| 摘要 |
Inner core barrel head assembly (10) includes an upper latch body (24), a plurality of latching balls (26) which are retained in the latch body (24) and a locking sleeve (28) disposed within the latch body (24). The sleeve (28) has an outer circumferential latching surface (30) of a first outer diameter and an outer circumferential release surface (32) of a second outer diameter smaller than the first outer diameter. The locking sleeve is axially moveable relative to the upper latch body (24) between a latching position and a release position. In the latching position, the latching surface (30) is in radial alignment with the balls (26), forcing the balls (26) radially outwardly into a latch seat (12) provided on a core barrel (20) attached to a lower end of a drill rod (14). This latches the assembly (10) to the core barrel preventing withdrawal. In the release position, release surface (32) is in radial alignment with the balls (26) allowing the balls (26) to move radially inwardly out of engagement with the latch seat (12).
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