Flat-bottom plastic bags

Claim 2

A flat-bottom bag produced from a length of flattened heatsealable tubular material having front and rear walls united along each longitudinal edge by a gusset; a transverse seal extending transversely of said length to provide a bag having a closed bottom and an open mouth; a first fold line extending across the bag front wall spaced from and parallel to said transverse seal and a complementary parallel and spaced fold line extending across the rear wall of said bag, the spacing between said fold lines being identical to the fully extended width of the bag gusset; a first transverse fold line extending across each gusset in substantial alignment with said front and rear wall fold lines; a first pair of inwardly extending fold lines converging from the extremities of said first transverse fold line to provide a first triangular area in each gusset joined along the median line thereof to said transverse seal; a second pair of inwardly extending fold lines converging from the extremities of said first transverse gusset fold line to provide a second triangular area in each gusset complementary to and contiguous to said first triangular area, said second triangular area terminating in a second transverse fold line extending across the gusset in overlying relationship with respect to the adjacent first fold line; inwardly converging fold lines extending from the extremity of said second transverse fold line and providing a third triangular area, the apex of said third triangular area being located on the central fold line of the gusset; the front wall of said bag being provided with a second transverse fold line parallel to and spaced from said first fold line a distance equal to one-half the width of each gusset, said second transverse fold line being in alignment with the opposed apices of said third triangular areas whereby the folded bottom of said bag may lie flat and in contact with said bag front wall.

Claim 3

A flat-bottom plastic bag including front and rear walls united along each pair of longitudinal edges by an inwardly directed gusset and provided with a transverse seal along the bottom edges to provide a closed bottom and an open mouth, each gusset constituting a side wall of said bag; a first fold line extending across the bag front wall, said first fold line being parallel to and spaced from said transverse seal a distance equal to one-half the width of the gusset; a complementary parallel and spaced fold line extending across the rear wall of said bag, the spacing between said fold lines being equal to the fully extended width of the bag gussets and the area between said fold lines constituting the flat bottom of said bag; a first transverse fold line extending across each gusset in substantial alignment with said front and rear wall fold lines; a first pair of inwardly extending fold lines converging from the extremities of said first gusset transverse fold line to provide a first triangular area in each gusset sealed along the median line thereof to the bag bottom transverse seal; a second pair of inwardly extending fold lines converging from the extremities of said first transverse gusset fold line to provide a second triangular area in each gusset complementary to said first triangular area and contiguous therewith, said second triangular area terminating in a second transverse fold line extending across the gusset in overlying relationship with respeCt to the adjacent first fold line; inwardly converging fold lines extending from the extremity of said second transverse fold line and providing a third triangular area in each gusset complementary to said second triangular area and contiguous therewith, the apex of said third triangular area being located on the center fold line of the gusset; the front wall of said bag also being provided with a second transverse fold line parallel to and spaced from said front wall first transverse fold line a distance equal to one-half of the width of the gusset, said second transverse fold line extending across the front half of each gusset and terminating at each extremity at the apex of each third triangular area whereby the folded bottom of said bag may lie flat in partially overlying relationship with respect to the adjacent portion of said bag front wall.

Claim 4

A flat-bottom plastic bag including front and rear walls united along each pair of longitudinal edges by an inwardly directed gusset and provided with a transverse seal along the bottom edges to provide a closed bottom and an open mouth, each gusset constituting a side wall of said bag; a first fold line extending across the bag front wall, said first fold line being parallel to and spaced from said transverse seal a distance equal to one-half the width of the gusset; a complementary parallel and spaced fold line extending across the rear wall of said bag, the spacing between said fold lines being equal to the fully extended width of the bag gussets and the area between said fold lines constituting the flat bottom of said bag; a first transverse fold line extending across each gusset in substantial alignment with said front and rear wall fold lines; a first pair of inwardly extending fold lines converging from the extremities of said first gusset transverse fold line to provide a first triangular area in each gusset sealed along the median line thereof to the bag bottom transverse seal; a second pair of inwardly extending fold lines converging from the extremities of said first transverse gusset fold line to provide a second triangular area in each gusset complementary to said first triangular area and contiguous therewith, said second triangular area terminating in a second transverse fold line extending across the gusset in overlying relationship with respeCt to the adjacent first fold line; inwardly converging fold lines extending from the extremity of said second transverse fold line and providing a third triangular area in each gusset complementary to said second triangular area and contiguous therewith, the apex of said third triangular area being located on the center fold line of the gusset; the front wall of said bag also being provided with a second transverse fold line parallel to and spaced from said front wall first transverse fold line a distance equal to one-half of the width of the gusset, said second transverse fold line extending across the front half of each gusset and terminating at each extremity at the apex of each third triangular area whereby the folded bottom of said bag may lie flat in partially overlying relationship with respect to the adjacent portion of said bag front wall.