Vacuum cleaner filter bag

Claim 1

A VACUUM CLEANER FILTER BAG COMPRISING A BLANK SHEET OF AIR PERMEABLE MATERIAL DEFINING A FRONT WALL, A REAR WALL OF SUBSTANTIALY THE SAME WIDTH AS THE FRONT WALL AND A PAIR OF OPPOSING SIDE WALLS, OPPOSING EDGES OF SAID BLANK BEING SECURED TOGETHER IN AN OVERLAPPING RELATION TO DEFINE A TUBE-LIKE MEMBER, SAID OPPOSING EDGES OF SAID BLANK DEFINING COOPERATING PORTIONS OF SAID REAR WALL, SAID REAR WALL BEING SUBSTANTIAL FLAT AND HAVING A THICKNESS OF SAID BLANK AND HAVING A DOUBLE THICHNESS OF SAID BLANK ONLY WHERE SAID OPPOSING EDGES ARE JOINED IN AN OVERLAPPING RELATION, SAID WALLS BEING JOINED AT ON END OF THE BAG TO DEFINE A PORTION HAVING A NORROW CROSSSECTION SAID FRONT AND REAR WALLS DIVERGING FROM EACH OTHER IN A DIRECTION AWAY FROM SAID ONE END WHEN THE BAG IS EXPANDED TO DEFINE A SUBSTANTIALLY TRIANGULAR CROSS-SECTION AT A LONGITUDINAL PLANE DISPOSED NORMAL TO SAID FRONT AND REAR WALLS, A TOP WALL OF SUBSTANTIALLY THE SAME WIDTH AS SAID REAR WALL CONNECTED TO SAID FRONT, REAR AND SIDE AT THE OTHER END OF THE BAG, FOLD LINES BEING PROVIDED IN SAID REAR AND SIDE WALLS TO PERMIT MOVEMENT OF THE BAG FROM A COLLASPED CONDITION TO AN EXPANDED CONDITION AND SAID TOP WALL EXTENDING FROM A VERTICAL TO HORIZONTAL POSITION, SAID REAR WALL BEING FOLDED BACK UPON ITSELF IN SAID COLLAPSED CONDITION WITH A PORTION OF SAD REAR WALL BEING ADJACENT TO SAID TOP WALL AND FACING IN A COMMON DIRECTION WITH SAID TOP WALL WHICH IS OPPOSITE TO A DIRECTION IN WHICH SAID FRONT WALL FACES, SAID TOP WALL BEING SUBSTANTIALLY NORMALLY TO THE LONGITUDINAL LENGTH DIRECTION OF THE BAG IN SAID EXPANDED CONDITION, AN UPPER FOLD LINE BEING PROVIDED BETWEEN SAID TOP AND FRONT WALLS TO PERMIT ANGULAR MOVEMENT OF SAID TOP WALL RELATIVE TO SAID FRONT WALL WHEN THE BAG MOVES FROM SAID COLLAPSED CONDITION TO SAID EXPANDED CONDITION, AND ACCESS MEANS PROVIDED IN SAID FRONT WALL ADJACENT TO SAID UPPER FOLD LINE AND DIRECTLY IN FRONT OF AN INNER SURFACE PORTION OF SAID TOP WALL WHEN IN SAID COLLAPSED CONDITION FOR PROVIDING ACCESS TO AN INTERIOR OF THE BAG TO PERMIT AIR DIRECTED THROUGH SAID ACCESS MEANS TO IMPINGE ON SAID INNER SURFACE PORTION OF SAID TOP WALL AND URGE UNFOLDING OF SAID REAR WALL AS SAID TOP WALL ANGULARLY MOVES RELATIVE TO SAID FRONT WALL TOGETHER WITH SEPARATION BETWEEN SAID FRONT AND REAR WALLS TO MOVE THE BAG TO SAID EXPANDED CONDITION SUITABLE FOR RECEIVING WASTE MATERIAL.