Patent ID: 8591153

Claim:
A pneumatic drilling device for drilling by allowing a drill to feed while rotating, comprising: a cylindrical body; a ram provided inside the body so that the ram can move forward and backward therein; a spindle air motor provided inside the ram for rotating the drill; a feed air cylinder mechanism for moving the ram forward and backward; and an air supply port for supplying compressed air to the feed air cylinder mechanism and the spindle air motor through an airflow path, the airflow path having: a first flow path for supplying compressed air for driving the spindle air motor; a second flow path communicating with the feed air cylinder mechanism for supplying compressed air for moving the ram forward and backward, the first flow path and the second flow path being separately and independently provided in parallel, wherein: the second flow path includes a forward movement flow path for moving the ram forward, and the forward movement flow path is provided with a pressure adjuster for adjusting forward movement thrust force, and the first flow path includes a motor flow path for driving the spindle air motor, and a second forward-movement flow path branched from the motor flow path for moving the ram forward; an exhaust flow path formed on an outer circumferential portion of the ram for discharging the compressed air supplied to the spindle air motor; and an extension member extending at a rear of the ram and having an exhaust port, wherein the exhaust flow path communicates with the exhaust port to discharge the compressed air out of the exhaust port.