Hitachi Koki Co., Ltd.

Toshiaki Uchida

Yuichiro Sasaki

Hiroaki Orikasa

Yoshio Iimura

Mitsuhiro Sunaoshi

Kazuhiro Segawa

Kazuhiko Funabashi

Eiji Nakayama

Shigeru Shinohara

Masateru Niyada

Mitsuyuki Ishikawa

Hiroyasu Ishikawa

Yoshimitsu Kawasaki

Takao Tanabe

Toshihide Sasaki

To provide a power tool which can supply electric power again from a battery even in a case where the supply of electric power from the battery is stopped by an over-discharge detection means. A power toolincludes an FET driving circuitwhich permits the supply of electric power again to a motorfrom a battery packin response to the turning-on of a trigger switcheven in the case where the battery packis placed in an over-discharge state and so the supply of electric power to the motorfrom the battery packis stopped.

Power tool

An air compressor includes: a tank portion for reserving compressed air used in a pneumatic tool; a compressed air generation portion for generating compressed air and supplying the compressed air to the tank portion; a drive portion including a motor for driving the compressed air generation portion; a control circuit portion for controlling the drive portion; and a pressure sensor for detecting pressure of the compressed air reserved in the tank portion. The control circuit portion includes a unit for controlling the rotational speed of the motor multistageously based on a detection signal output from the pressure sensor.

Air compressor and method for controlling the same

An air compressor includes: a tank portion for reserving compressed air used in a pneumatic tool; a compressed air generation portion for generating compressed air and supplying the compressed air to the tank portion; a drive portion including a motor for driving the compressed air generation portion; a control circuit portion for controlling the drive portion; and a pressure sensor for detecting pressure of the compressed air reserved in the tank portion. The control circuit portion includes a unit for controlling the rotational speed of the motor multistageously on the basis of a detection signal output from the pressure sensor.

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.

Noise reduction mechanism for percussion tools

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.

Growing community of inventors

Ibaraki, Japan

Toshiaki Uchida