Note: Descriptions are shown in the official language in which they were submitted.
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A GUIDE MECHANISM FO~ BAG FILM HAVING FASTENER ELEMENTS
AND A FORM, FILL AND SEAL PACKAGING APPARATUS
This invention relates to a mechanism for
guiding a continuous film web of a plastic material
having reclosable fastener element~ on respective
opposing plies of the film web, and more particularly
to a mechanism for guiding and separating the
interlocked fastener elements extending along the edges
of the film web. The invention also relates to a f`orm,
fill and seal packaging apparatus employing the guide
mechanism.
Bags of various types have been used for
packaging a wide variety of products such as, for
example, cereals, cookies~ potato chips and the like.
These bags can serve as the external package for the
products, or can be lnserted into boxes a~ a liner for
the boxes. When packaging perishable products such as
cereal, cookies and potato chips, the bags should be
sealed to preserve the product contained therein by
preventing the co~mingling of outside air and moisture
with the product in the bags.
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Conventional sealed bags (such as most cereal
bags and potato chip bags) have se21s which are formed
by gluing together or heat sealing together a pair of
opposed edges of the bags. One problem with such
conventional sealed bags is that they cannot be
resealed a~ter being opened. Thus 9 once the bag is
opened, the user cannot prevent the unwanted intrusion
of outside air and moisture into the bag.
Usually, reclosable bags include a pair of
fastener elements (such as a pair of rib and groove
profiles), which the user fastens together after
opening to thereby effectively seal the contents of the
bag from the intrusion of unwanted air and moisture.
One example of such a reclosable or "zippered" bag is
the ZIPLOC~ brand food storage bag manufactured by The
Dow Chemical Company.
Both conventional and reclosable bags share a
common feature in that they are usually formed from a
continuous roll of a film web. This film web iq folded
over to form a pair of opposing plies forming a
generally tubular structure which can be filled with a
product. The tubular web is then subdivided
transversely into a plurality of individual bags.
Machines for forming and filling such ba~s from a
continuous film web are known.
U.S. Patent No. 3,815,317 (Toss) relates to a
form, fill and seal apparatus for use with zippered
bags. A continuous web of film is fed to the
ayparatus. The continuous web has interlocked fastener
profiles. The profiles are disengaged, and the film
spread apart to remove wrinkles. A pin unlocks the
profiles, while a guide device holds the profiles
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apart. The profiles are rejoined as they are pinched
by closlng rolls. The interlocked film is then cross-
sealed and filled through the remaining open side. The
final seam i~ then sealed and severed to provide the
final structure. It should be noted that the
mechanisms in the Toss structure which unlock and
reclose the profiles do so for the purpose of removing
wrinkles or folds from the film. The filling of the
bag itself is accomplished through an open side of the
bag. During the filling of the bag, the profiles are
closed.
U.S. Patent Nos. 4,024,010 and 4,094,729
(Boccia) relate to an apparatus wherein two opposing
film layers with interlocking rib and groove profiles
on opposing faces are separated so that a heat sealing
of the side seams can be accomplished only in those
areas where the profiles remain interlocked. A
separating finger opens the interlocked fastener
elements. Grooves on the top and bottom of the
separating finger are provided for maintaining the
profiles elements in alignment.
One difficulty encountered in bag forming,
filling and sealing operations resides in maintaining
the film web from which the bags are cut in a proper
lateral alignment as the film web travels through the
machine. This problem is especially acute in the
forming, filling and sealing of reclosable bags having
fastener elements. The term "bag film" herein denotes
a film web having fastener elements positioned along
their edges.
Typically, a bag film is wound on a roll in a
helical pattern, such that the fastener elements of
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adjacent layers on the roll are offset laterally from
each other. The bag film is usually wound on a roll in
this manner in order to form a roll havin~ a more
constant diameter throughout its width If the bag
film were not wound in this helical manner, the extra
thickness provided by the fastener elements would cause
the ~ag film roll to be much thicker in that area
wherein the fastener elements are placed. The helical
winding of the bag film makes it difficult, however, to
draw the bag film from the roll in a proper lateral
alignment for entry into the forming, filling and
sealing machine. As the bag film should be properly
laterally aligned before the bag film is fed into the
machine, means should be provided for laterally
aligning the bag film prior to the bag film being fed
into the forming, filling and sealing portions of the
machine.
It is therefore an object of this invention to
provide a guide mechanism for providing uninterrupted
guidance of a reclosable bag film having interlocked
fastener elements extending along the edges of the film
web. The guide mechanism is positioned inside of and
between a pair of opposing plies of a folded-over Eilm
web for providing uninterrupted guidance of the bag
film through a forming station. The guide mechanism
comprises a first guide which engages an interior
surface of the bag film and a second guide which
3 engages a pair of interlocked fastener elements on the
opposing plies of the bag film. A separating means is
positioned along the path traveled by the bag film for
separating the interlocked fastener elements as the bag
film is advanced. A support arm is provided for
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supporting the first and second guides and the
separating means.
It is a further object of the present invention
to provide a form, fill and seal packaging apparatus
comprising means for supplying a continuous bag film
having reclosable fastener elements on respective
opposing plies of the film web, and means for feeding
the bag film through a ~illing station for supplying a
predetermined amount of a product to the bag film.
Guide means are provided immediately preceding the
filling station and positioned inside the bag film for
providing uninterrupted guidance of the bag film
through the filling station. A separating means
precedes the filling station for separating the
interlocked fastener elements. The packaging apparatus
also includes means for pressing the fastener elements
together in an interlocking relationship and means for
laterally sealing the bag film to form a bag assembly
having first and second side seams. Means are also
provided for severing the bag assembly from the filmO
Preferably, the guide means includes a support
arm and a bracket member connected to the support arm
and disposed between the plies of the film web. A
first guide wheel is rotatably coupled to the bracket
member for engaging an interior surface of the bag
film, and a second guide wheel is rotatably coupled to
the bracket member for engaging the fastener elements.
The separating means can comprise a separating edge
which is disposed on the support arm.
Thus, a feature of the present invention is
that a guide mechanism is provided which is disposed in
the interior of the folded-over plies of the film web
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between the bottom of the web (i.e~, the bight) and the
interlocked fastener elements of the film web. By
being plzced inside the film web between the bottom and
the interlocked fastener elements. the guide ~echanism
can properly laterally align the bag film so that the
film is correctly placed for the feeding into the
filling portion of the packaging machine.
Another feature of the present invention is
that the ~uide mechanism can include a first rotatable
guide wheel for engaging the bottom of the film (i.e. 9
the bight) and a second rotatable guide wheel for
engaging the fastener elements. The use of guide
wheels has the advantage of providing a relatively
frictionless engagement (in the direction of the path
of travel of the film) between the guide mechanism and
the wheel. This relatively frictionless engagement
reduces the guide mechanism's drag on the film. This
reduction in drag is especially helpful in facilitating
high speed packaging processes.
It is also a feature of the present invention
that the support arm for supporting the guide mechanism
immediately follows the guide wheels, and that the
support arm includes the means for separating the
interlocked f'astener elements. By positioning the
guide wheels so that they precede the separating means,
the guide wheels can engage the two opposed, inner
surfaces of the bag film. This inner surface
engagement of the film has the advantage of providing
an effective means for laterally aligning the film.
The placement of the separating means on the support
arm serves the dual functions of 1) supporting the
guide wheels and 2) disengaging the interlocked
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fastener elements to permit the passage of z filling
chute between the profiles.
Additional features and advantag~s o~ the
present invention will become apparent to Lhose skilled
in the art upon consideration of the following detailed
description of a preferred embodiment exemplifying the
base mode of carrying out the invention as presently
perceived.
Figure l is a perspective view of the form,
fill and seal packaging apparatus of the present
invention;
Figure 2 is a top plan view of the guide
mechanism of the present invention;
.i Figure 3 is a side view of the guide mechanism
of the present invention; and
Figure 4 is an exploded view of the guide
mechanism of the present invention.
A form~ fill and seal packaging machine
(apparatus) is shown in Figure l. A roll of bag film
lo for supplying a continuous web 16 of the film is
supported on a spindle 12 which is rotatably journaled
on a rack 14 for maintainlng the roll 10 above the
ground. The continuous web 16 of film is unwound from
the roll 10 and is fed into the packaging apparatus 8.
The web 16 is helica:lly wound onto the roll 10,
and as drawn from the roll 10 has a pair of opposed
film plies 18, 19. The opposed film plies 18, 19 are
continuou.s with each other at the bottom edge 20 (of
the finished bag 21) and are interlocked near the top
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ed~e 22 (o~ the finished bag 21) by fastener elements
comprising a ~emale profile 24 which is formed as a
part of ply 18 and a male profile 25 which is formed as
a part of ply 19. The fastener elements 24, 26 can be
5 similar to the fastener elements found on ZIPLOC~ brand
food storage bags manu~actured by The Dow Chemical
Company. The fastener elements 24, 26 permit the
finished bag 21 to be reclosed after opening.
From the roll 10, the web 16 is drawn upwardly
over a roller 28 by a feed mechanism (not shown) which
is disposed downstream in the path of travel of the web
16. Although roller 28 is shown as a single roller, it
preferably comprises a "dancer roll" system. The web
16 is then drawn through a guide mechanism 30 which
includes means for laterally aligning the web 16 and a
splitting edge 32 for disengaging the interlocked
fastener elements 24, Z6.
An idler roller 36 is disposed direckly
downstream of the path of travel of the web 16 from the
guide mechanism 30. The idler roller 36 is positioned
at about the same vertical height as the guide
mechanism 30 and is rotatably journaled on a spindle
38. After the fastener elements 24, 26 have been
disengaged by the splitting edge 32, both plies 18, 19
of the web 16 pass over the idler roller 36. Once the
web has passed over the idler roller 36, the web 16
travels generally vertically downwardly as indicated by
arrow A. Due to the action of the splitting edge 32,
the fastener elements 24, 26 are disengaged as the web
16 passes over idler roller 36 and begins its downward
travel.
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A slde arm filling station comprising a feed
chute 40 is provided for directing a product, such as
cereal flakes or pellets 42, into the interior of the
bag web 16. The feed chute 40 includes a generally
vartically extendin~ upper portion 44, an an~led median
portion 46 and a generally vertically extending lower
portion 50. The angled portion 46 passes between the
diqengaged fastener elements 24, 26 and into the
interior of the web 15. The lower portion 50 is
disposed ~etween the plies 18, 19 of the web 16.
A steering, joining and closing mechanism 54
for pressing together and reinterlocking the fastener
elements 24, 26 of the opposed plies 18, 19 is disposed
in the path of travel of the web 16 and is positioned
directly downstream of the angled portion 46. More
particularly, the mechanism 54 is disposed downstream
of that portion of the angled portion 46 of filling
chute 40 which passes between the fastener elements 24,
26. Although the mechanism 54 is disposed downstream
of the angled portion 46, it is also disposed at the
same general point in the direction of travel of the
web 16 as a portion of the lower portion 50 of the feed
chute 40.
A reciprocally moving 7 generally vertically
extending seal forming bar 56 is disposed downstream of
the mechanism 54. The bar 56 is provided for forming a
temporary "peel seal" 58. In the finished bag 21, the
peel seal 58 is formed interiorly of and generally
parallel to the fastener elements 24, 26. The peel
seal 58 can be unsealed by the user without destroying
the integrity of the fini~hed bag 21. The peel seal 58
helps to make the finished bag 21 more tamper
resistant. Preferably, the length of the bar 56 is
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approximately equal to the width o~ the fin.ished bag
21.
A reciprocally moving, generally horizontally
disposed seal forming means 60 having sealing bars 60a
and 6Cb is disposed below the open lower end 62 of the
feed chute 40. Preferably, seal ~ormin~ means 60 is
disposed at a distance ~rom the open lower end 62 of
the fe~d chute 40 which is approximately equal to the
width of one ~inished bag 21. Sealing bars 60a and 60b
are provided for laterally sealing to~ether the first
and second plies 18, 19 to form the side seals of the
finished bag 21.
A severing means 66 is disposed between sealing
bars 60a and 60b and is provided for severing the
intermittently sealed continuous web 16 into individual
finished bags 21.
The guide mechanism 30 of the present invent.ion
is more clearly shown in Figures 2 to 4. Thé mechanism
30 includes a support arm 74 for supporting the various
components of the guide mechanism 30. The support arm
74 can be connected to a portion (not shown) of the
form, fill and seal packaging apparatus 8, can be
supported by an independent stand tnot shown) or can be
formed to include an integral stand (not shown).
The support arm 74 includes a portion 76
disposed exteriorly of the film web, a portion 78
disposed interiorly of the film web 16 and an
intermediate portion 80. The intermediate portion 80
is disposed in the path of travel of the fastener
elements 24, 26 and passes between the fastener
elernents of the film web 16 as the web is advanced.
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An upper bracket member 84 and a lower bracket
member 86 are attached by screws 87 to the respective
upper surface 88 and lower surface 90 ol the interior
portion 78 of the support arm 74. The bracket members
84, 86 are disposed in a plane ~enerally parallel to
the pli-es 18, 19 of the film web and extend generally
upstream in the direction of travel of the web 16 Prom
the support arm 74.
The bracket members 84. B6 each include a
beveled peripheral lip 92 which extends along the
forward and side edges of the bracket members 84~ 86.
The beveled lips 92 facilitate the passage of the plies
18, 19 over the bracket members 84, 86, and reduce the
likelihood of the plies 18, 19 becoming snagged on the
respective bracket members 84, 86.
Each of the bracket members 84, 86 also include
a first rounded forward corner 98 and a second rounded
forward corner 100. The rounded corners 98, 100 and
the beveled lip 92 combine to form the guide mechanism
30 which is tapered about all web contacting edge
peripheries. This dual tapering helps to prevent the
plies 18, 19 from becoming snagged on the guide
mechanism 30.
A first guide wheel 102 is rotatably journaled
on an axle 104 to both the upper and lower bracket
members 84, 86 and is di~posed therebetween. The axis
about which the first guide wheel 102 rotates is
generally perpendicular to the plane of the plies 18,
19 oP the film web 16. The first guide wheel 102 is
sized and positioned so that its film engaging surface
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106 engages the bottom 109 of the interior surface o~
the ~ilm web 16.
A second guide wheel 109 is rotatably journaled
on an axle 110 to both the upper and lower bracket
members 84, 86 and is disposed therebetween. The axis
about which the second guide wheel 109 rotates is
parallel to the axis about which the first guide wheel
102 rotates~ with both being perpendicular to the plane
of the plies 18, 19 of the film web 16. The second
guide wheel 109 is sized and positioned so that its
film engaging surface 112 engages the interior surface
114 of the fastener elements 24, 26 while they are
interlocked. The second guide wheel 109 preferably
exerts a sufficient ~orce against the interior surface
114 of the fastener elements Z4, 26 to align the film
web 16 properly, without putting enough force on the
interior surface 114 of the fastener elements 24, 26 to
cause the fastener elements to become disengaged.
The film engaging surfaces 106, 112 of the
guide wheels 102, 109 are best shown in Figures 2 and 4
as being beveled ~urfaces each of which include a
2~ relatively larger beveled surface 116 and a relatively
smaller right cylindrical surface 116. Although
rounded or squared off film engaging surfaces can be
used, beveled film engaging sur.faces 106, 112 enhance
the performance of the first and second guide wheels
102, 109 and especially enhance the performance of the
second guide wheel 109. It has been found that the
beveled film engaging surface 112 can exert a
relatively greater force against the interior surface
114 of the fastener elements 24, 25 without
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disengaging the fastener elements than a rounded or
squared off ~ilm engaging surface.
The applicants have also found that the best
results are obtained by placing the larger surface 115
against the fastener element (female profile) 24. In
one testing session, the applicants found that b~
placing the fastener element 24 against the larger
be~eled surface 115, the fastener elements 24, 26 could
withstand an average of 18.8 pounds of force (84 N)
without becoming disengaged. When the fastener element
(male profile) 26 was placed against the larger beveled
surface 115, the fastener elements could withstand an
average of 9~3 pounds of force (41.4 N~ without
~ecoming disengaged. When a rounded film engaging
surface (i.e., without guide wheels) (not shown) was
employed, the applicants found that the fastener
elements 24, 26 could withstand an average of 9.8
pounds of force (43.6 N) without becoming disengaged.
This ability of a beveled film engaging surface
to exert increased force helps the guide mechanism 30
to perform its function of laterally aligning the film
web 16 without disengaging the fastener elements 24,
26. Although a beveled film engaging surface 106 can
be used with the first guide wheel 102, the
configuration of the film engaging surface 106 of the
first guide wheel 102 is not as important to the
performance of the guide mechanism 30 as the
configuration of the film engaging surface 112 of the
second guide wheel 109. Preferably, the guide wheels
102, 109 are constructed of a material such as
stainless steel.
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In an alternate embodiment ~not shown) the
guide wheels 102, 109 can be eliminated and the bracket
members 84, 86 can be sized and positioned to serve as
a stationary edge means for aligning the film web. In
such an embodiment. the first forward corners and sides
of the bracket members would engage the bottom 106 of
the interior surface of the film, and the second
forward corners and sides o~ the bracket ~embers would
engage the interior surface 114 of the fastener
elements. Similar to bracket members 8~, 86, the
bracket members of this alternate embodiment should
have a corner and edge configuration which provides the
guide mechanism with a forward portion tapered about an
axis both parallel and perpendicular to the plane of
the plies 18, 19 of the film web 16.
The splitting édge 32 is formed as a part of
the intermediate portion 80 of the support arm 74, and
comprises the forward edge 118 of the support arm 74
being beveled on its upper and lower surfaces.
Alternatively, the splitting edge 32 can comprise a
separable beveled member (not shown) which is mounted
to the intermediate portion 80 of the support arm 74.
In operation, the engagement of the first guide
wheel 102 with the bottom ~urface 108 of the film web
16 and the engagement oP the film engaging surface 112
of the second guide wheel 109 with the interior surface
114 of the fastener elements 24, 26 cooperate to place
the bag film 16 in its proper lateral alignment. The
rotatability of the guide wheels 102, 109 performs this
lateral alignment with a relatively small amount oP
frictional engagement~ thus reducing the drag of the
guide mechanism 30 on the film web 16. After the
second guide wheel 109 engages the interlocked fastener
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ele~ents 24, 26 to laterally align the film web 16? thefastener elemen~s 24, 2h are advanced to engage the
splitting edge 32, whereby they are disengaged.
In thi3 manner, it i5 possible to utilize the
interlocked fastener elements 24, 26 to laterally align
the film web 16 and to separate the fastener elements
after film web 16 has been aligned~ It has been found
by applicants that the system described above provides
an efficient guiding and splitting mechanism for a
forming, filling and sealing apparatus for 7ippered
bags.
Having described the invention in detail, and
by reference to the preferred embodiments thereof, it
will be apparent that modi~ications and variations are
possible without departing from the scope of the
invention defined in the appended claims.
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