Hitachi Koki Co., Ltd.

Hidekazu Harada

Nobuhiro Takano

Kenrou Ishimaru

Katsuhiro Oomori

Chikai Yoshimizu

Takao Aradachi

Takeshi Takeda

Kazuhiko Funabashi

Shigeru Shinohara

Yoshimasa Hayama

Daisuke Kakegawa

Syuichi Okada

A power tool includes a body housing a motor and a power transmission mechanism positioned ahead of the motor for transmitting a power of the motor, a handle grip having an upper end portion connected to an approximately intermediate portion of the body and a lower end portion to which a battery is connected, a light emitting element positioned below the power transmission mechanism and receiving electrical power from the battery for illuminating a portion ahead of the body, and a trigger positioned below the power transmission mechanism for controlling a supply of the electrical power from the battery to the motor and to the light emitting element.

Power tool

A power tool includes a motor as a drive power source, a body housing the motor and having an end output unit for chucking an end tool, a handle grip connected to the body; and a light unit disposed to one of the handle grip and the body, and having a light-emitting element for providing illumination near the end tool. The light unit comprises switch means for switching the light-emitting element on and off, and an off circuit for automatically turning the light-emitting element off at a predetermined time after the light-emitting element turns on.

Power tool with light unit

A dust collector includes: a motor functioning as a driving source; a drive unit for driving a motor; a dust collection fan rotated by the motor; a head section for accommodating the dust collection fan; a switch provided on the head section to control the starting of the motor; a tank section located below the head section, for accommodating dust conveyed by the dust collection fan, the tank section having a connecting portion; a duct hose having one end and the other end, the one end attached to the connecting portion, the other end being detachable from a portion of a power tool; a remote-control transmitter for transmitting a signal; and a remote-control receiver for receiving the signal from the remote-control transmitter to control the drive unit to start or stop the motor.

Dust collector

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 power tool has a light unit provided at the bottom part of the handle grip. The light unit can be adjusted to change the lighting angle and can hold the desired lighting angle. The light unit thus disposed does not get in the way, the lighting angle of the light unit is variable and the emitted light does not shake, depletion of the power supply due to the light switch of the light unit being left on is prevented, shadows of the end tool are not easily produced by light from the light unit, lighting contrast is high, wiring failures and continuity faults in the light-emitting element do not occur easily, and a small, economical power tool can be provided. The light-emitting element of the light unit is a yellow LED. The light unit turns off automatically at a predetermined time after the light turns on.

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

To provide a battery charger capable of fully charging both an active battery and an inactive battery, which have different charging characteristics near the peak level, a voltage across the battery is periodically sampled during charging the battery. A voltage change is obtained by subtracting a voltage that has been sampled previously from the newly sampled voltage. Determination of the fully charged condition of the battery is made when a voltage change falls below a critical value (S , S ) after identifying that the battery being charged is an active or inactive battery using another critical values (K , K or K &prime;, K &prime;). The critical values S and S and another critical values K and K (or K &prime; and K &prime;) are selectively referred to depending to the battery voltage change.

Growing community of inventors

Hitachinaka, Japan

Hidekazu Harada