Easy to open handle bag and method of making the same

A method of forming a plurality of easy to open handle bags is provided. The method includes providing a flattened tube of thermoplastic material oriented in a generally longitudinal direction. The flattened tube has a first longitudinal side edge, a second longitudinal side edge, and a transverse heat seal. The tube has first, second, and third sections. The second section is disposed between the first and third sections. The first section is joined to the second section along a generally longitudinal first fold line. The second section is joined to the third section along a generally longitudinal second fold line. A generally rectangular hole is cut through the second section. The generally rectangular hole has a top edge and a bottom edge. The generally rectangular hole is contained transversely between the first and second fold lines. The tube is then Z-folded such that the second section is folded over the third section along the second fold line and the first section is folded over the folded second and third sections along the first fold line. As a result the first, second, and third sections overlap one another. A line of weakness is formed adjacent the heat seal. The overlapped first, second, and third sections are cut along a first cut line that intersects the line of weakness, extends therefrom past the bottom edge of the generally rectangular hole, and intersects the first fold line. The overlapped first, second, and third sections are also cut along a second cut line that intersects the line of weakness, extends therefrom past the bottom edge of the generally rectangular hole, and intersects the second fold line.

FIELD OF THE INVENTION 
The present invention relates generally to the field of thermoplastic bags. 
More particularly, it concerns thermoplastic handle bags having a T-shirt 
configuration. 
BACKGROUND OF THE INVENTION 
For many years, thermoplastic bags have been widely used for a number of 
household and industrial purposes. Many bags have a simple rectangular 
structure comprising two layers of thermoplastic film heat sealed at the 
bag bottom, folded sides and an open top. This simple structure has been 
adapted to form a wide variety of sizes and configurations that vary with 
the intended uses of the bags. 
In recent years, bag manufacturers have developed new types of 
thermoplastic bags such as, for example, draw tape bags, handle bags, and 
bags with protruding top edges. These different bag types provide the user 
with different advantages such as being able to easily close, tie and/or 
identify a bag. However, the easy to open, use and close handle bags have 
traditionally required expensive and complicated manufacturing procedures. 
Furthermore, handle bag manufacturers have experienced cost reduction 
pressure from other products and, as a result of their cost reduction 
efforts, new product configurations have been developed. These new handle 
bag configurations have decreased the manufacturing costs of the product 
but have also made the resulting bags more difficult to open and use. 
For example, one existing low cost handle bag configuration is produced by 
starting with a thin thermoplastic film tube that is transversely heat 
sealed to form individual bags. The tube is then double folded. 
Specifically, the edges of tube are longitudinally folded inward so that 
the edges are adjacent to the middle of the bag. The tube is then folded 
again about its middle thereby forming four overlapped bag sections 
comprising eight layers of thermoplastic material. A corner of the bag is 
then removed to form the handles and bag mouth. Such a manufacturing 
process is described and illustrated in U.S. Pat. No. 4,790,467. 
However, the above described manufacturing process makes the resulting 
handle bag difficult and time consuming to open and use. A user must first 
unfold the second middle fold and then the first quarter folds in sequence 
before being able to open the bag. In addition, this method tends to trap 
air between the folded tube sections which further complicates the 
manufacturing process and reduces efficiency 
Consequently, these deficiencies have created a need for an inexpensive and 
efficient method of manufacturing handle bags that are easy to open, use 
and close. 
SUMMARY OF THE INVENTION 
A method of forming a plurality of easy to open handle bags is provided. 
The method includes providing a flattened tube of thermoplastic material 
oriented in a generally longitudinal direction. The tube has first, 
second, and third sections. The second section is disposed between the 
first and third sections. A generally rectangular hole is cut through the 
second section. The tube is then Z-folded such that the first, second, and 
third sections overlap one another. The Z-folded tube has a first side and 
a second side. A first portion of the overlapped first, second, and third 
sections is cut away adjacent the first side of the Z-folded tube. A 
second portion of the overlapped first, second, and third sections is cut 
away adjacent the second side of the Z-folded tube so as to form the 
handle bag.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
Referring now to the drawings, and more particularly to FIG. 1, there is 
shown a collapsed thermoplastic tube 5 traveling in a longitudinal 
direction 8. The collapsed tube 5 includes an opposing top and bottom 
layer of the thermoplastic film. Each opposing layer may comprise one or 
more layers of thermoplastic material. The transverse direction 9 is 
generally perpendicular to the longitudinal direction 8 in which the 
thermoplastic tube 5 moves. The thermoplastic material used can be any 
thermoplastic material well known to one of ordinary skill in the art and 
as more specifically detailed herein below. The tube 5 includes a 
plurality of interconnected bag forming segments 10. Each bag forming 
segment 10 includes a pair of opposing longitudinal side edges 14 and 16. 
Adjacent bag forming segments 10 are separated from each other by 
transverse heat seals 11 and 12. Each bag forming segment 10 comprises a 
first, second and third section 50, 52 and 54, respectively. The second 
section 52 is disposed between the first section 50 and the third section 
54. The first section 50 is joined to the second section 52 along a 
generally longitudinal first fold line 22. The second section 52 is joined 
to the third section 54 along a generally longitudinal second fold line 
24. 
The method of forming a plurality of interconnected handle bags begins by 
forming a pair of transverse heat seals 11 and 12 for each bag forming 
segment 10 at about bag-length distances apart. To form the heat seals 11 
and 12, the tube 5 travels through a sealing station where the transverse 
heat seals 11 and 12 are formed across the tube 5. The opposing 
thermoplastic layers of the tube 5 are thermally fused to each other along 
the heat seals 11 and 12. Alteratively, one broad heat seal may replace 
the heat seals 11 and 12. This broad heat seal may then either be 
perforated or severed, as described below, to produce the same results 
described herein. 
The method proceeds by cutting a generally rectangular hole 32 through the 
second section 52. The generally rectangular hole 32 is contained 
transversely between the first and second fold lines 22 and 24. A top edge 
31 of the generally rectangular hole 32 is contained longitudinally 
between the pair of heat seals 11 and 12. The tube 5 is cut at a first 
cutting station that includes a cutting instrument, such as a rectangular 
hole punch, that severs both layers of the tube 5 to form the generally 
rectangular hole 32. A generally rectangular cut-out corresponding to the 
generally rectangular hole is then removed. 
Referring now to FIGS. 1, 2b and 3, the method continues by Z-folding the 
tube 5 such that the second section 52 is folded over the third section 54 
along the second fold line 24 and the first section 50 is folded over the 
folded second and third sections 52 and 54 along the first fold line 22. 
Thus, the first section 50 is disposed above the second 52 and the third 
section 54, as illustrated in FIG. 2b (each section is shown as a single 
layer for simplicity, each layer actually comprises two layers of 
thermoplastic film). A top view of the resulting tube 5 is illustrated in 
FIG. 2a. 
Each bag forming segment 10 is then weakened between the heat seals 11 and 
12 at a line of weakness 18. The transverse lines of weakness 18 are 
created between the upper heat seal 12 of one bag forming segment 10 and 
the lower heat seal 11 of an adjacent bag forming segment 10 to form 
separable bags and to facilitate removal of portions 40 and 42, as 
described below. The lines of weakness 18 may be in the form of 
perforations, thinned lines, scored lines, etc. Each transverse line of 
weakness 18 is generally aligned such that it falls on the top edge 31 of 
the generally rectangular hole 32. 
Referring now to FIGS. 2a and 3, in one embodiment, a second cutting 
station cuts the overlapped first, second, and third sections 50, 52 and 
54 along a generally arc shaped first cut line 36 that intersects the line 
of weakness 18 and the first fold line 22, extends therefrom past the 
bottom edge 33 of the generally rectangular hole 32, and again intersects 
the first fold line 22. Next, the second cutting station cuts the 
overlapped first, second, and third sections 50, 52 and 54 along a 
generally arc shaped second cut line 34 that intersects the line of 
weakness 18 and the second fold line 24, extends therefrom past the bottom 
edge 33 of the generally rectangular hole 32, and again intersects the 
second fold line 24. Portions 40 and 42 are then removed, as illustrated 
in FIG. 3, to form a plurality of interconnected handle bags 10. Removed 
portions 40 and 42 include six layers of thermoplastic film. The outline 
of the generally rectangular hole 32 is shown in phantom in the bottom 
part of FIG. 3 because the generally rectangular hole 32 is contained in 
section 52 which is obstructed in this view by folded over section 50. 
The shape of the removed portions 40 and 42 may vary depending on how the 
second cutting station cuts the overlapped first, second, and third 
sections 50, 52 and 54 to form first and second cut lines 36 and 34. Thus, 
two possibilities of how the plurality of interconnected handle bags 10 
will appear when laid flat are illustrated in FIGS. 4a and 4b, 
respectively. Other handle shapes are possible as would be apparent to one 
skilled in the art. 
Therefore, the method of the present invention provides a plurality of 
longitudinally folded and interconnected handle bags 10. In one 
embodiment, the bags 10 are then wound onto a roll for packaging. In 
another embodiment, the bags 10 are severed into individual bags, folded 
transversely and stacked for packaging. In yet another embodiment, each 
bag 10 is first folded transversely and then severed from the 
interconnected bags and stacked for packaging. The above methods provide a 
handle bag that is easy to open, use and close thus saving the user time 
and preventing frustration. 
The thermoplastic materials suitable for the present invention include high 
density and low density polyethylenes. Particularly preferred is linear 
low density polyethylene (LLDPE). LLDPE is an ethylenic copolymer formed 
by copolymerizing ethylene with a minor proportion by weight of an alpha 
olefin monomer containing 4 to 10 carbon atoms. The use of LLDPE in 
garbage bags has permitted manufacturers to increase strength, puncture 
resistance, and tear resistance properties. By way of example, and not 
intended to limit the scope of the present invention, typical film 
thicknesses used for bags of the present invention are from about 0.3 mil 
to about 1.5 mil. 
Accordingly, the present invention provides a low cost method of forming 
handle bags that are easy and less time consuming to open, use and close. 
The claimed method also involves less folding than prior methods of 
forming handle bags. Furthermore, the claimed method improves 
manufacturing efficiency because the open area 32 is trapped between the 
first and third sections of the tube 5. Thus, the open area 32 does not 
interfere with downstream processing of the tube 5 because the likelihood 
of an adjoining portion of the open area 32 getting caught in the 
processing equipment is greatly reduced. Accordingly, the speed and 
efficiency of the manufacturing process is increased. Moreover, the 
Z-folded tube 5 allows air to escape during the folding process. This 
facilitates increased manufacturing speed and efficiency. In contrast, 
prior double folded and C-folded methods tended to trap air between the 
tube sections. In addition, the handle bag resulting from the claimed 
method is also easier to open and use because to open the bag, the user 
need only grip the handles and pull them apart. The user need not rotate 
one wrist while opening the bag as is the case with C-folded bags. 
While the present invention has been described with reference to one or 
more particular embodiments, those skilled in the art will recognize that 
many changes may be made thereto without departing from the spirit and 
scope of the present invention. Each of these embodiments and obvious 
variations thereof is contemplated as falling within the spirit and scope 
of the claimed invention, which is set forth in the following claims.