US 7,315,098 B2 · Linear oscillator and electrically driven toothbrush

Abstract

A linear oscillator and an electric toothbrush capable of emitting a low noise and of being assembled compact are provided. The linear oscillator, which reciprocates a shaft in an axial direction thereof, includes a plunger movable together with the shaft in the axial direction of the shaft, an elastic member for applying an axially acting resilient force to the plunger, an electromagnetic driving unit operable to reciprocate the plunger in the axial direction of the shaft at a resonant frequency when an alternating current is supplied thereto, and a fixing member restricting rotation of the plunger about an axis thereof within a predetermined angle. The electric toothbrush includes the linear oscillator and a brush head attached to the shaft for use in brushing teeth.

Claims17

Dependent claims

A linear oscillator for reciprocating a shaft in an axial direction of the shaft, comprising:

a case;
a plunger disposed in the case so as to be movable together with the shaft in the axial direction of the shaft;
an elastic member acting in the axial direction of the shaft for applying a resilient force to the plunger;
an electromagnetic driving unit operable to reciprocate the plunger in the axial direction of the shaft at a resonant frequency when an alternating current is applied thereto;
the elastic member comprising a coil spring having first and second opposite ends, the first end being fixed with the case and the second end being fixed with the plunger to impart rotation to the shaft about the axis of the shaft within a predetermined angular range concurrently with an axial expansion or contraction of the coil spring caused by the reciprocation of the plunger.

2 more elements

An electric toothbrush having a linear oscillator for reciprocating a shaft in an axial direction of the shaft and a brush head attached to the shaft for use in brushing teeth, the linear oscillator comprising:

a case;
a plunger disposed in the case so as to be movable together with the shaft in the axial direction of the shaft;
an elastic member acting in the axial direction of the shaft for applying a resilient force to the plunger;
an electromagnetic driving unit configured for reciprocating the plunger in the axial direction of the shaft at a resonant frequency when an alternating current is applied thereto;
the elastic member comprising a coil spring having first and second opposite ends, the first end being fixed with the case and the second end being fixed with the plunger to impart rotation to the shaft about the axis of the shaft within a predetermined angular range concurrently with an axial expansion or contraction of the coil spring caused by the reciprocation of the plunger.

2 more elements

Dependencies are inferred from the claim text.

Linear oscillator and electrically driven toothbrush

Life of this patent

Linear oscillator and electrically driven toothbrush

Life of this patent

Abstract

Claims17