Abstract: A load sensing hydraulic system is disclosed of the type in which a load signal is communicated from downstream of a main flow control orifice to a device which is operable to vary the fluid delivery rate in response to changes in the load signal. Disposed in the load signal conduit is a load signal modulating valve which, in one position, communicates the load signal, substantially unchanged, to the variable fluid source. In another position of the modulating valve, the load signal chamber of the variable fluid source is drained to tank, while in intermediate positions of the modulating valve, a portion of the load signal is communicated to the variable fluid source, and a portion is bled to tank. Modulation of a load signal permits flow control in an hydraulic system, independent of the position or movement of the main spool valve. The input to the modulating valve may be manual or electric, and if electric, may be remote, or may be automatic in response to certain predetermined system conditions.

Abstract: A pumping unit for a well pump has a surface main cylinder with a main piston reciprocable therein, the piston having a connection to a standard well pump. In a flow cylinder of a relatively large diameter, a flow piston reciprocates within and divides the flow cylinder into a first flow chamber and a second flow chamber. The first flow chamber is in communication with the main cylinder. Air under pressure substantially to counterbalance the load on the well pump connection is supplied to the second flow chamber. There is a drive cylinder divided into a first drive chamber and a second drive chamber by a drive piston connected to but substantially smaller in diameter than the flow piston.

Abstract: The invention provides a device for extracting energy from waves on a liquid, the device having a chamber with an opening for the flow of liquid into and out of the chamber to provide a quantity of the liquid which is arranged to oscillate in the chamber to provide energy from these oscillations. In order to maximize the energy absorption efficiency of the device, that portion of the device to be submerged and lie in a vertical plane aligned in the direction of propagation of the waves is of asymmetric shape, and the device is arranged to be held in a manner to inhibit movement of the device itself in response to the waves.

Abstract: A primary pump drive for automatic motor vehicle transmissions, in which the primary pump is adapted to be driven directly from the input and is arranged with its axis parallel to the input axis. The pump is constructed as an internally toothed pump and its internally toothed wheel is provided with teeth at the external circumference thereof, into which engage the teeth of a gear connected with the input.

Abstract: A power transmission including a motor, a "fixed-fill" fluid coupling and a gear box, at least the "fixed-fill" fluid coupling of which is liquid cooled.

Abstract: The invention relates to a hydraulic brake booster for a vehicle brake apparatus which is provided with a pressurizing apparatus which has a pump and a reservoir (accumulator). When the reservoir pressure fails, a switchover piston which is subject to the reservoir pressure can disengage a stop for the push rod of the control valve.The push rod is supported on the stop when the pressure supply to the reservoir is intact and after the control valve switches over in the direction of brake activation.In this manner, a stop for the brake pedal, which activates the push rod is formed which is subject solely to the resiliency of a travel-limiting spring. The stop operates when reservoir pressure is available to effect a longer pedal stroke. When the reservoir pressure fails, it is automatically disengaged.

Abstract: A hydraulic control system is provided including a fluid reservoir, a variable displacement pump having a fluid input in fluid communication with the reservoir and having a fluid output, and a fluid actuated displacement control mechanism for controlling the displacement of the pump. A control valve is placed in fluid communication with the fluid output of the variable displacement pump and with the reservoir and is adapted to control the flow of fluid to a fluid actuated device. The control valve includes means for developing a control pressure signal.

Abstract: A readily portable hydraulic power source for supplying hydraulic fluid pressure to emergency hydraulic tools is foot-operated such that the operator's hands are left free to use the hydraulic tools and both the tools and power source may be operated by a single person. The power source includes a generally planar base member, a hydraulic pump fixedly mounted at one end of the base member, a foot-engaging planar member in generally overlying relation to the base member, a hinge connecting ends of the base member and the planar member for movement of the planar member relative to the base, and a resilient spring between the base and planar members to urge the members pivotally apart upon release of pressure from the operator's foot. The operator's foot is retained by straps and a heel retaining portion attached to the planar member, with the heel portion having an arm operatively connected to a hydraulic piston of the pump.

Abstract: A hydraulic circuit for steering and front brake system of a vehicle wherein discharged hydraulic fluid from steering cylinders is utilized for cooling front disc brakes. The circuit comprises a conventional steering circuit including a pair of steering cylinders and a steering valve having a drain circuit connected therewith, the pair of steering cylinders being operatively connected with the steering valve, and a pair of disc brakes for front wheels wherein the disc brakes are connected with the drain circuit of the steering valve.

Abstract: A gearless split torque (mechanical/hydrostatic), twin range (reduction/overdrive) with a direct mechanical drive in-between, hydrostatic transmission with regenerative braking and engine starting capabilities comprising two hydraulic pumps tied together by a clutch.

Abstract: A gearless split torque (mechanical/hydrostatic), twin range (reduction/ overdrive) with a direct mechanical drive in-between, hydrostatic transmission with regenerative braking and engine starting capabilities comprising two hydraulic pumps tied together by a clutch.

Abstract: A supply or demand margin valve for use in hydraulic systems having at least one load provided with hydraulic fluid under pressure by a main pump, a pilot pump and at least one control valve for the load. The margin valve includes a valve body having a bore with a spool reciprocally received within the bore. A first port in the body extends to the bore and is adapted to be connected to the pilot pump. A second port in the body extends to the bore and spaced in relation to the first port and is adapted to be connected to a component of a hydraulic system other than a pilot pump. A spring is disposed in the valve body for applying a biasing force to the spool to urge the spool in one direction and a third port is in fluid communication with the pressure responsive surface and is adapted to be connected to a main pump so as to apply a force to the spool to urge the spool in the same direction as the spring.

Abstract: A vehicle drive system including a rotary output, variable displacement, hydraulic motor (22) adapted to drive a wheel or the like, a pump (10) for providing hydraulic fluid under pressure to the motor, a pressure control valve (30) connected to the motor for regulating the displacement thereof to achieve a desired system pressure and having a pressure responsive surface (34) receiving a signal representative of system pressure and a biasing spring (36) acting in opposition thereto. The invention contemplates the improvement wherein a variable, settable, pressure reducing device (60,106) is connected to the pump and to the pressure control valve to apply hydraulic fluid under reduced pressure to the pressure control valve in bucking relation to the system pressure signal.

Abstract: An improved hydraulic pump structure for hydraulic systems which require a plurality of rotary pumps has a pump casing assembly (20) consisting of a plurality of pump casing elements (23-29) which are fastened together in abutting relationship to define a first pump cavity (54) and a second pump cavity (55a) with aligned drive shaft holes (56-61) and a drive shaft (62-63) which is journalled in the holes (56-61) and carries a rotary pump member (76-77 or 80-81) in each cavity (54 and 55a). The casing elements (23-29) are manifolded to provide a first fluid inlet passage (82), a first fluid delivery passage (84) which terminates in a port in a fluid delivery end plate (29), a second fluid inlet passage (86) which has an entrance opening (H6) in the fluid delivery end plate (29), and a second fluid outlet passage (87) which terminates in a port in the fluid delivery end plate (29).

Abstract: A control system for stopping a hydraulic motor in a predetermined position comprises a valve connected in parallel across the motor, the valve having a closed position and an open position in which flow is via a throttle orifice. When the motor is being driven normally the valve is closed. When the main control regulator for the motor is moved to stop the motor, the valve is automatically opened to allow limited fluid flow through the motor during a slowing down phase. A detector senses when the motor is a predetermined distance from its desired stopping position, and moves the valve to its closed position. Overload valves are provided to prevent overpressures.

Abstract: An arrangement for controlling the operation of a fluid-displacement machine, such as a hydraulic pump or motor, which is equipped with an adjuster that adjusts the machine toward higher and lower throughputs in dependence upon the pressure of a control fluid acting thereon, includes a control valve which communicates the adjuster either with a high-pressure zone or with a low-pressure zone of a control circuit in different ones of its terminal positions. In addition thereto, the arrangement includes a pressure-limiting valve interposed between the low-pressure and the high-pressure zones of the control circuit. Both the control and pressure limiting valves are acted upon by the control fluid, the pressure of which is controlled by a common regulating valve.

Abstract: The control system has an adjustable flow-rate pump and a fixed flow-rate pump which is supplied with hydraulic fluid via a supply conduit. A first throttle is interposed in this conduit and produces first signals in form of pressure differentials in dependence upon variations in the rotational speed of an ungoverned combustion engine which powers the hydraulic drive, which signals trigger flow-rate adjustments of the main pump. A second throttle is also interposed in the supply conduit and produces second signals in form of pressure differentials in dependence upon variations in the load upon the hydraulic motor of the hydraulic drive, which signals trigger movements of the throttle flap of the internal combustion engine towards the open or closed position thereof.

Abstract: To permit mechanical override of an electrical command system to control deflection of the swash plate or eccentricity of an axial or radial piston pump, for example upon failure of the electrical control system, a group of valves 5-8 are connected to an electrical control unit 23 and an additional control valve 4, 4' with a manual control lever 18', 30' is provided, the deflection of the swash plate 1 or eccenter ring 28 of the pump being sensed by a position transducer 22 moved by a linkage which includes the manual control lever. In normal operation, the manual control lever is maintained by spring pressure to deactivate the control valve but, under emergency conditions, the manual control lever will operate the first control valve 4, 4' to admit hydraulic control fluid to position the swash plate, or eccenter ring, respectively, the consequent movement of which is fed back through the linkage to the manual control lever.

Abstract: A two speed valve and bi-directional motor system is provided having a pair of motors, means for delivering pressure fluid selectively to either side of said motors, a two speed valve means receiving fluid on one side of said motors to selectively direct the fluid to one or both motors to provide high or low speed operation thereof and flow sensing means automatically connecting the discharge from the motors to the one motor not receiving fluid when the two speed valve is shifted to divert all fluid to one motor so that fluid is recirculated through said motor.

Abstract: The invention relates to a power take-off arrangement, particularly a power take-off arrangement from an engine, comprising a pump including a fixed casing defining an annular liquid chamber, a rotor with a vaned annulus rotatable in said annular liquid chamber and intended to be rotated over a relatively wide speed range, a liquid inlet to said annular chamber, a liquid outlet from said annular chamber, a gate between said inlet and said outlet intended to allow passage of the rotor thereby while obstructing the flow of liquid along said annular chamber externally of the vanes of the rotor, and means for maintaining the liquid outlet from said pump at a substantially constant pressure at speeds above a predetermined speed within said speed range.