges. The latter exert a grip on the piston thus effecting positive locking by binding of the cylinder and of the piston.

Abstract: A hydraulic motor having a housing and a shaft journaled for rotation along the longitudinal axis of the housing. The shaft carries an eccentric on which is rotatably mounted a bearing block. The housing has a plurality of hydraulic cylinders grouped about the axis of the shaft in a common plane normal to the axis of rotation of the shaft with each cylinder having a hollow piston displaceable therein and biased in a direction toward the bearing block. The shaft and the eccentric have inlet and outlet passages communicating with the bearing block and adapted to communicate a source of hydraulic fluid pressure and an exhaust means respectively therewith. Means are provided on the eccentric for separating these passages from one another with the bearing block having a port communicating fluid from the aforementioned passages to the piston interior, whereby fluid pressure may be admitted to the cylinders in turn, one after another, during the operation of the motor to exert a direct thrust on the eccentric.

Abstract: The invention relates to a servo assembly having a stationary part including a housing, a movable member and a servo motor. Of primary interest is the stopping mechanism which includes a stop unit on the movable member and two pressure operated, vertically reciprocal stop members mounted in the housing. Two hydraulic circuits are provided with a first circuit for the two stop members and the second circuit for the servo motor. Throttle valving for the first circuit is provided between the two stop members and the housing. Prior to reaching a stopping position the stop unit on the movable member actuates a switch which relieves the pressure in the first circuit and causes one of the stop members to descend to an intermediate position where throttling occurs and the other stop member to descend to a final position where throttling may or may not occur. The throttling causes substantial braking of the movable member during a short distance of travel just prior to the stopping position being reached.

Abstract: A safety arrester for arresting a hydraulically operated lifting ram of a hydraulic elevator comprises an arrester body within which a plurality of brake shoes are located. The brake shoes are segments of a ring around a passage through the arrester body for receiving the ram, are spring biassed into frictional engagement with the ram, and are displaceable out of engagement with the ram by hydraulic actuator means.

Abstract: The motor grader drawbar assembly has a blade mounted on a circle gear and a drive unit operatively connected to the circle gear to selectively rotate it and the blade. A plurality of radially mounted pistons operate against an upright wall of the circle gear to provide a brake and/or locking mechanism. The pistons, and their accompanying cylinders, are mounted in members which also underlie and support the circle gear. Thus, the vertical position of the circle gear is not affected by the braking operation. A hydraulic circuit is provided to alternately operate the drive unit and the braking operation.

Abstract: A fluid cylinder having a tubular housing with a piston reciprocably mounted therein and capable of fluid pressure actuation in opposite directions. One side of the piston carries an actuating rod which slidably extends through one end of the tubular housing, while a coaxially aligned bore extending from the opposite side of the piston and into the actuating rod has a threaded surface adapted to receive a threaded member which, in turn, is rotatably carried at the other end of the tubular housing. The threaded surfaces of the piston bore and the rotatable threaded member engage in a self-locking relationship such that the piston is incapable of movement when subjected to fluid pressure unless the threaded member is initially and continually rotated. Means are provided for selectively rotating the threaded member upon fluid pressure actuation of the piston in either direction.