Abstract: A variable displacement apparatus includes a pair of axially adjustable housing parts sealingly joined together to form a unitary pumping chamber. A pair of meshing elongated vanes or gears having a plurality of teeth disposed within the chamber in a meshing overlapping relationship for positive displacement pumping purposes. The gears are mounted adjustably within the chamber to move axially therein as the housing parts are adjusted axially relative to one another.

Abstract: A discharge flow control system and method of a hydraulic pump driven by an engine for the minimization of the difference between a discharge mount of flow in the pump and total mount of operating oil necessary to operate each actuator in hydraulic equipment. The control system is provided with a detector which detects the number of rotation of the engine, generates equal number of pulses to the number of rotation, a detector which detects the tilt angle of a swash plate of the pump, a detector which detects the operating displacement of the actuator, a detector which detects the load pressure acting on the pump, and a controll unit which controls a target discharge flow mount of the pump which is suitable for performing a predetermined work based on the number of rotation, the tilt angle, the displacement and the load pressure.

Abstract: An axle driving apparatus is provided an includes a main casing, a cap plate coupled to the main casing along a first split line where the first split line is substantially disposed in a horizontal plane, and an axle cap coupled to the main casing along a second split line where the second split line is substantially disposed in a vertical plane. A center section is supported solely by the main casing and has connected thereto a hydraulic pump and a hydraulic motor where the center section is disposed offset from both the first split line and the second split line. A pump shaft is linked to the hydraulic pump and is supported by the main casing where the pump shaft has an axis disposed perpendicular to the horizontal plane and parallel to and offset from the vertical plane. A motor shaft is linked to the hydraulic motor and has an axis parallel to and offset from the horizontal plane and perpendicular to the vertical plane.

Abstract: In many hydrostatic systems, the variable displacement pump is controlled by an operator moving a directional control valve to provide pressurized fluid to the displacement changing mechanism thereof which in turn varies the displacement responsive to the degree of pressurized fluid being directed to the displacement changing mechanism. In order to insure that the displacement of the Variable displacement pump is at the desired displacement, various forms of follow-up mechanisms have been required. These follow-up mechanisms are many times complicated and expensive to add to the hydrostatic system. In the subject arrangement, the speed of the pump input shaft and the speed of the motor output shaft is sensed (R,S) and the signals directed to a microprocessor which in turn processes the signals and directs a control signal (P) to a solenoid operated proportional valve.

Abstract: A vehicle drive transmission includes a hydrostatic transmission (14) which comprises a hydraulic motor (16) of a variable displacement type. Swash plate (29) of this motor is displaced from its neutral position in one direction in a stepwise manner to plural angular positions. The motor is used for setting one of plural speed ranges or low-speed and high-speed ranges of vehicle within which vehicle speed can be changed in a non-stepwise manner by a hydraulic pump (15) having a non-stepwisely displaceable swash plate (28). Output shaft (18) driven by the motor is connected to rear wheels (2) for a constant drive thereof through a mechanical transmission mechanism (21) and to front wheels (1) for a selective drive thereof through a clutch mechanism (26; 126; 226). The clutch mechanism preferably includes a one-way clutch (85) for providing a selective drive mode in which front wheels are additionally driven automatically when slipping of the rear wheels is caused during the two wheel-drive condition.

Abstract: Upon detection of execution of operation for stopping a vehicle during its running state and of a drop in an actual speed ratio below a predetermined value, the actual speed ratio being the actual ratio of the revolution speed of an output shaft to the revolution speed of a power source, a feedback amount is determined, setting the integral component of the difference between a target motor speed ratio and an actual motor speed ratio to zero. Based on the feedback amount thus determined, an operation amount for controlling the angle of a swash plate is computed. With this amount, the angle of the swash plate is controlled.

Abstract: The invention relates to a hydrostatic travelling drive for a vehicle, having a primary-adjustable and secondary-adjustable hydrostatic driving gear, which comprises at least two hydraulic machines in the form of a hydraulic pump drivable by a drive motor of the vehicle and a hydraulic motor connected to the hydraulic pump by way of at least one operating line, both of which can be adjusted in their respective stroke volume in dependence upon a control signal changing with the load of the driving gear. To avoid disturbances of the secondary adjustment of the hydrostatic driving gear through momentarily or rapidly occurring fluctuations of the driving-gear load, as control signal for adjusting the hydraulic motor a travelling-speed signal generated by a sensor device and corresponding with the travelling speed of the vehicle is used which with increasing travelling speed effects a swinging-back of the hydraulic motor, i.e. an adjustment in the direction of its minimum stroke volume.

Abstract: The present invention, firstly, lowers the lower end of pump shaft to lower the belt transmitting mechanism to thereby provide the axle driving system for the integral hydraulic transmission matching with the running vehicle of lower floor system, which is concretely the L-like-shaped center section fixed within the axle casing, so that the upper surface of the horizontal portion of the L-like-shaped center section is used as the pump mounting surface 3b, the position of which is set lower than the fixedly junction surface of the axle casing. The present invention, secondly, provides the axle driving system which is capable of quickly putting the hydraulic transmission at the axle casing in the operable state when assembled. Concretely, at the center section in the axle casing are provided the second charge ports 3s and 3t which can manually supply operating oil into the closed circuit from the exterior of the axle casing.

Abstract: A first hydraulic circuit comprises a variable displacement hydraulic pump driven by a prime mover, a variable displacement hydraulic motor connected in a closed circuit to the variable displacement hydraulic pump, and a displacement control means for controlling a displacement of the variable displacement hydraulic motor. A second hydraulic circuit comprises a hydraulic pump driven by the prime mover, and drives a loader attachment. A displacement limitation means limits the maximum value of the displacement of the variable displacement hydraulic motor in accordance with a load pressure of the second hydraulic circuit. For example, the displacement limitation means reduces the maximum value of the displacement of the variable displacement hydraulic motor in proportion to the pressure in the second hydraulic circuit. The motor torque is controlled by directly adjusting the displacement of the motor, and a load of the hydraulic motor can thus be stably controlled.

Abstract: An integrated hydromechanical transmission capable of achieving continuous variability from maximum forward, through zero, to full reverse, and vice versa. The unit will achieve significantly higher rates of efficiency than current hydrostatic transmissions and, as well, has many other desirable characteristics. Intended for use in heavy-duty drive-wheel-steered and tracked vehicle applications such as hay windrowers, grain swathers, crawler tractors, military armoured vehicles, etc.

Abstract: A mechanical-hydraulic transmission gear system for use in construction vehicles or construction equipment and a method of controlling power transmission using the system arranged such that when a prime mover is rotating at high speeds, power transmission is effected only through a mechanical transmission gear to thereby reduce the power loss due to fluid pressure substantially to zero, while when the prime mover is rotating at low speeds power transmission is effected only through a hydraulic transmission gear so as to facilitate control of the speed of the vehicle and control of changing forward running over to reversing and vice versa.

Abstract: A hydraulic drive traveling system has a pressure compensated low control valve connected between a hydraulic pump and a variable displacement type hydraulic motor for controlling a flow rate of the hydraulic fluid supplied to the motor. The flow rate is controlled in accordance with the delivery pressure of the pump and demanded traveling speed of the motor. When the delivery pressure of the pump is at a high level, the motor is shifted to a first capacity. When the delivery pressure of the pump is low, the motor is shifted to either the second capacity or the first capacity depending upon the demanded traveling speed.

Abstract: A drive comprising a first group of cylinders of a radial hydraulic pump, rotating in relation to the drive frame about a first axis, and torsionally integral with the input shaft of the drive and with a housing inside which the first group of cylinders rotates; a second group of cylinders of a radial hydraulic motor, rotating in relation to the frame about a second axis; an output shaft, the axis of which is located between the aforementioned axes, and which is integral with a gear meshing with a gear integral with the housing in which the first group of cylinders rotates, and with another gear integral with the second group of cylinders; a mechanism for varying displacement of the first and second group of cylinders; and a distributing mechanism for alternately connecting the cylinders in the first group with those of the second group.

Abstract: A hydrostatic system includes a variable displacement hydraulic motor whose absorption volume is adjusted by a pressure regulator, depending on the rpms generated by the power source driving the system. The apparatus enables the variable displacement motor to fully utilize the drive power avaiable from the power source over a range of operating speeds.

Abstract: A method a braking a vehicle which has a drive motor, a hydrostatic drive unit including adjustable hydraulic machines having adjusting devices, and an electronic subassembly controlling the adjusting devices of the hydraulic machines. Continuous adjustment of the hydraulic machines permits the drive motor to exert a braking moment that slows the movement of the vehicle. The method includes rapidly adjusting the hydraulic machines by the electronic subassembly toward a setting that relieves the drive motor completely or partially after a limiting rpm value on the drive motor is exceeded and the higher pressure present in the hydrostatic drive unit reduces the braking energy through the adjusting devices until the speed of the drive motor drops below the limiting rpm value. At this time, the electronic subassembly again adjusts the hydraulic machines to utilize the braking moment.

Abstract: A hydrostatic driving gear is described comprising a primary unit rotationally driven by a driving engine and a secondary unit rotationally driving an actuator. Each unit comprises a variable displacement hydraulic engine, in particular an axial piston engine. They cooperate in an open circuit. The primary unit and secondary unit each have a displacement adjusting device and can be continuously adjusted in respect of their direction of displacement through a zero displacement center position in two directions of displacement. The displacement adjusting device of the primary unit has associated with it a pressure flow controller which holds the working pressure at a constant presettable value. The displacement adjusting device of the secondary unit has associated with it a speed of rotation detecting device, having a position sensor to detect the flow setting.

Abstract: The present invention is a neutral shifting mechanism for a hydrostatic transmission. A motor track ring has a groove and cam slot for receiving a control rod of the transmission, with the control rod having a cam portion for engaging the cam slot to lock the track ring in a position concentric with the pintle of the hydraulic motor, i.e. a neutral position. In the normal position, the cam portion positions the track ring eccentrically, allowing a speed control shaft to shift the hydrostatic transmission by pivoting the pump track ring about the control rod.

Abstract: A system and method for controlling the ground speed and enhancing the maneuverability of an off-road vehicle having systems for initially establishing and thereafter automatically returning the hydrostatic transmission to the neutral position, a pedal system interconnected with the neutral location and return system for selectively driving the vehicle in either the forward or the reverse direction, a brake system consisting of a left foot operated left and right turn brake subsystem which enhances the vehicles maneuverability, a right foot operated master brake system which is used to bring the vehicle to a complete halt and for emergencies, and a park brake system which is used to lock the brakes when the vehicle is at rest, a cruise control system which is interconnected with the pedal system and the brake system.

Abstract: A hydromechanical drive wherein a prime mover drives an input shaft which, in turn, can drive a coaxial output shaft by way of a clutch or transmission having one or more axial piston pumps. The pressure and/or rate of fluid flow in the pump or pumps is adjustable by one or more valves or by one or more tiltable wobble plates in response to signals from one or more adjusting devices which receive signals from an electronic control circuit. The latter further receives signals from tachometer generators which monitor the RPM of the input and output shafts, from a gauge which monitors the pressure in the pump or pumps, from the valve or valves, or from the adjusting devices(s) for the tiltable wobble plate(s).

Abstract: An HST type axle driving apparatus integrally assembling a hydraulic pump and a hydraulic motor at an HST type driving speed changing unit, in which a transmission casing, a pump casing and a motor casing are formed of soft metal material, such as aluminum cast, whereby mechanically processed portions are eliminated as much as possible and the manufacturing cost is reduced. A wall of the transmission casing that journals a motor shaft and a pump shaft, through which oil passages are perforated, is formed of hard metal material, such as cast iron. The parts of hard metal material are assembled by being enclosed by the casing of soft metal material.

Abstract: A system and method for controlling the ground speed and enhancing the maneuverability of an off-road vehicle having systems for initially establishing and thereafter automatically returning the hydrostatic transmission to the neutral position, a pedal system interconnected with the neutral location and return system for selectively driving the vehicle in either the forward or the reverse direction, a brake system consisting of a left foot operated left and right turn brake subsystem which enhances the vehicle maneuverability, a right foot operated master brake system which is used to bring the vehicle to a complete hault and for emergencies, and a park brake system which is used to lock the brakes when the vehicle is at rest, a cruise control system which is interconnected with the pedal system and the brake system.

Abstract: A fluid pressure control circuit for a working vehicle having a transmission operable by a fluid pressure and a negative type fluid pressure parking brake. The control circuit comprises a fluid pressure cylinder movable to a first end position to place the transmission in a low speed position and to a second end position to place the transmission in a high speed position, a fluid supply line for supplying pressure fluid to the cylinder, and a control valve mounted on the fluid supply line. The control valve comprises a three position valve having a first position to release the pressure fluid from the parking brake and the fluid supply line, a second position to supply the pressure fluid to the parking brake and set the cylinder to the first end position, and a third position to supply the pressure fluid to the parking brake and set the cylinder to the second end position.

Abstract: A hydraulic transmission apparatus comprises an input unit to which power from a power source is applied in a first direction, a direction changing unit hydraulically coupled to the input unit for extracting power in a second direction which is different from the first direction, and a case supporting the input unit and the direction changing unit. The input unit and the direction changing unit comprise an oil pump and an oil motor mounted respectively on one surface and another surface of the case. The case is filled with working oil for operating the oil pump and the oil motor.

Abstract: In a swash plate type hydraulic system such as a hydraulic pump, a hydraulic motor of the like, a group of cylinder bores in which plungers engaging a swash plate are slidably received are annularly arranged in a cylinder block, and higher and lower pressure oil passages are concentrically provided in the cylinder block. Further, a group of distributor valves are provided in the cylinder block in a radially arranged configuration for controlling the connection and disconnection between the higher and lower pressure oil passages and the group of cylinder bores by radial reciprocating motion of the valves, and an eccentric wheel is provided eccentrically with respect to the center of rotation of the cylinder block to abut against the outer ends of the distributor valves so as to impart a reciprocating motion to each of the distributor valves. A shifting device is provided for changing the eccentric relationship between the eccentric wheel and the cylinder block.

Abstract: A system and method for controlling the ground speed and enhancing the maneuverability of an off-road vehicle having systems for initially establishing and thereafter automatically returning the hydrostatic transmission to the neutral position, a pedal system interconnected with the neutral location and return system for selectively driving the vehicle in either the forward or the reverse direction, a brake system consisting of a left foot operated left and right turn brake subsystem which enhances the vehicle's maneuverability, a right foot operated master brake system which is used to bring the vehicle to a complete halt and for emergencies, and a park brake system which is used to lock the brakes when the vehicle is at rest, a cruise control system which is interconnected with the pedal system and the brake system.

Abstract: A power-transmitting system provides conservation of (speed) X(torque) product between an input shaft and an output shaft. It represents the equivalent of the power being transmitted through the system. This power is transformed into the form of incompressible fluid flow at high pressure by a volumetric pump coupled to the input shaft. This fluid flow is forced at that pressure into a volumetric motor. The fluid then pushes on pistons which are constrained by a fixed enclined track. The pistons are laterally guided in a rotor and radially arranged therein. The enclined track forms a closed curved surface which surrounds these pistons and the resultant of the reactions of the track surface on the pistons results in a torque being exerted on the rotor. The structure supporting the track surface is slidable in a manner such that the piston strokes are adjustable between zero and a set maximum.

Abstract: An agricultural tractor in which a transmission case comprises a front case portion housing a hydraulic stepless change speed mechanism and a rear case portion housing a gear mechanism. A partition wall is interposed between the front and rear case portions, and a tractor frame is secured to the partition wall by means of bolts.

Abstract: Engine BMEP being a major contributor to the gap between conventional automobile road fuel mileage and the theoretically possible, indicates the desirability of a continuously variable road wheel/engine speed ratio. There is described a double swash plate, regenerative, hydrostatic system, with a mechanical bypass. The two swash plates facilitate optimization of hydraulic parameters as well as engine BMEP and the rear one which is the primary controller permits modulation of regenerated energy in both directions, with optimum efficiency and facility.

Abstract: A hydrostatic hydraulic transmission has a casing which is connected to rotate together with an output shaft, and also has an input shaft. A pump includes a cylinder block, pistons reciprocable in the block, a valve plate, a swash plate and a yoke for the swash plate, the swash plate, the yoke and a valve plate being constrained to rotate together with the casing. The cylinder block is constrained to rotate with the input shaft. A motor has a cylinder block, pistons reciprocable in the block, a valve plate, a swash plate and a yoke for the swash plate, the swash plate, the yoke of the motor and the valve plate of the motor being constrained to rotate with the casing, the cylinder block of the motor being connected to a stator.

Abstract: The present invention is directed to a compact, lightweight and inexpensive hydrostatic transmission which in the preferred form has a variable displacement and reversible pump placed in side-by-side relationship with a fluid motor and wherein the transmission has a multisection housing with a uniform width center section forming both the pump chamber and the motor chamber. The fluid capacity of the pump and the fluid capacity of the motor are proportional to their widths and the ratio of the fluid capacity remains constant as various width center sections are used.

Abstract: An improved hydraulic auxiliary drive system for driving the normally non-driven wheels of a vehicle is disclosed. A variable displacement motor having a tiltable swash plate operable between zero and full displacement positions drives the normally non-driven wheels and a variable displacement pump supplies pressure fluid to the motor. A spring biases the swash plate toward its zero displacement position and a servo mechanism is connected with the swash plate for tilting the same. A first supply delivers pressure fluid to the servo mechanism to tilt the swash plate toward its full displacement position and a second supply delivers pressure fluid to the servo mechanism to tilt the swash plate toward its zero displacement position. The first supply includes a pressure control valve to control the pressure thereof.

Abstract: A hydrostatic propulsion system and method of operation is disclosed for smoothly driving a vehicle, such as a street sweeper. The system includes a shift lever for selectively moving a pump stroking valve into reverse, neutral, low forward, and fast forward speed positions to prepare the system. After the shift lever has been placed in a forward or reverse position, an accelerator pedal must be depressed to partially or fully close an inching throttle valve before the pump swash plate moves from its zero piston displacement position and begins to pump fluid to the hydrostatic motors. Hydrostatic braking forces are applied when the accelerator pedal is released and also in response to initial depression of a brake pedal for providing normal braking to the vehicle. Further depression of the brake pedal operates a conventional brake system for panic stops.

Abstract: An axial piston-type transmission in which a group of axially displaced pump pistons, that move in a cylinder block rotated by an input shaft, slidably engage one surface of a swash plate that rotates an output shaft. A group of axially displaced motor pistons, that move in a stationary cylinder block, slidably engage an opposite surface of the swash plate so that the plate is squeezed between the two groups of pistons. The swash plate is pivotally attached to the output shaft so that the angles between the two surfaces and the axis of rotation of the swash plate can be adjusted. The pump pistons and motor pistons are hydraulically connected in pairs. A rotary valve driven by the output shaft connects half the pump cylinders together hydraulically to form an output port and the other half together to form an input port.

Abstract: A hydraulic driven electric generator and air conditioning system for simultaneously generating controlled quality electrical power and producing air conditioning in a desired area has a variable displacement hydraulic pump for pumping a hydraulic fluid is driven by a prime engine means. The pump is hydraulically connected to a fixed displacement hydraulic motor which is powered by the fluid flow. The first motor drives an electrical generator means for generating electricity having a rotating blower fan mounted within a generator housing. A second hydraulic motor is hydraulically connected to the output of the first motor and is used to provide power to an air conditioning means. Means monitoring the passage of blower teeth of the rotating blower fan produces an electric output responsive to changes detected in the rotation of the blower fan.

Abstract: This invention is directed to a wobble-torque hydraulic transmission device which has variable forward and reverse speeds and is also provided with a straight-through drive feature. The device is provided with a coaster brake feature that prevents the device from running away when going downhill. Also, the device is provided with a brake assembly that prevents rotation of the piston-pump means during forward and reverse operation but permits rotation for straight-through drive.

Abstract: An automotive energy managing transmission comprising a differential for splitting the power to mechanical and hydrostatic branches. The transmission is adapted to operate in several modes: hydrostatic in the city, hydromechanical and mechanical on the highway, regenerative braking and engine starting. The transmission includes an energy storage means and allows the engine to operate intermittently during city driving.

Abstract: A hydraulic auxiliary drive system for the normally non-driven wheels of a vehicle to assist the main wheels. The auxiliary drive comprises at least one variable displacement motor having a swash plate for driving at least one of the non-driven wheels, a variable displacement pressure compensated pump supplying the motor with a constant pressure regardless of vehicle speed, a spring for biasing each motor swash plate toward zero displacement, a servo connected to the motor swash plate for varying the displacement of the motor, and a pressure source for supplying the servo. A manually operated pressure control includes a solenoid-controlled variable orifice for controlling the pressure level supplied to the servo to vary the torque output of the normally non-driven wheels. A control valve is positioned between the pump and motor for disengaging and reversing the auxiliary drive. Another embodiment includes a second servo connected to the motor swash plate for decreasing the motor displacement.

Abstract: The hydrostatic transmission control system includes a first and second two-position solenoid valve which function to alter the hydraulic fluid parameters as delivered to the servo control cylinders of a variable displacement pump associated with a hydrostatic transmission. Activation of the first solenoid valve instigates a varying of pump displacement. Once the desired pump displacement has been achieved, the second solenoid valve is activated to maintain the desired pump displacement. The deactivation of both solenoid valves results in the hydrostatic transmission seeking and maintaining a neutral mode.

Abstract: A hydromechanical/hydrostatic automotive energy management system comprising two hydraulic units, the system adapted to provide: An efficient, continuously variable optimal transmission ratio, an intermittent optimal engine operation in city traffic and regenerative braking, thereby, the system is able to reduce a car's fuel consumption by as much as one half while improving drivability.

Abstract: A drive train includes a hydrostatic transmission unit and a multiple speed range transmission unit arranged in series between a prime mover and a primary output shaft, variable displacement and torque transmitting capacity of the hydrostatic transmission unit being adjusted by hydraulic controls including a speed control valve for developing a differential pressure signal proportional to a desired rate of operation, a modulating valve for regulating the differential pressure signal corresponding to accelerating and decelerating operation of the transmission, a directional control valve for determining the direction of operation of the hydrostatic transmission unit, and a range selector valve for shifting the operating speed range of the multiple speed range transmission as the hydrostatic transmission approaches a limit of displacement, the displacement of the hydrostatic transmission being automatically reset in response to shifting of the multiple speed range transmission.

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 gearless split torque hydromechanical transmission with regenerative braking and engine starting capabilities comprising two hydraulic pumps tied together by a one-way clutch.

Abstract: For tractors or like machines which can be provided, upon assembly, with either a hydrostatic transmission or a mechanical stepped-speed transmission, a transmission housing having a removable cover is provided. The machine has a drive shaft and a driven shaft and, according to the invention, a hydrostatic transmission is mounted intact upon the cover for introduction into and removal from the housing with this cover. The hydrostatic transmission comprises an inclined-disk variable-displacement pump whose input shaft is connected to the drive shaft and a hydraulic pump of the drive-flange type hydraulically connected to the pump and having an output shaft which is, in turn, connected to the driven shaft.

Abstract: A hydraulic pump apparatus including an outer housing having internal walls which are spherically configured, a hydraulically actuable variable position control ring which cooperates with the spherical housing walls to define the geometry of a hydraulic working cavity, and a rotor assembly having vanes which divide the working cavity into a plurality of working chambers and which follow the position of the control ring to vary the volume of the working chambers so as to move fluid into and out of inlet and outlet ports, respectively. The vanes are supported by a plurality of concentric rings which are attached in gimbal fashion to a rotor hub and pin assembly.

Abstract: A control device for a driving unit which comprises an internal combustion engine and a hydrostatic vehicle transmission. The hydraulic adjusting members of the control unit are in response to a relief of pressure automatically by spring force moved to their starting position and are connected to a control circuit which is connectable to the pressure line of a constant delivery pump and is also by a control member connectable to a fluid return line for purposes of setting a control pressure. An adjustable measuring orifice of a limit load control is arranged in the above mentioned pressure line and, when looking in flow direction, is located ahead of the connection of the control member. The control member of the adjustable orifice is connected, for instance, to the gas pedal of the internal combustion engine. A check valve is arranged in a conduit extending from the limit load control to the control circuit of the hydrostatic transmission.

Abstract: A hydrostatic vehicle transmission with a primary and/or secondary part adjustable as to its delivery and its absorption capacity respectively. The hydraulic adjusting elements of said primary and/or secondary part are automatically by spring force adjusted in the direction toward their starting position and are connected to a control circuit which is adapted to be connected to the pressure conduit of a constant delivery pump and is also adapted for controlling the control pressure to be connected to a return line by means of a control member. An adjustable orifice of a limit load control is arranged in the pressure line, which orifice is arranged ahead of the connection of the control member when looking in flow direction. The adjusting member of said limit load control may for instance be connected to the gas pedal or manually operable gas lever of an internal combustion engine for instance a Diesel engine while the hydrostatic vehicle transmission also serves as vehicle brake.

Abstract: A hydrostatic transmission control for a hydrostatic transmission having a variable displacement pump and a variable displacement motor including pressure-responsive displacement control means for the pump and motor with a displacement control valve for each of the pump and motor and positionable by a control pressure to set the displacement of the pump or motor with which it is associated. In dual path control of two hydrostatic transmissions, a master circuit has a first valve for setting a control pressure to determine the speed of operation of the transmissions and a second valve for determining the direction of operation of the transmissions, with operation of both valves by a single control handle. The master circuit connects into two branch circuits, each leading to the displacement controls for one of the hydrostatic transmissions and with each branch circuit having its own steering control valve.

Abstract: In a central hydraulic system for marine deck machinery, fixed displacement hydraulic motors are utilized to drive anchor winches and standard mooring winches, and variable displacement hydraulic motors are utilized to drive automatic mooring winches. This permits individual regulation of the line pull or tension of the mooring line of each automatic mooring winch. Variable displacement pressure compensated over center pumps are utilized to supply hydraulic fluid for operating the hydraulic motors by means of a closed loop circuit, and charging pumps are utilized to supply hydraulic fluid at charging pressure.Infinitely variable volume pressure compensated pilot operated four-way directional valves are used to regulate the flow of hydraulic fluid from the variable displacement pressure compensated over center pumps to the hydraulic motors, thereby regulating the speed of operation of each hydraulic motor and the marine deck winch driven thereby.

Abstract: The application discloses a system which includes a prime mover driving a variable displacement type pump which in turn drives a variable displacement type motor all coordinated by a control system. Details of valves employed in the control system are disclosed as well as the overall interconnection of such valves with the engine, pump and motor. The control system controls the amount of fuel supplied to the engine, pump displacement, and motor displacement in such a manner as to achieve optimum performance.