Oscillating armature motor for electric razor - in which resonance is adjustable for 50 or 60 hz operation

摘要

The oscillating armature is linked with tuned return springs to give resonance at a particular frequency. The springs have a non-linear of progressive characteristic, and the resonant frequency is determined by the degree of pretensioning of the springs. Typically coil springs with progressive pitch are employed. These are attached to the case of the razor by a screw mounting so that movement of the screw from one extreme position to the other selects resonance at either 50 or 60 Hz.