| 摘要 |
<p>1,102,616. Boring earth &c. PRZEDSIEBIORSTWO HYDROGEOLOGIOZNE W WARSZAWIE. 25, May, 1965 [25, May, 1964]. No. 22111/65. Heading E1F. A drill comprises fixed blades 2, pivoted blades 1 and jetting nozzles 6. The blades1 are shown ,pivoted into their open position in which vertical loads on them are reacted by blocks 4. The blades 1 are opened by the action of the drilling fluid and closed by engagement of the edges 5 with the foot of the casing. The nozzles have interchangeable inserts for adjustment of flow. The body of the drill is cast and the faces of the blades are coated with hard material.</p> |
