| 摘要 |
A pneumatically operated impact drilling tool for rotary drilling, includes a reciprocating hammer, an anvil positioned under the hammer and a feeder means extending through the hammer. The drilling tool is connected in a string of drilling pipe and high pressure pneumatic fluid flowing through the drilling pipe operates the impact tool. The feeder directs and times the flow of fluid through ports in the hammer to create a first pressure zone to raise the hammer off the anvil, and a second pressure zone above the hammer to drive the hammer down against the anvil to create an impact on the drill bit. Exhaust ports in the hammer exhaust the fluid from the second pressure zone. |
