Load sensing for oral devices

Patent metadata

Field	Value
Publication number	US-10561480-B2
Application number	US-201715588842-A
Country	US
Kind code	B2
Filing date	May 8, 2017
Priority date	May 9, 2016
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

A toothbrush is disclosed. The toothbrush includes a handle, a brush tip connected to the handle, wherein the brush tip includes a plurality of bristles operably connected thereto, a power source, a direct current motor in selective electrical communication with the power source, wherein the motor includes a drive shaft, a drive assembly connected between the brush tip and the drive shaft, wherein the drive assembly converts rotation of the drive shaft into movement of the plurality of bristles, and a control assembly in electrical communication with the motor and the power source; wherein during operation of the motor, the control assembly monitors a current draw by the motor and adjusts a current applied to the direct current motor based on the current draw.

First claim

What is claimed is:

1. A toothbrush comprising:
a handle;
a brush tip connected to the handle, wherein the brush tip includes a plurality of bristles operably connected thereto;
a power source;
a direct current motor in selective electrical communication with the power source, wherein the motor includes a drive shaft;
a drive assembly connected between the brush tip and the drive shaft, wherein the drive assembly converts rotation of the drive shaft into movement of the plurality of bristles; and
a control assembly in electrical communication with the motor and the power source; wherein
after activation of the motor, the control assembly determines an initial current draw by the motor to determine a no-load condition of the motor; and
once the initial current draw is determined and the motor continues to operate, the control assembly monitors an operating current draw by the motor and adjusts a current applied to the direct current motor based on comparison of a delta between the initial current draw and the operating current draw to a predetermined threshold.

2. The toothbrush of claim 1 , further comprising an output element in communication with the control assembly.

3. The toothbrush of claim 2 , wherein when the delta between the initial current draw and the operating current draw exceeds the predetermined threshold, the output element provides an output to the user.

4. The toothbrush of claim 1 , wherein the control assembly comprises one or more sensing modules that detect a current provided to the direct drive motor.

5. The toothbrush of claim 4 , further comprising a field effect transistor coupled to the control assembly and the direct drive motor that modulates the current provided to the direct drive motor based on the detected current.

6. A toothbrush comprising:
a brush tip comprising a plurality of bristles operably coupled thereto;
a driver that actuates movement of the brush tip, the plurality of bristles, or a combination thereof;
a power source that provides current to the driver;
a sensing module that detects an initial current provided to the driver within a no-load window after startup and that detects an operating current provided to the driver during normal operation; and
a controller coupled to the driver and the sensing module, wherein the controller dynamically adjusts a provided current to the driver based on a comparison of a delta between the initial current provided to the driver within the no-load window and the operating current provided to the driver during normal operation to a predetermined current threshold, wherein the comparison determines an adjustment to the current provided to the driver.

7. The toothbrush of claim 6 , wherein the detected current is proportional to a pressure applied to the plurality of bristles.

8. The toothbrush of claim 6 , further comprising a transistor coupled between the power source and the motor, wherein the sensing module comprises a signal amplifier that detects a drain-source voltage of the transistor.

9. The toothbrush of claim 8 , wherein the controller adjusts the provided current to the driver by dynamically adjusting a gate condition or a channel condition of the transistor.

10. The toothbrush of claim 6 , wherein the controller provides an alert to a user responsive to the delta exceeding the current threshold.

11. A method of operating a toothbrush comprising:
determining an initial current provided to a motor driving a plurality of bristles on a brush tip wherein the initial current is determined prior to applying any pressure to the plurality of bristles;
detecting, by a sensing module, a current provided to the motor, wherein the detected current is proportional to a pressure applied to the plurality of bristles and the detected current is determined relative to the initial current;
determining, by a processor, a delta between the detected current and the initial current;
determining, by the processor, whether the delta exceeds a threshold current; and
responsive to determining that the delta exceeds the threshold current, providing an alert to a user responsive to determining that the delta exceeds the threshold or dynamically adjusting one of a current or a voltage provided to the motor.

12. The method of claim 11 , wherein the initial current is determined within 50 ms of activating the motor.

13. The method of claim 11 , wherein dynamically adjusting the current or the voltage provided to the motor comprises adjusting a rheostat coupled between a power source and the motor.

14. The method of claim 11 , wherein dynamically adjusting one of a current or a voltage provided to the motor comprises modulating a transistor coupled between the motor and a power source providing current to the motor.

15. The method of claim 14 , wherein detecting the current provided to the motor comprises amplifying a signal detected across the transistor to provide an output signal to the processor.

16. The method of claim 11 , wherein dynamically adjusting one of the current or the voltage provided to the motor further comprises reducing the one of the current or the voltage provided to the motor.

17. The method of claim 16 , wherein reducing the one of the current or the voltage provided to the motor further reduces the pressure applied to the plurality of bristles.

18. The method of claim 11 , wherein the motor includes a drive shaft operably coupled to the brush tip to translation motion of the drive shaft into movement of the brush tip.

19. The method of claim 11 , wherein determining that the delta exceeds a threshold current comprises comparing the delta to a linear pressure-current relationship for the motor.

20. The method of claim 19 , wherein the linear relationship takes into account one or more of the following: bristle strand thickness, tuft height, or tuft counts.

Assignees

• Water Pik Inc

Inventors

• Luettgen Harold A
• Fiers John
• Williams Brian R

Classifications

• G01L5/22

  for measuring the force applied to control members, e.g. control members of vehicles, triggers · CPC title

• A61C17/3436

  Rotation around the axis perpendicular to the plane defined by the bristle holder · CPC title

• A61C17/24

  rotating continuously (A61C17/40 takes precedence) · CPC title

• A46B15/0012

  with a pressure controlling device · CPC title

• A61C17/3418

  Rotation around the axis of the toothbrush handle · CPC title