Patent Publication Number: US-6220754-B1

Title: Closure device and slider

Description:
FIELD OF THE INVENTION 
     The present invention pertains to an interlocking closure device, and, more particularly, to a closure device with a slider. The closure device of the present invention may be employed in traditional fastener areas, and is particularly suited for use as a fastener for storage containers, such as plastic bags. 
     BACKGROUND OF THE INVENTION 
     The use of fastening devices for the closure of containers, including plastic bag bodies, is generally known. Furthermore, the manufacture of fastening devices made of plastic materials is generally known to those skilled in the art relating to closure devices, as demonstrated by the numerous patents in this area. 
     A particularly well-known use for fastening devices is in connection with flexible containers, such as bag bodies. The closure device and the associated container may be formed from thermoplastic materials, and the closure device and sidewalls of the container can be integrally formed by extrusion as a single piece. Alternatively, the closure device and sidewalls may be formed as separate pieces and then connected by heat sealing or any other suitable connecting process. The closure devices when incorporated as fasteners on bag bodies have been particularly useful in providing a closure means for retaining the contents within the bag body. 
     Conventional closure devices utilize mating male and female closure elements which are occluded. When conventional closure devices are employed, it often is difficult to determine when the male and female closure elements are occluded. This problem is particularly acute when the closure devices are relatively narrow. Accordingly, when conventional closure devices are employed, there exists a reasonable likelihood that the closure device is at least partially open. 
     The occlusion problem arises from the inability of a user to perceive when the male and female closure are occluded to form a seal between the contents of the bag and the environment external to the bag. A number of solutions to this problem have been attempted. For example, U.S. Pat. Nos. 4,186,786, 4,285,105, and 4,829,641, as well as in Japanese patent application No. 51-27719, disclose fasteners that provide a visual indication that the male and female closure elements are properly occluded. Specifically, a color change means for verifying the occlusion of the male and female members of the closure is provided wherein male and female members having different-colors are employed, and, upon occlusion, provide yet a different color. For example, the female member of the closure may be opaque yellow and the male member of the closure may be translucent blue. Upon occlusion of the male member and female member a composite color with a green hue results. This use of a color change greatly improves the ability of the user of the interlocking closure device to determine when the male and female members are occluded. 
     The change in color that is viewed when dissimilarly colored male and female members are occluded is demonstrated in a commercially available product sold under the trademark GLAD-LOCK (Glad-Lock is the registered trademark of The Glad Products Company of Oakland, California, formerly First Brands Properties, Inc., Danbury, Conn.). This color change effect may be enhanced by the incorporation of a color change enhancement member in the closure device, as disclosed in U.S. Pat. No. 4,829,641. 
     Color-changing closure devices are not a universal solution to the aforementioned problem of assuring full closure, however. For example, the color-change effect is imperceptible in the dark, thus mooting the color-change advantage of the closure devices when they are used under such conditions. In addition, sight-impaired or color-blind people may not be able to perceive the color-change effect. Accordingly, it would be desirable to provide a closure device that affords other indications of occlusion. 
     The prior art has attempted to furnish a fastener that provides a tactile or audible indication of occlusion. For example, U.S. Pat. Nos. 4,736,496, 5,138,750, 5,140,727, 5,403,094, and 5,405,478, as well as EP 510,797, disclose closure devices that allegedly provide a tactually or audibly perceptive indication of proper interlocking of the closure elements. It is said that, upon occlusion of the disclosed closure devices, a user is able to feel or hear that full closure is accomplished. For example, U.S. Pat. No. 4,736,946 discloses the use of additional ribs on either side of the closure elements. These ribs are said to give an improved “feel” to the closure, thus aiding a user in aligning the closure elements. 
     Such devices are difficult to handle by individuals who have limited manual dexterity. Thus, in order to assist these individuals and for ease of use by individuals with normal dexterity, the prior art has attempted to furnish a fastener that provides a reclosable fastener and a slider for opening and closing the fastener. For example, several U.S. Patents disclose fasteners with sliders. However many of these fasteners use either: (1) a separator finger which extends between the closure elements, such as U.S. Pat. Nos. 3,054,434, 3,115,689, 3,122,807, 3,230,593, 3,426,396, 3,713,923, 4,199,845, 4,262,395, 5,007,142, and 5,010,627 (FIGS. 9 and 10); or (2) the separator finger runs along a track above the closure elements, such as, U.S. Pat. Nos. 5,007,143, 5,010,627 (FIGS. 3-8), 5,020,194, 5,067,208, 5,070,583, 5,088,971, 5,131,121, 5,161,286, 5,283,932, 5,301,395, 5,426,830, 5,442,837 and 5,448,808. 
     With respect to fasteners which use a separator finger which extends between the closure elements, these fasteners do not provide a leak proof seal because the separator finger extends between the closure elements. With respect to the fasteners which run along a track, the fastener typically include slits, notches or another means to accommodate the separator finger in the end position. These means are used to achieve occlusion of the closure elements at the end position and thus attempt to achieve a leak proof seal. For example, U.S. Pat. Nos. 5,020,194, 5,067,208, 5,088,971, 5,131,121, 5,161,286, 5,301,394, 5,301,395, and 5,442,837 use a slit, notch or other means to accommodate the separator finger in the end position. These means in the fasteners create additional steps in the manufacturing process and thus may increase the cost of these fasteners. 
     A reclosable fastener with a slider and without a separator finger nor the use of a track is described in U.S. Pat. Nos. 3,074,137 and 5,442,838. However, the fastener in the &#39;137 patent would be too expensive to manufacture and may not seal when the slider is in the end position. With respect to the fastener in the &#39;838 patent, the slider does not manipulate the interlocking elements directly. Rather, the slider engages the structure located below the interlocking elements to control the opening and closing of the interlocking elements. Difficulties and additional variables can arise when the slider does not act directly upon the interlocking elements. In addition, the fastener in the &#39;838 patent may not operate properly if the tolerances are incorrect for the slider and/or the fastener. The structure below the interlocking elements and/or the slider may be difficult to extrude or manufacture. If the tolerances are incorrect, the slider may not move smoothly or fail to open or close the fastener elements. Thus, it would be difficult to achieve a properly functioning fastener. 
     Thus, the prior art has failed to afford a closure device with a slider and a separator finger which establishes a leak proof seal without the use of slits, notches or other means. It is a general object of the present invention to provide such a closure device. It is a further general object of the present invention to provide a container that is closeable and sealable by means of such a closure device. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention satisfies these general objects by providing a closure device with interlocking fastening strips and a slider which establishes a leak proof seal. The closure device comprises first and second interlocking fastening strips arranged to be interlocked over a predetermined length and a slider with a separator finger which slidably engages said first and second fastening strips. The first fastening strip includes a first closure element and the second fastening strip includes a second closure element. The slider facilitates the occlusion of the closure elements when moved towards a first end of the fastening strips and deocclusion of the closure elements when moved towards a second end of the fastening strips. The separator finger extends into the closure elements without extending completely through the closure elements. The portion of the closure elements below the separator finger are occluded when the slider is at the first end of the fastening strips. 
    
    
     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 an enlarged partial top view of the container in FIG.  1 . 
     FIG. 3 is an enlarged partial cross-sectional view taken along line  3 — 3  in FIG.  2 . 
     FIG. 4 is a front view of the slider in FIG.  2 . 
     FIG. 5 is a rear view of the slider in FIG.  2 . 
     FIG. 6 is a bottom view of the slider in FIG.  2 . 
     FIG. 7 is a cross-sectional view taken along line  7 — 7  in FIG.  4 . 
     FIG. 4A is a front view of another embodiment of the slider. 
     FIG. 5A is a rear view of the slider in FIG.  4 A. 
     FIG. 6A is a bottom view of the slider in FIG.  4 A. 
     FIG. 7A is a cross-sectional view taken along line  7 A— 7 A in FIG.  4 A. 
     FIG. 8A is a cross-sectional view taken along line  8 A— 8 A in FIG.  4 A. 
     FIG. 8 is an enlarged partial cross-sectional view taken along line  8 — 8  in FIG.  2 . 
     FIG. 9 is an enlarged partial cross-sectional view taken along line  9 — 9  in FIG.  2 . 
     FIG. 10 is an enlarged partial cross-sectional view taken along line  10 — 10  in FIG.  2 . 
     FIG. 11 is an enlarged partial cross-sectional view taken along line  11 — 11  in FIG.  2 . 
     FIG. 12 is an enlarged partial cross-sectional view taken along line  12 — 12  in FIG.  2 . 
     FIG. 13 is an enlarged partial cross-sectional view taken along line  13 — 13  in FIG.  2 . 
     FIG. 14 is an enlarged partial top view of the container shown in FIG. 1 with the slider in the end position and the fastening strips in the occluded position. 
     FIG. 15 is an enlarged cross sectional view taken along line  15 — 15  in FIG.  14 . 
     FIG. 16 is an enlarged cross sectional view taken along line  16 — 16  in FIG.  14 . 
     FIG. 17 is an enlarged cross sectional view taken along line  17 — 17  in FIG.  14 . 
     FIG. 18 is an enlarged cross sectional view taken along line  18 — 18  in FIG.  14 . 
     FIG. 19 is an enlarged cross sectional view taken along line  19 — 19  in FIG.  14 . 
     FIG. 20 is an enlarged cross sectional view taken along line  20 — 20  in FIG.  14 . 
     FIG. 21 is a front view of another embodiment of the closure device according to this invention showing a notch in the fastening strips. 
     FIG. 22 is a partial front view of the closure device in FIG.  21 . 
     FIG. 23 is a cross-sectional view taken along the line  23 — 23  in FIG.  22 . 
     FIG. 24 is a front view of another embodiment of the closure device according to this invention showing a slit in the fastening strips. 
     FIG. 25 is a partial front view of the closure device in FIG.  24 . 
     FIG. 26 is a cross-sectional view taken along the line  26 — 26  in FIG.  25 . 
     FIG. 27 is a cross-sectional view of another embodiment of the closure device according to this invention in a deoccluded position. 
     FIG. 28 is a cross-sectional view of the closure device in FIG. 27 in an occluded position. 
     FIG. 29 is a cross-sectional view of another embodiment of the closure device according to this invention in a deoccluded position. 
     FIG. 30 is a cross-sectional view of the closure device in FIG. 29 in an occluded position. 
     FIG. 31 is a cross-sectional view of another embodiment of the closure device according to this invention in a deoccluded position. 
     FIG. 32 is a cross-sectional view of the closure device in FIG. 31 in the occluded position. 
     FIG. 33 is a cross-sectional view of another embodiment of the closure device according to this invention in a deoccluded position. 
     FIG. 34 is a cross-sectional view of the closure device in FIG. 33 in an occluded position. 
     FIG. 35 is a front view of another embodiment of the container according to the present invention in the form of a plastic bag. 
     FIG. 36 is a partial front view of the slider of FIG. 35 in the end position. 
     FIG. 37 is a top view of FIG. 36 with the slider in the end position and the fastening strips in the occluded position. 
     FIG. 38 is an enlarged cross sectional view taken along line  38 — 38  in FIG.  37 . 
     FIG. 39 is an enlarged cross sectional view taken along line  39 — 39  in FIG.  37 . 
     FIG. 40 is an enlarged cross sectional view taken along line  40 — 40  in FIG.  37 . 
     FIG. 41 is an enlarged cross sectional view taken along line  41 — 41  in FIG.  37 . 
     FIG. 42 is an enlarged cross sectional view taken along line  42 — 42  in FIG.  37 . 
     FIG. 43 is an enlarged cross sectional view taken along line  43 — 43  in FIG.  37 . 
     FIG. 44 illustrates a slider according to the present invention. 
     FIG. 45 illustrates a slider according to the present invention. 
     FIG. 46 illustrates a cross sectional view taken along line  46 — 46  in FIG. 44 of a slider according to the present invention. 
     FIG. 47 illustrates a female fastening strip of a closure device according to the present invention. 
     FIG. 48 illustrates a male fastening strip of a closure device according to the present invention. 
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The present invention provides interlocking closure devices with a slider which establishes a leak proof seal. As used herein and as generally understood in the art, the terms “male” and “female” closure elements refer to closure elements wherein the element that interlocks into the other closure element is referred to as the “male closure element” and the outer element is referred to as the “female closure element”. 
     FIG. 1 illustrates a container according to the present invention in the form of a plastic bag  120  having a sealable closure device  121 . The bag  120  includes side walls  122  joined at seams  125  to form a compartment sealable by means of the closure device  121 . 
     The closure device comprises male and female fastening strips  130 ,  131  and a slider  132 . As shown in FIG. 3, the female fastening strip  131  includes a female closure element  134 . The male fastening strip  130  comprises a male closure element  136  for engaging the female closure element  134 , and further may include a pair of male wings  137  spaced-apart on the male fastening strip on each side of the male closure element  136 . 
     The female closure element  134  may include a base portion  138  and may include a pair of spaced-apart parallely disposed webs  140 ,  141  extending from the base portion  138 . The webs  140 ,  141  may include female hook closure portions  142 ,  144  extending from the webs  140 ,  141  respectively, and facing towards each other. The female hook portions  142 ,  144  may include guide surfaces  146 ,  147  which serve to guide the hook portions  142 ,  144  for occluding with the male hook portions of a mating closure element. 
     The male closure element  136  may include a base portion and may include a pair of spaced-apart, parallely disposed webs  150 ,  151  extending from the base portion  148 . The webs  150 ,  151  may include male hook closure portions  152 ,  154  extending from the webs  150 ,  151  respectively and facing away from each other. The male hook portions  152 ,  154  may include guide surfaces  145 ,  155 , which generally serve to guide the hook portions  152 ,  154  for occlusion with the female hook portions  142 ,  144  of the mating female closure element. The guide surface  145  may also have a rounded crown surface. In addition, the hook portions may be designed so that the hook portions  144 ,  154  adjacent the interior of the container provide a greater resistance to opening of the closure device. The male fastening strip may include wings as shown in FIG.  3 . The male wings  137  are flexible and extend from the base of the fastening strip. Each wing terminates in an end portion  143  which projects outwardly from the wing  137 . The fastening strip may also include a color change enhancement member  156 . 
     Referring to FIGS. 4-7, the slider  132  may include a top portion  170 , a separator finger  172 , a first side portion  174 , a second side portion  176 , a bottom portion  178  and a slot  180 . The separator finger  172  extends downward from the top portion  170  toward the slot  180 . The slider  132  has a first end  184  and a second end  186 .  35  The separator finger  172  extends from the second end  186  towards the first end  184 . The separator finger has a first end  190  and a second end  192  which correspond with the first end  184  and second end  186  of the slider. The first end  190  has a rounded surface  194  and the second end  192  has two corners or edges  196 ,  198 . The separator finger  172  has a first side portion  214  which corresponds to the first side portion  174 , a second side portion  216  which corresponds to the second side portion  176 , and a bottom portion  218  which corresponds with bottom portion  178 . 
     The top portion  170  of the slider has an inner surface  220  and an outer surface  222 . The width  226  of the top portion  170  tapers and becomes smaller beginning at the second end  186  and moving towards the first end  184 . 
     The bottom portion  178  of the slider has an inner surface  230  and an outer surface  232 . The width  234  of the bottom portion  178  tapers and becomes smaller beginning at the second end  186  and moving towards the first end  184 . 
     The first side portion  174  has an inner surface  240  and an outer surface  242 . The first side portion  174  is angled inwardly toward the longitudinal axis  246  of the slider beginning at the second end  186  and moving toward the first end  184 . The second side portion  176  has an inner surface  248  and an outer surface  250 . The second side portion  176  is angled inwardly toward the longitudinal axis  246  of the slider beginning at the second end  186  and moving toward the first end  184 . 
     The bottom portion  178  has a slot  180  which extends from the outer surface  232  to the inner surface  230 . In addition, the slot extends from the first end  184  to the second end  186  of the slider. The slot has substantially the same width from the first end  184  to the second end  186  of the slider. 
     Another embodiment of the slider is shown in FIGS. 4A-7A. This slider is similar to the slider in FIGS. 4-7 except the separator finger has a different shape. Specifically, the slider  132 A has a separator finger  172 A with a triangular shape. The separator finger  172 A has a first end  190 A and a second end  192 A. The first end  190 A has a rounded surface  194 A and the second end  192 A has two corners or edges  196 A,  198 A. The second end  192 A is wider than the first end  190 A. 
     The separator finger  172 A has a first side portion  214 A and a second side portion  216 A. The side portions  214 A,  216 A taper inward beginning at the second end  192 A and moving towards the first end l 90 A as shown in FIGS. 6A and 7A. The separator finger  172 A has a triangular shape as shown in FIG.  6 A. 
     Referring to FIGS. 4A and 5A, the separator finger  172 A has a bottom portion  218 A and a top portion  219 A. The top portion  219 A is wider than the bottom portion  218 A. The first side portion  214 A and the second side portion  216 A taper inward beginning at the top portion  219 A and moving towards the bottom portion  218 A as shown in FIGS.  4 A and SA. The separator finger  172 A has a triangular shape as shown in FIG.  4 A. 
     Referring to FIG. 8A, the second end  192 A of the separator finger has a height  224 A from the top portion  170 A. The first end  190 A has a height which may be less than the height of the second end. The separator finger  172 A decreases in height  224 A along the length of the separator finger from the second end  192 A to first end  190 A. The separator finger  172 A has a triangular shape as shown in FIG.  8 A. 
     In other embodiments, the height, the width, the length and the separation of the sides of the separator finger may be constant or may vary on the separator finger, either individually or in any combination. For example, in one embodiment of the separator finger, the width may be constant but the height decreases. In another embodiment of the separator finger, the height may be constant, but the width decreases. 
     The slider may be a one piece construction or may include several separate pieces which are assembled in several different ways as shown in U.S. Pat. Nos. 5,007,142, 5,283,937, 5,426,830. 
     FIGS. 8-13 illustrate occlusion and deocclusion of the closure device. When FIGS. 8-13 are viewed in numerical sequence, FIGS. 8-13 illustrate occlusion of the fastening strips. When FIGS. 8-13 are viewed in reverse numerical sequence (i.e. viewed from FIG. 13 backwards to FIG.  8 ), FIGS. 13-8 illustrate deocclusion of the fastening strips. 
     The occlusion of the fastening strips will be described and then the deocclusion of the fastening strips will be described. The slider  132  facilitates the occlusion of the fastening strips  130 ,  131  by moving the fastening strips towards each other and causing the closure portions to engage. The closure portions engage in a sequential fashion with the inner closure portions  144 ,  145  engaging first and then the outer closure portions  142 ,  152  engaging second. Referring to FIG. 2, the slider  132  is moved in the occlusion direction  280  and the fastening strips  130 ,  131  enter the slider  132  as shown in FIG.  8 . Referring to FIG. 8, the fastening strips  130 ,  131  are deoccluded and the separator finger  172  is positioned between closure portions  142 ,  152 . The inner surface  240  of the first side portion and the inner surface  248  of the second side portion are separated by a width  260 . 
     As the slider is moved further along the fastening strips in the occlusion direction  280  as shown in FIG. 2, the slider causes the fastening strips to move closer together as shown in FIG.  9 . Referring to FIG. 9, the fastening strips  130 ,  131  are deoccluded and the separator finger  172  is positioned between closure portions  142 ,  152 . However, the inner surface  240  and the inner surface  248  are closer together than in FIG.  8  and are separated by a width  262  which is less than width  260  in FIG.  8 . The inner surfaces  240 ,  248  are beginning to engage the side walls  122  and thus the fastening strips  130 ,  131 . 
     As the slider continues to move along the fastening strips in the occlusion direction  280  as shown in FIG. 2, the slider continues to cause the fastening strips to move closer together as shown in FIG.  10 . Referring to FIG. 10, the fastening strips  130 ,  131  are deoccluded but the separator finger  172  is not between the closure portions  142 ,  152 . The fastening strips are deoccluded because the fastening strips are continuous and the deoccluded portions of the fastening strips in FIGS. 8 and 9 are acting upon the portions of the fastening strips in FIG.  10 . In fact, with respect to FIGS. 8-13, the positions of the fastening strips are effected not only by the forces acting upon them by the slider at that location but are also effected by the position of the fastening strips at locations before and after that location. For example, the positions of the fastening strips in FIG. 9 are effected by the positions of the fastening strips in FIGS. 8 and 10. 
     The amount of effect that the position of fastening strips from one location has upon the position of the fastening strips in another location depends upon several factors, such as, the structure of the fastening strips and the material from which the fastening strips are made. For example, if the base of the fastening strips are relatively thick, then the effect at other locations would be greater than if the base was relatively thin. As another example, if the material for the fastening strips is relatively rigid, then the effect at other locations would be greater than if the material was relatively flexible. 
     Returning to FIG. 10, the inner surface  240  and the inner surface  248  are closer together than in FIG.  9  and are separated by a width  264  which is less than width  262  in FIG.  9 . The inner surfaces  240 ,  248  are engaging the sidewalls  122  and thus the fastening strips  130 ,  131 . The inner surfaces  240 ,  248  are applying forces to the fastening strips which causes the fastening strips to move closer together. The inner closure portions  144 ,  154  are closer to each other than the outer closure portions  142 ,  152  due to the separating action of the separator finger  172  as shown in FIGS. 8 and 9. 
     As the slider continues to move along the fastening strips in the occlusion direction  280  as shown in FIG. 2, the slider continues to cause the fastening strips to move closer together as shown in FIG.  11 . Referring to FIG. 11, the inner closure portions  144 ,  154  have occluded. More specifically, the male hook portion  154  has engaged the female hook closure portion  144 . As the slider applies forces to the fastening strips, the female web  141  deflects outwardly and the male web  151  deflects inwardly in order to allow the female hook portion  144  and the male hook portion  154  to pass each other. In addition, the hook closure portions may also deflect during this process. The guide surfaces  145 ,  147  serve to guide the hook portion  154  for occluding with hook portion  144 . As the slider  132  continues to apply forces, the female hook portion  144  engages the male hook portion  154  as shown in FIG.  11 . Similarly, the outer closure portions  142 ,  152  occlude as the guide surfaces  146 ,  155  and the hook portions  142 ,  152  engage each other as shown in FIGS. 11 and 12. 
     As shown in FIG. 11, the inner surfaces  240 ,  248  are closer together than in FIG.  10  and are separated by a width  266  which is less than width  264  in FIG.  10 . The inner surfaces  240 ,  248  are engaging the sidewalls  122  and thus the fastening strips  130 ,  131 . The inner surfaces  240 ,  248  are applying forces to the fastening strips which causes the fastening strips to move closer together. 
     As the slider continues to move along the fastening strips in the occlusion direction, the slider continues to cause the fastening strips to move closer together as shown in FIG.  12 . Referring to FIG. 12, the fastening strips  130 ,  131  are occluded. Specifically, the inner closure portions  144 ,  154  and the outer closure portions  142 ,  152  are occluded. The guide surfaces  146 ,  155  and the hook portions  142 ,  152  engaged each other as noted above. The inner surfaces  240 ,  248  are closer together in FIG. 12 as compared to FIG.  11  and are separated by a width  268  which is less than width  266  in FIG.  11 . The inner surfaces  240 ,  248  apply forces to the fastening strips which causes the fastening strips to move closer together. 
     As shown in FIG. 13, the fastening strips  130 ,  131  are occluded prior to exiting the slider. The inner surfaces  240 ,  248  are closer together in FIG. 13 as compared to FIG.  12  and the inner surfaces  240 ,  248  are separated by a width  270  which is less than width  268  in FIG.  12 . The inner surfaces  240 ,  248  apply forces to the fastening strips which causes the fastening strips to move closer together. As shown in FIG. 13, the fastening strips  130 ,  131  are moved toward each other so that a space is temporarily created between the hook closure portions  142 ,  144 ,  152 ,  154  to assure that the hook closure portions have fully engaged. After the fastening strips exit the slider, the fastening strips will return to positions relative to each other similar to FIG.  12 . 
     The slider  132  facilitates the deocclusion of the fastening strips  130 ,  131  by moving the fastening strips away from each other and causing the webs to disengage. The webs disengage in a sequential fashion with the outer webs  140 ,  150  disengaging first and then the inner webs  141 ,  151  disengaging second. 
     The deocclusion of the fastening strips  130 ,  131  in FIGS. 8-13 would occur in the reverse order of these figures. Thus, deocclusion is illustrated by beginning at FIG.  13  and moving in reverse order toward FIG.  8 . Referring to FIG. 2, the slider  132  is moved in the deocclusion direction  281  and the fastening strips  130 ,  131  enter the slider  132  as shown in FIG.  13 . Referring to FIG. 13, the fastening strips  130 ,  131  are occluded as they enter the slider  132 . The inner surfaces  240 ,  248  are separated by a width  270 . 
     As the slider continues to move along the fastening strips in the deocclusion direction  281 , the slider causes the fastening strips to move away from each other as shown in FIG.  12 . Referring to FIG. 12, the inner surfaces  240 ,  248  are separated by a width  268  which is greater than the width  270  in FIG.  13 . As noted above, the positions of the fastening strips are effected not only by the forces acting upon them by the slider at that specific location, but are also effected by the position of the fastening strips at locations before and after that specific location. In this case, the fastening strips  130 ,  131  are being urged against the inner surfaces  240 ,  248  due to the separating action of the separating finger  172  as shown in FIGS. 8-9. 
     As the slider continues to move along the fastening strips in the deocclusion direction  281  as shown in FIG. 2, the slider continues to cause the fastening strips to move away from each other as shown in FIG.  11 . Referring to FIG. 11, the inner surfaces  240 ,  248  are separated by a width  266  which is greater than the width  268  in FIG.  12 . The outer closure portions  142 ,  152  have deoccluded. The outer closure portions deocclude due to the separating action of the separating finger  172  as shown in FIGS. 9 and 10 and because the width  266  of the inner surfaces  240 ,  248  allows the fastening strips  130 ,  131  to move further apart and thus permit the outer closure portions  142 ,  152  to deocclude. 
     Referring to FIG. 10, the inner surfaces  240 ,  248  are separated by a width  264  which is greater than the width  266  in FIG.  11 . The inner closure portions have deoccluded. The inner closure portions  144 ,  154  deocclude due to the separating action of the separating finger  172  as shown in FIGS. 9 and 10 and because the width  264  of the inner surfaces  240 ,  248  allows the fastening strips  130 ,  131  to move further apart and thus permit the inner closure portions  144 ,  154  to deocclude. 
     Referring to FIG. 9, the inner surfaces  240 ,  248  are separated by a width  262  which is greater than the width  264  in FIG.  10 . In addition, as shown in FIGS. 2 and 9, the separator finger  172  engages the outer closure portions  142 ,  152  and causes the outer closure portions to separate and move outward towards the inner surfaces  240 ,  248 . The separator finger  172  has a rounded surface  194  which facilitates the engagement between the separator finger  172  and the outer closure portions  142 ,  152 . The fastening strips  130 ,  131  move outwards until the inner surfaces  240 ,  248  resist any further outward movement. 
     As the slider is moved further along the fastening strips, the slider permits further separation or deocclusion of the fastening strips. Referring to FIG. 8, the inner surfaces  240 ,  248  are separated by a width  260  which is greater than the width  262  in FIG.  9 . The fastening strips  130 ,  131  move outwards until the inner surfaces  240 ,  248  would resist any further outward movement. As shown in FIGS. 2 and 8, the inner closure portions  144 ,  154  and the outer closure portions  142 ,  152  of the fastening strips  130 ,  131  are deoccluded when the fastening strips exit the slider  132 . 
     In summary, the invention provides two fastening strips and a slider with a separator finger wherein the separator finger extends into the closure elements without extending completely through the closure elements. More specifically, the first closure element includes a first closure portion and a second closure portion and the second closure element includes a third closure portion and a fourth closure portion. The first closure portion engages the third closure portion and the second closure portion engages the fourth closure portion. The separator finger extends between the first and third closure portions but not between the second and fourth closure portions. 
     FIG. 14 shows the slider  132  in the end position of the fastening strips  130 ,  131  near the seam  125 . FIGS.  15 - 20  illustrate occlusion of the fastening strips in the end position. In accordance with one feature of the invention, 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 finger extends between the outer closure portions. 
     Referring to FIGS. 15-20, the occlusion and deocclusion of the outer closure portions  142 ,  152  is substantially similar to the occlusion and deocclusion of the outer closure portions in FIGS. 8-13. Furthermore, the movement of the inner closure portions  144 ,  154  in FIGS. 18-20 would be substantially the same as the movement of the inner closure portions  144 ,  154  in FIGS. 11-13. 
     However, the movement of the inner closure portions  144 ,  154  in FIGS. 15-17 is different than the movement of the inner closure portions  144 ,  154  in FIGS. 8-10. As noted above, the positions of the fastening strips are effected not only by the forces acting upon them by the slider at that location but are also effected by the position of the fastening strips at locations before and after that location. Specifically, with respect to the position of the inner closure portions  144 ,  154  in FIGS. 15-17, the position of the inner closure portions  144 ,  154  is effected by the seam  125  at the end of the fastening strips. At the seam  125 , the fastening strips  130 ,  131  are melted together which effectively occludes the fastening strips. This occlusion of the fastening strips  130 ,  131  at the seam  125  prevents separating action of the separator finger  172  from deoccluding the inner closure portions  144 ,  154 . Thus, the inner closure portions  144 ,  154  remain occluded even though the separator finger  172  is attempting to deocclude the inner closure portions. Consequently, the inner closure portions  144 ,  154  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. 
     For example, as the user moves the slider  132  in the occlusion direction  280  as shown in FIG. 14, the slider would occlude the fastening strips  130 ,  131  in the sequence shown in FIGS. 15-20. When the slider is in the locations shown in FIGS. 15-17, the inner closure portions  144 ,  154  of the fastening strips would usually be deoccluded as shown in FIGS. 8-10. In addition, the slider is prevented from further movement in the occlusion direction  280  when the separator finger  172  contacts the seam  125  as shown in FIG.  14 . However, as noted above, the seam  125  causes the inner closure portions  144 ,  154  to be occluded at the locations in FIGS. 15-17 even when the slider is not present. Therefore, when the slider moves to the locations shown in FIGS. 15-17, the inner closure portions  144 ,  154  are already occluded and the separating action of the separating finger  172  is not able to overcome the occlusion effect of the seam  125 . Thus, the inner closure portions  144 ,  154  remain occluded through the length of the fastening strips and establish a leak proof seal. 
     Another feature of the invention is that the slider may also provide an additional seal. Referring to FIGS. 4-6 and  15 - 20 , the slider  132  includes a slot  180  at the bottom of the slider and which extends along the length of the slider. As shown in FIG. 15 the sidewalls  122  of the bag extend from the fastening strips  130 ,  131  and downward through the slot  180 . The slot  180  includes a first face  286  and a second face  288  which are separated by a width  284 . The width  284  is small enough to cause a seal between the sidewalls  122  near the location of the faces  286 ,  288  and large enough to allow the slider to move along the sidewalls  122  without making the slider too difficult to move. Thus, the slot  180  provides an additional seal along the length of the slider. 
     The fastening strips may also achieve a position at any angle to the vertical when the fastening strips are within the slider. Specifically, referring to FIG. 9, the fastening strips  130 ,  131  are at angles  290 ,  292  to the vertical plane. The fastening strips are at an angle for several reasons. First, the separator finger  172  is acting upon the outer closure portions  142 ,  152  to separate the closure portions. Second, the slot  180  is acting upon the sidewalls  122  and pulling the sidewalls  122  and the fastening strips  130 ,  131  toward the slot  180 . Third, the occlusion of the inner closure portions  144 ,  154  at the location in FIG. 11 is effecting the position of the fastening strips  130 ,  131  at the locations in FIGS. 8,  9  and  10 . Thus, the fastening strips  130 ,  131  are at an angle to the vertical. In another embodiment, the inner surfaces  240 ,  248  could be positioned on an angle to substantially match the angle of the fastening strips at various locations within the slider. 
     The slider is attached to the fastening strips so that the slider may move in the longitudinal X axis but not in the transverse Y axis and not in the vertical Z axis. Specifically, the slot  180  and the bottom portion  178  form shoulders which assist in retaining the slider  132  on the fastening strips  130 ,  131 . Referring to FIG. 15, the inner surfaces  220 ,  230 ,  240 ,  248  enclose the fastening strips  130 ,  131 . Furthermore, the width  284  of the slot  180  does not permit the passage of the fastening strips  130 ,  131 . Therefore, a user should not be able to remove the slider  132  from the fastening strips  130 ,  131  by pulling in an upward direction with respect to FIG.  15 . In addition, the sidewalls  122  and/or the fastening strips  130 ,  131  engage the inner surfaces  220 ,  230 ,  240 ,  248  and act as guides for the sliding movement of the slider  132  along the fastening strips. 
     Another feature of the invention is that the slider may be used without an additional end stop on the fastening strips. As noted above and as shown in FIG. 14, the slider is prevented from further movement in the occlusion direction  280  when the separator finger  172  contacts the seam. Therefore, the slider may be used without an additional end stop on the end of the fastening strips. However, the slider may be used with additional end stops, such as, the end stops shown in U.S. Pat. Nos. 5,067,208, 5,088,971, 5,131,121, 5,161,286, 5,189,764, 5,405,478, 5,442,837, 5,448,807, 5,482,375, which are incorporated herein by reference. 
     The fastening strips and/or the slider may also include a structure to provide a home or parking position for the slider at the end of the fastening strips, such as, the structure shown in U.S. Pat. Nos. 5,067,208, 5,189,764, 5,301,394 and 5,301,395 which are incorporated herein by reference. 
     The fastening strips and/or the sidewalls of the bag may also include flanges to allow the user to open the bag more easily and insert items in the bag. The flanges would extend above the webs and/or wings and the slider would be increased in height to accommodate the flanges. 
     The fastening strips and the slider may also include a structure to accommodate the separator finger at the end of the fastening strips, such as, the slits, notches and other means as shown in U.S. Pat. Nos. 5,020,194, 5,067,208, 5,088,971, 5,131,121, 5,161,286, 5,301,394, 5,301,395 and 5,442,837, which are incorporated herein by reference. The structure may accommodate the separator finger and thus allow the outer closure portions  142 ,  152  to occlude near the end of the fastening strips. 
     For example, FIGS. 21-23 illustrate another embodiment wherein the fastening strips have a notch near the seam. Referring to FIG. 21, the bag  320  has a closure device  321 . In addition, the bag  320  includes side walls  322  joined at seams  325  to form a compartment sealable by means of the closure device  321 . Referring to FIGS. 21-23, the closure device  321  includes first and second fastening strips  330 ,  331  and a slider  332 . The fastening strips have a notch  378  near the seam  325 . As shown by dashed lines, the notch removes a portion  382  of the fastening strips  330 ,  331  to accommodate the separator finger  372 . The notch  378  permits the closure portions  344 ,  354  and thus, the fastening strips to occlude in the end position. 
     As another example, FIGS. 24-26 illustrate another embodiment wherein the fastening strips have a slit near the seam. Referring to FIG. 24, the bag  420  has a closure device  421 . In addition, the bag  420  includes side walls  422  joined at seams  425  to form a compartment sealable by means of the closure device  421 . Referring to FIGS. 24-26, the closure device  421  includes first and second fastening strips  430 ,  431  and a slider  432 . The fastening strips have a slit  477  near the seam  425 . As shown in FIG. 26, the slit  477  allows the fastening strips  430 ,  431  to accommodate the separator finger  472 . The slit  477  permits the closure portions  444 ,  454  and thus, the fastening strips to occlude in the end position. 
     FIGS. 27 and 28 illustrate another embodiment of the closure device of the present invention. Referring to FIGS. 27-28, the fastening strips  530 ,  531  are similar to fastening strips  130 ,  131  except the fastening strips  530 ,  531  do not include the wings  137  and the color change enhancement member  156 . The remaining components of the fastening strips  530 ,  531 , such as the webs  540 ,  541 ,  550 ,  551  and the closure portions  540 ,  544 ,  552 ,  554  are similar to the components in fastening strips  130 ,  131 . FIG. 27 shows the fastening strips  530 ,  531  in a deoccluded position and FIG. 28 shows the fastening strips  530 ,  531  in a occluded position. The occlusion and deocclusion of the fastening strips  530 ,  531  is similar to the occlusion and deocclusion of the fastening strips  130 ,  131  noted above. 
     FIGS. 29 and 30 illustrate another embodiment of the closure device of the present invention. In this embodiment, the closure device includes another type of closure elements. Referring to FIG. 29, the fastening strip  630  includes a closure element  636  with closure portion  654  similar to the closure portion  154  in FIG.  3 . The fastening strip  631  includes a closure element  634  with a closure portion  644  similar to closure portion  144  in FIG.  3 . The fastening strip  630  also includes a closure portion  652  which is different from closure portion  152  in FIG.  3 . Similarly, the fastening strip  631  also includes a closure portion  642  which is different from closure portion  142  in FIG.  3 . The closure portions  642 ,  652  are known and described in U.S. Pat. Nos. 3,198,228 (which was reissued as Pat. Nos. Re. 28,969), 4,736,496 and 5,363,540 which are incorporated herein by reference. These closure portions are sometimes referred to as “arrowhead” closure portions. The remaining components of the fastening strips  630 ,  631  are similar to the components in fastening strips  130 ,  131 . 
     FIG. 29 shows the fastening strips  630 ,  631  in a deoccluded position and FIG. 30 shows the fastening strips  630 ,  631  in an occluded position. The occlusion and deocclusion of the fastening strips  630 ,  631  is similar to the occlusion and deocclusion of the fastening strips  130 ,  131  noted above. 
     FIGS. 31 and 32 illustrate another embodiment of the closure device of the present invention. In this embodiment, the closure elements include inner arrowhead closure portions. Referring to FIG. 31, the fastening strip  730  includes a closure element  736  with closure portion  752  similar to the closure portion  152  in FIG.  3  and the fastening strip  731  includes closure element  734  with a closure portion  742  similar to closure portion  142  in FIG.  3 . The closure element  736  also includes a closure portion  754  similar to closure portion  652  in FIG.  29 . Similarly, the closure element  734  also includes a closure portion  744  similar to closure portion  642  in FIG.  29 . 
     FIG. 31 shows the fastening strips  730 ,  731  in a deoccluded position and FIG. 32 shows the fastening strips  730 ,  731  in an occluded position. The occlusion and deocclusion of the fastening strips  730 ,  731  is similar to the occlusion and deocclusion of the fastening strips  130 ,  131  noted above. 
     FIGS. 33 and 34 illustrate another embodiment of the closure device of the present invention. In this embodiment, the closure elements include inner and outer arrowhead closure portions. Referring to FIG. 33, the fastening strip  830  includes closure element  836  with an outer closure portion  852  similar to the outer closure portion  652  in FIG.  29  and the fastening strip  831  includes closure element  834  with an outer closure portion  842  similar to outer closure portion  642  in FIG.  29 . The closure element  836  also includes a closure portion  854  similar to closure portion  754  in FIG.  31 . Similarly, the closure element  834  also includes a closure portion  844  similar to closure portion  744  in FIG.  31 . 
     FIG. 33 shows the fastening strips  830 ,  831  in a deoccluded position and FIG. 34 shows the fastening strips  830 ,  831  in an occluded position. The occlusion and deocclusion of the fastening strips  830 ,  831  is similar to the occlusion and deocclusion of the fastening strips  130 ,  131  noted above. 
     Another feature of this invention is to provide an additional seal near the seam for further sealing of the closure elements. Referring to FIGS. 35-38, the bag  620  includes a closure device  921  and sidewalls  922  joined at seams  925 . The closure device  921  includes fastening strips  930 ,  931  and a slider  932 . The sidewalls  922  and the fastening strips  930 ,  931  include an additional seal  934 ,  936  near the seams  925 . 
     The fastening strips  930 ,  931  and the slider  932  are the same as the fastening strips  130 ,  131  and the slider  132  noted above except for the seal  934 ,  936 . In addition, the fastening strips  930 ,  931  occlude and deocclude in the same way as fastening strips  130 ,  131  except when the fastening strips  930 ,  931  encounter the seal  934 ,  936 . 
     The additional seal  934 ,  936  is formed by permanently attaching a portion of the fastening strips  930 ,  931  which are below the separator finger  972 . The seal  934 ,  936  may be formed by heat sealing the fastening strips  930 ,  931  so that the closure portions  944 ,  954  and the inner webs  941 ,  951  are melted together as shown by comparing FIGS. 38-40 with FIGS. 41-43. Referring to FIGS. 35 and 36, the seal  934 ,  936  extends along the fastening strips and slightly beyond the length of the separator finger  972 . However, in other embodiments the seal  934 ,  936  may be less than or equal to the length of the separator finger  972 . 
     The fastening strips  930 ,  931  are shown with two seals  934 ,  936 . However, only one seal is necessary. If only one seal is used, then the seal should be located near the seam where the slider will be positioned when the fastening strips are occluded throughout their length (i.e. seal  934 ). The other seal  936  can be eliminated or can be extended upwards at area  937  (see FIG. 35) to attach the outer webs  940 ,  950  and the closure portions  942 ,  952 . For example, by extending the seal  936  upwards, the separator finger would contact the seal  936  and prevent the slider from further movement sooner than if the slider contacted the seam  925 . The additional seal at area  937  could prevent a portion of the slider from extending over the seam  925 . 
     Referring to FIG. 37, the slider  932  is shown in the end position of the fastening strips  930 ,  931  near the seam  925 . FIGS. 38-43 illustrate occlusion of the fastening strips  930 ,  931  in the end position using the seal  934 . In accordance with the one feature of the invention, these figures demonstrate that the closure device will have a leak proof seal when the slider is in the end position using an additional seal. The leak proof seal is created even though the separator finger extends between the outer webs because the inner webs are occluded or permanently attached at the portion below the separator finger. 
     Referring to FIGS. 38-43, the occlusion and deocclusion of the outer closure portions  942 ,  952  is substantially similar to the occlusion of the outer closure portions  142 ,  152  in FIGS. 15-20. Furthermore, the movement of inner closure portions  944 ,  954  in FIGS. 41-43 is substantially the same as the movement of the inner closure portions  144 ,  154  in FIGS. 18-20. 
     However, as shown in FIGS. 38-40 a portion of the area below the separator finger  972  is permanently attached by the seal  934 . More specifically, the inner closure portions  944 ,  954  are melted together so the closure portions  944 ,  954  do not exist in their previous form. The seal  934  prevents the separating action of the separator finger  972  from deoccluding the seal  934  below the separator finger. Thus, the portion below the separator finger is sealed and the inner closure portions  944 ,  954  remain occluded through the length of the fastening strips to establish a leak proof seal. This leak proof seal is an improvement over the leak proof seal shown in FIGS. 15-20. 
     FIGS. 44-46 illustrate one embodiment of a slider of the present invention. The representative dimensions of the various parameters are given as follows: 
     
       
         
           
               
               
               
             
               
                   
               
               
                 PARAMETER 
                 RANGE (mils) 
                 PREFERRED (mils) 
               
               
                   
               
             
            
               
                 1050 
                 0.260-0.460 
                 0.360 
               
               
                 1052 
                 0.200-0.400 
                 0.300 
               
               
                 1054 
                 0.040-0.150 
                 0.080 
               
               
                 1056 
                 0.075-0.125 
                 0.100 
               
               
                 1058 
                 0.020-0.100 
                 0.063 
               
               
                 1060 
                 0.040-0.150 
                 0.080 
               
               
                 1062 
                 0.140-0.340 
                 0.240 
               
               
                 1064 
                 0.040-0.150 
                 0.08 
               
               
                 1066 
                 0.004-0.024 
                 0.014 
               
               
                 1068 
                 0.250-0.650 
                 0.450 
               
               
                 1070 
                 0.100-0.250 
                 0.175 
               
               
                 1072 
                 0.020-0.080 
                 0.050 
               
               
                 1074 
                 0.002-0.050 Radius 
                 0.005 Radius 
               
               
                   
               
            
           
         
       
     
     The slider may be manufactured by injection molding. The slider may be formed from thermoplastic materials such as, polypropylene, polyethylene, polyamide, polysulfone, ABS, PMMA, HDPE and Nylon. 
     FIGS. 47 and 48 illustrate the female and male fastening strips respectively of one embodiment of the closure device of the present invention. The representative dimensions of the various parameters are given as follows: 
     
       
         
           
               
               
               
             
               
                   
               
               
                 PARAMETER 
                 RANGE (inches) 
                 PREFERRED (inches) 
               
               
                   
               
             
            
               
                 1171 
                 0.025-0.105 
                 0.065 
               
               
                 1172 
                 0.010-0.016 
                 0.013 
               
               
                 1173 
                 0.015-0.055 
                 0.035 
               
               
                 1174 
                 0.019-0.059 
                 0.039 
               
               
                 1175 
                  0.80-0.160 
                 0.120 
               
               
                 1176 
                 0.010-0.016 
                 0.013 
               
               
                 1177 
                 0.030-0.090 
                 0.055 
               
               
                 1178 
                  0.03-0.090 
                 0.055 
               
               
                 1181 
                 0.140-0.220 
                 0.180 
               
               
                 1182 
                 0.020-0.070 
                 0.045 
               
               
                 1183 
                 0.013-0.033 
                 0.023 
               
               
                 1184 
                 0.015-0.065 
                 0.040 
               
               
                 1185 
                  0.85-0.165 
                 0.125 
               
               
                 1186 
                 0.032-0.062 
                 0.047 
               
               
                 1187 
                 0.010-0.016 
                 0.013 
               
               
                 1188 
                 0.033-0.063 
                 0.047 
               
               
                 1189 
                 0.010-0.016 
                 0.013 
               
               
                 1190 
                 0.010-0.016 
                 0.013 
               
               
                   
               
            
           
         
       
     
     The fastening strips may be manufactured by extrusion through a die that has the approximate dimensions given above, although the die should be made somewhat larger than the desired final dimensions of the fastening strip, inasmuch as shrinkage of the extruded fastening strip is likely upon cooling. The fastening strips of the closure device should be manufactured to have approximately uniform cross-sections. This not only simplifies the manufacturing of a device, but also contributes to the physical flexibility of the device, which is a desirable property in any event. 
     Generally, the closure elements of this invention may be formed from thermoplastic materials such as, 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 novel fastener of this invention. Preferably, the closure element is made from low density polyethylene. The selection of the thermoplastic material will be related to the closure design and its Young&#39;s Modulus and desired elasticity and flexibility correlated to provide the functionality of the closure as herein claimed. 
     When the fastener of the present invention is used in a sealable bag, the fastener and the films that form the body of the bag can be made from heat sealable material. The bag thus can be formed economically by heat sealing the aforementioned components to form the bag using thermoplastics of a type aforementioned for formation of the closure elements. Preferably, the bag is made from a mixture of high pressure, low density polyethylene and linear low density polyethylene. 
     The closure elements of the invention may be manufactured by extrusion or other known methods. The closure device can be manufactured as individual fastening strips for later attachment to a film, or the fastening strips can be manufactured integrally with a film. In addition, the closure elements can be manufactured with or without flange portions on one or both of the closure elements depending upon the intended use or expected additional manufacturing operations. 
     Generally, the closure device of this invention can be manufactured in a variety of forms to suit the intended use. In the practice of the instant invention, the closure device may be integrally formed with the sidewalls of a container, or connected to a container, by the use of any of many known methods. For example, a thermoelectric device can be applied to a film in contact with a flange portion of a closure element or the thermoelectric device can be applied to a film in contact with the base portion of a closure element 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 closure element. The thermoelectric device can be heated rotary discs, traveling heater bands, resistance-heated slide wires, or the like. The connection between the film and the closure element can 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 closure element to the film stock may be carried out either before or after the film is U-folded to form a bag. In any event, such bonding is done prior to side sealing the bags at the edges by conventional thermal cutting. In addition, the male and female closure elements can be positioned on opposite sides of a film. Such an embodiment would be suited for wrapping an object or a collection of objects such as wires. The male and female closure elements on a film generally should be parallel to each other, but this will depend on the intended use. 
     Thus, the present invention provides a closure device that overcomes the drawbacks inherent in the prior art. Specifically, the present invention affords a closure device with interlocking fastening strips and a slider which establishes a leak proof seal. 
     While particular embodiments of the invention have been shown, it will of course be understood that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the foregoing teachings. It is, therefore, contemplated by the appended claims to cover any such modifications as incorporate those features which constitute the essential features of these improvements within the true spirit and scope of the invention. All references and copending applications cited herein are hereby incorporated by reference in their entireties.