Note: Descriptions are shown in the official language in which they were submitted.
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THERMOPLASTIC CAG PACK
This invention relates tn a handled thermoplastic bag pack.
Thermoplastic handled grocery sacks have successfully
competed with kraft paper grocery sacks and, indeed; are
establishing an ever-increasing share of the market. The many
bene~icial attributes of plastic grocery sacks are responsible ~or
this success. ~ecause of the nature of thin flexible thermoplastic
film grocery sacks, the handleability, particularly during the
bagging operation in supermarkets9 leaves something to be desired.
A conventional manner of providing handled thermoplastic
sacks is to arrange them in a lay-flat stack of 50? lOO or more and
bond them together by way of an integral tab which extends upwardly
from the bag mouth opening. This tab, in addition to providing the
site at which the plurality of bags are bonded together, also
constitutes the tear-off site for separation of individual bags from
the bonded tabs. These bonded tabs also provide the site from which
the pack of bags can be suspended from some suitable support means.
For instance, a peg or flat tongue or similar suspension means may
extend through an orifice m the bag tabs. The therm~plastic bags
described in U.S. Patent No. 4, 165,832, Kuklies et al, issued
August 28, 1979, and in U.S. Patent No. 4,560,067 of George J. Reimann,
issued December 24, 1985, are examples of the type of thermDplastic
grocery sacks and packs which form the subjec* of the instar.t invention.
While such bag pack assemblies generally function as
intended during the support and dispensing of bags during a typical
checkout procedure in a supermarket, for the purpose of easing
congestion during checkout, any means which will assist in speeding
up the checkout procedure would be an advance in this art. One
cause for the slowdown in the bagging operation employin~ limp,
thin-gauge, thermoplastic film bags is the tendency of the walls of
the bags and the handles of the bags to cling together. The
supermarket employee is slowed down in the bagging procedure oy a
need to carefully separate the front from the back wall of the bag
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preparatory to opening the bag and positioning it properly on its
bag holder so that the mouth of the bag can be opened to receive
goods. Not only does the nature of the film promote film to film
adherence but the fact that the bag packs have been packed close
together following manufacture and during transportation contributes
to the reluctance of the films to separate. In addition to this,
because the front panel of each bag is connected to its suspension
tab there is no place for the bagger to easily insert his fingers or
hand in order to pull the front wall or panel of the bag away from
the rear panel to facilitate bagging.
The present invention provides a plurality of stacked bags
made from thermoplastic film, each bag comprising front and rear
walls; a bottom; an open mouth portion, handles which are integral
extensions of the walls, the handles being located at opposite ends
oF the mouth portion; a pair of superimposed, single film tab
members extending above the front and rear bag walls and above the
open mouth portion, the front tab being coplanar with said front
wall and either (1) completely unconnected thereto, or (2) weakly
connected thereto, the rear tab being coplanar with the rear wall
and connected thereto through a localized line of film weakening
which is comparatively stronger than (2) above. There should be at
least one suspension means in association with the bag pack to
accommodate physical suspension of the pack. A bonding means in
association with the bags to fasten all of said bag structures
together may also be provided.
In the drawings, Figure l is a perspective view of a stack
of bags of one form of the bag structures of the present invention.
Figure 2 is a line drawing illustrating part of the front
wall at the bag mouth opening and its associated front bag tab.
Figure 3 is a line drawing illust~ating part of the rear bag
wall at the bag mouth opening and its associated rear bag tab.
Figure 4 is a line drawing illustrating an alternative part
of the front wall of the bag mouth opening and its associated front
bag tab.
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The bag packs of the present invention are constructed so as
to be best suspended and dispensed from a bag pack holder and
dispenser situated near the checkout counter of a supermarket. A
representative bag pack holder and dispenser is that described in U.S.
Patent 4,062,170. It is to be understood that other 0quivalent holder
dispensers may be employed with the pack of the present invention.
A structural common denominator of these holder dispensers is the
fact that they are designed to support the entire pack of bags which
may contain as many as lûO to 150 lay flat thermoplastic film bags
of the type described herein. They are also designed so as to hold
open and suspend the double film loop handles of the bag to
accommodate the loading of the bag. The bag pack of the present
invention will be described with the understanding that it can best
be utilized with this type of bag pack holder dispenser but with the
additional feature that individual bags will be held at three points
or the equivalent of three points and, thus, better facilitate
loading.
One form of the bag pack and bag pack structure of the
present invention is shown in Figure 1 of the accompanying drawing
and it generally comprises a pack of handled bags lû. The
individual bags a~e formed from a flattened9 side-gusseted
thermoplastic tube. The thermoplastic tube can be conveniently made
of any thermoplastic film or blends of the same. Typical materials
include the polyolefins, e.g., polyethylene, polypropylene,
copolymers of ethylene and any other alpha olefin, etc. As
indicated, the bags are side-gusseted as shown at 12 so as to
provide a width dimension to the bags. It is to be understood
howeverl that the bags need not be side gusseted but may have some
other form, for example, a bottom gusset arrangement. The side
gusset 12 represents a re-entrance or infolding of part of a
~lattened tube in a manner well known to those skilled in the art.
The bags have a front panel 14 and a similar back panel 15 which is
partially shown in Fig 3. The individual ba~s have handles 16 which
are integral extensions of the front and rear panels of the bag.
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Because the hag structure includes side gussets 12, the handles are
composed of double film thicknesses. The individual bags of the bag
pack shown, have handles which are wider at the top 18 than at the
base 20 thereof. This is an optional but desirable feature which
provides the user with more plastic film in the hand grip region in
order to militate against the uncomfortable ~Iropingl~ tendency when
carrying a heavily loaded bag. A handle of more or less uniform
dimensions is also contemplated.
The bag mouth opening will be generally defined by the top
edge of the individual bag structure after it has been removed from
the bag support tabs 26 and 27. The illustrated bag pack shows
stress relief curves 24 near opposite ends of the bag mouth opening
at the base of the handles. This preferred structure permits the
bag mouth opening to be stressed without causing bag mouth tearing
at regions intermediate these stress relief points.
As indicated, the regions 26 and 27 consist of two single
fi7m tab members in association with each bag and it is from these
tab members that the bag pack is suspended from an orifice shown at
28. This is of course only but one type of suspension means. It is
possible that the tabs could be suspended by other means, for
example, a clamp arrangement securely holding all tabs together,
thus, performing the function o~ being a suspension means and a
bonding means for the individual bags. The bag pack can optionally
be suspended by means of holes 36 of Figure 1. These orifices can
be located anywhere in association with the handles. A handle
extension, as shown, or appendages anywhere inside the handle lines
can have suspension holes therein. A preferred form of bonding is
shown at 30, which represents a more or less cylindrical,
thermally-formed~ bond extending through all of the tab members.
These small areas are melt-bonded throughout the entire thickness of
the stack to form a bag pack. Ultrasonic means can easily effect
this bonding.
Line 32 of Figure 1 and Figure 2 represents a line of
complete severance between front panel 14 of each bag in the pack
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and front tab member 26 of each bag member. In other words the
front panel of each bag is not in any way supported by the tabs 26.
This provides what is known as a "front side free~ bag pack
arrangement. This is to be distinguished from the back panel or
wall 15 of each bag, as partially illustrated in F.igure 3, which is
s connected to rear tab 27 by means of a line of film weakening 33.
The particular line of film weakening shown in Figure 3 is a series
of inline interrupted cuts or severances arcing across the bottom of
the tab in registration with severance line 32. Other forms of
preweakening obviously can be employed, such as, a line of
perforations, a line of thinning of thermoplastic film arcing across
the tab, etc.
Figure 4 illustrates an alternative ~orm of the ~ront tab
member and is designated 26'. This tab is generally the same as 26
of Figure 2 except instead of having line 32, a line of complete
severance between front panel lA and front tab me~ber 26, there is a
severance line which leaves the front tab weakly connected to the
front wall. Thus, lines 34 are lines of severance through the fro~nt
tab and points 35 provide the weak connections keeping the front tab
connected to the front wall 14. This weak connection offers no
serious resistance to freeing the front wall for bag loading access
and functions in an equivalent manner to the "front side free"
arrangement of Figure 2. At the same time it has the advantage of
preventing air from entering the gussetted tube during part
transport while the bags and bag packs are being manufactured. In
this way it prevents machine jamming and bag misalignment.
By providing the "front side free" or "substantially front
side free" structure while the backside is still affixed to the rear
tab9 a considerable ease of handling aspect has been designed into
the bag pack structure. With this innovation, a bag pack of the
illustrated structure can be suspended in a bag pack holder
dispenser such as that described in U.S. Patent No. 4,062,170 of
William G. Orem, dated December 13, 1977, said patent keing assignel
to Mobil Oil Corporation. Wh~n it is desired to
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load a bag, the bagger can, with a wiping motion, pass his hand and
fingers down across the face of tab 26 or 26', at the upper region
of the bag mouth, at severance line 32 or 34 and can, with the same
motion, pull the front panel 14 of the bag away from the back panel
15 away from the bag pack. This act alone s31ves the time
consuming problem of attemptinQ to otherwise separate front panel 14
from rear panel 15 of the bag preparatory to placing the loop
handles 16 over the handle holders of the bag pack holder dispenser
device or otherwise opening the bag mouth. By this means, the
productivity aspect of utilizing limp thermoplastic grocery sacks
has been significantly increased. Bagging can be accomplished more
efficiently and quicker than without this structural feature.
As indicated above, the localized line of film weakening 33
in the rear tab can be of any construction which will permit an
individual bag to be separated preferentially along this line. The
strength of this line of weakening should at least be strong enough
to keep the empty bag attached to its associated tab until the
beginning of the bagging operation, i.e., entry of the first items
into the bag. Thus, it should stay affixed to the rear tab while
the two handles are being placed over the handle support members of
the bag pack holder and dispenser or the bag mouth otherwise kept
opened and after this is accomplished then it should stay attached
throughout at least the beginning of bagging. It is possible that
after the ~irst few items are placed in the bag, the connection at
the line of weakening may disconnect, however, at this point the
first goods in the bag will tend to keep the bag open and faciliate
further loading of the bag. While it is difficult to accurately
define the optimum stren~th of the film weakening at this point, it
must be such as to maintain this third point of extension of the bag
mouth opening at least through the beginning of the bagging
operation. If the line of weakening is too strong, then there is a
danger that when the loaded bag is pulled free, it may tear the back
region of the bag mouth opening. Thus, the film weakening must be
such as to defin~tely be predisposed to separate at this line only.
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The orifices 28 and 36 can be of any suitable design or
shape complementary to some suspension means placed within the
orifices. For example, if the suspension means is a round or
cylindrical peg then obviously the orifice would be circular in
shape to receive the peg. A preferred suspension means is either a
flat tongue-shaped member or a tongue-shaped wire-form member which
is adapted to extend through a slit-like orifice in the tab as shown
at 28. The dimensions of the slit orifice, which extends all the
way through the plurality of stacked bag members, should tightly fit
around the suspension means. Since a pack of bags of 50, 100 or
150, polyethylene film bags is quite heavy, there is a need to
provide some peripheral reinforcement to the support orifice 28 so
that during use it does not become distorted or enlarged. The front
tab member 26 or 26' which is fully severed or partially severed
from front wall 14, functions to provide this additional support
about the periphery of the orifice. In addition, the bonding means
shown in the drawings as fused regions 30, closely spaced from the
orifice, contributes to the stren~thening of orifice 28. These
bonding means can be positioned both above and below the orifice in
the manner descriJ:~ed in U.S. Patent 4,560,067 of George J. Reimann,
issued Dec~r 24, 1985.
The bag packs of the present invention may be prepared by
any process or system which will result in the defined bag pack.
One suitable technique can be described as follows:
A thermoplastic tube, for example, of a polyethylene film,
is flattened and gusseted so that the gussets extend inwardly from
the sides to an extent such as is shown, for example, in Figure 1 at
I2. Thereafter, the gusseted tube is sealed transversely along
spaced lines which ultimately constitute the seals at the ends of
the handles and at the bottom of the bag. By this technique a
series of interconnected "pillowcases" is continuously formed.
Thereafter, a suitable mechanism will cut out one end of the pillow
case to simultaneously form the handles and tab members of the
bags. At the same time a perforating tool will pierce through both
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tabs of the structure at points along lines ~2 and 33. Before the
perforating tool retracts from its perforating position a rotating
cylinder or wheel makes contact with front wall 14 adjacent to the
- point of perforation of the front wall so as to sever front wall 14
from tab 26. This is one manner of forming severance line 32.
~ecause of interfacial slip between front wall 14 and rear wall 15,
rear wall 15 remains attached to tab 27 by means of preweakened line
33. Simultaneously with this operation or immediately following it,
the bag and tab structure is separated from the advancing tube and a
stack of registered bag structures is formed. When the appropriate
number of bags are in the stack, the tabs are bonded together and
simultaneously an orifice such as that shown at 28 is formed. It is
to be understood that tab 26 can be severed from wall l~ by any
other convenient technique.
When it is desired that the front tab be only weakly
connected to the front wall of the bag, this can be accomplished by
incompletely severing the front tab. Leaving small connecting
regions, such as points 35 in Figure 4, can be accomplished by first
carefully piercing only the front side of the plastic tube stock
during the gusset making operation of the bag making process. The
piercing slots will correspond to severances 34 leaving small
connecting points 35. Thereafter, a perforating tool will pierce
through the front and back side of the gussetted tube in line ~ith
front slots 34. In the final bags, these operations will produce a
front tab weakly connected to the front wall and a rear tab
connected to the rear wall with a comparatively stronger connection
by virtue o~ more and stronger connecting points.
It is to be understood that the bags described can vary in
dimension and in materials. There is nothing critical about the
gauge dimension of the film employed in the bag. The bag should be
capable of carrying the normal supermarket bag load which can range
anywnere from a few pounds to about 35 pounds.
