Patents Assigned to Hitachi Koki Company, Limited
  • Publication number: 20030010510
    Abstract: Two guide members cooperatively constitute a chuck portion for holding a screw head. Opening and closing of the chuck portion is regulated depending on a mutual position between a machine body and a member into which a screw is driven. Guide pin portions of respective guide members engage with a stopper portion of a push lever until a screw is driven to a predetermined depth. The chuck potion tightly holds the screw head until a screw fastening operation is substantially finished, thereby suppressing the lifting of a machine body.
    Type: Application
    Filed: July 5, 2002
    Publication date: January 16, 2003
    Applicant: HITACHI KOKI COMPANY LIMITED
    Inventors: Takeshi Kamo, Yasuo Sasaki, Michio Wakabayashi
  • Patent number: 6330405
    Abstract: In an image forming apparatus, the developing unit includes two developing rollers whose rotational directions are different from each other, and a bias potential of the developing roller (first developing roller) located upstream in the rotational direction of the photosensitive member is selected to be a potential, which is in value between a bias potential of the developing roller (second developing roller) located downstream in the same direction and a background potential.
    Type: Grant
    Filed: December 11, 2000
    Date of Patent: December 11, 2001
    Assignee: Hitachi Koki Company Limited
    Inventors: Masayoshi Ishii, Hiroyuki Mabuchi, Koji Kato
  • Patent number: 6137968
    Abstract: There are disposed optical sensors (S1, S2, S3,S4, S5, and S6) outside sheet trays (1, 2, 3). The optical axes of the optical sensors are respectively set in such a manner that they are parallel to their associated up-down tables (1a, 2a, and 3a) and pass upwardly of contact positions (A, B and C) between sheets (P) and sheet supply rollers (20, 21, and 22).
    Type: Grant
    Filed: October 29, 1999
    Date of Patent: October 24, 2000
    Assignee: Hitachi Koki Company Limited
    Inventors: Kazuo Sunou, Junji Shirakawa, Takayuki Muneyasu
  • Patent number: 5673758
    Abstract: An improved structure of an impact screwdriver is provided which achieves a low-noise screw-driving operation. The impact screwdriver includes a clutch assembly for transmitting torque provided by a motor to a tool bit. The clutch assembly includes a toque-transmitting member, a torque-outputting member, and a clutch coil spring. The clutch coil spring is selectively wound around the torque-transmitting member and the torque-outputting member according to a rotational difference therebetween to establish torque transmission for providing the torque to the tool bit intermittently.
    Type: Grant
    Filed: June 1, 1995
    Date of Patent: October 7, 1997
    Assignee: Hitachi Koki Company Limited
    Inventors: Yasuo Sasaki, Mitsuo Ogura
  • Patent number: 5619422
    Abstract: A rotor temperature control system for a centrifuge is provided. This system includes an ambient temperature sensor for detecting ambient temperature around the system, a temperature regulating device for regulating temperature of a rotor of the centrifuge according to an operation factor which is variable within a range of preselected maximum to minimum values, and an operation factor controller for controlling a value the operation factor of the temperature regulating device in a preselected relation to the ambient temperature and a given target rotor temperature to modify the temperature of the rotor to the target rotor temperature. With this arrangement, the temperature of the rotor is modified to a desired value quickly regardless of an initial temperature of the rotor.
    Type: Grant
    Filed: December 17, 1993
    Date of Patent: April 8, 1997
    Assignee: Hitachi Koki Company Limited
    Inventors: Takashi Nakazawa, Shinji Azuma, Norihisa Sagawa
  • Patent number: 5610465
    Abstract: A high-frequency motor comprises a squirrel-cage rotor. The rotor comprises an iron core having a plurality of circular slots, a plurality of conductive rods inserted into the slots, and short-circuit rings disposed at both ends of the conductive rods. The conductive rods are made of copper. A ratio of a product of the number N2 of the conductive rods and a diameter d2 of each conductive rod to an outer diameter D of the rotor is in an optimized range of 1.1 to 1.5, namely, 1.1.ltoreq.N2.multidot.d2/D.ltoreq.1.5. With this optimization, it becomes possible to achieve a maximum rotational speed of more than 120,000 min.sup.-1 and obtain an excellent motor efficiency.
    Type: Grant
    Filed: May 17, 1995
    Date of Patent: March 11, 1997
    Assignee: Hitachi Koki Company Limited
    Inventors: Shinichi Sakamoto, Masanori Kobayashi
  • Patent number: 5601149
    Abstract: A percussion hammer tool comprises a spindle 1 causing rotation about an axis thereof. The spindle 1 is driven by a motor M. A hammer 3, slidably coupled with the spindle 1, generates a percussion force to rotate and hit an anvil. The anvil is divided into an engaging portion 7 engageable with the hammer 3 and a tip tool holding portion 8 holding a tip tool 16. The engaging portion 7 and the tip tool holding portion 8 are locked with each other. A torque transmitting mechanism 11 makes the engaging portion 7 and the tip tool holding portion 8 displaceable with each other telescopically in an axial direction. A cushion member 10 is provided in a clearance 9a between the engaging portion 7 and the tip tool holding portion 8, thereby transmitting an angular component of the percussion force while absorbing an axial component of the percussion force. An additional cushion member 13 may be interposed between the spindle 1 and the anvil.
    Type: Grant
    Filed: January 25, 1995
    Date of Patent: February 11, 1997
    Assignee: Hitachi Koki Company Limited
    Inventors: Yoshimitsu Kawasaki, Mitsuyuki Ishikawa, Takao Tanabe, Toshiaki Uchida
  • Patent number: 5558571
    Abstract: A grinder has a grinding member. The grinder includes a rotatable spindle having an engagement portion. A first flange engages the engagement portion of the spindle. The first flange and the engagement portion of the spindle define a given play therebetween in a direction of rotation. The grinding member is held between the first flange and a second flange. A lubricant solid material is provided between the first flange and the engagement portion of the spindle.
    Type: Grant
    Filed: June 17, 1994
    Date of Patent: September 24, 1996
    Assignee: Hitachi Koki Company Limited
    Inventors: Takeshi Toyoshima, Yo Kawakami, Hiroyasu Ishikawa, Takao Abe, Satsuo Sato, Nobuhiro Noto, Tadahiro Kaneko, Takayoshi Kaneta, Juurou Kobayahsi, Osamu Kawanobe
  • Patent number: 5522466
    Abstract: A vibration-damping apparatus for an electric hammer unit is provided. This vibration-damping apparatus is provided with the so-called transatory unit including elastic bars disposed between elastic damper members connected to a tool body and a handle of the electric hammer unit, respectively, for absorbing relative displacement of the elastic damper members caused by vibrations produced by the tool body during use. The vibration-damping apparatus further includes a stopper member attached to the elastic damper member attached to the handle so as to engage a chamber formed in the elastic damper member attached to the tool body for preventing the handle from being dislodged from the tool body even when the handle is swung laterally by a hammer operator.
    Type: Grant
    Filed: March 17, 1995
    Date of Patent: June 4, 1996
    Assignee: Hitachi Koki Company Limited
    Inventors: Mutsuo Harada, Akihisa Yahagi
  • Patent number: 5456324
    Abstract: A percussion hammer for a tool includes a rotational drive source. A motion converting mechanism is connected to the rotational drive source for convening rotational movement of the rotational drive source into reciprocating movement. A striking mechanism is connected to the motion converting mechanism, and has a drive cylinder. A rotation transmitting mechanism is operative for transmitting rotational movement from the rotational drive source to the tool. A drive wheel is connected to the rotational drive source, and extends around the drive cylinder. A coupling member is connected to the drive cylinder, and extends around the drive cylinder. The coupling member is movable in a percussion axis direction. A movable adjustment member is connected to the coupling member for selectively connecting and disconnecting the coupling member to and from the drive wheel. Teeth are formed on an outer circumferential surface of the drive cylinder.
    Type: Grant
    Filed: July 19, 1994
    Date of Patent: October 10, 1995
    Assignee: Hitachi Koki Company Limited
    Inventors: Toshiaki Takagi, Yoshihiko Watanabe
  • Patent number: 5346023
    Abstract: A slipping torque changing mechanism for an impact tool includes a driving source for generating a rotational motion. A motion converting mechanism is connected with this driving source for converting the rotational motion of the driving source into a reciprocating motion. An impact mechanism is connected with this motion converting mechanism for transmitting the reciprocating motion to a tool end. A rotational motion transmitting mechanism is disposed separately from the motion converting mechanism for transmitting the rotational motion of the driving source to the tool end. A plurality of clutches, having different slipping torques, are disposed at different portions on the rotational motion transmitting mechanism.
    Type: Grant
    Filed: February 11, 1993
    Date of Patent: September 13, 1994
    Assignee: Hitachi Koki Company Limited
    Inventors: Toshiaki Takagi, Yoshihiko Watanabe
  • Patent number: 5342280
    Abstract: A management system for use in a centrifuge equipped with a detachable rotor which is rotatable so as to separate density-different samples by a centrifugal force due to the rotation. The management system is for managing the lifetime of the rotor on the basis of the detection results of an operated-condition detector for detecting operated conditions such as the number of times of rotation, running time and rotational speed of the rotor. The management system includes a data storing device which is provided on the rotor to be rotatable therewith and is composed of a magnetic recording medium to allow keeping data relating to the operated conditions of the rotor. Also included in the management system is a data processing unit coupled through a data reading and writing device such as a magnetic head to the data keeping device and also coupled to the operated-condition detector to be responsive to the operated conditions.
    Type: Grant
    Filed: August 17, 1993
    Date of Patent: August 30, 1994
    Assignee: Hitachi Koki Company Limited
    Inventors: Yoshitaka Niinai, Akio Nagata, Norihisa Sagawa, Shigeru Shinohara, Eiji Nakayama, Mitsutoshi Yotsuyanagi, Hiroshi Hayasaka, Kazuyoshi Tokunaga
  • Patent number: 5325172
    Abstract: An optical system is provided with a laser device for emitting a multiplet laser beam with two types of frequencies F1, F2, and a sample rotator on which a reference sample and a test sample containing substances are set for rotating both the test sample and the reference sample to separate the substances contained in the test sample. The test sample and the reference sample are irradiated with the multiplet laser beam one after another to shift the phase of the laser beam. The optical system is further provided with a polarizer for polarizing the multiplet laser beams transmitting through the test sample and the reference sample to produce both a test sample signal with a frequency .DELTA.F=F1-F2 and a reference sample signal with the frequency .DELTA.F, and a signal analyzer for analyzing a phase difference between the sample signals to determine an index of refraction of the test sample. Therefore, the substances containing in the test sample are specified.
    Type: Grant
    Filed: January 13, 1993
    Date of Patent: June 28, 1994
    Assignee: Hitachi Koki Company Limited
    Inventors: Keiji Kataoka, Sadamoto Tachihara, Masakuni Koreeda
  • Patent number: D580247
    Type: Grant
    Filed: March 25, 2008
    Date of Patent: November 11, 2008
    Assignee: Hitachi Koki Company Limited
    Inventors: Takeshi Taniguchi, Hitoshi Tsuzuki, Akira Onose
  • Patent number: D337711
    Type: Grant
    Filed: July 10, 1991
    Date of Patent: July 27, 1993
    Assignee: Hitachi Koki Company Limited
    Inventors: Yasunori Ogawa, Kazuhiko Kitaguchi
  • Patent number: D343345
    Type: Grant
    Filed: March 25, 1992
    Date of Patent: January 18, 1994
    Assignee: Hitachi Koki Company Limited
    Inventors: Yasunori Ogawa, Norio Nitta, Kazuhiro Segawa
  • Patent number: D345682
    Type: Grant
    Filed: January 7, 1993
    Date of Patent: April 5, 1994
    Assignee: Hitachi Koki Company Limited
    Inventors: Yuichiro Sasaki, Toshiaki Uchida
  • Patent number: D349029
    Type: Grant
    Filed: May 18, 1993
    Date of Patent: July 26, 1994
    Assignee: Hitachi Koki Company Limited
    Inventors: Naoki Matsunaga, Hideaki Hasegawa, Yoshihiko Watanabe, Toshiaki Takagi
  • Patent number: D367867
    Type: Grant
    Filed: May 3, 1995
    Date of Patent: March 12, 1996
    Assignee: Hitachi Koki Company Limited
    Inventors: Junichi Suzuki, Yoshitaka Niinai
  • Patent number: D380132
    Type: Grant
    Filed: May 18, 1995
    Date of Patent: June 24, 1997
    Assignee: Hitachi Koki Company Limited
    Inventors: Naoki Matsunaga, Hideaki Hasegawa, Yoshihiko Watanabe, Toshiaki Takagi, Seiichi Kodato