Surgical instrument including a locking assembly

A disposable loading unit configured for releasable engagement with a surgical instrument, comprising:

• a proximal portion of the disposable loading unit configured for releasable engagement with an endoscopic portion of the surgical instrument;
• a body portion of the disposable loading unit defining a first longitudinal axis;
• an articulating tool of the disposable loading unit assembly disposed distally of the body portion being securable to a distal end of the body portion and defining a second longitudinal axis, the articulating tool assembly being movable from a first position in which the second longitudinal axis is substantially aligned with the first longitudinal axis to a second position in which the second longitudinal axis is disposed at an angle to the first longitudinal axis;
• a locking assembly including a link in mechanical cooperation with the body portion, and a pusher, the pusher being in mechanical cooperation with the body portion and the locking assembly including a pivot in mechanical cooperation with the articulating tool assembly, the pusher having an elongated pusher mating surface dimensioned to mate with an elongated pivot mating surface of the pivot, the pusher being distally biased towards the pivot and forced proximally as the articulating tool assembly is moved to the second position;
• wherein each of the elongated pusher and pivot mating surfaces extends laterally across the first longitudinal axis;
• and
• wherein a length of the pusher mating surface is substantially flat, the substantially flat length of the pusher mating surface being substantially perpendicular to the first longitudinal axis, and wherein a length of the pivot mating surface is substantially flat, the substantially flat length of the pivot mating surface being substantially perpendicular to the second longitudinal axis.