| 摘要 |
<p>BORE HOLE ENLARGING ARRANGEMENT AND METHOD A bore hole enlarging method and arrangement for connection with a rotary pipe string includes inner and outer body sections 20 and 11 which form a body structure 10 to provide a fluid flow path therethrough for communicating with piston 29 and cylinder 17 formed between the body sections for receiving drilling fluid to effect telescopic movement between the body sections. Cutter arms 40 are pivotally mounted on the inner body section 20 and a cooperable support arrangement 60 on the cutter arms 40 and outer body section 11 cooperate to expand or move the cutter arms 40 outwardly of the body structure 10 upon telescopic movement of the body sections in one relative direction and assist in retracting the cutter arms 40 when desired.</p> |
