Abstract: A new and improved air motor operated rotary earth drilling tool for use with a source of high pressure, high volume compressed air has a circulation control housing, a motor housing, a reduction gear housing, and a bearing housing connected longitudinally in series. The circulation control housing is connected to high pressure, high volume, compressed air and has an outlet opening into the motor housing, and an exhaust opening for discharge of compressed air for flushing cuttings and debris from a bore hole which is controlled by longitudinal movement of an inlet tube. The motor housing has a motor chamber and a sliding vane rotor with a rotary shaft extending into the reduction gear housing. A planetary reduction gear receives the rotor shaft and has a low speed, high torque output shaft extending into the bearing housing. A passageway conducts compressed air around the planetary reduction gear for cooling.

Abstract: Long utility holes, for gas lines, electrical conduit, communications conduit and the like, may be bored or pierced horizontally through the earth, particularly under obstacles, such as buildings, streets, highways, rivers, lakes, etc. Such holes may be bored by an underground drilling mole (underground percussion drill) supported on a hollow drill rod and supplied with compressed air through the rod to operate an air hammer which strikes an anvil having an external boring face, preferably constructed to apply an asymmetric boring force. The drill rod is operated by a drill rig on the surface or recessed in special pit for horizontal drilling and provides for additional sections of pipe or hollow rod as the boring progresses. The asymmetric boring force causes the boring path to curve and, when straight line drilling is needed, the drill rod is rotated to counteract the asymmetric boring force.

Abstract: An earth boring apparatus has a pneumatically operated earth boring tool, a flexible conduit or drill pipe connected to the tool and to a source of pneumatic fluid. The tool has an earth boring member and a reciprocally movable hammer positioned in the tool to apply a percussive force. A valve assembly in the flexible conduit or drill pipe substantially adjacent to the tool between the tool and the source of pneumatic fluid controls the flow of pneumatic fluid to the tool. The valve assembly has a pneumatic pressure-operated valve which is operable in response to the pressure of pneumatic fluid in the flexible conduit or drill pipe to be opened to permit flow of pneumatic fluid to the tool at a predetermined operating pressure to transmit an initial pulse of pneumatic fluid to initiate operation of the hammer. The valve is kept open at a lower pressure than that required to open it.

Abstract: Long utility holes, for gas lines, electrical conduit, communications conduit and the like, may be bored or pierced horizontally through the earth, particularly under obstacles, such as buildings, streets, highways, rivers, lakes, etc. Such holes may be bored by an underground drilling mole (underground percussion drill) supported on a hollow drill rod and supplied with compressed air through the rod to operate an air hammer which strikes an anvil having an external boring face, preferably constructed to apply an asymmetric boring force. The drill rod is operated by a drill rig on the surface or recessed in special pit for horizontal drilling and provides for addition of sections of pipe or hollow rod as the boring progresses. The asymmetric boring force causes the boring path to curve and, when straight line drilling is needed, the drill rod is rotated to counteract the asymmetric boring force.