Wireline core barrel

Claim 1

A core barrel for retrieving a core within a substantially cylindrically shaped, tubular, generally vertically oriented, core drilling string, the interior wall of the drill string being provided with a region of abrupt diameter change wherein the smaller diameter section of the region lies above the larger diameter section of the region, said core barrel including: an elongate, generally cylindrically shaped body having a fluted periphery comprising at least two longitudinal ribs and channels, said elongate body adapted to be disposed within the drill string such that the channels thereof are oriented substantially parallel to the axis of the drill string, whereby when said elongate body is disposed within the drill string and a fluid flows within the drill string, the fluid may flow around the periphery of said elongate body, through the channels thereof; means located on at least one of the ribs of said elongate body, connected to said elongated body, laterally extensible with respect to said elongate body, and adapted for engagement with the interior wall of the drill string when said elongate body is within the drill string; and means for selectively resiliently urging said engagement means laterally outward with respect to said elongate body whereby when said engagement means is selectively urged laterally outward and when said engagement means engages the interior wall below the region of abrupt diameter change, said elongate body is inhibited from upward displacement in the drill string by engagement of the engagement means with the interior wall, said urging means comprising a plunger positioned at one longitudinal end of, and axially displaceable relative to, said elongate body, said plunger comprising a generally cylindrically shaped housing having the axis thereof substantially aligned with the axis of said elongate body, the housing provided with a pinnacle at the longitudinal end thereof away from said elongate body, the housing having an axial borehole extending through the longitudinal end thereof toward said elongate body, the borehole having three regions of different diameters: an uppermost region of greatest diameter, a lowermost region of least diameter, and an intermediate region of intermediate diameter, said plunger further comprising a bolt having a head end thereof disposed in the uppermost region of the borehole and of a width greater than the diameter of the intermediate region of the borehole, having a shaft extending through the borehole and of a width approximately equal to the diameter of the lowermost region of the borehole, and having a shaft end threadably connected to said elongate body, said plunger further comprising a compression spring disposed in the intermediate region of the borehole for acting against the bolt head and the housing such that the housing is biased toward said elongate body.