Knife lockout mechanisms for surgical instrument

1. A method of assembling a cartridge assembly for use with a surgical instrument, the method comprising:

providing a cartridge assembly including:

a channel including a protrusion thereon;

the cover including a blocking member and including a surface defining a plane; and

a knife;

engaging the cover with the channel such that at least a portion of the blocking member moves away from the plane upon contact with the protrusion; and

wherein the blocking member is configured to limit distal translation of the knife.

2. The method of claim 1 , wherein the blocking member is biased towards a position where the blocking member is substantially parallel with the plane.

3. The method of claim 1 , wherein the blocking member is configured to limit distal translation of the knife after the knife has been translated proximally past a predetermined position.

4. A surgical stapling instrument, comprising:

a frame;

an elongate portion extending distally from the frame and defining a longitudinal axis;

a cartridge assembly disposed in mechanical cooperation with the elongate portion, the cartridge assembly including:

a surface defining a plane;

a blocking member, at least a portion of the blocking member being biased towards a position where the blocking member is substantially parallel with the plane, at least a portion of the blocking member being movable out of alignment from the plane;

a knife configured for translation with respect to the surface; and

wherein the blocking member is configured to limit distal translation of the knife.

5. The surgical stapling instrument of claim 4 , further comprising a staple cartridge disposed in mechanical cooperation with the cartridge assembly, the staple cartridge including a plurality of spaced apart staples therein.

6. The surgical stapling instrument of claim 4 , further comprising a movable handle disposed in mechanical cooperation with the frame, wherein at least a partial actuation of the movable handle translates the knife.

7. The surgical stapling instrument of claim 6 , wherein at least a partial actuation of the movable handle in a first direction translates the knife distally and wherein at least a partial actuation of the movable handle in a second direction translates the knife proximally past the blocking member.

8. The surgical stapling instrument of claim 4 , further comprising a sled configured for translation with respect to the surface.

9. The surgical stapling instrument of claim 4 , wherein the blocking member includes a flexible finger.

10. The surgical stapling instrument of claim 4 , wherein the blocking member is configured to allow the knife to travel proximally therepast when the blocking member is out of alignment with the plane.

11. The surgical stapling instrument of claim 4 , further comprising a firing rod extending at least partially through the elongate portion.

12. The surgical stapling instrument of claim 11 , wherein the knife and the firing rod form a knife/firing rod connection.

13. The surgical stapling instrument of claim 12 , wherein the cartridge assembly is a replaceable cartridge assembly, the knife being removably connectable to the firing rod.

14. A cartridge assembly for use with a surgical stapling instrument, the cartridge assembly comprising:

a cover including a blocking member and including a surface defining a plane, the blocking member being biased towards a position where the blocking member is substantially parallel with the plane, wherein at least a portion of the blocking member is movable out of alignment with the plane;

a knife configured for translation with respect to the cover; and

wherein the blocking member is configured to limit distal translation of the knife.

15. The cartridge assembly of claim 14 , wherein the blocking member is configured to limit distal translation of the knife after the knife has been translated proximally past a predetermined position.

16. The cartridge assembly of claim 14 , further comprising a sled configured for translation with respect to the cover.

17. The cartridge assembly of claim 14 , wherein the blocking member includes a flexible finger.

18. The cartridge assembly of claim 14 , wherein the blocking member is configured to allow the knife to travel proximally therepast.