US3857404A - Hydraulically operated lock valve assembly - Google Patents

Hydraulically operated lock valve assembly Download PDF

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Publication number
US3857404A
US3857404A US00355473A US35547373A US3857404A US 3857404 A US3857404 A US 3857404A US 00355473 A US00355473 A US 00355473A US 35547373 A US35547373 A US 35547373A US 3857404 A US3857404 A US 3857404A
Authority
US
United States
Prior art keywords
bore
valve assembly
lock valve
ports
valve
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00355473A
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English (en)
Inventor
H Johnson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Caterpillar Inc
Original Assignee
Caterpillar Tractor Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Caterpillar Tractor Co filed Critical Caterpillar Tractor Co
Priority to US00355473A priority Critical patent/US3857404A/en
Priority to JP49021573A priority patent/JPS5750987B2/ja
Priority to BR1841/74A priority patent/BR7401841D0/pt
Priority to CA196,630A priority patent/CA1001925A/en
Priority to GB1819674A priority patent/GB1399446A/en
Priority to BE143827A priority patent/BE814439A/xx
Application granted granted Critical
Publication of US3857404A publication Critical patent/US3857404A/en
Assigned to CATERPILLAR INC., A CORP. OF DE. reassignment CATERPILLAR INC., A CORP. OF DE. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: CATERPILLAR TRACTOR CO., A CORP. OF CALIF.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/01—Locking-valves or other detent i.e. load-holding devices
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/2496—Self-proportioning or correlating systems
    • Y10T137/2544—Supply and exhaust type

Definitions

  • Many earthmoving machines employ double-acting hydraulic jacks for adjusting machine work implements.
  • the jacks are usually controlled by spool type valves which direct fluid under pressure to either end of the cylinder while simultaneously exhausting fluid from the opposite end.
  • Spool valves are commonly plagued by a tendency to leak, particularly after slight wear has taken place. This leaking around the valve spool causes the hydraulic jack to have a tendency to drift. Although slight drifting is not detrimental to the operation of most earthmoving machines, it can become a problem on grading and finishing machines which require precise blade and/or wheel positioning.
  • a lock valve is commonly employed in the hydraulic circuit between the control valve and the hydraulic cylinder.
  • the lock valve prevents return flow from either end of the cylinder when the control valve is in theneutral position.
  • Such lock valves frequently utilize a pair of conventional ball type check valves which are highly effective in blocking flow from the cylinder.
  • these check valves eg. when the ball check is opened, as by a piston responding to fluid pressure, the opening tends to be very abrupt. This makes it difficult to control the fluid flow and results in a tendency to overshoot. If there happens to be a pressure head in the return line, the tendency to overshoot or overrun is increased. This uncontrolled fluid flow makes it very difficult to make the fine adjustments necessary for precise blade or wheel positioning.
  • Another object of the present invention is to provide a lock valve for a hydraulic jack.
  • a further object of the present invention is to provide a lock valve having means for metering the flow of fluid from a hydraulic jack.
  • Still another object of the present invention is to provide a lock valve having valve checks and means operative to unseat said valve checks, which unseating means provide graduated metering of fluid from the jack cylinder.
  • a still further object of the present invention is to provide a lock valve in which the means operative to unseat the valve checks are so dampened that the valve is stabilized during high jack loads.
  • Still a further object of the present invention is to provide a lock valve including one-way choke means in addition to metering means, which choke means cooperate with the metering means to control fluid flow from the hydraulic jack.
  • a lock valve assembly for controlling a hydraulic jack is provided with metering means operative during unseating of check valves of the assembly to provide precise control over positioning of the hydraulic jack under various load conditions.
  • FIG. 1 is a view in cross section of a lock valve in accordance with the present invention shown in combination with a fluid circuit and hydraulic jack which are illustrated schematically;
  • FIG. 2 is a section taken generally along lines 11 II of FIG. 1;
  • FIG. 3 is an enlarged, detailed view of one of the check valves of FIG. 2.
  • a lock valve embodying the principles of the present invention is generally indicated by the reference numeral 10.
  • the valve is shown in combination with a manually actuatable control valve 11 which directs fluid under pressure to either end of a double acting hydraulic jack 12.
  • This control system may be employed for adjusting the movement of a work load or implement mounted on an earthmoving vehicle.
  • Pressurized fluid is drawn from a tank 14 by a pump 13 and directed to the manually actuatable control valve 11 through conduit 16. Fluid exhausted from the control valve 11 is returned to the tank 14 by conduit 17. A relief valve 18, connecting conduit 16 to the tank 14, relieves excessive pressure in the hydraulic system.
  • the manually actuatable control valve 11 serves to selectively direct fluid under pressure to conduits 26 and 27 and to opposite ends of the hydraulic jack 12 through conduits 36 and 37.
  • the assembly Interposed between conduits 26 and 36 leading to the rod end of the jack l2 and between conduits 27 and 37 leading to the head end of the jack 12 is the lock valve assembly of the present invention.
  • the assembly indicated by reference numeral 10, includes a valve housing 19, provided with an elongated cylindrical bore 20 having a first pair of counterbores 21 and 22 disposed at opposite ends thereof.
  • a pair of ports 23 and 24 connect the bore 20 with the control valve 11 by means of previously mentioned conduits 26 and 27.
  • Both conduits 26 and 27 have a fitting screw 28 threadably secured within their respective ports.
  • a choke valve 29 is disposed in each port above the screw 28.
  • the choke 29 defines an annular disc having a plurality of reliefs 31 and a centrally disposed aperture 32.
  • a pair of passages 34 and 35 connect counterbores 21 and 22 with the rod and head end of the jack 12 by means of conduits 36 and 37.
  • a crossover relief valve mechanism is disposed in bore 38 and includes an annular member 42 having an end screw 43 threadably secured within the open end of the bore 38.
  • a recess 44 provided in the outer end of the annular member 42 connects the valve 41 with passage 34.
  • An axial passage 46 extending inwardly from the inner end of the annular member 42 communicates with passage 34 by means of radial passages 47.
  • the relief valve 41 includes a valve element 48 having a conical tip 49 which is normally seated in the open end of the axial passage 46 by a spring 51.
  • the relief valve 41 prevents overpressurization of the rod end of the cylinder due to heavy external loads and operates whenever there is sufficient pressure in passage 34 to unseat valve element 48. When this happens, the valve 41 admits fluid from passage 34 and returns it to bore 20 by means of passage 39.
  • a plug 52 threadably secured in each of counterbores 21 and 22, has a recess 53 formed in the inner end thereof.
  • a radial vent passage 56 formed in the plug 52 intermediate its ends communicates with the recess 53 and bleeds off residual fluid pressure in the system prior to removal of the plug 52 during disassembly.
  • a pair of identical check valve assemblies are interposed between port 23 and passage 34 leading to the rod end of the jack 12 and between port 24 and passage 35 leading to the head end of the jack 12.
  • the two assemblies are located in bore 20.
  • Check valve assembly 57 includes an annular member 59 pressed or otherwise sealingly disposed in the end of bore 20.
  • the annular member 59 has a plurality coaxial bores 61, 62 and 63 with bore 63 extending inwardly from the outer end and terminating in an annular valve seat 64.
  • the outer end of annular member 59 defines a reduced diameter portion 66 having a plural ity of radial passages 67 and vent passages 68 connecting bore 63 with passage 34.
  • the inner end of annular member 59 defines an annular recess 69 which communicates with the control valve 11 by means of port 23 and conduit 26.
  • a plurality of radial passages 71 connect the annular recess 69 with bore 61.
  • the check valve assembly 57 further includes a ball check or element 72 disposed in bore 63 and urged against the valve seat 64 by a compression spring 73. A close fit between the ball check 72 and the bore 63 provides lateral stability to the check valve assembly. The compression spring 73 biasing the ball check 72 is disposed in bore 63 and the recess of plug 52.
  • a double-ended actuator piston 74 slidably disposed in the bore 20 between the check valve assemblies 57 and 58, forms a pair of variable volume chambers 76 and 77.
  • the piston 74 is provided with a pair of plungers 78 and 79 projecting from opposite ends thereof.
  • Each plunger is formed with an enlarged land portion 81 disposed substantially midway between the center of the piston 74 and outer end of the plunger.
  • the enlarged land 81 has a diameter slightly less than the diameter of the bore 61.
  • Both plungers 78 and 79 terminate in a valve metering head 82 adapted to engage and unseat the valve check in the return line and to meter fluid flow in the line.
  • the head 82 so regulates the flow through the return line as to make it proportional to the flow through the input line.
  • the valve head 82 includes a land portion 83 and first and second tapered sections 84 and 86.
  • the land 83 defines the outermost end portion of the valve head 82 and has a diameter slightly less than the diameter of bore 62. These dimensions allow the land 83 to cooperate with the bore 62 and substantially block the flow of fluid through the check valve 57 during the initial unseating of the ball 72.
  • the first and second tapered sections 84 and 86 disposed between the land 83 and the plunger 78, comprise conical surfaces having increasing angles of metering in the direction of the piston 74.
  • the metering angle of the first tapered section 84 is designated A and the metering angle of the second tapered section 86 is designated B.
  • A is 7 and B is 13.
  • the first tapered section 84 having a shallow angle, meters flow in situations where a pressure head exists in the return line due to heavy loads on the jack 12.
  • the second tapered section 86 having a steeper angle which increases the effective area of the orifice, meters flow in situations where the pressure in the return line is minimal.
  • neutral position is defined as the position required to maintain a work load or implement in a fixed location.
  • the main control valve 11 is positioned to direct fluid through port 24 and radial passages 71 into bore 61 and volume chamber 77. This initial fluid pressure in the bore 61 and chamber 77 is exerted agaisnt both the actuator piston 74 and the ball check 72 of check valve assembly 58.
  • the pressure and flow available in port 24 is communicated to the head end of the jack 12 by way of passage 35 and conduit 37.
  • the actuator piston 74 is moved to the left and the valve head 82 on the plunger 78 engages and unseats the ball check 72 of check valve assembly 57.
  • the land 83 of the valve head is sufficiently positioned within the bore 62 to block fluid flow from the rod end of the cylinder. With the flow blocked, pressure continues to build up in the chamber 77 and cause further leftward movement of the actuator piston 74 until the land 83 passes through the bore 62.
  • one of the tapered sections commences metering fluid exhausted from the rod end of the cylinder and thereby prevents any sudden uncontrolled flow during the initial unseating of the ball check 72.
  • the rate of metering return flow is proportional to the volume of fluid directed to the input line.
  • fluid in the bore 63 is vented into the return line by passage 68 to prevent a hydraulic block.
  • the jack 12 may be required to support a load of sufficient weight as to generate high fluid pressure in the return line of the cylinder. For example, if an external load is pulling on the rod, a pressure head, generated in conduit 36 and pas sages 34 will be brought to bear against the ball check 72 of check valve assembly 57. To extend the jack 12 under these conditions, sufficient fluid pressure must be built up in chamber 77 to move the actuator piston 74 to the left and overcome the pressure head holding the ball check 72 closed.
  • the first tapered section 84 provides a small area orifice for metering the flow. Since the amount of flow through a given sized orifice increases proportionally with increase in fluid pressure, the first tapered section is effective in maintaining a flow rate proportional to the flow rate on the input side of the cylinder.
  • valve head 82 will pass through the bore 62 sufficiently for the second tapered section 86 to meter the fluid flow, or in some cases, sufficiently to provide unrestricted flow.
  • the flow in the supply line raises the choke 29 disposed in the supply port 24 and permits unrestricted flow through the port 24.
  • Return flow through the exhaust port 23 causes the choke 29 disposed in this port 23 to be seated against the fitting screw 28 secured within the port 23. This causes the full flow of exhausted fluid to pass through the central aperture 32 in the choke 29.
  • This restriction in the return line cooperates with the first tapered section 84 to control a heavy load on jack [2 and to prevent cavitation of the jack 12 when the control valve 11 is actuated.
  • a lock valve assembly having means for metering fluid flow to and from a hydraulic cylinder in a manner insuring smooth and controlled functioning of the hydraulic jack.
  • a lock valve assembly for controlling fluid flow in a hydraulic jack having inlet and outlet means for selectively supplying fluid to either end of the jack cylinder while exhausting fluid from the opposite end comprising:
  • first check valve means disposed in said bore between one of said first ports and one of said second ports;
  • second check valve means disposed in said bore between the other of said first port and the other of said second port;
  • each of said first and second check valve means including a passage communicating between each of said respective first and second ports, a valve seat surrounding said passage, and a valve element engaging said seat normally for blocking fluid flow from said second pair of ports to said first pair of ports;
  • an actuator piston reciprocally disposed in said bore between said first pair of ports and having a pair of plungers extending axially from opposite ends thereof, said plungers terminating in metering head means operative to engage and unseat either check valve element upon endwise movement of the piston, said metering head means being shaped to provide separate metering portions cooperating with said valve passage for regulating fluid flow through the check valves.
  • the lock valve assembly of claim 5 including oneway choke means disposed in the first pair of ports for restricting fluid flow in the return direction from said lock valve.
  • said damping means comprises an enlarged land disposed substantially midway between the piston and the outer end of the plunger, said land extending into and cooperating with the bore of a sleeve extending from said check valve means.
  • the lock valve assembly of claim 1 including oneway choke means disposed in said first pair of ports for restricting fluid flow in the return direction from said lock valve.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Mechanically-Actuated Valves (AREA)
US00355473A 1973-04-30 1973-04-30 Hydraulically operated lock valve assembly Expired - Lifetime US3857404A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US00355473A US3857404A (en) 1973-04-30 1973-04-30 Hydraulically operated lock valve assembly
JP49021573A JPS5750987B2 (zh) 1973-04-30 1974-02-25
BR1841/74A BR7401841D0 (pt) 1973-04-30 1974-03-11 Conjunto de valvula de bloqueamento atuada hidraulicament
CA196,630A CA1001925A (en) 1973-04-30 1974-04-02 Hydraulically operated lock valve assembly
GB1819674A GB1399446A (en) 1973-04-30 1974-04-25 Hydraulic lock valve assembly
BE143827A BE814439A (fr) 1973-04-30 1974-04-30 Ensemble de valve de blocage actionne hydrauliquement

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00355473A US3857404A (en) 1973-04-30 1973-04-30 Hydraulically operated lock valve assembly

Publications (1)

Publication Number Publication Date
US3857404A true US3857404A (en) 1974-12-31

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ID=23397543

Family Applications (1)

Application Number Title Priority Date Filing Date
US00355473A Expired - Lifetime US3857404A (en) 1973-04-30 1973-04-30 Hydraulically operated lock valve assembly

Country Status (6)

Country Link
US (1) US3857404A (zh)
JP (1) JPS5750987B2 (zh)
BE (1) BE814439A (zh)
BR (1) BR7401841D0 (zh)
CA (1) CA1001925A (zh)
GB (1) GB1399446A (zh)

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3943968A (en) * 1975-01-06 1976-03-16 Parker-Hannifin Corporation Combination lock and relief valve for hydraulic systems
US4012031A (en) * 1975-03-25 1977-03-15 Affiliated Hospital Products, Inc. Lock valve flow control arrangement
US4103699A (en) * 1976-07-16 1978-08-01 Avon Enterprises, Inc. Fluid cylinder mounted lock out valve device
US4114516A (en) * 1976-10-15 1978-09-19 Caterpillar Tractor Co. Anti-cavitation and pressure modulating relief valve for controlling hydraulic cylinders
WO1981000598A1 (en) * 1979-08-30 1981-03-05 Caterpillar Tractor Co Selectively actuatable fluid control system for a work implement
US4286432A (en) * 1979-08-30 1981-09-01 Caterpillar Tractor Co. Lock valve with variable length piston and hydraulic system for a work implement using the same
WO1981003208A1 (en) * 1980-05-01 1981-11-12 Boeing Co Integral hydraulic blocking and relief valve
US4344287A (en) * 1979-08-23 1982-08-17 Caterpillar Tractor Co. Volume compensation for hydraulic circuits
US4461449A (en) * 1980-05-01 1984-07-24 The Boeing Company Integral hydraulic blocking and relief valve
US4667570A (en) * 1984-12-21 1987-05-26 The Boeing Company Integral hydraulic blocking and relief valve
US5163352A (en) * 1990-10-26 1992-11-17 Shin Caterpillar Mitsubishi Ltd. Cylinder control unit
EP0969212A3 (de) * 1998-06-30 2000-04-05 Weber-Hydraulik GmbH Vorspann-Rückschlagventil
US6098647A (en) * 1996-02-28 2000-08-08 Beringer-Hydraulik Ag Load-holding brake valve
US6116868A (en) * 1999-03-01 2000-09-12 Lu; Chung-Tai Multi-faceted valve head for hydraulic pump
US6131610A (en) * 1996-11-22 2000-10-17 Smc Kabushiki Kaisha Speed controller with pilot check valve
US20040013540A1 (en) * 2002-07-16 2004-01-22 Giorgio Gai Oil pressure operated pump for marine steering gears
KR100430398B1 (ko) * 2000-12-26 2004-05-04 볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비 건설기계용 낙하방지장치
US8147364B2 (en) 2006-03-28 2012-04-03 Toyota Jidosha Kabushiki Kaisha Flow rate regulation valve, rotating body, and belt-type stepless transmission
CN114294280A (zh) * 2021-12-26 2022-04-08 浙江海宏液压科技股份有限公司 工作阀片及多路阀
US12085099B1 (en) * 2020-06-18 2024-09-10 Vacuworx Global, LLC Flow control block for use with a vacuum material handler

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0310622Y2 (zh) * 1985-04-30 1991-03-15

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2506008A (en) * 1947-01-17 1950-05-02 Bruno F Arps Hydraulic control valve
US2691964A (en) * 1953-02-27 1954-10-19 Ford Motor Co Dual action hydraulic control valve
US2720755A (en) * 1952-09-04 1955-10-18 Vickers Inc Power transmission
US2959190A (en) * 1957-02-25 1960-11-08 Bendix Corp Control valve having operating position hold
US3145734A (en) * 1961-10-06 1964-08-25 Borg Warner Pressure compensated flow control valve
US3198088A (en) * 1963-08-13 1965-08-03 Caterpillar Tractor Co Fluid motor control system
US3250185A (en) * 1964-03-23 1966-05-10 Hydraulic Unit Specialities Co Circuit control valve instrumentality
US3563261A (en) * 1968-06-12 1971-02-16 Mcconnel F W Ltd Lockout valve assemblies for hydraulic control systems
US3587399A (en) * 1969-05-02 1971-06-28 Deere & Co Control valve means for a two-way hydraulic cylinder
US3648968A (en) * 1969-08-07 1972-03-14 Hamilton Co Fluid flow control mechanism

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2506008A (en) * 1947-01-17 1950-05-02 Bruno F Arps Hydraulic control valve
US2720755A (en) * 1952-09-04 1955-10-18 Vickers Inc Power transmission
US2691964A (en) * 1953-02-27 1954-10-19 Ford Motor Co Dual action hydraulic control valve
US2959190A (en) * 1957-02-25 1960-11-08 Bendix Corp Control valve having operating position hold
US3145734A (en) * 1961-10-06 1964-08-25 Borg Warner Pressure compensated flow control valve
US3198088A (en) * 1963-08-13 1965-08-03 Caterpillar Tractor Co Fluid motor control system
US3250185A (en) * 1964-03-23 1966-05-10 Hydraulic Unit Specialities Co Circuit control valve instrumentality
US3563261A (en) * 1968-06-12 1971-02-16 Mcconnel F W Ltd Lockout valve assemblies for hydraulic control systems
US3587399A (en) * 1969-05-02 1971-06-28 Deere & Co Control valve means for a two-way hydraulic cylinder
US3648968A (en) * 1969-08-07 1972-03-14 Hamilton Co Fluid flow control mechanism

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3943968A (en) * 1975-01-06 1976-03-16 Parker-Hannifin Corporation Combination lock and relief valve for hydraulic systems
US4012031A (en) * 1975-03-25 1977-03-15 Affiliated Hospital Products, Inc. Lock valve flow control arrangement
US4103699A (en) * 1976-07-16 1978-08-01 Avon Enterprises, Inc. Fluid cylinder mounted lock out valve device
US4114516A (en) * 1976-10-15 1978-09-19 Caterpillar Tractor Co. Anti-cavitation and pressure modulating relief valve for controlling hydraulic cylinders
US4344287A (en) * 1979-08-23 1982-08-17 Caterpillar Tractor Co. Volume compensation for hydraulic circuits
US4286432A (en) * 1979-08-30 1981-09-01 Caterpillar Tractor Co. Lock valve with variable length piston and hydraulic system for a work implement using the same
US4341149A (en) * 1979-08-30 1982-07-27 Caterpillar Tractor Co. Selectively actuatable fluid control system for a work element
WO1981000598A1 (en) * 1979-08-30 1981-03-05 Caterpillar Tractor Co Selectively actuatable fluid control system for a work implement
WO1981003208A1 (en) * 1980-05-01 1981-11-12 Boeing Co Integral hydraulic blocking and relief valve
US4461449A (en) * 1980-05-01 1984-07-24 The Boeing Company Integral hydraulic blocking and relief valve
US4667570A (en) * 1984-12-21 1987-05-26 The Boeing Company Integral hydraulic blocking and relief valve
US5163352A (en) * 1990-10-26 1992-11-17 Shin Caterpillar Mitsubishi Ltd. Cylinder control unit
US6098647A (en) * 1996-02-28 2000-08-08 Beringer-Hydraulik Ag Load-holding brake valve
US6293180B1 (en) 1996-11-22 2001-09-25 Smc Kabushiki Kaisha Speed controller with pilot check valve
US6296015B1 (en) 1996-11-22 2001-10-02 Smc Kabushiki Kaisha Speed controller with pilot check valve
US6131610A (en) * 1996-11-22 2000-10-17 Smc Kabushiki Kaisha Speed controller with pilot check valve
EP0969212A3 (de) * 1998-06-30 2000-04-05 Weber-Hydraulik GmbH Vorspann-Rückschlagventil
US6116868A (en) * 1999-03-01 2000-09-12 Lu; Chung-Tai Multi-faceted valve head for hydraulic pump
KR100430398B1 (ko) * 2000-12-26 2004-05-04 볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비 건설기계용 낙하방지장치
US20040013540A1 (en) * 2002-07-16 2004-01-22 Giorgio Gai Oil pressure operated pump for marine steering gears
US6984113B2 (en) * 2002-07-16 2006-01-10 Ultraflex S.P.A. Oil pressure operated pump for marine steering gears with a valve set shell with valves separately capable of assembly with the valve housing
US8147364B2 (en) 2006-03-28 2012-04-03 Toyota Jidosha Kabushiki Kaisha Flow rate regulation valve, rotating body, and belt-type stepless transmission
CN101410660B (zh) * 2006-03-28 2012-06-27 丰田自动车株式会社 流量调节阀、旋转体以及带式无级变速器
US12085099B1 (en) * 2020-06-18 2024-09-10 Vacuworx Global, LLC Flow control block for use with a vacuum material handler
CN114294280A (zh) * 2021-12-26 2022-04-08 浙江海宏液压科技股份有限公司 工作阀片及多路阀
CN114294280B (zh) * 2021-12-26 2024-04-09 浙江海宏液压科技股份有限公司 工作阀片及多路阀

Also Published As

Publication number Publication date
BR7401841D0 (pt) 1974-10-29
CA1001925A (en) 1976-12-21
GB1399446A (en) 1975-07-02
BE814439A (fr) 1974-10-30
JPS501275A (zh) 1975-01-08
JPS5750987B2 (zh) 1982-10-29

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Legal Events

Date Code Title Description
AS Assignment

Owner name: CATERPILLAR INC., 100 N.E. ADAMS STREET, PEORIA, I

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:CATERPILLAR TRACTOR CO., A CORP. OF CALIF.;REEL/FRAME:004669/0905

Effective date: 19860515

Owner name: CATERPILLAR INC., A CORP. OF DE.,ILLINOIS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:CATERPILLAR TRACTOR CO., A CORP. OF CALIF.;REEL/FRAME:004669/0905

Effective date: 19860515