Core break-off mechanism
- Author:
- Myrick, Thomas M.
- Published:
- April 22, 2003.
- Physical Description:
- 1 electronic document
Online Version
- hdl.handle.net , Connect to this object online.
- Restrictions on Access:
- Unclassified, Unlimited, Publicly available.
Free-to-read Unrestricted online access - Summary:
- A mechanism for breaking off and retaining a core sample of a drill drilled into a ground substrate has an outer drill tube and an inner core break-off tube sleeved inside the drill tube. The break-off tube breaks off and retains the core sample by a varying geometric relationship of inner and outer diameters with the drill tube. The inside diameter (ID) of the drill tube is offset by a given amount with respect to its outer diameter (OD). Similarly, the outside diameter (OD) of the break-off tube is offset by the same amount with respect to its inner diameter (ID). When the break-off tube and drill tube are in one rotational alignment, the two offsets cancel each other such that the drill can operate the two tubes together in alignment with the drill axis. When the tubes are rotated 180 degrees to another positional alignment, the two offsets add together causing the core sample in the break-off tube to be displaced from the drill axis and applying shear forces to break off the core sample.
- Other Subject(s):
- Collection:
- NASA Technical Reports Server (NTRS) Collection.
- Note:
- Document ID: 20080006038.
- Terms of Use and Reproduction:
- No Copyright.
View MARC record | catkey: 17028476