Retrievable packer

Claim 1

IN A WELL TOOL ADAPTED TO BE RUN INTO A WELL BORE ON A RUNNING-IN STRING, AND COMPRISING: A MANDREL CONNECTIBLE TO THE RUNNING-IN STRING FRICTION MEANS ENGAGEABLE WITH THE WELL BORE WALL AND SHIFTABLY MOUNTED ON SAID MANDREL, MEANS FOR RELEASABLY LATCHING SAID FRICTION MEANS TO SAID MANDREL, AND EXPANSIBLE MEANS OPERATIVELY CONNECTED TO SAID FRICTION MEANS AND ACTUATABLE INTO ENGAGEMENT WITH THE WELL BORE WALL UPON RELATIVE LONGITUDINAL MOVEMENT BETWEEN SAID MANDREL AND SAID FRICTION MEANS, CONTROL MEANS OPERATIVELY CONNECTED WITH SAID FRICTION MEANS AND SAID LATCHING MEANS FOR RELEASING SAID LATCHING MEANS UPON ROTATION OF SAID MANDREL RELATIVE TO SAID FRICTION MEANS, SAID LATCHING MEANS INCLUDING A SEGMENTAL DOG ENGAGEABLE WITH SAID MANDREL, SAID MANDREL AND SAID DOG HAVING COENGAGEABLE ELEMENTS FOR PREVENTING LONGITUDINAL MOVEMENT OF SAID MANDREL REALTIVE TO SAID FRICTION MEANS WHEN SAID ELEMENTS ARE ENGAGED, SAID MANDREL HAVING MEANS FOR EFFECTING DISENGAGEMENT OF SAID MANDREL AND DOG ELEMENTS UPON ROTATION OF SAID MANDREL RELATIVE TO SAID DOG, SAID CONTROL MEANS HAVING MEANS FOR HOLDING SAID DOG AGAINST MOVEMENT WITH SAID MANDREL UPON ROTATION OF SAID MANDREL, INCLUDING A MEMBER SWIVELLY CONNECTED TO SAID FRICTION MEANS, AND MEANS FOR EFFECTING A DRIVE CONNECTION BETWEEN SAID FRICTION MEANS AND SAID DOG HOLDING MEANS.