RECIPROCATING WORKPIECE DEVICE WITH A DRIVE SYSTEM SEEKING THE RESONANCE OF THE DRIVEN SYSTEM PORTION THEREOF

• US 20100186179A1
• Filed: 06/30/2006
• Published: 07/29/2010
• Est. Priority Date: 06/30/2005
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Miller, Kevin, Benning, Wolter, Pace, John, Headstrom, Patrick
• Granted Patent: US 8,418,300 B2
• Time in Patent Office: Days
• US Class Current: 15/22.200
• CPC Class Codes: A61C 1/07 with vibratory drive, e.g. ultrasonic
• CPC Class Codes: A61C 17/34 driven by electric motor
• CPC Class Codes: H02K 49/108 with an axial air gap
• CPC Class Codes: H02K 7/06 Means for converting reciprocating motion into rotary motion or vice versa

Abstract

A workpiece system with a reciprocating motion which includes a motor assembly for producing an output drive signal with a periodic force pulse. The drive signal is coupled to a driven member assembly through a magnetic arrangement, wherein the driven member assembly has a workpiece mounted thereon with a return spring assembly. The driven member assembly has a resonant mechanical frequency. As the RPM of the motor increases from zero following startup, the drive signal frequency increases to the point very near resonance, where the energy from the drive signal is transferred into the reciprocating motion of the driven assembly, producing an effective amplitude of workpiece motion.

Claims

1. A workpiece system having a reciprocating action, comprising:

a drive assembly producing an output drive signal comprising periodic force pulses, resulting in a drive frequency which increases from zero in operation of the drive assembly; and

a driven member assembly having a workpiece mounted thereon with a return spring assembly, the driven member assembly having a resonant frequency, wherein, as the drive frequency increases from zero, it will approach the resonant frequency of the driven assembly, wherein at approximately said resonant frequency, at least a substantial portion of energy produced by the drive assembly is transferred into the movement of the workpiece, producing an effective workpiece action.

2. The system of claim 1, wherein further increases in energy produced by the drive assembly at said approximately resonant frequency are transferred into movement of the workpiece, for a range of increase in energy, thereby locking in energy increases to increases in workpiece movement.

3. The system of claim 1, wherein the drive assembly includes a DC motor with an output shaft which rotates in operation.

4. The system of claim 1, wherein the workpiece is a personal care device.

5. The system of claim 1, wherein the workpiece is an oral care device.

6. The system of claim 4, wherein the oral care device is a toothbrush.

7. The system of claim 3, wherein the system includes a magnetic coupling arrangement between the drive system and the driven system.

8. The system of claim 7, wherein the drive system includes a first hub member attached to the output shaft from the DC motor and at least one magnet mounted on a forward surface thereof, and wherein the driven system includes a second hub member mounted on a driven system shaft and at least one magnet mounted on a rear surface thereof, such that as the first hub member rotates, the magnet thereon slips past the magnet on the second hub, producing force pulses to the driven system.

9. The system of claim 8, including a plurality of magnets on the first hub member and a plurality of magnets on the second hub member.

10. The system of claim 7, wherein the drive system includes a first hollow cylindrical hub member attached to the output shaft from the DC motor and a plurality of magnets mounted on an internal surface thereof, and wherein the driven system includes a second cylindrical hub member which fits into the first hub member, the second cylindrical hub member including armature elements which result in coupling between the first and second hubs in operation.

11. The system of claim 10, including magnets positioned on the armature elements.

12. The system of claim 1, wherein the drive system includes a first hub member attached to the output shaft from the DC motor and at least one magnet mounted on a forward surface thereof, and wherein the driven system includes a second hub member mounted on a driven system shaft and a steel member mounted on the driven system shaft, in operation producing a reluctance coupling between the drive and driven system.

13. The system of claim 1, wherein the system includes a viscous coupling assembly between the drive system and the driven system, the viscous coupling assembly including first and second members with spaced vanes, facing each other in a housing with a viscous fluid, such that as the drive system moves one member with vanes, movement of the second member with vanes occurs by virtue of the vanes on the first member slipping past the vanes on the second member in the viscous fluid.

14. The system of claim 1, wherein the spring assembly includes a centering node element and two torsional springs on either side thereof operating in countermotion, wherein the node element is secured to a housing for the workpiece system.

15. The system of claim 1, wherein the spring assembly includes a torsional spring member and a balance mass, the torsional spring being secured to a housing for the workpiece system.

16. The system of claim 3, including a power control assembly providing an adjustable level of power to the motor, thereby providing the capability of changing the amplitude of movement of the workpiece assembly when the system is operating at approximately resonance.

17. The system of claim 1, wherein the driven assembly is mounted so as to have more than one mode of movement, and wherein the modes of movement and the resonant frequencies thereof are selected and determined that a single drive frequency can excite both modes of movement.

18. The system of claim 1, wherein the driven assembly is mounted so that the workpiece thereon rotates through a selected arc.

19. The system of claim 1, wherein the driven assembly is mounted so that the workpiece moves axially.

20. The system of claim 1, wherein the driven assembly is mounted so that the workpiece moves back and forth through a selected arc.

21. The system of claim 11, wherein the modes of movement include both axial and rotational movement.

22. The system of claim 1, including means using the action of the drive assembly for pumping a fluid to the workpiece in addition to moving the driven assembly.

23. The system of claim 1, wherein the system adapts automatically to changes in the resonant frequency of the driven assembly over time.

24. The system of claim 1, wherein the drive system is adapted to drive other elements besides said driven system on which a workpiece is mounted.

25. The system of claim 1, wherein the workpiece is a toothbrush.

26. The system of claim 1, wherein the system adapts automatically to changes in the resonant frequency of the driven assembly, including change of the workpiece.

27. A workpiece system having a reciprocating action, comprising:

a drive assembly, including a DC motor with an output shaft, a first hub member attached to the output shaft, and at least one magnet positioned on a first hub member surface thereof; and

a driven assembly having a workpiece mounted thereon, the driven assembly including a second hub member mounted on a driven system shaft and at least one magnet mounted on a second hub member surface thereof, such that when the first hub member rotates by action of the motor, the magnets on the first hub member surface slip past the magnet on the second hub member surface, producing force pulses to the driven system.

28. The system of claim 27, including a plurality of magnets on the first hub and a plurality of magnets on the second hub.

29. The system of claim 27, wherein the first hub member surface is forward-facing and the second hub member surface is rear-facing.

30. The system of claim 27, wherein the first hub member is a hollow cylinder and the first hub member surface is an interior surface thereof, and wherein the second hub member fits into the first hub member and the second hub member surface is an exterior surface thereof, such that the magnets on the first hub member surface can come into alignment with the magnets on the second hub member surface.

31. The system of claim 27, wherein the workpiece is a toothbrush.

32. The system of claim 27, including a spring return system, wherein the driven assembly includes two magnets, spaced approximately 180°

apart, having the same polarity, wherein the drive assembly has four magnets spaced 90°

apart, at least two of which are spaced 180°

apart and have the same polarity as the driven magnets.

33. The workpiece system of claim 27, including two startup magnets mounted approximately 180°

apart and having a polarity which balances the polarity of the magnets on the first hub.

34. The system of claim 27, wherein the magnets on the second hub form a ring, the ring of magnets comprising individual magnet segments with alternating polarity.

35. A dental hygiene device for cleaning teeth, comprising:

a drive assembly producing an output drive with a period force pulse, resulting in a drive frequency which gradually increases from zero in operation of the drive assembly, wherein the drive assembly includes a battery powered DC motor; and

a driven assembly having a brushhead mounted thereon with a return spring assembly, the driven assembly having a resonant frequency, and wherein as the drive frequency increases from zero, the drive frequency will approach the resonant frequency of the driven assembly, at which point the energy produced by the motor is transferred into movement of the brushhead, such that the tips of the bristles of the brushhead move at a velocity greater than approximately 1.5 meters per second, sufficient to produce a cleansing action on the teeth.

36. The device of claim 35, characterized by a lack of electronic control elements, except for an on-off switch.

37. The device of claim 35, wherein the batteries are replaceable.