Patent ID: 8505415

Claim:
A power tool, comprising: a housing; a rotation motor; a reduction gearing; an output shaft; and a separate gearing casing carried on the housing and supporting the output shaft; wherein: said reduction gearing comprises a first gearing stage disposed in the housing, a second gearing stage disposed in the gearing casing, and a torque sensing device associated with said first gearing stage and arranged to indicate a torque corresponding to a torque delivered via the output shaft; the gearing casing together with said second gearing stage form a separate gearing unit which is detachably connected to the housing; said first gearing stage is connected to said second gearing stage via an intermediate spindle; said motor is connected to said first gearing stage via a drive shaft; said drive shaft is tubular and surrounds co-axially said intermediate spindle, and the motor is coupled to said drive shaft via an angle gear; said first gearing stage includes a planetary gearing with a ring gear coupled to the housing; and said torque sensing device includes a torque transferring element coupling said ring gear to the housing and arranged to be elastically deformable under a reaction torque load applied on said ring gear, and a strain gauge sensor attached to said torque transferring element and arranged to deliver electric signals in response to the reaction torque transferred to the housing via said torque transferring element.