Abstract: A safety steering system to control torque rotation for boats having directable propeller outboard motors capable of pivoting about a vertical axis. An arm extending from the motor is connected to a flexible cable having two ends, a first end connected to a steering device and a second end connected to the arm. An actuator control valve interposed along the flexible cable is capable of locking the arm in a single position when no force from the cable is being exerted on the arm. The control valve has a valve body with a central bore therethrough and a first external port and a second external port in fluid communication with the central bore. A hydraulic piston-cylinder is connected between the end of the motor arm and a tab in the motor well. The hydraulic cylinder has a first chamber of confined liquid and a second chamber of confined liquid.

Abstract: A by-pass valve for servo-steering systems to turn off the working pressure in a cylinder chamber of a pressure medium cylinder, whose valve housing includes a valve connection adapted to be connected with the cylinder chamber, a valve connection adapted to be essentially pressure-relieved, and a valve seat for a check valve operatively connected between the two valve connections; the valve housing is thereby adjustable relative to the axis of a steering shaft for purposes of changing the position of its valve seat while the closure member of the check valve is thereby retained by springy means in its normal position closing-off the valve connections with respect to one another and is actuatable into its by-pass position connecting the valve connections with each other by way of a stem movable in unison with the closure member by way of a cam surface fixed for movement in unison with the steering shaft; the valve housing is thereby exclusively rotatable in relation to its valve housing axis but is immovably s

Abstract: A fluid flow control device suitable for controlling the flow of fluid between two chambers of a jack comprises a valve between each of the two chambers being controlled and a common chamber. The valves are controlled by pilot operated stops which, when retracted permit the valves to close fully but which, when extended hold the valves partially open. A source of make-up fluid can be connected to the common chamber, and the feed to the pilot valves can be tapped off the common chamber by way of a restriction. Alternatively, the pilot valves can be isolated from the common chamber and a separate source of pilot fluid provided. In this case, the common chamber can be permanently connected to a source of fluid under pressure which can be a fluid pressure accumulator.

Abstract: A self-responsive fluid means for anti-cavitation, such as when a fluid motor is rotating in a manner beyond that induced by the fluid pressure fed thereto, and thus the motor itself acts in the nature of a pump to produce a cavitation effect. Thus, there is a fluid motor, a valve controlling flow thereto, a pump, and an additional valve which directs the exhaust from the fluid motor and back to the motor itself, under certain conditions of operation, all to avoid the cavitation effect. The latter valve includes two fluid inlet openings and a movable closure which controls fluid flow to a fluid outlet opening; and pressure relief valve are incorporated in that valve and thus permit and control flow to the reservoir when pressure is at a certain magnitude.

Abstract: A hydraulic control assembly especially suited for operation of a fail-safe valve. An integral structure is provided having a pair of check valves disposed in passageways extending from one chamber of a piston operator to a hydraulic reservoir and the other chamber of the piston reservoir, and in a fluid line extending from a high pressure source. In a fail-safe valve, cavity pressure normally acts on the valve stem and provides the force which moves the valve to its close position. A spring is disposed in the second chamber of the piston operator and, in conjunction with any force resulting from internal cavity pressure on the valve stem, aids in closing the valve. The second chamber is equal or greater in volume than the first chamber so that all of the hydraulic fluid displaced from the first chamber during valve closing can flow into the second chamber. In this way, the hydraulic power needed to pump hydraulic fluid back to the reservoir is not effected by installed hydraulic system variations.

Abstract: A hydraulic actuator having two balanced area actuator pistons, each controlled by the movement of a primary servo sleeve to supply pressurized fluid from a pressure fluid source to one side of the actuator piston and to allow return flow from the opposite side of the piston. Piston movement is reversed by translation of the primary servo sleeve. A blocking valve is in each flow line between the servo sleeve and the cylinders in which each piston moves. A flow channel from the pressure fluid source applies pressure to the shut off valves to maintain the valves normally open for flow of control fluid to and from the actuator pistons. Means, operable upon loss of fluid pressure, are provided for closing the shut off valves to maintain existing pressure on both sides of the actuator pistons automatically to maintain reactive loads in each actuator half.

Abstract: A construction vehicle, such as a motor grader, comprises a work tool mounted thereon and adapted to be selectively moved by at least one double-acting hydraulic cylinder. A fluid circuit comprises a pressurized fluid source adapted to communicate fluid to the cylinder via a first control valve. A normally closed second control valve is operatively connected between a storage tank of the fluid source and the rod and head ends of the cylinder for exhausting fluid therefrom to the tank directly upon actuation of an independent actuation means. Opening of the second control valve will thus place the cylinder in a "float" condition of operation.

Abstract: In a vehicle, such as a motor grader, having a work tool operated by at least one hydraulic cylinder, the position of the work tool being controlled by a main control valve, and the work tool being placed in a float condition by actuation of a second control valve, the improvement wherein the operator may override the float condition by actuation of the main control valve.

Abstract: A hydraulic actuator comprising a pair of pressure oil chambers each of which has a cushioning port, the two cushioning ports being connected to each other through a cushioning means. The cushioning means includes a pair of cracking valves whose closing pressure is lower than its opening pressure and a pair of restricting means for restricting the flow of a pressure oil provided with regard to said cracking valves. This structure permits an output means for the actuator to be stopped smoothly as a result of fully absorbing the inertial energy that accompanies the output means.

Abstract: A power steering apparatus for a vehicle comprising: a hydraulic actuator for supplementing manual steering torque; a first valve means for controlling directions of pressure fluid supplied to the hydraulic actuator in response to manual steering; a second valve means for reducing the supplementing force of the hydraulic actuator by by-passing the pressure fluid; a vehicle speed detecting means for detecting the cruising speed of the vehicle; first switching means responsive to the vehicle speed detecting means for supplying electric energy to the second valve means when the cruising speed exceeds a predetermined value; and second switching means for decreasing electric energy supplied to the second valve means when the second valve means starts to by-pass the pressure fluid.

Abstract: In an earthmoving scraper a low volume, low pressure, pilot pump supplies fluid pressure to a pilot control valve which routes this fluid through bleed lines to a remote scraper control valve that operates the bowl jacks on the scraper from a separate source of pressurized hydraulic fluid. By manually varying the bleed rates of the output of the pilot pump with the spool of the pilot valve, proportion actuation of the control valve can be obtained through differential pressures in the bleed lines connecting it to the pilot valve. A safety valve connected in the bowl carry circuit supplies an alternate source of fluid pressure to the pilot valve if the pilot pump fails, ensuring positive fail-safe operation of the system.