Motive Fluid Control Valve Responsive To Pressure In Supply Line To Or Exhaust Line From Motor Which It Modifies Patents (Class 91/518)
  • Patent number: 8479636
    Abstract: A valve arrangement has an adjustable control valve (10) including a control slide (12) for actuating at least one consumer connection (A, B) and an LS control line. The differential pressure of two actuating pressures (xa, xb) serves for the actuation of the control slide (12). Since the actuating pressures (xa, xb) also actuate a logic valve, which in turn influences an additional valve, and/or actuates a pressure compensator connected upstream to the control valve (10), the difference of the two actuating pressures (xa, xb) initially displaces the control slide of the control valve. 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 compensator.
    Type: Grant
    Filed: January 18, 2008
    Date of Patent: July 9, 2013
    Assignee: Hydac Filtertechnik GmbH
    Inventor: Winfried Rüb
  • Patent number: 8365523
    Abstract: A hydraulic assembly for driving and controlling small hydraulic units, such as hydraulic cylinders of a brake and/or clutch of a forestry winch, is disclosed. The hydraulic assembly includes a means for establishing and also maintaining a pre-determined pressure of a hydraulic media. The hydraulic assembly is characterized by as low as possible hydraulic loss. Also, a quantity of hydraulic media required for a regular operation and maintaining the pressure within the hydraulic assembly is as low as possible.
    Type: Grant
    Filed: December 27, 2006
    Date of Patent: February 5, 2013
    Assignee: Tajfun Planina Proizvodnja Strojev, D.O.O.
    Inventor: Iztok Span
  • Patent number: 8307752
    Abstract: A hydraulic motor having pistons, some of which are in a working phase and some are in a non-working phase, whereby the pistons are adapted to rotate the piston hydraulic motor's shaft or casing. To the piston hydraulic motor there are at least two working pressure medium channels, whereby the piston hydraulic motor can be connected for full volume or partial volume. In full volume, all the pistons in the working phase can be brought into the working phase in the motor by a pump's working pressure, whereas in the case of partial volume flow only some pistons can be brought into the working phase by the working pressure. The piston hydraulic motor comprises an actuator, which can close one of the piston hydraulic motor's pressurized inlet channels when the pressure in the other pressure medium channel falls below a certain critical value.
    Type: Grant
    Filed: January 25, 2008
    Date of Patent: November 13, 2012
    Assignee: Sampo-Hydraulics Oy
    Inventor: Roni Ryyppö
  • Patent number: 8100145
    Abstract: An LIFD valve assembly has a pressure balance device a pressure balance slide of which is urged in the opening direction by a pressure downstream of a metering aperture and in the closing direction by a control pressure preferably corresponding to the highest load pressure of a plurality of consumers, and a load pressure downstream of the metering aperture is reportable to a line via the pressure balance device, and a load-maintaining device that can be put in a closing position, in which position a pressure medium flow path from a consumer to the metering aperture is blocked. The pressure balance slide is embodied in divided fashion, with an upper part and a lower part, wherein the latter is guided on the upper part, and determines the pressure balance device throttle cross section with a pressure balance control edge and embodies a closing body of the load-maintaining device.
    Type: Grant
    Filed: February 10, 2007
    Date of Patent: January 24, 2012
    Assignee: Robert Bosch GmbH
    Inventor: Matthieu Desbois-Renaudin
  • Patent number: 8055413
    Abstract: Faster shifting operation and reduced shift shock in response to a braking operation during a lift-foot-up shifting may be achieved when an automatic transmission is controlled by a method for compensating a hydraulic pressure that includes: determining whether a lift-foot-up shifting of the automatic transmission is under control; calculating a vehicle speed of a vehicle; calculating a deceleration rate of the vehicle; calculating a compensation hydraulic pressure to be applied to a friction member of the transmission, based on the deceleration rate; calculating a on-coming pressure based on the calculated compensation hydraulic pressure; and applying the calculated on-coming pressure to the friction member.
    Type: Grant
    Filed: December 7, 2007
    Date of Patent: November 8, 2011
    Assignees: Hyundai Motor Company, Kia Motors Corporation
    Inventor: Byeong Wook Jeon
  • Patent number: 7765915
    Abstract: A vehicular hydraulic system having a hydraulic pump and first and second hydraulic applications arranged in series. A dual relief valve defines first and second flow channels, a passageway and a bypass port. The first flow channel is disposed between the hydraulic pump and the first hydraulic application and the second flow channel is disposed between the first hydraulic application and the second hydraulic application. A first valve member controls fluid flow through the passageway and allows fluid flow from the first to the second flow channel through the passageway when fluid pressure within the first flow channel exceeds a first threshold pressure. A second valve member controls fluid flow through the bypass port and allows fluid flow from the second flow channel to a return line through the bypass port when fluid pressure within the second flow channel exceeds a second threshold pressure.
    Type: Grant
    Filed: September 19, 2007
    Date of Patent: August 3, 2010
    Assignee: GM Global Technology Operations, Inc.
    Inventors: James L. Davison, Kenneth P. Webber, Rick L. Lincoln, Albert C. Wong
  • Patent number: 7581487
    Abstract: A pressure-compensating directional control valve, for actuating hydraulic actuators, comprising at least one modular valve body, with one through receptacle for a slidable shuttle, a driving fluid delivery port connected to a pump, a discharge fluid port, a first output opening and a second output opening, connected to the first and second chamber, of a hydraulic actuator, at least one bridge for selective communication, by way of the shuttle, of the delivery port with the first or second chambers of the actuator, for actuation thereof, a unidirectional hydrostat connected to the bridge to draw selectively a pressure signal of the load of the actuator, the signal for adjusting selectively the delivery pressure of the pump so as to keep substantially constant the pressure drop between the delivery port and the actuator in any load condition.
    Type: Grant
    Filed: May 24, 2007
    Date of Patent: September 1, 2009
    Assignee: Hydrocontrol S.p.A.
    Inventors: Claudio Bulgarelli, Massimiliano Musiani
  • Publication number: 20080282691
    Abstract: A pressure-compensating directional control valve, for actuating hydraulic actuators, comprising at least one modular valve body, with one through receptacle for a slidable shuttle, a driving fluid delivery port connected to a pump, a discharge fluid port, a first output opening and a second output opening, connected to the first and second chamber, of a hydraulic actuator, at least one bridge for selective communication, by way of the shuttle, of the delivery port with the first or second chambers of the actuator, for actuation thereof, a unidirectional hydrostat connected to the bridge to draw selectively a pressure signal of the load of the actuator, the signal for adjusting selectively the delivery pressure of the pump so as to keep substantially constant the pressure drop between the delivery port and the actuator in any load condition.
    Type: Application
    Filed: May 24, 2007
    Publication date: November 20, 2008
    Inventors: Claudio Bulgarelli, Massimiliano Musiani
  • Patent number: 7219593
    Abstract: The invention refers to the field of hydraulic control devices and refers to a saturation-proof hydraulic control device with two or more elements; each element is composed of a six-way, two-position spool (4) of the proportional type, a pressure compensator (3), also of the proportional type, notches on the spool for a correct operation and pressure selector members (MS) equipped with spring (M7) that connect the various elements so that the work function at higher pressure sends the pressure to the spring side of its own pressure compensator (3), making it operate as check valve, and sending the pressure existing between spool (4) and pressure compensator (3) to the spring side of the compensators (3) of the other elements and to the pump (P). The spring (M7) must generate a minimum load that is slightly greater than the pressure drop of the maximum flow-rate through the local pressure compensator (3).
    Type: Grant
    Filed: June 21, 2005
    Date of Patent: May 22, 2007
    Assignee: Walvoil S.p.A.
    Inventor: Ulderico Busani
  • Patent number: 6662706
    Abstract: A hydraulic system comprises a variable displacement pump. The hydraulic system includes a first device capable of being hydraulically powered by the pump and a reversing device adapted to cause the first device to autoreverse. The hydraulic system also includes an isolation device adapted to prevent pressure surges resulting from a source other than the first device from actuating the reversing device, thereby preventing undesirable autoreversing of the first device.
    Type: Grant
    Filed: May 30, 2002
    Date of Patent: December 16, 2003
    Assignee: Finn Corporation
    Inventor: Douglas E. Wysong
  • 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: 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: 6192928
    Abstract: A valve assembly for pressure adapted and volumetric flow adapted supply of at least one user may be supplied with hydraulic fluid or connected to a tank via two work ports of a continuously adjustable directional control valve. To the two work ports of the valve assembly a common pressure compensator is associated, the piston of which is guided in axial translation in an axial bore of the directional control valve spool, so that one of the two work ports may optionally be connected to the pump port upon suitable actuation of the directional control valve. At both end surfaces of the directional control valve spool and at the spring side of the pressure compensator piston, there acts a respective control pressure which, for example, corresponds to the highest system load pressure, the individual load pressure, or a pressure derived therefrom.
    Type: Grant
    Filed: May 19, 1999
    Date of Patent: February 27, 2001
    Assignee: Mannesmann Rexroth AG
    Inventors: Burkhard Knoell, Winfried Rueb
  • Patent number: 6158462
    Abstract: The present invention is directed to a hydraulic pressure control device which can overcome problems, such as a shock to an actuator or a pressure boost phenomenon involving a rapid increase in pump delivery pressure, conventionally encountered when a directional control valve is switched. The hydraulic pressure control device is constructed such that first and second connecting ports are connected to a tank when a directional control valve is in its neutral position, one of the first and second connecting ports is cut off from the tank and connected to an actuator and the other is cut off from the tank and closed when the directional control valve has been switched, in accordance with a position to which the directional control valve has been switched, and a maximum pilot pressure selectively taken from between a pressure compensating valve and a pair of check valves is introduced into a pilot line.
    Type: Grant
    Filed: August 19, 1998
    Date of Patent: December 12, 2000
    Assignee: Kayaba Industry Co., Ltd.
    Inventors: Masao Kashiwagi, Masayuki Nakamura
  • Patent number: 6134887
    Abstract: A hydraulic control circuit for, for example, working members of earth-moving machines such as backhoe loaders. A first and a second control section (9,10) are coupled to first and second linear hydraulic actuators (1,2; 3-8) through respective first a second hydraulic spool valves (21,22; 23-28), and supply (11) of a hydraulic fluid under pressure is connected in parallel with the two control sections (9,10) via a feed line (13). A load sensing circuit (16) is associated with the first and second spool valves. The control circuit includes a series-parallel connection circuit (36) of the load sensing circuit (16), and additional optional devices ensuring a higher operative functionality of the working members of the machine.
    Type: Grant
    Filed: December 21, 1994
    Date of Patent: October 24, 2000
    Inventors: Elio Bertotti, Giovanni Maria Testa
  • Patent number: 5957159
    Abstract: A pair of directional control valves 8 and a pair of hold check valves 9 are disposed respectively between a pair of metering notches 6, which are formed in a land 4-1 of a spool 2 and have functions of both flow rate control and direction control, and a pair of actuator ports A, B. Each hold check valve comprises a valve body 90 in the form of a hollow spool having a seat portion 12 formed on an outer periphery and being subject to a pressure developed in an outlet passage 10 communicating with one of the actuator ports to act in the valve-closing direction. Each flow distribution valve comprises a valve body 80 being slidably fitted in the valve body 90 and having a front surface positioned to face an inlet passage 7 communicating with the metering notch and a rear surface positioned to face an control pressure chamber 30 communicating with a signal detecting hydraulic line.
    Type: Grant
    Filed: September 17, 1998
    Date of Patent: September 28, 1999
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Kinya Takahashi, Yoshizumi Nishimura, Yusaku Nozawa, Nobuhiko Ichiki, Minoru Aoki
  • Patent number: 5890362
    Abstract: An improved pressure-compensated hydraulic system for feeding hydraulic fluid from a variable displacement pump to multiple hydraulic actuators. A separate valve section controls the fluid flow between the pump and a different actuator. Each valve section has a pressure compensating valve with a valve member and poppet within a bore and biased apart by a spring. The poppet acts as a check valve which prevents fluid flow from the actuator through the valve section to the pump when the back pressure from the load exceeds the pump supply pressure. A pressure differential between the load-dependent pressure and the actuator pressure determines a position of the valve member which controls the pressure applied to the pump pressure control input.
    Type: Grant
    Filed: October 23, 1997
    Date of Patent: April 6, 1999
    Assignee: Husco International, Inc.
    Inventor: Raud A. Wilke
  • Patent number: 5724878
    Abstract: In a hydraulic operating mechanism for a convertible top, a pressure sensor (12) is incorporated into a common pressure circuit (P) of the hydraulic cylinders (1 through 4) and connected with a control unit which is connected to the switching elements (V1 through V4) of the hydraulic cylinders (1 through 4), and its output signal in relation to time, together with the preset switching sequences of the individual switching elements (V1 through V4), serves to control the end positions of the individual hydraulic cylinders (1 through 4). The control can thus be incorporated in the operating mechanism without expensive separate end position switches at each hydraulic cylinder (1 through 4) or appurtenant actuation element, simplifying the overall design.
    Type: Grant
    Filed: July 25, 1996
    Date of Patent: March 10, 1998
    Assignees: Hoerbiger GmbH, Bara Electronic GmbH
    Inventors: Klaus Stolle, Ulrich Baudermann
  • Patent number: 5715865
    Abstract: An improved pressure-compensated hydraulic system for feeding hydraulic fluid to one or more hydraulic actuators. A remotely located, variable displacement pump provides an output pressure equal to input pressure plus a constant margin. A pressure compensation systems requires that a load-dependent pressure be provided to the pump input through a load sense circuit. A reciprocally spooled, multi-ported isolator transmits the load-dependent pressure to the pump input but prevents fluid in the load sense circuit from leaving the load sense circuit and flowing through a relatively long conduit leading to the remotely located pump. In a multi-valve array, at least one valve section has a backflow-preventing shuttle valve which prevents backflow through the pressure compensation system if a main relief valve is operative.
    Type: Grant
    Filed: November 13, 1996
    Date of Patent: February 10, 1998
    Assignee: Husco International, Inc.
    Inventor: Raud A. Wilke
  • Patent number: 5687568
    Abstract: A hydraulic motor system minimizes wasted power by using a plurality of fixed displacement hydraulic motors to drive a drive shaft in a cooperative manner. The motors are selectively switched into operation in response to variations in fluid pressure. As a consequence the hydraulic fluid acts upon a motor system having an effective combined displacement for producing a predetermined shaft rotation rate at the volumetric flow rate which caused the pressure condition. The invention is disclosed as having particular utility for driving a cooling fan for an automotive engine.
    Type: Grant
    Filed: March 13, 1996
    Date of Patent: November 18, 1997
    Assignee: ITT Automotive Electrical Systems, Inc.
    Inventor: Jeffrey J. Buschur
  • Patent number: 5651390
    Abstract: A direction control valve is formed by providing a main spool for establishing and blocking communication between an inlet port, first and second actuator ports and first and second tank ports. A pressure compensation valve comprising a check valve portion and pressure reduction portion is provided for compensating the pressurized fluid with a load pressure and supplying it to the inlet port. A plurality of valve blocks are connected to each other with respective first and second tank ports and respective pump ports in fluid communication. A pump port of one of the valve blocks is connected to a main inlet port, and a tank port of one of the valve blocks is connected to a main tank port. Thus, a hydraulic circuit for distributing a pressurized fluid from a single hydraulic pump to a plurality of actuators is provided.
    Type: Grant
    Filed: April 10, 1995
    Date of Patent: July 29, 1997
    Assignee: Kabushiki Kaisha Komatsu Seisakusho
    Inventors: Kazuyoshi Ishihama, Kazunori Ikei, Kazuo Uehara
  • Patent number: 5640850
    Abstract: A one-piece terminal block (73) is provided as a hydraulic linking element as well as a mechanical carrier for control valves (68 to 72) of a boom control unit, for an operating mode selector valve (74), and for switching elements of a pressure supply device (77). A pressure line (119), return line (132), control line (166), and a further return line (167,168) are designed as bores extending in an axial direction of the terminal block, from which connection channels originate which terminate within terminal arrays (163, 163.sup.I to 163.sup.IV) in a bore layout for the valves. Sections (102') of a load feedback line (102), which are serially connectable to each other by comparative valves (114) are formed by individual longitudinal bores (188,188.sup.I to 188.sup.
    Type: Grant
    Filed: May 5, 1995
    Date of Patent: June 24, 1997
    Assignee: Putzmeister-Werk Maschinenfabrik GmbH
    Inventors: Hartmut Benckert, Hans Renz, Werner Muenzenmaier, Gabriel Galambos
  • Patent number: 5609088
    Abstract: A hydraulic control system for excavators includes a variable displacement pump for producing a variable volume of pressurized working fluid, a hydraulic swing motor rotatably driven by the working fluid and a flow control valve operable to control flow of the working fluid with respect to the swing motor. The first flow control valve comprises a valve body and a valve spool slidably fitted into the valve body for selective shifting movement between a first operative position, a second operative position and a neutral position.
    Type: Grant
    Filed: July 25, 1995
    Date of Patent: March 11, 1997
    Assignee: Daewoo Heavy Industries, Ltd.
    Inventor: Hee W. Park
  • Patent number: 5579642
    Abstract: An improved pressure-compensated hydraulic system for feeding hydraulic fluid to one or more hydraulic actuators. A remotely located, variable displacement pump provides an output pressure equal to input pressure plus a constant margin. A pressure compensation systems requires that a load-dependent pressure be provided to the pump input through a load sense circuit. A reciprocally spooled, multiported isolator transmits the load-dependent pressure to the pump input but prevents fluid in the load sense circuit from leaving the load sense circuit and flowing through a relatively long conduit leading to the remotely located pump. In a multi-valve array, at least one valve section has a backflow-preventing shuttle valve which prevents backflow through the pressure compensation system if a main relief valve is operative.
    Type: Grant
    Filed: May 26, 1995
    Date of Patent: December 3, 1996
    Assignee: Husco International, Inc.
    Inventors: Raud A. Wilke, Eric P. Hamkins, Michael C. Layne, Leif Pedersen, Lynn A. Russell
  • Patent number: 5561978
    Abstract: A hydraulic motor system minimizes wasted power by using a plurality of fixed displacement hydraulic motors to drive a drive shaft in a cooperative manner. The motors are selectively switched into operation in response to variations in fluid pressure. As a consequence the hydraulic fluid acts upon a motor system having an effective combined displacement for producing a predetermined shaft rotation rate at the volumetric flow rate which caused the pressure condition. The invention is disclosed as having particular utility for driving a cooling fan for an automotive engine.
    Type: Grant
    Filed: November 17, 1994
    Date of Patent: October 8, 1996
    Assignee: ITT Automotive Electrical Systems, Inc.
    Inventor: Jeffrey J. Buschur
  • Patent number: 5546750
    Abstract: A control device provides a reliable way of pressure controlling a hydraulic distributor and an associated first hydraulic circuit when pressurized hydraulic fluid is simultaneously supplied to at least one other hydraulic circuit. Pilot pressure oil enters and exits the distributor through inlet and outlet passages in the pilot line. An apparatus for regulating pilot oil flow rate is interposed between the pilot line inlet passage and the hydraulic fluid line. The device includes a pressure head detection apparatus having inlet ends connected to the pilot line inlet passage and to the hydraulic circuit and an outlet end connected to the hydraulic fluid source for controlling the flow rate of the hydraulic fluid based on the highest pressure requirement.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: August 20, 1996
    Assignee: Rexroth-Sigma
    Inventor: Emmanuel Richer
  • Patent number: 5535663
    Abstract: An operating valve assembly incorporates a pressure compensation valve and is capable of contributing down-sizing of a hydraulic circuit. The valve assembly includes an operating valve, compensation valves and a load pressure detecting portion. A valve body of the operating valve defines a spool bore extending laterally through the valve body at a vertically intermediate portion of the valve body, a load pressure detecting port at a laterally intermediate portion of the spool bore, and a respective pump port, actuator port and tank port at each side of the load pressure detecting port. The operating valve also includes a spool within the spool bore. The pressure compensation valves are arranged at left and right sides of an upper portion of the valve body and the load pressure detecting portion for supplying load pressure to the load pressure detecting port is formed in the spool.
    Type: Grant
    Filed: October 7, 1994
    Date of Patent: July 16, 1996
    Assignee: Kabushiki Kaisha Komatsu Seisakusho
    Inventors: Koji Yamashita, Teruo Akiyama, Kouji Saito, Shinichi Shinozaki
  • Patent number: 5481873
    Abstract: A hydraulic drive system for actuating a reciprocating member such as a polished rod in a pump jack device, and for acting as a counterbalance and/or for energy conservation. The system has two hydraulic circuits and a prime mover. A first circuit includes a cylinder for driving an output member which may be connected to the polished rod, a first pump of the variable displacement, reversible flow type, together with a pair of fluid lines forming with the cylinder a closed-loop circuit. A controller is programmed to control the setting of the first pump so as to establish the velocity profile of the output member. A second hydraulic circuit is also in the form of a closed-loop containing first and second pumps, at least one of which is of the variable displacement type and is also controlled by the controller.
    Type: Grant
    Filed: November 17, 1994
    Date of Patent: January 9, 1996
    Assignee: Qsine Corporation Limited
    Inventors: Minoru Saruwatari, Kevin S. Saruwatari, Fredrick A. Bourgonje
  • Patent number: 5481872
    Abstract: Simultaneous operation efficiency in a case where a plurality of actuators are operated by one or a plurality of hydraulic pumps is improved. A delivery pressure passage (1a) of one hydraulic pump (1) and that (1a) of the other hydraulic pump (1) communicate with each other through a first short-circuit passage (39) via a pair of check valves (38, 38), and an unload valve (40) is provided in this first short-circuit passage (39). The load pressure introduction passages (6, 6) on the left and right hydraulic pumps (1, 1) communicate with each other through a second short-circuit passage (36) via a pair of check valves (35, 35), and a relief valve (37) is provided in this short-circuit passage (36).
    Type: Grant
    Filed: September 23, 1994
    Date of Patent: January 9, 1996
    Assignee: Kabushiki Kaisha Komatsu Seisakusho
    Inventors: Tadao Karakama, Teruo Akiyama, Kouji Yamashita, Naoki Ishizaki
  • Patent number: 5471837
    Abstract: A hydraulic control system is designed to permit the use of a plurality of small substantially identical existing valve assemblies in place of a lesser number of larger valve assemblies. In one embodiment, a first pair of variable displacement load sensing hydraulic pumps communicate with a manifold connected to a first valve assembly and another pair of variable displacement load sensing hydraulic pump communicate with a second manifold connected to second and third valve assemblies. A crossover conduit interconnects the manifolds so that fluid from all four pumps can be used by any one of the valve assemblies or shared by two or all three of the valve assemblies. In another embodiment, a third pair of variable displacement load sensing hydraulic pumps communicate with the first manifold 12 which also has another valve assembly connected thereto.
    Type: Grant
    Filed: September 3, 1993
    Date of Patent: December 5, 1995
    Assignee: Caterpillar Inc.
    Inventor: Donald L. Bianchetta
  • Patent number: 5460001
    Abstract: A flow control system is arranged in a hydraulic circuit provided with a variable displacement hydraulic pump, plural actuators and a pump controller. The pump controller controls the displacement of the pump so that a delivery pressure becomes higher by a predetermined value than a maximum load pressure of the plural actuators, whereby the flow rate of pressure oil to the actuators is controlled. The system includes plural valve units connected between the pump and the actuators. Each valve unit has an operating and correcting variable restrictors. The system also includes pressure compensation valves, which are each arranged on an upstream side of a restrictor group consisting of the operating and correcting variable restrictors.
    Type: Grant
    Filed: November 7, 1994
    Date of Patent: October 24, 1995
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hideyo Kato, Masami Ochiai
  • Patent number: 5458049
    Abstract: Material such as trash or refuse is packed in a container by opposed hydraulic packing and ejecting cylinders. Each cylinder is controlled by a hydraulic control valve with the control valve controlling the ejecting cylinder being, in effect, operated by the control valve for the packing cylinder. This is accomplished by sensing the pressure applied to the packing cylinder and when the pressure reaches a predetermined level, a pilot dump valve, in the ejecting cylinder is opened to allow the piston in the ejecting cylinder to retreat. When the pilot pressure drops below the predetermined level, the pilot dump valve closes, allowing the packing cylinder to exert additional packing force. In this way the piston in the ejecting cylinder inches back and the material is intermittently packed. An anti-cavitation check is provided so as to fill the chamber of the ejecting cylinder as the piston retracts.
    Type: Grant
    Filed: May 31, 1994
    Date of Patent: October 17, 1995
    Assignee: Dana Corporation
    Inventors: Kevin L. Shinler, Alvin S. Rost
  • Patent number: 5442912
    Abstract: A hydraulic recovery device in a hydraulic system having a pump (1) driving a plurality of actuators through a plurality of control valves (2, 3), the hydraulic recovery device comprising a variable resistance valve (6, 60) in a first line being controlled by a control signal (Px), a third line, a check valve (7) disposed in the third line for allowing the hydraulic fluid to flow only in a direction from the first line toward the second line.
    Type: Grant
    Filed: July 11, 1994
    Date of Patent: August 22, 1995
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Toichi Hirata, Genroku Sugiyama, Masami Ochiai
  • Patent number: 5435132
    Abstract: The invention relates to a method for, in a hydrostatic transmission having a preferably variable displacement hydraulic pump (P) feeding a number of hydraulic motors (M1, M2, M3, M4) provided in association with respective drive wheels, drive tracks or corresponding drive apparatus, mutually balancing the flow of hydraulic fluid through the different hydraulic motors (M1-M4) by individually controlling of the flow from and/or to the same, whereby the individual flows of hydraulic fluid through the respective hydraulic motors (M1-M4) are detected and compared across respective restrictions (14, 15) being variable dependent on the total flow but being of mutually equal size and whereby, for optimum control or balancing, the detected differences in flow through the different hydraulic motors are in themselves used directly for the balancing.
    Type: Grant
    Filed: May 13, 1994
    Date of Patent: July 25, 1995
    Inventors: Jan Lindholm, Thomas Lindholm
  • Patent number: 5386697
    Abstract: Hydraulic actuators are fed by a single flow-rate generator, each being connected to it through a proportional directional valve, the unit including at least one auxiliary valve fed by the flow-rate generator and producing a pressure which is normally equal to a regulation pressure increased by a constant, and in each proportional directional valve an actuating device causes the compensating spool to respond to the pressure produced by the auxiliary valve.
    Type: Grant
    Filed: July 27, 1993
    Date of Patent: February 7, 1995
    Assignee: Marrel
    Inventors: Jean-Louis Claudinon, Andre Rousset
  • Patent number: 5353594
    Abstract: In a driving mechanism of a circuit breaker having first and second hydraulic operation apparatuses respectively driving a main contact and a resistor contact, a sequential control valve is provided between the first and second hydraulic operation apparatuses. The sequential control valve detects the operation of a differential piston for opening the main contact and switching the differential piston for sequentially opening the resistor contact after the opening of the main contact.
    Type: Grant
    Filed: April 22, 1993
    Date of Patent: October 11, 1994
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toru Yamashita, Yoshiki Hirano
  • Patent number: 5319933
    Abstract: A hydraulic circuit for controlling the speed of multiple hydraulic fluid power devices when the flow demand of the devices exceeds the flow capacity of a pressure source supplying hydraulic fluid under pressure to the devices has multiple pressure controlled proportional flow supply valves for controlling the supply of hydraulic fluid to the power devices. Load sense pressures which indicate the pressure delivered by the valves to the corresponding devices are compared to determine the highest load sense pressure, which is compared to the supply pressure by a proportional speed sensing valve to regulate the pilot pressure. In the preferred embodiment, the pilot pressure is regulated by the proportional speed sensing valve to be equal to the differential between the supply pressure and the highest load sense pressure, and a limit control is provided in one form of the proportional speed sensing valve.
    Type: Grant
    Filed: February 26, 1993
    Date of Patent: June 14, 1994
    Assignee: Applied Power Inc.
    Inventors: Carl-Johan Omberg, James P. Janecke
  • Patent number: 5315827
    Abstract: The flow rate of oil under pressure for operating an attachment for a hydraulic excavator or the like according to the type of attachment is controlled by a simple hydraulic circuit, capable of easily switching the flow rate and also capable of finely adjusting the flow rate. The circuit has directional control valves (2-4, 6-8), pressure compensating valves (17, 18) disposed at outlet ports of each of the directional control valves, load sensing valves (23, 24) for controlling discharges from the variable capacity type main hydraulic pumps (1, 5), and circuits (21, 22) for feeding back the maximum valve of load pressure between each actuator and the associated direction control valve to the pressure compensating valves and the load sensing valves via a shuttle valve (20). A directional control valve (4), which controls the attachment, has a restricting element for restricting an opening area of a spool of the directional control valve.
    Type: Grant
    Filed: July 17, 1992
    Date of Patent: May 31, 1994
    Assignee: Kabushiki Kaisha Komatsu Seisakusho
    Inventors: Hiroshi Imai, Daigiro Ito
  • Patent number: 5313795
    Abstract: The invention is an improvement in a control system having first, second and third sources of fluid at differing pressures. The improvement comprises a tripath pressure selector network connected to the first and second sources. A pressure-sensing device connects the network and the third source when the third source is at a predetermined minimum pressure. The invention has particular utility in mobile construction machinery having, e.g., steering, implement and brake hydraulic circuits, at differing pressures. In one embodiment, the third source is a brake hydraulic circuit. The improvement helps assure that adequate pilot pressure is available for a "downstream" pilot control valve.
    Type: Grant
    Filed: December 17, 1992
    Date of Patent: May 24, 1994
    Assignee: Case Corporation
    Inventor: Donnell L. Dunn
  • Patent number: 5305789
    Abstract: A pressure compensating hydraulic directional valve comprising: a body provided with a movable slide; a passage through the body for connecting a distribution chamber associated with the slide to working orifices, the distribution chamber being selectively connectable to an admission orifice by the slide when moved; a load sensing line channel combined with means for selecting the maximum pressure selected from the pressure in the channel and the pressure of the fluid in the valve; and pressure compensating means placed in the passage and responsive to the difference between the pressure in the passage and the pressure in the channel to generate a fixed pressure drop in the pressurized fluid flowing through the passage towards the working orifices, the pressure compensating means being combined with the maximum pressure selecting means in such a manner that if the pressure in the channel is greater than or equal to the pressure of the fluid from the slide, then no communication exists between the passage and
    Type: Grant
    Filed: April 6, 1993
    Date of Patent: April 26, 1994
    Assignee: Rexroth-Sigma
    Inventor: Michel Rivolier
  • Patent number: 5305680
    Abstract: A control device for hydraulic operating cylinders of a tailgate of a vehicle to determine maximum pressures arising in the operation and, particularly, overloading of the tailgate, resulting in excessive pressures. A power-driven hydraulic pump (1) is connected to a reservoir (4) and, via branch lines (8', 8"), with associated gate control valves (10, 13) which include a closing cylinder (14) for the tailgate. A pressure intensifier piston-cylinder unit (15) is connected parallel to the branch pipes. An electric pressure-sensitive switch (16), which is also connected to a counter (17) and to an interrupter switch (18) for the electric pump motor, switches off the pump motor (2) when the predetermined pressure is exceeded. This switch is connected to the closing cylinder (14) for the tailgate.
    Type: Grant
    Filed: June 30, 1992
    Date of Patent: April 26, 1994
    Inventor: Gunter Weber
  • Patent number: 5303551
    Abstract: The present invention relates to a flow rate control apparatus for a hydraulic pump which is employed suitably in a hydraulic excavator or a hydraulic crane and driven by a rotating force of a motor. The flow rate control apparatus controls the discharging flow rate of the hydraulic pump to utilize the output power of the motor without an overload applied to the motor, and optimally controls the output flow rate of the pump depending upon an operation signal to provide an excellent operating characteristic to an operator under a high load operating condition applied to a hydraulic machine having hydraulic actuators driven on the basis of the discharge flow of the hydraulic pump.
    Type: Grant
    Filed: November 25, 1992
    Date of Patent: April 19, 1994
    Assignee: Samsung Heavy Industries Co., Ltd.
    Inventor: Jin-Han Lee
  • Patent number: 5301505
    Abstract: A fail safe hydraulic system which includes a pressurized fluid storage which is capable of delivering fluid to the actuator to return it to its inoperative position should the actuator system suffer a loss of power and a apparatus for signaling a controller when the pressurized fluid storage has been charged with fluid, wherein fluid from the reservoir cannot be delivered to the actuator until the pressurized fluid storage has been charged with fluid.
    Type: Grant
    Filed: December 4, 1992
    Date of Patent: April 12, 1994
    Inventor: John J. Wright
  • Patent number: 5297381
    Abstract: In a hydraulic system several consumers (5'; 5"; 5'") are supplied by a common regulating pump (1). The regulating pump (1) is controlled as a function between the pump pressure (delta P) and the highest load pressure. This pressure difference (delta P.sub.max) is related to a minimum pressure difference (delta P.sub.min), and the comparison signal is input in a control unit (21) to influence the reference value signals (S1, S2, S3) by which the individual valves (6'; 6"; 6'") are controlled.
    Type: Grant
    Filed: October 15, 1992
    Date of Patent: March 29, 1994
    Assignee: Barmag AG
    Inventors: Otwin Eich, Franz-Peter Salz
  • Patent number: 5295353
    Abstract: A device for controlling a vehicle for loading work and equipped with a plurality of hydraulic pumps of fixed capacity for loading work and a torque converter driven from an engine, an electronic control governor for optionally selecting output characteristic in steps for controlling output of the engine, changeover valves disposed in the circuit on the downstream side of one pump for changing over the flow of pressure oil to a drain circuit in response to working oil pressure or an electric signal, a selection switch for selecting the output characteristics, a governor controller for controlling engine the output characteristic as selected by the switch, and control circuits for actuating the changeover valves in response to the position of the selection switch.
    Type: Grant
    Filed: October 23, 1992
    Date of Patent: March 22, 1994
    Assignees: Kabushiki Kaisha Komatsu Seisakusho, Komatsu MEC Kabushiki Kaisha
    Inventor: Masanori Ikari
  • Patent number: 5285642
    Abstract: A load sensing control system for a hydraulic machine sets a variable target differential pressure between a delivery pump pressure and a load pressure of an actuator. A control factor is determined that becomes larger as the deviation between the target differential pressure and the actual differential pressure is increased, and that becomes smaller as the differential pressure deviation is decreased. The control factor also becomes larger as the target differential pressure becomes smaller. The target displacement volume for the hydraulic pump is based on the differential pressure deviation, which is calculated from the target differential pressure and the control factor.
    Type: Grant
    Filed: May 19, 1992
    Date of Patent: February 15, 1994
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hiroshi Watanabe, Yasuo Tanaka, Eiki Izumi, Hiroshi Onoue, Shigetaka Nakamura
  • Patent number: 5267440
    Abstract: In a controller (229) of a hydraulic control system for construction machines, a valve control signal calculating function (301) works such that when an operation pattern signal (A-I) for actuators (201, 202 . . . ) is outputted, it selects corresponding one of plural output patterns for an auxiliary valve control pressure stored, as a function of a differential pressure signal between a pump delivery pressure and a maximum load pressure, in relation to the operation pattern signals, followed by calculating an auxiliary valve control pressure (Pc) dependent upon the differential pressure signal based on the selected output pattern, and also selects corresponding one of plural sets of rates of change (K . . . , K . . . ) for the auxiliary valve control pressure stored in relation to the operation pattern signals, followed by combining the calculated auxiliary valve control amount with the selected set of speed changes to calculate each of valve control signals (S21-S26).
    Type: Grant
    Filed: May 4, 1992
    Date of Patent: December 7, 1993
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Kazunori Nakamura, Yusuke Kajita, Toichi Hirata, Genroku Sugiyama, Hiroshi Onoue, Hideaki Tanaka, Osamu Tomikawa, Masakazu Haga, Hiroshi Watanabe
  • Patent number: 5259192
    Abstract: This invention provides a hydraulic circuit system capable of reducing the flow rate distribution error in supplying pressurized fluid from a single hydraulic pump into a plurality of hydraulic actuators, and also supplying pressurized fluid quickly. The circuit is simplified to reduce manufacturing costs.
    Type: Grant
    Filed: July 22, 1992
    Date of Patent: November 9, 1993
    Assignee: Kabushiki Kaisha Komatsu Seisakusho
    Inventors: Tadao Karakama, Teruo Akiyama
  • Patent number: 5255590
    Abstract: A hydraulic base-load motor (M1) drives a load with the working pressure generated at the motor rising with the load. When the working pressure reaches an upper limit pressure, a hydraulic stand-by motor (M2) is switched on. Since the pressure drops upon switching on the stand-by motor, the control device is designed such that, upon reaching a lower limit pressure, it deactivates the stand-by motor again, the lower limit pressure being less than half the upper limit pressure. This switching hysteresis prevents a repeated switching over of the stand-by motor.
    Type: Grant
    Filed: June 20, 1991
    Date of Patent: October 26, 1993
    Assignee: Ing. Guenter Klemm Bohrtechnik GmbH
    Inventor: Guenter W. Klemm