Apparatus and method for controlling excitation frequency of magnetostrictive ultrasonic device
US8295025B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Aug 19, 2009 |
| Grant date | Oct 23, 2012 |
| Priority date | — |
| Expiry date | Dec 24, 2030 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61C17/20
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Apparatus and method for controlling the frequency of the current in the excitation coil of a handpiece of a dental magnetostrictive ultrasonic scaling unit, or a similar transducer. A microprocessor continually samples predetermined functions of the current through the excitation coil, and periodically adjusts the frequency, by performing a coarse-stepped frequency scan, followed by a fine-stepped frequency scan until the function samples are close to predetermined optimum values. The functions can include the peak of the current and the peak of a high-pass filtered version of the current. The frequency adjustment is performed each time the handpiece is energized by the practitioner, and at frequent intervals thereafter, assuring automatic optimal frequency at all times and under all conditions. Apparatus according to the invention does not require sensing coils or complex power- or impedance-sensing circuitry and covers a wide range of resonant frequencies for different handpiece- and insert types. A configuration with multiple handpieces is supported.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.