| 摘要 |
An apparatus for removing an item from a wellbore, said apparatus comprising a bushing (30) having a hollow generally cylindrical shaped body with a bottom, a top and a bore extending from top to bottom, a mandrel (20) extending into said bore, at least one key (31) on one of the mandrel (20) and the bushing (30), a slot system (50) on the other of said mandrel (20) of said bushing (30), said key (31) projecting into said slot system (50), engagement apparatus (18) connected to said mandrel (20) for engaging said item, and milling apparatus (17) connected to the bottom of the bushing (30), wherein said slot system (50) has a top, a bottom, and a series of interconnected slots through which said at least one key (31) is movable, said series of interconnecting slots including exit means for permitting movement of said at least one key (31) out from said slot system (50) thereby permitting free movement of said bushing (30) relative to said mandrel (20).
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