motorised handpiece , more particularly for used by dentists or dental technicians , the rotary movement of a motor being transmitted to a tool which can be clamped with the aid of a clamping mechanism . to this end , the rotary movement of the motor is transmitted via an integrally formed shaft to the clamped tool , both the motor and the clamping mechanism being mounted on this integrally formed shaft . as a result of the use of an integrally formed shaft , it is possible to dispense with superfluous ball bearings for mounting the shaft and no mechanical driver system is required in order to couple two separate shafts together , for example .