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Method for detecting a loose blade in a hand piece connected to an ultrasonic surgical system

  • US 6,537,291 B2
  • Filed: 05/31/2001
  • Issued: 03/25/2003
  • Est. Priority Date: 10/20/2000
  • Status: Expired due to Term
First Claim
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1. A method for detecting a loose blade in a hand piece connected to an ultrasonic surgical system, comprising the steps of:

  • exciting the hand piece with a high level drive signal using an ultrasonic generator;

    performing multiple frequency sweeps of the hand piece across a predetermined frequency range;

    measuring resonance frequencies of the hand piece during the multiple frequency sweeps at which minimum impedance of the hand piece occur;

    storing the measured resonance frequencies of the hand piece at which minimum impedance occurs;

    comparing the stored resonance frequencies to determine whether a difference between the stored resonance frequencies exceeds a predetermined threshold; and

    if the difference between the stored resonance frequencies exceeds the predetermined threshold, displaying a message on a liquid crystal display of the generator.

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