The clutch has a sliding element (20) between contact surfaces of a sliding piece (18) and a smear head (12). A plate spring (26) is arranged at a spring space (19) of the piece between a sliding groove (16) and a blade (6), and lies at a region of the groove at the piece. A centering plate (27) is arranged adjacent to the spring at a side of the blade. The piece is pressed against a smear head holder (10) by a fastening screw (28), so that all components are wired with a motor shaft in a torque proof manner. The screw is reached through the plate, the spring and a fastening hole (15).
