This invention generally relates to slider-operated zippers for use in reclosable packaging, such as bags or pouches. In particular, the invention relates to zippers having slider end stops.
Reclosable bags are finding ever-growing acceptance as primary packaging, particularly as packaging for foodstuffs such as cereal, fresh vegetables, snacks and the like. Such bags provide the consumer with the ability to readily store in a closed, if not sealed, package any unused portion of the packaged product even after the package is initially opened. To gain acceptance as a primary package for foodstuffs, it is virtually mandatory that the package exhibit some form of tamper evidence to protect the consumer and maintain the wholesomeness of the contained product. In addition, in many cases it is necessary that food product be hermetically packaged.
Reclosable fastener assemblies are useful for sealing thermoplastic pouches or bags. Such fastener assemblies typically include a plastic zipper and a plastic slider. Typically, the plastic zippers include a pair of interlockable profiled members that form a closure. As the slider moves across the profiles, the profiles are opened or closed. The profiles in plastic zippers can take on various configurations, e.g. interlocking rib and groove elements having so-called male and female profiles, interlocking alternating hook-shaped closure members, etc. Reclosable bags having slider-operated zippers are generally more desirable to consumers than bags having zippers without sliders because the slider eliminates the need for the consumer to align the interlockable zipper profiles before causing those profiles to engage.
In one type of slider-operated zipper assembly, the slider straddles the zipper and has a separating finger at one end that is inserted between the profiles to force them apart as the slider is moved along the zipper in an opening direction. The other end of the slider is sufficiently narrow to force the profiles into engagement and close the zipper when the slider is moved along the zipper in a closing direction. Other types of slider-operated zipper assemblies avoid the use of a separating finger. For example, U.S. Pat. No. 6,047,450 discloses a zipper comprising a pair of mutually interlockable profiled closure members, portions of which form a fulcrum about which the profiled closure members may be pivoted out of engagement when lower edges of the bases are forced towards each other.
One of the important features of such reclosable fastener assemblies are the end stops, which prevent the slider from falling off the end of the fastener. End stops have taken on various configurations, such as, for example, riveted end clamps such as those described in U.S. Pat. Nos. 5,067,208 and 5,161,286; transverse end stops made from molten material of the fastener strips, as described in U.S. Pat. No. 5,088,971; reciprocating anvils, as described in U.S. Pat. No. 5,131,121; tubular end stops, as described in U.S. Pat. No. 5,405,478; a window structure (i.e., a recess) combined with sealed zipper ends, as described in U.S. Pat. No. 5,442,837; or plastic end clips fused to the zipper as described in U.S. Pat. No. 5,448,807. In U.S. Pat. No. 5,442,837, the recesses in the zipper flanges form a window for receiving a horizontal portion of a separator structure that depends from the top wall of the slider.
U.S. Pat. No. 5,950,285 discloses a reclosable bag having end stops that prevent a slider from moving beyond the end of the zipper when the slider reaches either the closed or fully open position. The end stops are formed from the material of the zipper profiles and “rise vertically” from the zipper to block and prevent further longitudinal movement of the slider. The end stops are formed by first aligning together the opposing profiles at an end stop area proximate to an end of the bag, and then fusing the zipper profiles at the end stop area to provide a vertical structure for preventing movement of the slider past the ends of the zipper, while at the same time keeping the so-called “rails,” i.e., the corners of the zipper profile that retain the slider, intact.
A vertical end stop may fold or bend when a slider is pressed against the end stop. If the end stop folds or bends, the slider may not be stopped, thereby rendering the end stop ineffective. There is a need for alternative slider end stop designs.
The invention is directed in part to a slider-operated zipper having recessed slider end stops. The recesses can be formed in top portions of the profiled closure members or in outwardly facing side portions of one or both profiled closure members. Alternatively, the openings of throughholes that pass through the profiled closure members can serve as end stop recesses. The invention is also directed to a slider having one or more projections or ridges designed to impinge on a wall of a respective recess or throughhole opening in the zipper, thereby stopping the slider, provided that the pull off resistance is not overcome.
One aspect of the invention is a slider-zipper assembly comprising a zipper and a slider mounted to the zipper, wherein the zipper comprises first and second interlockable profiled closure members joined along respective sections proximal to respective ends of the zipper, and a recess proximal to one end of the zipper and defined in part by a stopping surface generally facing toward the other end of the zipper. The slider is movable between first and second slider park positions for engaging or disengaging confronting portions of the first and second closure members and comprises a projection arranged to impinge on the stopping surface. The stopping surface poses an obstacle to further travel of the slider in one direction during impingement of the projection on the stopping surface. The projection is disposed outside the zipper when the slider is located in the middle of the zipper.
Another aspect of the invention is a slider-zipper assembly comprising a zipper and a slider mounted to the zipper, wherein the zipper comprises first and second interlockable profiled closure members joined along respective sections proximal to respective ends of the zipper, a first recess proximal to one end of the zipper and defined in part by a first stopping surface generally facing toward the other end of the zipper, and a second recess proximal to the other end of the zipper and defined in part by a second stopping surface generally facing toward the one end of the zipper. The slider is movable between first and second slider park positions for engaging or disengaging confronting portions of the first and second closure members, a first portion of the slider being in contact with the first stopping surface in the first slider park position and a second portion of the slider being in contact with the second stopping surface in the second slider park position. The first and second portions of the slider are disposed outside the zipper when the slider is located in the middle of the zipper.
A further aspect of the invention is a slider-zipper assembly comprising a zipper and a slider mounted to the zipper, wherein the zipper comprises first and second interlockable profiled closure members joined along respective sections proximal to respective ends of the zipper, a first throughhole proximal to one end of the zipper and a second throughhole proximal to the other end of the zipper. Each of the first and second throughholes passes through the first and second profiled closure members. The slider is movable between first and second slider park positions for engaging or disengaging confronting portions of the first and second closure members, a first portion of the slider being inserted in one end of the first throughhole in the first slider park position and a second portion of the slider being inserted in one end of the second throughhole in the second slider park position.
Another aspect of the invention is a reclosable package comprising: a receptacle having a mouth; and a slider-zipper assembly joined to the receptacle in a manner such that the mouth is closed when the profiled closure members are interlocked with each other and the mouth is open when the profiled closure members are disengaged from each other, the slider-zipper assembly being as described in any of the preceding three paragraphs.
Yet another aspect of the invention is a slider for opening and closing a plastic zipper, comprising: first and second sidewalls; a first cantilevered arm having one end connected to the first side wall and extending forward of the first side wall; a second cantilevered arm having one end connected to the second side wall and extending forward of the second side wall; a third cantilevered arm having one end connected to the first side wall and extending rearward of the first side wall; and a fourth cantilevered arm having one end connected to the second side wall and extending rearward of the second side wall. The first and second cantilevered arms are opposed to each other and can be flexed toward and away from each other. Likewise the third and fourth cantilevered arms are opposed to each other and can be flexed toward and away from each other.
Another aspect of the invention is a slider for opening and closing a plastic zipper, comprising: an opening end comprising a top portion, first and second side portions respectively connected to opposing ends of the top portion of the opening end; a closing end comprising a top portion, and first and second side portions respectively connected to opposing ends of the top portion of the closing end, the closing end being separated from the opening end by a central zone; and a ridge integrally connected to the one of the first and second side portions of one of the opening and closing ends and projecting inward. The ridge comprises an end face and a tapered body having a dimension that decreases as the distance from the end face increases. The tapered body extends from the end face toward the other of the opening and closing ends.
Another aspect of the invention is a slider for opening and closing a plastic zipper, comprising: an opening end comprising a top portion, first and second side portions respectively connected to opposing ends of the top portion of the opening end; a closing end comprising a top portion, and first and second side portions respectively connected to opposing ends of the top portion of the closing end, the closing end being separated from the opening end by a central zone; and first and second ridges respectively integrally connected to the first and second side portions of the opening end and projecting toward each other; and third and fourth ridges respectively integrally connected to the first and second side portions of the closing end and projecting toward each other. The first ridge comprises a first end face and a first tapered body having a dimension that decreases as the distance from the first end face increases, and the second ridge comprises a second end face and a second tapered body having a dimension that decreases as the distance from the second end face increases, the first and second tapered bodies extending from the first and second end faces respectively toward the closing end. The third ridge comprises a third end face and a third tapered body having a dimension that decreases as the distance from the third end face increases, and the fourth ridge comprises a fourth end face and a fourth tapered body having a dimension that decreases as the distance from the fourth end face increases, the third and fourth tapered bodies extending from the third and fourth end faces respectively toward the opening end.
Other aspects of the invention are disclosed and claimed below.
The first embodiment of the invention, a reclosable bag comprising a slider-zipper assembly of the fulcrum type, will be described with reference to
As best seen in
The zipper 10 comprises a closure member 2 having a female profile and a closure member 4 having a male profile that interlocks with the female profile in the zipper section being closed as the slider travels in the closing direction. The zipper 10 further comprises a zipper flange 6 having one end connected or joined to closure member 2 and a zipper flange 8 having one end connected or joined to closure member 4.
The zipper flange 6 is typically secured to one bag wall by a permanent seal proximal to the top of the bag, while zipper flange 8 is secured to the other bag wall by a permanent seal. It should be appreciated that each permanent seal is a band of joined, e.g., fused, material that extends from one side seal of the bag to the other side seal, thereby securing the zipper to the bag along the width of the bag. These permanent seals are generally parallel to each other and may be formed by any conventional method, such as conduction heat sealing.
As illustrated in
When the distal edges of the closure members 2 and 4 are forced towards each other by the side walls of the slider 12, the resulting leverage causes the closure members to pivot oppositely about the fulcrum 11 and disengage from each other, as shown in
The slider 12 can be top-loaded onto the zipper 10 without having to disengage the profiled closure members at the loading point since the slider does not make use of a separating finger. The slider is slidable along the zipper in either a closing direction or an opening direction opposite to the closing direction. The profiled closure members 2 and 4 are fully engaged, i.e., interlocked, with each other as the slider travels in the closing direction. The profiled closure members 2 and 4 are disengaged from each other as the slider travels in the opening direction. The slider 12 is preferably made of a resilient plastic material, such as delrin, polypropylene, PBT, etc.
As shown in
In accordance with the embodiment of the invention shown in
Any geometry can be utilized so long as each recess has a slider stopping surface, against which some portion of the slider can impinge. Each stopping surface generally faces toward the other end of the zipper. The stopping surfaces for recesses 16 and 18, shown in
The stopping surfaces 17 and 19 of recesses 16 and 18 form a slider end stop at one end of the zipper, stopping the slider at a first park position. It should be appreciated that the other end of the zipper will be similarly constructed to stop the slider at a second park position. Thus the slider is movable only along the path between the first and second park positions located at opposite ends of the zipper. In one slider park position, the zipper is fully open; in the other slider park position, the zipper is fully closed.
The stopping surfaces work in conjunction with contacting surfaces of projections or ridges formed on the slider. The slider has one projection or ridge for each stopping surface formed in the zipper. In the embodiment depicted in
Three exemplary ridges with different geometries are shown in
As seen in
In cases where the ridges or projections that cooperate in stopping the slider are supported by the slider sidewalls, the latter are designed with a degree of elasticity. The elasticity of the slider sidewalls must be sufficient to allow the ridges or projections to ride along the external surface of the zipper when the slider is disposed in the middle of the zipper, and then flex inward when the ridge or projection ceases to bear against the zipper profile and overlies a recess formed with a stopping surface in the zipper. Thus, the portions of the slider sidewalls that carry the opposing ridges or projections should be elastically flexible toward and away from each other, i.e., in a lateral direction perpendicular to the longitudinal axis of the zipper. In an ideal design, the overall profile of the zipper is substantially constant along its length except where the recesses with stopping surfaces are formed, e.g., by cutting. Thus, the ridges or projections on both sides and at both ends of the slider will bear against the external surfaces of the zipper profile when in the parked position and the adjoining supporting portions of the sidewall will be flexed apart by the intervening zipper profile whenever the slider is located between the park positions at opposing ends of the zipper and not yet engaged in the recesses. When the ridges or projections on one end of the slider engage the recess, the tip of each ridge or projection will be inserted into the corresponding recess to an increasing depth as the slider continues to move toward the final park position. The tapered body of the ridge or projection will slide against the lip of the recess opposite the stopping surface until the end face of the ridge or projection meets or impinges on the stopping surface, while the supporting portion of the slider sidewall flexes inwardly. As long as the minimum pull-off force is not reached, the impingement of the end faces of the ridges or projections on the stopping surfaces of the recesses in the zipper will stop the slider from further progress toward the end of the zipper. Conversely, when the slider is moved toward the middle of the zipper and away from the park position, the tapered bodies of the engaged ridges or projections will be cammed outward by the lips of the recesses, thereby flexing the supporting portions of the slider laterally outward in opposite directions. The ridges or projections bear against the exterior of the zipper as the slider moves in the opening or closing directions.
As best seen in
A third embodiment of the invention is depicted in
Although
Yet another embodiment of the invention is depicted in
Each end section of the zipper 10 is provided with slider end stops on opposing sides of the zipper. Each slider end stop comprises a stopping surface that forms part of a recess or a throughhole. In
The arms 42, 44, 46 and 48 are designed to be elastically flexible in a direction transverse to the longitudinal axis of the zipper. In other words, the arms 42 and 44 flex so that the pegs at their ends move toward or away from each other. The same is true of arms 46 and 48. As seen in
As seen in
While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for members thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation to the teachings of the invention without departing from the essential scope thereof. Therefore it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
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Number | Date | Country | |
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20040062457 A1 | Apr 2004 | US |