Controlled By Supply Or Exhaust Valve Patents (Class 137/596.13)
  • Patent number: 10539441
    Abstract: A flow or level switch comprises a sensor/switch assembly which is adapted for mounting in connection with either a fitting having an offset defining a channel to detect fluid flow through an orifice into the channel or a tank having a ball float to detect the level of the ball float in the tank. A switch module comprises a control rod which reciprocates and activates a switch unit having a bi-positionable contact member. A follower, which may be in the form of an axle with an angularly fixed projection, engages the control rod to cause the contact member to move.
    Type: Grant
    Filed: May 11, 2018
    Date of Patent: January 21, 2020
    Inventor: Thomas R. Duksa
  • Patent number: 10508746
    Abstract: A spool for a spool valve having a longitudinal axis (L). The spool comprising: a plurality of lands each having a substantially radially extending metering edge and an axially extending circumferential surface; a plurality of grooves separating each of the plurality of the lands; and a guiding section located axially between at least one land and an adjacent groove. The guiding section comprising a plurality of circumferentially spaced guiding surfaces being substantially flush and contiguous with the circumferential surface of the land, wherein the guiding section allows fluid communication between the groove and the metering edge of the land.
    Type: Grant
    Filed: April 27, 2018
    Date of Patent: December 17, 2019
    Assignee: HAMILTON SUNDSTRAND CORPORATION
    Inventors: Marcin Cis, Dominik Gunia
  • Patent number: 10408358
    Abstract: A compensator spool of a load sensing valve device includes a pressure chamber, a compensator throttle portion, a pressure introduction chamber, a pressure introduction port, a maximum load pressure introduction chamber, and a selector valve. A groove is formed around the pressure introduction port, and a groove moves relatively between a passage communicating with an actuator to reduce an opening area of the pressure introduction port when the compensator spool moves.
    Type: Grant
    Filed: October 27, 2015
    Date of Patent: September 10, 2019
    Assignee: KYB Corporation
    Inventors: Shota Mizukami, Takeshi Terao, Akio Matsuura
  • Patent number: 10260532
    Abstract: A smart load-sensing EHA, comprising a variable displacement hydraulic pump, a symmetrical hydraulic cylinder, a feedback module, a pressure-following valve and an execution mechanism. The symmetrical hydraulic cylinder includes a symmetrical plunger, a first cylinder and a second cylinder separated by the plunger. The variable displacement hydraulic pump includes an oil inlet and an oil outlet. An output of the feedback module is to output a greater one of pressures at the first input and the second input to the execution mechanism. The pressure-following valve is connected between the output of the feedback module and an input end of the execution mechanism to reduce an instantaneous flow input to the input end of the execution mechanism and adjust pressure at the input end thereof. The execution mechanism is to receive an output of the feedback module and generate signal for changing displacement of the variable displacement hydraulic pump.
    Type: Grant
    Filed: January 24, 2017
    Date of Patent: April 16, 2019
    Assignee: BEIHANG UNIVERSITY
    Inventors: Zongxia Jiao, Yaoxing Shang, Shuai Wu, Zengning Song, Weiyi Hao
  • Patent number: 10125797
    Abstract: A load sense passage in a load sense hydraulic system may be vented by allowing flow from the load sense passage to a reservoir via a drain passage when a first flow control valve is in a neutral position. This venting may be prevented by preventing flow from the load sense passage to a reservoir via the drain passage when the first flow control valve is in a flow-allowing position.
    Type: Grant
    Filed: September 18, 2015
    Date of Patent: November 13, 2018
    Assignee: Parker-Hannifin Corporation
    Inventors: Brian Slattery, Kevin Lawrence Bresnahan
  • Patent number: 10024443
    Abstract: Arrangements of a flow path to achieve a series circuit, a regeneration circuit and a float/passive regeneration circuit. For example, a valve body having a spool bore, a valve inlet, a plurality of cavities opening into the spool bore and a spool disposed in the spool bore. A first cavity fluidly connected to a tank passage, a second cavity fluidly connected to a first work port, a third cavity fluidly connected to an inlet of another valve, a fourth cavity fluidly connected to a second work port, a fifth cavity fluidly connected to the valve inlet, a sixth cavity fluidly connected to the first work port, a seventh cavity, an eighth cavity fluidly connected to the valve inlet, a ninth cavity fluidly connected to the inlet of the other valve and a tenth cavity fluidly connected to the valve inlet.
    Type: Grant
    Filed: June 8, 2016
    Date of Patent: July 17, 2018
    Assignee: Parker-Hannifin Corporation
    Inventors: Chuck Sensabaugh, Dennis Reynolds, Brian Slattery
  • Patent number: 10006473
    Abstract: This invention provides a hybrid construction machine including a swing structure, a hydraulic pump, a hydraulic swing motor driving the swing structure using hydraulic fluid from the hydraulic pump, an electric swing motor driving the swing structure in conjunction with the hydraulic swing motor, a boom cylinder operated simultaneously with the swing structure at times and driven by the hydraulic fluid from the hydraulic pump, a first directional control valve controlling flow of the hydraulic fluid supplied from the hydraulic pump to the hydraulic swing motor, a second directional control valve controlling the flow of the hydraulic fluid returning from the hydraulic swing motor, and a controller and solenoid pressure reducing valves which prevent operation of the second directional control valve when the boom cylinder is operated simultaneously with the swing structure.
    Type: Grant
    Filed: June 3, 2015
    Date of Patent: June 26, 2018
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Shinji Nishikawa, Kouji Ishikawa, Hidetoshi Satake, Shinya Imura, Shiho Izumi
  • Patent number: 10006472
    Abstract: A construction machine includes: a swing structure (50); a hydraulic pump (1); a hydraulic motor (3) for driving the swing structure (50) using hydraulic fluid from the hydraulic pump (1); an electric motor (14) for driving the swing structure (50) with or without the aid of the hydraulic motor (3); and a hydraulic actuator (16) driven by the hydraulic fluid from the hydraulic pump 1, the hydraulic actuator can be operated together with the swing structure (50). When the swing structure (50) is operated together with the hydraulic actuator (16), only the electric motor (14) is used to swing the swing structure (50).
    Type: Grant
    Filed: October 15, 2013
    Date of Patent: June 26, 2018
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Shinji Nishikawa, Hidetoshi Satake, Shinya Imura, Shiho Izumi, Kouji Ishikawa
  • Patent number: 9821840
    Abstract: A hydraulic control device includes: a hydraulic pump connected in parallel to steering and boom cylinders; a steering control valve that controls the direction of operating oil flowing through the steering cylinders; a boom control valve that connects the hydraulic pump to a tank when the valve is at a neutral position and controls the direction of the oil flowing through the boom cylinders when the valve is at an offset position; a meter-in pressure compensator that increases flow rate of the oil flowing through a variable restrictor of the steering control valve in accordance with pressure in front of and behind the restrictor; and a bleed-off pressure compensator that decreases flow rate of the oil flowing through the boom control valve in accordance with the increase in pressure of the oil flowing through the steering cylinders to maintain the predetermined pressure of the oil in the steering control circuit.
    Type: Grant
    Filed: November 30, 2012
    Date of Patent: November 21, 2017
    Assignee: KABUSHIKI KAISHA KCM
    Inventors: Makoto Ito, Ryo Yamamoto, Kazuto Fujiyama, Hiroyasu Kodera, Shinichiro Tanaka
  • Patent number: 9732863
    Abstract: An end of a first land has a step difference recessing inward of a radial direction of the first land from the edge portion. The step difference has an end point opposite to the edge portion. A throttle portion protrudes from the start point in an axial direction, and includes an outer-peripheral corner (protrusion round portion) having a curved surface protruding in the axial direction and in the radial direction. When an inlet opening starts to be slightly opened, since a hydraulic fluid is throttled when flowing through a second gate opened between a corner of a sleeve and the protrusion round portion, a rapid increasing of a flow quantity of the hydraulic fluid and an instability of a control of the hydraulic fluid can be suppressed.
    Type: Grant
    Filed: February 20, 2015
    Date of Patent: August 15, 2017
    Assignee: DENSO CORPORATION
    Inventors: Kanehisa Nagasaki, Kazuhiro Sasao
  • Patent number: 9523377
    Abstract: A method of controlling a pneumatic actuator for actuation of a pneumatically actuated device. The actuator comprises a piston and a pneumatic cylinder, the piston is arranged to move axially within the pneumatic cylinder. The piston is moved as a function of a pressure in a pressure chamber of the pneumatic cylinder, and the pressure in the pressure chamber is adjusted by a control unit which controls at least a valve and/or a pressure regulator and/or a pressure generating device. A pilot control component, for the control, is determined as a function of at least a sliding friction force and/or at least a static friction force of the pneumatic actuator.
    Type: Grant
    Filed: November 8, 2011
    Date of Patent: December 20, 2016
    Assignee: ZF Friedrichshafen AG
    Inventors: Rupert Kramer, Peter Herter, Franz Bitzer, Roland Mair, Florian Schneider
  • Patent number: 9201430
    Abstract: A manipulator for translating a load along an axis of translation is provided. The manipulator comprises an outer column and a telescoping column positioned adjacent the outer column. The telescoping column is attached to the load and configured to translate the load along the axis of translation. At least one guiding member is mounted between the outer column and the telescoping column, wherein the guiding member is configured to guide the telescoping column as the telescoping column translates along the axis of translation.
    Type: Grant
    Filed: February 27, 2014
    Date of Patent: December 1, 2015
    Assignee: inTEST Corporation
    Inventors: Steven Crowell, Charles Nappen
  • Patent number: 9193046
    Abstract: A hydraulic flow sensing apparatus is provided. The apparatus includes: a manifold; a hole in the manifold in fluid communication with a fluid pathway; a poppet valve in the hole in the manifold configured to move when fluid in the pathway flows; and a proximity switch configured to detect movement of the poppet valve. A method of operating a hydraulic circuit may also be provided.
    Type: Grant
    Filed: August 3, 2012
    Date of Patent: November 24, 2015
    Assignee: SPX FLOW, INC.
    Inventor: Michael T. Landrum
  • Patent number: 9127694
    Abstract: Embodiments of the invention provide a high-reliability, cost-effective electro-hydraulic servo-valve assembly that is not susceptible to failure caused by contaminated fluid. In particular embodiments, the electro-hydraulic servo-valve assembly includes a rotary valve that may be actuated by either a direct-coupled Limited Angle Torque (LAT) motor, a geared, brushless DC motor, or some other rotary electric actuating element with an integrated driver circuit. In particular embodiments, the rotary valve element made up of an outer sleeve element and an inner spool element, with matching ports and slots, respectively.
    Type: Grant
    Filed: August 29, 2012
    Date of Patent: September 8, 2015
    Assignee: Woodward, Inc.
    Inventors: Kevin E. Greeb, Philip A. LaFleur, Jonathan P. Workman, John J. Been
  • Publication number: 20150096638
    Abstract: In a fluid control device, a check valve includes a first valve housing and a first diaphragm. The first diaphragm defines a first valve chamber and a second valve chamber. An exhaust valve includes a second valve housing and a second diaphragm. The second diaphragm defines a third valve chamber and a fourth valve chamber. The check valve is opened and closed by a difference in pressure between the first valve chamber and the second valve chamber. The exhaust valve is opened and closed by a difference in pressure between the third valve chamber and the fourth valve chamber.
    Type: Application
    Filed: December 15, 2014
    Publication date: April 9, 2015
    Inventors: Yukiharu KODAMA, Atsuhiko HIRATA, Yoshihiko SANO, Toshihiko OGURA, Yoshiki DOI
  • Patent number: 8875736
    Abstract: A hydraulic control valve for heavy equipment is provided, which includes a valve body having a supply passage supplied with a hydraulic fluid from a hydraulic pump, ports for supplying the hydraulic fluid to an actuator or receiving the hydraulic fluid from the actuator, tank passages for returning the hydraulic fluid from the actuator to a hydraulic tank, and a first regeneration passage for supplying a part of the returned hydraulic fluid to the supply passage; a spool slidably installed in the valve body in accordance with supply of a pilot signal pressure from an exterior, and controlling flow of the hydraulic fluid supplied to the actuator from the supply passage during shifting; and a regeneration valve installed between the first regeneration passage and the tank passage, and including a piston moved by the hydraulic fluid from the hydraulic pump, a regeneration spool shifted by pressure fluctuation of the supply passage to variably adjust a flow rate of the hydraulic fluid discharged from the first r
    Type: Grant
    Filed: October 7, 2008
    Date of Patent: November 4, 2014
    Assignee: Volvo Construction Equipment Holding Sweden AB
    Inventor: Man Suk Jeon
  • Patent number: 8393348
    Abstract: A control valve has a pressure chamber 24 causing a pressure to act on a valve element 21 of a check valve 20, an oil chamber 39 around the valve 21, a slot 40 formed in the valve element 21 and interconnecting the oil chamber 39 and the pressure chamber 24with each other and, a control valve 25 connected directly to a divergence portion 17 and the oil chamber 39 and capable of permitting or cutting off communication between the divergence portion 17 and the oil chamber 39 and changing an opening degree of the communication, an intra-valve-element passage 42, a slot 41 formed in an outer peripheral wall of the valve element 21 and communicating the passage 42 and the chamber 39 with each other, and a spring-return auxiliary check valve 43 for allowing pressure oil to flow from a supply passage 15 into the intra-valve-element passage 42.
    Type: Grant
    Filed: February 18, 2008
    Date of Patent: March 12, 2013
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Mitsuhisa Tougasaki, Katsumi Ueno
  • Publication number: 20120048410
    Abstract: An oil control valve includes: a housing that is connected to an oil passage via which an oil is fed to and drained from a hydraulic device; an elongated spool that changes a state of oil feeding-drainage for the hydraulic device by moving in the housing; and a drain passage which is formed in the spool such that the drain passage extends in an axial direction of the spool and an outlet of the drain passage is provided at a radial side face of an axial end portion of the spool, and via which the oil that has entered the housing from the hydraulic device is drained, wherein the spool includes an elongated spool body, and an attachment that is separate from the spool body and is fixed at an axial end portion of the spool body.
    Type: Application
    Filed: August 23, 2011
    Publication date: March 1, 2012
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventor: Shinobu Shimasaki
  • Patent number: 7958768
    Abstract: Embodiments of the present invention are directed toward pressure controllers and calibrators for setting or measuring pressures in test devices. In one embodiment, the pressure controller contains a dual reference pressure controller. The dual reference pressure controller is operable to maintain two different pressures relative to a reference pressure. The first pressure being a relatively fixed amount greater than the reference pressure and the second pressure being a relatively fixed amount less than the reference pressure.
    Type: Grant
    Filed: June 24, 2008
    Date of Patent: June 14, 2011
    Assignee: Fluke Corporation
    Inventors: Pierre R. Delajoud, Robert B. Haines, Thomas A. Lohkamp
  • Publication number: 20100018198
    Abstract: The invention relates to a valve arrangement having an adjustable control valve (10), comprising a control slide (12) for actuating at least one consumer connection (A,B), and having an LS control line, wherein the differential pressure of two actuating pressures (Xa, Xb) serves for the actuation of the control slide (12). Due to the fact that the actuating pressures (Xa, Xb) also actuate a logic valve, which in turn influences an additional valve, and/or actuates a pressure scale that is connected upstream to the control valve (10) having the control slide (12), the difference of the two actuating pressures (Xa, Xb) initially displaces the control slide of the control valve, wherein the higher or the lower of the two actuating pressures (Xa, Xb) either actuate the further valve in the form of the additional valve, and/or influences the pressure scale.
    Type: Application
    Filed: January 18, 2008
    Publication date: January 28, 2010
    Inventor: Winfried Rüb
  • Publication number: 20080110509
    Abstract: A load sense valve assembly includes a first valve in flow communication with a pump discharge line, a second valve in flow communication with the first valve, and a third valve in flow communication with the first valve. The first valve can be a solenoid actuated directional control valve. The second and third valves can be hydraulic pilot actuated directional control valves.
    Type: Application
    Filed: August 17, 2007
    Publication date: May 15, 2008
    Inventor: Leonard H. Hancock
  • Publication number: 20080023084
    Abstract: The present invention discloses a piping design for a high density plasma process chamber, wherein an extra pipe is added to between a process chamber and a mass flow controller, and the extra pipe together with a pump is used to drain out the gas, which cannot be monitored by the mass flow controller and survives in a gas injection pipe, lest the remaining gas pollute the deposited film or react with the process gas to induce an explosion in the succeeding deposition process.
    Type: Application
    Filed: March 28, 2007
    Publication date: January 31, 2008
    Inventors: Ping-Yi Chang, Xiao-Ping Zhang
  • Patent number: 7263924
    Abstract: To simplify a circuit structure and a path structure in a hydraulic circuit having a pilot check valve and an overload relief valve and to reduce the size of a gear. The hydraulic circuit includes a pump port; a tank port; a first actuator port; a second actuator port; a first supply and discharge port; a second supply and discharge port; a direction changing valve; a first pilot check valve; a second pilot check valve; a first pilot path; and a first overload relief valve. The direction changing valve has a neutral position to communicate the first supply and discharge port with the tank port. The first overload relief valve is arranged in parallel with the first pilot check valve and is arranged between the first supply and discharge port and the first actuator port.
    Type: Grant
    Filed: March 29, 2006
    Date of Patent: September 4, 2007
    Assignee: Nabtesco Corporation
    Inventor: Kensuke Ioku
  • Patent number: 6994116
    Abstract: A directional control valve for a hydraulic load has, in a piston bore of a valve housing, a control piston which can be displaced axially in opposite directions from a central position and which has first fine control grooves for opening a connection between a load chamber and a feed chamber. There are second fine control grooves for opening a connection between a load chamber and a discharge chamber of the piston bore under control. In its central position, there is a restricted relief connection from a load chamber to the discharge chamber via the control piston. The restricted relief connection is obtained via a recess in the control piston, independently of the second fine control grooves.
    Type: Grant
    Filed: January 25, 2002
    Date of Patent: February 7, 2006
    Assignee: Bosch Rexroth AG
    Inventor: Peter Büttner
  • Patent number: 6971407
    Abstract: The invention concerns a hydraulic valve arrangement with a supply connection arrangement, which has a high-pressure connection (P) and a low-pressure connection (T), a working connection arrangement, which has two working connections (A, B), which can be connected with a consumer, a directional valve and a compensation valve arranged between the directional valve and the supply connection arrangement, the pressure outlet of the compensation valve being connected with a pressure inlet of the directional valve. It is endeavoured to avoid dangerous situations, which occur because of uncontrolled pressures. For this purpose, it is ensured that the compensation valve has a relief outlet, which can be connected with the pressure outlet.
    Type: Grant
    Filed: December 12, 2003
    Date of Patent: December 6, 2005
    Assignee: Sauer-Danfoss APS
    Inventors: Thorkild Christensen, Carsten Christensen, Siegfried Zenker
  • Patent number: 6964281
    Abstract: An assembly of a plurality of hydraulic control valves is housed in a single-piece body. For each control valve, a spool bore and an aperture for a pressure compensation valve are provided in the monolithic body. Each spool bore is connected to several return passages and a supply passage that extend through the monolithic body. A pair of workports also is connected to each spool bore. A relief valve return passage also extends through the monolithic body and where needed, apertures for pressure relief valves extend from a surface of the monolithic body intersecting the relief valve return passage and a given workport. A load sense passage and a second supply passage also are formed in the monolithic body.
    Type: Grant
    Filed: February 7, 2003
    Date of Patent: November 15, 2005
    Assignee: Husco International Inc.
    Inventor: Gary J. Pieper
  • Patent number: 6915729
    Abstract: The present invention relates to a variable flow control apparatus for an actuator of a heavy construction equipment capable of implementing constant flow of hydraulic fluid from a hydraulic pump to an actuator even when a pilot pressure capable of driving a seat valve openably and closably installed in a discharge flow path of the hydraulic pump exceeds a certain pressure level.
    Type: Grant
    Filed: November 18, 2003
    Date of Patent: July 12, 2005
    Assignee: Volvo Construction Equipment Holding Sweden AB
    Inventor: Jin Wook Kim
  • Publication number: 20040099316
    Abstract: A hydraulic control device (10, 90) for load pressure-independent control of a double-acting motor, in which by replacing the pressure balance regulator throttle slide valve element (68, 93) but using the same housing (13), the control device can be converted from a directional-control valve (11) with a primary individual pressure balance regulator (12) for load pressure-independent control to a directional-control valve (91) with a secondary individual pressure balance regulator (92) for an oil flow distribution in the event of undersupply. To this end, in a second longitudinal bore (41) containing the control pressure opening (68, 93), the housing (13) has three axially spaced infeeds of control pressure openings (51, 52, 53), which can be activated differently through interchangeable installation of a sealing plug (66) and a stopper (67) and, together with the respective throttle slide valve element, constitute a primary pressure balance regulator (12) or a secondary pressure balance regulator (92).
    Type: Application
    Filed: December 2, 2002
    Publication date: May 27, 2004
    Inventor: Wolfgang Koetter
  • Patent number: 6532989
    Abstract: A hydraulic distributor that has a regulating balance including a housing hollowed in the distributor body and containing coaxially a fixed central core. A tubular plunger is interposed sliding freely, coaxially, between the core and the housing and co-operates with a lateral orifice connected to a working orifice. The core and the plunger define between them an annular chamber. The plunger has a first radial annular surface subjected to the highest charge pressure (LS) and a second annular surface subjected to the pressure of the intake fluid. A central passage in the core constitutes a first orifice emerging at one end of the housing exposed to the highest charge pressure (LS). A second orifice emerges in the annular chamber and a third orifice is located opposite the other end of the housing and remains closed by the plunger as long as the charge pressure of the distributor is below the highest charge pressure (LS).
    Type: Grant
    Filed: September 7, 2001
    Date of Patent: March 18, 2003
    Assignee: Mannesmann Rexroth S.A.
    Inventor: Wolfgang Kauss
  • Patent number: 6505645
    Abstract: A valve assembly has a single piece body that houses a plurality of hydraulic valves. Each valve includes a spool which controls the flow of fluid between a pair of work ports in one side of the body and a pump inlet and a tank outlet. The valves are operated by selectively applying pressurized fluid to one end or the other of the spool. That pressure is provided by a conduit or a pilot valve that is attached to a control port in the one side of the body. Because the majority of the connections to the valve assembly are made to the one side of the body access is only required to that side.
    Type: Grant
    Filed: October 8, 2001
    Date of Patent: January 14, 2003
    Assignee: HUSCO International, Inc.
    Inventors: Andreas S. Pack, Eric N. Griesbach, James E. Olsen
  • Patent number: 6314997
    Abstract: A multiple valve apparatus is formed of a priority valve mechanism for dividing an operating liquid into a priority flow and a surplus flow, at least one switching valve mechanism attached to the priority valve mechanism, a parallel line for guiding the surplus flow discharged from the priority valve mechanism to an input port of the at least one switching valve mechanism, a tank line for discharging the operating liquid to a tank, and an urgent valve situated between the parallel line and the tank line. The urgent valve is operated in a predetermined condition to regulate an operation actuated by the surplus flow through the at least one switching valve mechanism. Therefore, the supply of the operating fluid only to the switching mechanism can be stopped or regulated by this simple structure, and an automatic stop or regulating function of an actuator can be achieved in the apparatus.
    Type: Grant
    Filed: May 4, 2000
    Date of Patent: November 13, 2001
    Assignee: Shimadzu Corporation
    Inventor: Shigeru Yamashita
  • Patent number: 6267141
    Abstract: A hydraulic directional control valve with a regulating balance comprising a plunger which can be displaced in a housing (13) under the action of a differential pressure (&Dgr;p) between the intake pressure (P) and the highest load pressure (LS), and which is designed to open, in proportion to this differential (&Dgr;p), a lateral orifice of the housing linked to a working orifice (A, B) of the directional control valve; the wall of the housing and/or the plunger is provided with a calibrated passage linking the intake of fluid at pressure (P) and the lateral orifice when the plunger is pushed back into an end position by the pressure (LS) exceeding the intake pressure (P); consequently, in spite of the excess value of the pressure (LS) intended to inhibit operation of the directional control valve, hydraulic fluid is delivered to the lateral orifice at a low rate and allows the hydraulic receiver controlled by the hydraulic directional control valve to be displaced at a low rate.
    Type: Grant
    Filed: January 19, 2000
    Date of Patent: July 31, 2001
    Assignee: Mannesmann Rexroth S.A.
    Inventor: Michel Rivolier
  • Patent number: 6192929
    Abstract: The present invention provides a hydraulic controller comprising: a plurality of switching spools; a plurality of cylinder ports of a switching valve; a compressed oil passage common to the switching valves having an intermediate chambers, at least a check valve in correspondence with at least a part of said switching spools, and said check valve being positioned between said intermediate chambers and said cylinder ports, so that said switching spools being positioned in a neutral position to close said passage and also being movable to adjust opening degree of said passage, wherein auxiliary ports are provided between the cylinder ports and a tank line; flow rate adjusters are also provided between the auxiliary ports and the tank line for adjusting an opening degree of the passage; pressure detectors are provided in the switching valves for detecting pressures of oils in the intermediate chambers; a maximum pressure selector operatively linked to said pressure detectors for selecting a maximum pressure from
    Type: Grant
    Filed: April 27, 1999
    Date of Patent: February 27, 2001
    Assignee: Toshiba Machine Co., Ltd.
    Inventor: Satoshi Matsumoto
  • Patent number: 6176261
    Abstract: In a hydraulic control device for the direction control of at least one highest hydraulic pressure hydro-motor with working pressures above about 400 bar from a pressure source the hydro-motor is connectable via at least one consumer line and two leakage-free black/white directional seated valves selectively with said pressure source or a return line, within in said consumer line a load holding blocking valve is provided in leakage-free seated valve design and where in-between said pressure source and said return line a 2/2 idling or shunting directional seated valve having a hydraulic actuation is provided which in its blocking position is leakage-free from the pressure source towards said return line and in each switching position is leakage-free between said hydraulic actuation and said return line, and wherein said hydraulic actuation of said idling directional seated valve between said load holding blocking valve and one of said directional seated valves is connected with said consumer line.
    Type: Grant
    Filed: June 10, 1999
    Date of Patent: January 23, 2001
    Assignee: Heilmeier & Weinlein Fabrik F. Oel-Hydraulik GmbH & Co. KG
    Inventor: Martin Heusser