| 摘要 |
The subject of the present invention is a drilling bit or bucket. According to the invention, this drilling bit or bucket comprises an upper element 2 or 21, a lower element 1 or 19, one or more extension pieces 15a-15b or 21 which may be inserted between the upper element or lower element, and pairs of junction half-collars for assembling the various elements together. <IMAGE>
|
