Another Passage Controlled By Motive Fluid Pressure Or Flow Responsive Valve (468) Patents (Class 91/451)
  • Patent number: 10087599
    Abstract: A shovel that performs excavation in accordance with a complex excavation operation including an arm or bucket closing operation and a boom raising operation includes an excavation operation detection part, a position detection part, a maximum allowable pressure calculation part, and a boom cylinder pressure control part. The excavation operation detection part detects that the complex excavation operation has been performed. The position detection part detects the position of the shovel. The maximum allowable pressure calculation part calculates the pressure of the contraction-side oil chamber of a boom cylinder corresponding to an excavation reaction force at a time when the shovel is lifted by the excavation reaction force as a maximum allowable pressure, based on the position of the shovel. The boom cylinder pressure control part controls the pressure of the contraction-side oil chamber not to exceed the maximum allowable pressure when the complex excavation operation is performed.
    Type: Grant
    Filed: December 9, 2016
    Date of Patent: October 2, 2018
    Assignee: SUMITOMO(S.H.I.) CONSTRUCTION MACHINERY CO., LTD.
    Inventor: Hiroyuki Tsukamoto
  • Patent number: 9957982
    Abstract: An electromagnetic switching valve, for which the maximum opening is set to be small, is disposed on piping between a lift cylinder and a hydraulic pump motor. A pilot check valve, for which the maximum opening is set to be larger than the electromagnetic switching valve, is disposed on piping, different from the piping, between the lift cylinder and the hydraulic pump motor. In addition, during lowering operations, first, the electromagnetic switching valve is opened, and then after the same is opened, the pilot check valve is opened after a prescribed time has passed. Thus, the shock generated when lowering an object to be raised/lowered is reduced and a fork is operated quickly.
    Type: Grant
    Filed: October 18, 2012
    Date of Patent: May 1, 2018
    Assignee: KABUSHIKI KAISHA TOYOTA JIDOSHOKKI
    Inventors: Yuki Ueda, Tsutomu Matsuo, Hirohiko Ishikawa
  • Patent number: 9695802
    Abstract: A wind turbine blade assembly comprises a rotatable hub, a blade secured to the hub, and a pitch system. The pitch system is disposed to rotate the blade with respect to the hub about a pitch axis not extending through an aerodynamic centroid of the blade. The pitch system comprises a hydraulic cylinder pitch actuator and a relief valve. The hydraulic cylinder pitch actuator has first and second pressure chambers. The relief valve is configured to aerodynamically unload the blade by equilibrating the first and second pressure chambers in response to a pressure differential between the first and second pressure chambers exceeding a critical threshold corresponding to a pre-strain blade twist.
    Type: Grant
    Filed: March 1, 2013
    Date of Patent: July 4, 2017
    Assignee: United Technologies Corporation
    Inventor: Robert H. Perkinson
  • Patent number: 9518370
    Abstract: A shovel that performs excavation in accordance with a complex excavation operation including an arm or bucket closing operation and a boom raising operation includes an excavation operation detection part, a position detection part, a maximum allowable pressure calculation part, and a boom cylinder pressure control part. The excavation operation detection part detects that the complex excavation operation has been performed. The position detection part detects the position of the shovel. The maximum allowable pressure calculation part calculates the pressure of the contraction-side oil chamber of a boom cylinder corresponding to an excavation reaction force at a time when the shovel is lifted by the excavation reaction force as a maximum allowable pressure, based on the position of the shovel. The boom cylinder pressure control part controls the pressure of the contraction-side oil chamber not to exceed the maximum allowable pressure when the complex excavation operation is performed.
    Type: Grant
    Filed: June 17, 2015
    Date of Patent: December 13, 2016
    Assignee: SUMITOMO(S.H.I.) CONSTRUCTION MACHINERY CO., LTD.
    Inventor: Hiroyuki Tsukamoto
  • Patent number: 9261113
    Abstract: A pressurized fluid subassembly comprising: (a) a fluid driven actuator configured to utilize fluid at a high pressure to change an overall length of the fluid driven actuator; and, (b) a sequence valve interposing a low pressure line and a supply line conveying the fluid to the fluid driven actuator, the sequence valve including a first sequence configured to inhibit fluid communication between the supply line and the low pressure line when the fluid at the high pressure is actively supplied to the fluid driven actuator, the sequence valve including a second sequence configured to establish fluid communication between the supply line and the low pressure line when the fluid at the high pressure is not actively supplied to the fluid driven actuator, wherein the sequence valve includes a variable bias that changes depending upon whether the fluid at the high pressure is actively supplied to the fluid driven actuator.
    Type: Grant
    Filed: August 22, 2012
    Date of Patent: February 16, 2016
    Assignee: DEERE + COMPANY
    Inventors: Matthew J. Ramler, Calin Raszga
  • Patent number: 9181964
    Abstract: A hydraulic system and method of controlling hydraulic pressure are disclosed. The hydraulic system includes a pump fluidly coupled to a reservoir that contains hydraulic fluid, a control valve fluidly coupled to the pump, the control valve being selectively movable between at least two positions, a relief valve fluidly coupled to the pump via a relief conduit, the relief valve operable to flow hydraulic fluid from an outlet of the pump to the reservoir, and a variable pressure setpoint module fluidly coupled to the relief valve and the control valve. The variable pressure setpoint module being operable to open the relief valve in response to at least two pressure setpoints depending on a position of the control valve.
    Type: Grant
    Filed: April 16, 2013
    Date of Patent: November 10, 2015
    Assignee: Caterpillar Inc.
    Inventor: Andew J. Kleitsch
  • Patent number: 8899143
    Abstract: A hydraulic control system is disclosed. The hydraulic control system may have a pump configured to pressurize a fluid, an actuator, a position sensor associated with the actuator and configured to generate a first signal indicative of a position of the actuator, and a circuit fluidly connecting the pump to the actuator. The hydraulic control system may also have a valve associated with the circuit and configured to move from a first position, at which fluid relief from the circuit is inhibited, toward a second position, at which fluid is relieved from the circuit through the valve, when a pressure of fluid within the circuit exceeds a threshold setting of the valve. The hydraulic control system may additionally have a controller in communication with the position sensor and the valve. The controller may be configured to selectively cause adjust the threshold setting of the valve based on the first signal.
    Type: Grant
    Filed: June 28, 2011
    Date of Patent: December 2, 2014
    Assignee: Caterpillar Inc.
    Inventors: Aaron Y. Ho, Bryan A. Johnson, Nikhil Jalgaonkar
  • Patent number: 8573111
    Abstract: A load sense connection is provided between the implement rockshaft cylinders and the load-sensed power source. However, to avoid tractor starting difficulty, a valve structure is provided in the power beyond fluid line to keep the fluid line closed when starting the tractor. This valve structure provides a hydraulic latching function that allows the load-sensed power source to be activated and deactivated depending on the SCV function. The load-sensed power source is activated when the rockshaft cylinder(s) is fully extended and remains activated or latched when the SCV is returned to neutral. The load-sensed power source is deactivated or unlatched when the rockshaft cylinder is retracted.
    Type: Grant
    Filed: April 19, 2010
    Date of Patent: November 5, 2013
    Assignee: Deere & Company
    Inventors: William Douglas Graham, Aaron L. Barfels
  • Patent number: 8020485
    Abstract: Disclosed is a lifting gear valve arrangement for controlling a double-action lifting gear or an add-on unit with a continuously adjustable directional control valve and with an individual pressure compensator via which a pressure medium volume flow to and from a lifting cylinder of the lifting gear can be controlled. A proportionally adjustable pressure limiting valve is provided in the pressure medium flow path between an outlet connection of the directional control valve and a working connection of the lifting gear valve arrangement, via which the pressure inside this area can be limited to a maximum value. The adjustment of the pressure limiting valve is preferably performed as a function of the operating states of the lifting gear or of the type of add-on unit.
    Type: Grant
    Filed: July 6, 2005
    Date of Patent: September 20, 2011
    Assignee: Bosch Rexroth AG
    Inventors: Soenke Jessen, Gerhard Keuper, Heinrich Loedige, Reiner Kunz
  • Patent number: 7921689
    Abstract: An improved method and apparatus are provided for constructing and operating a linear actuator, and equipment incorporating a linear actuator, by operatively connecting a pressure biasing pneumatic arrangement between the driving member and the driven member of a mechanical linear actuator for applying a unidirectional biasing force between the driving and driven members, along an axis of motion, regardless of the location or movement of the driving and driven elements with respect to one another along the axis of motion. The pneumatic biasing arrangement is also configured, connected and operated to reduce the force which must be exerted by the driving and driven members in extending and retracting the linear actuator. The pneumatic biasing arrangement may further be configured for preferentially aiding extension or retraction of the actuator.
    Type: Grant
    Filed: July 2, 2010
    Date of Patent: April 12, 2011
    Assignee: Unico, Inc.
    Inventors: Robb G. Anderson, James P. McCrickard, Thomas L. Beck
  • Patent number: 7849687
    Abstract: A solar panel carrier T is provided at a sub-structure U such that it can be rotated and tilted by means of hydrostatic rotation and tilt motors M, M?. In an electrohydraulic adjusting device for the solar panel carrier T a motor pump aggregate 8 is connected to the hydrostatic motors. Within working lines A, B of the tilt hydrostatic motor M at least one tilt control system K is provided, which comprises valve components and a pilot pressure circuit. The tilt control system K comprises pressure actuated blocking valves or load holding valves LHVA, LHVB. For automatically adjusting a protected position S of the carrier T a suction line N is provided at the side of the hydrostatic tilt motor facing to the blocking valves or load holding valves. The suction line N is surveyed by a monitoring solenoid 18 and is opened depending on initial pressure conditions in case of switching off the electric power and/or in case of an electric breakdown.
    Type: Grant
    Filed: March 19, 2008
    Date of Patent: December 14, 2010
    Assignee: HAWE Hydraulik GmbH & Co. KG
    Inventors: Martin Heusser, Hilarius Hundschell
  • Patent number: 7748308
    Abstract: An improved method and apparatus are provided for constructing and operating a linear actuator, and equipment incorporating a linear actuator, by operatively connecting a pressure biasing pneumatic arrangement between the driving member and the driven member of a mechanical linear actuator for applying a unidirectional biasing force between the driving and driven members, along an axis of motion, regardless of the location or movement of the driving and driven elements with respect to one another along the axis of motion. The pneumatic biasing arrangement is also configured, connected and operated to reduce the force which must be exerted by the driving and driven members in extending and retracting the linear actuator. The pneumatic biasing arrangement may further be configured for preferentially aiding extension or retraction of the actuator.
    Type: Grant
    Filed: September 25, 2006
    Date of Patent: July 6, 2010
    Assignee: Unico, Inc.
    Inventors: Robb G. Anderson, James P. McCrickard, Thomas L. Beck
  • Patent number: 7104181
    Abstract: A hydraulic control circuit for a hydraulic cylinder is described for the raising and lowering of a boom on a telescopic loader. First and second chambers of the hydraulic cylinder are connected to a control valve over first and second supply lines and are selectively connected to either a hydraulic pressure source or to a hydraulic reservoir. The circuit includes on-off valves for controlling the flow through a first hydraulic line extending between the first chamber of the cylinder and the hydraulic reservoir, and through a second hydraulic line extending between the second chamber and the hydraulic reservoir in such a way that a floating position can be provided. Furthermore, a load-holding valve arrangement is provided in the first supply line at a location between the control valve and the first chamber of the cylinder.
    Type: Grant
    Filed: February 18, 2004
    Date of Patent: September 12, 2006
    Assignee: Deere & Company
    Inventors: Marcus Bitter, David Price, Steffen Schlemmer, Marlin Onnen
  • Patent number: 6955115
    Abstract: A fluid system is provided wherein two different fluid circuits are connected in parallel with a single source of pressurized fluid and the two fluid circuits can function together even when one of the loads is lighter than the other. This is accomplished by having the lightly loaded circuit having a directional control that when operated in one of its operative positions the flow from the rod end of the cylinder is directed through the directional control valve and combined with the supply flow being directed to the head end of the cylinder. With the other heavier loaded circuit also being actuated, the pressure of the fluid from the rod end of the fluid cylinder is equalized with the pressure of the heavier loaded circuit. Consequently, the speed of the heavier loaded circuit does not stall or slow down relative to the lightly loaded circuit.
    Type: Grant
    Filed: December 15, 1999
    Date of Patent: October 18, 2005
    Assignee: Caterpillar Inc.
    Inventors: Michael A. A'Hearn, Thomas J. Hajek, Sr., Larry W. Lorimor, Daniel T. Mather, Srikrishnan T. Tolappa
  • Patent number: 6922923
    Abstract: In an excavating/slewing work truck, the boom falls freely at the time of lowering operation without requiring any power but the flow rate of a pump increases excessively when the speed is balanced with other acutuators and power loss is inevitable for enhancing the operability. In order to eliminate this inconvenience, a first oil path (41) connecting a bottom side cylinder port (CB) and a tank port (T2), a second oil path (42) connecting a pump port (P2) and a rod side cylinder port (CR), and a third oil path (43) connecting a pump port (P1) and a tank port (T1) are provided, respectively, with first, second and third restrictors (61), (62) and (63) at the boom down position of a change-over valve (51) for the boom cylinder of an excavating/slewing work truck, wherein the first restrictor (61) restricts by such an amount as the work machine lowers gravitationally an the second restrictor (62) restricts by such an amount as the pressure on the boom side is not exceeded.
    Type: Grant
    Filed: November 29, 2001
    Date of Patent: August 2, 2005
    Assignee: Yanmar Co., Ltd.
    Inventor: Masami Kondou
  • Patent number: 6848473
    Abstract: An insert or cartridge that fits into a cavity in a valve body provides a check valve function and an anti-cavitation function and a pressure relief function. This insert is substantially circular and has an internal cavity with a valve assembly that has two pairs of valve seats, one pair of valve seats providing the anti-cavitation function and the other pair of valve seats providing the pressure relief function. The outside of the insert itself engages with a sealing surface in the cavity in the valve body to provide the check valve function.
    Type: Grant
    Filed: November 21, 2003
    Date of Patent: February 1, 2005
    Assignee: CNH America LLC
    Inventors: George T. Fiala, David W. Swaim
  • Patent number: 6805161
    Abstract: A hydraulic valve system (1) has a supply connection arrangement, having a high-pressure connection (P) and a low-pressure connection (T), a working connection arrangement, having two working connections (A, B), which can be connected with a hydraulic motor (2), and a directional valve (4) between the supply connection arrangement (P, T) and the working connection arrangement (A, B), which is connected with the working connection arrangement (A, B) via working lines (17, 18), in which are arranged check valves (21, 22), which can be opened by means of pressure.
    Type: Grant
    Filed: April 24, 2003
    Date of Patent: October 19, 2004
    Assignee: Sauer-Danfoss ApS
    Inventors: Siegfried Zenker, Thorkild Christensen
  • Patent number: 6722257
    Abstract: At a step of pressurizing a workpiece after reducing a speed of a piston rod at an end of a forward stroke of the piston rod by restrictively allowing compressed air to flow out of an exhaust-side pressure chamber, operation of a rapid exhaust valve is triggered by reduction of internal pressure of the exhaust-side pressure chamber to lower pressure than internal pressure of a pressurizing-side pressure chamber to thereby directly open the exhaust-side pressure chamber into the atmosphere through the rapid exhaust valve and rapidly reduce back pressure of a main piston remaining in the exhaust-side pressure chamber.
    Type: Grant
    Filed: January 4, 2002
    Date of Patent: April 20, 2004
    Assignee: SMC Corporation
    Inventors: Seikai Yoh, Kouichiro Ishibashi, Hitoshi Yamamoto, Nobuhiro Fujiwara
  • Patent number: 6699311
    Abstract: A fluid circuit for raising and lowering an implement including a quick drop valve member movable between at least a first position and a second position, the first position corresponding to a non-quick drop hydraulic fluid flow path of the fluid circuit and the second position corresponding to a quick drop hydraulic fluid flow path of the fluid circuit, the quick drop valve member being movable between at least the first and second positions based on pressures in the fluid circuit produced by hydraulic fluid. The fluid circuit further including a control system configured to selectively apply a biasing force against the quick drop valve member biasing the quick drop valve in the first position, the control system providing the biasing force independent of pressures in the fluid circuit produced by the hydraulic fluid.
    Type: Grant
    Filed: December 28, 2001
    Date of Patent: March 2, 2004
    Assignee: Caterpillar Inc
    Inventors: David P. Smith, Rudy V. Mills, Robert A. Aarestad, Chad T. Brickner
  • Patent number: 6694859
    Abstract: A single stage, electrically controlled variable pressure relief valve assembly is provided that uses a valving element assembly slideably disposed within a housing having first and second inlet and outlet ports, the valving element assembly has a differential area defined thereon which acts in cooperation with an electrically controlled coil assembly to proportionally control the flow of fluid between the inlet port and an outlet ports of the housing. The valving element assembly has inlet and outlet ports that are oriented generally perpendicular to the flow of the fluid through the valving element assembly to effectively offset the effects of flow forces acting on the valving element.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: February 24, 2004
    Assignee: Caterpillar Inc
    Inventor: David P. Smith
  • Patent number: 6581639
    Abstract: An insert or cartridge that fits into a cavity in a valve body provides a check valve function and an anti-cavitation function and a pressure relief function. This insert is substantially circular and has an internal cavity with a valve assembly that has two pairs of valve seats, one pair of valve seats providing the anti-cavitation function and the other pair of valve seats providing the pressure relief function. The outside of the insert itself engages with a sealing surface in the cavity in the valve body to provide the check valve function.
    Type: Grant
    Filed: October 17, 2001
    Date of Patent: June 24, 2003
    Assignee: Case Corporation
    Inventors: George T. Fiala, David W. Swaim
  • Patent number: 6431049
    Abstract: A double acting actuator is used for operating a pair of latches, and is controlled through a manifold that will permit a base end of the actuator to remain under pressure, and accommodate valve and piston leakage by connecting the rod end of the actuator to drain through a small orifice. The manifold additionally has relief valves for providing different pressures for the rod and base ends of the actuator, and a flow divider that provides a low flow to the actuator while the main flow from a pump is used for other hydraulic components.
    Type: Grant
    Filed: August 24, 2000
    Date of Patent: August 13, 2002
    Assignees: Jem Technical Marketing Co., Inc., Clark Equipment Company
    Inventors: Gerald M. Berg, Thomas M. Sagaser, Gaylen E. Halstensgaard, Harold K. Beckstrom, Michael J. Stoltenow, Timothy P. Sperry
  • Patent number: 6405633
    Abstract: The present invention is concerned with a work machine having a telescopic arm coupled to the front thereof. This arm is used for seating various sorts of frontal attachments and is raised and lowered by means of a hydraulic piston-cylinder unit. Now in order to ensure that an installed frontal attachment always rests on the ground with a pre-selected force, use is made of a pilot controlled seat valve and an adjustable pressure regulating valve which ensure that a constant pressure is maintained in the cylinder chamber formed below the base of the piston in the piston-cylinder unit when a constant supply of oil is fed to this part of the cylinder chamber. In consequence, this means that the installed frontal attachment always rests on the ground with one and the same force independently of whether the ground is flat or uneven. The frontal attachment thus precisely copies the contour of the ground at all times.
    Type: Grant
    Filed: February 7, 2001
    Date of Patent: June 18, 2002
    Assignee: Caterpillar S.A.R.L.
    Inventors: Heinrich Dueckinghaus, Dirk Schlichting
  • 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
  • Patent number: 6116139
    Abstract: A combination drive and method for applying power through a piston rod (A) operated by an air cylinder (B) is controlled by an elongated self-locking threaded drive member (C) rotated by an electric motor (D) for affording positioning and velocity control for the air operated cylinder and the guided piston rod which stops and is positively positioned upon cessation of operation of the electric motor. Control apparatus includes a valve housing (35) positioning a spool (40) fixed on one end to the elongated threaded drive member (C), and an assembly (45) for moving the spool axially in respect to the electric motor (D) through an axially compliant coupling (50) so that by controlling the motor the valve is thereby controlled.
    Type: Grant
    Filed: August 13, 1996
    Date of Patent: September 12, 2000
    Assignee: Compact Air Products, Inc.
    Inventors: Lawrence F. Yuda, Jr., Prasad Balakrishnan, Edward Camp Tibbals, Jr.
  • Patent number: 6068064
    Abstract: Agricultural implement to be conveyed by a self propelled vehicle includes a structural frame and a substructure moveable between a raised position and a lowered position. The substructure has at least one ground engaging tool supported thereon so as to engage the ground when the substructure is moved to the lowered position. A fluid circuit is provided to control engagement of the tool with the ground. The fluid circuit includes a first check valve having a first side connectable to a source of pressurized fluid flow and a second side connected to a fluid cylinder. The fluid cylinder is operated between a retracted position and an extended position to move the substructure between the raised position and the lowered position, respectively. A second check valve is provided having a first side connected to drain and a second side connected to the fluid cylinder. A sensor assembly opens the second check valve when pressurized fluid flow is received by the first side of the first check valve.
    Type: Grant
    Filed: May 20, 1998
    Date of Patent: May 30, 2000
    Assignee: Case Corporation
    Inventors: Leonard A. Bettin, Daniel J. Boos, Ronald M. Weber
  • Patent number: 6050089
    Abstract: A remotely located brake booster for supplying an input force to a pressurizing device to develop pressurized fluid to effect a brake application. The brake booster responds to an actuation signal in the form of pressurized fluid being communicated from a control apparatus activated by an operator. The brake booster has a housing with a bore and a piston located therein to define an operational chamber. The housing has an inlet port through which pressurized fluid from the control apparatus is receiving by the operational chamber. The piston moves from a rest position to an actuation position in response to pressurized fluid being received in the operational chamber to produce the input force for operating the pressurizing device.
    Type: Grant
    Filed: July 24, 1998
    Date of Patent: April 18, 2000
    Assignee: Robert Bosch Corporation
    Inventors: Kenneth Scott Towers, Raymond Kosarski, Jr.
  • Patent number: 5992721
    Abstract: A rodless cylinder rope tensioning apparatus maintains tension in an endless rope system operable for threading a web in a paper-making apparatus and includes at least one rodless cylinder having at least one yoke sheave attached to the internal piston in the rodless cylinder. A rope is stretched around an entry guide roller and the yoke sheave and is stretched by operation of the rodless cylinder, which selectively causes the piston to relocate the yoke sheave along the length of the rodless cylinder and apply a selected degree of tension to the rope. In a preferred embodiment a pair of entry guide rollers is provided in a frame containing a pair of parallel rodless cylinders, each having a yoke sheave independently movable along the respective rodless cylinder by operation of the corresponding rodless cylinder piston, to effect tensioning of a pair of ropes in the paper-making apparatus.
    Type: Grant
    Filed: January 2, 1998
    Date of Patent: November 30, 1999
    Assignee: MEC Enterprises, Inc.
    Inventors: Michael E. Craft, Douglas M. Craft, Paul E. Mayfield
  • Patent number: 5855159
    Abstract: A hydraulic circuit for a boom cylinder in a hydraulic shovel has a pressurized discharge fluid from a hydraulic pump that is driven by an engine, the pressurized discharge fluid supplied via a directional control valve for a boom into a retraction pressure chamber and an extension pressure chamber of a boom cylinder for swinging the boom upwards and downwards. A relief valve is included in a circuit for connecting the retraction pressure chamber of the boom cylinder to the boom directional control valve, the relief valve having a relief set pressure. A switching device is included for switching the relief set pressure to a low pressure as well as to a high pressure if the directional control valve is set at a position that is other than a neutral position thereof, when the engine is driven, the switching device being adapted to switch the relief set pressure to a high pressure when the engine is halted.
    Type: Grant
    Filed: February 18, 1997
    Date of Patent: January 5, 1999
    Assignee: Komatsu Ltd.
    Inventors: Nobumi Yoshida, Nobuhisa Honda
  • Patent number: 5813310
    Abstract: A working machine fall preventive valve apparatus is constructed with a cylinder side passage, a valve body, a check valve, a flow rate control valve, and a safety valve. The cylinder side passage is adapted to communicate with a cylinder port which is open to a cylinder side mounting surface. The valve body has a directional control valve side passage which is adapted to communicate with a directional control valve port. The check valve is provided in the valve body and prevents a pressure fluid from flowing into the directional control valve side passage from the cylinder side passage. The flow rate control valve provided in the valve body normally blocks communication between the directional control valve side passage and the cylinder side passage is responsive to an external signal for establishing the above mentioned communication. The safety valve is provided in the valve body and relieves a high pressure in the cylinder side passage.
    Type: Grant
    Filed: February 4, 1997
    Date of Patent: September 29, 1998
    Assignee: Komatsu, Ltd.
    Inventors: Shuji Hori, Tadao Karakama
  • Patent number: 5806402
    Abstract: In a linear actuator, a cylinder is separated into forward and reverse chambers by a piston. A lead screw is threadedly engaged in the piston and a piston rod connects to the load. A turbine applies torque to the screw to urge the screw toward clockwise or counterclockwise rotation depending on the direction of the piston movement. The tangent of the lead screw helix angle is so substantially equal to the coefficient of friction between the piston and the screw that the torque generated by the turbine does not significantly vary the force exerted on the load and the force on the load does not significantly vary the speed of movement of the load. Variations between the static and dynamic coefficients of friction between the lead screw and the piston can be offset by selection of an appropriate lead angle and friction coefficient in the turbine driven system.
    Type: Grant
    Filed: November 22, 1996
    Date of Patent: September 15, 1998
    Inventor: Michael F. Henry
  • Patent number: 5752426
    Abstract: A pilot pressure operated directional control valve is provided in which a housing is formed therein with a spool having a plurality of ports. The spool bore has a spool fittingly inserted therein so as to be slidably displaceable therein and the spool is slidably displaced both by a spring and under a pilot pressure led into a pressure receiving chamber. Also a spring box is attached to an end surface of the housing in a longitudinal direction of the spool. The spring box is provided with a hollow portion which contains the spring while forming a pressure receiving chamber, as well as a pilot pressure fluid inlet that communicates with the hollow portion and is open in the longitudinal direction of the spool.
    Type: Grant
    Filed: September 27, 1996
    Date of Patent: May 19, 1998
    Assignee: Komatsu Ltd.
    Inventors: Kazunori Ikei, Keisuke Taka
  • Patent number: 5735305
    Abstract: An unloading system including an unload valve draining a part of supplied pressurized fluid to a tank and a switching valve for draining a pressurized fluid for biasing the unload valve in a direction for reducing a flow rate of the fluid supplied to the tank. The unload valve and the switching valve are arranged in series in axial direction in a valve main body.
    Type: Grant
    Filed: June 11, 1996
    Date of Patent: April 7, 1998
    Assignee: Komatsu Ltd.
    Inventors: Kazunori Ikei, Keisuke Taka
  • Patent number: 5664477
    Abstract: A control system is provided for use in a hydraulic system to provide a simple arrangement with a limited number of elements that bypasses the system flow in the event of an electrical malfunction in the system and further allows other hydraulic circuits to operate even if one or more of the hydraulic circuits have experienced an electrical malfunction. The subject arrangement uses an electro-hydraulic fluid flow control valve mechanism in conjunction with directional valve mechanisms that have at least three functional positions and are controlled by associated electrically controlled displacement control mechanisms in response to receipt of electrical signals from an electrical controller.
    Type: Grant
    Filed: May 10, 1996
    Date of Patent: September 9, 1997
    Assignee: Caterpillar Inc.
    Inventor: Douglas W. Koehler
  • Patent number: 5644915
    Abstract: A control system for controlling the movement of the ram of a press or press brake of the type having one or two main cylinders with pistons operatively attach to the ram. The control system comprises a programmable processor with inputs from a pressure transducer indicating the pressure applied to the one or two pistons and a linear potentiometer for each side of the ram to indicate ram position and levelness. The control system further includes a hydraulic circuit operated by outputs from the processor. The hydraulic circuit comprises a variable volume load sense-controlled pump supplying hydraulic fluid through a speed control assembly to a solenoid-actuated directional valve determining upward and downward movement of the ram. The speed control assembly comprises at least two lines connected to the output line of the pump and to the speed control assembly output line to the directional valve. At least one of the at least two speed control assembly lines is provided with a restricting orifice.
    Type: Grant
    Filed: April 25, 1996
    Date of Patent: July 8, 1997
    Assignee: Cincinnati, Incorporated
    Inventors: Paul A. Dressing, Dean M. Valvano
  • Patent number: 5577433
    Abstract: In a linear actuator, a cylinder is separated into forward and reverse chambers by a piston. A lead screw is threadedly engaged in the piston and a piston rod connects to the load. A turbine applies torque to the screw to urge the screw toward clockwise or counterclockwise rotation depending on the direction of the piston movement. The tangent of the lead screw helix angle is so substantially equal to the coefficient of friction between the piston and the screw that the torque generated by the turbine does not significantly vary the force exerted on the load and the force on the load does not significantly vary the speed of movement of the load. Variations between the static and dynamic coefficients of friction between the lead screw and the piston can be offset by selection of an appropriate lead angle and friction coefficient in the turbine driven system.
    Type: Grant
    Filed: September 6, 1995
    Date of Patent: November 26, 1996
    Inventor: Michael F. Henry
  • Patent number: 5515879
    Abstract: A pressure control valve having a housing with a main inlet passage and a bypass outlet passage. A combined control is located in the housing to control the flow of fluid from the main inlet passage to the bypass outlet passage. The combined control includes a chamber in the housing having an inlet connected to the main inlet passage, an outlet connected to the bypass outlet opening and a loading opening. A poppet is located in the chamber and is movable between a first position closing the inlet and a second position opening the inlet to allow fluid to flow from the main inlet passage to the bypass outlet passage. A spool is positioned within the poppet and is movable between an open position allowing fluid to flow between the main inlet passage and the bypass outlet passage. A spring biases the spool toward the closed position. A connecting passage is located in the housing to connect the main inlet passage to the loading opening.
    Type: Grant
    Filed: November 28, 1994
    Date of Patent: May 14, 1996
    Inventor: James R. Mollo
  • Patent number: 5440967
    Abstract: A method for controlling a hydraulic motor with a hydraulic valve comprising an inlet section which includes a pump and tank connection and a maneuvering section having a slide (B1) and a load signal system (L1, L2, L3). The hydraulic valve also includes two regulating constrictions (S3, S4) which can be connected to and from a motor (C), such as a hydraulic piston-cylinder device. The maneuvering slide (B1) also includes a load level detecting constriction (S2) and a load signal drain (S5), and the pump generates an idling pressure. When maneuvering the maneuver slide (B1), the load signal Ps of the load signal system is increased by a further constriction (S1) located between the pump connection and that side of the load detecting constriction (S2) that has the higher pressure during the maneuvering process.
    Type: Grant
    Filed: January 7, 1994
    Date of Patent: August 15, 1995
    Assignee: Voac Hydraulics Boras AB
    Inventor: Orjan Wennerbo
  • Patent number: 5423243
    Abstract: A relief valve 23 serving as cushion pressure adjusting means in a cushion mechanism is provided on a support member 4, and the support member 4 is rotatably mounted on covers 2 and 3 of a pneumatic cylinder in order to facilitate adjustment of relief pressure.
    Type: Grant
    Filed: August 16, 1994
    Date of Patent: June 13, 1995
    Assignee: SMC Corporation
    Inventors: Yoshisuke Yamashita, Kunihisa Kaneko, Nobuhiro Fujiwara
  • Patent number: 5419236
    Abstract: In a method and a configuration for operating a hydraulic drive, a 3/2-port directional seat valve, which is driven by solenoid coils, controls an application of high-pressure fluid through a working piston of a piston/cylinder system. In order to increase the circuit-breaking capacity of the working piston, a hydraulic booster valve which is driven hydraulically by the 3/2-port directional seat valve is used for clearing a direct path from the piston/cylinder system to the low-pressure reservoir during switching-off.
    Type: Grant
    Filed: August 20, 1993
    Date of Patent: May 30, 1995
    Assignee: ABB Patent GmbH
    Inventor: Horst Plettner
  • Patent number: 5394903
    Abstract: The present invention relates to a hydraulic control valve in a construction machine, wherein a parallel port (20b) and bridge ports (20c) which are provided in a valve body (40) of the hydraulic control valve are formed by machining, cylinder drain ports (20e) are limited to through holes opened on opposite sides of the valve body (40) and caused to join together in a tank port block (39). Accordingly, when the valve body (40) is manufactured by casting, only a main core (19) forming a spool port (13h) need be used, so that the control valve can be made compact in size. Furthermore, portions (20', 21') where a passage of a neutral port of the core has heretofore been formed by jointing the main core (19) to joint cores (20, 21) are formed by machining a manual operation process of jointing can be dispensed with and the working efficiency and casting accuracy are improved.
    Type: Grant
    Filed: December 14, 1993
    Date of Patent: March 7, 1995
    Assignee: Komatsu Zenoah Kabushiki Kaisha
    Inventor: Hiroyoshi Tominaga
  • Patent number: 5368061
    Abstract: A load sensed variable output gear pump having adjustable high pressure compensation, tuneable response, low unloading pressure and variable pressure drop adjustability. It comprises a unitary housing enclosing a pump which pumps through a main inlet-outlet passage which bypasses through a combined control having a single load sense line. The single control including a chamber connected to the load line by means of a popper with a 2:1 area ratio and a spool having a 1:1 area ratio. An overload control may also be used connected to an inlet load sensing passage which tends to close said fixed and variable controls.
    Type: Grant
    Filed: September 13, 1993
    Date of Patent: November 29, 1994
    Inventor: James R. Mollo
  • Patent number: 5337778
    Abstract: A pressure control valve of the type having pump, tank and load-sensing connections used in conjunction with one or more proportional type valves. In this type of system a load-sensing signal is tapped off from the output side of the proportional valves and conveyed to the load-sensing connection of the pressure control valve. A pressure control valve of the type herein has load-sensing and pressure chambers at opposite ends thereof with a slide valve therebetween which is spring biased towards the pressure chamber and controls the internal flow from the pump connection to the tank connection. The slide valve has an auxiliary change-over type valve which selectively connects the pressure chamber to the pump and load-sensing connections in response to a pressure differential between the pump and load-sensing connections to achieve a pressure balance between the load-sensing chamber and the pressure chamber.
    Type: Grant
    Filed: March 30, 1993
    Date of Patent: August 16, 1994
    Assignee: Danfoss A/S
    Inventors: Svend E. Thomsen, Thorkild Christensen, Siegfried Zenker
  • Patent number: 5335495
    Abstract: Described herein is a brake valve which is arranged to prevent low pressure relief actions by relief valves (59A) and (59B) at the time of starting an actuator, for improving the response characteristics and the safety of operation. This brake valve has relief valves (59A) and (59B) and check valves (70A) and (70B) located in coaxial positions, the check valves (70A) and (70B) being arranged to seat on fore end portions of valve seat members (62A) and (62B) when opened, thereby to substantially block the communication of the valve seat members (62A) and (62B) with inlet link passages (56A) and (56B). Therefore, when the check valve (70A) or (70B) is opened at the time of starting the actuator, the valve seat member (62A) or (62B) is supplied with only a throttled flow of hydraulic pressure through the notched portions (73A) or (73B).
    Type: Grant
    Filed: May 13, 1993
    Date of Patent: August 9, 1994
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hitoshi Sato, Yukio Kanno
  • Patent number: 5313873
    Abstract: A fluid unit, for example a piston/cylinder unit, is supplied with fluid via a cyclically opened or closed on/off valve. The vacuum peaks occurring on the outlet side of the on/off valve when it is closed and the inertia forces of the flowing fluid are used to supply additional fluid to the fluid unit via a non-return valve leading from a low-pressure connection or reservoir to the fluid unit.
    Type: Grant
    Filed: October 9, 1992
    Date of Patent: May 24, 1994
    Assignee: Mercedes-Benz AG
    Inventors: Heinz Gall, Kurt Senn
  • Patent number: 5218897
    Abstract: This invention provides a hydraulic circuit apparatus for operating a work-implement actuating cylinder arranged such that, during an earth compacting operation using a bucket, a work implement or boom is lowered by its own weight, and during other operations, a part of the fluid under pressure in a lifting chamber of the actuating cylinder is supplied together with pressurized fluid discharged by a pump into a lowering chamber to increase the retracting speed of a piston rod in the work-implement actuating cylinder. The apparatus comprises a spool slidably inserted in a valve bore formed in an operating valve body so that it may be moved between a first actuating position, where a second port connected to the lowering chamber is communicated with a second tank port and a first port connected to the lifting chamber is communicated with a first pump port; and a second actuating position, where the second port is communicated with a second pump port and the first port is communicated with a first tank port.
    Type: Grant
    Filed: February 22, 1991
    Date of Patent: June 15, 1993
    Assignee: Kabushiki Kaisha Komatsu Seisakusho
    Inventors: Kiyoshi Shirai, Terruo Akiyama, Shigeru Shinohara, Naoki Ishizaki, Takahide Takiguchi
  • Patent number: 5209261
    Abstract: A slide valve, having a pump port, a reservoir port and at least one consumer port is described, which comprises a slide which is spring-loaded into a first position and can be moved into a second position counter to the spring force by means of an adjusting assembly. At least one of the consumer ports is connected to the reservoir port in the first slide position and to the pump port in the second slide position. Arranged between the adjusting assembly and the slide is a seat-controlled safety valve which, in the closed position, shuts off the adjacent open end of a longitudinal duct formed in the slide which, on the one hand, is connected to the consumer port and, on the other hand, to the reservoir port via the opened safety valve when the slide is possibly blocked and not loaded by the adjusting assembly. The longitudinal duct is closed off at the other end by an additional pressure relief valve which limits the pressure in the longitudinal duct with the safety valve usually being closed.
    Type: Grant
    Filed: July 6, 1992
    Date of Patent: May 11, 1993
    Assignee: Mercedes-Benz AG
    Inventors: Aydogan Cakmaz, Jurgen Class
  • Patent number: 5144881
    Abstract: As a result of an appropriate displacement of the control member, a connection of a fluid unit can, for pressure relief, be connected to a line leading to a low-pressure reservoir or be isolated from this line and/or, for the exertion of pressure, connected to a connection of a pressure source. Should the control member jam and be incapable of following an appropriate actuating stroke of a servomotor into the pressure-relieving position, a safety relief valve is opened by means of the actuating stroke.
    Type: Grant
    Filed: November 19, 1990
    Date of Patent: September 8, 1992
    Assignee: Mercedes-Benz AG
    Inventor: Aydogan Cakmaz
  • Patent number: 5129229
    Abstract: A hydraulic drive system for a civil-engineering and construction machine, includes an unloading valve connected to a discharge line of a hydraulic pump for relieving a hydraulic fluid from the hydraulic pump to a tank when a differential pressure between a delivery pressure of the hydraulic pump and a load pressure of an actuator exceeds a first predetermined value, for controlling the differential pressure. The unloading valve has a spool, a first receiving chamber arranged adjacent to one end of the spool, and a second pressure receiving chamber arranged adjacent to the other end of the spool, the delivery pressure of the hydraulic pump being introduced into the first pressure receiving chamber and the load pressure of the hydraulic actuator being introduced into the second pressure receiving chamber.
    Type: Grant
    Filed: June 18, 1991
    Date of Patent: July 14, 1992
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Kazunori Nakamura, Hideaki Tanaka
  • Patent number: 5127313
    Abstract: A check valve (14) with a valve opening actuator function and a bypass opening/closing valve (17) are disposed in parallel in a pressure oil supply/discharge passage (3) connected in communication with a hydraulic actuation chamber (2). The opening/closing valve (17) is adapted to be held at a valve opened position (Y) against a residual pressure holding spring (19) when the pressure on the check valve inlet (14a) side is normal and to be changed over to a valve closed condition (X) by means of the spring (19) when the pressure has lowered to a predetermined value. The pressure oil supply/discharge passage (3) and a pressure discharge passage (7) are connected in communication with each other through a pressure compensation valve (12). The opening/closing valve (17) is composed of a piston valve member (38) resiliently biased against a bypass valve seat (40) by means of the spring (19).
    Type: Grant
    Filed: June 12, 1991
    Date of Patent: July 7, 1992
    Assignee: Kabushiki Kaisha Kosmek
    Inventor: Keitaro Yonezawa