Electric toothbrush and linear oscillator for the same

• US 20040010871A1
• Filed: 01/13/2003
• Published: 01/22/2004
• Est. Priority Date: 01/18/2002
• Status: Active Grant

• Current Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Asahi Matsushita Electric Works Ltd. (Panasonic Holdings Corporation)
• Inventors: Yamada, Tomio, Inoue, Hiroki, Nishinaka, Takahiro, Yabuuchi, Hidekazu
• Granted Patent: US 7,328,474 B2
• Time in Patent Office: Days
• US Class Current: 15/22.2
• CPC Class Codes: A61C 17/3445 Translation along the axis of the toothbrush handle
• CPC Class Codes: F16F 7/104 the inertia member being resiliently mounted F16F7/1022 takes precedence
• CPC Class Codes: H02K 33/16 with polarised armatures moving in alternate directions by reversal or energisation of a single coil system

Abstract

An electric toothbrush includes a drive part, a driver, a brush part and a vibration-absorber. The drive part includes a drive shaft provided to be lineally movable and a brush part detachably attached to one end of the drive shaft. The driver is configured to apply reciprocal force to the drive shaft to reciprocally lineally move the drive shaft. The vibration-absorber is connected to the drive shaft via a second spring to be lineally movable along the drive shaft. A weight ratio of a weight of the vibration-absorber to a weight of the drive part is at least 0.9 and at most 1.1.

Claims

1. An electric toothbrush comprising:

a drive part comprising;

a drive shaft provided to be lineally movable; and

a brush part detachably attached to one end of the drive shaft;

a driver configured to apply reciprocal force to the drive shaft to reciprocally lineally move the drive shaft;

a vibration-absorber connected to the drive shaft via a second spring to be lineally movable along the drive shaft; and

a weight ratio of a weight of the vibration-absorber to a weight of the drive part being at least 0.9 and at most 1.1.

2. An electric toothbrush according to claim 1, wherein the weight ratio is substantially equal to 1.0.

3. An electric toothbrush according to claim 1, wherein the driver comprises

a plunger fixed to the drive shaft;

first and second permanent magnets provided to provide magnetic power to the plunger; and

a coil provided between the first and second permanent magnets and facing the plunger.

4. An electric toothbrush according to claim 1, wherein the electric toothbrush comprises

first and second bearing supports to support the drive shaft;

a first spring provided between the first bearing support and the drive shaft; and

a third spring provided between the vibration-absorber and the second bearing support.

5. An electric toothbrush according to claim 1, wherein the electric toothbrush comprises a case comprising at least one projection projected inwardly to hold the driver.

6. A linear oscillator comprising:

a movable part including a drive shaft provided to be lineally movable;

a driver configured to apply reciprocal force to the drive shaft to reciprocally lineally move the drive shaft;

a vibration-absorber connected to the drive shaft via a second spring to be lineally movable along the drive shaft; and

a weight ratio of a weight of the vibration-absorber to a sum of a weight of the movable part and a weight of a brush part which is configured to be detachably attached to one end of the drive shaft being at least 0.9 and at most 1.1.

7. A linear oscillator according to claim 6, wherein the weight ratio is substantially equal to 1.0.

8. A linear oscillator according to claim 6, wherein the driver comprises a plunger fixed to the drive shaft;

first and second permanent magnets provided to provide magnetic power to the plunger; and

a coil provided between the first and second permanent magnets and facing the plunger.

9. A linear oscillator according to claim 6, wherein the linear oscillator comprises

first and second bearing supports to support the drive shaft;

a first spring provided between the first bearing support and the drive shaft; and

a third spring provided between the vibration-absorber and the second bearing support.

10. A linear oscillator according to claim 6, wherein the linear oscillator comprises a case comprising at least one projection projected inwardly to hold the driver.

11. A linear oscillator comprising:

a movable part including a drive shaft provided to be lineally movable;

driver means for applying reciprocal force to the drive shaft to reciprocally lineally move the drive shaft;

a vibration-absorber connected to the drive shaft via a spring to be lineally movable along the drive shaft; and

a weight ratio of a weight of the vibration-absorber to a sum of a weight of the movable part and a weight of a brush part which is configured to be detachably attached to one end of the drive shaft being at least 0.9 and at most 1.1.