Hitachi Koki Co., Ltd.

Hiroyasu Ishikawa

Masanori Ito

Yasuki Ohmori

Shigeru Shinohara

Yasuo Sasaki

Akira Uno

Nobuhiro Noto

Michio Wakabayashi

Hiroaki Orikasa

Mitsuo Ogura

Toshiaki Uchida

Masateru Niyada

Tadahiro Kaneko

Osamu Kawanobe

Satsuo Sato

Yo Kawakami

Takao Abe

Seiji Akiba

Takeshi Toyoshima

Juurou Kobayahsi

Takayoshi Kaneta

Jyuro Kobayashi

An air motor has a rotor rotatable in response to the pressure of pressurized air. A cylindrical rotary member is connected to the air motor for causing a rotation in synchronism with the rotation of the rotor. A rotary slider is slidable in the axial direction along the inner cylindrical wall of the rotary member. A rotational force transmitting mechanism is provided for transmitting the rotation of the rotary member to the rotary slider. A shaft has one end fixed to the rotary slider and the other end equipped with a piston and a driver bit holder. The rotational and axial motion of the rotary slider is transmitted to a driver bit held in the driver bit holder. And, a cylinder guides the axial slide movement of the piston responsive to the pressure of pressurized air applied on a pressure-receiving surface of the piston.

Pneumatically operated screw driver

An automatic drilling machine has an electric drilling unit on which a cylindrical cutter is rotatably mounted. The drilling machine includes a drill motor for rotating the cutter and a feed motor for linearly moving the cutter for the purpose of drilling into materials such as concrete. The current flowing through the drill motor before a drilling load is imposed thereon is detected for a microprocessor to determine the type of the cutter being used. The drill motor is driven at a rotation speed suitable for the cutter being used and the feed motor is driven at a speed such that the rotation speed of the drill motor thus set is maintained unchanged. Particularly, the drill motor is driven at a reduced rotation speed from the start of drilling until a predetermined drilling depth is reached to reduce chatter vibration which may otherwise be generated if the drill motor is driven at a regular constant speed from the beginning of drilling until the end.

Dual-motor-driven drilling machine and method of controlling currents

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.

Portable grinder

A portable power tool such as a portable circular saw is provided with a sawdust collection system based on the generation of an air flow resulting from rotation of a rotary cutting blade, with this air flow being guided to transport sawdust resulting from cutting operations along a guide path through a first discharge aperture into a dust box in which the sawdust is precipitated, with a low-velocity air flow then passing out of the dust box through a second discharge aperture to be recirculated through the flow path. Extremely effective dust collection is attained with a simple configuration, while the dust box can be positioned such that the weight of accumulated sawdust therein does not significantly affect the balance or ease of operation of the portable power tool.

Portable power tool equipped with dust collector

A power tool comprising a brush holder assembly formed of a plastic material, a printed circuit board and a positioning member for positioning the terminals of a switch and a power cable in contact with the printed circuit board. The brush holder assembly includes a pair of spaced apart arm portions each carrying a brush for making contact with the commutator and a web portion. In each of the arm portions of the assembly is embedded a pair of conductors each having a terminal at one end thereof for making electrical contact with a corresponding terminal of the stator, the other end of each conductor making contact with the printed circuit board. The printed circuit board is provided with a conductive pattern which permits the terminals of the switch and power cable to be mutually connected and further permits them to be connected to the conductors of the brush holder assembly to complete a series circuit.

Power tool having a printed circuit board

Growing community of inventors

Katsuta, Japan

Hiroyasu Ishikawa