Electrosurgical instrument employing multiple positive temperature coefficient electrodes
First Claim
1. A surgical instrument, comprising:
- a handle; and
an end effector, comprising;
a first jaw;
a second jaw, wherein said first jaw is movable relative to said second jaw between an open position and a closed position;
a first electrode comprising a first positive temperature coefficient material interspersed throughout said first electrode, wherein said first positive temperature coefficient material comprises a first electrical resistance when the temperature of said first electrode is below a first switching temperature, and wherein said first positive temperature coefficient material comprises a second electrical resistance when the temperature of said first electrode is above said first switching temperature; and
a second electrode comprising a second positive temperature coefficient material interspersed throughout said second electrode, wherein said second positive temperature coefficient material comprises a first electrical resistance when the temperature of the second electrode is below a second switching temperature, wherein said second positive temperature coefficient material comprises a second electrical resistance when the temperature of said second electrode is above said second switching temperature, and wherein said second switching temperature is higher than said first switching temperature.
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Accused Products
Abstract
An electrosurgical surgical instrument can comprise a handle and an end effector, wherein the end effector can comprise first and second jaws which can be opened and closed in order to capture tissue therebetween. In various embodiments, the first and second jaws can comprise one or more electrodes configured to apply a voltage across the tissue, wherein one or both of the first and second jaws can include a plurality of electrodes each comprised of a positive temperature coefficient material having a different switching temperature. The electrical resistances of the electrodes can increase significantly once the temperature of the electrodes exceed their switching temperatures and, owing to the increased electrical resistance, the flow of current through the electrodes can be reduced and/or prevented. In various circumstances, the different switching temperatures of the electrodes can allow some of the electrodes to switch off before the other electrodes.
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Citations
14 Claims
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1. A surgical instrument, comprising:
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a handle; and an end effector, comprising; a first jaw; a second jaw, wherein said first jaw is movable relative to said second jaw between an open position and a closed position; a first electrode comprising a first positive temperature coefficient material interspersed throughout said first electrode, wherein said first positive temperature coefficient material comprises a first electrical resistance when the temperature of said first electrode is below a first switching temperature, and wherein said first positive temperature coefficient material comprises a second electrical resistance when the temperature of said first electrode is above said first switching temperature; and a second electrode comprising a second positive temperature coefficient material interspersed throughout said second electrode, wherein said second positive temperature coefficient material comprises a first electrical resistance when the temperature of the second electrode is below a second switching temperature, wherein said second positive temperature coefficient material comprises a second electrical resistance when the temperature of said second electrode is above said second switching temperature, and wherein said second switching temperature is higher than said first switching temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A surgical instrument, comprising:
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a handle; and an end effector, comprising; a first jaw; a second jaw, wherein said first jaw is movable relative to said second jaw; a first electrode positioned within said first jaw and comprised of a first positive temperature coefficient material, wherein said first positive temperature coefficient material comprises a first electrical resistance when the temperature of said first electrode is below a first switching temperature, and wherein said first positive temperature coefficient material comprises a second electrical resistance at least one order of magnitude higher than said first resistance when the temperature of said first electrode is above said first switching temperature; and a second electrode comprised of a second positive temperature coefficient material, wherein said second positive temperature coefficient material comprises a third electrical resistance when the temperature of the second electrode is below a second switching temperature, wherein said second positive temperature coefficient material comprises a fourth electrical resistance at least one order of magnitude higher than said third electrical resistance when the temperature of said second electrode is above said second switching temperature, and wherein said second switching temperature is higher than said first switching temperature. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification