Coupling feature for circular surgical stapler end effector

A surgical stapling instrument, comprising:

• (a) an anvil defining a plurality of staple forming pockets;
• (b) a stapling head assembly configured to drive a plurality of staples against the staple forming pockets of the anvil, wherein the stapling head assembly comprises:
• (i) an annular deck member, wherein the annular deck member includes a plurality of staple openings,
• (ii) a staple driver member, wherein the staple driver member is configured to drive the plurality of staples from the staple openings of the deck member against the staple forming pockets of the anvil, and
• (iii) a body member fixedly secured to the annular deck member, wherein the staple driver member is slidably housed within the body member, wherein the body member includes a radially expandable collar having at least one latching feature;
• and
• (c) a shaft assembly, comprising:
• (i) a proximal sheath portion,
• (ii) a distal sheath portion, and
• (iii) at least one protrusion extending radially outwardly from the distal sheath portion, wherein the at least one protrusion includes at least one abutment surface configured to engage the at least one latching feature of the radially expandable collar for coupling the stapling head assembly to the shaft assembly.

A method of manufacturing a surgical stapling instrument including (i) a body member including a collar having at least one latching feature, the body member being configured to slidably house a staple driver member, and (ii) a shaft assembly having a sheath portion and at least one protrusion extending radially outwardly from the sheath portion, the at least one protrusion including at least one abutment surface, the method comprising:

• (a) slidably positioning the sheath portion within the collar;
• (b) advancing a proximal portion of the collar proximally over the at least one protrusion, wherein the act of advancing includes transitioning the collar from a radially unexpanded state to a radially expanded state;
• and
• (c) after the act of advancing, transitioning the collar from the radially expanded state toward the radially unexpanded state to engage the at least one latching feature with the at least one abutment surface for coupling the body member to the shaft assembly.