Patents by Inventor Shinji Kuragano
Shinji Kuragano 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).
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Publication number: 20220241877Abstract: Provided is a power tool capable of suitably fixing an auxiliary member to a base pedestal. The power tool has a base 30 having a sliding surface capable of sliding on a workpiece, and an auxiliary member 60 that is attachable to the base 30 and has a guiding surface 61. The power tool also has a wing bolt 33 and a leaf spring 35 as a pressing mechanism capable of pressing an extension part 62 of the auxiliary member 60. An operator can change a pressing force of the wing bolt 33 to the auxiliary member 60 by changing the position of the wing bolt 33 in a pressing direction. The leaf spring 35 applies a predetermined pressing force to the auxiliary member 60 even in the absence of the pressing force of the wing bolt 33 to the auxiliary member 60.Type: ApplicationFiled: June 26, 2020Publication date: August 4, 2022Applicant: Koki Holdings Co., Ltd.Inventors: Yoshiaki Osada, Shinji Kuragano, Takeru Kumakura
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Patent number: 11211894Abstract: Provided is an electric tool capable of continuing work by making the electrical advance angle of a brushless motor changeable even when a load is heavy. The electric tool is provided with: a brushless motor; a controller for controlling the drive of the brushless motor; and an inverter circuit supplied with a pulsation voltage obtained by rectifying an AC power supply input in a full-wave manner and electrifying the brushless motor 1 according to a control signal of the controller. The controller can change the electrical advance angle of the brushless motor. The controller detects the motor current flowing through the brushless motor and increases the electrical advance angle when the motor current reaches a predetermined threshold value.Type: GrantFiled: March 30, 2018Date of Patent: December 28, 2021Assignee: Koki Holdings Co., Ltd.Inventors: Takeru Kumakura, Hideyuki Tanimoto, Takuya Yoshinari, Shinji Kuragano
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Patent number: 11007586Abstract: Provided is a portable cutter wherein the entire base has increased strength. This portable cutter is provided with: a body having a prime mover and a saw blade which is driven by the prime mover; a base having a through-hole through which the saw blade protrudes and sliding on a material to be cut; and a stand which rises from the base and to which the body is connected. If the direction in which cutting progresses is designated as a front-rear direction, a rib extending in the front-rear direction is provided to the base. The stand is configured such that, in the left-right direction, the stand is either located outside a region in which the through-hole is formed, or extended to the outside of the region. The positions, in the front-rear direction, of the stand and the rib partially overlap each other.Type: GrantFiled: November 22, 2017Date of Patent: May 18, 2021Assignee: Koki Holdings Co., Ltd.Inventor: Shinji Kuragano
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Publication number: 20210119566Abstract: Provided is an electric tool capable of continuing work by making the electrical advance angle of a brushless motor changeable even when a load is heavy. The electric tool is provided with: a brushless motor; a controller for controlling the drive of the brushless motor; and an inverter circuit supplied with a pulsation voltage obtained by rectifying an AC power supply input in a full-wave manner and electrifying the brushless motor 1 according to a control signal of the controller. The controller can change the electrical advance angle of the brushless motor. The controller detects the motor current flowing through the brushless motor and increases the electrical advance angle when the motor current reaches a predetermined threshold value.Type: ApplicationFiled: March 30, 2018Publication date: April 22, 2021Applicant: Koki Holdings Co., Ltd.Inventors: Takeru KUMAKURA, Hideyuki TANIMOTO, Takuya YOSHINARI, Shinji KURAGANO
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Patent number: 10702932Abstract: To provide a power tool configured to stably rotate an end tool. The provided power tool includes a brushless motor including a rotor configured to rotate; a rectifier circuit configured to rectify an AC voltage; a smoothing capacitor configured to smooth the AC voltage rectified by the rectifier circuit to a pulsating voltage; an inverter circuit configured to perform switching operations to output the pulsating voltage to the brushless motor; a deceleration mechanism including: a driving portion at a rotor side, a driven portion configured to transmit a rotating force to an end tool side, and an elastic member configured to transmit a rotational force of the driving portion to the driven portion, the deceleration mechanism configured to decelerate a speed of a rotation of the rotor and configured to transmit the rotation to an end tool.Type: GrantFiled: February 26, 2016Date of Patent: July 7, 2020Assignee: Koki Holdings Co., Ltd.Inventors: Takeru Kumakura, Shinji Kuragano
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Patent number: 10658957Abstract: A power tool includes a brushless motor, a supplying circuit, and a controller. The brushless motor is configured to drive and rotate when a voltage applied to the brushless motor is larger than or equal to an induced voltage. The supplying circuit is configured to apply a driving voltage to the brushless motor. The controller is configured to control the supplying circuit. The supplying circuit includes a rectifying circuit, a capacitor, and a switching circuit. The rectifying circuit is configured to rectify an alternating voltage and output a rectified voltage. The capacitor is configured to smooth the voltage inputted via the rectifying circuit. The switching circuit is configured to perform a switching operation based on a PWM signal to adjust a period during which the driving voltage is applied. The controller is configured to set a duty ratio within a prescribed range, and output the PWM signal of the set duty ratio to the switching circuit to control the switching operation.Type: GrantFiled: March 31, 2017Date of Patent: May 19, 2020Assignee: Koki Holdings Co., Ltd.Inventors: Shinji Kuragano, Takeru Kumakura
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Publication number: 20190388984Abstract: Provided is a portable cutter wherein the entire base has increased strength. This portable cutter is provided with: a body having a prime mover and a saw blade which is driven by the prime mover; a base having a through-hole through which the saw blade protrudes and sliding on a material to be cut; and a stand which rises from the base and to which the body is connected. If the direction in which cutting progresses is designated as a front-rear direction, a rib extending in the front-rear direction is provided to the base. The stand is configured such that, in the left-right direction, the stand is either located outside a region in which the through-hole is formed, or extended to the outside of the region. The positions, in the front-rear direction, of the stand and the rib partially overlap each other.Type: ApplicationFiled: November 22, 2017Publication date: December 26, 2019Applicant: Koki Holdings Co., Ltd.Inventor: Shinji KURAGANO
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Patent number: 10391599Abstract: There is provided an electric power tool having a plurality of operation modes with different rotation speeds at least in a predetermined load range. The electric power tool is capable of switching between the operation modes when a predetermined condition is satisfied even during a motor is driven, and configured such that a rotation speed of the motor is changed smoothly or in a stepwise manner at the switching between the operation modes.Type: GrantFiled: July 10, 2014Date of Patent: August 27, 2019Assignee: KOKI HOLDINGS CO., LTD.Inventors: Kenichirou Yoshida, Akira Onose, Shinji Kuragano, Takuya Konnai
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Publication number: 20190131899Abstract: A power tool includes a brushless motor, a supplying circuit, and a controller. The brushless motor is configured to drive and rotate when a voltage applied to the brushless motor is larger than or equal to an induced voltage. The supplying circuit is configured to apply a driving voltage to the brushless motor. The controller is configured to control the supplying circuit. The supplying circuit includes a rectifying circuit, a capacitor, and a switching circuit. The rectifying circuit is configured to rectify an alternating voltage and output a rectified voltage. The capacitor is configured to smooth the voltage inputted via the rectifying circuit. The switching circuit is configured to perform a switching operation based on a PWM signal to adjust a period during which the driving voltage is applied. The controller is configured to set a duty ratio within a prescribed range, and output the PWM signal of the set duty ratio to the switching circuit to control the switching operation.Type: ApplicationFiled: March 31, 2017Publication date: May 2, 2019Applicant: Koki Holdings Co., Ltd.Inventors: Shinji Kuragano, Takeru Kumakura
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Patent number: 10201865Abstract: A portable electric cutter includes a housing in which a motor is accommodated, a saw blade driven to rotate by the motor, a base coupled to the housing and having a bottom surface slidable on a surface of a material to be cut, a fan driven to rotate by the motor, a driving circuit for switching power supplied to the motor, and a control circuit for controlling the driving circuit. A circuit board on which the driving circuit, the control circuit and others are mounted is provided, motor cooling air vents are provided in the housing on a side opposite to the saw blade, and circuit board cooling air vents are provided in the housing on the side opposite to the saw blade.Type: GrantFiled: October 2, 2017Date of Patent: February 12, 2019Assignee: Koki Holdings Co., Ltd.Inventors: Hayato Yamaguchi, Hideyuki Tanimoto, Kenichirou Yoshida, Shinji Kuragano
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Patent number: 10099303Abstract: An electric power tool includes a brushless motor, a control unit configured to control power supply to the brushless motor, a rotary tool configured to be rotated by the brushless motor, a rotation speed detecting unit configured to detect a rotation speed of the brushless motor, a main switch configured to transmit, to the control unit, an ON/OFF signal for switching between driving and stopping of the brushless motor, and a mode switching unit configured to transmit, to the control unit, a mode switching signal for switching between multiple modes of rotation control of the brushless motor, the control unit is configured to perform the rotation control of the brushless motor in any one of the multiple modes including at least a high-speed mode and a low-speed mode.Type: GrantFiled: August 4, 2014Date of Patent: October 16, 2018Assignee: HITACHI KOKI CO., LTD.Inventors: Kenichirou Yoshida, Akira Onose, Shinji Kuragano
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Patent number: 10027196Abstract: An electric tool includes a brushless motor having a plurality of phases, the brushless motor. The brushless motor includes a plurality of stator coils connected in parallel with each of the plurality of phases, and a plurality of crossover wires, each of the crossover wires being configured to electrically connect the plurality of stator coils for each of the plurality of phases to each other. The plurality of crossover wires for the plurality of phases are electrically connected to each other.Type: GrantFiled: February 14, 2015Date of Patent: July 17, 2018Assignee: HITACHI KOKI CO., LTD.Inventors: Kenichirou Yoshida, Shinji Kuragano
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Publication number: 20180050398Abstract: To provide a power tool configured to stably rotate an end tool. The provided power tool includes a brushless motor including a rotor configured to rotate; a rectifier circuit configured to rectify an AC voltage; a smoothing capacitor configured to smooth the AC voltage rectified by the rectifier circuit to a pulsating voltage; an inverter circuit configured to perform switching operations to output the pulsating voltage to the brushless motor; a deceleration mechanism including: a driving portion at a rotor side, a driven portion configured to transmit a rotating force to an end tool side, and an elastic member configured to transmit a rotational force of the driving portion to the driven portion, the deceleration mechanism configured to decelerate a speed of a rotation of the rotor and configured to transmit the rotation to an end tool.Type: ApplicationFiled: February 26, 2016Publication date: February 22, 2018Inventors: Takeru Kumakura, Shinji Kuragano
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Publication number: 20180021865Abstract: A portable electric cutter includes a housing in which a motor is accommodated, a saw blade driven to rotate by the motor, a base coupled to the housing and having a bottom surface slidable on a surface of a material to be cut, a fan driven to rotate by the motor, a driving circuit for switching power supplied to the motor, and a control circuit for controlling the driving circuit. A circuit board on which the driving circuit, the control circuit and others are mounted is provided, motor cooling air vents are provided in the housing on a side opposite to the saw blade, and circuit board cooling air vents are provided in the housing on the side opposite to the saw blade.Type: ApplicationFiled: October 2, 2017Publication date: January 25, 2018Inventors: Hayato YAMAGUCHI, Hideyuki TANIMOTO, Kenichirou YOSHIDA, Shinji KURAGANO
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Patent number: 9808872Abstract: A portable electric cutter includes a housing 2 in which a motor 1 is accommodated, a saw blade driven to rotate by the motor, a base 6 coupled to the housing 2 and having a bottom surface slidable on a surface of a material to be cut, a fan 7 driven to rotate by the motor, a driving circuit for switching power supplied to the motor, and a control circuit for controlling the driving circuit. A circuit board 60 on which the driving circuit, the control circuit and others are mounted is provided, motor cooling air vents are provided in the housing 2 on a side opposite to the saw blade, and circuit board cooling air vents are provided in the housing 2 on the side opposite to the saw blade.Type: GrantFiled: March 13, 2013Date of Patent: November 7, 2017Assignee: HITACHI KOKI CO., LTD.Inventors: Hayato Yamaguchi, Hideyuki Tanimoto, Kenichirou Yoshida, Shinji Kuragano
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Publication number: 20160193673Abstract: An electric power tool includes a brushless motor, a control unit configured to control power supply to the brushless motor, a rotary tool configured to be rotated by the brushless motor, a rotation speed detecting unit configured to detect a rotation speed of the brushless motor, a main switch configured to transmit, to the control unit, an ON/OFF signal for switching between driving and stopping of the brushless motor, and a mode switching unit configured to transmit, to the control unit, a mode switching signal for switching between multiple modes of rotation control of the brushless motor, the control unit is configured to perform the rotation control of the brushless motor in any one of the multiple modes including at least a high-speed mode and a low-speed mode.Type: ApplicationFiled: August 4, 2014Publication date: July 7, 2016Inventors: Kenichirou Yoshida, Akira Onose, Shinji Kuragano
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Publication number: 20160121509Abstract: A cordless circular saw includes a handle portion, a rechargeable battery which is removably attached to a battery attaching portion provided at the handle portion, a brushless motor which operates by electric power from the rechargeable battery, a control circuit board which has a controller for the brushless motor, a circular saw blade which is rotated by the brushless motor, and a gear cover which accommodates a mechanism for transmitting rotation between the brushless motor and the circular saw blade. The brushless motor is provided on one side of a left side and a right side of the handle portion. The gear cover and the circular saw blade are provided on the other side of the handle portion. The rechargeable battery extends from the handle portion toward the one side of the handle portion. The control circuit board is provided between the rechargeable battery and the circular saw blade.Type: ApplicationFiled: May 21, 2014Publication date: May 5, 2016Applicant: HITACHI KOKI CO., LTD.Inventor: Shinji Kuragano
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Patent number: 9197153Abstract: A power tool includes a housing, an electric motor accommodated in the housing, a secondary battery that supplies electric power to the electric motor, a handle provided at the housing, a trigger switch provided at the handle for controlling electric power supply to the electric motor, a residual capacity display for displaying a residual capacity of the secondary battery, and a lock-release switch provided at the handle and configured to allow the trigger switch to be operable and to start displaying the residual capacity at the residual capacity display upon manipulation to the lock-release switch.Type: GrantFiled: July 22, 2013Date of Patent: November 24, 2015Assignee: Hitachi Koki Co., Ltd.Inventors: Kenichirou Yoshida, Hideyuki Tanimoto, Hayato Yamaguchi, Shinji Kuragano, Takuya Konnai
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Publication number: 20150244226Abstract: An electric tool includes a brushless motor having a plurality of phases, the brushless motor. The brushless motor includes a plurality of stator coils connected in parallel with each of the plurality of phases, and a plurality of crossover wires, each of the crossover wires being configured to electrically connect the plurality of stator coils for each of the plurality of phases to each other. The plurality of crossover wires for the plurality of phases are electrically connected to each other.Type: ApplicationFiled: February 14, 2015Publication date: August 27, 2015Inventors: Kenichirou YOSHIDA, Shinji KURAGANO
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Patent number: D849495Type: GrantFiled: December 29, 2017Date of Patent: May 28, 2019Assignee: Hitachi Koki Co., Ltd.Inventors: Takeshi Taniguchi, Rui Akiba, Shinji Kuragano