In various embodiments, a surgical instrument can comprise an end effector including achannel configured to support a staple cartridge and, in addition, an anvil pivotable between openand closed positions relative to the staple cartridge channel. The surgical instrument can furthercomprise a closure tube configured to at least partially surround the anvil and the staple cartridgechannel to hold the anvil in a closed position. The closure tube can extend around the anvil agreater distance than the staple cartridge channel. The surgical instrument can further comprise ashaft and, in addition, an articulation joint pivotably connecting the end effector to the shaft.The articulation joint can further comprise a floating guide member which can guidably supporta knife bar extending into the end effector and, at the same time, move independently of the endeffector and the shaft to provide such support.
