Abstract: A power tool includes a motor and a gear speed reducer. The motor has a motor shaft that is rotatable in a normal direction and in a reverse direction. The gear speed reducer is operably coupled to the motor shaft. The gear speed reducer is configured such that a reduction ratio of the gear speed reducer is changed in response to a change of a rotation direction of the motor shaft.

Abstract: A power tool includes a motor, a speed reducer and a speed-reducing-ratio change mechanism. The speed reducer includes planetary gear mechanisms arranged in multiple stages. The speed-reducing-ratio change mechanism is configured to change a speed reducing ratio of the speed reducer in response to a change of a rotating direction of a motor shaft. At least two stages of the planetary gear mechanisms are configured such that an internal gear in each stage selectively functions as a fixed element. The speed-reducing-ratio change mechanism includes a one-way clutch and a lock mechanism configured to non-rotatably lock the internal gears of the at least two stages when the one-way clutch does not transmit rotation, and to rotate the internal gears of the at least two stages when the one-way clutch transmits rotation. The at least two stages include a speed-increasing planetary gear mechanism and a speed-reducing planetary gear mechanism.

Abstract: A reciprocating tool easily supplies a lubricant, such as grease (lubricating oil), to a mechanism for reciprocating a slider, and prevents a lack of lubricant. A reciprocating saw as a reciprocating tool includes a motor, a reciprocating conversion mechanism that converts rotation of the motor to reciprocation, a slider connected to the reciprocating conversion mechanism and being reciprocable, and a slider guide that supports the slider in a reciprocable manner and includes a lubricant-passage member in contact with the slider to allow passage of at least part of a lubricant through the lubricant-passage member, and a lubricant reservoir located adjacent to the lubricant-passage member to store the lubricant.

Abstract: A power tool includes a motor and a gear speed reducer. The motor has a motor shaft that is rotatable in a normal direction and in a reverse direction. The gear speed reducer is operably coupled to the motor shaft. The gear speed reducer is configured such that a reduction ratio of the gear speed reducer is changed in response to a change of a rotation direction of the motor shaft.

Abstract: A reciprocating tool easily supplies a lubricant, such as grease (lubricating oil), to a mechanism for reciprocating a slider, and prevents a lack of lubricant. A reciprocating saw as a reciprocating tool includes a motor, a reciprocating conversion mechanism that converts rotation of the motor to reciprocation, a slider connected to the reciprocating conversion mechanism and being reciprocable, and a slider guide that supports the slider in a reciprocable manner and includes a lubricant-passage member in contact with the slider to allow passage of at least part of a lubricant through the lubricant-passage member, and a lubricant reservoir located adjacent to the lubricant-passage member to store the lubricant.

Abstract: An attachment includes a planetary reducer, a reaction force receiving member, and a universal joint. The planetary reducer has a first output shaft and a second output shaft connectable to a socket. The reaction force receiving member is connected to the first output shaft and has an arm part for contact with an external contact object. The universal joint has an input-side end part connectable to a final output shaft of a fastening tool and an output-side end part connected to the planetary reducer. The reaction force receiving member is configured to rotate integrally with the first output shaft in a direction opposite to the second output shaft by a reaction force caused by rotation of the socket. The universal joint is configured to transmit the torque inputted from the final output shaft via the input-side end part, to the planetary reducer via the output-side end part.

Abstract: A reciprocating saw serving as reciprocating tool is equipped with a motor, a drive transmission mechanism that converts rotation of the motor into reciprocating motion, a rod that is connected to the drive transmission mechanism and that engages in reciprocating motion, and an upper roller and a lower roller that are capable of rolling and that have depressed portions that are capable of coming in contact with the rod, wherein the cross-section of the rod has no corners, and the depressed portions of the upper roller and the lower roller have hourglass-like profiles.

Abstract: An attachment includes a planetary reducer, a reaction force receiving member, and a universal joint. The planetary reducer has a first output shaft and a second output shaft connectable to a socket. The reaction force receiving member is connected to the first output shaft and has an arm part for contact with an external contact object. The universal joint has an input-side end part connectable to a final output shaft of a fastening tool and an output-side end part connected to the planetary reducer. The reaction force receiving member is configured to rotate integrally with the first output shaft in a direction opposite to the second output shaft by a reaction force caused by rotation of the socket. The universal joint is configured to transmit the torque inputted from the final output shaft via the input-side end part, to the planetary reducer via the output-side end part.

Abstract: A reciprocating saw serving as reciprocating tool is equipped with a motor, a drive transmission mechanism that converts rotation of the motor into reciprocating motion, a rod that is connected to the drive transmission mechanism and that engages in reciprocating motion, and an upper roller and a lower roller that are capable of rolling and that have depressed portions that are capable of coming in contact with the rod, wherein the cross-section of the rod has no corners, and the depressed portions of the upper roller and the lower roller have hourglass-like profiles.