Shifting tool for well apparatus

Claim 1

A WIRE LINE-OPERATED SHIFTING TOOL FOR USE IN LONGITUDINALLY SHIFTING A SLEEVE MEMBER IN THE BORE OF A WELL PIPE, COMPRISING, A MANDREL MEMBER CONNECTIBLE TO A WIRE LINE OPERATING STRING, A TUBULAR HOUSING DISPOSED FOR LIMITED RELATIVE LONGITUDINAL MOVEMENT ABOUT THE MANDREL MEMBER, TWO VERTICALLY SPACED DOG MEMBERS MOUNTED IN THE WALL OF THE HOUSING FOR RADIAL MOVEMENT BETWEEN PROJECTED POSITIONS ADAPTED TO ABUTTINGLY ENGAGE THE ENDS OF SAID SLEEVE MEMBER AND RETRACTED POSITIONS PERMITTING PASSAGE OF THE TOOL THROUGH THE BORE OF THE WELL PIPE AND SAID SLEEVE MEMBER, INWARDLY PROJECTING SHOULDERS ON SAID DOG MEMBERS, SHOULDER MEANS CARRIED BY THE MANDREL MEMBER POSITIONED THEREON TO COACT WITH SAID SHOULDERS ON SAID DOG MEMBERS IN RESPONSE TO LONGITUDINAL MOVEMENT OF THE MANDREL MEMBER IN ONE DIRECTION RELATIVE TO THE HOUSING TO PROJECT ONE OF SAID DOG MEMBERS INTO ABUTTING ENGAGEMENT WITH ONE OF THE ENDS OF SAID SLEEVE MEMBER WHILE INTER-ENGAGING WITH SAID SHOULDERS ON THE OTHER OF SAID DOG MEMBERS IN THE RETRACTED POSITION TO THEREBY RELEASABLY SECURE THE HOUSING TO THE MANDREL MEMBER IN RELATIVE POSITIONS TO HOLD SAID DOG MEMBERS IN THEIR RESPECTIVE POSITIONS, THE PROJECTED DOG MEMBER HAVING A PORTION COACTING WITH THE END OF THE SLEEVE MEMBER WITH WHICH IT IS ENGAGED OPERABLE IN RESPONSE TO RELATIVE MOVEMENT OF THE MANDREL MEMBER IN THE OPPOSITE DIRECTION TO RELEASE THE HOUSING FROM THE MANDREL MEMBER SO AS TO REVERSE THE POSITIONS OF THE DOG MEMBERS RELATIVE TO THE ENDS OF THE SLEEVE MEMBER AND SAID SHOULDERS.