Abstract: A flap (14) is mounted on a machine frame (10) for movement to and fro between an open position and a closure position. Opposite a first clamping jaw (22) supported on the machine frame (10) there is a second clamping jaw (24) supported on the flap (14) in order in the clamped position thereof to clamp a saw blade (30) between said second jaw (24) and the first clamping jaw (22). A locking member (48) movable to and fro between a disengaged position and an engaged position permits in its disengaged position opening of the flap (14) and in its engaged position secures the flap (14) in the closure position thereof. The locking member (48) is mounted on the flap (14) and adapted to engage behind a support body (56) disposed on the machine frame (10). A grip (42) for moving the locking member (48) is mounted likewise on the flap (14) for movement to and fro between a rest position and an actuating position.