Antilash driving apparatus for rotating a spindle or a work piece receiving member of a machining apparatus

An electroerosive machining apparatus, comprising:

• a spindle or a workpiece receiving means;
• a reversible electric motor;
• reduction gear means associated with said electric motor including an input member operatively connected to said electric motor and driven by said electric motor as well as an output member operatively connected to the spindle or the work piece receiving means of the electroerosive machining apparatus;
• an angular position sensing means operatively connected to the spindle or the work piece receiving means of the electro erosive machining apparatus;
• control means including power supply means operatively connected to said electric motor as well as to said angular position sensing means;
• said input member comprising a pinon member and said output member comprising a first gear wheel means and a second gear wheel means, said first and second gear wheel means being rotatable with reference to each other and both meshing with said pinion member;
• said first gear wheel means being torsionally fixedly connected to the spindle or the work piece receiving means of the electro erosive machining apparatus, and said second gear wheel means being rotatable with reference to said first gear wheel means;
• and
• further comprising means to bias said second gear wheel means to perform a rotation with reference to said first gear wheel means.