Sleeve features for ultrasonic blade of a surgical instrument

1. An apparatus comprising:

(a) a shaft assembly defining a longitudinal axis; 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,

(ii) a clamp arm having a clamping surface, wherein the clamp arm is configured to move toward and away from a first side of the ultrasonic blade for clamping tissue against the ultrasonic blade with the clamping surface, and

(iii) a sleeve, wherein the sleeve extends longitudinally along and covers at least a portion of a second side of the ultrasonic blade, wherein the sleeve is configured to prevent tissue from contacting the portion of the second side of the ultrasonic blade covered by the sleeve,

wherein the sleeve is movably coupled to the end effector via a movable coupling having a recess, wherein the recess is configured to guide movement of the sleeve transversely relative to the longitudinal axis in directions toward and away from the ultrasonic blade and the clamping surface of the clamp arm in a plane extending perpendicularly to the clamping surface, wherein the sleeve is fixed longitudinally relative to the ultrasonic blade.

2. The apparatus of claim 1 , wherein the sleeve extends distally from the distal end of the shaft assembly.

3. The apparatus of claim 1 , wherein the movable coupling further includes a longitudinally fixed element, wherein the recess is configured to slidably receive the longitudinally fixed element therein to enable transverse movement of the sleeve relative to the longitudinal axis while restricting longitudinal movement of the sleeve relative to the ultrasonic blade.

4. The apparatus of claim 3 , wherein the movable coupling includes an attachment feature rigidly coupled to the sleeve, wherein the recess is arranged on the attachment feature.

5. The apparatus of claim 3 , wherein the clamp arm is pivotally coupled to the shaft assembly with a pivot pin, wherein the longitudinally fixed element comprises the pivot pin.

6. The apparatus of claim 1 , wherein the clamp arm is configured to pivot relative to the ultrasonic blade between open and closed positions, wherein the end effector further comprises a deflection feature operatively associated with the sleeve, wherein the deflection feature is configured to urge the sleeve transversely toward the ultrasonic blade when the clamp arm is in the open position.

7. The apparatus of claim 6 , wherein the deflection feature is coupled to and projects transversely from the sleeve.

8. The apparatus of claim 1 , wherein the sleeve includes a tapered protrusion arranged opposite of the movable coupling, wherein the shaft assembly is operable to selectively engage the tapered protrusion to drive the sleeve transversely toward and away from the ultrasonic blade.

9. An apparatus comprising:

(a) a body;

(b) a shaft assembly extending distally from the body and defining a longitudinal axis, wherein the shaft assembly comprises a translating member, wherein the translating member is operable to translate longitudinally relative to the body between first and second positions; and

(c) 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,

(ii) a clamp arm coupled with the translating member, wherein the clamp arm is configured to move toward a first side of the ultrasonic blade in response to movement of the translating member from the first position to the second position, and

(iii) a sleeve extending along at least part of the length of a second side of the ultrasonic blade,

wherein the translating member is movably coupled with the clamp arm and the sleeve, wherein the translating member is configured to drive at least a portion of the sleeve transversely toward the ultrasonic blade and simultaneously drive the clamp arm away from the ultrasonic blade when the translating member moves from the second position to the first position.

10. The apparatus of claim 9 , wherein at least one of the sleeve or the translating member includes a sloped surface configured to engage a portion of the other of the sleeve or the translating member to effect transverse movement of the sleeve relative to the longitudinal axis.

11. The apparatus of claim 9 , wherein the sleeve is resiliently biased away from the ultrasonic blade.

12. An apparatus comprising:

(a) a shaft assembly defining a longitudinal axis; and

(b) an end effector located at a distal end of the shaft assembly, wherein the end effector comprises:

(i) an ultrasonic blade configured to vibrate at an ultrasonic frequency,

(ii) a clamp arm, wherein the clamp arm is movable to clamp tissue against a first side of the ultrasonic blade, and

(iii) a sleeve confronting a second side of the ultrasonic blade, wherein the sleeve is configured to translate transversely relative to the longitudinal axis between first and second positions, wherein the ultrasonic blade is positioned within an interior of the sleeve in each of the first and second positions, wherein the sleeve is configured to extend around at least a portion of a distal-most end of the ultrasonic blade in each of the first and second positions.

13. The apparatus of claim 12 , wherein the sleeve is movable between the first and second positions such that an interior surface of the sleeve moves transversely toward and away from the second side of the ultrasonic blade.