System and method for maintaining performance of battery-operated toothbrushes
US8368327B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 2007 |
| Grant date | Feb 5, 2013 |
| Priority date | — |
| Expiry date | Sep 22, 2029 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61C17/221
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
The system periodically measures the battery voltage of the toothbrush and the current in a stator portion of the motor for the appliance. The amplitude of movement of the toothbrush workpiece is determined from the measured stator current. A circuit/control program changes the duty cycle or pulse width of the drive signal from the motor if the battery voltage drops below a first threshold value and a circuit or control program changes the drive frequency of the appliance if the amplitude of the workpiece movement falls below a first threshold value. A circuit/control program terminates the operation of the toothbrush if the voltage drops below a second threshold value or if the amplitude drops below a second threshold value, both of which are less than the respective first thresholds.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.