Non-retrievable bridge plug

Claim 1

IN A PACKER HAVING ELEMENT OPERATIVELY MOUNTED AROUND A MANDREL AND ADAPTED FOR EXPANSION INTO SEALING ENGAGEMENT WITH A WALL OF A WELL BORE FOR PACKING OFF THE WELL BORE IN RESPONSE TO AN UPWARDLY DIRECTED FORCE ON SAID MANDREL IN CONJUNCTION WITH A DOWNWARDLY DIRECTED FORCE ON SAID PACKING ELEMENT, THE COMBINATION WITH SAID PACKER OF: MEANS OPERATIVELY COUPLED TO THE UPPER END OF SAID PACKING ELEMENT FOR IMPARTING A DOWNWARDLY DIRECTED FORCE THERETO INCLUDING A SLEEVE MEMBER MOVABLY MOUNTED AROUND SAID MANDREL, SAID SLEEVE MEMBER HAVING AN ANNULAR INTERNAL RECESS FACING SAID MANDREL AND FORMING A DOWNWARDLY FACING SHOULDER; DETAINING MEANS FOR TEMPORARILY PREVENTING UPWARD TRAVEL OF SAID MANDREL RELATIVE TO SAID SLEEVE MEMBER INCLUDING AN ANNULAR EXPANSIBLE MANDREL-GRIPPING MEMBER DISPOSED WITHIN SAID RECESS BELOW SAID SHOULDER AND RELEASABLY ENGAGED WITH SAID MANDREL, AND AN ANNULAR YIELDABLE RESTRAINING MEMBER CONTRACTED AROUND SAID GRIPPING MEMBER AND EXPANDABLE IN RESPONSE TO AN UPWARDLY DIRECTED FORCE OF A PREDETERMINED MAGNITUDE ON SAID GRIPPING MEMBER FOR RELEASING SAID GRIPPING MEMBER FROM ENGAGEMENT WITH SAID MANDREL; AND CAM MEANS ON SAID MANDREL BELOW AND AGIANST SAID GRIPPING MEMBER FOR EXPANDING SAID GRIPPING AND RESTRAINING MEMBERS OUTWARDLY WHENEVER SUCH AN UPWARDLY DIRECTED FORCE OF PREDETERMINED MAGNITUDE IS APPLIED TO SAID MANDREL IN CONJUNCTION WITH A DOWNWARLDY DIRECTED FORCE ON SAID SLEEVE MEMBER.