Articulated surgical instrument with improved jaw closure mechanism

This invention provides an articulated surgical instrument for use in laparoscopic surgical procedures including, in general, a handle, an elongated shaft, and a tip. The shaft is coupled to the handle, and the tip is pivotally coupled to the distal end of the shaft for articulation about an articulation axis. The tip includes two opposed jaws. The jaws are pivotally coupled at a pivot axis for movement between an open position and a closed position, and at least one of the jaws has a camming portion proximal to the pivot axis of the jaws. The instrument further includes a camming driver disposed in the shaft for reciprocating movement between a proximal position and a distal position. The camming driver has a camming portion. The drive camming portion contacts the jaw camming portion at a cam point. Preferably, the jaw camming portion is a hemispherically-shaped projection and the driver camming portion is a ramp. Movement of the camming driver from its proximal position to its distal position causes the jaws to pivot from their open position to their closed positions.