Catch mechanism

Claim 1

IN COMBINATION WITH A CONTAINER HAVING A TUBULAR SIDE WALL OF FLEXIBLE SPRINGY PLASTIC MATERIAL AND AN EDGE AT ONE END THEREOF, A CLOSURE PLATE PIVOTED TO ONE SIDE OF SAID SIDE WALL ADJACENT SAID END AND HAVING A PERIPHERAL EDGE, THE IMPROVEMENT WHICH COMPRISES: A LATCH HAVING AN ELONGATE STIFF SHANK WITH THE LENGTH THEREOF EXTENDING IN THE AXIAL DIRECTION OF SAID SIDE WALL, SAID SHANK HAVING A FIXED END PORTION, AN INTERMEDIATE PORTION, AND A FREE END PORTION, ALL OF SAID PORTIONS BEING INTEGRAL WITH ONE ANOTHER, MEANS FIXEDLY ATTACHING THE FIXED END PORTION AGAINST THE EXTERIOR OF SAID SIDE WALL AT A LOCATION AXIALLY SPACED FROM SAID EDGE AND ON THE OUTER SIDE OF THE SIDE WALL OPPOSITE THAT TO WHICH THE CLOSURE PLATE IS PIVOTED, SAID INTERMEDIATE PORTION AND THE FREE END PORTIONS BEING FREE OF SAID SIDE WALL, AND A FINGER PIECE ON ONE OF SAID INTERMEDIATE AND FREE END PORTIONS, SAID FREE END PORTION EXTENDING BEYOND SAID END EDGE AND OVERLAPPING THE PERIPHERAL EDGE OF SAID CLOSURE PLATE IN THE CLOSED POSITION OF THE LATTER, SAID FREE END PORTION HAVING A NOTCH ENGAGING OVER SAID PERIPHERAL EDGE FOR HOLDING THE PLATE CLOSED, WHEREBY WHEN SAID FREE END PORTION IS LIFTED OUTWARDLY FROM SAID PERIPHERAL EDGE, THE SIDE WALL OF SAID CONTAINER FLEXES ADJACENT THE LOCATION OF ATTACHMENT OF THE FIXED END PORTION AND CONSTITUTES A SPRING HINGE FOR SAID LATCH, SAID CONTAINER WALL HAVING A CONVEX HEAD SURROUNDING THE SIDE WALL ADJACENT THE END EDGE, THE PERIPHERAL EDGE OF SAID CLOSURE PLATE COMPRISING AN OUTWARDLY CONVEX, CONCAVO CONVEX LIP, THE CONCAVE SIDE OF SAID LIP ENGAGING OVER SAID HEAD.