Hitachi Koki Co., Ltd.

Takeshi Takeda

Tomomasa Nishikawa

Nobuhiro Takano

Eiji Nakayama

Kazuhiko Funabashi

Takao Aradachi

Kenrou Ishimaru

Hidekazu Harada

Masanori Okada

Takeshi Taniguchi

Katsuhiro Oomori

Yoshiki Aoki

Atsushi Nakagawa

Hiroki Uchida

Katsumi Kurihara

Mizuho Nakamura

Masayuki Ogura

Yuji Kishima

Tomoyuki Kawahara

Hironori Mashiko

Yutaka Ito

Takahiro Hirai

Takamoto Horiuchi

Atsushi Sumi

Hiroshi Ohira

Kazuhiro Funabashi

An electric tool including: a motor; a housing including, a motor housing accommodating the motor, and a handle housing having one end connected to the motor housing and another other end configured to be provided with a detachable battery pack; an output part partially accommodated in the motor housing and configured to be driven by the motor; and a control board accommodated in the motor housing and configured to control the motor.

Electric tool

There is provided a four-cycle engine which can appropriately circulate oil in an engine regardless of a tilted condition with a simple structure. A crankcase () of a four-cycle engine () has a crank room () which rotatably supports a crankshaft () and an oil room () which is provided adjacent to the exterior of the crank room (). The crankcase () also has partition walls () and () which partition the interior of the crankcase () into the crank room () and the oil room (), respectively, and a communication path () which communicates the crank room () with the oil room (). The partition walls () and () each has a cross section formed in a substantially V shape, and the communication path () is formed at an apex between the partition walls () and ().

Four-cycle engine, bush cutter and engine-driven tool having same

Portable electric driver

A DC power source unit supplies a DC voltage to a power tool through an adapter when a power switch of the tool is turned ON and also charges a battery pack used as an alternative power source of the tool when the power tool is not operated. In order to prevent a rush current from flowing in a switch interposed between a switching power source circuit and the battery pack when charging the battery pack is commenced, the switch is rendered OFF when the output voltage from the switching power source is greater than the battery voltage. Charging the battery is started upon once lowering the output of the switching power source to a level lower than the battery voltage.

DC power source unit with battery charging function

A DC power source unit supplies a DC voltage to a power tool through an adapter when a power switch of the tool is turned ON and also charges a battery pack used as an alternative power source of the tool when the power tool is not operated. A minimum battery temperature gradient amongst battery temperature gradients ever computed is used to determine whether the battery pack has cooling effect when forcibly cooled by a cooling fan or whether the battery pack has reached a full charge condition. When charging the battery pack is interrupted due to operation of the power tool, computing the battery temperature gradient is halted for some time or determination of the battery pack's full charge condition is not performed for some time in order to prevent the minimum battery temperature from being updated during interruption of charging of the battery pack.

A battery charger for charging a battery pack having a battery, a temperature sensor for sensing a temperature of the battery, and a battery terminal. The battery charger includes a charger terminal to which the battery terminal is connected when the battery is charged, a charge current generating circuit that generates a charge current for charging the battery, a battery temperature detector, and a controller. The battery temperature detector is configured to include a circuit, for example, to detect a temperature of the battery while cooperating with the temperature sensor and to output a temperature signal indicative of the temperature of the battery. The controller which is supplied with the temperature signal from the battery temperature detector, corrects the temperature signal, and provides a corrected temperature signal.

Battery charger capable of accurately detecting battery temperature for full charge determination

A DC power source unit supplies a DC voltage to an electrically powered tool through an adapter and also charges a battery pack used as an alternative power source of the tool. With the DC power source unit of the invention, a microcomputer receives a temperature signal indicative of a temperature of the battery pack and determines that the battery pack is fully charged based on the temperature signal. This determination is made regardless of whether the battery pack is being charged or not. As such, the fully charged condition of the battery pack can be accurately detected even if the tool is operated when the battery pack is almost fully charged.

A DC power source unit supplies a DC voltage to an electrically powered tool through an adapter and also charges a battery pack used as an alternative power source of the tool. With the DC power source unit of the invention, charging of the battery pack is stopped and supply of power to the tool is started instantaneously when the power switch of the tool is turned ON. The DC power source unit is also capable of outputting selective one of different drive voltages corresponding to the rated drive voltages of a variety of different tools and capable of charging battery packs with different battery voltages.

An adapter includes a cord, a fitting portion, a voltage setting unit, and a fitting prevention mechanism. The cord is adapted to connect to a DC power source unit in order to receive DC voltage from the DC power source unit. The fitting portion is for insertion into the battery holding space of any one of a plurality of cordless power tools. The fitting portion receives the DC voltage received through the cord and supplies the DC voltage to a cordless power tool in which the fitting portion is properly inserted. The voltage setting unit is for setting voltage supplied through the fitting portion to the cordless power tool. The fitting prevention mechanism operates in linked association with operation of the voltage setting unit to prevent proper insertion of the fitting portion into a cordless power tool that has a rated voltage different from the voltage set by the voltage setting unit.

Adapter for DC power source unit

Growing community of inventors

Hitachinaka, Japan

Takeshi Takeda