发明名称 |
SYSTEM FOR OVERBURDEN DRILLING |
摘要 |
The present invention provides a global drilling system comprising a crown bit, a driver drill bit and a square drill bit. The crown bit has a tubular body with an inner surface and an outer surface, wherein the inner surface circumscribes a hollow passageway, and a pair of projections extending into said hollow passageway. The pair of projections are positioned substantially opposite one another on said inner surface. The driver drill bit has a drilling head with a pair of cut-away portions positioned substantially opposite one another and a pair of locking surfaces adapted for engaging the projections on the crown bit. The square drill bit has a drilling head with two tapered cut-away portions positioned substantially opposite one another. Each cut-away portion corresponds to one of the pair of projections such that the drilling head is able to pass through the hollow passageway of the crown bit.
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申请公布号 |
CA2432246(A1) |
申请公布日期 |
2004.12.12 |
申请号 |
CA20032432246 |
申请日期 |
2003.06.12 |
申请人 |
CHARLAND, LUC;CHARLAND, ROGER |
发明人 |
CHARLAND, LUC;CHARLAND, ROGER |
分类号 |
E21B7/20;E21B10/40;E21B10/64;(IPC1-7):E21B10/46 |
主分类号 |
E21B7/20 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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