A pneumatic tool is provided comprising: a motor; a drive mechanism connected to the motor; a cylinder; the drive mechanism comprising a drive bar connected to a piston, the drive bar adapted to drive the piston in a linear direction; the cylinder filled with high pressure gas; wherein the piston is housed in the cylinder and adapted to reciprocate within the cylinder; the piston is connected to a striking member adapted to strike a workpiece; wherein the drive mechanism further comprises a plurality of latching members adapted to be in contact with and lock the drive bar. The latching structure provided by the present invention has a smaller sliding distance and is safer than conventional drive bar latching structures.