Pipe recess locking device

Claim 1

A WELL TOOL ADAPTED FOR PASSAGE THROUGH A TUBING STRING HAVING A LATCH KEEPER CONTAINING PORTION WITH WHICH THE TOOL IS TO CO-OPERATE, SAID TOOL INCLUDING A TUBULAR BODY MEMBER HAVING A DOG LOCATING WINDOW IN THE SAID THEREOF, A DOG SHIFTABLY FITTED WITHIN THE WINDOW AND PROVIDED WITH UPWARDLY AND DOWNWARDLY FACING ABUTMENT SURFACES HAVING LOAD TRANSMITTING AND SLIDE BEARING ENGAGEMENT WITH THE BODY MEMBER FOR DOG MOVEMENT LATERALLY TO AND FROM AN OUTWARDLY PROJECTED POSITION AND RECEPTION WITHIN A TUBING STRING KEEPER UPON RADIAL ALIGNMENT THEREWITH, AN EXPANDER MEMBER SLIDABLY ENCLOSED BY THE TUBULAR MEMBER FOR RELATIVE LONGITUDINAL MOVEMENT OF THE MEMBERS WITHIN A GIVEN RANGE AND ADAPTED FOR RELEASABLE CONNECTION WITH A SUSPENSION LINE FOR RUNNING THE WELL TOOL THROUGH A TUBING STRING, A DOG ENGAGING FORMATION ON THE EXPANDER MEMBER HAVING AN UPWARDLY FACING COMMING SHOULDER ENGAGEABLE WITH AN UNDERSIDE OF THE DOG FOR SUPPORTING THE BODY MEMBER AT ONE LIMIT OF THE SAID GIVEN RANGE OF RELATIVE MOVEMENT AND FOR BIASING THE DOG OUTWARDLY UNDER THE WEIGHT OF THE BODY MEMBER, RETAINER MEANS ON SAID MEMBERS HAVING RELEASABLE LATCHING ENGAGEMENT WITH ONE ANOTHER AT THE OPPO-