Patents by Inventor Tomomasa Nishikawa

Tomomasa Nishikawa 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).

  • Publication number: 20150022125
    Abstract: An electric tool for driving a tip tool, the electric tool includes: a removable battery; the brushless motor configured to generate a driving force for driving the tip tool; an inverter circuit configured to supply drive power from the removable battery to the brushless motor using a plurality of semiconductor switching elements; a controller configured to control the inverter circuit to control rotation of the brushless motor; a temperature detector configured to detect a temperature of the brushless motor or the semiconductor switching elements; and a voltage detector configured to detect a voltage of the battery. The brushless motor is driven such that a duty ratio of PWM drive signal for driving the semiconductor switching elements is determined based on relationship between the temperature detected by the temperature detector and the voltage detected by the voltage detector.
    Type: Application
    Filed: March 13, 2013
    Publication date: January 22, 2015
    Inventors: Nobuhiro Takano, Tetsuhiro Harada, Yoshio Iimura, Tomomasa Nishikawa, Hiroki Uchida, Yoshihiro Nakano
  • Patent number: 8925645
    Abstract: An oil pulse tool includes a motor, an oil pulse unit, an output shaft on which a front end tool is attached, a torque detecting sensor for detecting generation of an impact torque, and an operating portion configured to detect a time period between a first impact torque detected by the torque detecting sensor and a second impact torque detected by the torque detecting sensor. The second impact torque is smaller than the first impact torque. The operating portion carries out a notification when the time period between the first impact torque and the second impact torque is less than a predetermined evaluation value for the time period between the first impact torque and the second impact torque.
    Type: Grant
    Filed: May 8, 2009
    Date of Patent: January 6, 2015
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Tetsuhiro Harada, Tomomasa Nishikawa, Kazutaka Iwata, Shinki Ohtsu, Nobuhiro Takano
  • Publication number: 20140374130
    Abstract: An impact tool includes a motor, a hammer, an anvil, and a control unit. The hammer is configured to be driven by the motor and be movable in an axial direction of the motor. The anvil is configured to be struck by the hammer. The control unit is configured to control a rotation of the motor. The impact tool further includes a restricting unit configured to restrict the movement of the hammer in the axial direction. The control unit is configured to select a driving mode of the motor between a first mode and a second mode. The control unit selects the first mode when a load of the motor is less than or equal to a prescribed value regardless of a restriction of the restricting unit, whereas the control unit selects the second mode when the load exceeds the prescribe value and the restricting unit restricts the movement of the hammer.
    Type: Application
    Filed: March 4, 2013
    Publication date: December 25, 2014
    Inventors: Mizuho Nakamura, Nobuhiro Takano, Tomomasa Nishikawa, Hironori Mashiko
  • Publication number: 20140248519
    Abstract: A battery pack that can ensure a sealing property of a housing case and can cool the inside of the housing case is provided. A battery pack has: a housing case that houses a battery cell(s) and can be attached to and detached from a tool main body; an insulating covering material that covers the battery cell in a state in which electrodes of the battery cell are exposed; a holder that retains the battery cell covered with the covering material in the housing case; and an opening portion that is provided in the holder and exposes a part of the battery cell covered with the covering material to a passage of air that flows in the housing case.
    Type: Application
    Filed: February 6, 2014
    Publication date: September 4, 2014
    Applicant: HITACHI KOKI CO., LTD.
    Inventors: Tomomasa NISHIKAWA, Tetsuhiro HARADA
  • Publication number: 20140209341
    Abstract: A power tool (1) and a method of producing such power tool capable of improving dust proof performance with respect to a circuit board (33) and a stator coil (31B), and capable of securing cooling performance to the circuit board. The power tool includes a brushless motor (3) having a hollow stator (31), a rotor (32) positioned in an internal space of the stator, and a motor driver circuit connected to the stator. The stator includes a coil (31B) electrically connected to the mo- for driver circuit. The coil is coated with a coating agent (31D), and the motor driver circuit is covered with an insulation cover member (33D).
    Type: Application
    Filed: August 10, 2012
    Publication date: July 31, 2014
    Applicant: Hitachi Koki Co., Ltd.
    Inventors: Tomomasa Nishikawa, Tetsuhiro Harada, Hiroki Uchida, Yoshihiro Nakano, Hiroki Tsunoda, Katsuaki Sukegawa, Kazuhiko Morita
  • Publication number: 20140209338
    Abstract: A power tool includes: a motor; a fan driven by the motor and defining an axis and a radial direction; and a housing for accommodating the motor and the fan therein, the housing including: a peripheral wall formed with a ventilation hole; and a grid partly covering the ventilation hole, the ventilation hole being positioned adjacent to the fan and having a shape defined by a circumferential surface, the grid including at least one elongated portion extending in a longitudinal direction perpendicular to the radial direction, and a distance from the axis of the fan to the circumferential surface is different from a distance from the axis of the fan to one elongated portion in the radial direction of the fan.
    Type: Application
    Filed: August 13, 2012
    Publication date: July 31, 2014
    Inventors: Tetsuhiro Harada, Tomomasa Nishikawa, Yoshihiro Nakano, Hiroki Uchida
  • Publication number: 20140125159
    Abstract: A power tool capable of preventing entrance of foreign matter or water etc. through the air hole as much as possible is provided. To prevent foreign matter from entering a housing 2 through a outlet 22, a first through hole 70b penetrating a main wall 71 is formed on a part of the main wall 71 of a cover 70 covering the outlet 22, second through holes 70c are formed on: a part closest to a front end portion of the cover 70; an end portion in the extending direction of the handle of the cover 70; and an end portion in the opposite direction to the extending direction of the handle of the cover 70.
    Type: Application
    Filed: August 15, 2012
    Publication date: May 8, 2014
    Applicant: HITACHI KOKI CO., LTD.
    Inventors: Yutaka Ito, Tomomasa Nishikawa, Tetsuhiro Harada, Yoshihiro Nakano, Hiroki Uchida, Tomoyuki Hoshi
  • Publication number: 20140069672
    Abstract: A power tool includes: a motor configured to be driven based on one of a plurality of drive modes; a mode section switch; a control portion. The control portion is configured to operate responsive to a first operation to assign one or more drive modes preselected from the plurality of drive modes to the mode selection switch. A second operation different from the first operation is capable of manipulating the mode selection switch to select one drive mode from the one or more preselected drive modes, the control portion being further configured to control the motor based on the one drive mode selected by the mode selection switch.
    Type: Application
    Filed: March 21, 2012
    Publication date: March 13, 2014
    Applicant: Hitachi Koki Co., Ltd.
    Inventors: Hironori Mashiko, Nobuhiro Takano, Tomomasa Nishikawa, Atsushi Nakagawa, Masanori Watanabe, Mizuho Nakamura, Katsuhiro Oomori
  • Publication number: 20140050600
    Abstract: A brushless motor is incorporated in one of divided constituent members of a motor casing which is disassembled, and then, the divided constituent members of the motor casing which is disassembled are connected to each other into the motor casing assembled with machine screws screwed into machine screw holes. As this occurs, when a wiring of the brushless motor is held by a first stationary blade portion and a second stationary blade portion, the wiring is allowed to lead to an outside of an outer cylindrical portion through a gap defined between the first stationary blade portion and the second stationary blade portion.
    Type: Application
    Filed: August 15, 2013
    Publication date: February 20, 2014
    Applicant: HITACHI KOKI CO., LTD.
    Inventors: Seiichi Kodato, Mizuho Nakamura, Tomomasa Nishikawa, Kouji Sagawa
  • Publication number: 20140049204
    Abstract: An electric working machine including: an input part; a control unit configured to control a motor in accordance with an operation amount of the input part; and a switching part; wherein, when a predetermined operation is performed to the switching part, the control unit shifts to a fixed control mode in which the motor is controlled in accordance with an operation amount of the input part at the time when the predetermined operation is performed to the switching part, irrespective of an operation amount of the input part after the predetermined operation is performed to the switching part.
    Type: Application
    Filed: August 15, 2013
    Publication date: February 20, 2014
    Applicant: HITACHI KOKI CO., LTD.
    Inventors: Tatsuya Ito, Mizuho Nakamura, Yoshio Iimura, Tomomasa Nishikawa
  • Patent number: 8640789
    Abstract: According to an aspect of the invention, an oil pulse tool includes: a motor generating a driving force according to a driving voltage; an oil pulse unit driven by the driving force and generating a torque in a pulse-like shape when the motor passes a strike position on a shaft thereof; and an output shaft on which a front end tool is mounted, the output shaft being connected to the shaft, characterized in that the oil pulse tool further comprises driving adjusting means to control the driving voltage, the driving voltage is reduced during a given period including a timing when the torque is transmitted to the output shaft, and the reduced driving voltage is increased when the given period is finished.
    Type: Grant
    Filed: May 8, 2009
    Date of Patent: February 4, 2014
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Tetsuhiro Harada, Tomomasa Nishikawa, Kazutaka Iwata, Shiniki Otsu, Nobuhiro Takano
  • Publication number: 20140014384
    Abstract: A power tool includes a small-size lithium ion secondary battery used as its driving source, and at least one lithium ion secondary battery having a diameter of 14 mm is disposed inside a grip portion of a main body of the power tool. The lithium ion secondary battery has a sufficient output characteristic required for driving the power tool. When a switch installed in the main body of the power tool is operated by a user, electric power is supplied to a driving unit including a motor so that the power tool is activated. The lithium ion secondary battery is of a pack type, or is directly housed inside the grip portion, and the grip portion, which houses three of the lithium ion secondary batteries, is designed to have a diameter of 51.8 mm or less.
    Type: Application
    Filed: July 9, 2013
    Publication date: January 16, 2014
    Inventors: Yuki HORIE, Tomomasa NISHIKAWA, Takao ARADACHI, Kazuhiko FUNABASHI
  • Publication number: 20130333910
    Abstract: According to one embodiment, an impact tool includes: a motor; and a hammer that is connected to the motor and that has a striking-side surface; and an anvil that is journalled to be rotatable with respect to the hammer, that has a struck-side surface and that provides a striking power to a tip tool, wherein the motor is drivable in: a first driving mode in which the motor is continuously driven in a normal rotation; a second driving mode in which the motor is intermittently driven only in the normal rotation; and a third driving mode in which the motor is intermittently driven in the normal rotation and in a reverse rotation.
    Type: Application
    Filed: July 29, 2010
    Publication date: December 19, 2013
    Applicant: HITACHI KOKI CO., LTD.,
    Inventors: Hideyuki Tanimoto, Nobuhiro Takano, Tomomasa Nishikawa, Kazutaka Iwata, Hironori Mashiko, Hayato Yamaguchi, Atsushi Nakagawa, Katsuhiro Oomori, Mizuho Nakamura, Hiroki Uchida, Saroma Nakano
  • Publication number: 20130291810
    Abstract: An engine-operated device includes a dust separating device. An air inlet provided on a first end side of the dust separating device. A first discharge opening is provided in the lateral surface on a second end side of the longitudinal direction, and a second discharge opening is provided to be separated from the first discharge opening. A first connecting passage is connected between the first discharge opening and the rotor cover of a magneto-rotor, and a second connecting passage is connected between an upstream side of an air cleaner case and the second discharge opening.
    Type: Application
    Filed: December 27, 2011
    Publication date: November 7, 2013
    Applicant: HITACHI KOKI CO., LTD.
    Inventors: Tomomasa Nishikawa, Fumikazu Hirasawa
  • Publication number: 20130284480
    Abstract: In a power tool including: a housing having a body portion which houses a motor and a handle portion extending downward from the body portion; an output portion driven at the front of the motor; and a trigger switch which controls power supply from a battery to the motor, the motor, the battery, and the trigger switch are arranged so as to overlap each other in an intersecting direction with respect to a front-and-rear direction.
    Type: Application
    Filed: April 30, 2013
    Publication date: October 31, 2013
    Applicant: HITACHI KOKI CO., LTD.
    Inventors: Yuki HORIE, Nobuhiro TAKANO, Kazuhiko FUNABASHI, Tomomasa NISHIKAWA, Yukihiro SHIMA, Takao ARADACHI
  • Publication number: 20130264087
    Abstract: A driving tool includes a motor, and an end-bit holding section. The motor includes an output shaft. The end-bit holding section is connected to and rotated by the motor and configured to hold an end-bit. The driving tool further includes a weight connected to the motor without a reduction mechanism and rotatable together with the motor and the end-bit holding section.
    Type: Application
    Filed: December 28, 2011
    Publication date: October 10, 2013
    Applicant: Hitachi Koki Co., Ltd.
    Inventors: Tetsuhiro Harada, Nobuhiro Takano, Tomomasa Nishikawa, Hironori Mashiko
  • Publication number: 20130255982
    Abstract: A power tool, in which a case that is connected to a housing and the case houses a reducer mechanism that decelerates an output of an electric motor and an impact mechanism that transmits an output of the reducer mechanism to a tip tool, is provided. The power tool further includes an inner cover that covers an opening of the case, a ring gear included in the reducer mechanism, a spindle that is rotatably supported by a bearing, and a space portion that is placed between the inner cover and the ring gear and in a periphery of the bearing, and capable of stocking grease. A through hole, which communicates with the inside and outside of the case through the space portion, is formed in the inner cover.
    Type: Application
    Filed: February 15, 2013
    Publication date: October 3, 2013
    Applicant: HITACHI KOKI CO., LTD.
    Inventors: Shigeru Takahashi, Katsuhiro Oomori, Tomomasa Nishikawa
  • Publication number: 20130245789
    Abstract: An electric tool includes a motor, a light having a function in addition to a data transmission, a switch configured to switch power supply to the light in accordance with a user operation; and a control unit. Upon a switch is switched from OFF to ON, the light is blinked at a frequency above the human-sensible range on the basis of data such as the usage history data of the electric tool. An average of the blinking frequency of the light is approximately 4,800 Hz when a bit rate is set to 9,600 bps, for example. Further, an average of a duty ratio of a drive signal of the light during blinking is approximately 50%.
    Type: Application
    Filed: February 6, 2013
    Publication date: September 19, 2013
    Applicant: HITACHI KOKI CO., LTD.
    Inventors: Yoshio Iimura, Hironori Mashiko, Tomomasa Nishikawa, Tatsuya Ito
  • Patent number: 8529169
    Abstract: According to the invention, a drilling tool includes: a motor; a transmission drive unit for transmitting a rotation force of the motor to rotate a drill bit; and a dust collector for collecting dust produced from a workpiece drilled by the drill bit, wherein the dust collector is provided with a pierced portion pierced by the drill bit, a dust collection port for sucking the produced dust and its surrounding air, and a blowoff port for blowing air against a vicinity of the piercing drill bit.
    Type: Grant
    Filed: December 5, 2008
    Date of Patent: September 10, 2013
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Tomomasa Nishikawa, Kenji Kobori, Tsukasa Suzuura
  • Patent number: 8522519
    Abstract: A lawn mower comprising: a power supply; a chassis for holding the power supply; a fixed shaft attached to the chassis; a rotary blade which is rotatably supported with respect to the fixed shaft; a transmitting portion which transmits rotation of the power supply to the rotary blade; and a fixed blade which is coaxially-arranged with the rotary blade, wherein a distance between the rotary blade and the fixed blade can be varied.
    Type: Grant
    Filed: September 15, 2011
    Date of Patent: September 3, 2013
    Assignee: Hitachi Koko Co., Ltd.
    Inventors: Kenji Kobori, Hiroto Inagawa, Tomomasa Nishikawa