A surgical stapling device comprising: an elongated body portion (18,518) defining a longitudinal axis; a tool assembly pivotally supported at the distal end of the elongated body portion (18,518) about a pivot axis which is substantially perpendicular to the longitudinal axis of the elongated body portion, the tool assembly including an anvil assembly and a cartridge assembly housing a plurality of staples, the anvil assembly being movably mounted in relation to the cartridge assembly between open and closed positions, the tool assembly including a mounting assembly supported at a proximal end thereof, the mounting assembly being pivotally secured to the elongated body portion (18,518) about said pivot axis; a flexible drive assembly (212,536) having a distal end (268,682) configured to translate through the cartridge assembly to eject the staples therefrom; first and second support members (255,606) positioned adjacent the pivot axis, wherein the first support member is positioned on one side of the flexible drive assembly and the second support member is positioned on the other side of the flexible drive assembly, each support member having a distal end (260a,616) fixedly attached to the tool assembly and a proximal end (258a,614) fixedly attached to the elongated body portion, the support members each being positioned adjacent the drive assembly to prevent outward buckling of the drive assembly, characterized in that: the distal ends (260a,616) of the support members (255,606) each comprise a distal retaining portion (260b,620) that is fixedly received and engaged within the mounting assembly; the proximal ends of the support members each comprise a retaining portion (258b,618) configured to be fixedly received and engaged within a respective recess (250a,252a,621,622) in the elongated body portion (18,518); and the surgical stapling device further comprises a locking member having an H-shaped body having a pair of legs and a central web, wherein the H-shaped body is press fit into the recesses (250a,252a,621,622) in the elongated body portion adjacent the proximal retaining portions (258b,618) of the first and second support members to fixedly secure the said retaining portions within the recesses. an elongated body portion (18,518) defining a longitudinal axis; a tool assembly pivotally supported at the distal end of the elongated body portion (18,518) about a pivot axis which is substantially perpendicular to the longitudinal axis of the elongated body portion, the tool assembly including an anvil assembly and a cartridge assembly housing a plurality of staples, the anvil assembly being movably mounted in relation to the cartridge assembly between open and closed positions, the tool assembly including a mounting assembly supported at a proximal end thereof, the mounting assembly being pivotally secured to the elongated body portion (18,518) about said pivot axis; a flexible drive assembly (212,536) having a distal end (268,682) configured to translate through the cartridge assembly to eject the staples therefrom; first and second support members (255,606) positioned adjacent the pivot axis, wherein the first support member is positioned on one side of the flexible drive assembly and the second support member is positioned on the other side of the flexible drive assembly, each support member having a distal end (260a,616) fixedly attached to the tool assembly and a proximal end (258a,614) fixedly attached to the elongated body portion, the support members each being positioned adjacent the drive assembly to prevent outward buckling of the drive assembly, characterized in that: the distal ends (260a,616) of the support members (255,606) each comprise a distal retaining portion (260b,620) that is fixedly received and engaged within the mounting assembly; the proximal ends of the support members each comprise a retaining portion (258b,618) configured to be fixedly received and engaged within a respective recess (250a,252a,621,622) in the elongated body portion (18,518); and the surgical stapling device further comprises a locking member having an H-shaped body having a pair of legs and a central web, wherein the H-shaped body is press fit into the recesses (250a,252a,621,622) in the elongated body portion adjacent the proximal retaining portions (258b,618) of the first and second support members to fixedly secure the said retaining portions within the recesses. the distal ends (260a,616) of the support members (255,606) each comprise a distal retaining portion (260b,620) that is fixedly received and engaged within the mounting assembly; the proximal ends of the support members each comprise a retaining portion (258b,618) configured to be fixedly received and engaged within a respective recess (250a,252a,621,622) in the elongated body portion (18,518); and the surgical stapling device further comprises a locking member having an H-shaped body having a pair of legs and a central web, wherein the H-shaped body is press fit into the recesses (250a,252a,621,622) in the elongated body portion adjacent the proximal retaining portions (258b,618) of the first and second support members to fixedly secure the said retaining portions within the recesses.