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).

  • Patent number: 11052530
    Abstract: Provided is an electric work machine that can suppress a temperature increase of a component controlling an electric motor. The electric work machine including a brushless motor that operates a tip tool includes a rectification circuit that converts a voltage to be applied to the brushless motor from an alternating current voltage to a direct current voltage, and a switching circuit that controls the brushless motor, and the rectification circuit is arranged upstream of the switching circuit in a circulation path of the air that cools the rectification circuit and the switching circuit.
    Type: Grant
    Filed: September 29, 2015
    Date of Patent: July 6, 2021
    Assignee: KOKI HOLDINGS CO., LTD.
    Inventors: Akira Matsushita, Tomomasa Nishikawa, Yuta Noguchi, Kuniaki Kanbe, Shingo Yamazaki
  • Patent number: 10994393
    Abstract: To provide a rotary impact tool capable of: suppressing a rise in temperature in a motor or switching elements and a current flowing in the motor or switching elements while suppressing a degradation in tightening performance; and improving operability. The rotary impact tool includes: a motor; an end-bit holding part driven by the motor; an impact mechanism provided on a drive transmission path from the motor to the end-bit holding part and configured to intermittently produce rotary impacts, the rotary impacts transmitting a drive force of the motor to the end-bit holding part; a switching element configured to change a voltage supplied to the motor; and a control unit controlling the switching element. The control unit is configured such that the voltage supplied to the motor begins to gradually rise within a period of time from a timing when a first rotary impact ends to a timing when a second rotary impact subsequent to the first rotary impact starts.
    Type: Grant
    Filed: January 6, 2017
    Date of Patent: May 4, 2021
    Assignee: Koki Holdings Co., Ltd.
    Inventors: Tetsuhiro Harada, Tomomasa Nishikawa, Tatsuya Ito, Takahiro Hirai, Yang Li
  • Patent number: 10991228
    Abstract: A technique capable of immediately reporting to an operator an occurrence of abnormality in an electric tool is provided. A communication terminal includes a communication-terminal-side control unit that determines whether abnormality has occurred in any of electric tools based on information acquired from the electric tools via wireless communication. When the communication-terminal-side control unit determines the occurrence of abnormality in any one of the electric tools, the occurrence of abnormality in the electric tool is reported by at least one of a report unit included in the electric tools other than the electric tool in which the occurrence of abnormality is determined and a report unit included in the communication terminal.
    Type: Grant
    Filed: April 15, 2019
    Date of Patent: April 27, 2021
    Assignee: KOKI HOLDINGS CO., LTD.
    Inventors: Tomomasa Nishikawa, Takuya Konnai, Tatsuya Ito
  • Patent number: 10888938
    Abstract: To provide a cutting machine that suppresses swinging of the cutting portion when the battery pack is attached or detached, the cutting machine includes a cutting portion, a base, and a swing support mechanism. The cutting portion includes: a motor, a motor housing accommodating the motor, an output shaft configured to be rotated upon rotation of the motor, a battery pack serving as a power source of the motor, and a battery pack attaching portion including a pair of rail portions with which the battery pack is engageable, where a cutting blade is configured to be detachably attached to the output shaft. The base has a contact surface on which a workpiece is configured to be placed. The swing support mechanism is connected to the base and the cutting portion and includes a swing shaft extending in parallel to the output shaft.
    Type: Grant
    Filed: May 9, 2019
    Date of Patent: January 12, 2021
    Assignee: Koki Holdings Co., Ltd.
    Inventor: Tomomasa Nishikawa
  • Publication number: 20200403544
    Abstract: In the work device that has a self-holding circuit (61) maintaining power supply from a power supply circuit (12) by output from a microcomputer (40) and has a structure in which stopping output to the self-holding circuit (61) causes interruption of power supply from the power supply circuit (12) to the microcomputer (40), the firmware of the microcomputer (40) is made to be rewritable and a power holding unit (condenser (C1)) for temporarily continuing power supply to the microcomputer (40) is provided, thereby realizing a so-called “off-delay timer function” for restarting the microcomputer (40). This configuration enables maintenance of power to the microcomputer (40) after update of the firmware even in a work device that cannot be restarted once power has been turned off unless trigger operation is performed, thereby enabling automatic restart of the microcomputer 40 after resetting is enabled.
    Type: Application
    Filed: February 22, 2019
    Publication date: December 24, 2020
    Applicant: Koki Holdings Co., Ltd.
    Inventors: Yuki ISHIKAWA, Hayato Yamaguchi, Tomomasa NISHIKAWA, Masashi TAKEHISA, Tatsuya ITO
  • Patent number: 10836019
    Abstract: In order to provide an impact work machine capable of preventing oil leakage and cooling a power transmission apparatus, an impact work machine transmitting power of an electric motor 16 including an output shaft extending in an axis A1 direction to an anvil includes: a housing including a motor case accommodating the electric motor, and a grip extending from the motor case; a speed reducer and an impact mechanism 96 each transmitting power of the electric motor to the anvil; a hammer case located forward of the motor case and nonrotatable relative to the motor case; an extension portion provided on the housing and extending from the motor case toward the hammer case so as to cover at least part of the hammer case; and a passage provided between the hammer case and the extension portion and through which air passes.
    Type: Grant
    Filed: January 8, 2016
    Date of Patent: November 17, 2020
    Assignee: KOKI HOLDINGS CO., LTD.
    Inventors: Akira Matsushita, Takuhiro Murakami, Tomomasa Nishikawa, Junichi Toukairin, Shota Takeuchi
  • Publication number: 20200212505
    Abstract: A battery pack includes cell units in which upper and lower battery cells are connected in series, wherein an output of series-connection and an output of parallel-connection can be switched. The cell units are respectively provided with protection circuit ICs for monitoring the state of the battery cells, and only the protection circuit on the lower cell unit side is provided with a controller 350 including a microcomputer. To adjust the power consumption for the microcomputer only provided in the lower cell unit, the circuit on the upper cell unit side is provided with a current consumption control means including dummy loads. The current consumption control means is operated in conjunction with the start-up of the microcomputer in the controller so as to equalize power consumption on the upper cell unit side and the lower cell unit side.
    Type: Application
    Filed: May 30, 2018
    Publication date: July 2, 2020
    Applicant: Koki Holdings Co., Ltd.
    Inventors: Yasushi Nakano, Satoshi YAMAGUCHI, Hiroyuki HANAWA, Kazuhiko FUNABASHI, Tomomasa NISHIKAWA, Shota KANNO, Toshio Mizoguchi, Takuya Teranishi
  • Publication number: 20200180044
    Abstract: The electrical device comprises a common device main body having selectively and detachably attached thereto either a variable-voltage power supply device or a high-voltage power supply device. The device main body has: a protruding section that abuts a power supply-side main erroneous attachment prevention section provided in the variable-voltage power supply device and the high-voltage power supply device; a device-side main erroneous attachment prevention section that abuts the power supply-side main erroneous attachment prevention section provided in a low-voltage power supply device and prevents the low-voltage power supply device from abutting an attachment positioning section; and a device-side attachment pet' lifting section that can be combined in a power supply-side auxiliary erroneous attachment prevention section provided in the high-voltage power supply device.
    Type: Application
    Filed: July 27, 2018
    Publication date: June 11, 2020
    Applicant: Koki Holdings Co., Ltd.
    Inventors: Yusuke FUNABIKI, Tomomasa NISHIKAWA, Takuya Teranishi, Masayuki Ogura
  • Patent number: 10661427
    Abstract: A power tool has a fan guide for straightening the flow of cooling air generated by a fan, wherein the branching passages through are provided for causing a portion of the cooling air drawn into the fan from a ventilation hole to diverge from a flow toward an exhaust port formed on a bearing guide side, and the portion of the cooling air flows toward an inlet and thereby circulates inside a housing. The branching passages through provided to the fan guide are formed so as to be inclined in the same direction as a circumferential direction so that air path resistance during actual operation (in an intermediate-speed region) does not increase.
    Type: Grant
    Filed: January 27, 2017
    Date of Patent: May 26, 2020
    Assignee: Koki Holdings Co., Ltd.
    Inventors: Akira Matsushita, Tomomasa Nishikawa, Noriyuki Horie, Masahiro Fujiwara
  • Publication number: 20200161609
    Abstract: The electrical apparatus, in which a series connection state and a parallel connection state of an upper cell unit including five battery cells and a lower cell unit can be automatically switched by means of a difference in a terminal shape on the electrical apparatus body side, has a terminal holder and holds apparatus side terminals. The terminal holder, which establishes an electrically connected state with the connection terminals of the battery pack, is provided with two parallel protruding parts that extend in the forward-backward direction, and second rail grooves fitted to the protruding parts on the electrical apparatus side. Due to the fitting, relative movement of the terminal holder and the battery pack in the vertical direction can be suppressed, and wear on the apparatus side terminals can be greatly suppressed.
    Type: Application
    Filed: June 29, 2018
    Publication date: May 21, 2020
    Applicant: Koki Holdings Co., Ltd.
    Inventors: Takuhiro Murakami, Tomomasa NISHIKAWA, Shinji Watanabe, Junpei SATO, Hikaru Tamura, Shota KANNO, Toshio Mizoguchi, Yasushi Nakano, Hiroyuki HANAWA, Kazuhiko FUNABASHI, Masayuki Ogura, Takuya Teranishi, Junichi Toukairin, Shota Takeuchi, Yusuke FUNABIKI
  • Publication number: 20200127339
    Abstract: A battery pack which has cell units in which top-side and bottom-side battery cells are connected in series, and is capable of switching the connection state of the cell units, wherein a control unit monitors voltage imbalances between the cell units, and also monitors whether or not a cell unit contact failure has occurred. In order to stop a charging/discharging when a contact failure occurs, a signal (abnormality stoppage signal or charging stoppage signal) for stopping discharge is produced and outputted to the electrical device body-side.
    Type: Application
    Filed: July 24, 2018
    Publication date: April 23, 2020
    Applicant: Koki Holdings Co., Ltd.
    Inventors: Yasushi Nakano, Satoshi YAMAGUCHI, Hiroyuki HANAWA, Kazuhiko FUNABASHI, Tomomasa NISHIKAWA, Shota KANNO, Toshio Mizoguchi
  • Patent number: 10562107
    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: Grant
    Filed: August 13, 2012
    Date of Patent: February 18, 2020
    Assignee: Koki Holdings Co., Ltd.
    Inventors: Tetsuhiro Harada, Tomomasa Nishikawa, Yoshihiro Nakano, Hiroki Uchida
  • Publication number: 20200052559
    Abstract: Providing an electric tool with excellent cooling efficiency. An electric tool includes: a housing 2; a motor 3; a fan 34; a sensing portion 41; a switching portion 42; and a circuit board 40. The motor 3 is accommodated in the housing 2. The motor 3 includes a stator 33, a rotor 32, and a rotating shaft 31. The rotor 32 is rotatable relative to the stator 33. The rotating shaft 31 is rotatable together with the rotor 32. The fan 34 is configured to generate a cooling air flow inside the housing 2. The sensing portion 41 is configured to detect a rotated position of the rotor 32. The switching portion 41 controls a rotation of the rotor 32. The sensing portion 41 and the switching portion 42 are mounted on the circuit board 40.
    Type: Application
    Filed: February 23, 2018
    Publication date: February 13, 2020
    Applicant: KOKI HOLDINGS CO., LTD.
    Inventors: Akira MATSUSHITA, Tomomasa NISHIKAWA, Yuta NOGUCHI, Takahiro HIRAI
  • Patent number: 10442066
    Abstract: In order to provide a driver for reducing reaction generated to a driver main body, the driver 1 includes a nose portion 3 provided in a housing 2 and extending in a longitudinal direction, the nose portion being configured to allow a fastener to pass therethrough, a plunger 7 configured to move in an impact direction parallel to the longitudinal direction to impact the fastener through the nose portion, a weight 8, and a coil spring 9 configured to be compressed by a motor 5 in the longitudinal direction. a release of the compression causing the plunger 7 to move in the impact direction, while causing the weight 8 to move in a counter-impact direction which is away from the plunger 7. The coil spring 9 is provided between the plunger 7 and the weight 8. The coil spring has one end portion urging the plunger 7, and another end portion urging the weight 8.
    Type: Grant
    Filed: August 21, 2015
    Date of Patent: October 15, 2019
    Assignee: Koki Holdings Co., Ltd.
    Inventors: Tomomasa Nishikawa, Yoshiichi Komazaki, Tetsuhiro Harada, Norikazu Baba
  • Publication number: 20190262916
    Abstract: To provide a cutting machine that suppresses swinging of the cutting portion when the battery pack is attached or detached, the cutting machine includes a cutting portion, a base, and a swing support mechanism. The cutting portion includes: a motor, a motor housing accommodating the motor, an output shaft configured to be rotated upon rotation of the motor, a battery pack serving as a power source of the motor, and a battery pack attaching portion including a pair of rail portions with which the battery pack is engageable, where a cutting blade is configured to be detachably attached to the output shaft. The base has a contact surface on which a workpiece is configured to be placed. The swing support mechanism is connected to the base and the cutting portion and includes a swing shaft extending in parallel to the output shaft.
    Type: Application
    Filed: May 9, 2019
    Publication date: August 29, 2019
    Inventor: Tomomasa Nishikawa
  • Publication number: 20190260209
    Abstract: In order that the output voltage of a battery pack can be switched and the battery pack can be shared among different voltage electric appliances, this battery pack has a switching mechanism that switches outputting a low voltage by parallel connection of two cell units or outputting a high voltage by series connection of the two cell units, said two cell units each being composed of a plurality of cells connected in series, wherein the switching mechanism is configured from a change-over switch having an operation lever (452). The change-over switch is embedded in a battery pack (400), and an operator is able to manually switch outputting 18 V by setting the operation lever (452) at a first position or outputting 36 V by setting the operation lever (452) at a second position.
    Type: Application
    Filed: October 27, 2017
    Publication date: August 22, 2019
    Applicant: Koki Holdings Co., Ltd.
    Inventors: Tomomasa NISHIKAWA, Masayuki OGURA, Masaru HIRANO, Takuhiro MURAKAMI, Nobuhiro TAKANO, Osamu KAWANOBE, Akira MATSUSHITA, Hayato YAMAGUCHI
  • Publication number: 20190259984
    Abstract: A battery pack houses first and second cell units that are composed of a plurality of cells, and has a positive electrode power source terminal and a negative electrode power source terminal. This battery pack is provided with a series connector capable of connecting, in series, the first and second cell units and a parallel connector capable of connecting, in parallel, the first and second cell units, and is capable of switching between a parallel connection voltage and a series connection voltage. In the case of attachment to the high voltage electrical device body, the series connector becomes conductive and the parallel connector pair is cut off by the action of the series/parallel switching terminal. In the case of attachment to a low voltage electrical device body, the state is returned to an initial state, the series connector is cut off, and the parallel connector pair becomes conductive.
    Type: Application
    Filed: October 27, 2017
    Publication date: August 22, 2019
    Applicant: Koki Holdings Co., Ltd.
    Inventors: Tomomasa NISHIKAWA, Takuya Teranishi, Naoto Wakatabe, Akira Matsushita, Masaru Hirano, Osamu Kawanobe, Nobuhiro TAKANO, Shinji Watanabe, Hiroyuki HANAWA, Takuhiro Murakami, SHOTA KANNO, Junpei Sato, Hikaru Tamura, Hayato Yamaguchi, Toshio Mizoguchi, Yasushi Nakano, Kazuhiko FUNABASHI, Masayuki Ogura, Yusuke FUNABIKI, Junichi Toukairin, Shota Takeuchi
  • Publication number: 20190259985
    Abstract: In an upper cell unit (2146) and a lower cell unit (2147) comprising five battery cells, positive electrode terminals (2162, 2172) are set apart and aligned vertically, and negative electrode terminals (2167, 2177) are set apart and aligned vertically. When an electrical device body is rated at 36V, device-side terminals are in contact only at the upper terminals (2162, 2167), and short circuiting of the lower terminals (2172, 2177) is effected using a short bar 2059. When the electrical device body is rated at 18V, the upper and lower terminals (2162 and 2172, 2167 and 2177) are simultaneously made to contact the device-side terminals, and the upper cell unit (2146) and the lower cell unit (2147) assume a parallel connected state. Thus, it is possible to automatically switch the output voltage when a battery pack is mounted according to the difference in terminal shape on the electrical device body side.
    Type: Application
    Filed: October 27, 2017
    Publication date: August 22, 2019
    Applicant: Koki Holdings Co., Ltd.
    Inventors: Hiroyuki HANAWA, Tomomasa NISHIKAWA, SHOTA KANNO, Toshio Mizoguchi, Yasushi Nakano, Kazuhiko FUNABASHI, Takuya Teranishi, Naoto Wakatabe, Shinji Watanabe, Junpei Sato, Hikaru Tamura, Nobuhiro TAKANO, Osamu Kawanobe, Hayato Yamaguchi, Akira Matsushita, Masaru Hirano, Takuhiro Murakami, Masayuki Ogura, Yusuke Funabiki, Junichi Toukairin, Shota Takeuchi
  • Patent number: 10377022
    Abstract: A power tool which has an anvil 20 that is rotated by a hammer 22 and is housed in a housing, and rotates an output shaft 18 is provided. The anvil 20 and the output shaft 18 are integrally formed into one unit, and a carrier 33 that is rotatable relative to the anvil 20 by a predetermined angle on the same axis is provided. On one portion of an outer circumferential surface of the anvil 20, a relief surface 20a is formed. Cut-out portions 33b are formed at positions opposed to each other of a carrier 33, and by allowing an engaging pin 37 to be interposed therein, a locking mechanism that limits the relative rotation between the anvil 20 and a lock ring 38 is prepared. When the tool main body is manually rotated while the hammer 22 is being stopped, the engaging pin 37 limits the relative rotation between the anvil 20 and the lock ring 38. The locked state between the anvil 20 and the lock ring 38 is released immediately when the rotation of the motor 4 is started.
    Type: Grant
    Filed: April 23, 2013
    Date of Patent: August 13, 2019
    Assignee: KOKI HOLDINGS CO., LTD.
    Inventors: Keita Saitou, Shinichirou Satou, Tomomasa Nishikawa, Masanori Watanabe, Takuya Teranishi
  • Publication number: 20190244509
    Abstract: A technique capable of immediately reporting to an operator an occurrence of abnormality in an electric tool is provided. A communication terminal includes a communication-terminal-side control unit that determines whether abnormality has occurred in any of electric tools based on information acquired from the electric tools via wireless communication. When the communication-terminal-side control unit determines the occurrence of abnormality in any one of the electric tools, the occurrence of abnormality in the electric tool is reported by at least one of a report unit included in the electric tools other than the electric tool in which the occurrence of abnormality is determined and a report unit included in the communication terminal.
    Type: Application
    Filed: April 15, 2019
    Publication date: August 8, 2019
    Inventors: Tomomasa NISHIKAWA, Takuya KONNAI, Tatsuya ITO