| 摘要 |
<p>The toothbrush has the miniature electric motor contained within a casing which is held in the hand and used to rotate two drive shafts in opposite directions. A removable unit incorporating a brush roller can be fitted to each drive shaft, so that the brush rollers rotate adjacent one another in opposite directions, for brushing the front and back surfaces of the teeth respectively. Pref. each of the brush rollers is enclosed by a surrounding cylinder with a rounded closed end and an axial slot on the side where the two rollers face towards one another. The two bursh rollers may be fitted closely to the casing containing the electric motor or they may be fitted to the extreme ends of two extended drive shafts projecting from the casing.</p> |
