Sleeve valve for well pipe strings with blind closure sleeve

Claim 1

A SLEEVE VALVE FOR WELL PIPE STRINGS, COMPRISING, A TUBULAR BODY COAXIALLY CONNECTIBLE IN A WELL PIPE STRING TO FORM A PART THEREOF, RADIAL PORTS THROUGH THE WALL OF THE BODY COMMUNICATING WITH THE BORE THEREOF, ANNULAR GROOVES IN THE BORE WALL OF THE BODY ABOVE AND BELOW SAID PORTS, AND CLOSURE MEANS FOR SAID PORTS, SAID CLOSURE MEANS COMPRISING A TUBULAR SLEEVE SLIDABLY INSERTABLE IN SAID BORE, RADIALLY MOVABLE LATCH ELEMENTS MOUNTED IN THE WALL OF THE SLEEVE AT LONGITUDIANALLY SPACED POINTS TO REGISTER WITH SAID GROOVES, A TUBULAR MANDREL SLIDABLE IN THE BORE OF SAID SLEEVE, A PAIR OF ANNULAR ENLARGEMENTS ON THE MANDREL LONGITUDINALLY SPACED APART TO CORRESPOND TO THE SPACING OF SAID LATCH ELEMENTS, SAID ENLARGMENTS BEING OPERABLE WHEN THE MANDREL IS MOED TO A FIRST POSITION AT WHICH THE ENLARGEMENTS ARE IN REGISTRATION WITH SAID LATCH ELEMENTS TO PROJECT THE LATTER INTO LATCHING ENGAGEMENT WITH SAID GROOVES AND WHEN MOVED TO A SECOND POSITION OUT OF REGISTRATION WITH THE LATCH ELEMENTS TO RELEASE SAID LATCH ELEMENTS FOR RETRACTION FROM SAID GROOVES, COOPERABLE LATCH MEANS ON THE SLEEVE AND MANDREL FOR RELEASABLY LATCHING THE MANDREL TO THE SLEEVE IN SAID FIRST