Condition Responsive Control Of Motive Fluid Flow Patents (Class 60/459)
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Patent number: 5365829Abstract: An apparatus for operating feed bars to move a workpiece between stages of a pressing machine includes cylinder devices. Each of the cylinder devices serves to move the feed bars linearly and each has a respective absolute encoder. The cylinder devices include a feed cylinder device which is responsive to hydraulic pressure to linearly advance and return the feed bars. First and second clamp cylinder devices are responsive to hydraulic pressure to move the feed bars linearly so as to clamp and unclamp the workpiece between the feed bars A hydraulic pressure supply circuit is connected commonly to each of the cylinder devices. Hydraulic pressure is applied to the cylinder devices through respective servo valves of a hydraulic valve arrangement.Type: GrantFiled: December 31, 1992Date of Patent: November 22, 1994Assignee: Aida Engineering, Ltd.Inventors: Shozo Imanishi, Toshihiko Arai
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Patent number: 5363649Abstract: A hydraulic pressure system includes a pump and a dry valve situated in the inlet of the pump, the dry valve being actuated by a pilot valve capable of capturing the pressure differentials between inlet and outlet of the pump for shifting the dry valve between opened and closed positions. In the dry operational mode, the pump inlet operates at a pressure below atmospheric, thus providing a pressure differential substantial enough to move the dry valve to an opened position. In the preferred form, the pilot valve is a solenoid actuated two-position, four-way, spring loaded valve. The dry valve is a gate valve directly coupled to a fluid control motor.Type: GrantFiled: December 18, 1989Date of Patent: November 15, 1994Assignee: Dana CorporationInventors: James R. McBurnett, Weston R. Poyner
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Patent number: 5343703Abstract: A control apparatus comprises a plurality of servomechanisms for controlling a control surface of an aircraft. Each of the servomechanisms is equipped with a control valve for controlling the oil pressure in hydraulic chambers of the actuator assembly operatively connected to the control surface, and a switching valve provided between the actuator assembly and the control valve and shiftable to assume driving, bypassing and damper valve positions. The switching valves of the servomechanisms are shifted to assume the driving valve position in a normal operation. If one of the servomechanisms is damaged, the switching valve of the damaged servomechanism is shifted to assume the bypassing valve position. If all of the servomechanisms are damaged, the switching valves of the damaged all servomechanisms are shifted to assume the damper valve position.Type: GrantFiled: November 4, 1993Date of Patent: September 6, 1994Assignee: Teijin Seiko Co., Ltd.Inventor: Toshio Kamimura
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Patent number: 5333450Abstract: An apparatus for adjusting the pressure of working fluid provided to the load or user via a hydraulically actuatable control valve is provided. The apparatus includes a comparator that compares a given or desired control pressure for the control valve with the predominant present load pressure. The resulting pressure differential is used to re-adjust the control valve or to re-adjust a pressure compensator positioned upstream of the control valve with respect to the direction of the flow of working fluid flowing to the user.Type: GrantFiled: December 7, 1992Date of Patent: August 2, 1994Assignee: Mannesmann Rexroth GmbHInventors: Herbert Blendinger, Gunter Fertig, Armin Stellwagen
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Patent number: 5333454Abstract: A connector 5 having an outlet 4 for delivering a pressure oil to a power steering apparatus PS is secured in an opening of a valve receiving bore 2 in which a flow controlling spool valve 3 is received. The connector 5 includes an axial bore 5a which continues from the outlet 4 and in which a valve sleeve 10 is slidably fitted. The valve sleeve 10 has pressure oil passages 11, 12 therein in which orifices 13, 14, 15 are formed, and pressure differentials thereacross are utilized to operate the spool valve 3 in order to return an excess amount of flow. At its outer end, the valve sleeve 10 is formed with a flange 10b, and a restriction 20 is defined between the outer peripheral surface of the flange 10b and the internal peripheral surface of the valve receiving bore 2 for restricting the flow rate of the pressure oil. A pressure differential developed across the restriction 20 is effective to move the valve sleeve 10 to control the orifices 14, 15 so that the latter may be reduced.Type: GrantFiled: February 16, 1993Date of Patent: August 2, 1994Assignee: Jidosha Kiki Co., Ltd.Inventor: Masaya Nikaido
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Patent number: 5317870Abstract: A pressure source for a pressure device has a pump for pumping fluid from a tank, an accumulator connected to the pump and to a pressure device, a device for detecting the pressure in the accumulator, and a control system for controlling the operation of the pump in an ON/OFF manner based on results of detection of the pressure detecting device. The pressure detecting device includes a pressure switch to detect pressure in the accumulator to produce an ON/OFF signal, and a pressure sensor outputting a pressure signal corresponding to pressure in the accumulator. The control system judges whether the pressure sensor is normal or out of order, and when the pressure is normal, controls the operation of the pump with the pressure signal. The pressure signal and the ON/OFF signal are compared with each other, and when these signals do not correspond, the pressure switch is determined to be out of order, and when the pressure sensor is out of order, the pump operation is controlled with the ON/OFF signal.Type: GrantFiled: May 20, 1992Date of Patent: June 7, 1994Assignee: Honda Giken Kogyo Kabushiki KaishaInventor: Shinichi Inagawa
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Patent number: 5271227Abstract: In the hydraulic apparatus (1) according to a first aspect of the present invention, mid-pressures between the inlet side and outlet side pressures of a first and a second pressure compensating valves (4, 4') are permitted to act on the flow rate decreasing side pressure receiving surfaces (4b, 4b') thereof through first and second mid-pressure supplying means (13, 13'), thereby restraining operational error and malfunction of the pressure compensating valves (4, 4'). In the hydraulic apparatus (20) according to a second aspect of the present invention. when actuating valves are made to assume neutral position, holding pressures of hydraulic actuators (5, 5') are permitted to act on flow rate decreasing side pressure receiving surfaces (4b, 4b') of pressure compensating valves (4), (4') so that spools of the pressure compensating valves are held at compensating position, thereby improving the response of the hydraulic actuators (5, 5') to lever actuation.Type: GrantFiled: January 9, 1992Date of Patent: December 21, 1993Assignee: Kabushiki Kaisha Komatsu SeisakushoInventors: Teruo Akiyama, Kiyoshi Shirai, Naoki Ishizaki, Koji Yamashita, Shinichi Shinozaki
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Patent number: 5267440Abstract: In a controller (229) of a hydraulic control system for construction machines, a valve control signal calculating function (301) works such that when an operation pattern signal (A-I) for actuators (201, 202 . . . ) is outputted, it selects corresponding one of plural output patterns for an auxiliary valve control pressure stored, as a function of a differential pressure signal between a pump delivery pressure and a maximum load pressure, in relation to the operation pattern signals, followed by calculating an auxiliary valve control pressure (Pc) dependent upon the differential pressure signal based on the selected output pattern, and also selects corresponding one of plural sets of rates of change (K . . . , K . . . ) for the auxiliary valve control pressure stored in relation to the operation pattern signals, followed by combining the calculated auxiliary valve control amount with the selected set of speed changes to calculate each of valve control signals (S21-S26).Type: GrantFiled: May 4, 1992Date of Patent: December 7, 1993Assignee: Hitachi Construction Machinery Co., Ltd.Inventors: Kazunori Nakamura, Yusuke Kajita, Toichi Hirata, Genroku Sugiyama, Hiroshi Onoue, Hideaki Tanaka, Osamu Tomikawa, Masakazu Haga, Hiroshi Watanabe
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Patent number: 5251443Abstract: In a pressure-control device for affecting the closing behavior of powershift clutches (K.sub.1 -K.sub.X) in a powershift transmission, a regulating valve (1) cooperates with a damping device (2) as pressure-control valve. Chokes (4, 40, 400) for a more or less smooth connection are arranged in combination with pressure lines (P.sub.S, P.sub.R) over the pressure cycle when the clutch concerned (K.sub.1 -K.sub.X) is engaged. The travel of the damper piston (21) in a direction toward the regulating valve (1) is shortened by a pressurizing piston device (3) cooperating with the piston (21) of the damping device (2). Thus the time for the slipping phase in the engaged clutch concerned is shortened and, together with a higher initial pressure after the clutch is filled, the friction is limited.The limitation of the friction can also be obtained by adding a second choke in parallel in the control pressure line (Pr) by which the choked cross section is increased.Type: GrantFiled: January 30, 1992Date of Patent: October 12, 1993Assignee: Zahnradfabrik Friedrichshafen AGInventors: Friedrich Ehrlinger, Wilhelm Hardtle, Peter Hartig
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Patent number: 5218895Abstract: An apparatus, is adapted to controllably position a movable element in a hydraulic motor. A controller receives a request signal and velocity and/or position signals from sensors. The controller, in accordance with a control scheme using velocity and/or position feedback, determines the flow of hydraulic fluid to the cylinder needed to reduce velocity and/or position errors. A directional valve, actuated by an electrohydraulic pilot system, delivers hydraulic fluid to the hydraulic motor.Type: GrantFiled: June 15, 1990Date of Patent: June 15, 1993Assignee: Caterpillar Inc.Inventors: Michael S. Lukich, Eric A. Hutchison, Lisa A. Obermaier
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Patent number: 5209063Abstract: A hydraulic circuit arranged to prevent the load pressure in one of the hydraulic actuators at the time of starting from becoming abnormally high thereby preventing fluid under pressure from being relieved by the safety valve when a plurality of hydraulic actuators are operated at the same time, wherein the function of one of the pressure compensating valves is temporarily enhanced by introducing the load pressure in the hydraulic actuator so as to supply a large quantity of fluid under pressure to the hydraulic actuator connected to the pressure compensating valve so that the operating speed of the hydraulic actuator can be increased.Type: GrantFiled: May 4, 1992Date of Patent: May 11, 1993Assignee: Kabushiki Kaisha Komatsu SeisakushoInventors: Kiyoshi Shirai, Shigeru Shinohara, Teruo Akiyama, Takahide Takiguchi, Naoki Ishizaki
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Patent number: 5201177Abstract: A system for automatically controlling the actuators of a construction vehicle. The system comprises electronic controller, an automatic selecting switch for selecting automatic control for actuators, as requested, control levers for being manipulated by an operator in order to instruct the controller of desired operations of the actuators, and positional sensors for sensing respective positions of the actuators and outputtng signals corresponding to the positions of the actuators to the controller. In the system, the actuators during performing repeated operations are such automatically controlled that they are controlled during a first operation by the operator's manipulations for the control levers, thereafter, during each sequential operation, they are automatically controlled by the controller on the basis of electric control currents having been automatically calculated by virtue of a displacement ratio between the actuators during a just previous operation.Type: GrantFiled: January 31, 1992Date of Patent: April 13, 1993Assignee: Samsung Heavy Industries Co., Ltd.Inventor: Ju-kyung Kim
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Patent number: 5186000Abstract: A hydraulic drive system for construction machines includes a hydraulic pump (1), a plurality of hydraulic actuators (2, 3) driven by a hydraulic fluid supplied from the hydraulic pump, a plurality of flow control valves (4, 5) for controlling flow rates of the hydraulic fluid supplied to the actuators, respectively, and a plurality of distribution compensating valves (6, 7) for controlling differential pressures across the flow control valves, respectively, the plurality of actuators including a first actuator (2) which undergoes a relatively large load pressure and a second actuator (3) which undergoes a smaller load pressure than that of the first actuator.Type: GrantFiled: March 31, 1992Date of Patent: February 16, 1993Assignee: Hitachi Construction Machinery Co., Ltd.Inventors: Toichi Hirata, Genroku Sugiyama, Yusuke Kajita
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Patent number: 5182908Abstract: An apparatus controls a fluid system of a work vehicle. The work vehicle has an engine and at least one fluid circuit which has a pump driven by the engine. A plurality of control valves controllably pass fluid from the pump to a plurality of respective work elements. The control valves have movable valve stems. A work attachment which has a respective control valve is added to the fluid system. A plurality of operator control elements provide demand signals in response to selected settings. Each demand signal is indicative of a requested fluid flow to a respective work element or work attachment. A memory device stores select parameters of the fluid system. One of the select parameters is a predetermined priority value representing the precedence in which fluid is delivered from the pump to the control valve of the work attachment. A controller receives the predetermined priority value of the work attachment and the demand signals.Type: GrantFiled: January 13, 1992Date of Patent: February 2, 1993Assignee: Caterpillar Inc.Inventors: Lonnie J. Devier, John J. Krone, Stephen V. Lunzman, Howard A. Marsden
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Patent number: 5170692Abstract: A hydraulic control system for controlling a hydraulic actuator comprising a pump for supplying fluid to the actuator and a directional valve for controlling the flow of fluid to the actuator. The directional valve includes a poppet piston that provides a variable orifice. The position of the poppet piston is controlled by a pilot flow controlled by a pilot valve which may be controlled by a solenoid controller. The flow out of the pilot valve is connected to the outlet of the directional valve. A pressure compensator is provided between the inlet to the directional valve and the pilot valve and maintains the pilot flow to the pilot valve constant. The pressure of fluid being applied to the actuator by the directional valve is also sensed and caused to produce a force opposing the opening force applied to the pilot valve to result in a smooth and accurate control of the load.Type: GrantFiled: November 4, 1991Date of Patent: December 15, 1992Assignee: Vickers, IncorporatedInventor: Kurt R. Lonnemo
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Patent number: 5167121Abstract: A hydraulic control system for a multi-linked manipulator arm monitors the desired flow of hydraulic fluid to each of the actuators for the links of the manipulator, and when the desired flow to any one or more of the actuators exceeds the available flow to the respective actuators, the flows to all the actuators are reduced on the basis of a scaling factor based on the ratio of the available flow to the desired flow of that actuator having the maximum ratio of its desired to available flows so that the relative speed of all the actuators for manipulating the arm is maintained. In some cases some actuators may have higher priority than others and a second scaling factor in which such priorities have been applied may also have to be applied to the flows to reduce the relative speeds of all actuators.Type: GrantFiled: June 25, 1991Date of Patent: December 1, 1992Assignee: University of British ColumbiaInventors: Nariman Sepehri, Real N. Frenette, Peter D. Lawrence
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Patent number: 5159813Abstract: A slewing control device for a hydraulic slewing crane adapted to supply a discharge oil from a hydraulic pump through a slewing control valve to a slewing motor and control a rotational direction and a rotational speed of the slewing motor. The slewing control device includes a brake pressure control valve for variably controlling a discharge pressure of the slewing motor, an acceleration pressure control valve for variably controlling a suction pressure of the slewing motor, and a controller for outputting to both pressure control valves a pressure control signal to be determined according to an operational condition of the crane upon braking of a slewing body and controlling both the discharge pressure and the suction pressure of the slewing motor to control a pressure differential therebetween. Accordingly, even when a braking torque is small, the slewing body can be smoothly braked to be stopped at a target position accurately with no oscillation of a suspended load remaining.Type: GrantFiled: December 5, 1990Date of Patent: November 3, 1992Assignee: Kabushiki Kaisha Kobe Seiko ShoInventors: Hideaki Yoshimatsu, Koichi Fukushima
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Patent number: 5159812Abstract: The invention refers to a hydraulic system comprising at least a variable displacement pump and at least a consumer. Means are provided to generate electrical limit signals when at least one of the consumers, preferrably a load leading consumer indicates the need for an increased delivery rate or when the variable displacement pump indicates a hydraulic under-supply. In response to the limit signals generated by the consumer need or the pump are varied in a control circuit to adjust the control signals delivered to the servo devices of the hydraulic systems such that the pump control is optimized and that the flow rates to the consumers are decreased in the mode of under-supply. In addition very simple electrical circuits are disclosed to substantially reduce the expenditure of the system.Type: GrantFiled: December 21, 1990Date of Patent: November 3, 1992Assignee: Mannesmann Rexroth GmbHInventor: Heinrich Nikolaus
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Patent number: 5146746Abstract: A loading/unloading control apparatus for a industrial vehicle control the discharge capacity of a variable displacement type hydraulic pump in accordance with the detected result of the amount of load applied to a loading/unloading hydraulic actuator or with a manual setting by an operator, thereby to obtain the most suitable working speed of the actuator for loading/unloading operations.Type: GrantFiled: December 6, 1991Date of Patent: September 15, 1992Assignee: Kabushiki Kaisha Toyoda Jidoshokki SeisakushoInventors: Katsumi Nagai, Teruyuki Nishimyou
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Patent number: 5136926Abstract: A vibration generator including an inertial body and a housing which are relatively movable and where hydraulic fluid is directed into the inertial body through a control valve mounted in the inertial body, the fluid being directed alternately into one or another working chamber which causes oscillation of the housing and any attached load. A wave form shape of pressure or flow rate of the hydraulic fluid flow is detected and used to control the frequency at which the vibration generator oscillates so that the frequency is maintained at a resonant frequency. The device has particular application in a frequency range of 20 Hertz to 1000 Hertz.Type: GrantFiled: December 21, 1989Date of Patent: August 11, 1992Inventors: David A. Bies, Stewart Page
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Patent number: 5133186Abstract: Device for controlling the pressure in a hydraulic pressure system in which the output of a constantly running pump which feeds pressure medium to a pressure system is controlled by means of a suction throttle valve which itself is actuated as a function of the pressure in the pressure system of the vacuum in the connection between pump and suction throttle valve.An over pressure in the pump output acts to close the throttle valve, while under vacuum in the pump outlet acts to open the throttle valve, thus allowing for a two point control without additional control valves.Type: GrantFiled: October 23, 1990Date of Patent: July 28, 1992Assignee: Mercedes-Benz AGInventor: Jurgen Weissinger
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Patent number: 5117634Abstract: In an apparatus for controlling the operation of hydraulic motors having infinitely adjustable eccentricity, wherein a flow-control valve between a pump and a hydraulic motor supplied with pressure medium and a control valve for adjusting the eccentricity of the hydraulic motor as a function of the operating pressure required by the hydraulic motor are provided, in connection with pressure optimization for keeping constant the torque of the hydraulic motor, the hydraulic motor is provided with a regulating device (7,10) which is mechanically connected to the eccentric (3) and transmits an eccentric adjustment outward, wherein this mechanical regulating device (7,10) acts on the flow-control valve (17) in such a way that, as a function of the change in the eccentricity, the flow-control valve (17) controls the pressure-medium quantity supplied to the hydraulic motor in such a way that the speed of the hydraulic motor is kept constant.Type: GrantFiled: October 1, 1991Date of Patent: June 2, 1992Assignee: Paul Pleiger Maschinenfabrik GmbH & Co. KGInventors: Alfred Marian, Mathias Szewczyk
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Patent number: 5101629Abstract: A hydraulic circuit system comprising a hydraulic-fluid supply source, at least one hydraulic actuator operated by hydraulic fluid from the hydraulic-fluid supply source, a flow control valve for controlling the flow of the hydraulic fluid to be supplied to the actuator and a pressure control element for maintaining the differential pressure across the flow control valve at a predetermined value.Type: GrantFiled: July 2, 1990Date of Patent: April 7, 1992Assignee: Hitachi Construction Machinery Co., Ltd.Inventors: Genroku Sugiyama, Toichi Hirata
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Patent number: 5048295Abstract: In a hydrostatic transmission comprising a pump and a hydraulic motor arranged in a main line having low pressure and high pressure sections, wherein an oil drain line of the hydraulic motor is connected to the low pressure section of the main line, the housing of the hydraulic motor is freed from excessively high pressures in the main line by arranging a valve having an adjustable passage cross-section which decreases with increasing pressure in the main line before--in the direction of flow--the line connection of the oil drain line.Type: GrantFiled: March 15, 1989Date of Patent: September 17, 1991Assignee: Hydromatik GmbHInventor: Arnulf Hoscheler
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Patent number: 5038671Abstract: A control valve is disclosed for use in controlling flow of hydraulic fluid from a hydraulic pump to a plurality of actuators. The control valve includes a valve housing within which are formed control bores, pressure-compensating bores, a feed passage communicating between the pressure-compensating bores, a selected-load pressure transmitting passage communicating between the pressure-compensating bores, a pair of return passages communicating between the control bores and a reservoir tank, control passages communicating respectively between each of the control bores and each of the pressure-compensating bores, and feeding and exhausting passages, as well as actuator ports, communicating between the control bores and the actuators. Control valve spools are slidably mounted, respectively, in the control bores, and pressure-compensating valves are slidably mounted, respectively, the pressure-compensating bores.Type: GrantFiled: April 5, 1989Date of Patent: August 13, 1991Assignee: Diesel Kiki Co., Ltd.Inventor: Katsumi Ueno
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Patent number: 4928487Abstract: A cylinder unit is supplied with pressurized fluid from a hydraulic machine which is variable in speed and/or displacement. The machine may be operated as a pump and as a motor to increase the pressure or, respectively, to decrease the pressure so that the piston of the cylinder unit may be actuated in both directions and, furthermore, the brake energy is recovered by the machine when the piston is driven through an external load. This results in an increased efficiency of the control apparatus for the cylinder unit avoiding any problems arising from heat.Type: GrantFiled: June 5, 1985Date of Patent: May 29, 1990Assignee: Mannesmann Rexroth GmbHInventor: Heinrich Nikolaus
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Patent number: 4863337Abstract: A control system for a working machine which has a boom equipped with a working implement at its forward end and pivoted to a vehicle body movably about a vertical axis, and control valve for controlling the movement of the boom. The system comprises a variable resistor for setting a target position where the boom is to be stopped to produce a setting signal, a sensor for detecting the moved position of the boom to produce a detection signal, differential device for determining the difference between the setting signal and the detection signal to produce a difference signal, a detector for detecting the direction of movement of the boom from the magnitude of the difference signal, a pulse-width modulator for subjecting the difference signal to pulse-width modulation to produce a pulse signal, and a driver for driving the control valve by the pulse signal in the detected direction in proportion to the difference signal.Type: GrantFiled: March 25, 1988Date of Patent: September 5, 1989Assignee: Kubota, Ltd.Inventors: Toshio Ishiguro, Hideaki Mizota, Tuyoshi Aoki
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Patent number: 4850191Abstract: A pump supplies a plurality of consumers each via a directional control valve with pressure balance. When the pump delivery is not adequate, manifesting itself in a dropping of the pump pressure, the pressure balance of the consumer with the highest load pressure is displaced out of the end position of its regulating position into a further control position in which a control pressure line is connected via a throttle point to a discharge so that by means of the throttle point a control pressure is generated which is used for equiproportional reduction of the supply flow to the consumers. This is done either by reducing the stroke of the directional control valves or by acting on the pressure balances in the closure direction.Type: GrantFiled: December 29, 1987Date of Patent: July 25, 1989Assignee: Mannesmann Rexroth GmbHInventors: Norbert Kreth, Martin Schmitt, Armin Stellwagen
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Patent number: 4801245Abstract: One or more throttles are accommodated in a compression line and/or in a suction line to damp surges in reciprocating compressors. The size of the open cross-section of the throttle can be varied. The size is established to prevent surges from exceeding a prescribed limit.Type: GrantFiled: April 8, 1988Date of Patent: January 31, 1989Assignee: Borsig GmbHInventors: Peter de Haas, Robert Ehrich, Reidar Joergensen
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Patent number: 4754603Abstract: A prime-mover driven variable-rate pump of relatively great flow capacity is in delivery and return-circuit connection to an intermittently loaded hydraulic motor. A fixed-rate pump of substantially less capacity is continuously driven by the prime-mover, to charge a hydraulic accumulator, there being a safety relief to sump when a predetermined high-pressure threshold is reached. The accumulator is exclusively connected to the inlet of the variable-rate pump, being isolated by check valves from delivering any reverse flow to the fixed-rate pump and from delivering any reverse flow to the return portion of the motor-driving circuit. In said return portion, and between its check valve and the motor, a "dump" valve is operable for transient diversion of return flow to sump, thereby transiently enabling enhanced load-accelerating torque from the motor; this valve is preferably pressure-operated to "dump" position upon a load-reflecting pressure rise in the supply line from the variable-rate pump to the motor.Type: GrantFiled: July 20, 1987Date of Patent: July 5, 1988Inventor: Alan H. Rosman
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Patent number: 4736585Abstract: An adjustable hydrostatic machine is connected to a pressure line with impressed system pressure. The pressure difference applied at the machine is set at a control valve so that the stroke volume of the machine in idling operation is set to an adjustment belonging to a predetermined load torque. In idling operation the machine is thus operated at large stroke volume with small pressure difference. If it is then necessary to furnish the load torque a switching valve is opened so that at the machine the full pressure difference is immediately applied, the machine can furnish the desired torque and the time loss necessary for setting the machine is eliminated.Type: GrantFiled: March 10, 1986Date of Patent: April 12, 1988Assignee: Mannesmann Rexroth GmbHInventor: Rolf Kordak
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Patent number: 4713936Abstract: A hydraulic motor has its lube drain connected to the motor return line. A motor seal protector valve has a pilot which responds to pressure in the motor return line. Normally, the valve connects system pressure to the motor inlet. High pressure in the return line causes the pilot to move the valve to block the motor feed line and then to connect the motor feed line to sump. In a preferred embodiment, system pressure is connected to the plot to "lock up" the valve in response to return line overpressurization.Type: GrantFiled: November 18, 1985Date of Patent: December 22, 1987Assignee: Deere & CompanyInventors: Dennis R. Barber, Larry M. Delfs, Ronnie F. Burk
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Patent number: 4710106Abstract: The device of this invention has a variable capacity pump, a channel through which the discharged fluid from the pump passes toward an actuator, a variable choke located in the channel and pressure detecting means which detects the pressure difference on opposite sides of the variable choke. The pump varies its volume in relation with the pressure difference detected by the pressure detecting means. The opening area of the channel is varied by the variable choke in relation with the pressure of the fluid being supplied to the actuator, namely the pressure of the fluid flowing downstream of the variable choke. The device of this invention may also have an auxiliary variable choke located in the channel. The auxiliary variable choke can control the amount of fluid being supplied to the actuator in response to the operating condition of the actuator.Type: GrantFiled: November 25, 1985Date of Patent: December 1, 1987Assignee: Nippondenso Co., Ltd.Inventors: Hiroshi Iwata, Masatoshi Kuroyanagi, Masahiko Suzuki, Koichi Moriguchi, Yasuhiro Horiuchi, Kanehito Nakamura
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Patent number: 4708596Abstract: A pressure and delivery regulating device for an adjustable pump includes a directional control valve connected in a discharge conduit and to a control conduit branching from the discharge conduit between the pump and the directional control valve. The control conduit leads to a setting piston for the adjustment of the pump. The directional control valve is controlled by a solenoid which in turn is controlled by a control system consisting of a regulating circuit, a delivery limiting circuit and a control circuit for the solenoid. The output signal from the regulating circuit controls a desired delivery value signal supplied to the delivery limiting circuit. A follow-up circuit connected between the regulating circuit and the delivery limiting circuit corrects the regulating signal and a circuit for producing a direction dependent signal from the actual pressure provides a damping of the regulating circuit.Type: GrantFiled: July 28, 1986Date of Patent: November 24, 1987Assignee: Robert Bosch GmbHInventors: Volker Palm, Berthold Pfuhl
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Patent number: 4696162Abstract: A multi-function valve usable in a hydrostatic transmission and having valve components mounted in a single valve body to provide pressure limiter and high pressure relief functions and with the structure also providing a bypass function and for supply of makeup fluid to the hydrostatic transmission. The multifunction valve has a charge check valve member and a relief valve member in associated relation and movable upon the occurrence of a predetermined pressure differential thereacross to perform control functions. One pressure differential results from a flow through an orifice and with the flow being controlled by a poppet valve member normally held closed by a heavy spring which establishes a system pressure at which the pressure limiter function will occur. With this structure, the pressure limiter function occurs in advance of the high pressure relief function and under the control of a single heavy spring.Type: GrantFiled: July 17, 1986Date of Patent: September 29, 1987Assignee: Sundstrand CorporationInventor: Keith R. Williams
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Patent number: 4685295Abstract: The invention relates to a control unit for a hydraulically operated consumer of the type which is used for operating heavily intermittently and loaded machines such as cranes. The consumer is fed in accordance with a load sensing function with pressurized fluid which depends on the opening of the supply valve but is independent of load pressure variations. The invention is directed to minimizing the lagging of the adjustments to different loading conditions to provide more rapid stabilization. This is done by providing the signal conduit with three branches between the inlet and outlet lines to form a pressure dividing arrangement in which the signal pressure is no longer equal to the load pressure but is composed of parts of the load pressure and the output of a pressure regulating valve in the inlet line of the unit. Upon fluctuation in the load the amount of flow is not kept constant but instead decreases with an increasing load and increases with a drop in the load.Type: GrantFiled: October 1, 1985Date of Patent: August 11, 1987Assignee: Danfoss A/SInventors: Preben Christiansen, Christian Eskildsen, Svend E. Thomsen
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Patent number: 4665699Abstract: A hydrostatic drive with a pump is provided having a delivery line coming from the latter, to which at least one consumer is connected through a branch line, and an adjustable restrictor in the branch line, where the adjusting element of the restrictor is loaded on one side by an arbitrarily regulatable pressure, the improvement comprising means whereby the adjusting element of the restrictor is loaded on the other side by the pressure in the branch line between the restrictor and the consumer.Type: GrantFiled: November 19, 1984Date of Patent: May 19, 1987Assignee: Linde AktiengesellschaftInventor: Alfred Krusche
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Patent number: 4655039Abstract: A hydraulic lifting and lowering system for battery-powered lift trucks includes an electronic control system which reduces or limits operator selected lifting commands in accordance with the current being drawn by an electric motor connected to drive a variable-displacement pump, and in accordance with the state-of-charge of the vehicle battery, to control a proportional valve which meters fluid flow to a lift cylinder.Type: GrantFiled: June 20, 1985Date of Patent: April 7, 1987Assignee: The Raymond CorporationInventors: Paul P. McCabe, James Woolston
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Patent number: 4644749Abstract: A controller for maintaining a motor operation at a desired rotational speed utilizes a phase locked loop that receives input signals from a tachometer coupled to the motor shaft. Reference frequencies for the phase locked loop are generated by a voltage control oscillator in response to voltages selected in accordance with the desired motor speed. These selected voltages are coupled to the motor speed control to establish a motor speed within the lock-in range of the phase locked loop. Tachometric feedback is applied in parallel for the phase locked loop. The open loop drive provided by the selected voltage guarantees degraded open loop control of the motor should the control circuit fall.Type: GrantFiled: March 21, 1983Date of Patent: February 24, 1987Assignee: Sperry CorporationInventor: Richard K. Somes
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Patent number: 4600071Abstract: In order to prevent sudden fluctuations in the supply of hydraulic fluid fed to a power steering or like servo mechanism and to enable the downshifting of a transmission used to drive the pump and an ancillary device such as an alternator, at speeds suited to the specifications of the alternator, a "flow-down" valve induces first and second flow reductions which are separated by an engine speed range which enables the higher downshift speed to be selected at an engine speed suited to the specifications of the alternator. The first flow reduction or flow-down occurs within a relatively narrow engine speed range. This facilitates the above mentioned selection and additionally enables a change from a high power steering assist at low speed to an intermediate one. The second "flow-down" enables a more gradual change from the intermediate assist to a low level one suitable for high speed driving.Type: GrantFiled: October 12, 1984Date of Patent: July 15, 1986Assignee: Nissan Motor Co., Ltd.Inventors: Hisashi Kitahara, Noboru Hattori, Yoshiaki Kato, Nobuteru Hitomi
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Patent number: 4507919Abstract: A fail-safe actuator mechanism has an actuator housing encapsulated within a tank which stores a pressurized fluid media. Ports of the actuator housing are put into selective fluid communication with both the interior and exterior of the encapsulating tank by a valve at selective pressures.Type: GrantFiled: May 17, 1982Date of Patent: April 2, 1985Inventor: Russell G. Smith
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Patent number: 4406123Abstract: The disclosure relates to improvements in a hydraulically-actuated control device used in an operation unit of treatment chair and the like in an interlocking relation with reciprocating movement of a hydraulic piston. The device is of the construction in which two control valves slow in closing and opening operation are disposed in the oil supply and discharge passages leading to a hydraulic cylinder having a hydraulic piston therein so as to prevent shock in starting and stopping of the operation unit by controlling opening and closing of the two control valves and operation of the hydraulic pump disposed in the oil supply passage.Type: GrantFiled: February 18, 1981Date of Patent: September 27, 1983Assignee: Kabushiki Kaisha Morita SeisakushoInventors: Takahiro Matsui, Akifumi Tachibana
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Patent number: 4237926Abstract: A fluid system (10) has a shutoff valve (13) positioned between a fluid tank (11) and the intake side of a pump (12). The valve (13) includes a valve spool (21) movable between a first position at which an inlet port (18) connected to the fluid tank (11) is blocked from communication with an outlet port (19) connected to an intake side of the pump (12) and a second position at which the inlet port (18) is in communication with the outlet port (19). A passage (26) connects the outlet port (19) to a first chamber (23) at one end of the valve spool (21) while a port (27) connects the discharge side of the pump (12) to a second chamber (24) at the opposite end of the valve spool (21). A spring (29) resiliently urges the valve spool (21) to the first position.Type: GrantFiled: January 29, 1979Date of Patent: December 9, 1980Assignee: Caterpillar Tractor Co.Inventor: George W. Walker
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Patent number: 4203292Abstract: A pressurized fluid supply for an auxiliary power steering system includes a regulator valve assembly controlling the output pressure of a fluid supply pump under the opposing influences of the pump discharge pressure and a signal feedback pressure from a fluid operated servomotor. An adjustable bias applied to the regulator valve assembly establishes a low idling discharge pressure for the pump while no steering action is being performed by the servomotor to which the pump is connected by a control valve biased to a flow blocking position.Type: GrantFiled: September 6, 1978Date of Patent: May 20, 1980Assignee: Zahnradfabrik Friedrichshafen, AGInventor: Horst Deininger
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Patent number: 4201053Abstract: A telescoping hydraulic cylinder apparatus for elevator application, wherein telescoping cylinders and a piston rod extend or retract simultaneously, having a compensator pump for automatically replenishing fluid lost due to leakage from the upper cylinders of the apparatus.Type: GrantFiled: November 6, 1978Date of Patent: May 6, 1980Assignee: Dover CorporationInventor: Richard E. Atkey
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Patent number: 4193263Abstract: A fluid control system includes a directional control valve assembly adapted for use in either an open-center or a closed-center configuration. The system is capable of incorporating one or more control sections, each with a manual control valve and its own individually variable flow control mechanism. Each flow control mechanism is independently responsive to section load pressure, and is capable of controlling the flow rate delivered to its section when the control valve spool is biased to a full power position. Each section contains a kickout mechanism for returning the control valve spool to its neutral position at a predetermined pressure.Type: GrantFiled: July 27, 1978Date of Patent: March 18, 1980Assignee: Borg-Warner CorporationInventor: David R. Ille
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Patent number: 4191017Abstract: A motor displacement control system (10) has a variable displacement drive motor (38), an auxiliary motor (30), a source (12) of fluid under pressure for operating the motors (30, 38), a first valve (50) for controlling the displacement of the drive motor (38) and maintaining at least a first pressure level thereto, and a second valve (98) for controlling the displacement of the drive motor (38) in response to operation of the auxiliary motor (30) at a second pressure level and overriding the first valve (50). The system is particularly useful on a motor grader.Type: GrantFiled: February 8, 1979Date of Patent: March 4, 1980Assignee: Caterpillar Tractor Co.Inventor: Joseph E. Dezelan
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Patent number: 4182126Abstract: A servo controlled, proportional valve is connected in parallel with a forklift truck control valve to regulate the speed at which the fork is raised or lowered by shunting the forklift pump output to the hydraulic fluid reservoir during the raising of the fork and by restricting the return flow of fluid from the lift jack during lowering of the fork with the setting of the proportional control valve being servo controlled in response to a fork height sensor.Type: GrantFiled: September 11, 1978Date of Patent: January 8, 1980Assignee: Logisticon, Inc.Inventor: Thomas R. Blakeslee
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Patent number: 4179887Abstract: Two hydraulic brakes or clutches being primary users, are alternately, delayedly, hydraulically energized from a constant volumetric flow rate pump feeding also a secondary user via a pressure controller with a differential piston operated by feedback ducts from the primary users via a throttle valve. The latter valve is bypassed through a check valve for undelayed de-energization. A selector valve is disposed between the branch point for the secondary user and upstream as to energizing fluid from the feedback connection to the primary user. The pressure controller is described further as to several structural details.Type: GrantFiled: April 24, 1978Date of Patent: December 25, 1979Assignee: Mannesmann AktiengesellschaftInventors: Gerhard Ridder, Wilhelm Schafer
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Patent number: 4176522Abstract: A torque responsive apparatus for controlling a fluid actuated control device includes a first shaft connected to a drive motor and a second shaft connected to the first shaft through a coupling device that controls fluid pressure in a hydraulic control system whereby torque delivered to the coupling device effects shifting of the coupling member to vary the size of an opening through which a control fluid is being passed whereby a change in fluid pressure will result which is proportional to the torque of the first shaft.Type: GrantFiled: January 20, 1978Date of Patent: December 4, 1979Assignee: Mark HoltzappleInventors: Mark T. Holtzapple, Robert L. Wehe, Charles G. Myer, William W. Carson