摘要 |
A rotary shaft seal for the rotary cutter of a each boring drill bit includes a fixed seal ring fitted securely in the cutter and having an end face which includes a first tapered surface, a floating seal ring having an end face, which includes a second tapered surface opposing the first tapered surface, and a curved inner circumferential surface, and a resilient O-ring compressed between the curved inner circumferential surface of the floating ring and a bearing portion on which the cutter is rotatably journalled.
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