Importance

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Abstract

In a locking mandrel for releasably locking a well tool in a well flow conductor of the type disclosed in U.S. Pat. No. 3,208,531 which includes a tubular body mandrel adapted for securing with a running tool and with a well tool, a locking dog retainer sleeve on the body mandrel, expandible and contractible locking dogs carried by the retainer sleeve, and a locking sleeve movable on the body mandrel within the retainer sleeve between a first position at which the locking dogs are expanded and release positions at which the locking dogs are movable inwardly to release positions, the improvement for releasably latching the locking sleeve at the first locking position on the body mandrel which includes an annular latching boss on the body mandrel and an annular latching flange and recess within the locking sleeve. When the locking sleeve is moved to the first locking position the latching flange passes over the latching boss which is received in the latching recess of the locking sleeve releasably latching the locking sleeve at the first position on the body mandrel. The locking sleeve is unlatched by movement to one of the release positions at which the latching boss moves out of the latching recess. The improved latching structure prevents accidental unlocking of the locking mandrel at low flow rates through the tool.

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First Claim