Earth drilling apparatus
A drilling system has an under reamer device, the blades of which are brought into contact with the wall of the dulled hole to be reamed, so that, by merely lifting the drill stem as required, the hole can be reamed and, while the drill stem is left inserted in the ground, the bit and core can be taken out. This is accomplished by a latching device which is integrally formed on the ground surface side of the under reamer device. This latch can be inserted into a drill stem so that the blades can ream holes of a diameter larger than the outside diameter of the drill stem. A recess for engaging with this latching device is formed in the end part of the underground side of the drill stem. Further parts for defining their relative positions and parts for transmitting rotations are formed in both the drill stem and under reamer device, and a core tube and core collecting bit fitted directly to the end part on the underground side of this under reamer device are provided. (2 claims)
- Assignee:
- Sumitomo Metal Mining Co.
- Patent Number(s):
- US 3756331
- OSTI ID:
- 6663863
- Country of Publication:
- United States
- Language:
- English
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