Changing amplitude of movement by changing the drive frequency of a toothbrush brushhead

• US 7,979,938 B2
• Filed: 12/09/2004
• Issued: 07/19/2011
• Est. Priority Date: 12/15/2003
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Pace, John W., Lilley, Ronald C., Bryant, William E., Grez, Joseph W., Hall, Scott E.
• Primary Examiner(s): Carter; Monica S
• Assistant Examiner(s): NEWTON, STEPHANIE R
• Application Number:
  US10/582,837
• Publication Number:
  US 20080168611A1
• Time in Patent Office: 2,413 Days
• Field of Search: 15/221
• US Class Current: 15/22.1
• CPC Class Codes: A61C 17/22 with brushes, cushions, cups, or the like brush bodies, e.g. arrangements of the bristles A46B
• CPC Class Codes: A61C 17/221 Control arrangements therefor
• CPC Class Codes: A61C 17/32 reciprocating or oscillating
• CPC Class Codes: H02P 25/032 Reciprocating, oscillating or vibrating motors

Abstract

The drive system drives a brushhead at a driving frequency. The drive system includes a frequency modulation system which changes. the driving frequency about a center frequency in such a manner, with selected frequency deviation and modulation frequency, which interacts with the resonance of the brushhead to produce a change of amplitude in the movement of the brushhead within a range of 5-30%.

Claims

1. A system for resonantly driving a power toothbrush having a resonant frequency, wherein a brushhead portion of the toothbrush moves in operation through a path with an amplitude about a center point, comprising:

a resonant drive system for driving a brushhead at a drive frequency, the drive system including a circuit for changing the drive frequency to produce a predetermined regularly varying drive frequency relative to a center frequency to produce a regularly varying amplitude of the brushhead portion within the range of 5-30%, providing an improved sensory experience without discomfort to the user.

2. The system of claim 1, wherein the change of amplitude is less than 20%.

3. The system of claim 1, wherein the center frequency is different from the resonant frequency of the toothbrush within a range of 0 to 5 Hz.

4. The system of claim 3, wherein the changing of the drive frequency is accomplished by frequency modulation.

5. The system of claim 4, wherein the difference between the center frequency and the resonant frequency is approximately ±

3 Hz.

6. A system of claim 1, wherein the driving frequency has a frequency deviation with a range of 1-14 Hz from the center frequency.

7. The system of claim 6, wherein the frequency deviation is approximately 3.5 Hz.

8. The system of claim 1, wherein the driving frequency change has a modulation frequency within the range of 3-40 Hz.

9. The system of claim 8, wherein the modulation frequency is approximately 12 Hz.

10. The system of claim 4, wherein the change of the drive frequency is in the form of a triangular wave.

11. The system of claim 1, wherein the change of drive frequency has a duty factor of approximately 48%.

12. The system of claim 1, wherein the drive system includes two driving signal sources, one signal source being at approximately the resonant frequency and the other signal source being at a frequency which is slightly different than the resonant frequency.

13. The system of claim 12, wherein the frequency of the second signal source is different than the frequency of the first source within a range of 5 to 30 Hz.