| 摘要 |
A downhole oil well tool uses impact, reciprocal drilling and an improved rotating bit or like working member, receiving both fluid pressure and weight from an elongated pipe string with a flow bore in order to drive the tool. A valve within tool housing controls fluid pressure to the working end so that the tool pressures up, then releases pressure through the working member allowing the pipe string to load the bit, creating impact. A clutch rotates the working member during drilling to prevent imprint upon the formation. A bias spring is provided to control and adjust the amount of weight on the bit independent of pipe weight.
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