Patent ID: 10287834

Abstract:
A logging tool or 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. At least one arm (12) at a first location is pivotably secured to the body (11) to be extensible therefrom and compressible towards the 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) fixed or fixable relative to the body (11). The locking member (18) defines a moveable end (19) remote from the second location and moveable relative to the arm (12) between at least a first position in which force tending to compress the arm (12) towards the body (11) causes the 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 body (11) causes the stop member (22) to resist movement of the locking member (19) thereby preventing compression of the arm (12) towards the body (11). Alternatively, one or more cam and follower arrangement or rack and pinion arrangement can be used.