Power tool

A power tool for driving a tool implement comprising:

• a tool body;
• a driving motor incorporated in the tool body and having an output shaft;
• means incorporated in the tool body for operating the driving motor;
• a speed reduction gear mechanism including a plurality of stages of planetary gear sets for transmitting a driving force of the driving motor through the planetary gear sets to a tool implement to drive the same, wherein said planetary gear sets include a slide gear member axially movable between a forward position and a rearward position, said slide gear member being provided with an internal gear to be meshed with one of the gears constituting the planetary gear sets to change rotating speed of the tool implement;
• a resilient support ring in the shape of a circular ring, integrally formed with a slide lever, to rotatably support said slide gear member, said slide lever being disposed axially movably relative to the tool body;
• engaging means disposed between the slide lever and the tool body for selectively holding the slide lever at either one of a forward position or a rearward position against the tool body for changing a rotating speed of the tool implement;
• said resilience support ring being sufficiently resiliently deformed in an axial direction of said tool body when said slider lever is held by the engaging means at the forward position and the slide gear member is not meshed with the one of gears constituting the planetary gear sets such that the slide gear is automatically shifted in a direction opposite to a deformed direction to engage with said one of the gears constituting the planetary gear sets when the driving motor is started to drive;
• and
• said resilience support ring being sufficiently resiliently deformed in an axial direction of said tool body when said slider lever is held by the engaging means at the rearward position and the slide gear member is not meshed with the tool body such that the slide gear member is automatically shifted in a direction opposite to a deformed direction to engage the slide gear member with the tool body when the driving motor is started to drive.