| 摘要 |
Device making it possible to use a tube in which there slide percussive borehole hammers or conventional pick hammers in order to bore holes of large diameter by percussion. It comprises an internal tube 9 surmounted by an adaptor 11 for a rotary motor; a rotating joint 3, associated with this device, supplies the percussion system; a lateral distributor is fitted below the rotating joint; this lateral distributor comprises at its base percussive borehole hammers or adapted conventional pick hammers, at irregular and variable intervals, in line or around the peripheries, placed perpendicular to the distributor and parallel to the internal and external tubes. The external tube has its open upper part receiving the internal tube which slides inside with the percussive pick hammers in their guides passing through the base of the lower tube which ends in the shape of a triangular bevel and the straight face of which is open and provided with inclined scrapers 14 fitted in the direction of rotation. <IMAGE>
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