Patents by Inventor Masakazu Haga

Masakazu Haga has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6564480
    Abstract: In a working apparatus, a recessed portion is formed at an end surface of a pin provided at a boom to house a case of an angle sensor in the recessed portion. A flange is projected from the case along the direction of the axis of an input shaft so as to enclose the input shaft outside the movement range of a lever. By projecting the flange further out than the distance over which the input axis projects out, the protection provided by the flange for the input shaft is enhanced.
    Type: Grant
    Filed: November 28, 2000
    Date of Patent: May 20, 2003
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Sadahisa Tomita, Genroku Sugiyama, Masakazu Haga, Ryohei Suzuki, Toshio Hasegawa, Koji Tahara
  • Patent number: 6430490
    Abstract: Whether a previously computed valve command value Y−1 is within a neutral zone ±&agr; is determine. If the determination result is “Yes”, processing to compute a valve command value for a neutral dead zone is executed. If the determination result is “No”, processing to compute a valve command value for a driving zone is executed. In the latter case, by using a valve command value X and the previously computed valve command value Y−1, it is determined in which one of acceleration, deceleration/stop, and lever-reversed condition is the operating status, and a maximum setting rate in one of acceleration, deceleration/stop, and lever-reversed condition is computed from a corresponding function &Dgr;Y=fmax1(X), etc. Then, a control signal is computed while restraining a change rate of the operational signal to be kept not more than the computed maximum change rate, and a flow control valve 3 is controlled in accordance with the computed control signal.
    Type: Grant
    Filed: March 27, 2001
    Date of Patent: August 6, 2002
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hiroshi Watanabe, Shuji Ohira, Kazuo Fujishima, Hiroshi Ogura, Masakazu Haga, Sadahisa Tomita
  • Patent number: 6275757
    Abstract: An area limiting excavation control system in an excavation machine having a front device, includes means for setting in advance, an area where the front device is movable. A control unit calculates the position and posture of the front device based on signals from angle sensors. When the front device is inside the set area near the boundary thereof, the control unit calculates a limit value (a) of a bucket tip speed so that a moving speed of the front device in the direction vertical to the boundary of the set area is restricted, and then modifies the limit value (a) depending on a load pressure of an arm cylinder detected by a pressure sensor. It further calculates, from the limit value (a), a limit value of the component of a boom-dependent bucket tip speed vertical to the boundary of the set area, and then modifies a boom operation signal so that the boom-dependent bucket tip speed will not exceed the above limit value.
    Type: Grant
    Filed: February 19, 1999
    Date of Patent: August 14, 2001
    Assignee: Hitachi Construction Machinery Co. Ltd.
    Inventors: Hiroshi Watanabe, Kazuo Fujishima, Masakazu Haga
  • Patent number: 6169948
    Abstract: A setting device for a front control system for a construction machine includes a direct setting switch for instructing a direct teaching setting, a numeral input key consisting of up- and down-keys for instructing a numeral input setting, a setting changeover switch for changing over a setting mode from the direct teaching setting to the numeral input setting, an LED lighting up when the setting changeover switch is pushed, an area limiting switch for starting an area limiting excavation control, an LED lighting up when the area limiting switch is pushed, and a display screen for indicating the position of a bucket end of a front device in terms of a numeral value when the setting changeover switch is not pushed, and indicating the numeral value input with the numeral input with the numeral input setting when the setting changeover switch is pushed.
    Type: Grant
    Filed: June 20, 1997
    Date of Patent: January 2, 2001
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Kazuo Fujishima, Hiroshi Watanabe, Masakazu Haga, Takashi Nakagawa
  • Patent number: 6076029
    Abstract: A slope excavation control system for a hydraulic excavator and a slope excavation method using a hydraulic excavator include an external reference 80 which extends horizontally in the direction of advance of a target slope face. A vertical distance hry and a horizontal distance hrx from the external reference to a reference point on a target slope face, and an angle of the target slope face are set by using a setting device. When a front reference provided at a bucket end is aligned with the external reference and an external reference setting switch is depressed, a control unit calculates a vertical distance hfy and a horizontal distance hfx from a body center of the excavator to the external reference, then calculates a vertical distance hsy and a horizontal distance hsx from the body center to the reference point of the target slope face by using the distances hsy and hsx as modification values.
    Type: Grant
    Filed: October 8, 1998
    Date of Patent: June 13, 2000
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hiroshi Watanabe, Kazuo Fujishima, Masakazu Haga
  • Patent number: 5968104
    Abstract: An area where a front device (1A) is allowed to move is set beforehand and the operation of the front device is controlled so that the front device will not go out of the set area. For this control process, an arm cylinder speed calculating portion (9d) of a control unit (9) estimates an arm cylinder speed for use in control by taking the sum of a low-frequency component of an arm cylinder speed which is derived through coordinate transformation and differentiation of an arm rotational angle detected by an angle sensor (8b), and a high-frequency component of an arm cylinder speed which is derived from a command value applied from a control lever unit (14b) to a flow control valve (15b) for an arm and a flow rate characteristic of the flow control valve (15b). The control unit controls the operation of the front device with the estimated operating speed.
    Type: Grant
    Filed: June 23, 1997
    Date of Patent: October 19, 1999
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Eiji Egawa, Kazuo Fujishima, Masakazu Haga, Hiroshi Watanabe
  • Patent number: 5960378
    Abstract: An excavation area setting system for area limiting excavation control in construction machines, with the excavation control being performed to calculate a target speed vector for control of a front device on the basis of a body, modify the target speed vector to limit a moving speed of the front device in the direction toward a boundary of a preset excavation area when the front device comes close to the boundary of the excavation area, and move the front device along the boundary of the excavation area. To set the excavation area, an external reference is installed horizontally outside the hydraulic excavator and a depth from the external reference to the boundary of the excavation area is set by using a setting device. The excavation area is set in a manner matched with the excavation control in which calculation is executed based on the position of the body.
    Type: Grant
    Filed: January 16, 1997
    Date of Patent: September 28, 1999
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hiroshi Watanabe, Toichi Hirata, Masakazu Haga, Kazuo Fujishima
  • Patent number: 5957989
    Abstract: A calculating portion 7a calculates a distance from the tip end of a front device to an interference prevention area, and a detection line 7m detects a moving speed of a boom 1. If the tip end of the front device comes close to the interference prevention area when the boom 1 is moving upward, control is made such that, while continuing to move the boom 1 upward, a control gain calculating portion 7h and a multiplier 7i cooperatively calculate a target speed of an arm in the arm dumping direction (interference avoiding direction) corresponding to the boom-up speed, and an input limit value calculating portion 7c, an adder 7j and a minimum value selecting portion 7f cooperatively control the arm to move in the interference avoiding direction relative to a vehicle body.
    Type: Grant
    Filed: December 4, 1996
    Date of Patent: September 28, 1999
    Assignee: Hitachi Construction Machinery Co. Ltd.
    Inventors: Eiji Egawa, Hiroshi Watanabe, Hiroyuki Adachi, Junichi Hosono, Toshiaki Nishida, Mitsuo Kihara, Masakazu Haga
  • Patent number: 5918527
    Abstract: A locus control system of hydraulic excavators whereby a target locus for a front device is set beforehand. A control unit calculates a position and posture of the front device based on signals from angle sensors, and calculates a target speed vector of the front device based on signals from control lever devices. Through this calculation process, the control unit maintains the target speed vector as it is when the front device is not near the target locus, and modifies the target speed vector to a vector pointing to a second point on the target locus advanced in the excavating direction by a second distance from a first point located on the target locus at a minimum distance from a tip of the front device, when the front device is near the target locus.
    Type: Grant
    Filed: April 23, 1997
    Date of Patent: July 6, 1999
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Masakazu Haga, Hiroshi Watanabe, Kazuo Fujishima
  • Patent number: 5887365
    Abstract: In an oil temperature detecting/calculating portion 9p, threshold values T.sub.1, T.sub.2 are set beforehand to divide a range of oil temperature into a first oil temperature range a representing the lowest level, a second oil temperature range b representing a relatively low level, and a third oil temperature range c representing a normal level. The calculating portion 9p executes an alarm control process for making the alarm lamp 14 light up continuously when the detected oil temperature is in the first oil temperature range a, making the alarm lamp 14 blink when it is in the second oil temperature range b, and making the alarm lamp 14 turn out when it is in the third oil temperature range c. This enables a front control system for a construction machine to perform front control accurately and safely even when the temperature of hydraulic oil is low.
    Type: Grant
    Filed: June 24, 1997
    Date of Patent: March 30, 1999
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Kazuo Fujishima, Hiroshi Watanabe, Masakazu Haga, Takashi Nakagawa
  • Patent number: 5835874
    Abstract: In a region limiting excavation control system for a construction machine, a region where a front attachment (1A) is movable is set beforehand. A control unit (9) calculates the position and posture of the front attachment based on signals from angle sensors (8a-8c), calculates a target speed vector (Vc) of the front attachment based on signals from control lever units (4a, 4b), and modifies the target speed vector such that the target speed vector is maintained as it is when the front attachment is within the set region but not near the boundary thereof. A vector component (Vcy) of the target speed vector in the direction toward the boundary of the set region is reduced when the front attachment is within the set region near the boundary thereof, and the front attachment is returned to the set region and when the front attachment is outside the set region. As a result, the excavation within a limited region can be implemented efficiently and smoothly.
    Type: Grant
    Filed: December 5, 1995
    Date of Patent: November 10, 1998
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Toichi Hirata, Eiji Yamagata, Hiroshi Watanabe, Masakazu Haga, Kazuo Fujishima, Hiroyuki Adachi
  • Patent number: 5822891
    Abstract: A work area limitation control system for a construction machine which includes a second entrance forbidden area calculating portion which sets a second entrance forbidden area positioned closer to a front device than a first entrance forbidden area. A slowdown control calculating portion calculates distances between two monitoring points and the second and first entrance forbidden areas and modifies operation signals (pilot pressures) depending on the relation of the calculated distances with respect to a slowdown distance.
    Type: Grant
    Filed: December 18, 1996
    Date of Patent: October 20, 1998
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Kazuo Fujishima, Hiroshi Watanabe, Masakazu Haga
  • Patent number: 5752333
    Abstract: An area where a front device 1A is movable is set in advance. A target speed vector of the front device is modified such that its component in the direction toward a boundary of the set area is reduced, by using signals obtained by reducing operation signals input from control lever units 4a-4c when a mode switch 20 is turned on and the front device is within and near the boundary of the set area, and by using the operation signals as they are when the mode switch 20 is turned off. When the front device is outside the set area, the target speed vector is modified so that the front device is returned to the set area. Thus, excavation within a limited area can be performed efficiently and smoothly, and an operator can select one of an accuracy precedence work mode and a speed precedence work mode at his own discretion.
    Type: Grant
    Filed: April 9, 1997
    Date of Patent: May 19, 1998
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Takashi Nakagawa, Hiroshi Watanabe, Masakazu Haga, Kazuo Fujishima, Eiji Egawa
  • Patent number: 5735065
    Abstract: In an area limiting excavation control system for construction machines such as hydraulic excavators, excavation is smoothly and efficiently carried out within a limited area by setting an area beforehand where a front attachment (1A) is movable, calculating the position and posture of the front-attachment (1A) by a control unit (9) based on signals from angle sensors (8a) to (8c), calculating a limit value of the component of the boom-dependent bucket tip speed vertical to the boundary of the set area so that when the front attachment is inside the set area near the boundary thereof, the moving speed of the front attachment in the direction vertical to the boundary of the set area is restricted, and when the front attachment is outside the set area, it is returned to the set area, and modifying a boom operation signal so as to prevent the boom-dependent bucket tip speed from exceeding the limit value.
    Type: Grant
    Filed: June 5, 1996
    Date of Patent: April 7, 1998
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Eiji Yamagata, Kazuo Fujishima, Hiroyuki Adachi, Hiroshi Watanabe, Masakazu Haga
  • Patent number: 5701691
    Abstract: In an excavation area limiting control system for a construction machine for limitingly controlling an area to be excavated, a region where a front device 1A is movable is set beforehand. The position and posture of the front device are calculated based on signals from angle sensors 8a-8c, and a target speed vector of the front device is calculated based on detection signals from control lever units and load pressures detected by pressure sensors 270a to 271b. The target speed vector is modified so that a vector component of the target speed vector in the direction toward the boundary of the set region is reduced when the front device is within the set region near the boundary thereof, and the front device is returned to the set region when the front device is outside the set region. Control signals corresponding to the modified target speed vector are further modified depending on the load pressures and output to proportional solenoid valves 210a to 211b.
    Type: Grant
    Filed: January 31, 1996
    Date of Patent: December 30, 1997
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hiroshi Watanabe, Toichi Hirata, Masakazu Haga, Eiji Yamagata, Kazuo Fujishima, Hiroyuki Adachi
  • 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: 5265569
    Abstract: A rotational speed control system for controlling the number of revolutions of an engine through remote control of rotation of a governor lever. This rotational speed control system includes a stepping motor for rotating the governor lever, lever position sensor switches for detecting abutment of the governor lever against stoppers, respectively, a pulse counter, and a controller. The controller is adapted to store a count value of the pulse counter as a renewable reference value when the position sensor switches are turned on, to carry out the rotational speed control of the engine and necessary preadjustments according the reference value.
    Type: Grant
    Filed: April 16, 1992
    Date of Patent: November 30, 1993
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Masaki Egashira, Masakazu Haga, Osamu Tomikawa, Touichi Hirata
  • Patent number: 5155996
    Abstract: A hydraulic drive system for a construction machine comprising a prime mover (1), a hydraulic pump (2) of variable displacement type driven by the prime mover, at least one hydraulic actuator (6) driven by a hydraulic fluid delivered from the hydraulic pump, control valves connected between the hydraulic pump and the actuator for controlling a flow rate of the hydraulic fluid supplied to the actuator dependent on the operation amount of control apparatus, pump control apparatus for controlling a displacement volume of the hydraulic pump dependent on the operation amount of the control apparatus such that the delivery rate of the hydraulic pump is increased with an increase in the operation amount, and prime mover control apparatus (29) for controlling a revolution speed of the prime mover.
    Type: Grant
    Filed: August 20, 1990
    Date of Patent: October 20, 1992
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Akira Tatsumi, Toichi Hirata, Masakazu Haga, Eiki Izumi
  • Patent number: 5074194
    Abstract: In a hydraulic machine such as, for example, a hydraulic excavator equipped with hydraulic actuators, a hydraulic driving method and a hydraulic driving apparatus enable all the hydraulic actuators to be operated according to normal operational-speed characteristics (first mode). The method and the apparatus alter the operational-speed characteristics of at least one of the hydraulic actuators, according to other characteristics (second mode), in accordance with working contents. The actuators altered in this manner can be operated according to the operational-speed characteristics of the second mode, without exerting an influence upon the operational-speed characteristics of the remaining hydraulic actuators.
    Type: Grant
    Filed: October 27, 1989
    Date of Patent: December 24, 1991
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Toichi Hirata, Kuniaki Yoshida, Hideaki Tanaka, Genroku Sugiyama, Masakazu Haga
  • Patent number: 5062350
    Abstract: A hydraulic drive system for a civil engineering and construction machine of the present invention comprises a hydraulic pump (11, 11A), a plurality of actuators (4-6) driven by a hydraulic fluid supplied from the hydraulic pump and including an arm cylinder (5) and a boom cylinder (4), a plurality of flow control valves (12, 14, 16) for controlling flows of the hydraulic fluid supplied to the respective actuators and including an arm directional control valve (14) and a boom directional control valve (12) and a plurality of distribution compensating valves (13, 15, 17; 13A, 15A, 17A) for controlling differential pressures across the respective flow control valves, the distribution compensating valves each having a first device (13d,15d, 17d; 13e, 13f, 15e, 15f, 17e, 17f) to set a target value of the differential pressure across the associated flow control valve.
    Type: Grant
    Filed: July 12, 1990
    Date of Patent: November 5, 1991
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hideaki Tanaka, Toichi Hirata, Genroku Sugiyama, Masakazu Haga, Yusuke Kajita