Articulating surgical stapling apparatus with pivotable knife bar guide assembly

A surgical stapling apparatus, comprising:

• a housing assembly;
• an adapter assembly extending from the housing assembly;
• and
• a reload selectively attachable to the adapter assembly, the reload supporting an end effector on a distal end portion of the reload, the reload including:
• a firing assembly including a flexible knife bar assembly that is selectively advanceable through the end effector for firing the end effector;
• an articulation assembly having an articulation link assembly and a pivotable bar guide assembly, the articulation link assembly coupled to the end effector, the articulation link assembly being actuatable to cause the end effector to move relative to the adapter assembly between an unarticulated position and an articulated position;
• and
• an articulation guide associated with the pivotable bar guide assembly to enable the flexible knife bar assembly to advance through the pivotable bar guide assembly when the end effector is disposed in the unarticulated position or the articulated position.

A reload for a surgical stapling apparatus, the reload comprising:

• a shaft assembly;
• an end effector supporting a flexible knife bar assembly that is selectively advanceable through the end effector for firing the end effector;
• an articulation link assembly coupled to the end effector and actuatable to cause the end effector to articulate relative to the shaft assembly between an unarticulated position and an articulated position;
• a pivotable bar guide assembly configured to bend the flexible knife bar assembly when the end effector articulates relative to the shaft assembly;
• and
• an articulation guide associated with the pivotable bar guide assembly to enable the flexible knife bar assembly to advance through the pivotable bar guide assembly when the end effector is disposed in the unarticulated position or the articulated position.