| 摘要 |
The apparatus includes a directional boring machine capable of simultaneously rotating and pulling a drill string coupled to the impact tool which includes a tubular housing 13 ending in a front bursting or widening head 47, an input shaft 41, bearings 54,56 supporting the input shaft for rotation within the housing, a striker 24 disposed for reciprocation within the housing to deliver impacts to a front anvil 31, and a drive mechanism for simultaneously pulling the impact tool forward in response to a pulling force on the input shaft and for reciprocating the striker from input shaft rotation to drive the tool forward by the action of cyclic impacts on the front anvil. The apparatus eliminates the need to use a separate pneumatic impact tool. The drive mechanism comprises lateral rollers, on a cross-shaft 62 on the end of the shaft 41, which engage an end cam profile 74 fixed to the striker 24 to move it back and then release it for thrust forwardly by springs 81.
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