G04C3/00—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means
G04C3/04—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a balance
G04C3/042—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a balance using mechanical coupling