Abstract: A longitudinal and rotary vibration dampener or shock absorber for rotary and percussion drill bits comprises a resilient element to absorb axial compression loads, preferably in a compression mode; a resilient element to absorb axial tension loads, preferably in a compression mode; resilient elements to absorb torque loads in clockwise and counterclockwise directions preferably in a compression mode; radial guide surfaces for long wear between the driver and the driven members and preferably spaced apart axially to resist bending couple loads applied across the two members during operation; and a seal and surface to allow passage of air or other fluid through the unit during operation. All resilient elements, guide members, and seals are readily replaceable in the field. The unit is structurally sound and enclosed and is attachable to the drilling rig drive head and drill pipe or to the drill pipe and bit as the case may be.

Abstract: In one type of pneumatic percussion drilling tool, the pneumatic motor has an anvil-bit which is slidable in the forward end of the motor casing between a normal working position and an abnormal advanced position when the tool is hanging off bottom and the pneumatic fluid is caused to bypass the hammer-piston and blow continuously through the anvil-bit. In order to prevent tapping or chattering of the hammer-piston at such time, as a result of leakage of the pneumatic fluid into the forward working chamber, this chamber is vented by means of one or more passages formed in the surface of the anvil-bit member which are open while the tool is blowing and which are closed in the normal operating position of the anvil-bit member. Since the passages are only in the surface of the anvil-bit member, the structure eliminates the need for special configurations of parts to provide interconnecting recesses and passages as in certain of the prior art.

Abstract: 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.