Surgical stapling apparatus with retractable firing systems

A surgical stapling apparatus comprising:

• a handle assembly including handle housing and a movable handle, the movable handle being movable relative to the handle housing;
• an actuation shaft supported at least in part within said handle housing and mounted to move axially within said handle housing from a fully retracted position to a fully fired position in response to manipulation of said movable handle;
• a control rod interfacing with said actuation shaft, said control rod protruding outward from said handle housing and having a distal end configured to be operably attached to a disposable loading unit;
• and
• means for automatically retracting said actuation shaft to said fully retracted position when said actuation shaft has moved to said fully fired position.

A disposable loading unit for use with a surgical stapling apparatus, said disposable loading unit comprising:

• a tool assembly;
• a housing having a distal end coupled to said tool assembly and a proximal end removably attachable to a portion of the surgical stapling apparatus;
• a drive beam assembly movably supported within said housing and removably attachable to a control rod of the surgical stapling apparatus for selectively driving the drive beam assembly in a distal direction through said tool assembly and selectively retracting the drive beam assembly in a proximal direction;
• and
• at least one energy storing member supported within said housing and interacting with said drive beam assembly to store retraction energy as said drive beam is driven in said distal direction and release said stored retraction energy to assist retracting the drive beam assembly when the drive beam assembly is retracted in the proximal direction.