An air perforator relates to percussive machines for drilling rocks from mountings or by hands in construction and mining industries.It relates particularly to a pneumatic drill comprising a percussion assembly (1), a mechanism (4) for independent rotation of drill stem (5) and a valve cock (6) with channels (9 and 11) in its housing and a hollow valve (7). There are holes (8 and 10) on the valve side surface for injecting compressed air there into via channels in the valve cock (6) housing. Operation mode of the pneumatic drill is changed by turning the valve (7) in required positions determining regulations of compressed air injection to the percussion assembly and to the mechanism for independent rotation of drill stem.According to the invention the specific feature is of the pneumatic drill is characterized in that holes (10) on the valve side surface (7) for injecting compressed air to the mechanism (4) for rotation of the drill stem are embodied so that providing maximum compressed air injection to the mechanism for rotation of drill stem, when the compressed air injection to the percussion assembly (1) is limited thus enhancing convenience in operation and its output.
