Patent ID: 9717556
Date: 2017-08-01
CPC Classifications: A61B

Claim:
1. An endoscopic needle knife configured to perform an electrosurgical procedure at a treatment site within a patient, the endoscopic needle knife comprising: a cutting wire configured to conduct an electrical current to perform the electrosurgical procedure; an elongate tubular member; a cutting wire lumen longitudinally extending through the tubular member and configured to receive the cutting wire; and a collet press fit to a distal end of the tubular member, the collet comprising: wherein the inner surface of the collet body exerts an inward force on the cutting wire when the cutting wire is disposed within the central lumen of the collet to create a frictional force that provides resistance to longitudinal movement of the cutting wire at the distal end, and wherein a cross-sectional area of the central lumen is dimensioned relative to a diameter of the cutting wire such that when the collet is press fit to the distal end and the cutting wire is disposed within the central lumen, the frictional force that is created is within a range having a lower bound force value and an upper bound force value, wherein the lower bound force is greater than a maximum external longitudinal force to cause longitudinal movement of the cutting wire relative to the tubular member during operation of the needle knife, and wherein the upper bound force value is less than a longitudinal force exerted on the cutting wire by a control mechanism of the needle knife that is operatively coupled to the cutting wire, and wherein the collet body is dimensioned relative to the tubular member so that the press fit between the collet and the distal end of the tubular member causes a reduction in the cross-sectional area of the central lumen for creation of the frictional force in the range.