Abstract: A working machine includes a prime mover, a traveling pump configured to deliver hydraulic fluid at a flow rate corresponding to an angle of the swashplate, a traveling motor configured to be rotated by the hydraulic fluid delivered from the traveling pump so as to have a rotation speed shiftable between a first speed and a second speed higher than the first speed, a traveling change-over valve shiftable between a first state to set the rotation speed of the traveling motor to the first speed and a second state to set the rotation speed of the traveling motor to the second speed, an operation device, an operation valve configured to change the angle of the swashplate of the traveling pump according to operation of the operation device, an actuation valve provided upstream or downstream of the operation valve and fluidly connected to the operation valve, and a controller configured or programmed to output a control signal to control the actuation valve in such a way that, when the traveling change-over valve i

Abstract: A washing machine appliance includes a wash basket rotatably mounted within a wash tub for receiving of a load of articles for washing and a drive motor having a motor shaft for selectively rotating the wash basket and an agitation element. A cooling fan is mechanically coupled to the motor shaft for urging a flow of air as the drive motor rotates the motor shaft and a fan cover is positioned over the cooling fan. The fan cover includes an endcap positioned opposite the cooling fan relative to the drive motor along an axial direction, a peripheral portion defining a plurality of ventilation openings spaced apart along a circumferential direction, and a plurality of louvers positioned over the plurality of ventilation openings for directing the flow of air away from the drive motor.

Abstract: A working machine includes a prime mover, a hydraulic pump to be driven by power of the prime mover to output operation fluid, a hydraulic actuator to be actuated by the operation fluid outputted from the hydraulic pump, a first setting member to accept selection of a set revolving speed of the prime mover, a second setting member to accept selection of a set speed of the hydraulic actuator, a revolving speed controller portion to control operation of the prime mover based on the set revolving speed, and a speed controller portion to control operation of the hydraulic actuator based on the set speed. The speed controller portion being configured to change an operation speed of the hydraulic actuator in accordance with the set revolving speed accepted by the first setting member, the operation speed of the hydraulic actuator corresponding to the set speed accepted by the second setting member.

Abstract: A construction machine includes a bidirectionally tiltable type hydraulic pump 2, a hydraulic cylinder 1 having a cap chamber 1e and a rod chamber 1f, a first flow path 11 connecting the hydraulic pump 2 and the cap chamber 1e, a second flow path 12 connecting the hydraulic pump 2 and the rod chamber 1f, a discharge flow path 16 branched from the first flow path 11, a discharge valve 32 that is disposed in the discharge flow path 16 and controls a discharge rate of hydraulic working oil from the cap chamber 1e to the discharge flow path 16, an operation device 54 that instructs an action of the hydraulic cylinder 1, and a controller 56.

Abstract: Disclosed is a system for controlling a hydraulic pump in a construction machine which can reduce the discharge flow of the hydraulic pump in proportion to the load pressure of the hydraulic pump to enhance operability by the driver. The present invention provides the system for controlling the hydraulic pump in the construction machine, which is characterized by detecting the discharge pressure of the hydraulic pump and the operation activity of an operation lever, and comparing the detected discharge pressure of the hydraulic pump and a predetermined pressure value, and when the detected discharge pressure exceeds the predetermined pressure value, the maximum dischargeable flow of the hydraulic pump is reduced in proportion to the difference between the detected pressure and the predetermined pressure value.

Abstract: A power machine having an engine that generates a torque output and a power conversion system configured to receive the torque output and provide a drive power signal in response to actuation signals for propelling the machine is disclosed. An engine controller provides an engine torque data signal indicative of a torque load on the engine. A user input device generates an input signal indicative of intention to propel the machine. An electronic controller is in communication with the user input device, the power conversion system, and the engine controller. The electronics controller receives the input signal and provides actuation signals to the power conversion system. The electronic controller further provides the actuation signals as a function of the engine torque data signal to limit the engine torque load.

Abstract: A power split transmission includes a hydraulic power branch having two hydraulic machines arranged in a hydraulic circuit, at least one of which comprises an adjustable displacement. The transmission comprises a control device for controlling the transmission ratio, and is configured to actuate at least the one adjusting device at a displacement setting. The displacement setting is adjusted in relation to a displacement setting oriented to a current demand, at least in a drive mode or drive mode section in which the displacement of one of the hydraulic machines reaches a maximum or is reduced from this maximum.

Abstract: A vehicle includes an internal combustion engine, a first hydraulic pump/motor coupled with the internal combustion engine, and a second hydraulic pump/motor is coupled with at least one driven wheel of the vehicle. A clutch establishes a driving connection between the first hydraulic pump/motor and the internal combustion engine, and selectively interrupts the driving connection when disengaged. At least one vehicle accessory device is coupled to the first hydraulic pump/motor. The at least one vehicle accessory device is operable under power of the internal combustion engine when the clutch is engaged and the internal combustion engine is running, and the at least one vehicle accessory device is operable directly by the first hydraulic pump/motor operating in a motor mode when the clutch is disengaged, regardless of whether or not the internal combustion engine is running. A corresponding method of operating the vehicle is also provided.

Abstract: A first target engine speed is set in response to a command value commanded by a command unit and a second target engine speed lower than the first target engine speed is set based on the first target engine speed. A reduction range from the first target engine speed to the second target engine speed is set according to a type of a hydraulic actuator operated by an operation lever or a combination of plural hydraulic actuators operated by an operation lever.

Abstract: In a hydraulic power cylinder equipped power steering apparatus, a part of each of first and second hydraulic lines, associated with respective hydraulic chambers of the power cylinder, is constructed by a low-rigidity line functioning as a variable volume hydraulic-line section and formed of an elastically-deformable, flexible tube, made of a synthetic rubber. The line length of the low-rigidity line, which is disposed in each of the first and second hydraulic lines, is dimensioned so that each of an apparent modulus Ke of volume elasticity of working fluid in a first hydraulic pressure transmission path and an apparent modulus Ke of volume elasticity of working fluid in a second hydraulic pressure transmission path is set within a specified apparent volume modulus range, defined by an inequality 100 MPa?Ke?300 MPa.

Abstract: A method for derating a power source to limit damage to a drive train of a machine including determining a first operational parameter associated with a power conversion unit and a second operational parameter associated with the power source, selecting, based on the first operational parameter associated with the power conversion unit and the second operational parameter associated with the power source, a power source derate value, and reducing an available power output associated with the power source according to the derate value.

Abstract: A protection system is provided for a work machine with a power source. At least one sensor is configured to monitor a fluid parameter of a work machine system external to the power source. The sensor is further configured to produce a signal indicative of a value of the fluid parameter. The component protection system has a control module in communication with the at least one sensor, the control module being configured to derate a power source output base upon the value of the fluid parameter.

Abstract: A forward/backward switching control apparatus for a hydraulic drive vehicle that includes the following structures. A variable displacement type hydraulic pump driven by an engine for discharging pressure oil in both directions. An electromagnetic pump inclination angle control mechanism making the discharge displacement of the variable displacement type hydraulic pump variable and for causing the same to discharge in both directions. An electric control outputting signals to run the hydraulic drive vehicle forward, backward and forward/backward. A control device outputting, when the electric control is switched forward/backward to output the forward/backward signal and when the time for switching the forward/backward signal is not longer than a preset time, a first modulate signal for delaying the return times from the forward position to the neutral position and from the backward position to the neutral position to the electromagnetic pump inclination angle control mechanism.

Abstract: A hydraulic system for a motor vehicle having a convertible top (2) which can be folded back has a convertible-top control system (1) and further hydraulic control devices (3, 4) which can be activated by a common hydraulic pump (6). In hydraulic lines (8, 9) leading to the convertible-top control system (1) there are arranged hydraulic valves (13, 14) which enable optional operation of the convertible-top control system (1) or of the further control devices (3, 4). Because of this, the hydraulic system turns out to be particularly simple structurally.

Abstract: The invention related to a drive system with at least two hydraulic actuators, which are supplied with a hydraulic fluid by means of at least one pump. The drive system comprises at least one further second pump (15′) arranged parallel to the first pump (15), wherein the pumps are bi-directionally speed-regulated, and a valve arrangement (59) with one inlet per pump (61.1, 61.2), wherein each one of the inlets is connected to a pump (15), and with a number of outlets (63.1, 63.1′, . . . 63.4, 63.4′) which are connected to the actuators (1.1 . . . 1.4), wherein the inlets (61) can be connected to the outlets (63) in a pre-determined manner.

Abstract: A hydrostatic drive system is provided for a vehicle, in particular an industrial truck, with a hydrostatic traction drive system (16), a hydraulic work system (13) and a hydraulic steering system (9). The invention provides a drive system that is compact and exhibits improved operating behavior during the change from traction operation to coasting operation.

Abstract: A direction control valve is formed by providing a main spool for establishing and blocking communication between an inlet port, first and second actuator ports and first and second tank ports. A pressure compensation valve comprising a check valve portion and pressure reduction portions is provided for compensating the pressurized fluid with a load pressure and supplying it to the inlet port. A plurality of valve blocks are connected with communicating respective first and second tank ports and respective pump ports, and either one of pump port is connected to a main port. In either case, the pump port is connected to the main input port to any one of the first and second tank ports is connected to the main tank port.

Abstract: A closed center-load sensing system, capable of varying a pump discharge volume easily and with a high degree of accuracy, includes a power source having an indicator for indicating a rotational speed, a variable volume hydraulic pump driven by the power source, actuators driven by pressure oil discharged from the variable volume hydraulic pump, change-over valves for controlling the flow of the pressure oil, an indicator for setting the rotational speed of the power source in a load sensing system in which the pressure difference between the pump pressure and the actuator load pressure is maintained at a predetermined pressure and the rate of flow of a discharge from the variable capacity hydraulic pump is varied when the pressure difference between a pump pressure and an actuator load pressure varies, a controller for computing and outputting a command signal for the rotational speed of the power source in response to a command signal from the indicator, and an electronic proportional control governor for c

Abstract: A controller for a hydraulic fluid flow control apparatus determines a quantity necessary for loading/unloading operations according to a signal from a lever operating degree detector, and controls a variable displacement type hydraulic pump to obtain the quantity. Accordingly, unnecessary hydraulic fluid flow in the hydraulic apparatus is reduced. The controller determines when a vehicle is stopped according to a signal from a clutch ON-OFF detector or a neutral sensor, and can raise the rpm of an engine. Therefore, when the loading/unloading operations are being executed while the vehicle is stopped, there is no need to operate the accelerator pedal.

Abstract: Control system for a load-sensing hydraulic drive circuit comprising; at least one hydraulic pump; hydraulic actuators driven by the hydraulic pump; and a pressure compensated flow control valve between the pump and each of the actuators, for controlling a flow rate of fluid to each actuator in response to a control signal. The control system has first detection means for detecting a differential pressure between the pump delivery pressure and the maximum load pressure; second detection means for detecting the pump delivery pressure; first means for calculating a differential pressure target pump delivery amount Q.DELTA.p to hold the differential pressure constant; second means for calculating an input limiting target pump delivery amount QT based on at least a pressure signal from the second detection means and an input limiting pump function; third means for selecting one of the differential pressure target delivery amount Q.DELTA.

Abstract: Speed regulation of pump drive is set by a pressure-regulating valve providing a constant control pressure for a plurality of normal loads. If a high fluid consumption load such as the lifting cylinder of a forklift truck is to be simultaneously actuated the pump speed and net volumetric displacement must be increased. A higher speed-regulating control pressure from the pressure-regulating valve is required. The control valve for the high consumption load has a spool with an extending inclined cam contacting the biasing spring of the pressure-regulating valve. Upon actuation of this control valve the preload of the biasing spring is increased thereby adjusting the speed-regulating control pressure output of the pressure regulating valve. The pump engine or drive speed and the net volumetric displacement are increased.

Abstract: According to the parent patent on inadequate power of the delivery pump the flow rate set at the directional control valves for the consumers is reduced in equal proportions in that electrical signals proportional to the flow rates are supplied to a summation stage and the sum voltage is compared in a comparison stage with a limit value corresponding to the maximum pump delivery flow. When the limit value is exceeded a control signal is generated with which the stroke of all the driven directional control valves can be jointly reduced. According to the application of addition the signal voltage supplied to the summation stages and corresponding to the respective flow rate can be obtained in a displacement pickup associated with each directional control valve or in a pressure pickup measuring the pilot pressure if the directional control valves are not controlled electrically but hydraulically.

Abstract: A hydraulic control system for simultaneously driving two hydraulic loads of a production machine by means of a variable delivery pump feeding drive fluid to the two loads through separate load lines, in accordance with independently controllable programs of flow rate and pressure, the two load lines being controlled by two proportional P/Q valves, the pump being continuously adjusted for a constant pressure gradient in the load line which carries the higher pressure, the other load line having a pressure imbalance compensating device in the form of either a flow rate measuring device, a pressure balancing valve, or a displacement-to-voltage converter connected to the associated load.

Abstract: An earth-moving machine has an automatic device for minimizing the running speed of the main engine when no power is required by the hydraulic actuators. This device establishes a predetermined hydraulic fluid flow-rate in the servocontrol in the non-neutral position of the servocontrol itself. This flow-rate is indicated by an on-off flow-rate sensor inserted in the auxiliary hydraulic control circuit between the pump and the servocontrols, this sensor controlling the variation in the operating condition of the injection pump of the main engine by means of an electromagnet.

Abstract: A control for a power drive assembly having a primary energy source, a hydrostatic pump driven by the energy source and a consumer of energy has a multiway valve between the pump and consumer and a control pressure dependent valve receiving fluid from the pump controlling its position and connections between a source of pressure fluid and a spring biased operating cylinder connected to a control lever on the primary energy source controlling operation thereof.

Abstract: The hydraulic device is provided, by way of example, with a pump (10) being driven by a Diesel motor (13) feeding pressure medium through wayvalves (18 to 20) to consumers. The speed regulator (14) of the injection pump of the Diesel motor is influenced with the assistance of a pressure admitted set cylinder (15) on which the pressure generated in a control line (16) acts for the purpose of increasing the speed of the internal combustion engine. This pressure is controlled in cooperation of one of the wayvalves (18) for a single acting consumer and a pressure control valve (28) in such a manner that when actuating a customary wayvalve a constant pressure is generated in line (16). When actuating the other wayvalve (18) a specific control edge (48) becomes active generating an increasing pressure in line (16) being proportional for the deflection of the control slide.

Abstract: A control system is provided for a hydraulic actuating system having a multi-phase stepping motor with a driver therefor which supplies and controls DC current through each of the motor windings such that no current is induced into the control winding from adjacent windings. The stepping motor precisely controls the rotation of an eccentric cam engaging an actuating plunger which actuates a control valve of the hydraulic actuating system. The driver receives control signals from a computer programmed to calculate, from user input command signals indicative of the desired system condition, and generate those control signals which most quickly achieve a rough approximation of the desired system condition. After this rough approximation is attained, the computer generates new control signals for the driver as a function of feedback signals and/or system component characteristics so as to precisely achieve the desired system condition.

Abstract: A transport refrigeration system is connected to a hydraulic system including a pump, control valves, a reservoir and a hydraulic piston. When the refrigeration system is running, the hydraulic system is in a bypassing or idling mode and the diesel and compressor are run responsive to cargo refrigeration requirements. When the hydraulic system is activated, the diesel is caused to operate at a preselected speed for maximum hydraulic flow and the refrigeration electrical system unloads the compressor to divert more engine power to the hydraulic pump.

Abstract: A hydraulic system is disclosed for energizing the power steering and various work handling hydraulic load circuits of a lift truck. A single positive displacement pump supplies the requirements of the plural load circuits and is driven by a changeable speed prime mover. Manually actuable selector means are operatively connected with the load circuits and speed control means are provided for the prime mover. A priority demand valve is connected between the pump and the respective load circuits. When only the power steering circuit is selected, the prime mover is operated in a low speed range and the priority demand valve supplies the required flow to the power steering circuit. When the lift circuit is selected, the prime mover is operated in a high speed range and the priority demand valve supplies the flow requirements to the power steering circuit and to the lift circuit.

Abstract: A load responsive fluid power and control system in which the speed of the prime mover, driving a fixed displacement pump, is varied to maintain a constant pressure differential between pump discharge pressure and maximum system load pressure, above a certain predetermined system flow level and in which this constant pressure differential is maintained by pump flow bypass control, at system flows below this predetermined level.

Abstract: An axle shaft and pump drive mechanism (12) for a vehicle (10) includes a continuously variable transmission unit (24), an axle shaft (20), a pump (22), and a coupling device (34,78) for connecting the transmission unit (24) to the axle shaft (20) or to the pump (22) and operating them individually through an infinitely variable speed ratio range. When the vehicle, such as a backhoe loader, is not being propelled, the continuously variable transmission unit (24) can be used to drive the implement pump (22) which can then be of the fixed displacement type for improved effectiveness.

Abstract: A lift truck is disclosed with a changeable speed electric motor for driving a single positive displacement pump to supply the power steering and various work handling hydraulic load circuits. Manually actuable selector means are operatively connected with the load circuits and a speed range control means is operatively connected with the selector means for energizing the electric motor in different speed ranges according to the actuation of the selector means. A priority demand valve is connected between the pump and the respective load circuits and supplies fluid to the load circuits, giving priority to the power steering circuit. The speed range control means includes speed regulating means for the electric motor. The motor is energized from the battery and the regulating means includes a pulsing circuit with a motor current feedback to vary the mark/space ratio of the pulses produced by the pulsing circuit.

Abstract: A lift truck hydraulic control system designed to conserve energy includes a pair of separately controlled pumps (21, 22). One pump (21) supplies pressure fluid to a valve (12) for a steering cylinder (11) by way of a high priority port (34) of a priority valve (32) with the low priority flow passing to parallel connected lift and tilt valves (19, 18) which control operation of the lift cylinder (15) and tilt cylinders (16, 17), respectively. The capacity of pump (21) is sufficient to provide proper, effective operation of the steering and tilt functions but is not adequate to provide hydraulic fluid flow for high speed expansion of the lift cylinder (15). The other pump (22) is operated to supply additional pressure fluid flow for high speed lift only when the lift valve (19) is shifted to a raise position. In one embodiment, a low speed lift is obtained by using the output of the pump (21) and a high speed lift is obtained by selectively adding the output of the second pump 22.

Abstract: An apparatus and method of controlling the input power to a drill feed or other hydraulic system in which the hydraulic power source is obtained from a compressed air supply. Wherein, the flow of air is varied in response to a hydraulic signal controlled by the load demand of the hydraulic system. Low and high mode controls are provided to operate hydraulically actuated mechanisms; and a hydraulic absorbing load is imposed to prevent stall or overspeed of the pump and motor during low load conditions.

Abstract: An improved pressure sensitive valving arrangement is provided for a power steering unit for a lift truck, and in particular for a battery powered lift truck. To the conventional implement valve is added an accumulator charging means which includes an additional valve, herein called a "blocking or control valve", which additional valve is downstream from the implement valve and which additional valve, when actuated, blocks the flow of fluid through the implement valve to thereby build up pressure for charging an accumulator. The blocking valve includes a blocking spool which operates against a pressure-actuated pilot plunger such that when the pressure in the accumulator reaches or exceeds a predetermined amount, the pilot plunger shifts the blocking spool to permit the fluid to again flow through the implement valve.

Abstract: The throttle of an engine is controlled to maintain its speed substantially constant in spite of variations of load upon it. The illustrated load comprises hydraulically operated equipment in a hydraulic system powered by a pump driven by the engine. Throttle control mechanism comprises a pair of cylinders supplied from fluid pressure in the hydraulic system. Pistons in the respective cylinders are connected by pivots with a control arm linked to the throttle control. When equipment is hydraulically operated from the hydraulic system, the fluid back pressure against the pump increases, this back pressure being greater the greater the hydraulic load. The increased load on the engine from the pump would slow the engine down if its throttle opening were to remain at its original setting.

Abstract: A hydraulic power system having a plurality of variable displacement pumps for supplying pressurized fluid for manipulation of one or more implements includes control means operative to automatically adjust pump displacement to the output horsepower of a prime mover driving the pumps of a system. The control means includes an underspeed valve responsive to a deviation in the speed of the prime mover from any one of a wide range of selected speeds to transmit a fluid pressure signal to servo control means for adjusting the displacement of the pumps in proportion to engine output. The control means includes an infinitely variable orifice adjustable with throttle movement for adjusting the underspeed valve to respond to a deviation from a wide range of selected engine speeds.

Abstract: A hydraulic power system having a plurality of variable displacement pumps for supplying pressurized fluid for manipulation of one or more implements includes control means operative to automatically adjust pump displacement to the output horsepower of a prime mover driving the pumps of the system. The control system includes an underspeed valve responsive to a deviation in the speed of the prime mover from any of a wide range of selected speeds to transmit a fluid pressure signal to servocontrol means for adjusting the displacement of the pumps. The underspeed control means includes an infinitely variable orifice connected by way of lost motion linkage to the engine throttle control for adjusting the underspeed valves to respond to a deviation of an infinite range of engine speeds.

Abstract: An energy conserving hydraulic system for a lift truck or the like including a hydraulic tilt cylinder and a hydraulic lift cylinder subject to varying load requirements, manually operable valves for controlling the cylinders, a first, high volume hydraulic pump, a second, low volume hydraulic pump, a reversible, bidirectional DC motor for simultaneously driving both the pumps, and a piping system connecting the pumps to the valves such that for one direction of drive of the motor, the first pump will deliver a high volume of hydraulic fluid to the valve for operation of the lift cylinder, and for the other direction of drive of the motor, the first pump will be unloaded. A conduit is also arranged such that for the other direction of drive, the second pump will deliver a low volume of hydraulic fluid to the valve for directing the same to the tilt cylinder. An electrical direction control for controlling the direction of drive is responsive to the valves.

Abstract: An overspeed protection control for an engine which drives at least one pump and having valve means selectively operable to cause an increase in pressure in a circuit supplied by said pump and a resulting increase in load torque on the engine. Means responsive to the engine speed exceeding a predetermined value causes operation of the valve means, and includes a control valve positionable either in response to a pressure differential across an orifice in the circuit supplied by the pump with the pressure differential being an indication of flow rate and, therefore, engine speed, or operable by a control circuit including means for detecting engine speed.

Abstract: A power steering system for electric vehicles in which an electric drive motor for the supply pump of a power steering system is controlled by a motor control which is in turn controlled by the steering demand of the operator. The motor and pump are operated only during steering operations and only at the power level required for any steering demand.

Abstract: The throttle of an engine is controlled to maintain its speed substantially constant in spite of variations of load upon it. The illustrated load comprises hydraulically operated equipment in a hydraulic system powered by a pump driven by the engine. Throttle control mechanism comprises a pair of cylinders supplied from fluid pressure in the hydraulic system. Pistons in the respective cylinders are connected by pivots with a control arm linked to the throttle control. When equipment is hydraulically operated from the hydraulic system, the fluid back pressure against the pump increases, this back pressure being greater the greater the hydraulic load. The increased load on the engine from the pump would slow the engine down if its throttle opening were to remain at its original setting.