Bags with pinch-type end closure

Claim 1

A BAG FORMED FROM A TUBE HAVING FIRST AND SECOND OPPOSED WALLS JOINED AT THE SIDES OF THE TUBE, SAID TUBE BEING A MULTI-PLY TUBE HAVING AN INNER PLY AND OUTER PLY, SAID TUBE AT ONE END THEREOF HAVING A STEPPED END FORMATION COMPRISING A FIRST FULL-WIDTH EXTENSION OF THE INNER PLY OF THE FIRST WALL PROJECTING BEYOND THE RESPECTIVE END EDGE OF THE FIRST WALL, A SECOND FULL-WIDTH EXTENSION OF THE INNER PLY OF THE SECOND WALL PROJECTING BEYOND THE RESPECTIVE END EDGE OF THE FIRST EXTENSION, AND A THIRD FULL-WIDTH EXTENSION OF THE OUTER PLY OF THE SECOND WALL PROJECTING BEYONG THE RESPECTIVE END EDGE OF THE SECOND EXTENSION, SAID TUBE AT THE OUTER END THEREOF HAVING A CORRESPONDING BUT REVERSED STEPPED END FORMATION COMPRISING A FOURTH FULL-WIDTH EXTENSION OF THE INNER PLY OF THE SECOND WALL PROJECTING BEYOND THE RESPECTIVE END EDGE OF THE SECOND WALL, A FIFTH FULL-WIDTH EXTENSION OF THE INNER PLY OF THE FIRST WALL PROJECTING BEYOND THE RESPECTIVE END EDGE OF THE FOURTH EXTENSION, AND A SIXTH FULL-WIDTH EXTENSION OF THE OUTER PLY OF THE FIRST WALL PROJECTING BEYOND THE RESPECTIVE END EDGE OF THE FIRTH EXTENSION, SAID FIRST, SECOND AND THIRD EXTENSIONS BEING FOLDED OVER ON A FOLD LINE GENERALLY COINCIDENT WITH THE END EDGE OF THE OUTER PLY OF SAID FIRST WALL AT SAID ONE END OF THE TUBE SO THAT THE FIRST EXTENSION OVERLIES SAID FIRST WALL, THE SECOND EXTENSION OVERLIES THE FIRST EXTENSION AND HAS A PORTION PROJECTING BEYOND IT OVERLYING THE FIRST WALL, AND THE THIRD EXTENSION OVERLIES THE SECOND EXTENSION AND HAS A PORTION PROJECTING BEYOND OVERLYING THE FIRST WALL, SAID FIRST EXTENSION AND SAID PORTIONS OF THE SECOND AND THIRD EXTENSIONS BEING ADHERED TO THE FIRST WALL THEREBY TO FORM AN END CLOSURE.