| 摘要 |
An excavation apparatus, for mounting on track type excavator, having a mast, a sled slidably mounted on the mast, a sled driving system supported by the mast for downcrowding and upcrowding the sled along the mast, and an extendable kelly section system that prevents slippage of the sled relative to the mast. The extendable kelly section system has a non-rotating outer kelly section attached to the sled, and a non-rotating inner kelly section that is extendable from and retractable into the outer kelly section. A bushing assembly maintains the outer kelly section slidable on the mast. The inner kelly section is automatically powered into and out of the outer kelly section a distance proportional to the distance that the sled is downcrowded or upcrowded along the mast while preventing slippage of the inner kelly section relative to the outer kelly section. A rotary motor, attached to the sled, rotates a telescopic shaft housed within the non-rotating kelly sections, which provides rotary power to an excavation tool. Alternatively, a transmission is secured to the lower end of the inner kelly section and the lower end of the telescopic shaft is connected to the input shaft of the transmission to increase the torque to the excavation tool. The transmission, which does not have an external source of transmission fluid, can be a one speed or two speed and can travel downhole. A boom connector and a mechanism for downcrowding and upcrowding the mast on the boom connector provides additional drilling depth capability. A side-to-side mechanism tilts the mast relative to the plane of the boom.
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