Ultrasonic surgical instrument and method of laterally aligning blade with clamp arm

1 . An ultrasonic surgical instrument, comprising:

(a) an end effector including an ultrasonic blade;

(b) a shaft assembly proximally extending from the end effector and defining a longitudinal axis, wherein the shaft assembly includes:

(i) an articulation section configured to articulate from a straight configuration to an articulated configuration to thereby deflect the end effector relative to the longitudinal axis,

(ii) an acoustic waveguide having a flexible waveguide portion positioned within the articulation section, a distal waveguide portion acoustically connected to the ultrasonic blade, and a proximal waveguide portion positioned proximal to the articulation section,

(iii) an articulation band including a band rack gear secured to a proximal end of the articulation band and configured to drive the articulation of the articulation section between the straight configuration and the articulated configuration, and

(iv) a pin distal to the articulation section and configured to constrain the distal waveguide portion to the end effector; and

(c) a body assembly proximally extending from the shaft assembly, including:

(i) a housing,

(ii) a transducer assembly secured to the acoustic waveguide and configured to translate the acoustic waveguide along the shaft assembly, and

(iii) a compensator operatively connected to the articulation band and the acoustic waveguide, the compensator configured to longitudinally urge the acoustic waveguide along the longitudinal axis to thereby pivot the ultrasonic blade about the pin for alignment relative to another portion of the end effector, wherein the compensator includes:

(A) a blade rack gear secured to the proximal waveguide portion, and

(B) an articulation pinion gear meshed between the band rack gear and the blade rack gear.

2 . The ultrasonic surgical instrument of claim 1 , wherein the compensator is further configured to apply an opposing translation to the articulation band relative to the acoustic waveguide.

3 . The ultrasonic surgical instrument of claim 1 , wherein the articulation pinion gear is housed inside of the housing.

4 . The ultrasonic surgical instrument of claim 1 , wherein the pin including a distal blade pin, the compensator further including a proximal blade pin, a blade bias spring, and a spring plunger, the proximal blade pin secured to the proximal waveguide portion, the blade bias spring configured to apply a force to each of the spring plunger and the proximal blade pin.

5 . The ultrasonic surgical instrument of claim 4 , where the spring plunger is configured to apply pressure on the blade rack gear.

6 . The ultrasonic surgical instrument of claim 1 , wherein the body assembly further includes an articulation driver configured to apply an articulation force to thereby drive articulation.

7 . The ultrasonic surgical instrument of claim 6 , wherein the articulation force is configured to be applied to the blade rack gear.

8 . The ultrasonic surgical instrument of claim 6 , wherein the articulation force is configured to be applied to the articulation pinion gear.

9 . The ultrasonic surgical instrument of claim 6 , wherein the articulation force is configured to be applied to the band rack gear.

10 . The ultrasonic surgical instrument of claim 1 , the end effector further including a clamp arm extending along an arm axis and configured to clamp tissue between the clamp arm and the ultrasonic blade, the blade extending along a blade axis, the compensator configured to align the arm axis and the blade axis so as to be positioned in a common plane.

11 . The ultrasonic surgical instrument of claim 1 , the articulation band including a first articulation band, the shaft assembly further including a second articulation band, the band rack gear being a first band rack gear, the blade rack gear being a first blade rack gear, the articulation pinion being a first articulation pinion, the second articulation band including a second band rack gear secured to a proximal end of the second articulation band, the compensator further including:

(A) a second blade rack gear, wherein each of the first and second blade rack gears is secured to the proximal waveguide portion, and

(B) a second articulation pinion gear meshed between the second band rack gear and the second blade rack gear.

12 . The ultrasonic surgical instrument of claim 11 , wherein the first and second articulation bands are configured to translate independent of one another.

13 . The ultrasonic surgical instrument of claim 1 , the end effector further including a clamp arm configured to clamp tissue between the clamp arm and the ultrasonic blade, the compensator configured to maintain relative positioning between the clamp arm and the ultrasonic blade during articulation from the straight configuration to the articulated configuration.

14 . An ultrasonic surgical instrument, comprising:

(a) an end effector, including:

(i) a clamp arm configured to selectively move from an open position toward a closed position, and

(ii) an ultrasonic blade longitudinally fixed relative to the clamp arm in a predetermined longitudinal position,

(b) a shaft assembly proximally extending from the end effector, wherein the shaft assembly includes:

(i) a proximal shaft portion defining a longitudinal axis,

(ii) a distal shaft portion supporting the end effector and distally extending therefrom,

(iii) an articulation section positioned between the proximal and distal shaft portions, wherein the articulation section is configured to articulate from a straight configuration to an articulated configuration to thereby deflect the end effector relative to the longitudinal axis,

(iv) an acoustic waveguide having a distal waveguide portion, a proximal waveguide portion and a flexible waveguide portion positioned therebetween within the articulation section, wherein the distal waveguide portion is acoustically connected to the ultrasonic blade, and

(v) an articulation band including a band rack gear secured to a proximal end of the articulation band and configured to drive the articulation of the articulation section between the straight configuration and the articulated configuration; and

(c) a body assembly proximally extending from the shaft assembly, including:

(i) a transducer assembly secured to the proximal waveguide portion on the longitudinal axis and configured to generate an ultrasonic energy,

(ii) a compensator configured to maintain a relative positioning between the clamp arm and the ultrasonic blade during articulation of the articulation section from the straight configuration to the articulated configuration, wherein the compensator includes:

(A) a blade rack gear secured to the proximal waveguide portion, and

(B) an articulation pinion gear meshed between the band rack gear and the blade rack gear.

15 . The ultrasonic surgical instrument of claim 14 , the shaft assembly further including a pin distal to the articulation section and configured to constrain the distal waveguide portion to the end effector.

16 . An ultrasonic surgical instrument, comprising:

(a) an end effector including an ultrasonic blade;

(b) a shaft assembly proximally extending from the end effector and defining (b) a longitudinal axis, wherein the shaft assembly includes:

(i) an articulation section configured to articulate from a straight configuration to an articulated configuration to thereby deflect the end effector relative to the longitudinal axis,

(ii) an acoustic waveguide having a flexible waveguide portion positioned within the articulation section, a distal waveguide portion acoustically connected to the ultrasonic blade, and a proximal waveguide portion positioned proximal to the articulation section,

(iii) an articulation band configured to drive the articulation of the articulation section between the straight configuration and the articulated configuration, and

(iv) a distal blade pin distal to the articulation section and configured to constrain the distal waveguide portion to the end effector; and

(c) a body assembly proximally extending from the shaft assembly, including:

(i) a housing,

(ii) a transducer assembly secured to the acoustic waveguide and configured to translate the acoustic waveguide along the shaft assembly,

(iii) a compensator operatively connected to the articulation band and the acoustic waveguide, the compensator configured to longitudinally urge the acoustic waveguide along the longitudinal axis to thereby pivot the ultrasonic blade about the distal blade pin for alignment relative to another portion of the end effector,

(iv) a proximal blade pin, secured to the proximal waveguide portion

(v) a blade bias member, and

(vi) a biased plunger,

wherein the blade bias member is configured to apply a force to each of the biased plunger and the proximal blade pin.

17 . The ultrasonic surgical instrument of claim 16 , wherein blade bias member is a blade bias spring.

18 . The ultrasonic surgical instrument of claim 16 , wherein the biased plunger is a spring plunger.

19 . The ultrasonic surgical instrument of claim 16 , wherein blade bias member is a blade bias spring, and wherein the biased plunger is a spring plunger.

20 . The ultrasonic surgical instrument of claim 16 , where the spring biased plunger is configured to apply pressure on the blade rack gear.