Note: Descriptions are shown in the official language in which they were submitted.
CA 02373792 2001-11-09
WO 00/76352 PCT/US99/13248
1
CLOSURE DEVICE
FIELD OF THE INVENTION
The present invention relates generally to closure
devices and, more particularly, to interlocking fastening
strips that are occluded and deoccluded by a slider. The
inventive closure devices may be employed in traditional
fastener areas, and is particularly well suited for
fastening flexible storage containers, including plastic
bags.
BACKGROUND OF THE INVENTION
The use of closure devices for fastening storage
containers, including plastic bags, is generally well
known. Furthermore, the manufacture of closure devices
made of plastic materials is generally known to those
skilled in the art, as demonstrated by the numerous
patents in this area.
A particularly well-known use for closure devices is
in connection with flexible storage containers, such as
plastic bags. In some instances, the closure device and
the associated container are formed from thermoplastic
materials, and the closure device and the side walls of
the container are integrally formed by extrusion as a
single piece. Alternatively, the closure device and side
walls of the container may be formed as separate pieces
and then connected by heat sealing or any other suitable
connecting process. In either event, such closure devices
are particularly useful in providing a closure means for
retaining matter within the bag.
Conventional closure devices typically utilize mating
fastening strips or closure elements which are used to
CA 02373792 2001-11-09
WO 00/76352 PCT/US99/13248
2
selectively seal the bag. With such closure devices,
however, it is often difficult to determine whether the
fastening strips are fully occluded. This problem is
particularly acute when the strips are relatively narrow.
Accordingly, when such fastening strips are employed,
there exists a reasonable likelihood that the closure
device is at least partially open.
Such fastening strips devices are also particularly
difficult to handle by individuals with limited manual
dexterity. Thus, in order to assist these individuals
and for ease of use by individuals with normal dexterity,
the prior art has also provided sliders for use in
opening and closing the fastening strips, as disclosed,
for example, in U.S. Patent Nos. 4,199,845, 5,007,142,
5,007,143, 5,010,627, 5,020,194, 5,070,583, 5,283,932,
5,301,394, 5,426,830, 5,431,760, 5,442,838, and
5,448,808. Many of these sliders include a separator
which extends at least partially between the fastening
strips. When the slider is moved in an appropriate
direction towards one end of the fastening strips, the
separator divides the fastening strips and opens the bag.
Once the fastening strips are separated, the fastening
strips can be relocked if desired by moving the slider in
the opposite direction toward the other end of the
fastening strips to reclose the bag.
One problem associated with using sliders is that
the slider can cause the bags to leak. In particular,
the separator of the slider can cause an unoccluded gap
between the fastening strips when the slider is at the
end of the bag when the bag is supposed to be fully
closed. The gap may allow the bag to leak. Leaky bags
are a disadvantage in many of the applications of
closable plastic bags. For example, leaky bags will not
store liquids unless the bag is properly oriented. Leaky
bags can often cause a mess and/or damage to other items
when liquids leak from the bags. If the bags are used
CA 02373792 2001-11-09
WO 00/76352 PCTIUS99/13248
3
for foods for refrigerator storage, leaky bags will
communicate air in and out of the bag which can cause
premature spoilage of the food inside the bag or the
contents in the bag can undesirably generate an odor into
the air inside the refrigerator.
SUMMARY OF THE INVENTION
The inventive leak-proof closure device is intended
for use with a storage container which includes a pair of
complementary sheets or opposing flexible side walls, such
as a plastic bag. The closure device includes
interlocking fastening strips disposed along respective
edge portions of the opposing side walls, and a slider
slidably disposed on the interlocking fastening strips.
The slider facilitates the occlusion of the fastening
strips when moved towards a first end thereof. The
slider includes a separator that facilitates the
deocclusion of the fastening strips when moved towards a
second end thereof. The fastening strips are sealingly
secured together at the first and second ends to prevent
leakage from the container or bag. In accordance with
the present invention, a second seal is provided in
proximity to the first end that fixes the fastening
strips together. The second seal prevents the formation
of a gap at the first end by the separator when the
fastening strips are fully closed and to thereby provide
a leak-proof container.
According to an aspect of one embodiment, the second
seal and the seals at the first and second ends are
accomplished by heat sealing, ultrasonic sealing or other
similar process that melts the plastic material of the
fastening strips together. This may be accomplished in
one heat sealing operation. In one embodiment, there is
an unmelted portion between the second seal and the first
end to prevent the slider from being removed from the
CA 02373792 2007-02-28
4
fastening strips in the vertical Z axis from the first end.
In one aspect, the present invention resides in a
closure device, comprising: first and second interlocking
fastening strips arranged to be interlocked over a
predetermined X axis between first and second ends, the
fastening strips being secured together at the first and
second ends; a slider slidably disposed on the fastening
strips for movement between the first and second ends, the
slider facilitating occlusion of the fastening strips when
moved towards the first end, the slider including a
separator disposed intermediate the fastening strips, the
separator facilitating the deocclusion of the fastening
strips when the slider is moved towards the second end; a
second seal sealing the fastening strips together in close
proximity to the first end, the second seal disposed in
relation to the slider to allow the slider, when disposed
at the first end, to move toward the second end without
engaging the second seal; and wherein the separator is
separated by a clearance gap from the second seal so that
the separator easily clears the second seal when the slider
moves toward the first end.
In another aspect, the present invention resides in a
container, comprising: first and second sidewalls joined
at seams to form a compartment with an opening; first and
second interlocking fastening strips respectively connected
to the first and second side walls at the opening, the
fastening strips being arranged to be interlocked over a
predetermined X axis between first and second ends for
completely closing the opening to thereby provide a leak-
proof container, the fastening strips being secured
together at the first and second ends; a slider slidably
CA 02373792 2007-02-28
4a
disposed on the fastening strips for movement between the
first and second ends, the slider facilitating occlusion of
the fastening strips when moved towards the first end, the
slider including a separator disposed intermediate the
fastening strips, the separator facilitating the
deocclusion of the fastening strips when the slider is
moved towards the second end; a second seal sealing the
fastening strips together in close proximity to the first
end, the second seal disposed in relation to the slider to
allow the slider, when disposed at the first end, to move
toward the second end without engaging the second seal; and
wherein the separator is separated by a clearance gap from
the second seal so that the separator easily clears the
second seal when the slider moves toward the first end.
In yet another aspect, the present invention resides
in a method of manufacturing a closure device, comprising:
arranging first and second interlocking fastening strips to
be interlocked over a predetermined X axis between first
and second ends; securing the fastening strips together at
the first and second ends; slidably disposing a slider on
the fastening strips for movement between the first and
second ends, the slider facilitating occlusion of the
fastening strips when moved towards the first end, the
slider including a separator disposed intermediate the
fastening strips, the separator facilitating the
deocclusion of the fastening strips when the slider is
moved towards the second end; sealing the fastening strips
together in close proximity to the first end to define a
second seal, the second seal disposed in relation to the
slider to allow the slider, when disposed at the first end,
to move toward the second end without engaging the second
seal; and wherein the separator is separated by a clearance
CA 02373792 2007-02-28
4b
gap from the second seal so that the separator easily
clears the second seal when the slider moves toward the
first end.
These and other features and advantages of the present
invention will become more readily apparent upon reading
the following detailed description of exemplified
embodiments and upon reference to the accompanying drawings
herein.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of a container according
to the present invention in the form of a plastic bag;
Fig. 2 is a top view of the container in Fig. 1;
Fig. 3 is a fragmentary side view of the container in
Fig. 1, with the slider positioned in an intermediate
position;
Fig. 4 is a fragmentary side view of the container in
Fig. 1 with the slider at the end;
Fig. 5 is a partial cross-sectional view of the
fastening strips taken along line 5-5 in Fig. 4;
Fig. 6 is a partial cross-sectional view of exemplary
fastening strips;
Fig. 7 is a top view of the slider in Fig. 2;
Fig. 8 is a bottom view of the slider in Fig. 2;
CA 02373792 2007-02-28
4c
Fig. 9 is a rear view of the slider in Fig. 2;
Fig. 10 is a front view of the slider in Fig. 2;
CA 02373792 2001-11-09
WO 00/76352 PCT/US99/13248
Fig. 11 is a section view of Fig. 2 taken about line
11-11.
Fig. 12 is a section view of Fig. 2 taken about line
5 12-12.
Fig. 13 is a section view of Fig. 2 taken about line
13-13.
Fig. 14 is another embodiment of the closure device
of the present invention.
Fig. 15 is a perspective view of a heat sealing tool
which may be used to secure the fastening strips of the
present invention.
Fig. 16 is a fragmentary side view of bags and
fastening strips that have been sealed with the tool of
Fig. 15.
While the present invention will be described and
disclosed in connection with certain embodiments and
procedures, the intent is not to limit the present
invention to these embodiments and procedures. On the
contrary, the intent is to cover all such alternatives,
modifications, and equivalents that fall within the
spirit and scope of the present invention as defined by
the appended claims.
DESCRIPTION OF THE EMBODIMENTS
Figs. 1-4 illustrate a container in the form of a
plastic bag 120 having a sealable closure device 121. The
bag 120 includes side walls 122, 123 joined at seams 125,
126 to form a compartment sealable by means of the closure
device 121. The closure device 121 comprises first and
second fastening strips 130, 131 and a slider 132.
CA 02373792 2001-11-09
WO 00/76352 PCT/US99/13248
6
The fastening strips 130, 131 and the slider 132
have a longitudinal X axis 102 and a transverse Y axis
104 which is perpendicular to the longitudinal X axis
102. Also, the fastening strips have a vertical Z axis
106 which is perpendicular to the longitudinal X axis 102
and which is perpendicular to the transverse Y axis 104.
The fastening strips 130, 131 are adapted to be
interlocked between a first end 127 and a second end 128.
The fastening strips 130, 131 are secured together at the
first and second ends 127, 128 to form end seals. As
shown in the figures, the first and second ends 127, 128
preferably include melted portions 135, 137, in which the
fastening strips 130, 131 are melted together by heat
sealing, ultrasonic sealing or other operation to form the
end seals. The first and second ends 127, 128 may
alternatively be secured together by plastic clamps, or
other means.
In accordance with the present invention, a second
seal 129 that secures part of the fastening strips 130,
131 together is provided in close proximity to the first
end 127. The second seal 129 is accomplished by heat
sealing, ultrasonic sealing or other welding operation,
but may alternatively be accomplished by any other method
that binds the fastening strips together in proximity to
the first end 127. For example, the second seal may be
created by using an adhesive, or by mechanically crimping,
such as, by cold forming. Referring to Fig. 3, the second
seal is disposed in close proximity to the bottom edge 115
of the fastening strips 130, 131 and extends upward in the
vertical Z axis to a point 118 which is between the bottom
and top edges 115, 117 of the fastening strips. An
unsecured portion 119 of the fastening strips 130, 131 may
be disposed between the melted portion 135 of the first
end 127 and the second seal 129. In one embodiment, the
unsecured portion 119 is an unmelted portion.
CA 02373792 2007-02-28
7
The melted portion 135 of the first end 127 is wider
near the top edge 117 of the fastening strips and narrower
near the bottom edge 115 of the fastening strips. This
leaves an unmelted triangular shaped portion 124 near the
bottom edge 115 of the first end 127. Similarly, the
melted portion 137 of the second end 128 is also wider
near the top edge 117 of the fastening strips and narrower
near the bottom edge 115 of the fastening strips.
Similarly, this leaves an unmelted triangular shaped
portion near the bottom edge 115 of the second end 128.
The slider 132 is slidably mounted on the fastening
strips 130, 131 for movement between the first and second
ends 127, 128. In use, the slider 132 facilitates the
occlusion and deocclusion of the interlocking fastening
strips 130, 131 when moved in the appropriate direction
along the longitudinal X axis 102 of the fastening strips
130, 131. In particular, the slider 132 facilitates the
occlusion of the interlocking fastening strips 130, 131
when moved towards a first end 127 thereof, and
facilitates the deocclusion of the interlocking fastening
strips 130, 131 when moved towards a second end 128
thereof. When the slider 132 is moved in an occlusion
direction, as indicated by reference numeral 114 in Figs.
1 and 2, closure of the fastening strips 130, 131 occurs.
Conversely, when the slider 132 is moved in a deocclusion
direction, as indicated by reference numeral 116,
separation of the fastening strips 130, 131 occurs.
The interlocking fastening strips may be of any type
or form including, for example: (1) U-channel fastening
strips as best shown herein at Figs. 5 and 6; (2)
"arrowhead-type" fastening strips, as disclosed in U.S.
Patent Nos. 5,007,142 and 5,020,194; (3) "profile"
fastening strips, as disclosed in U.S. Patent No.
5,664,299; and/or (4) rolling action fastening strips as
disclosed in U.S. Patent 5,007,143.
CA 02373792 2007-02-28
8
An illustrative example of the type of closure device
that may be used with the present invention is shown in
Fig. 5. The fastening strips include a first fastening
strip 130 with a first closure element 136 and a second
fastening strip 131 with a second closure element 134.
The first closure element 136 engages the second closure
element 134. The first fastening strip 130 may include an
upper flange 163 disposed at the upper end of the first
fastening strip 130 and a lower flange 167 disposed at the
lower end of the first fastening strip 130. Likewise, the
second fastening strip 131 may include an upper flange 153
disposed at the upper end of the second fastening strip
131 and a lower flange 157 disposed at the lower end of
the second fastening strip 131. The upper flanges 163,
153 include a straight portion 166, 156 and an angled
portion 168, 158. The angled portion 168, 158 is at an
approximately 120 degree angle to the straight portion
166, 156. As shown in Fig. 5, the side walls 122, 123 of
the plastic bag 120 may be attached to the lower flanges
167, 157 of their respective fastening strips 130, 131 by
conventional manufacturing techniques. As shown in Fig.
6, the side walls 122, 123 of the bag 120 may also be
attached to the outside surfaces of their respective
fastening strips 130, 131.
Referring to Figs. 5 and 6, the second closure
element 134 includes a base portion 138 having a pair of
spaced-apart parallely disposed webs 140, 141, extending
from the base portion 138. The webs 140, 141 include hook
closure portions 142, 144 extending from the webs 140, 141
respectively, and facing towards each other. The hook
closure portions 142, 144 include guide surfaces 146, 147
which serve to guide the hook closure portions 142, 144
for occluding with the hook closure portions 152, 154 of
the first closure element 136.
CA 02373792 2001-11-09
WO 00/76352 PCT/US99/13248
9
The first closure element 136 includes a base portion
148 including a pair of spaced-apart, parallely disposed
webs 150, 151 extending from the base portion 148. The
webs 150, 151 include hook closure portions 152, 154
extending from the webs 150, 151 respectively and facing
away from each other. The hook closure portions 152, 154
include guide surfaces 145, 155, which generally serve to
guide the hook closure portions 152, 154 for occlusion
with the hook closure portions 142, 144 of the second
closure element 134. The guide surfaces 145, 155 may also
have a rounded crown surface. In addition, the hook
closure portions 144, 154 may be designed so that the hook
closure portions 144, 154 adjacent the interior of the
container provide a greater resistance to opening the
closure device 121.
As shown in Figs 1-6, the base portions 138, 148 of
the closure elements 134, 136 also have respective guide
rails 139, 143 that extend lineally along the longitudinal
X axis 102. As shown in Fig. 5, the rails 139, 143 may be
integrally formed with the fastening strips. As shown in
Fig. 6, the rails 139, 143 may also be formed as an
outward ridge on the surface of the bag sidewalls 122, 123
by conventional manufacturing techniques. In one
embodiment, the guide rails 139, 143 are disposed in close
proximity to the bottom edge 115 and run through the
second seal 129, but may be disposed at any location
between the top and bottom edges 115, 117. Referring to
Figs. 1-3, the guide rails 139, 143 are disrupted at the
melted portions 135, 137 and at the second seal 129 by the
melting process that secures the fastening strips 130, 131
together at those locations.
Referring to Figs. 1-4 and 7-10 there is illustrated
an exemplary slider 132 for use with the fastening strips.
Referring to Figs. 7-10, the slider 132 includes a housing
160 and an attaching means 162. The housing 160 may
CA 02373792 2001-11-09
WO 00/76352 PCT/US99/13248
include a top portion 170, a first side portion 174, and a
second side portion 176. The top portion 170 provides a
separator 172 having a first end 190 and a second end 192
where the first end 190 is wider than the second end 192.
5 The separator 172 is generally triangular in shape as
shown in Fig. 8.
Referring to Figs. 8-10, the separator 172 has a
first surface 180 at the first end 190 and a second
10 surface 181 at the second end 192. The separator 172 has
a bottom surface 182. Also, the separator 172 has a first
side wall 183 and a second side wall 184 as shown in Fig.
8. The side walls 183, 184 generally angle inwardly from
the first end 190 to the second end 192. The side walls
183, 184 also angle outwardly from the bottom surface 182
to the top portion 170 as shown in Figs. 9 and 10.
The top portion 170 of the slider merges into the
first side portion 174 and the second side portion 176.
The first side portion 174 has a first grip 196 and a
first occlusion member 200. Similarly, the second side
portion 176 has a second grip 198 and a second occlusion
member 210. The first grip 196 and the second grip 198
extend laterally along the outer surfaces of the side
portions 174, 176 and provide inwardly protruding radial
gripping surfaces designed to correspond to the contour of
a person's fingertips as viewed in Figs. 1, 7 and 8. The
first and second grips 196, 198 facilitate grasping the
slider 132 during occlusion or deocclusion of the
fastening strips 130, 131. As shown in FIG. 1, the side
portions 174, 176 straddle the fastening strips 130, 131
when inserted thereon, with the occlusion members 200, 210
engaging the fastening strips 130, 131.
The occlusion members 200, 210 oppose one another and
force the fastening strips 130, 131 together to effectuate
occlusion of the fastening strips 130, 131 when the slider
is moved in the occlusion direction 114. The top portion
CA 02373792 2001-11-09
WO 00/76352 PCTIUS99/13248
11
170 may be thick to provide reinforcement between the
occlusion members 200, 210 to prevent the side portions
174, 176 from flexing during use. The occlusion members
200, 210 extend inward in the Y axis 104 from the side
portions 174, 176 of the slider 132 towards the center of
the slider. As viewed in Figs. 9 and 10, the occluding
members 200, 210 have inner surfaces 202, 204 which
generally angle outwardly from the top portion 170 to the
bottom of the slider 132 thus forming a V-shape. The
inner surfaces 202, 204 also have differently angled
portions, with respective lower portions 211, 212 that are
angled more with respect to the Z axis 106 than respective
upper portions 213, 214. The upper surface portions 213,
214 are substantially parallel with the Z axis 106 as
shown in FIGS. 9 and 10. Each inner surface 202, 204,
also provides a guide surface 215, 216, that offsets the
upper and lower portions 211, 212, 213, 214.
During movement of the slider 132 towards the second
end 128, the sidewalls 183, 184 of the separator 172
engage the upper flanges 156, 166 of the fastening strips
130, 131 to drive the upper ends of the fastening strips
130, 131 outward from one another. This causes
interlocked web members 141, 151, 140, 150 to deocclude
and separate which breaks the seal therebetween. During
the slider's movement toward the second end 128, the
narrower portion 192 of the separator will first engage
the fastening strips 130, 131 followed by progressively
wider portions including the widest portion 190 of the
separator. Thus, the separator 172 operates as a wedge to
drive the fastening strips 130, 131 outward from one
another.
The attaching means 162 includes a pair of front
flexible shoulders 230, 232, a pair of front legs 240,
242, a pair of rear flexible shoulders 250, 252, and a
pair of rear legs 260, 262. As viewed in Fig. 10, the
first side portion 174 merges into the first front leg 240
CA 02373792 2001-11-09
WO 00/76352 PCTIUS99/13248
12
through the first front shoulder 230. Likewise, the
second side portion 176 merges into the second front leg
242 through the second front shoulder 232. The front legs
240, 242 angle inwardly in the transverse Y axis 104
thereby forming a front slot 270 of substantially uniform
width as seen in Figs. 7 and 8.
Similarly, as viewed in Fig. 9, the first side
portion 174 merges into the first rear leg 260 through the
first rear shoulder 250. Also, the second side portion
176 merges into the second rear leg 262 through the second
rear shoulder 252. The rear legs 260, 262 angle inwardly
in the transverse Y axis 104 thus forming a rear slot 280
of substantially uniform width. In a relaxed state, the
legs 240, 242, 260, 262 of the slider 132 angle inwardly
away from their respective side portions 174, 176 to form
a void volume through which the legs 240, 242, 260, 262
may move outwardly in the transverse Y axis 104 during
attachment of the slider 132 onto the fastening strips 130
131.
Each of the legs 240, 242, 260, 262 also provides a
guide surface at their uppermost terminating end surface.
The combination of the guide surfaces 215, 216 of the
occlusion members 200, 202 and the guide surfaces of the
legs 240, 242, 260, 262 form a pair of parallel guide
tracks 221, 222 in the housing 160 aligned linearly with
the longitudinal X axis 102. The guide tracks 221, 222
appear as a pair of channels when viewed from the front
and rear in Figs. 9 and 10. The guide tracks 221, 222
slidably engage the guide rails 139, 143 when the slider
132 is attached on the fastening strips 130, 131 to retain
the slider 132 on the fastening strips 130, 131 in the Z
axis.
In order to attach the slider 132 to the fastening
strips 130, 131, the legs 240, 242, 260, 262 flex inward
and then outward when the slider is moved vertically over
CA 02373792 2007-02-28
13
the fastening strips 130, 131,in the Z axis. Once
attached, the legs 240, 242, 260, 262 engage the guide
rails 139, 143 to retain the slider slidably on the
fastening strips 130, 131. It will be appreciated by
those skilled in the art that the slider 132 may be molded
from any suitable plastic material.
The slider facilitates proper orientation of the
fastening strips within the slider during operation.
Proper orientation of the fastening strips within the
slider is usually accomplished by providing legs which
support the respective fastening strips. The design of
the slider is further dictated by the configuration of
fastening strips utilized.
In accordance with the present invention, the second
seal 129 provides for a leak proof container or bag 120.
The second seal 129 resists the outward driving force of
the separator 172 to hold the fastening strips 130, 131
together in a sealing relationship in close proximity to
the first end 127. During movement of the slider 132
towards the first end from the position shown in Fig. 3 to
that in Fig. 4, the separator 172 moves over the second
seal 129. To prevent the legs 240, 242, 260, 262 of the
slider 132 from disengaging the guide rails 139, 143, the
width 270 of the second seal 129 (which disrupts the guide
rail shape) in the X axis 102 is less than the width 272
of the legs in the X axis 102. Thus, an unmelted portion
119 is provided between the first end 127 and the second
seal 129. For embodiments which do not use guide rails or
where the guide rails are disposed above the second seal,
the second seal may extend continuously along the bottom
edge of the fastening strips to the melted portion 135 of
the first end 127 without an unsecured or unmelted portion
119 therebetween.
As the slider 132 passes over the second seal 129,
the wider end 190 of the separator 172 is the first
CA 02373792 2001-11-09
WO 00/76352 PCTIUS99/13248
14
portion of the separator 132 that moves over the second
seal 129, as shown in Figs. 2-4, and 11-13. Referring to
Fig. 11, the wide end of the separator 172 bends or pivots
the fastening strips 130, 131 about the top end 118 of the
second seal 129. The resilient nature of the fastening
strips 130, 131 allows for the bending to occur, which
allows the slider 132 to pass over the second seal 129.
Furthermore, the lower closure portions 144, 154 in the
unmelted portion 119 remain occluded when the slider 132
passes over the second seal 129 and the slider is at the
end position. Also shown in Figs. 4 and 11 is that the
bottom surface 182 of the separator 172 is separated by a
clearance gap 274 from the top end 118 of the second seal
129 so that the separator 172 easily clears the second
seal 129.
Once the slider 132 is at the first end 127 as shown
in Fig. 4, the top portion 170 of the slider 132 and/or
the separator 172 of the slider 132 engage the melted
portion 135 at the first end 127 to prevent the slider 132
from moving further in the closing direction 114. Figs. 2
and 4 show the slider 132 in the end position of the
fastening strips 130, 131 near the seam 127. Figs. 11-13
illustrate occlusion of the fastening strips in the end
position. These figures demonstrate that the closure
device will have a leak proof seal when the slider is in
the end position. The leak proof seal is created even
though the separator extends between the flanges 153, 163.
As shown in Fig. 11, the second seal 129 seals the
bottom of the fastening strips 130, 131 together in
sealing relationship. The second seal 129 fuses the
bottom web members 141, 151 into a single mass. The
resilient nature of the fastening strips 130, 131 allows
the separator 172 to move past the second seal 129 while
preventing the wide end 190 of the separator 172 from
separating the second seal.
CA 02373792 2001-11-09
WO 00/76352 PCTIUS99/13248
The positions of the fastening strips are effected
not only by the forces acting upon them by the slider at a
particular location but are also effected by the position
of the fastening strips at locations before and after that
5 particular location. Specifically, with respect to the
position of the inner closure portions 141, 151 in Fig.
12, the position of the inner closure portions 141, 151 is
effected by the second seal 129. At the second seal 129,
the fastening strips 130, 131 are melted together which
10 effectively occludes the fastening strips. This occlusion
of the fastening strips 130, 131 at the second seal 129
prevents separating action of the separator finger 172
from deoccluding the inner closure portions 141, 151 at
the locations in Figs. 12 and 13. Thus, the inner closure
15 portions 141, 151 remain occluded even though the
separator finger 172 is attempting to deocclude the inner
closure portions. Consequently, the inner closure
portions 141, 151 remain occluded through the length of
the fastening strips and establish a leak proof seal
through the length of the fastening strips when fully
occluded. Furthermore, the length of the unsecured or
unmelted portion 119 is selected to be short enough to
prevent the wide end 190 of the separator 172 from
deoccluding or forming a gap in the unsecured or unmelted
portion 119 of the fastening strips.
In viewing Figs. 2 and 4, it can be seen that the
rear legs 260, 262 move past the melted portion 135. The
triangular shaped bottom unmelted portion 124 receives the
legs 260, 262 and advantageously still provides the guide
rails 139, 141 to prevent the slider 132 from being
removed in the vertical Z axis 106 from the first end 127.
As shown in Figs. 1-3 the second seal 129 has a
length that extends parallel with the Z axis. In the
alternative embodiment of Fig. 14, it will be appreciated
that other configurations or alignment of the second seal
are available and included by the invention, such as a
CA 02373792 2001-11-09
WO 00/76352 PCT/US99/13248
16
second seal 329 which is angled with respect to the Z axis
106. The second seal 329 is at an angle 330 which is 30
degrees from the vertical Z axis 106. The second seal may
also be at an angle 330 in a first range of 0-80 degrees
or a second range of 30-60 degrees.
Turning to Figs. 15 and 16, there is shown a heat
sealing tool 420 for forming the seal 129 at the first end
127 and for forming the melted portions 135, 1137 at the
first and second ends 127, 1128 of two different bags 120,
1120. The tool 420 includes a body 422 having a cavity
424 and a stamping face 426. The cavity 424 is
connectable to the shaft of a machine for holding the tool
420 in alignment. The stamping face 426 includes a first
fan shaped raised member 430 for forming melted portions
135, 1137 of the first and second ends 127, 1128 as well
as a second raised portion 432 for forming the second seal
129. The heat sealing tool 420 conducts enough heat to
melt the fastening strips 130, 131 together at the
selected locations.
The adjacent bags 120, 1120 shown in Fig. 16 show
adjacent fastening strips that have been heat sealed by
the tool 420 illustrated in Fig. 15. As shown, the tool
420 is applied to two adjacent bags 120, 1120 before the
bags 120, 1120 have been separated at the future location
of the seams 125, 1126. The seams 125, 1126 will be
formed after the tool 420 has been applied to the
continuous strip which creates the bags 120, 1120. An
advantage of the heat sealing tool of Fig. 15 is that the
second seal 129 is formed at the same time as the melted
portions 135, 1137 of adjacent fastening strips for two
different bags 120, 1120. This provides for an easy, less
expensive manufacturing process which provides a reliable
way for providing a container or bag.
Although several interlocking fastening strip
embodiments have been specifically described and
CA 02373792 2001-11-09
WO 00/76352 PCT/US99/13248
17
illustrated herein, it will be readily appreciated by
those skilled in the art that other kinds, types, or forms
of fastening strips may alternatively be used without
departing from the scope or spirit of the present
invention.
The interlocking fastening strips may be manufactured
by extrusion through a die. In addition, the fastening
strips may be manufactured to have approximately uniform
cross-sections. This not only simplifies the
manufacturing of a closure device, but also contributes to
the physical flexibility of the closure device.
Generally, the interlocking fastening strips may be
formed from any suitable thermoplastic material including,
for example, polyethylene, polypropylene, nylon, or the
like, or from a combination thereof. Thus, resins or
mixtures of resins such as high density polyethylene,
medium density polyethylene, and low density polyethylene
may be employed to prepare the interlocking fastening
strips of the present invention. In most instances, the
fastening strips are made from low density polyethylene.
The selection of the appropriate thermoplastic material,
however, is related to the particular design of the
fastening strips, the Young's Modulus of the thermoplastic
material, and the desired elasticity and flexibility of
the strips.
When the fastening strips are used in a sealable bag,
the fastening strips and the films that form the body of
the bag may be conveniently manufactured from heat
sealable material. In this way, the bag may be
economically formed by using an aforementioned
thermoplastic material and by heat sealing the fastening
strips to the bag. In most instances, the bag is made
from a mixture of high pressure, low density polyethylene
and linear, low density polyethylene.
CA 02373792 2001-11-09
WO 00/76352 PCT/US99/13248
18
The fastening strips may be manufactured by extrusion
or other known methods. For example, the closure device
may be manufactured as individual fastening strips for
later attachment to the bag or may be manufactured
integrally with the bag. In addition, the fastening
strips may be manufactured with or without flange portions
on one or both of the fastening strips depending upon the
intended use of the closure device or expected additional
manufacturing operations.
Generally, the closure device can be manufactured in
a variety of forms to suit the intended use. The closure
device may be integrally formed on the opposing side walls
of the container or bag, or connected to the container by
the use of any of many known methods. For example, a
thermoelectric device may be applied to a film in contact
with the flange portion of the fastening strips or the
thermoelectric device may be applied to a film in contact
with the base portion of fastening strips having no flange
portion, to cause a transfer of heat through the film to
produce melting at the interface of the film and a flange
portion or base portion of the fastening strips. Suitable
thermoelectric devices include heated rotary discs,
traveling heater bands, resistance-heated slide wires, and
the like. The connection between the film and the
fastening strips may also be established by the use of hot
melt adhesives, hot jets of air to the interface,
ultrasonic heating, or other known methods. The bonding
of the fastening strips to the film stock may be carried
out either before or after the film is U-folded to form
the bag. In any event, such bonding is done prior to side
sealing the bag at the edges by conventional thermal
cutting. In addition, the first and second fastening
strips may be positioned on opposite sides of the film.
Such an embodiment would be suited for wrapping an object
or a collection of objects such as wires. The first and
second fastening strips should usually be positioned on
the film in a generally parallel relationship with respect
CA 02373792 2007-02-28
19
to each other, although this will depend on the intended
use.
The slider may be multiple parts and snapped
together. In addition, the slider may be made from
multiple parts and fused or welded together. The slider
may also be a one piece construction. The slider can be
colored, opaque, translucent or transparent. The slider
may be injection molded or made by any other method. The
slider may be molded from any suitable plastic material,
such as, nylon, polypropylene, polystyrene, acetal,
toughened acetal, polyketone, polybutylene terrephthalate,
high density polyethylene, polycarbonate or ABS
(acrylonitrile-butadiene-styrene). The selection of the
material may be determined by the characteristics to be
achieved by the slider.
From the foregoing it will be understood that
modifications and variations may be effectuated to the
disclosed structures - particularly in light of the
foregoing teachings - without departing from the scope or
spirit of the present invention. As such, no limitation
with respect to the specific embodiments described and
illustrated herein is intended or should be inferred.
Indeed, the following claims are intended to cover all
modifications and variations that fall within the scope
and spirit of the present invention.
