Hitachi Koki Co., Ltd.

Hiroaki Orikasa

Yoshio Iimura

Mitsuhiro Sunaoshi

Kazuhiro Segawa

Shigeru Shinohara

Toshiaki Uchida

Takahiko Shimada

Kazuhiko Funabashi

Chikai Yoshimizu

Atsushi Nakagawa

Eiji Nakayama

Masateru Niyada

Kazumi Takeishi

Hiroyasu Ishikawa

Siyouiti Sakamoto

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.

For a motor that drives a compressed air generator, three operating modes which includes a powerful mode for rotating a motor in a high speed range, a silent mode for rotating the motor in a low speed range, and an automatic mode for automatically changing the rotation speed of the motor from the low speed to the high speed in accordance with a setup condition are prepared. A user can designate a desired operating mode by using an operating mode selection switch.

Air compressor having a controller for a variable speed motor and a compressed air tank

A control circuit portion in an air compressor finds the rate of decrease of pressure inside a tank portion when a motor is at rest relative to the time based on a detection signal from a pressure sensor. Where the rate of decrease of pressure is greater than a given value, the motor is started without waiting for the pressure inside the tank to decrease to a motor restart pressure value, the pressure inside the tank portion rises to a given motor stop pressure value and the motor is then controlled to come to a stop. Where the rate of decrease of pressure is less than the given value, the motor is started when the pressure inside the tank has decreased to the motor restart pressure value. After the start of the motor, the motor is controlled such that it comes to a stop when the pressure inside the tank portion increases to a given value lower than the motor stop pressure value.

Air compressor

An air compressor comprises a tank portion for reserving a compressed air, a compressed air generating portion for generating the compressed air to be supplied to the tank portion, a motor for driving the compressed air generating portion, and a pressure switch mechanism having a pressure sensor in a part of the tank portion, and controlling the motor to be turned on or off in accordance with an output of the pressure sensor, characterized in that when the time change rate of the pressure within air tank is greater than a predetermined value, the motor is restarted without waiting until the pressure decreases to the switch on point at the time of pressure fall.

Pressure switch mechanism and air compressor using the same mechanism

An air compressor includes a tank unit storing a compressed air used by a pneumatic tool, a compressed air generator which generates the compressed air and supplies the compressed air to the tank unit, a motor driving the compressed air generator, a drive portion including the motor, a controller portion controlling the drive portion and a pressure sensor detecting an air pressure of the compressed air in the tank unit, in which the controller portion controls a rotation speed of the motor at multiple levels based on a detection signal Pof the pressure sensor, a first differential signal which is a differential value d(P)/dt of the detection signal P, and a second differential signal which is a differential value d(P)/dt of a detection signal Pobtained by removing a pulsatory element from the detection signal P

Air compressor and control method therefor

A DC power source unit includes a main unit that generates DC voltage, and an output cable. The output cable is connected, either integrally or detachably, at one end to the output of the main unit and another end to an adapter plug. The adapter plug is electrically connected to an electrically powered tool, such as an electrical drill. An output voltage switching unit switches the level of voltage supplied by the main unit to the electrically powered tool, to a level that matches the rated voltage of the electrically powered tool that corresponds to the fitting portion of the adapter plug.

DC power source unit

A DC power source unit includes a main unit that generates DC voltage, and an output cable. The output cable has one end connected to the output of the main unit and another end attached to an adapter plug. The adapter plug Is electrically connected to an electrically powered tool, such as an electrical drill. Current flowing in the tool is detected every predetermined interval and accumulated electrical quantity is computed based on the detected current flowing in the tool. Based on the accumulated electrical quantity, the temperature of the tool is predicted. When it is determined that the tool is heated up to a first critical temperature based on the accumulated electrical quantity, an alarm unit is actuated. When it is determined that the tool is further heated up to a second critical temperature, supply of current to the tool is interrupted.

DC power source unit alarming before electrically powered tool is overheated and stopping power supply thereafter

A saber saw assembly includes a vice for clamping an object to be cut and a saber saw having a saw blade to be operated in reciprocating motion. The saber saw is arranged to cut the object with the reciprocating saw blade while the object is clamped by the vice. The vice is in the form of a pipe wrench. The pipe wrench clamps the object when rotated in a clamping direction while releases the object when rotated in a releasing direction opposite to the clamping direction. Accordingly, by using the pipe wrench for the vice, the clamping and releasing operations for the object are simplified to enhance the working efficiency for cutting the object.

Saber saw assembly with improved vising mechanism

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 power-driven bolt fastening tool or shearing wrench includes an outer socket adapted to fit over the head of a bolt to be fastened and an inner socket disposed coaxially in the outer socket and adapted to fit over the tip of the bolt. A planetary gear mechanism comprises an internal gear coupled to the outer socket through a lost-motion connection, planet gears supported on shafts coupled to the inner socket, and a sun gear in mesh with the planet gears. The lost-motion connection comprises a torsion spring acting between the internal gear and the outer socket for allowing the internal gear to angularly move for a limited angular interval before the outer and inner sockets fit fully over the bolt head and tip and before a fastening torque is transmitted from the sun gear to the outer socket.

Growing community of inventors

Ibaraki, Japan

Hiroaki Orikasa