Abstract: Two synchronous hydraulic polyphase motor-generators with axial cylinders are connected by rigid or flexible pipes. One functions as a generator, the other as a motor to transmit torque and power. Sinusoidal piston motion is developed without the use of cams. The pistons cause columns of fluid to alternate between motor and generator, producing synchronous rotation. Apparatus for synchronizing, coupling and decoupling the motive force are disclosed.

Abstract: A charge pump for a hydrostatic transmission, having a self-charge relief function, in which a first toothed wheel, a second toothed wheel, and a pump casing, housing therein the first and second toothed wheels, are molded of heat resistant resin material, thereby reducing the weight of the charge pump, stabilizing its charge relief function and reducing the wear of the lower surface of a center section.Check valves are housed in the pump casing so that operating oil sealed between a hydraulic pump and a hydraulic motor can always be kept in a proper amount, regardless of whether the charge pump is driven or not.

Abstract: An axle drive unit for facilitating maintenance, such as replacement or cleaning of an oil filter for filtering operating oil. The present invention uses the interior of the housing of the axle drive unit as an oil sump. The axle drive unit has a hydrostatic transmission for driving axles and operating oil supply means for supplying the operating oil to the transmission. A plug-in bore is open at the side wall of the housing opposite to a suction port of the operating oil supply means. The oil filter is inserted into the housing through the plug-in bore and connected to the suction port. The plug-in bore is covered with a cover member for freely opening and shutting the bore. Such construction enables a worker, when inspecting or replacing the oil filter, to remove the cover member from the side wall of the housing while the axle drive unit is being loaded on a vehicle. The oil filter can simply be inserted or removed through the open plug-in bore.

Abstract: A continuously variable hydrostatic transmission includes an input shaft connected to drive a hydraulic pump unit, a grounded hydraulic motor unit, and an output shaft. A wedge-shaped swashplate is pivotally mounted to the output shaft in driving connection to receive output torque resulting from the exchange of pressurized hydraulic fluid between the pump and motor units through ports in the swashplate. A hydraulically actuated ratio controller is pivotally linked to the swashplate to selectively adjust the swashplate angle relative to the output shaft axis and thereby change transmission ratio.

Abstract: The invention relates to a hydrostatic propulsion drive having a drive motor, of variable speed, for a hydraulic machine of a hydraulic transmission, a setting device for the displacement volume of the hydraulic machine, a device for generating a setting pressure proportional to the speed of the drive motor in a setting pressure line, a pilot valve in the setting pressure line which is coupled with the setting device and--dependent upon its though-flow position within a through-flow adjustment range of effective follow-up into the closed position--controls the volume of a pressure medium supplied to the setting device, and in a through-flow end position beyond the effective follow-up acts upon the setting device with the speed-proportional setting pressure.

Abstract: A continuously variable hydrostatic transmission includes axially aligned input and output shafts journaled by a transmission housing and respectively coupled to a prime mover and a load. The input shaft drives a hydraulic pump unit, while a hydraulic motor unit is grounded to the transmission housing. A wedge-shaped swashplate is pivotally connected to the output shaft in operative position to accommodate pressurized hydraulic fluid exchanges between the pump and motor units. A controller is coupled to adjust the angular orientation of the swashplate relative to the output shaft axis and thus set the transmission ratio. A hydraulic circuit, connected into the hydraulic motor unit, is selectively operable to vent high and low fluid pressure sides of the swashplate to atmosphere, thus imposing a neutral transmission ratio condition regardless of the transmission ratio set by the controller.

Abstract: An axle driving apparatus wherein a hydraulic motor and a hydraulic pump for a hydro-static-transmission are housed in a transmission casing of the axle driving apparatus and a center section for connecting the hydraulic motor and hydraulic pump is disposed in the transmission casing, the center section being fixed at the butt joint portion at the transmission casing, and an oil passage from the hydraulic pump to the hydraulic motor at the center section is bent at a right angle so as to extend the motor shaft in parallel to the axles, so that the rotation direction of the motor shaft conventionally changed by bevel gears is changed by the oil passages in the center section.

Abstract: A hydrostatic drive apparatus for transferring power from a light duty vehicle engine to an output axle, including a charge pump for providing additional hydraulic fluid to a hydrostatic transmission in the apparatus, wherein the charge pump is mounted external to the housing of the drive apparatus.

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: The forklift controller changes the speed of the actuator, corresponding to the operational angle of the lift lever, and then changes the vehicle speed, corresponding to the amount of depression of an accelerator. This allows the controller to control the throttle opening corresponding to the operational angle of the lift lever, and together controls the amount of depression of the accelerator. During running without being loaded, the forklift controller changes the vehicle speed, corresponding to the amount of depression of the accelerator, and together determines the number of revolutions of the engine to the throttle opening so that the optimum fuel consumption can be obtained. The controller controls the throttle opening and speed ratio so that the vehicle speed and number of revolutions of the engine can be controlled.

Abstract: A hydrostatic transmission constructed so that a check valve and a relief valve are made as compact as possible to supply oil to a closed circuit for connecting a hydraulic pump and a hydraulic motor, and to regulate maximum pressure in the closed circuit. A check valve and a relief valve are contained in a valve casing. A valve body of the relief valve is disposed opposite to a valve body of the check valve. A relief spring of the relief valve is retained by a cover detachably mounted to an open end of the valve casing, thereby facilitating pressure setting of the relief valve. The valve body of the relief valve is contained in a relief valve casing slidably disposed in the valve casing. A plunger, capable of urging the check valve in the opening direction via the relief valve casing, is provided in the cover, thereby enabling the check valve to be manually opened.

Abstract: Means for connecting auxiliary pumps and charge pumps to an axle driving apparatus to transfer power from a light duty vehicle engine to an output axle, wherein the charge and/or auxiliary pumps are mounted to the external housing for an integrated hydrostatic transmission or to the external housing for a hydrostatic transmission which is connected to separate axle mechanisms.

Abstract: Means for connecting auxiliary pumps and charge pumps to an axle driving apparatus to transfer power from a light duty vehicle engine to an output axle, wherein the charge and/or auxiliary pumps are mounted to the external housing for an integrated hydrostatic transmission or to the external housing for a hydrostatic transmission which is connected to separate axle mechanisms.

Abstract: A hydrostatic differential transmission includes a pair of cylinder housings (58, 62) rotatably mounted for free rotation on coaxial input and output shafts, respectively, with a first pivotable swash plate (101) and second fixed swash plate (24b) fixed to the input and output shafts, respectively and a differential. An adjustable control selectively pivots the first swash plate between a neutral position, where the swash plate is at an angle to the input shaft equal to the angle of the second swash plate to the output shaft, and a direct drive position, where the swash plate is perpendicular to the input shaft. The differential includes a forward ring gear (32) fixed to the input shaft, a rearward ring gear (30) fixed to the output shaft and pinion gears (38, 40) between the forward and rearward ring gears. The pair of cylinder housings rotate together (via 36, 96) and have the pinion gears rotatably mounted thereto, for driving an auxiliary pump (48).

Abstract: A continuously variable transmission includes a pump (258) driven by an input shaft (256) against a wedge-shaped swashplate (260). Hydraulic fluid pressurized in the pump flows through ports (402) in a pump cylinder block (422) into kidney-shaped slots (406) in the swashplate (260), and from there flows into and pressurizes a series of cylinders (394) in a motor cylinder block (366). The pump and motor exert first and second components of torque on a swashplate (260) in the rotational direction on the input shaft (256), and the hydraulic system pressure in the swashplate slots exerts a third component of torque in the same direction on the swashplate (260). The third torque component is a product of the hydraulic system pressure and the differential area of the two ends of the high pressure slot (406P) at the narrow and thick sides of the wedge-shaped swashplate (260).

Abstract: A hydrostatic machine which includes a housing having an internal space accommodating a rotatably journaled driving mechanism, and wherein the portion of the internal space which is not occupied by the driving mechanism encompasses a drain oil chamber which receives the drain oil inclusive of lubricating oil which is discharged from bearing locations of the hydrostatic machine, and which is connected or port to a tank through at least one drain oil connection of the housing and through a drain oil line.

Abstract: A clutch valve is constituted with a valve cylinder fitted in and fixed to the center of a cylinder block in a manner to form with the cylinder a third ring-shaped oil passage and a second ring-shaped oil passage to communicate with a first ring-shaped oil passage and a valve body slidably fitted in the valve cylinder in a switchable manner to communicate between the third and second ring-shaped oil passages and/or shut them off from each other.

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: In a valve mechanism for controlling oil pressure in an oil path (13) connecting between a hydraulic pump (11) and motor (12) of a hydrostatic transmission (10), a differential piston (23) serving as a relief valve member for gradually increasing the oil pressure has a larger pressure-applied surface area at the side opposite to the oil path than at the side of this path. A throttled oil passage (24) is provided for conducting oil pressure in the path to the larger surface area. The piston is biased by a valve spring (25) through a control piston (26). A receiving member (27) for the spring and a stopper member (28) for the control piston are provided such that they are adjustable in position independently of each other. By this, the manner of increasing the oil pressure may be adjusted in a large variety. The valve mechanism also serves as a relief valve for excluding a possible, excessively high pressure.

Abstract: A hydraulic power transmission including a compact external oil pressure takeoff apparatus which houses therein a hydrostatic transmission, and attaches thereto a charge pump. The transmission is capable of supplying operating oil and of taking out external oil pressure. Specifically, part of the discharge oil from the charge pump is adapted to be taken out from the housing so as to omit the need for an external takeout pump. An oil filter is disposed on the exterior of the housing, thereby facilitating maintenance of the hydraulic power transmission.

Abstract: A pilot-operated pressure relief valve is provided for a hydrostatic transmission. The override valve is in the closed circuit loop, which includes a pair of multi-function valves and a displacement control valve. The pressure override valve includes a spool slideably mounted within a body so as to be responsive to a pressure differential created by pilot flow through the override valve. The spool is biased to a normal position which provides fluid communication between a pressure charge source and the displacement control valve. As the pressure differential in the override valve increases, the spool shifts so as to close such communication from the charge source to the control valve, thereby defeating the pressure signal from the control valve to the servos of the hydrostatic transmission pump.

Abstract: The improved hydrodynamic variator of velocity comprises a pump (3) having radial pistons and a hydromotor (4) also having radial pistons. At least the pump is arranged with a variable eccentricity and there is provided a central body (56) the latter having frontal distributors (30 and 31) which are placed in communication with the radial cylindrical cavities respectively of the pump and the hydromotor by means of the openings of the conduits (32 and 33). By varying the eccentricity of the pump, the rate of flow of the liquid in the pump is varied, thus causing a variation in the number of turns of the hydromotor.

Abstract: A solenoid operated control valve in an automatic transmission is operated by dither current. A flow rate of oil through the solenoid operated control valve is calculated. At least either one of the frequency and amplitude of the dither current is corrected by the flow rate. The solenoid operated control valve is operated by the dither current.

Abstract: A hydraulic piston type motor having a rotating piston barrel abutting a fixed porting plate or head with a starting charge device including a differential area piston operating to supply a limited hydrostatic pressure between the porting plate and rotating barrel to reduce starting friction and improve starting torque.

Abstract: An infinitely variable differential hydrostatic transmission utilizing a fixed displacement pump/motor and a variable displacement pump/motor interconnected with appropriate valving, to provide a mechanical/hydraulic differential drive which is capable of achieving an overall efficiency in the 98.degree.-99.degree. range. In the preferred embodiment, which utilizes axial piston type pump motors, pistons in multiples of four are utilized in order that each piston will have a piston located 90.degree. from it to serve as its control valve. The fixed and variable displacement motor/pump are provided as an integral unit containing bearing mountings, cylinder barrels, valve ports, piston seal mountings, hydraulic flow passages, pressure reservoirs and manifolding by forming a series of individual segments and sealing them together into a single structural unit. A unique mounting arrangement is utilized to positively attach the pistons to an anti-friction swashplate which eliminates all side loads on the piston.

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: A hydraulic-motor drive circuit system includes an auxiliary hydraulic source connected to one end of an auxiliary line, a low-pressure selector connected to the other end of the auxiliary line and a pair of main lines for causing the other end of the auxiliary line to communicate with one of the main lines on the low pressure side during rotation of a hydraulic motor for driving an inertia load, and a switching control arranged in the auxiliary line for supplying the hydraulic fluid from the auxiliary hydraulic source to the other end of the auxiliary line when the directional control valve is in a neutral position, cutting off the hydraulic fluid from the auxiliary hydraulic source to the other end of the auxiliary line when the directional control valve is in an operative position.

Abstract: A charge pressure priority valve for supplying a flow of sufficient pressure to energize an auxiliary implement while supplying a nearly constant pressure flow to a hydrostatic fluid circuit includes a valve body having an interior bore with a pump inlet passage for communicating a flow from a hydraulic pump thereto. A main flow outlet passage extends from the interior bore for supplying fluid to the hydraulic fluid circuit and has a main flow feedback passage interconnecting the main flow outlet passage and the interior bore. An auxiliary flow outlet passage extends from the interior bore for supplying a flow of sufficient pressure to energize an auxiliary implement. A valve spool is disposed within the interior bore and defines a central chamber intermediate a pair of spaced apart end chambers in the bore, with one of the pair of end chambers being isolated from the other of the pair of end chambers.

Abstract: A power train for vehicles having a swashplate type continuously variable transmission having a swashplate hydraulic pump and a swashplate hydraulic motor, a transmission cylinder therebetween with a plurality of pump plunger holes and motor plunger holes formed therein. The transmission cylinder is rotatable about an axis and is coupled with the crankshaft of the engine. The pump swashplate is rotatable and disposed at an angle to the axis of the transmission cylinder and is coupled with pump plungers. A motor swashplate which is variably inclined relative to the axis of the cylinder and includes motor plungers associated with the cylinder.

Abstract: A hydraulically operated continuously variable transmission includes a hydraulic pump coupled to an input shaft, a hydraulic motor coupled to an output shaft, a closed hydraulic circuit interconnecting the hydraulic pump and the hydraulic motor, a hydraulic actuator for actuating a controlled member in the closed hydraulic circuit, an auxiliary pump connectable to the closed hydraulic circuit and the hydraulic actuator, a supply oil passage for supplying oil discharged from the auxiliary pump to the hydraulic actuator, and a control valve coupled between the supply oil passage, the closed hydraulic circuit, and an oil tank. The control valve comprises a hydraulic chamber communicating with the supply oil passage, a spring, and a spool disposed between the hydraulic chamber and the spring.

Abstract: A torque transmission apparatus has a hydraulic assembly with a variable speed control, and comprises first and second rotors at a power side of the transmission apparatus, the rotors being coaxially rotatable with respect to each other. The first rotor has a swash plate facing the second rotor. The second rotor has a plurality of cylindrical bores which have open ends facing the swash plate and other ends which are communicated with through bores arranged in communication with ports. Plunger members are provided for sliding in the cylindrical bores, the plunger members being guided by the swash plate. A control rotor and a stator are provided at a control side of the transmission apparatus. The stator has a swash plate, and the control rotor has cylindrical bores having open ends facing the swash plate of the stator and communicating with through bores in the stator. Plungers are provided which slide in the cylindrical bores of the control rotor, guided by the variable swash plate of the stator.

Abstract: A hydrostatic drive system consists respectively of an adjustable primary and secondary unit which are connected together via a conduit train with impressed pressure. The volume flow of the primary unit is regulated in dependence upon the impressed pressure and the volume flow of the secondary unit as a function of the speed. To avoid pronounced dropping of the impressed pressure the power of the secondary unit is limited. For this purpose a circuit is provided in which the volume flows of the primary and secondary units are compared. The power limitation intervenes when the volume flow of the secondary unit exceeds the volume flow of the primary unit.

Abstract: A single hydraulic pump (6) is employed in a vehicle for supplementing fluid to a hydrostatic transmission (1) and for supplying fluid to a fluid-operated clutch (2) and to high pressure-actuated hydraulic actuators (3, 4, 5). Fluid discharge path (7) of the pump is connected to the hydrostatic transmission through a pressure-reducing valve (8). Fluid drain path (9) of the reducing valve is fashioned to a fluid supply path for the clutch. A second fluid supply path (11) is connected to the discharge path for supplying fluid to the hydraulic actuators and include a relief valve (12) or orifice (12A) for maintaining fluid pressure in the discharge path higher than the output pressure of the reducing valve. A high pressure relief valve (10) for establishing fluid pressure to be applied to the actuators is connected to the discharge path for minimizing a discharge pressure required to the pump.

Abstract: In a hydrostatic continuously variable transmission in which a clutch valve capable of operating between a clutch-on position for setting a hydraulic closed circuit between a hydraulic pump and a hydraulic motor to a hydraulic transmitting state and a clutch-off position for setting the hydraulic closed circuit to a hydraulic transmission cutting-off state is connected to the hydraulic closed circuit, a pressure bearing chamber for urging the clutch valve to the clutch-off position, and a pressure regulating spring for urging the valve to the clutch-on position are provided in the clutch valve, and a clutch controller for regulating the set load of the pressure regulating spring is connected to the pressure regulating spring. Thus, the degree of the hydraulic transmission between the pump and the motor can be controlled as desired without influence of the viscous change of a working oil. The clutch valve is disposed at one axial end of a transmission shaft.

Abstract: In a hydrostatic continuously variable transmission comprising an annular inner oil passage and an annular outer oil passage which are formed in the cylinder block between a large number of cylinder bores in the pump cylinder and a large number of cylinder bores in the motor cylinder so as to surround an axis of the cylinder block, large numbers of first and second distributor valves disposed radiately in the cylinder block and adapted to be reciprocally moved radially of the cylinder block, and a first and a second eccentric ring engaged with the first and second distributor valves, respectively, a large number of clutch valves are arranged radiately and circumferentially alternatively with the second distributor valves in the cylinder block and adapted to be reciprocally moved between radially inner and outer positions in the cylinder block to short-circuit the oil passages when the reciprocation stroke thereof exceeds a given value.

Abstract: A hydrostatically operated continuously variable transmission for use with an engine includes a swash-plate-type axial-piston hydraulic pump and a swash-plate-type axial-piston hydraulic motor which are interconnected by a closed hydraulic circuit. The pump and motor cylinders of the pump and the motor are disposed coaxially with each other and integrally coupled to each other into a cylinder block. An input shaft connected to an engine is coupled centrally to the cylinder block, and a output tubular shaft connected to a load is relatively rotatably disposed on an outer periphery of the cylinder block. The pump swash plate of the pump is supported by a stationary machine frame. The motor swash plate of the motor is supported by the output tubular shaft.

Abstract: When a first rotating shaft is rotationally driven, it rotates a first cylinder barrel splined thereto, and a second cylinder barrel and a valve block united with the first cylinder barrel. In accordance with these rotations, first pistons in first cylinders slide circumferentially on the inclined face of a first swash plate so that they are reciprocated axially in the first cylinder barrel, and second pistons in second cylinders slide circumferentially on the inclined face of a second swash plate so that they are reciprocated axially in the second cylinder barrel. Simultaneously with these reciprocations, a first change-over valve is switched in accordance with the rotations of the first rotating shaft, and a second change-over valve is switched in accordance with the relative rotations of the first rotating shaft and the second rotating shaft.

Abstract: A variable displacement hydraulic pump and a hydraulic motor are connected in a closed circuit. A pressure oil supply means includes the variable displacement hydraulic pump and a tilting controlling means for controlling a tilt angle of the hydraulic pump and supplies an amount of pressure oil corresponding to the tilt angle of the hydraulic pump to the hydraulic motor. When rotation of a prime mover is detected by a rotation detecting means, an opening and closing valve is changed over to a first position in which the pressure oil supply means is permitted to supply pressure oil. When stopping of the prime mover is detected by the rotation detecting means, the opening and closing valve is changed to a second position in which the pressure oil supply means is inhibited from supplying pressure oil.

Abstract: A coaxial hydraulic actuator system utilizes a vane pump close coupled to a vane actuator. The vane pump includes a rotatable housing which is perpendicularly movable by a control piston to direct fluid flow through first and second fluid conduits in a pintle port transfer shaft. The transfer shaft conduits are in communication with first and second variable volume compartments in the vane actuator. Thus, controlled movement of the vane pump housing results in corresponding resulting angular movement between the actuator vane and the actuator housing. This relative angular positioning can be used to control the relative positioning between first and second loads, such as the rotors of a dual permanent magnet generator.

Abstract: The problem of sealing a communication bore (56) in a port plate (40) is solved with a self-sealing transfer tube assembly (52). The transfer tube assembly (52) includes a coupling element (64) which is received in a supply bore (60) which intersects the communication bore (56). A relatively small window (78) is provided in the coupling element to provide hydraulic communication between the transfer tube assembly (52) and the port plate porting area (48), while its solid side wall (68) otherwise seals the outer portion of the communication bore (56).

Abstract: An improved hydraulic apparatus is disclosed having a hydraulic device (14) receiving conditioned hydraulic fluid directly from an inlet port (62) in a case (12) full of hydraulic fluid (16) with the conditioned hydraulic fluid having a characteristic which is better than the characteristic of the fluid within the case. The characteristic may be that the hydraulic fluid is cooled to a temperature below the temperature of the hydraulic fluid within the case, is filtered, or is deaerated. Cooled hydraulic fluid is supplied from a heat exchanger (58) in fluid communication between an outlet port of the case and the inlet port of the case to supply the hydraulic fluid contained within the case. The hydraulic fluid is filtered by a filter (54) external to the case. A deaerator (65) may be located in a fluid circuit external to the case between a scavenge pump (50) and the inlet port (67). Hydraulic fluid is pumped by a charge pump (26) to the input port (72) of the hydraulic device.

Abstract: A hydraulically operated continuously variable transmission comprises a hydraulic pump and a hydraulic motor having a motor cylinder including an integral tubular member. A distribution disc is coupled to the motor cylinder at one end of the tubular portion and has oil passages communicating with the hydraulic pump and the hydraulic motor. A hollow fixed shaft is inserted in the tubular member, and a distribution ring is axially movably mounted on the fixed shaft and has an end face slidably held against the distribution disc. A mechanical seal assembly includes an annular rotatable seal member rotatably disposed in the tubular member, and an annular fixed seal member axially movably, but nonrotatably, mounted on the fixed shaft.

Abstract: A hydraulic system for operating the rollers and one or more steam chests in a laundry flatwork ironer. A two-way, variable delivery, high pressure, main pump operates a hydraulic motor driving the ironer rollers. A one-way, fixed delivery, charge pump keeps the hydraulic circuit between the main pump and the hydraulic motor fully charged. The charge pump also powers a hydraulic control circuit for the main pump and controls the operation of steam chest lift cylinders. The control circuit for the main pump has a positioning cylinder and a speed control cylinder which jointly control the direction and delivery rate of the main pump, thereby controlling the direction and speed of the ironer rollers. The control circuit has a solenoid valve for stopping the hydraulic motor in an emergency and a solenoid valve for selectively controlling the speed of the chest lift cylinders.

Abstract: A hydraulic continuously variable speed transmission includes a hydraulic pump and a hydraulic motor, at least one of said hydraulic pump and motor being of variable displacement type. A hydraulic path is formed in a member of the pump which rotates in synchronism with an output shaft of engine, for communicating hydraulic a pressure chamber of the hydraulic pump with a drain. A check valve is provided in the hydraulic path for closing the hydraulic path under centrifugal force created by the rotation of the member when this member is in rotation faster than a predetermined speed, and for opening the hydraulic path against a centrifugal force when the member is in rotation slower than the predetermined speed.

Abstract: The vibrating roll apparatus has a hydrostatic roll body drive drive. An internal-combustion engine drives a pump unit which includes an inclined disk pump of variable displacement and a filling pump. At least one hydraulic drive motor which is fed a pressurized medium by the inclined disk pump powers the hydrostatic roll body drive. An eccentric body in the roll body of the vibrating roll is driven by a mechanical power transmission device with a built-in clutch also powered by the internal-combustion engine. According to the invention the clutch is flanged to the pump unit and provided with a hydrostatically-operated clutch mechanism, which is connectable with the pressurized side of the filling pump by a clutch valve for engagement of the clutch. In this way a space-saving compact form for the drive for the eccentric body including means for its control with optimum conditions for clutch operation is attained.

Abstract: A hydraulically operated continuously variable transmission includes a hydraulic motor coupled to an output shaft and having a motor swash plate and a motor cylinder supporting an annular array of slidable motor plungers held in slidable contact with the motor swash plate, a distribution member integral with the motor cylinder, a hydraulic pump coupled to an input shaft in sliding contact with the distribution member and having a pump swash plate movable with the motor cylinder and a pump cylinder supporting an annular array of slidable pump plungers held in slidable contact with the pump swash plate, a closed hydraulic circuit interconnecting the hydraulic pump and the hydraulic motor, the pump cylinder being coaxially surrounded by the motor cylinder with a hydraulically hermetic chamber defined therebetween, and a replenishing pump operatively coupled to the input shaft and connected to the closed hydraulic circuit through a replenishing oil passage.

Abstract: A hydraulic motor and a hydraulic pump are interconnected by a closed hydraulic circuit. A lubricating chamber is defined around the sliding surfaces of the swash plate and the plungers of at least one of the hydraulic pump and the hydraulic motor. A shuttle valve has two input ports connected to respective oil passages, the shuttle valve being shiftable to connect the one of the oil passages which is of lower oil pressure to the output port of the shuttle valve when the differential pressure between the oil passages is relatively large. A first relief valve is opened to communicate the output port to the lubricating chamber when the oil pressure in the output port exceeds a first pressure level. A second relief valve connected between the first relief valve and the lubricating chamber is opened when the oil pressure between the first relief valve and the lubricating chamber exceeds a second pressure level lower than the first pressure level.

Abstract: In a hydrostatic continuously variable transmission, a pump cylinder of a swashplate type hydraulic pump is integrally and coaxially coupled with a motor cylinder of a swashplate type hydraulic motor. A number of distributor valves are radially arranged for reciprocal movement between radially inner and outer positions to put a large number of pump ports in the hydraulic pump into communication with the higher and lower pressure oil passages, and an eccentric ring circumscribed about the distributor valves is connected to an input member of the hydraulic pump for movement between a clutch OFF position and a clutch ON position. A clutch spring is connected to the eccentric ring for biasing the eccentric ring toward the clutch OFF position, and a weight is added to the eccentric ring and adapted to exhibit a centrifugal force for moving the eccentric ring toward the clutch ON position against a spring force of the clutch spring.

Abstract: An improved closed-loop hydrostatic transmission system is provided of the type including a pump (11), a motor (13), and a pair of conduits (15 and 17). The system includes a main control valve (43) and a charge pump (23) which is the sole source of make-up fluid to the closed-loop system and the sole source of control fluid for varying the pump. The system includes a power limiting means comprising first and second pressure relief valve means (75 and 77) operable to provide fluid communication from whichever side of the closed-loop is at high pressure to the system reservoir whenever system pressure exceeds the predetermined maximum pressure. The motor is adapted to transmit drive torque to a reversible load (37) of the type having a known inertia and a predeterminable time of deceleration from maximum speed operation in one direction to a standstill condition.

Abstract: A hydraulic continuously variable speed transmission comprises a hydraulic closed circuit for hydraulically connecting the hydraulic pump and the hydraulic motor, a direct clutch valve placed in the closed circuit to block it, a speed reduction ratio control actuator to control the speed reduction ratio, a direct clutch actuator for moving said direct clutch valve from a full-open position to a full-closed position, ratio detecting means which detects the speed reduction ratio and valve position detecting means which detects position of the direct clutch valve to find if the direct clutch valve is moved to a slight-open position. The direct clutch valve is moved quickly from the full-open position to the slight-open position when it is found by the ratio detecting means that the speed reduction ratio has become "1", and then the direct clutch valve is moved slowly from the slight-open position to the full-closed position when it is found that the direct clutch valve has been moved to the slight-open position.