| 摘要 |
A lubricating sub-assembly for a rock drill, comprising a housing with means to couple the housing into a drill string carrying a drill bit at its front end, a cavity disposed within the housing for holding a predetermined amount of a bearing lubricant, means for communicating the interior of the cavity with one or more air circulation passages provided in the bit leading to bearings within the drill bit, and means for dispensing a preset amount of lubricant from the cavity to the communicating means.
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