Method for detecting transverse mode vibrations in an ultrasonic hand piece/blade
AssigneeEthicon Endo-Surgery, Inc.
InventorsJames R. Giordano, Foster B. Stulen
Life of this patent
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Abstract
A method for detecting transverse mode vibrations in an ultrasonic hand piece/blade for determining the existence of unwanted vibration in the hand piece/blade. A tracking filter centered at the drive frequency of the generator, is used to monitor the drive frequency of the ultrasonic generator and attenuate the drive signal when it exceeds a predetermined level. The tracking filter has a wide pass band. Alternatively, a tracking filter having a pass band which is divided into several regions is used to avoid other longitudinal resonances, such as a resonance at a second harmonic, or other spectral features that would otherwise detract from the tracking accuracy of the filter.
Claims22
A method for detecting transverse vibrations in an ultrasonic hand piece/blade, comprising:
- applying a drive signal to the hand piece/blade using an ultrasonic generator;
- monitoring a change over time of the drive signal;
- measuring a level of an output signal from a filter located in the ultrasonic generator;
- comparing the output signal to a predetermined level;
- and
- if the output signal exceeds the predetermined level, displaying a message on a liquid crystal display of the generator to indicate that the ultrasonic hand piece/blade contains transverse vibrations.
A method for detecting transverse vibrations in an ultrasonic hand piece/blade, comprising:
- applying a drive signal to the hand piece/blade using an ultrasonic generator;
- monitoring a change with respect to load of a rms value of an output signal from a filter;
- comparing the change with respect to load of the rms value output from the filter to a predetermined level;
- and
- displaying a message on a display, if the rms value exceeds the predetermined level to indicate that the ultrasonic hand piece/blade contains transverse vibrations.
Dependencies are inferred from the claim text.