Staple drive assembly

Abstract

A staple drive assembly includes an actuation sled and at least one staple pusher. The staple drive assembly is adapted to fit within a staple cartridge having a plurality of staples and a corresponding number of retention slots. The at least one staple pusher includes at least one pusher plate for releasably engaging a backspan of a staple. The staple pusher may include a plurality of pusher plates that may be laterally and longitudinally spaced apart. An actuation member has at least one angled camming surface for engaging a complimentary angled surface of the at least one staple pusher. Camming engagement between the actuation member and the at least one staple pusher causes vertical movement of the at least one staple pusher. Lateral and longitudinal offset of the actuation member camming surfaces and the corresponding staple pusher following surfaces improves stability and control of the staple pusher during firing.

1 . (canceled) 
     
     
         2 . A staple cartridge comprising:
 a first staple pusher including at least two pusher plates that are laterally spaced apart from each other and aligned lengthwise with respect to a length of the first staple pusher; and   a second staple pusher defining a central longitudinal axis and including pusher plates that are offset from each other lengthwise with respect to a length of the second staple pusher and laterally spaced apart from the central longitudinal axis, the second staple pusher positioned offset relative to the first staple pusher lengthwise with respect to a length of the staple cartridge, the central longitudinal axis bisecting the second staple pusher.   
     
     
         3 . The staple cartridge according to  claim 2 , further comprising a third staple pusher offset relative to the first and second staple pushers lengthwise with respect to the length of the staple cartridge, the third staple pusher including at least three pusher plates that are offset lengthwise with respect to a length of the third staple pusher and laterally spaced apart from each other. 
     
     
         4 . The staple cartridge according to  claim 2 , wherein a pair of first staple pushers and a pair of second staple pushers are disposed in a mirrored relationship about a longitudinal axis defined by the staple cartridge. 
     
     
         5 . The staple cartridge according to  claim 2 , wherein distal-most portions of the at least two pusher plates of the first staple pusher define a distal-most portion of the first staple pusher. 
     
     
         6 . The staple cartridge according to  claim 2 , wherein the second staple pusher is asymmetric with respect to the central longitudinal axis. 
     
     
         7 . The staple cartridge according to  claim 2 , wherein proximal portions of the at least two pusher plates of the first staple pusher are longitudinally spaced apart from a proximal-most portion of the first staple pusher by the same distance. 
     
     
         8 . The staple cartridge according to  claim 2 , further comprising an actuation sled that is translatable along a longitudinal axis of the staple cartridge to contact the first and second staple pushers as the actuation sled translates along the longitudinal axis of the staple cartridge. 
     
     
         9 . The staple cartridge according to  claim 8 , wherein the actuation sled includes at least one camming member and a base, the at least one camming member including spaced apart first and second cam wedges, each cam wedge including a first drive face oriented at a first drive angle with respect to the base and a second drive face oriented at a second drive angle with respect to the base, the first and second drive angles being different. 
     
     
         10 . The staple cartridge according to  claim 9 , wherein the at least one camming member of the actuation sled is disposed on a first side of a longitudinal axis of the actuation sled such that the first and second cam wedges are disposed on the first side of the longitudinal axis of the actuation sled. 
     
     
         11 . The staple cartridge according to  claim 2 , further comprising a housing defining a plurality of retention slots that define a first outer row, a second outer row, and at least one inner row that is positioned between the first and second outer rows. 
     
     
         12 . The staple cartridge according to  claim 11 , wherein the at least two pusher plates of the first staple pusher are engageable with staples retained in the retention slots of the first and second outer rows. 
     
     
         13 . The staple cartridge according to  claim 11 , wherein one of the pusher plates of the second staple pusher is engageable with a staple retained in one of the retention slots of the at least one inner row. 
     
     
         14 . The staple cartridge according to  claim 13 , wherein the retention slots are arranged in columns, the at least two pusher plates of the first staple pusher being aligned with two different respective rows of retention slots within a given column of retention slots. 
     
     
         15 . A staple cartridge comprising:
 a first staple pusher including at least two pusher plates that are laterally spaced apart, the at least two pusher plates longitudinally spaced apart from a proximal-most portion of the first staple pusher by a same distance; and   a second staple pusher defining a longitudinal axis and positioned offset relative to the first staple pusher lengthwise with respect to a length of the staple cartridge, the second staple pusher including pusher plates that are laterally spaced apart from the longitudinal axis of the second staple pusher, the pusher plates of the second staple pusher longitudinally spaced apart from a proximal-most portion of the staple cartridge by different distances.   
     
     
         16 . The staple cartridge according to  claim 15 , wherein distal end portions of the at least two pusher plates of the first staple pusher are longitudinally spaced apart from the proximal-most portion of staple cartridge by a same distance. 
     
     
         17 . The staple cartridge according to  claim 16 , further comprising a housing defining a first outer row of retention slots, a second outer row of retention slots, and at least one inner row of retention slots, the at least one inner row positioned between the first and second outer rows, the retention slots arranged in columns. 
     
     
         18 . The staple cartridge according to  claim 17 , wherein the at least two pusher plates of the first staple pusher are aligned with two different respective rows of retention slots within a given column of retention slots.