| 摘要 |
An ultrasonic dental scaler for use with a dental scaler insert having a resonant frequency associated therewith includes a handpiece adapted for removably receiving the dental scaler insert, an energizing coil mounted on the handpiece, whereby the energizing coil substantially surrounds the dental scaler insert. The ultrasonic dental scaler includes a selectively tunable oscillator circuit coupled to the energizing coil and which generates a control signal having an oscillation frequency associated therewith for vibrating the dental scaler insert in response thereto. Specifically, the selectively tunable oscillator circuit includes an automatic tuner for automatically altering the oscillation frequency associated with the control signal to be substantially equivalent to the resonant frequency associated with the dental scaler insert in response to the control signal being fed back thereto. Further, the selectively tunable oscillator circuit includes a manual tuner for altering the oscillation frequency associated with the control signal in response to manual adjustment of the manual tuner. The selectively tunable oscillator circuit also includes a switch which is operatively coupled to the automatic and manual tuners and the oscillator circuit and which selectively switches control of the alteration of the oscillation frequency between the automatic and manual tuners. The ultrasonic dental scaler may also include an offset adjustment circuit operatively coupled to the oscillator circuit for manually adjusting the oscillation frequency so that the oscillation frequency may be selectively offset therefrom to an adjusted oscillation frequency while in the automatic tune mode. The ultrasonic dental scaler may also include both a coarse and fine frequency control for adjusting the oscillation frequency while in the manual tune mode.
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