U.S. patent number 3,738,565 [Application Number 05/062,460] was granted by the patent office on 1973-06-12 for free standing bag.
This patent grant is currently assigned to Mobil Oil Corporation. Invention is credited to Kenneth E. Ackley, William L. Courtney.
United States Patent |
3,738,565 |
Ackley , et al. |
June 12, 1973 |
FREE STANDING BAG
Abstract
To provide a free standing bag of plastic material so that it
will be useful as a grocery bag, a bag is formed folded with a
triangular bottom insert to form a flat bottom having a central
crease, the crease lines being pre-formed in the bag so that it can
be erected and will have side walls completely free of creases; the
side walls of the bags themselves are preferably embossed,
striated, or quilted of double strength material, with embossing or
quilted lines extending, preferably, in two vectorial directions
with respect to the height of the bag so that the bag will have
stiff, self-supporting free standing side walls and can be filled
from the top without requiring any additional holders or
supports.
Inventors: |
Ackley; Kenneth E. (Pittsford,
NY), Courtney; William L. (Palmyra, NY) |
Assignee: |
Mobil Oil Corporation (New
York, NY)
|
Family
ID: |
22042627 |
Appl.
No.: |
05/062,460 |
Filed: |
August 10, 1970 |
Current U.S.
Class: |
383/104; 206/527;
383/109; 383/119 |
Current CPC
Class: |
B65D
31/00 (20130101) |
Current International
Class: |
B65D
30/00 (20060101); B65d 033/10 (); B65d
033/02 () |
Field of
Search: |
;229/55,54R,54L,53,56,57,58,55,60 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Leclair; Joseph R.
Assistant Examiner: Marcus; Stephen
Claims
I claim:
1. Bag of limp plastic material capable to stand free, when
expanded, comprising
a front wall (10) of stiffened plastic material having side edges
(11, 12), a top edge (13) and a bottom edge (14);
a back wall (20) of stiffened plastic material having side edges
(21, 22), a top edge (23) and a bottom edge (24);
a bottom panel (30) of stiffened plastic material joined to said
bottom edges (14, 24) of said front and back panels (10, 20) and
formed with a central crease line (35);
a pair of gussetted side walls (40, 50) of stiffened plastic
material, each said side walls being joined (41, 51; 42, 52) to the
side edge (11, 21; 12, 22) of the front and back walls (10,
20);
said plastic material being embossed along embossing lines having a
vectorial direction longitudinally of said bag, the front, back and
side walls being free from embossing crease lines extending
transversely of the bag;
the junction (34a, 34b) of the side edges of said bottom panel (30)
and the bottom edges (14, 24) of said front and back walls (10, 20)
forming a bottom edge crease line (36a, 36b);
the central crease line (35) of the bottom panel being parallel to
said bottom edge crease lines (36a, 36b) and the bottom panel being
folded inwardly, with respect to the top edge of the side walls of
the bag, to fold the bottom panel within the outline of the front
and back walls (10, 20) when the bag is flat, without introducing a
crease into either of said walls, the bottom panel (30) being
formed integrally with the front and back walls (10, 20) and the
central crease line (35) of the bottom panel (30) being defined by
a plastic heat seam line interconnecting the material forming the
front and back walls (10, 20);
a central point (A) of the respective bottom edge of the side walls
being folded over said bottom panel (30) at the central crease
line;
the side walls (40, 50) each being formed with a longitudinal
central crease line (45, 55) parallel to said side edges (41, 51;
42, 52) and a transverse crease (46, 56), forming an
interconnecting continuation of said bottom edge crease line (36a,
36b) and continuing said crease line around said bag;
the width of said side wall being the same as the width of said
bottom panel;
and a pair of triangular crease line (47, 48, 57, 58) extending at
angles of about 45.degree. from the intersections of the bottom
edge crease lines (36a, 36b) at the junctions of the bottom panel
(30) and said front and back walls (10, 20), respectively, and the
side walls (40, 50), to the longitudinal central crease line (45,
55) of the side walls (40, 50).
2. Bag according to claim 1, wherein the side walls (40, 50) have
top edges and bottom edges;
a central point (A) of the respective bottom edge being joined to
the bottom panel (30) at the central crease line (35) and at a
distance inwardly from the outer edge of the bottom panel (30)
equal to one-half the width of a side wall.
3. Bag according to claim 2, wherein at least a portion of the
material of said side walls (40, 50) forming a triangle and defined
by said transverse crease line (46, 56) and said central point is
adhered to the bottom panel (30).
4. Bag according to claim 1, wherein said plastic material is
polyvinylchloride material.
5. Bag according to claim 1 wherein said plastic material is
polyethelene material.
6. Bag according to claim 1 wherein said plastic material is single
ply approximately one to four mil gauge high density
polyethylene.
7. Bag according to claim 1, wherein said plastic material is
quilted.
8. Bag according to claim 1, wherein said embossing lines form an
interlocked pattern, the pattern being defined by lines extending
other than uninterruptedly transversely of the walls of the
bag.
9. Bag according to claim 1, wherein said plastic material is a
two-layer quilted material having one layer with a substantially
smooth surface and another layer with an embossed surface, the
layer having the substantially smooth surface forming the inside of
said bag, and said layer having the embossed surface is heat-sealed
to the smooth layer along embossing lines and forming the outside
of the bag.
10. Bag according to claim 1 wherein said plastic material is
formed with striations extending longitudinally of the bag.
11. Bag according to claim 1, wherein at least one of said walls
has a longitudinally extending seam line to provide increased
stiffness.
12. Bag according to claim 1, wherein said plastic material is a
two-layer quilted material, having one layer with a substantially
smooth surface and another layer with an embossed surface and
connected at pre-determined quilting lines with said smooth layer,
the embossed portions of said other layer forming, with the smooth
layer, air pockets.
13. Bag according to claim 12, wherein the quilting pattern formed
by said quilting lines is a diamond pattern (FIG. 2).
14. Bag according to claim 12, wherein the quilting pattern formed
by said quilting lines is a staggered brick pattern. (FIG. 6).
15. Bag according to claim 12, wherein the quilting pattern formed
by said quilting lines is a brick walk pattern (FIG. 4).
16. Bag according to claim 15, wherein the brick walk pattern is
angled with respect to the sides at an angle of between 30.degree.
to 60.degree. (FIG. 5).
17. Bag according to claim 16, wherein said angle is about
45.degree. (FIG. 5).
18. Bag according to claim 12, wherein the quilting pattern formed
by said quilting lines is a hexagonal pattern (FIG. 3).
Description
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to free standing bags of plastic
material, and more particularly to bags which can be used as
grocery bags or the like, shipped and stored folded flat and easily
erected to be free standing for packing of groceries, canned goods
and the like therein.
Grocery bags, particularly for use in supermarkets, must stand on
their own bottom, with their vertical sides upright for easy
filling. Paper bags fulfill these requirements; they do, however,
have the disadvantage of generally low strength and, particularly,
low "wet strength" that is, rapidly losing any retention capability
when becoming wet and, upon even localized wetting, readily
disintegrating. Coating paper bags with water-repellent or
water-proof materials, such as plastics, is excessively expensive.
Paper bags have the additional disadvantage that paper sheets must
be secured together, at fold lines with a separately applied
adhesive. Some types of adhesives used, as well as the bags
themselves, attract vermin which is imported in the homes of the
purchasing customer, frequently concealed between folds of the
paper bag.
Bags made of plastic material have the outstanding advantage of
being waterproof, verminproof, resistant to penetration by grease,
oils or the like, and sufficiently flexible to follow contours of
articles packed within the bag to prevent tearing, for example by
corners of square boxes, cans or the like. In spite of these
advantages, however, plastic grocery bags have not found
substantial acceptance due to their inability to remain open, and
erected, for ease of packing without any additional external
support devices.
It is an object of the present invention to provide a plastic
grocery bag or sack which is capable of standing open by itself
during the filling operation.
SUMMARY OF THE INVENTION
Briefly, the plastic grocery bag has side wall and front and back
wall portions, as well as a flat bottom, which are so folded for
storage and shipping that none of the side or front and back walls
have a transverse crease; the side walls have a longitudinal
crease, with a pair of angled crease lines extending, when the bag
is erected, at 45.degree. from the central crease to the base; the
bottom wall, or base has a longitudinal central crease which,
during shipping, may be folded outwardly - for ease of erection,
then preferably, inwardly. Absence of transverse creases permits
the bag to stand erected when opened. The material of the side
walls of the bag is, preferably, stiffened by quilting, embossing
or the like, the quilting or embossing lines having vectorial
dimensions extending both vertically, as well as horizontally, to
provide for stiffening lines tending to keep the bag both open, as
well as the walls erected. Vertical stiffening ribs, in the form of
seam lines or projecting tabs formed during manufacture of the bag
may also be provided.
A particularly suitable material is a double-ply material, in which
the material facing the inside of the bag is smooth, and the
outside embossed and quilted by means of quilting lines to the
inside material, with air pockets formed between the two layers of
materials, the air pockets providing for additional stiffness.
Various quilting or embossing patterns may be used, e.g., diamond,
bee-hive (hexagonal), brick-wall type, "brick walk" type, (that is,
interlaced rectangles arranged with respect to each other in such a
manner that continuous lines extending in any direction are
avoided) or other patterns providing for embossing lines, or for
quilt lines interconnecting the two walls of the bag material in
two vectorial directions. A particularly useful pattern is the
diamond pattern. Some materials can be embossed with vertical
striations.
BRIEF DESCRIPTION OF THE DRAWINGS
Advantages of the invention will become apparent to those skilled
in the art from the following description considered in conjunction
with the drawings wherein;
FIG. 1 is a perspective view, partly broken away, of a bag in
accordance with the present invention just prior to being fully
erected;
FIG. 2 illustrates a diamond pattern for the walls of the bag;
FIG. 3 illustrates a hexagonal pattern;
FIG. 4 illustrates a straight brick walk pattern;
FIG. 5 illustrates a 45.degree. brick walk pattern;
FIG. 6 illustrates a straight brick pattern;
FIG. 7 is a cross-sectional view along line VII--VII of FIG. 6, to
an enlarged scale;
FIG. 8 is a fragmentary perspective view of the bag made of a
unitary tube of material and being unfolded;
FIG. 9 is a further fragmentary view of a bag of FIG. 8 just before
being erected and having an inturned bottom reinforcement pocket
formed by a double fold in the side walls;
FIG. 10 is a fragmentary side elevation of a bag of FIG. 8 which
has been erectedp erected;
FIG. 11 is a sectional view along line XI--XI of FIG. 10 and
illustrating a modification of a bag, partly broken away to show
the construction; and
FIG. 12 is a fragmentary sectional view along line XII--XII of FIG.
11.
DETAILED DESCRIPTION
To permit easy loading of bags, for example in grocery stores,
supermarkets and the like, the bags must be free standing and
self-supporting as generally illustrated in FIG. 1. Paper bags will
readily do this; plastic bags, however, due to the generally limp
nature of the plastic material, present special problems. It has
been found that one of the important features of such a bag is that
the side walls do not have any transverse creases, but rather that
the bag is so shaped that any crease lines, which may be preformed
in the plastic, have at least a substantial vertical component,
that is have a vectorial direction which extends vertically when
the bag stands on a flat bottom. The plastic material, itself, can
be of various types. Polyethylene (PE), and particularly quilted
polyethylene is a preferred material. Polyvinyl chloride (PVC) is
equally useful. PVC sheet material can readily be pre-creased, and
made in such a way that it is substantially stiff.
The bag of FIG. 1 has, generally, a front wall 10 of self shape
retaining plastic material, with side edges 11, 12, a top edge 13
and a bottom edge 14. The back wall 20 is of similar material, and
has side edges 21, 22, a top edge 23 and a bottom edge 24. The
bottom is flat, and is formed of a panel 30 of stiff plastic
material to join the bottom edges 14, 24 of the front and back
panels 10, 20, respectively. The bottom panel need not be unitary,
but may, for example, form a continuation of the side panels and be
seamed in the middle as seen, for example, in FIG. 1;
alternatively, it may comprise a separate panel seamed to the side
panels 10, 20, at the bottom edges 14, 24.
The front and back walls 10, 20 are interconnected by a pair of
side walls 40, 50, which are preferably gusseted, that is have a
longitudinal central crease 45, 55, respectively. The crease lines
are pre-formed and so arranged that, upon opening the bag from a
flat position, the respective panels will fold along the crease
lines to form the erected bag.
The gusseted form of side walls 40, 50, provides additional
stiffness and further results in a roomy, easily packed bag. It
does, however, cause problems in shipping the bag folded flat, to
take up as little space as possible not only for shipment, but also
for storage and to be easy to handle. The bags must, in addition to
being self-supporting, be so arranged that a store clerk can take
one at the free edge and with a minimum of handling open the bag to
its fully extended position, preferably with a single shake which
may catch air in the opening bag.
The side walls 40, 50 which may be separate elements heat-seamed to
the front and back walls, or integral therewith, are joined to the
front and back walls at the edges 11, 21 and 20, 22, respectively.
The bottom panel 30 will have side edges 34a, 34b which are
integrally, or by means of a seam joined to the bottom edges 14, 24
of the front and rear panels, respectively. The edges form a crease
line 36a, 36b which is inwardly extending, that is, about which
half of the bottom panel 30 can fold, but which is never completely
straightened out, forming a 90.degree. angle (see FIG. 1)
interconnecting the bottom and side walls, when the bag is
erected.
To enable inward folding of the gusseted side walls 40, 50 an
inwardly extending crease line 46, 56 interconnects the bottom
panel 30 and the respective side wall. If the bottom panel, and the
respective side wall are made of a single unitary sheet of material
then, in order to provide for proper folding, an additional
triangular in-fold will result, as seen at 59 (FIG. 9); a similar
triangular inward fold 49 will be hidden in FIG. 1. Triangularly
extending crease lines 47, 48 and 57, 58 interconnect the junction
of the bottom panel 30 and the side edges of the front and back
walls with the outwardly extending central crease line 45, 55,
respectively, of the side walls 40, 50. Upon grasping one of the
side or front or back walls of the bag, and shaking it to provide a
small opening, air will catch in the air-impervious plastic of the
walls and the bag will fold open by itself. The pre-formation of
the crease lines described, as well as the absence of transverse
crease lines when the bag is erected will permit it to stand freely
on the flat bottom formed by bottom panel 30.
The material of the bag of FIG. 1 is best seen in FIGS. 2-7.
Preferably, the material is quilted, as seen in cross-section in
FIG. 7. For purposes of clarity, the showing of the material as
double-ply has been omitted in all other drawings.
The material of the bag thus, preferably, has an inner wall element
60 joined at quilting lines, which may be thermoplastic seams 61,
to an outer sheet of material 62. The appearance of the bag,
therefore, will be embossed. Between layers 60, 62, an air pocket
63 will be formed. Manufacture of such double-ply quilted material
is known. It has been found, from experiments, that the stiffness
of quilted material, particularly including air pockets, is
substantially greater than that of materials of equivalent
thicknesses which are single-ply. If the material is not quilted,
but single-ply, it is preferably embossed. FIG. 1 shows vertical
striations 5. FIG. 2 shows a diamond pattern, illustrating
embossing (or quilting) lines extending both in horizontal as well
as vertical direction, that is having vectorial components both
horizontally as well as vertically of the bag. The small diamonds
have, in one example, sides which are about 4 - 9 mm long. FIG. 4
is a straight "brick walk" pattern. There are no continuous
horizontal break lines. The brick walk pattern may be angled, for
example between 30.degree. and 60.degree.; FIG. 5 illustrates the
pattern offset at 45.degree.. FIG. 6 illustrates a brick pattern
which may be placed either vertically, as shown, or horizontally or
at angles, depending upon the size of the bag and its final shape,
and on the direction in which maximum stiffness and resistance
against distortion is desired. A good compromise based on
stiffness, ease of opening, and shape retention has been found to
be the pattern of FIG. 2. Many patterns are, of course, possible;
another suitable one is a hexagonal, or bee-hive shaped pattern
with the flats of the hexagons arranged either as in FIG. 3 that is
horizontally, or vertically, as desired.
The brick wall and diamond patterns exhibit excellent directional
stiffness, i.e., they are relatively stiffer in directions
bisecting the angles formed by the embossing, or quilting lines,
than along those lines. The brick walk, and hexagonal (bee hive)
patterns have an approximately even omnidirectional stiffness,
which, however, is less than the maximum directional stiffness of
the diamond or brick wall pattern. Other patterns than those shown
may, of course, be used.
It is not necessary that the outside surface, that is sheet 62 and
the inside surface, that is sheet 60 (FIG. 7) are the same. As
illustrated, the inside sheet 60 will be smooth, whereas the
outside sheet 62 will have an embossed appearance. It is preferred
that the inside be smooth, for ease of packing. The sheets may for
example, have otherwise different characteristics or appearance,
for example, they may be of different thickness. If single-ply
material is used, then high-density polyethylene of approximately 2
to 3 mil gauge is suitable; the embossing lines may form an
interlocked pattern as, for example, illustrated in FIGS. 3, 4 and
5; a partially interlocked pattern (FIG. 6), or extending lines
(FIG. 2) or form vertical striations 5 (FIG. 1).
FIG. 8 illustrates the bag of FIG. 1 in which the bottom wall is
integral with the side walls, and particularly shows the double
fold-in of the side walls, of which side wall 40 is shown. The bag
is made of tubular material having a central seam which will form
the seam line 35. The formation of the gusseted side walls 40, 50,
having a width equal to the bottom panel 30 can readily be
accomplished by providing pre-formed crease lines 47, 48, as well
as additional edge creases, seen at 46, which, with a pair of
additional creases parallel to creases 47, 48, and not visible in
FIG. 8, will form an in-turned pocket, seen between the extension
of the central crease 45 and the tip of the bottom seam 35, as seen
in FIG. 8. The tip of the folded-in triangle, which forms an
inwardly extending pocket, can be secured at an inner point A to
the central line 35 of the bottom panel 30, or can be left free.
The entire bottom triangular fold-in can even be heat-sealed, or
otherwise secured to the bottom wall 30, as seen at 59 in FIG. 9;
or the lower edges of the gussets of the side wall can be seamed to
a seam along central crease line 35 of the bottom panel 30 with or
without an additional seam at crease lines 46, 56 to the adjacent
edge of the bottom panel 30. Point A, lying on the central line 35
of the bottom panel 30 will be inward from the side edges of the
bottom wall by a distance equal to half the width of the side wall,
or of the bottom panel respectively.
The side walls can be stiffened by stiffening folds 70 (FIG. 11,
FIG. 12), which can extend lengthwise of the bag, as well as across
the bottom panel. If the bag is made of tubular material which is
formed from an originally flat sheet, these stiffening folds may,
simultaneously, form the junction seam of the flat sheets, as best
seen in FIGS. 11 and 12.
When the bag is flattened for shipment, then it is preferably
folded to be completely flat, by compressing the bag in the
position of FIG. 8. Upon grasping a side wall, for example side
wall 10, and shaking the bag, it will catch air and expand through
the position of FIG. 8 towards the position of FIG. 9 and FIG. 1.
Very little additional manual handling, if any, is needed to
completely straighten the bag. As will be seen, the side walls of
the erected bag will not have any circumferential, or transverse
crease lines which might induce collapse of the bag when erected.
The stiffening ribs 70, 71 (FIGS. 11 and 12), if provided, as well
as the nature of the material (for example embossed, or two-ply
quilted) will contribute to keep the bag in erect, upright
position. If the bag is made of PVC, pre-formed crease lines are
particularly easy to apply, although most suitable materials, such
as polyethylene, or other similar plastics, can be made with
pre-formed crease lines into which the bag can naturally fold, or
which will be the lines around which the bag will crease for
shipment and subsequently when erected. Approximately 1-4 mil
preferably 2- 3 mil gauge high-density polyethylene is a strong,
and suitable material, particularly when embossed in a suitable
pattern, for example, as illustrated in FIGS. 1 through 6.
* * * * *