Ultrasonic surgical instrument with staged clamping

An apparatus comprising:

• (a) a shaft assembly;
• and
• (b) an end effector located at a distal end of the shaft assembly, wherein the end effector comprises:
• (i) an ultrasonic blade extending distally therealong relative to the shaft assembly, wherein the ultrasonic blade is configured to vibrate at an ultrasonic frequency, and
• (ii) a clamp arm movable toward the ultrasonic blade from an open position to a first stage followed by a second stage toward a closed position, wherein the clamp arm comprises:
• (A) a shank member pivotally connected relative to the shaft assembly, and
• (B) a clamp pad pivotally connected relative to the shank member,
• wherein the clamp arm is configured to compress tissue against the ultrasonic blade with only a distal portion of the clamp pad in the first stage,
• wherein the clamp arm is configured to compress tissue against the ultrasonic blade with the distal portion and a proximal portion of the clamp pad in the second stage such that the tissue compression begins at the distal portion and subsequently progresses toward the proximal portion,
• wherein the clamp pad is configured to distally move relative to the ultrasonic blade as the clamp arm transitions from the first stage to the second stage, and
• wherein the clamp pad extends along a first plane that is obliquely oriented relative to an opposing surface of the ultrasonic blade in the first stage, and wherein the clamp pad extends along a second plane that is parallel relative to the opposing surface of the ultrasonic blade in the second stage.

An apparatus comprising:

• (a) a shaft assembly;
• and
• (b) an end effector located at a distal end of the shaft assembly, wherein the end effector comprises:
• (i) an ultrasonic blade, wherein the ultrasonic blade is configured to vibrate at an ultrasonic frequency, and
• (ii) a clamp arm comprising a clamp pad movable toward the ultrasonic blade from an open position to a first stage followed by a second stage toward a closed position,
• wherein the clamp arm is configured to compress tissue against the ultrasonic blade with only a distal portion of the clamp pad in the first stage, wherein the clamp pad extends along a first plane that is obliquely oriented relative to an opposing surface of the ultrasonic blade in the first stage,
• wherein the clamp arm is configured to compress tissue against the ultrasonic blade with the distal portion and a proximal portion of the clamp pad in the second stage, such that the tissue compression begins at the distal portion and subsequently progresses toward the proximal portion, wherein the clamp pad is configured to distally move relative to the ultrasonic blade as the clamp arm transitions from the first stage to the second stage such that the clamp pad extends along a second plane that is parallel relative to the opposing surface of the ultrasonic blade in the second stage.