Patents by Inventor Hirokatsu Yamamoto

Hirokatsu Yamamoto 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: 20180297179
    Abstract: A rotary impact tool in one aspect of the present disclosure includes a motor, an impact mechanism, an impact detector, and a controller. The controller executes constant duty ratio control from when the motor is started until an impact is detected by the impact detector. The controller executes constant rotation speed control in response to detection of an impact by the impact detector.
    Type: Application
    Filed: April 9, 2018
    Publication date: October 18, 2018
    Applicant: MAKITA CORPORATION
    Inventors: Takaaki OSADA, Hirokatsu YAMAMOTO, Goshi ISHIKAWA, Kunihisa SHIMA
  • Publication number: 20180272511
    Abstract: An impact fastening tool may include a motor; a hammer configured to be rotationally driven by the motor; an anvil configured to he hit in a rotational direction by the hammer; a signal obtainer configured to obtain a variable signal. which varies in accordance with a hit to the anvil by the hammer; and a seating determiner configured to determine whether or not a fastener has been seated based on the variable signal obtained by the signal obtainer, wherein the seating determiner is configured to determine whether or not the fastener has been seated based on a signal component of the variable signal obtained by the signal obtainer, the signal component corresponding to a predetermined reference frequency.
    Type: Application
    Filed: March 22, 2018
    Publication date: September 27, 2018
    Applicant: MAKITA CORPORATION
    Inventors: Masahiko SAKO, Takaaki OSADA, Hirokatsu YAMAMOTO
  • Publication number: 20180202178
    Abstract: A rebar tying device is configured to tie a plurality of rebars by a wire. The rebar tying device includes a feeder configured to feed the wire wound around a reel by a rotation of a feeding motor; a guide configured to guide the wire fed by the feeder to around the plurality of rebars; a cutter configured to cut the wire fed by the feeder at a predetermined position; a twister configured to twist the wire around the plurality of rebars; a battery configured to supply power to the feeding motor; and a control unit. The control unit configured to control a feeding length of the wire by controlling an energizing time of the feeding motor based on a predetermined feeding length of the wire.
    Type: Application
    Filed: March 11, 2016
    Publication date: July 19, 2018
    Applicant: MAKITA CORPORATION
    Inventors: Kunihisa SHIMA, Hirokatsu YAMAMOTO, Ryo UMEMOTO
  • Publication number: 20180099399
    Abstract: An electric power tool in one aspect of the present disclosure includes a housing; a motor; an output shaft; a rotation transmission; a motor controller; and a twisted-motion detector. The twisted-motion detector is disposed in the housing independently from the motor controller. The twisted-motion detector detects a twisted-motion of the housing in the circumferential direction of the output shaft and outputs a result of the detection to the motor controller.
    Type: Application
    Filed: September 29, 2017
    Publication date: April 12, 2018
    Applicant: MAKITA CORPORATION
    Inventors: Hikaru SUNABE, Hirokatsu YAMAMOTO, Ryo UMEMOTO
  • Publication number: 20180099391
    Abstract: An electric power tool of one aspect of the present disclosure includes a housing, a motor, an output shaft, a first power transmission, a second power transmission, a common sensor, a twisted-motion detector, and a vibration-based load detector. The common sensor detects a motion of the housing and outputs a detection signal indicating the detected motion. The twisted-motion detector detects a twisted-motion of the housing in a circumferential direction of the output shaft based on the detection signal. The vibration-based load detector detects a vibration of the housing in an axial direction of the output shaft based on the detection signal and detects a load on the output shaft based on the detected vibration.
    Type: Application
    Filed: October 3, 2017
    Publication date: April 12, 2018
    Applicant: MAKITA CORPORATION
    Inventors: Ryo UMEMOTO, Hirokatsu YAMAMOTO, Kunihisa SHIMA
  • Publication number: 20180099392
    Abstract: An electric power tool includes a housing, a motor, an output shaft, an acceleration sensor, and a twisted-motion detector. The housing is configured to house the motor and the output shaft. The acceleration sensor is configured to detect acceleration of the housing. The twisted-motion detector is configured to repeatedly obtain acceleration of the housing in the circumferential direction of the output shaft, to calculate a speed by integrating, of the obtained accelerations, accelerations obtained in a certain period, and to detect twisting of the housing from the speed.
    Type: Application
    Filed: October 3, 2017
    Publication date: April 12, 2018
    Applicant: MAKITA CORPORATION
    Inventors: Hikaru SUNABE, Hirokatsu YAMAMOTO, Takaaki OSADA
  • Publication number: 20180099394
    Abstract: An electric power tool according to one aspect of the present disclosure includes a main body, a motor, a tool holder configured to hold a tool bit, a hammer, a motion converter, a rotation transmitter, a first load detector, a second load detector, and a motor controller. The first load detector detects, based on information indicating a drive state of the motor, a load imposed from a work piece to the tool bit. The second load detector detects, based on information indicating a behavior of the main body, a load imposed from the work piece to the tool bit. The motor controller sets an upper limit of rotational speed of the motor to a predetermined no-load rotational speed in response to no-load on the tool bit being detected by both the first load detector and the second load detector.
    Type: Application
    Filed: October 4, 2017
    Publication date: April 12, 2018
    Applicant: MAKITA CORPORATION
    Inventors: Yoshitaka ICHIKAWA, Hirokatsu YAMAMOTO, Ryo UMEMOTO, Kunihisa SHIMA
  • Publication number: 20180092297
    Abstract: A working machine according to one aspect of the present disclosure includes a main body portion, a driving device, a working tool, a grip portion and a determiner. The grip portion is attached to the main body portion and configured to be held by a user of the working machine. The determiner is configured to determine an abnormal state of the working machine when a couple moment received by the user through the grip portion exceeds a couple threshold. The couple threshold is 200 N·m per 50 ms.
    Type: Application
    Filed: October 4, 2017
    Publication date: April 5, 2018
    Applicant: MAKITA CORPORATION
    Inventors: Ryo SUNAZUKA, Yuji TAKAHASHI, Hirokatsu YAMAMOTO, Kouichi TAKEDA, Shinya KOJIMA
  • Publication number: 20180080453
    Abstract: A backpack-type blower according to one aspect of the present disclosure includes a plurality of fans, a plurality of DC power supplies and a backpack. The plurality of fans and the plurality of DC power supplies are mounted on the backpack. The backpack-type blower is configured to blow winds from the plurality of fans together.
    Type: Application
    Filed: April 19, 2016
    Publication date: March 22, 2018
    Applicant: MAKITA CORPORATION
    Inventors: Hirokatsu YAMAMOTO, Yuki KAWAI, Makoto TAKAHASHI
  • Publication number: 20180038546
    Abstract: An electric power tool in one aspect of the present disclosure comprises a main body, a motor, a driver, a detector, and a kickback determiner. The kickback determiner determines that the main body is kicked back from a workpiece when an attitude change amount of the main body detected by the detector exceeds a preset kickback determination threshold during driving of the motor by the driver.
    Type: Application
    Filed: July 26, 2017
    Publication date: February 8, 2018
    Applicant: MAKITA CORPORATION
    Inventors: Takeshi NISHIMIYA, Hirokatsu YAMAMOTO
  • Patent number: 9737984
    Abstract: It is an object of the invention to provide a technique for enhancing the operability of a power tool. A representative screwdriver 100 is provided which has a motor 110 and a driving mechanism 120. The driving mechanism 120 has a rotation transmitting mechanism including a driving cam 137 and a driven cam 157, and a cam engagement state is switched by movement of the spindle 150 in a longitudinal direction of the spindle. The position of the spindle 150 in the longitudinal direction is detected by a detecting mechanism 162 that is disposed on the opposite side of the rotation transmitting mechanism from a front end region in the longitudinal direction of the spindle 150. A controller 180 controls the rotation speed of the motor 110 based on the detection result of the detecting mechanism 162 and drives the motor 110.
    Type: Grant
    Filed: November 6, 2014
    Date of Patent: August 22, 2017
    Assignee: MAKITA CORPORATION
    Inventors: Hirokatsu Yamamoto, Takaaki Osada, Manabu Sugimoto
  • Publication number: 20170129090
    Abstract: An electric working machine including a motor, an electric-power supply unit, a control unit, and a signal processing unit. The signal processing unit performs a signal control process for sending and receiving a signal to and from the signal processing unit and an external device, and receives at least a stop-command signal from the external device. The control unit stops the electric power supply to the motor in a case where the stop-command signal is received at the signal processing unit when the electric power supply from the electric-power supply unit to the motor is in process.
    Type: Application
    Filed: November 2, 2016
    Publication date: May 11, 2017
    Applicant: MAKITA CORPORATION
    Inventor: Hirokatsu YAMAMOTO
  • Patent number: 9621081
    Abstract: A motor-driven apparatus in one aspect of the present disclosure includes: a brushless motor; a full-wave rectifier circuit; a drive circuit; a controller; and a forcible stop unit. The forcible stop unit performs a forcible stop control to temporarily forcibly stop a switching operation of a plurality of switching elements during a stop period when a full-wave rectified voltage is smaller than an induced voltage generated by a plurality of coils, and the switching operation of the plurality of switching elements is to be stopped.
    Type: Grant
    Filed: December 22, 2015
    Date of Patent: April 11, 2017
    Assignee: MAKITA CORPORATION
    Inventors: Yuki Kawai, Yoshitaka Ichikawa, Hirokatsu Yamamoto, Ying Yang
  • Publication number: 20170060471
    Abstract: A work apparatus in one aspect of the present disclosure comprises a control unit, a volatile memory and a rewritable non-volatile memory. The control unit comprises an update processing unit and a writing processing unit. The writing processing unit writes history information in the volatile memory into the non-volatile memory when the writing processing unit predicts a suspension of supply of an electric power to the control unit.
    Type: Application
    Filed: August 23, 2016
    Publication date: March 2, 2017
    Applicant: MAKITA CORPORATION
    Inventors: Hirokatsu YAMAMOTO, Yoshitaka ICHIKAWA
  • Publication number: 20160305438
    Abstract: A fluid aparatus includes an apparatus main body that includes a motor and a fan driven by the motor, a frame on which the apparatus main body is mounted, a pipe that is detachably attached to the apparatus main body to discharge and introduce a fluid by rotation of the fan, an operation unit that is provided to the pipe to input an operation command for the apparatus main body by operation from outside, a cable that transmits a signal between the operation unit and the apparatus main body, and a connecting portion that is provided to the cable to separably couple the operation unit and the apparatus main body to each other.
    Type: Application
    Filed: March 31, 2016
    Publication date: October 20, 2016
    Applicant: MAKITA CORPORATION
    Inventors: Hirokatsu YAMAMOTO, Yuki KAWAI, Makoto TAKAHASHI
  • Patent number: 9425730
    Abstract: The present application discloses an apparatus including: a motor model that reflects a characteristic of a motor and includes at least inputs pertaining to a first quantity of state and a second quantity of state and an output pertaining to a third quantity of state; a comparator that calculates a difference between the third quantity of state in an actual motor and the third quantity of state output from the motor model; and an amplifier that amplifies an output of the comparator at a predetermined gain. The first quantity of state in the actual motor is input into the motor model as the first quantity of state, and an output of the amplifier is input into the motor model as the second quantity of state. The apparatus then uses the output of the amplifier as an estimated value of the second quantity of state in the actual motor.
    Type: Grant
    Filed: January 19, 2012
    Date of Patent: August 23, 2016
    Assignee: MAKITA CORPORATION
    Inventors: Masahiko Sako, Hirokatsu Yamamoto, Takaaki Osada
  • Publication number: 20160190960
    Abstract: A motor-driven apparatus in one aspect of the present disclosure includes: a brushless motor; a full-wave rectifier circuit; a drive circuit; a controller; and a forcible stop unit. The forcible stop unit performs a forcible stop control to temporarily forcibly stop a switching operation of a plurality of switching elements during a stop period when a full-wave rectified voltage is smaller than an induced voltage generated by a plurality of coils, and the switching operation of the plurality of switching elements is to be stopped.
    Type: Application
    Filed: December 22, 2015
    Publication date: June 30, 2016
    Applicant: MAKITA CORPORATION
    Inventors: Yuki KAWAI, Yoshitaka ICHIKAWA, Hirokatsu YAMAMOTO, Ying YANG
  • Publication number: 20160151845
    Abstract: A reciprocating electric power tool in one aspect of the present invention includes an attachment unit, a motor, a power transmission unit, and a controller. The controller is configured to operate the motor at a first speed when activated; to operate the motor at a second speed that is higher than the first speed when a first condition is satisfied after activation; and, to operate the motor at a third speed that is higher than the second speed when a second condition is satisfied after the first condition is satisfied.
    Type: Application
    Filed: March 31, 2014
    Publication date: June 2, 2016
    Applicant: MAKITA CORPORATION
    Inventors: Hirokatsu YAMAMOTO, Takaaki OSADA, Yasushi OGURA
  • Publication number: 20150137721
    Abstract: A power tool comprises a motor, an output torque calculation unit configured to calculate an output torque of the motor based on a current flowing through the motor, a friction torque calculation unit configured to calculate a friction torque of the motor based on a rotation speed of the motor, a load torque estimation unit configured to estimate a load torque acting on the motor, an inertia torque calculation unit configured to calculate an inertia torque based on the output torque, the friction torque and the load torque, and a motor deceleration unit configured to stop or decelerate the motor when the inertia torque is greater than an inertia torque reference value.
    Type: Application
    Filed: October 20, 2014
    Publication date: May 21, 2015
    Inventors: Hirokatsu YAMAMOTO, Takaaki OSADA
  • Publication number: 20150122523
    Abstract: It is an object of the invention to provide a technique for enhancing the operability of a power tool. A representative screwdriver 100 is provided which has a motor 110 and a driving mechanism 120. The driving mechanism 120 has a rotation transmitting mechanism including a driving cam 137 and a driven cam 157, and a cam engagement state is switched by movement of the spindle 150 in a longitudinal direction of the spindle. The position of the spindle 150 in the longitudinal direction is detected by a detecting mechanism 162 that is disposed on the opposite side of the rotation transmitting mechanism from a front end region in the longitudinal direction of the spindle 150. A controller 180 controls the rotation speed of the motor 110 based on the detection result of the detecting mechanism 162 and drives the motor 110.
    Type: Application
    Filed: November 6, 2014
    Publication date: May 7, 2015
    Inventors: Hirokatsu YAMAMOTO, Takaaki OSADA, Manabu SUGIMOTO