Abstract: A hydropneumatic pumping arrangement comprising at least two double-acting hydropneumatic force multipliers, pneumatic chambers of pneumatic cylinders of the multipliers communicating, through two two-position directional valves with an air source, and the chambers communicating through hydraulic non-return valves, with hydraulic pressure and return lines connected to actuating hydraulic cylinders of the associated processing equipment. The valves are cylindrical slide valves, an inlet passage of one slide valve is in communication with an air source and outlet passages are in parallel communication with the pneumatic chambers and with control chambers of another slide valve, outlet passages thereof being in communication with the control chambers of the one slide valve of the other force multiplier for alternate communication of the pneumatic chambers of both multipliers with the air source in the course of travel of the pistons of the pneumatic cylinders thereof.

Abstract: A control system for plural motor driven pumps is disclosed. The control system includes a control valve which provides for unloading one pump by diverting the flow of operating fluid from that pump back to reservoir whenever the flow through the valve or the load pressure exceeds a preselected level.

Abstract: The novel arrangement of prime movers and associated driven pumps in cooperation with a hydraulic summating system disclosed in this application consists of a plurality of prime movers, each of which is connected to drive a group of interconnected fixed displacement pumps. Separate sets of pumps are formed with one pump of each driven group connected in parallel to supply fluid under pressure to separate systems containing various hydraulically operated functions. The summating system includes a valve arrangement whereby the total engine power generated by the prime mover of each group of pumps is available for one or all pumps in the group and thus any one or all of the hydraulically operated functions in each system has available all or a portion of the prime movers' total engine power up to the maximum available.

Abstract: A pump assembly having at least two variable displacement pumps each having a separate pump control assembly are interconnected for control in response one to the other. Each pump control assembly has first and second biasing means acting on a respective swash plate. The first and second biasing means have interconnecting fluid pathways formed through a pump control housing. Means are provided within the housings for modifying the discharge pressures of the separate pumps to provide a resultant pressure signal for controlling the second biasing means.

Abstract: A hydraulic arrangement for turning the rotor shaft of an axial flow elastic fluid turbine rotor. The arrangement includes a variable speed hydraulic motor, the torque produced thereby being dependent upon the pressure of motive fluid supplied therethrough. The motor is connected through suitable coupling or clutch to the shaft. A plurality of sources of motive fluid each at a predetermined pressure range are connected to the motor. A flow control arrangement for selectively introducing motive fluid from each of the plurality of sources to the hydraulic motor to provide the desired torque output from the motor is provided.

Abstract: A fluid system of work elements of a work vehicle has first, second, and third fluid circuits each having a pump connected to a work element through a control valve assembly that is operated by a pilot pump. A fluid control means is provided for controllably combining fluid from each of the circuits with another one of the circuits.

Abstract: A hydrostatic transmission vehicle which is direction controlled by a speed controlled running assembly known as a motor-director running assembly and which has at least one further speed controlled driving running assembly. The motor-director running assembly is pivotable by means of a direction control system and its speed control system is coupled with that of each driving running assembly so that a speed which is coordinated with each driving running assembly is automatically applied to the motor-director running assembly when the vehicle is travelling in a straight line or turning.

Abstract: A hydraulic control system is disclosed for selectively directing fluid to a pair of reciprocable jacks connectably disposed intermediate a frame and an implement such as a bulldozer blade for tilting and tipping the blade relative to the frame. The control system includes a fluid supply source, a flow divider valve which is in fluid communication with the supply source for providing equal flow to a pair of outlet paths, a first control valve arrangement for selectively communicating fluid from one of the outlet paths to either end of one of the jacks, and a second control valve arrangement for selectively communicating fluid from the other one of the outlet paths to either end of the other one of the jacks.

Abstract: A hydrostatic unit of the type contemplated by the present invention includes one or more pump and motor combinations interconnected by means of a conventional closed loop. Controls for the hydrostatic unit include a speed control and vent valve assembly as well as a venturi manifold which functions to normally establish a selected pressure differential in a pair of supply conduits for determining instant operating conditions for the transmission. In order to automatically regulate displacement of each pump unit in response to prime mover speed, an underspeed actuator valve unit includes a piston which is hydraulically responsive to the differential pressure in order to adjust operation of a lever which controls displacement of the pump unit. A part throttle control valve prevents the underspeed actuator from reducing displacement of the pump unit when speed of the prime mover is reduced by a manual throttle control.

Abstract: The invention is concerned with an improved mechanical arrangement for controlling the steering and speed function of a hydrostatic control system for a ground driven vehicle. Such a control system comprises a pair of hydrostatic pumps each controlled by a rotatable arm extending from a servo valve mounted thereon along with a pair of hydrostatic motors each driven by a respective one of the pumps and a pair of ground engaging means each on respective sides of the vehicle.

Abstract: A fluid system of work elements of a work vehicle has first and second fluid circuits each having a pump connected to a work element through a control valve assembly that is operated by a pilot pump. A fluid control means is provided for controllably passing fluid between the first and second fluid circuits in response to control signals passing between said circuits.

Abstract: Apparatus of a fluid system of a work vehicle for controlling the fluid delivered to work elements of the vehicle in response to the load exerted on the fluid system by the work elements.

Abstract: Two adjustable-stroke pumps are driven off a common drive shaft and supply fluid to respective consumers via respective control valves settable by the user of the system. Each pump is provided with its own pressure regulator operative for regulating the output pressure of the respective pump by automatically adjusting the setting of the stroke-adjustment member of the pump. Transducers generate first signals indicative of the settings of the stroke adjustment members and second signals indicative of the settings of the control valves. A control arrangement maintains the settings of the volume-adjustment members in correspondence with the settings of the control valves by automatically altering the operation of the pressure regulators in response to discrepancies between the settings indicated by the first and second signals.

Abstract: An improved fluid system of a crawler type vehicle has control means for selectively passing fluid in a preselected sequence to a plurality of work elements.

Abstract: Fluid is selectively, controllably delivered at substantially common rates from separate respective variable displacement pumps in response to a load pressure signal acting on a single pump control valve serving said pumps.

Abstract: Apparatus of a fluid system of a work vehicle for controlling the fluid delivered to parallel work elements of the vehicle in response to the load exerted on the fluid system by the work elements.

Abstract: A fluid system for work elements of a work vehicle has first and second fluid circuits each having a pump connected to a work element through a control valve assembly that is operated by a pilot pump. A control means is provided for controllably passing fluid between the first and second fluid circuits in response to power demands of said circuits.

Abstract: A charge pump augmenting device includes a jet pump, powered by fluid flow from a main pump, to draw fluid through a check valve from a reservoir to supply additional fluid to the main pump when the charge pump supplying the main pump is inadequate to meet the demands of the main pump.

Abstract: A dual hydraulic motor drive system is provided for powering a material loading elevator of a self-loading scraper vehicle. Such drive system includes a pair of hydraulic motors which are disposed in a fluid circuit having a blocker valve movable between a first position to direct fluid pressure to just one of the motors to provide high speed, low torque operation of the elevator and a second position to direct fluid to both of the motors to provide low speed, high torque operation of such elevator. Actuator means responsive to loading resistance affecting the elevator being effective to automatically position the blocker valve in its first position during normal loading conditions and to shift it to its second position when severe loading conditions are encountered so as to prevent stalling of the elevator.

Abstract: A cascade drive system is disclosed for use in processes that deal with continuous lengths of material such as film, wire, paper, fabric, etc. The system includes a plurality of stages holding fixed speed ratios to each other; and uses hydraulic components arranged in a series flow circuit, in such a way that the line speed may be synchronously increased or decreased and individual ratios between adjacent stages may be changed.

Abstract: An oil hydraulic motor is provided with a casing in which a rotor is disposed in an eccentric position. An oil having a preselected pressure is sealed in the chambers defined between the rotor and the inner wall surfaces of the chambers and a high pressure is intermittently propagated into said chambers from a high pressure generating device with which it is in communication thereby rotating said rotor to develop an output.

Abstract: The disclosure relates to plural, motor driven hydraulic pump circuits, including circuits having the pumps in at least one circuit operated in pairs with all pumps being driven by a single prime mover. A speed responsive control device unloads one pump in one circuit when engine speed drops below a predetermined value without regard to the source of the condition causing the slowdown. Also included is a crossover means for sensing the pressure in aother circuit for preventing reloading of the unloaded pump when speed rises above the predetermined value unless and until the pressure including the pressure sensed in the other circuit is below a predetermined pressure.

Abstract: An improved automatically shiftable direction control valve for a tractor hydraulic system wherein there is provided a charging pump, low pressure priority functions such as cooling and lubrication connected to the charging pump, a main pump, a continuously acting reversible function, a single-acting function, and a double-acting function all connected to the output of the main pump, and a manually operable direction control valve for each of the functions. The improved automatically shiftable direction control valve has a restricted passage causing a pressure drop which shifts the valve so as to direct the exhaust of the continuously-acting and double-acting functions to the charging circuit and to direct the exhaust of the single-acting function to the fluid reservoir.

Abstract: A control system comprising an actuator having a fluid responsive member movable in at least first and second directions and two sources for controlling the fluid responsive member. A first of these sources includes a servo pump which pumps fluid from one side of the fluid responsive member to the other to thereby control the position of the fluid responsive member. A second of these sources includes a valve which controls the supply of fluid under pressure to the fluid responsive member and the return of fluid from the fluid responsive member. The servo pump and valve are arranged in parallel with their flows being summed at the actuator.

Abstract: A first pump and a second pump have respective mechanical inputs and are operative when the mechanical inputs are driven at constant speed for pumping fluid at an adjustable volumetric flow rate and at a constant non-adjustable volumetric flow rate, respectively, the maximum volumetric flow rate of the first pump being at least as great as that of the second pump. Connecting conduits connect the first pump in hydraulic circuit with an hydraulic consumer. An adjusting mechanism is provided for adjusting the volumetric flow rate of the first pump. A control arrangement is provided for bringing the second pump into and out of hydraulic circuit with the consumer in dependence upon the operation of the adjusting mechanism.

Abstract: A hydraulic system for pipelayers includes a first circuit with a pump and a motor for controlling a boom and a second pump and motor for controlling a hoist with pressure-responsive control means responsive to a first pressure for permitting combining of fluid for operation of the hoist and responsive to a second pressure for preventing combining of said fluid.

Abstract: A fluid operated reciprocatable device has an outer, usually fixed, member nd an inner relatively movable member joined by a resilient member e.g., of rubber. The outer member is closed at one end so as to form an enclosure into which fluid under pressure can be admitted so as to displace the inner member in a given axial direction relative to the outer member. When a pulsating pressure is applied to the fluid the inner member vibrates axially in accordance with the pulses. The resilient member is proportioned so that its dimension in the axial direction is large in comparison with the thickness between the outer and inner members, e.g. 4 times larger. The properties of the resilient member are chosen so that it acts not only as a seal between the outer and inner members to contain fluid, but as a return spring whereby the inner member is returned, between fluid pulses, from an axially displaced position.

Abstract: A hydraulic system having a plurality of hydraulic motors operated by fluid from a common reservoir includes means for circulating a flow of fluid from the reservoir through the housing of the motors to thereby maintain a substantially equal temperature between the motors and the fluid.

Abstract: A fluid feed device comprising a constant cylinder capacity pump and at least one variable cylinder capacity pump driven from a single prime mover, the variable cylinder capacity pump being provided with a regulator for reducing its cylinder capacity as the feed pressure increases. The regulator is such as to reduce the power absorbed by the variable cylinder capacity pumps as the pressure increases by an amount equal to the increase in the power absorbed by the constant cylinder capacity pump such that the total power absorbed by the pumps remains constant and equal to the power of the prime mover.

Abstract: In a preferred embodiment, there is provided in series with one-another a plurality of the basic motor unit of the present invention, the basic unit including one or more electric motors in parallel for driving a hydraulic compressor feeding a piston cylinder provided with a piston shaft extending axially along the longitudinal axis of the piston cylinder for reciprocatable motion of the piston shaft which at the distal end thereof is connected to a rotary crank and by the reciprocatable motion revolves the crank to impart rotary motion to the gears of a gear box drivable of the gearbox output rotary shaft having an appropriate clutch and a take-off pulley driven by the rotary shaft, and further driving a next-occurring hydraulic compressor of a next basic motor unit in the series.

Abstract: A motor-pump unit is used in combination with an existing hydraulic power transmission system to create an additional or auxiliary hydraulic power circuit.

Abstract: A hydraulic pump arrangement and control circuit for supplying fluid at high volume and high pressure to a work circuit. The system utilizes a fixed displacement pump, a variable displacement pump with a compensator, and a relief valve at a pressure setting higher than the variable displacement pump's compensator setting.

Abstract: A hydraulic backhoe utilizes two pairs of hydraulic pumps to power independent crawler track drives in any forward or reverse direction, and high or low speed ranges; allowing, for example, a wide arc turn either left or right, forward or backward. Through a novel hydraulic circuit, these pumps also power other functions such as boom, bucket and stick drives in high speed or low speed modes. This flexibility is accomplished by the use of a manually controlled track speed selector valve, an unloading valve and check valve between a track function valve and another function valve in each of the two hydraulic circuits. Full hydraulic pressure is available to all functions at all times except when a track drive is in high speed range. Conventional high-low or unloading operation of the other functions is had when the related track drive is not operating.

Abstract: Power is transmitted between reciprocating crank drives by piston, pump and motor assemblies of the single-acting type interconnected in an open fluid circuit. A valve arrangement in the fluid circuit maintains the pump assembly and the pressure conduits interconnecting the assemblies completely filled with fluid during the return strokes of the pump and motor assemblies.

Abstract: A fluid pressure system having a plurality of pumps, valves, and fluid-pressure responsive units. These items are interconnected by fluid lines, and check valves are arranged to control the fluid in only certain directions in some portions of the lines. The entire arrangement permits the utilization of one pump for a respective fluid-pressure responsive unit, or all of the pumps can be directed to one of the fluid-pressure responsive units.

Abstract: A closed loop hydraulic control system for a piston type fluid actuator maintains an average pressure on the piston during all operating conditions of the actuator. The system includes a first pump which controls the actuator and a makeup pump which supplies additional fluid to compensate for fluid losses in the system. An average pressure maintaining valve sums the fluid pressure on each side of the actuator and supplies additional fluid from the makeup pump to maintain a predetermined average pressure on the actuator piston.

Abstract: A hydraulic pressure amplifier with a scavenging pump operable to establish a negative return line pressure to effect a positive and rapid return of the rod of a one-way hydraulic actuator and thereby eliminate the necessity of third line-type systems that depend on gravity and/or spring-loaded actuators to return the hydraulic fluid to the tank.

Abstract: A motor is to be driven from a source of high-voltage electric energy, and a generator is adapted to produce a lower-voltage electric energy. A hydraulic stepdown arrangement is provided which drives the generator from the motor and which includes at least one closed hydraulic circuit having a conduit loop, a plurality of hydraulic pumps of successively greater capacity which are driven by the motor, and a fluid-driven rotor coupled with the generator for driving the same. The rotor receives the combined fluid output of the hydraulic pumps. Other drive systems are also disclosed.

Abstract: Flow sensing and control apparatus is provided to selectively combine the fluid output of an auxiliary pump with a hydraulic system. The apparatus includes a valve body having a primary pump passage therein through which fluid from one of a pair of primary pumps is conducted to its respective inlet of a control valve, an auxiliary pump passage interconnected between the auxiliary pump and the primary pump passage and a fluid receiving passage which is connected to the auxiliary pump passage. A pilot operated valve is disposed within the fluid receiving passage and operative in response to fluid flow through the primary pump passage for selectively controlling fluid to the fluid receiving passage so as to permit the combining of any available fluid from the auxiliary pump with that of the primary pump up to a predetermined minimum flow rate through the primary pump passage and for diverting any excess fluid from the auxiliary pump to the receiving passage above that necessary to maintain the minimum flow rate.

Abstract: A hydrostatic vehicle drive system having a closed loop front wheel drive circuit and a closed loop rear wheel drive circuit with bi-directional pressure compensating crossover flow between the two closed loop circuits. Another hydrostatic circuit for driving auxiliary equipment also operates as a source of pressurized fluid for charging the wheel drive circuits. The auxiliary hydrostatic circuit includes priority flow to the auxiliary equipment and a flow control with pressure relief means to maintain a constant charging pressure and a predetermined fluid flow for operating the braking circuit as well as charging the wheel drive circuits.

Abstract: A draft control valve for use with two constant displacement pumps in an open center hydraulic system. The valve controls the implement position in response to the draft loads and manual control and normally employs pressurized fluid from a low volume pump for operating in response to draft load sensing for control the implement position and employs pressurized fluid from the high volume pump for relatively short periods of time for positioning of the implement in response by the operator and extreme draft loads.

Abstract: A pair of hydraulic motors are operatively drivingly connected to a common rotatable member and are employed for transmitting power thereto from a pair of prime movers. A first hydraulic circuit communicates with one of the hydraulic motors and includes a pump driven by one of the prime movers while a second hydraulic circuit communicates with the other of the hydraulic motors and includes a fixed displacement pump and a variable displacement pump driven by the other prime mover. A device associated with the variable displacement pump is responsive to fluid pressures in the first and second hydraulic circuits for automatically varying the output displacement of the variable displacement pump so that a predetermined relationship is maintained between the fluid pressures in the first and second hydraulic circuit.

Abstract: A hydraulic filtering and reservoir means to accommodate changing rates of hydraulic fluid flow through a variable displacement pump. A constant displacement pump and a variable displacement pump are used in the system to provide filtered pressurized fluid for hydraulic motors.

Abstract: A fixed platen is supported in the machine frame, and a movable platen is connected to two parallel rods which project rearwardly through the fixed platen. Each rod carries a first piston and each piston is slidably received in a first cylinder. These cylinders are slidably received on the rods and each cylinder has a forward end defining a second larger piston slidably received in a fixed second cylinder. The front and rear faces of the smaller pistons are selectively connected to fluid from a first pump through a synchronizing valve, and a paralleling pump supplements the flow from the first pump during synchronization, that is during the major part of the mold opening and closing movement. Slower movement is provided for just prior to the platen reaching the mold open and closed positions.

Abstract: A pressurized fluid supply apparatus comprises a closed circuit including a variable delivery pump, an open circuit including a pump, a fluid reservoir and a fluid cooler, and an engine for driving said pumps having an output shaft coupled to the drive shaft of said pumps, a flow-limiter being provided in the delivery conduit of said pump of said open circuit and including a restriction whose configuration is independent of the pressure of fluid in said delivery conduit upstream of said flow-limiter.

Abstract: An apparatus and method for operating an auxiliary hydraulic load at low noise levels. A pump having a capacity which is sufficiently large to supply the load with the necessary volume of hydraulic fluid at relatively low pump speeds is driven by an engine operating at a speed near its idling speed. Throttle control means control the fuel supply to the engine at a level sufficient to drive the pump while maintaining the engine speed near its idling speed. When the engine speed is increased to a predetermined level in excess of its idling speed, means are provided to maintain the output from the pump at or below a predetermined flow rate to not overload the pump means or the auxiliary load. The pump may include a variable displacement pump or a plurality of fixed displacement pumps with means to vary the pump output in response to the pressure demand from the auxiliary load to maintain the torque input requirements for the pump below a predetermined level.