MECHANICALLY DRIVEN RESONANT DRIVE POWER TOOTHBRUSH

• US 20120216358A1
• Filed: 10/15/2010
• Published: 08/30/2012
• Est. Priority Date: 11/16/2009
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Kloster, Tyler G.
• Granted Patent: US 8,863,344 B2
• Time in Patent Office: Days
• US Class Current: 15/22.2
• CPC Class Codes: A61C 17/3481 Vibrating brush body, e.g. by using eccentric weights

Abstract

The power toothbrush includes a handle (12) and a workpiece assembly (18) which includes a brushhead (20) at a forward end thereof. The toothbrush further includes a drive assembly (14) which includes a DC motor (26) having a rotating output shaft (41) and a mounting assembly (28) for flexibly mounting the motor to the handle. The drive assembly includes a torsion spring member (64), an eccentric member (52), a coupling member (44) for connecting the rotating output shaft of the motor to the rear end of the eccentric and a hub member (62) forward of the eccentric, wherein the other end of the eccentric extends to and is mounted to the hub member. The torsion spring extends between the motor mount and the hub member. In operation, the rotating eccentric excites a desired resonant mode in the torsion spring, resulting in a sweeping back and forth action of the workpiece assembly and the brushhead.

Claims

1. A power toothbrush, comprising:

a handle;

a workpiece assembly with a brushhead at the end thereof; and

a drive assembly for driving the workpiece assembly, including a motor having a rotating output shaft, a mounting assembly for the motor, a torsion spring member, an eccentric member, a coupling member for connecting the rotating output shaft of the motor and a rear end of the eccentric member, and a hub member, wherein the other end of the eccentric extends to and is mounted at the hub member and wherein the torsion spring extends between the motor mount and the hub member, wherein in operation, at a specific frequency, the rotating eccentric excites a desired resonant mode in the spring member, providing a sweeping back and forth action for the workpiece assembly and the brushhead.

2. The toothbrush of claim 1, wherein the motor is a DC motor, operating at 12,000-16,000 rpm with a torque of 0.5 mNewton-meters to 1.5 mNewton-meters.

3. The toothbrush of claim 1, wherein the torsion spring is a V-spring, with an included angle of between 50°

and 120°

, a length in the range of 20-60 mm and a spring rate in the range of 0.5 Newton-meters and 2 Newton-meters.

4. The toothbrush of claim 1, wherein the frequency of operation is 200-280 Hz, and wherein the amplitude of the brushhead is within the range of 7°

-20°

.

5. The toothbrush of claim 1, wherein the eccentric is a solid half-cylinder.

6. The toothbrush of claim 1, wherein the eccentric is loosely mounted in a bushing which in turn is mounted in the hub member.

7. The toothbrush of claim 1, including elastic members positioned between the motor mount and the handle, providing a flexible, energy-absorbing connection therebetween.

8. The toothbrush of claim 1, wherein the moment arm between the axis of the eccentric and the longitudinal axis of the brush arm is within the range of 5-11 mm.

9. A power toothbrush, comprising:

a handle;

a workpiece assembly with a brushhead at the end thereof; and

a drive assembly, including a motor assembly, a torsion spring member for driving the workpiece assembly, and an assembly for mechanically exciting the torsion spring in a desired resonant mode, providing a sweeping back and forth action of the brushhead.

10. The toothbrush of claim 9, wherein the motor is a DC motor having a rotating output shaft.

11. The toothbrush of claim 9, wherein the motor is a DC motor, operating at 12,000-16,800 rpm with a torque of 0.5 mNewton-meters to 1.5 mNewton-meters.

12. The toothbrush of claim 9, wherein the frequency of operation is 200-280 Hz, and wherein the amplitude of the brushhead is within the range of 7°

-20°

.

13. The toothbrush of claim 9, wherein the motor is mounted in a motor mount and wherein the drive assembly further includes elastic members positioned between the motor mount and the handle, providing a flexible, energy-absorbing connection therebetween.

14. The toothbrush of claim 10, wherein the spring exciting assembly includes an eccentric which rotates by action of the DC motor and wherein a moment movement arm between the eccentric axis of rotation and the longitudinal axis of the brush arm and force from the spinning eccentric results in sufficient torque to excite the torsion spring in a desired mode.