Transverse direction zipper attaching apparatus and method

A funnel for a form-fill-seal (FFS) machine configured to make transverse-zippered reclosable packages from a continuous supply of thermoplastic film having a plurality of zipper strips transversely sealed thereto at package length intervals is provided. The funnel includes a lower surface a contoured to keep the zipper profiles substantially parallel to each other as the thermoplastic film is fed over the FFS machine forming collar and folded around the FFS machine filling tube. A method and apparatus for making transverse zippered reclosable packages is also provided.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to reclosable plastic bags and packages of 
the type in which food products, such as chips and cereal, and other goods 
may be packaged for sale to consumers. More particularly, the present 
invention relates to improvements in the art of making reclosable plastic 
bags on form-fill-seal (FFS) machines wherein the zipper is applied 
transverse to the running direction of the film from which the bag is 
formed. 
2. Description of the Prior Art 
The present invention relates to improvements in the package-making art and 
may be practiced in the manufacture of thermoplastic bags and packages of 
the kind that may be used for various consumer products, but which are 
particularly useful for food products which must be kept in moisture and 
air-tight packages, free from leakage until initially opened for access to 
the product contents, which packages are then reclosable by zipper means 
to protect any remainder of the product therein. 
The prior art is fairly well-developed, but nevertheless remains 
susceptible to improvement contributing to increased efficiency and cost 
effectiveness. 
In particular, the present invention relates to the area of reclosable 
packaging known as the "transverse zipper". When making a bag with a 
transverse zipper, the zipper is attached transverse to the longitudinal 
axis of the material used to make the bag, as opposed to being attached to 
the bag material parallel to the longitudinal axis. A method and apparatus 
for making reclosable plastic bags with a transverse zipper is disclosed 
in U.S. Pat. No. 4,909,017. 
A typical prior art FFS machine 10 configured for making 
transverse-zippered reclosable plastic bags is shown in FIG. 1. 
Thermoplastic film 12 from which the bags will be formed is paid off from 
a continuous roll thereof 14 in increments equal to the length of the bags 
which will ultimately be formed from the film 12 in the FFS machine 10. 
The longitudinal axis of the film 12 is parallel to the direction of 
travel of the film 12. Each time the film 12 comes to rest, a zipper strip 
16 supplied from a continuous roll 24 is positioned on the film 12 
transverse to the longitudinal axis by a positioning device 18, with one 
profile 20 of the zipper strip 16 on top of the other profile 22 of the 
zipper strip 16. The positioning device 18 can take any of a variety of 
forms well-known to those skilled in the reclosable packaging art, such as 
a vacuum conveyor for pulling the zipper strip 16 across the film 12 and a 
knife for cutting the zipper strip 16 from the continuous roll thereof 24. 
The zipper strip 16 is then initially sealed or tacked to the thermoplastic 
film 12 by an attaching device 26, such as a pair of heater bars. FIG. 2 
shows a cross section of the zipper strip 16 and the film 12 just after 
the zipper strip 16 has been attached thereto by the attaching device 26. 
Each profile has a leading flange 28, 29 projecting in the direction of 
motion of the film 12 and a trailing flange 30, 31 projecting in a 
direction opposite to its leading flange. The orientation of the profiles 
depends on which side of the zipper, if any, is particularly adapted to be 
the opening side. As disclosed in U.S. Pat. No. 4,909,017, the zipper 
strip 16 has a length approximately equal to half the width of the film 12 
and is disposed centrally thereon. The profile flanges are substantially 
parallel to each other. 
After the zipper strip 16 is positioned on the thermoplastic film 12, the 
attaching device 26 attaches the leading flange 29 of the lower profile 22 
to the thermoplastic film 12. A series of zipper strips 16 are thusly 
initially attached to the thermoplastic film 12 at bag length increments 
as the thermoplastic film 12 is paid off the continuous roll thereof 14, 
as shown in FIG. 1. The transverse zipper-equipped film is then fed into 
the FFS machine 10, where the bags are formed and the final zipper seals 
are made. 
At the FFS machine 10, the thermoplastic film 12 is fed downwardly over a 
forming collar 34 and folded around a filling tube 36. The edges of the 
film are brought together and pressed together by a pair of rollers 38. 
The edges are then sealed together by heater bars 40 to form a 
longitudinal back seal 42. Contents may then be dropped through the tube 
36 into a bag 44 which has a lower seal 46. As discussed below, the lower 
seal 46 was made when the preceding bag was completed. 
After introduction of the contents, the top of the bag is completed by the 
action of cross seal jaws 48, which perform five substantially 
simultaneous functions. First, the cross seal jaws 48 finally seal the 
leading flanges 28, 29 of the profiles to front and back bag walls without 
sealing the leading flanges 28, 29 to each other. Second, the cross seal 
jaws 48 seal the trailing flanges 30, 31 of the zipper strip to the front 
and back bag walls without sealing the trailing flanges 30, 31 to each 
other. The use of a heat activated adhesive on the flanges facilitates 
sealing of the flanges to the bag walls without sealing the flanges to 
each other. Third, the cross seal jaws 48 seal the top of the bag to form 
a pilfer evident seal 50. Fourth, the cross seal jaws 48 make the lower 
seal 46 for the succeeding bag. And fifth, the cross seal jaws 48 cut the 
completed bag 44 from the film 12. 
Manufacture of transverse-zippered reclosable bags in accordance with the 
foregoing, however, has proven problematic. Specifically, because the 
leading flange 28 of the upper profile 20 is not initially attached to the 
thermoplastic film 12 by the attaching device 26, the upper leading flange 
28 has a tendency to flare out as the film enters the FFS machine and is 
fed over the forming collar 34, as shown in FIG. 3. The result of this 
flaring is that the unsecured upper leading flange 28 has a tendency to 
either jam the FFS machine or to become caught on the machine and thereby 
cause the upper profile 20 to detach from the lower profile 22. 
While the zipper strip 16 can be made without a leading flange 28 on the 
upper profile 20 in order to avoid this problem, the absence of the upper 
leading flange and its subsequent attachment to one of the bag walls in 
the FFS machine can result in poor zipper opening mechanics and a weak 
seal between the zipper strip and the completed bag. A four-flange seal, 
where all four zipper flanges are sealed to the bag, is the best and most 
secure method of attaching the zipper. 
SUMMARY OF THE INVENTION 
It is, therefore, the object of the present invention to overcome the 
aforementioned flaring problem so that zipper strips having four flanges 
can be used to reliably and efficiently make transverse-zippered 
reclosable bags on FFS machines. 
The present invention achieves the aforementioned object by providing a 
funnel which is attached to the FFS machine filling tube above the forming 
collar. The funnel guides the upper profile as the transverse 
zipper-equipped thermoplastic film is fed over the forming collar and 
wrapped around the filling tube, thus preventing the upper leading flange 
from flaring out. 
The present invention will now be described in more complete detail with 
frequent reference being made to the figures identified below in which 
identical numerals represent identical elements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 4 shows a perspective view of the forming collar 34 and filling tube 
36 of a typical FFS machine, such as the FFS machine of FIG. 1. In 
accordance with the present invention, a funnel 52 is attached to the 
filling tube 36 above the forming collar 34. 
As shown in detail in FIG. 5, which shows a cross section of the forming 
collar 34, filling tube 36 and funnel 52 of FIG. 4, the funnel 52 is 
shaped to guide the upper leading zipper flange 28 over the forming collar 
34 so as to maintain the substantial parallelism of the upper leading 
flange 28 and the lower leading flange 29. In this manner, the upper 
leading flange 28 is prevented from flaring out and jamming the FFS 
machine or getting caught in the FFS machine and causing the upper profile 
20 to detach from the lower profile 22 as the thermoplastic film 12 is fed 
over the forming collar 34 and around the filling tube 36. 
The funnel 52 is provided with a skirt 54 having a lower surface 56 for 
correcting any initial flaring of the upper leading flange 28 which may 
have been present during the initial attachment of the zipper strip 16 to 
the thermoplastic film 12; a main body 58 having a lower surface 60 which 
follows the shape of the forming collar 34 and which guides the upper 
leading flange 28 over the forming collar 34; and a base 62 for attaching 
the funnel 52 to the filling tube 36. 
In those situations where the zipper strip 16 is provided with a slider to 
facilitate the opening and closing of the zipper strip 16, a groove 64 may 
be provided in the lower surface 56, 60 of the funnel 52 for guiding the 
slider. Alternatively, a groove 66 may be provided in the forming collar 
34, as shown in FIG. 6 in place of or in addition to the groove 64. 
Further, even if one or both of the front flanges of the zipper profiles 
were eliminated (as may be possible in the case of a zipper provided with 
a slider), the funnel 52 would assist in maintaining the parallelism of 
the upper and lower profiles as the film material passes over the forming 
collar. 
An FFS machine modified in accordance with FIGS. 4 and 5 operates 
identically to the FFS machine of FIG. 1, with the exception of the 
guiding action provided by the funnel 52. 
Thus, the thermoplastic film 12 is paid off from the continuous roll 
thereof 14 in increments equal to the length of the bags which will 
ultimately be formed from the film 12 in the FFS machine 10. Each time the 
film 12 comes to rest, a zipper strip 16 is positioned on the film 12 
transverse to the longitudinal axis by the positioning device 18 with the 
upper profile 20 on top of the lower profile 22. The zipper strip 16 is 
then initially attached to the thermoplastic film 12 by the attaching 
device 26 by sealing or tacking the lower leading flange 29 thereto. 
At the FFS machine 10, the thermoplastic film 12 is fed downwardly over the 
forming collar 34 and folded around filling tube 36, with the upper 
leading flange 28 of each zipper strip 16 being guided by the funnel 52 so 
that the upper leading flange 28 does not flare out and jam the machine or 
cause the profiles to detach from one another. 
The edges of the film are then brought together and pressed together by the 
rollers 38 and welded together by the heater bars 40 to form the 
longitudinal back seal 42. Contents may then be dropped through the tube 
36. 
After introduction of the contents, the top of the bag is completed by the 
action of cross seal jaws 48, which (1) finally seal the leading flanges 
28, 29 of the profiles to front and back bag walls without sealing the 
leading flanges 28, 29 to each other; (2) seal the trailing flanges 30, 31 
of the zipper strip to the front and back bag walls without sealing the 
trailing flanges 30, 31 to each other; (3) seal the top of the bag to form 
a pilfer evident seal 50; (4) make the lower seal 46 for the succeeding 
bag; and (5) cut the completed bag 44 from the film 12. 
Thus, through use of the funnel of the present invention, zipper strips 
having four flanges may be reliably and efficiently used to make 
transverse-zippered reclosable bags on FFS machines. 
Modifications to the above would be obvious to those of ordinary skill in 
the art, but would not bring the invention so modified beyond the scope of 
the appended claims.