Ultrasonic surgical instrument with removable shaft assembly portion

An apparatus, comprising:

• (a) a body;
• (b) a shaft assembly, wherein the shaft assembly comprises:
• (i) an outer tube defining an elongate opening along an outer surface, wherein the entire outer tube is configured to be removably coupled with the body,
• (ii) a proximal inner tube member, wherein the proximal inner tube member is integral with the body,
• (iii) a distal inner tube member comprising a coupling member, wherein the distal inner tube member is configured to be removably coupled with the proximal inner tube member via the coupling member, wherein the elongate opening houses the coupling member, and
• (iv) an acoustic waveguide, wherein the acoustic waveguide is integral with the body;
• and
• (c) an end effector, wherein the end effector comprises:
• (i) an ultrasonic blade acoustically coupled with the acoustic waveguide, and
• (ii) a clamp arm, wherein a first portion of the clamp arm is pivotably coupled with a distal end of the outer tube, wherein a second portion of the clamp arm is pivotably coupled with a distal end of the distal inner tube member.

A method of assembling a surgical instrument, the method comprising:

• (a) grasping a first sub-assembly, wherein the first sub-assembly comprises:
• (i) an outer tube comprising a first alignment feature,
• (ii) a distal inner tube portion, and
• (iii) a clamp arm, wherein the clamp arm is pivotably coupled with the outer tube, wherein the clamp arm is further pivotably coupled with the distal inner tube portion;
• (b) grasping a second sub-assembly, wherein the second sub-assembly comprises:
• (i) a body comprising a knob, wherein the knob is configured to rotate the rest of the second sub-assembly about a longitudinal axis, wherein the knob comprises a second alignment feature,
• (ii) an acoustic waveguide extending distally from the body,
• (iii) a proximal inner tube portion extending distally from the body, and
• (iv) an ultrasonic blade positioned at a distal end of the acoustic waveguide;
• (c) aligning the first alignment feature of the outer tube with the second alignment feature of the knob;
• and
• (d) moving the first sub-assembly relative to the second sub-assembly, thereby securing the outer tube to the body, and thereby securing the distal inner tube portion to the proximal inner tube portion, wherein moving the first sub-assembly relative to the second sub-assembly further comprises rotating the first alignment feature along the longitudinal axis about a path defined by the second alignment feature.