Replaceable surgical scissor blades for surgical instruments

A method of replacing first and second blades of an end effector, comprising:

• providing a surgical tool that includes the end effector and further includes:
• a drive housing;
• an elongate shaft extending distally from the drive housing;
• a wrist arranged at a distal end of the shaft and including a distal clevis, an axle mounted to the distal clevis, and first and second actuation pulleys rotatably mounted to the axle and rotatable about a pivot axis extending through the axle, each actuation pulley providing an actuation boss eccentric to the pivot axis;
• a first blade with a first locking portion and a first terminal end defining a first gap between the first blade and the first terminal end, wherein the first blade is pivotably coupled to the actuation boss of the first actuation pulley;
• and
• a second blade with a second locking portion and a second terminal end defining a second gap between the second blade and the second terminal end, wherein the first blade is pivotably coupled to the actuation boss of the first actuation pulley, and the second blade is rotatably coupled to the first blade at a center pin and pivotably coupled to the actuation boss of the second actuation pulley;
• moving the first and second blades to an over-centered position by rotating the first and second actuation pulleys such that the actuation boss of each actuation pulley is located distal to a centerline of the axle;
• exposing the actuation boss of each actuation pulley once the first and second blades are moved to the over-centered position;
• and
• removing the first and second blades from the first and second actuation pulleys with the first and second blades in the over-centered position.

An end effector for a surgical tool, comprising:

• a wrist including a distal clevis, an axle mounted to the distal clevis, and first and second actuation pulleys rotatably mounted to the axle and rotatable about a pivot axis extending through the axle, each actuation pulley providing an actuation boss eccentric to the pivot axis;
• a first blade with a first locking portion and a first terminal end defining a first gap between the first blade and the first terminal end, wherein the first blade is pivotably coupled to the actuation boss of the first actuation pulley;
• and
• a second blade with a second locking portion and a second terminal end defining a second gap between the second blade and the second terminal end, wherein the second blade is rotatably coupled to the first blade at a center pin and pivotably coupled to the actuation boss of the second actuation pulley,
• wherein the first and second blades are movable between open and closed positions by rotating the first and second actuation pulleys such that the actuation boss of each actuation pulley remains proximal to a centerline of the axle,
• wherein the first and second blades are movable to an over-centered position by rotating the first and second actuation pulleys such that the actuation boss of each actuation pulley is located distal to the centerline, and
• wherein moving the first and second blades to the over-centered position exposes the actuation boss of each actuation pulley, thereby allowing the first and second blades to be removed.