Patent ID: 9677360
Date: 2017-06-13
CPC Classifications: E21B

Claim:
1. A system for boring holes with a digger derrick comprising: a shaft configured to be coupled to a source of rotary power; a core barrel having a barrel top and a barrel bottom and configured to rotationally couple to said shaft so said shaft provides rotary power to said core barrel and said shaft is free to translate within said core barrel in a direction from said barrel top toward said barrel bottom; a pilot bit coupled to said shaft, so that said pilot bit is free to translate within said core barrel in a direction from said barrel top toward said barrel bottom and said pilot bit is rotated by said shaft without said pilot bit receiving rotation forces through said core barrel; a hollow member disposed between said source of rotary power and said shaft and said hollow member being configured to transmit force between said source of rotary power and said shaft; a combination of said hollow member and said shaft being, configured to retain said shaft within said hollow member at a first position; wherein said hollow member and said shaft being, in combination, configured to retain said shaft within said hollow member at a second position where an increased amount of said shaft is located within said hollow member; wherein said hollow member is a hollow central stem of an auger; and wherein the auger comprises a helical flighting having an upper portion and a lower portion and the hollow central stem is disposed between said upper portion and said lower portion.