| 摘要 |
An improved earth boring apparatus for soft, hard, and heterogenous formations utilizes a pneumatic hammer combined with an earth boring auger. The pneumatic hammer is supported inside a hollow case of the auger and has a small pilot bit and a large rigid bit plate having the same diameter as the auger flighting. All torque to the apparatus is supplied to the auger case which drives the flighting and the pneumatic bit plate without applying any torque to the pneumatic hammer case. This arrangement utilizes the pneumatic hammer to break up hard material and the auger to remove the cuttings or to cut through soft material. The drive arrangement allows for disassembly of the pilot bit and bit plate without removing the pneumatic hammer. |
