LAPAROSCOPIC BIPOLAR ELECTROSURGICAL INSTRUMENT

摘要

A bipolar electro-surgical instrument (10) can apply a large closure force between its jaws (15, 16) without damaging the small yoke assembly. The instrument comprises a first jaw having a first flange with a first slot, and a second jaw having a second flange with a second slot. The first and the second jaws are located at a distal end of th e instrument. They comprise an electrically conductive material for conducting bipolar electro-surgical current therebetween. A yoke is attached to a pushrod positioned to electrically insulate the first flange from the second flange. The yoke has a first side facing the first.flange, and a second side facing the second flange. The yoke further comprises a first shoulder, and a second shoulder; a first pin locat ed on the first side, and movably engaged with the first slot; a second pin located on the second side, and movably engaged with the second slot. The first slot and second slot are shaped such that an angle subtended by the first and second jaws decreases with distal motion of the pushrod with first and second cul-de-sacs positioned respectively in the first and second slots to relieve shear stresses on the first and second pins, approximately when the first and second shoulders respectively engage the first and second flanges to provide a closure force between the first and second jaws.