Hitachi Koki Co., Ltd.

Jyunichi Toukairin

Shinki Ohtsu

Kenji Kataoka

Hideki Watanabe

Takuma Saito

Kazuhide Ohzeki

Shigeru Ishikawa

An impact drill for boring a workpiece includes a main frame, a motor housed in the main frame, a spindle movably supported by the main frame and rotatable by the motor and movable in its axial direction, a first ratchet positioned fixedly with respect to the spindle, a second ratchet positioned with respect to the first ratchet, a spring biasing the second ratchet toward the first ratchet. The spring has at least one of a spring constant and a biasing force which prevents the second ratchet and the spindle from abutting against the main frame at least one of when a force ranging from 15 to 25 kg is applied to the main frame for boring the workpiece and when the spindle is moved to a retracted position.

Impact drill

An impact drill minimizing transmission of vibration to a handle gripped by a user's hand. A spindle extends through a main frame and is movable in its axial direction and rotatable about its axis. A first ratchet is rotatable and axially movable together with the spindle. A second ratchet is axially movable but unrotatable. In an impact drilling mode, the first ratchet is brought into abutment with the second ratchet so that the spindle is reciprocally moved in the axial direction.

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Hitachinaka, Japan

Jyunichi Toukairin