| 摘要 |
A logging tool or logging tool sub (10) for downhole use comprises an elongate logging tool body (11); one or more moveable reaction members; and a locking member for the reaction members. The arrangement includes at least one arm (12) that at a first location is pivotably secured to the logging tool body (11) so as to be extensible therefrom and compressible towards the logging tool body (11), and at a second location spaced from the first location is pivotably secured to a locking member (18); and a stop member (22) that is fixed or fixable relative to the logging tool body (11). The locking member (18) defines a moveable end (19) that is remote from the second location and is moveable relative to the arm (12) between at least a first position in which force tending to compress the arm (12) towards the logging tool body (11) causes the moveable end (19) to move away from the stop member (22), and a second position in which force tending to compress the arm (12) towards the logging tool body (11) causes the stop member (22) to resist movement of the locking member (19) thereby preventing compression of the arm (12) towards the logging tool body (11). Alternative embodiments of the logging tool or logging tool sub include one or more cam and follower arrangement, or rack and pinion arrangement. |
