Torque adjusting device for power driven rotary tools

Claim 1

A power driven rotary tool comprising: a housing including front and rear ends; an electric motor mounted within said housing adjacent the rear end thereof; a transmission shaft rotatably supported by said housing; a drive gear idly supported by said transmission shaft and operatively connected to said electric motor; a spindle rotatably mounted in said housing and including a portion extending through the front end of said housing; a plurality of speed change gears mounted on said spindle for selective driving engagement therewith; clutch means operably positioned on said transmission shaft and in generally confronting relation with said drive gear and between said drive gear and said speed change gears to selectively interconnect said drive gear and the selected speed change gear; a slider including front and rear ends axially movably fitted on said transmission shaft; a spring positioned between said slider and said clutch and adapted to urge said clutch toward said drive gear; and a manually-rotatable selector ring attached to the front end of said housing, said selector ring including a cam face positioned along a peripheral edge thereof and having a plurality of steps formed in a direction axially of said transmission shaft and engageable with said slider to selectively displace said slider in said axial direction for adjusting the axial position of said slider relative to said transmission shaft and amount of compression of said spring.