Apparatus (26) for converting side-to-side drive movement into rotary movement for a part (20, 94) of a workpiece of an electrical apparatus (10, 80), comprising: an element (40, 81, 120 ) mobile base assembly, which can be operated in an alternative movement from side to side； a fixed position mounting element (64, 88, 138) separated from the movable base mounting element (40, 81, 120), wherein the fixed position mounting element (64, 88, 138) is held in position so that it does not move during operation of the device； a spring element (60, 62； 84, 86； 128, 130) extending between the fixed position mounting element (64, 88, 138) and the mobile base mounting element (40, 81, 120) and fixedly connected on one side to the fixed position mounting element (64, 88, 138) and on the other side mounted on the mobile base mounting element (40, 81, 120)； and a drive shaft element (28, 90, 129) connected to the mobile base mounting element (40, 81, 120) and rotatably disposed with respect to the fixed position mounting element (64, 88, 138) , the drive shaft (28, 90, 129) having a workpiece mounted thereon； wherein the spring element (60, 62, 84, 86, 128, 130) is configured and arranged such that it is substantially less resistant to a torsional action than to a bending action to produce a rotation of the element of drive shaft in response to a driving force from side to side to produce rotation of the workpiece at a preselected frequency, characterized in that the spring element (60, 62, 84, 86, 128, 130) comprises two springs of sheets or two springs of orthogonal wire shapes.Aparato (26) para convertir movimiento de accionamiento de lado a lado en movimiento rotatorio para una parte (20, 94) de una pieza de trabajo de un aparato (10, 80) eléctrico, que comprende: un elemento (40, 81, 120) de montaje de base móvil, que puede accionarse en un movimiento alternativo de lado a lado； un elemento (64, 88, 138) de montaje de posición fija separado del elemento (40, 81, 120) de mon
