Captive screw fastener

Claim 1

A SCREW FASTENER PERMANENTLY MOUNTED IN AN ASSEMBLED RELATION ON A CLOSURE FOR FASTENING SAID CLOSURE TO A CONTAINER COMPRISING (A) AN ELONGATED SCREW MEMBER HAVING A CENTRALLY LOCATED SHANK PORTION, (B) A THREADED END PORTION ON ONE END OF SAID SCREW MEMBER OF A LARGER DIAMETER THAN SAID SHANK FOR THREADING INTO A CONTAINER, (C) A HEAD PORTION ON THE END OF SAID SHANK OPPOSITE TO SAID THREADED END PORTION AND HAVING A LARGER DIAMETER THAN SAID SHANK, (D) AN INTERMEDIATE PORTION OF SMALLER DIAMETER THAN SAID HEAD PORTION BUT OF LARGER DIAMETER THAN SAID SHANK PORTION POSITIONED BETWEEN SAID HEAD PORTION AND SAID SHANK PORTION TO DEFINE A FIRST ANNULAR SHOULDER BETWEEN SAID HEAD PORTION AND THE INTERMEDIATE PORTION AND A SECOND ANNULAR SHOULD BETWEEN THE INTERMEDIATE END PORTION AND THE SHANK, (E) A SMOOTH BORE RESILIENT SPLIT RING RETAINER MEMBER SNAPPED OVER AND SLIDABLY MOUNTED ON THE SHANK OF THE SCREW MEMBER, (F) SPRING MEANS SURROUNDING SAID SHANK AND BIASED BETWEEN SAID RETAINER MEMBER AND THE FIRST ANNULAR SHOULDER PORTION, (G) A GENERALLY CYLINDRICAL RECEPTACLE MEMBER HAVING AN AXIAL BORE EXTENDING THERETHROUGH WITH MEANS AT ONE END PORTION THEREOF FOR ATTACHMENT TO THE CLOSURE AND THE OPPOSITE EXTENDED END PORTION THEREOF HAVING AT THE INLET OPENING A CYLINDRICAL PORTION OF A DEPTH GREATER THAN THE THICKNESS OF THE SPLIT RING AND OF A DIAMETER GREATER THAN THE OUTER DIAMETER OF THE SPLIT RING IN ITS RADIALLY UNCOMPRESSED CONDITION, (H) AN INWARDLY BEVELED INNER WALL SURFACE PORTION OF THE CYLINDRICAL MEMBER CONVEYING FROM THE CYLINDRICAL PORTION, TO A DIAMETER LESS THAN THE OUTSIDE DIAMETER OF THE SPLIT RING IN ITS UNCOMPRESSED CONDITION AT A CENTER PORTION OF THE RECEPTACLE, (I) AN ANNULAR GROOVE OF A DIAMETER AT LEAST EQUAL TO THE OUTSIDE DIAMETER OF THE SPLIT RING IN ITS RADIALLY UNCOMPRESSED CONDITION AND OF A DEPTH AT LEAST EQUAL TO THE THICKNESS OF THE SPLIT RING, SAID GROOVE TERMINATING THE INWARDLY BEVELED SURFACE PORTION TO DEFINE A THIRD ANNULAR SHOULDER BETWEEN THE INWARDLY BEVELED SURFACE PORTION AND THE ANNULAR GROOVE, (J) A SECOND CYLINDRICAL PORTION OF A DIAMETER LESS THAN THE DIAMETER OF THE SPLIT RING AT ITS RADIALLY UNCOMPRESSED CONDITION IMMEDIATELY ADJACENT TO THE ANNULAR GROOVE TO DEFINE AN ANNULAR SEAT BETWEEN THE ANNULAR GROOVE AND THE SECOND CYLINDRICAL PORTION, AND (K) SAID SPRING MEANS AND THE INTERMEDIATE PORTION OF THE ELONGATED SCREW PORTION FORMING COMBINED DRIVING MEANS HAVING AN AXIAL LENGTH EXCEEDING THE AXIAL LENGTH FROM THE THIRD ANNULAR SHOULDER TO THE INLET OPENING OF THE RECEPTACLE MEMBER, BUT NOT EXCEEDING THE AXIAL LENGTH FROM THE SEAT TO THE INLET OPENING OF THE RECEPTACLE, SO THAT IN ASSEMBLY THE DRIVING MEANS WILL AXIALLY AND POSITIVELY CONTACT THE SPLIT RING MEMBER TO AXIALLY ADVANCE AND RADIALLY INWARDLY COMPRESS THE SPLIT RING MEMBER AS IT MOVES ALONG THE INWARDLY BEVELED WALL SURFACE PORTION UNTIL IT IS ADVANCED TO THE ANNULAR GROOVE OF THE RECEPTACLE WHERE IT RADIALLY EXPANDS INTO THE GROOVE AND IS PERMANENTLY RETAINED BY THE THIRD SHOULDER AND THE SEAT TO PREVENT DISASSEMBLY OF THE SCREW MEMBER FROM THE RECEPTACLE MEMBER WITHOUT RUPTURE OF THE PARTS.