Down-the-hole motor for rotary drill rod and process for drilling using

Abstract

The disclosure includes additional features of the apparatus and technique disclosed in Applicant's U.S. application Ser. No. 575,429. For example, in one embodiment, the motor is adapted to drive a rotary drill rod of the type mentioned in the foregoing Application, but wherein the abutment on the rod opens into the working face of the bit; and the anvil member in the motor has a bit on the distal end thereof which is adapted to insert into the opening of the abutment when said end of the anvil member is engaged with the abutment, and the anvil member is relatively rotatably interconnected with the piston member and has means on the periphery thereof for interengaging with the rod to undergo conjoint rotation therewith. Manipulatively, the additional features include a process wherein an inner bit is inserted in the opening of the abutment, having an anvil on the relatively rear end portion thereof, and the anvil is engaged with the abutment and the inner bit with the rod to rotate in conjunction therewith. The hammer blows are applied to the anvil of the inner bit, to drive the rod, and the fluid is discharged from the motor through the inner bit.