An electromechanical surgical device includes an end effector (400) configured to perform at least one function, the end effector including an input drive axle (426) projecting therefrom； and a shaft assembly (200). The shaft assembly includes a rotatable drive shaft (214)； a proximal neck housing (232) supported at a distal end of an outer tube (210)； a distal neck housing (236) pivotally connected to the proximal neck housing； a pivot pin (234) interconnecting the proximal neck housing and the distal neck housing； and a gear train (238) supported in the proximal neck housing, on the pivot pin, and in the distal neck housing. The gear train includes a proximal gear (238a)； an intermediate gear (238b)； a distal gear (238c)； and a pair of output gears (239a, 239b), wherein each output gear defines a coupling socket (239a1, 239b1) each configured to selectively receive the drive axle of the end effector.
