Abstract:
A continuous, progressive, flexible closure formed with rows of opposed keys whose engagement and disengagement is normal to the plane of closure. The closure may include a plurality of first keys, a plurality of second keys, and a slider configured to engage and disengage opposed keys, e.g., by joining and separating protrusions on one set of keys with openings on the second set of keys. Engagement of opposed pairs may be independent of engagement of neighboring pairs, which may increase useful life of the closure. Additionally, first and second keys may have variable relative geometries which, when considered with alignment of skirts in the plane of closure, may allow closure to follow a bend or curve without generally changing the peripheral distance of the opposed rows.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention is directed to a closure device 
         [0003]    2. Description of the Related Art 
         [0004]    Zipper closures are widespread, used to join edges of myriad objects, including luggage, clothing, pockets, pouches, etc. Zippers perform interdigitalization of teeth, hooks, or coils that are arranged in opposition and are engaged or disengaged by means of a slider that draws them into contact or forces them apart. One hallmark of zippers is that this engagement or disengagement occurs via lateral movement in the plane of closure. In other words, the engaged teeth, hooks, or coils depend one upon the other laterally, along the entire length of the closure, from a fixed stop to the slider. 
         [0005]    This lateral interdependence is a frequent cause of zipper failure. Specifically, in the event that one tooth, hook, or coil is damaged or kinked, the dependency to each of its neighbors is interrupted, causing the closure to fail and allowing the opposing sides to be separated easily. 
         [0006]    Engagement and disengagement of zipper elements requires that the means of support be highly flexible. This often is achieved by using a bias-woven textile strip (commonly called “zipper tape”) that is worn out easily by use and that often is permeable to moisture, dust, and dirt. To alleviate this, supplemental sealing elements may be employed, but these may restrict mobility of the zipper tape. As such, zippers with these added elements are hard to open and close and may have limited flexibility. 
         [0007]    With the advent of technology for extruding polymers, alternatives to zippers have been proposed, such as closures with continuous outer and inner strips of material. However, due to the continuous nature of these strips, closures of this type cannot engage and disengage readily when the plane of closure follows a curve, such as at a corner of a container. Passage of the slider along the length of the closure creates radial differences between the paths of the strips. In turn, the radial differences create differences in the peripheral distance of the inner and outer strips. As a result, the strips may be compressed together, hindering passage of the slider. 
         [0008]    What is needed is a closure device that provides a secure closure with reliability, durability, flexibility, and/or ease of manipulation. For example, the closure may retain its integrity in the event of localized damage and retain its flexibility and ease of use when modified to resist penetration by moisture, dust, and dirt. Additionally, the closure may provide firm engagement and avoid binding at the point of engagement when the plane of closure is curved, such as when the closure turns a corner. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    In one aspect, a closure system may comprise a plurality of first keys coupled to a skirt and a plurality of second keys coupled to a second skirt, each of the first and second keys comprising a base, a finger and a flange, a top and an underside; wherein, when coupled, the underside of a first key is proximate the top of an opposing second key, which may be generally in the plane of closure. The system further may include a slider having a first foot configured to translate proximate the top of the first keys, and a second foot configured to translate proximate the underside of the second keys, said feet configured to press the first and second keys together when the slider is moved in one direction and an interior portion configured to separate the first and second keys when the slider is moved in an opposite direction. 
         [0010]    Each of the first keys further may comprise a protrusion extending away from the underside, and each of the second keys further may comprise an opening extending inward from the top, preferably completely through the second key. In addition, the flanges of the first keys may comprise a narrow portion extending from a respective base and a wider portion extending from the narrow portion. 
         [0011]    In another aspect, a closure system may comprise a plurality of first keys having a base, a finger with a protrusion extending from an underside, and a flange, wherein the base has a thickness larger than a thickness of the finger, and a plurality of second keys having a second base, a second finger with a top having an opening or slot, and a second flange, wherein the second base has a thickness larger than a thickness of the second finger; wherein, when coupled, the underside of a first key is proximate the top of an opposing second key, generally in the plane of closure and wherein, when coupled, the flange and the second flange are generally in the plane of closure. The closure further may include a slider configured to engage and disengage the pluralities of first and second keys, the slider comprising an outer foot proximate the first keys and an inner foot proximate the second keys. The outer foot may include a compressor and a plurality of guides, wherein the guides are configured to receive portions of the base and second base, and the inner foot may include a compressor and a plurality of second guides, wherein the second guides also may be configured to receive second portions of the base and second base. 
         [0012]    The slider may include a splitter between the outer and inner feet, the splitter including a plurality of wedge segments separated by a channel extending at least partially through the splitter. The splitter also may include an upper surface and a lower surface, the surfaces intersecting at both a leading edge and a trailing edge, wherein the splitter is configured to separate engaged first and second keys when moved in a first direction, and the slider may include opposing feet to couple disengaged first and second keys when moved in a second direction. 
         [0013]    In still another aspect, a closure system may include a plurality of first keys separately coupled to a skirt, a plurality of second keys separately coupled to a second skirt, a slider having an outer foot, an inner foot, and a splitter therebetween, the slider configured to translate along the pluralities of first and second keys, wherein, when coupled, the underside of a first key is proximate the top of an opposing second key, generally in the plane of closure, and further wherein engagement of an opposed first key and second key is generally independent of engagement of a neighboring opposed first key and second key. Each of the first keys may comprise a protrusion extending away from an underside, and each of the second keys may comprise an opening extending inward from a top. In addition, each of the first keys may have a height and may comprise a base and a flange extending rearward from the base, wherein the flange is off-centered along the height. Moreover, each of the second keys may comprise a finger having a top, an underside, a proximal end proximate a base, a distal end spaced from the proximal end, and a plurality of sides extending between the top and the underside, from the proximal end to the distal end, wherein each of the plurality of sides tapers inwardly from the proximal end to the distal end. The closure system also may include a sealing strip configured to contact and/or form a seal with first keys and to cover the first and second keys when the keys are engaged. 
         [0014]    These and other features and advantages are evident from the following description of the present invention, with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0015]      FIG. 1  is a perspective view of one embodiment of a closure system. 
           [0016]      FIG. 2  is a perspective view of a pair of opposed keys used with the closure system of  FIG. 1 , one pair of opposed keys shown partially engaged and the second shown disengaged. 
           [0017]      FIG. 3  is a top view of a bottom, or second, key used in a closure system. 
           [0018]      FIG. 4A  is a top view of a top, or first, key used in a closure system. 
           [0019]      FIG. 4B  is a side view of the key shown in  FIG. 4A . 
           [0020]      FIG. 5A  is a perspective view of the underside of the key shown in  FIGS. 4A and 4B . 
           [0021]      FIG. 5B  is a perspective view of the key shown in  FIG. 3 . 
           [0022]      FIG. 6  is a perspective view of a second embodiment of a closure system, which includes a sealing strip. 
           [0023]      FIG. 7  is a perspective view of a slider that may be used with the closure system of  FIGS. 1 and 6 . 
           [0024]      FIG. 8  is a front, perspective view of the outer and inner feet of the slider of  FIG. 7 . 
           [0025]      FIG. 9A  is a perspective view of a splitter that may be used with the slider of  FIG. 7 . 
           [0026]      FIG. 9B  is a rear view of the outer and inner feet and the splitter of the slider of  FIG. 7 . 
           [0027]      FIG. 10  is a side, section view of a closure system, showing a slider engaging an opposed pair of keys. 
           [0028]      FIG. 11  is a perspective view of the closure system of  FIG. 1  extending along a curve. 
           [0029]      FIG. 12  are perspective bottom and top views of a second embodiment of a top, or first, key. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    As seen in  FIG. 1 , a closure system may include opposing rows of keys  20 ,  60 , wherein each opposing pair of keys may be held together by a separable pressure or interference-type fit. Each row of keys  20 ,  60  may be embedded in, and supported by, a skirt  52 ,  92  of flexible material, which may be attached to opposed sides by any convenient means including, e.g., gluing, sewing, bonding, etc. 
         [0031]    Turning to  FIG. 2 , each opposing pair of keys  20 ,  60  may engage and disengage in a plane generally normal to the plane of closure  2 . Engagement and disengagement may be effectuated using a slider that may have a generally “Z”-shaped cross-section comprising a bar connecting inner and outer sides, where the inner surfaces are shaped to separate and deflect keys apart progressively when the slider is moved in an opening direction and to draw and press keys progressively into engagement when the slider is moved in a closing direction. 
         [0032]    Preferably, keys may be displaced by opposite rotation relative to the plane of closure  2 , for example, about axes of rotation  4 ,  6  and/or by vertical movement generally perpendicular to plane of closure  2 . Keys may be constructed so that axes  4 ,  6  may be generally aligned with plane of closure  2 , which may allow plane of closure  2  to be deflected freely without creating radial differences between the rows of outer and inner keys. 
         [0033]    As seen in  FIGS. 2 and 4A , first keys  20  may include a base portion  22  and a finger  24 . Base  22  may have an enlarged height as compared to finger  24 . As such, base  22  may include rib  23  that allows height of base  22  to transition to height of finger  24 . In addition, rib  23  may transition toward finger  24  on top side  34 , underside  36 , or both sides. 
         [0034]    Finger  24  may include a proximal end  26  proximate base  22  and a distal end  28  generally opposite base  22 . First side  30  and second side  32  may extend along a length of keys  20 , e.g., between proximal end  26  and distal end  28 , or between base  22  and distal end  28 . First and second sides  30 ,  32  may be generally planar and, in one embodiment, may be generally parallel to each other. Additionally, first keys  20  each may have a plane of symmetry extending generally perpendicular to plane of closure. First and second sides  30 ,  32  also may include tapered portions  31 ,  33 , respectively, proximate distal end  28 . As discussed below, tapered portions  31 ,  33  may allow first keys  20  to flex and not interfere with adjacent first keys  20 , e.g., when compressing inward. 
         [0035]    Top side  34  may be generally planar surface, although other configurations are possible. For example, top side  34  of keys  20  may include a slight radius of curvature to allow smooth passage under the upper foot of the slider  100  (described below), e.g., to avoid the outer keys  20  trapping against the foot due to slight lifting when traveling on a bend. In another embodiment, as seen in  FIG. 12 , top side  34  may include one or more recessed portions  35 , which may facilitate formation of protrusion  38  without undercuts. 
         [0036]    Turning to  FIGS. 4B and 5A , underside  36  also may be generally planar, however, first keys  20  may include a protrusion  38  extending outward away from underside  36 . Protrusion  38  may be one or more male elements that allow for an engaging or interference fit within opening  78  of second keys  60 . In the embodiment shown here, protrusion  38  may include a plurality of tabs  39 . Tabs  39  may include narrow portions  40  proximate and extending from underside  36 . Wider portions  42  may extend from narrow portions  40  and may couple with, extend past, or otherwise interface with portions of second keys  60  so as to engage closure  10 . In addition, protrusion  38  may include channel  44  between tabs  39 , allowing for compression or expansion of tabs  39  during the engaging and disengaging processes. 
         [0037]    As seen in  FIGS. 2 and 3 , second keys  60  may include several features substantially similar to first keys. For example, second keys  60  may include base  62  with finger  64  extending away from base, with rib  63  located therebetween and tapering height of base  62  toward height of finger  64 . Finger  64  may have a proximal end  66  proximate base  62  and a distal end  68  generally opposite base  62 . Similarly, keys  60  may include a generally planar top side  74  and a generally planar underside  76 , although, as with first keys  20 , variations to these sides are possible. 
         [0038]    Second keys  60  may include first sides  70  and second sides  72 . As with keys  20 , these sides may be generally symmetrical about a central plane of symmetry. Sides  70 ,  72  may be generally parallel. Preferably, however, sides  70 ,  72  may taper inward from proximal end  66  toward distal end  68 . Moreover, sides  70 ,  72  may include secondary tapered portions  71 ,  73  proximate distal end  68  that taper inward more steeply than a remainder of sides  70 ,  72 . Tapering of sides  70 ,  72  and/or secondary tapered portions  71 ,  73  may allow second keys  60  to not interfere with adjacent second keys  60 , e.g., when disengaging keys around a bend, or when closure  10  is flexed inward. 
         [0039]    As opposed to first keys  20 , second keys  60  may include one or more openings  78  or other female elements adapted to receive protrusion(s)  38 . Opening  78  extends inward from top  74  at least partially, and preferably completely, through second key  60 . Opening  78  may include a first sidewall  80  and second sidewall  82  generally opposite opening  78  from first sidewall  80 , as seen in  FIG. 5B . Sidewalls  80 ,  82  may be tapered inward from top surface  74  toward underside  76 , which may provide ramp surfaces along which wider portion  42  of protrusion  38  may slide during engagement of keys  20 ,  60 . As protrusion  38  extends further into opening  78 , protrusion  38  may be compressed until wider portion  42  extends beyond sidewalls  80 ,  82 . At this point, protrusion  38  may expand or at least partially undeform so that wider portion  42  is wider than a distance between sidewalls  80 ,  82 , thereby engaging keys  20 ,  60  and preventing accidental disengagement of keys  20 ,  60 . 
         [0040]    Although one form of engagement is described in greater detail herein, it will be appreciated that opposing keys  20 ,  60  may engage by any form of pressure-fitted or interference-type closure, such as tongue and groove, ball and socket, or other male-female-type connections. 
         [0041]    Returning to  FIG. 2 , bases  22 ,  62  of keys  20 ,  60  may include a flange  46 ,  86  to connect keys to support skirts  52 ,  92 . In one embodiment, flanges  46 ,  86  may be relieved to form a “T” shape, i.e., having narrow portions  48 ,  88  extending away from bases  22 ,  62  and wider portions  50 ,  90  extending away from narrow portions  48 ,  58 . Narrow portions  48 ,  88  proximate bases  22 ,  62  may allow support skirts  52 ,  92  to deflect more easily in a plane outside plane of closure  2 , specifically in a plane generally normal to plane of closure  2 . Wider portions  50 ,  90  allow for sufficient adhesion to support skirts  52 ,  92 . In the embodiment shown in  FIGS. 2 ,  3  and  4 A, wider portions  50 ,  90  are generally rectangular. However, other configurations that allow for wider portions  50 ,  90  to extend beyond width of narrow portions  48 ,  58 , including, e.g., oblong, are possible. Moreover, in another embodiment, instead of discrete narrow portions  28 ,  88  and wider portions  50 ,  90 , flanges  46 ,  86  may include a generally continuous taper outward from bases  22 ,  62 . 
         [0042]    In one embodiment, fingers  24 ,  64  may be substantially centered along height of keys  20 ,  60 , such that about half of bases  22 ,  62  are above fingers  24 ,  64 , and about half of bases  22 ,  62  are below fingers. Flanges  46 ,  86  may be similarly centered. Preferably, however, flange  46  may be offset closer to underside  36 , and flange  86  may be offset closer to top side  74 . For example, center of flange  46  may be offset from center of key  20  by an offset distance OD, as seen in  FIG. 4B . Amount of offset may be such that, when engaged, flange  46  and flange  86  are generally aligned and generally in the plane of closure  2 . 
         [0043]    Keys may include ribs  23 ,  63  for assisting in alignment and engagement of keys  20 ,  60 . In one embodiment, first keys  20  and second keys  60  may be substantially similarly sized and, when engaged, may be substantially aligned along a length of closure  10 . In another embodiment, first and second keys may have edges that are offset when engaged so that keys overlap, which may provide better sealing of closure, e.g., against dirt, moisture, etc. 
         [0044]    As described above, the geometry of the keys may differ depending on whether they are designed to be inner keys  60  or outer keys  20 . Keys  60  located on the inner side of closure  10  may be tapered along their sides  70 ,  72  and/or at their distal ends  68  to avoid interference with each other when closure  10  is deflected, such as at a suitcase corner, or when the inner keys  60  are rotated inward for disengagement with outer keys  20 . Conversely, outer keys  20  may have sides configured so that consecutive keys  20  are generally aligned. Preferably, first side  30  of one outer key may be generally parallel to second side  32  of an adjacent outer key, which may be the case when first side  30  and second side  32  are generally normal to length of closure  10 . Alignment of outer keys  20  may allow outer keys  20  to cover gaps formed between tapered sides  70 ,  72  of inner keys  60 , which may aid sealing properties of closure  10 . 
         [0045]    An impermeable layer of elastic material  200  optionally may be attached by any convenient means to cover the outer row of keys  20 . As seen in  FIG. 6 , material  200  may be extended to cover closure  10  generally to resist penetration by moisture, dust, or dirt. 
         [0046]    Turning now to  FIG. 7 , closure  10  may include a slider  100  to assist in engaging and disengaging opposed rows of keys  20 ,  60 . Puller  102  may be fixed or otherwise coupled to slider  100 , e.g., by a cap  104  or any other convenient means that allows for lateral movement of the puller  102  along the length of the slider  100 . In addition, puller  102  may be coupled as close to plane of closure  2  as possible in order to maximize the linear component of force applied to engage or disengage keys  20 ,  60  and, relatedly, to reduce bending moments applied to puller  102 . 
         [0047]    Slider  100  may include outer foot  106  and inner foot  122  that combine to guide and press opposed keys together, as seen in  FIG. 8 . Outer foot  106  may include a first guide  108  and second guide  110  to allow for passage of second keys  60  and first keys  20 , respectively. Similarly, inner foot  122  may include its own first guide  124  and second guide  126 , also to allow for passage of second keys  60  and first keys  20 , respectively. Guides may function by engaging ribs  23 ,  63  on keys to draw them into alignment with the feet  106 ,  122 . In addition, feet  106 ,  122  may have opposing first tapers  118 ,  136  proximate respective first sidewalls  114 ,  132 . Feet also may have opposing second tapers  120 ,  138  proximate respective second sidewalls  116 ,  134 . Tapers may soften edges of feet  106 ,  122  and also may provide ramp surfaces for outer keys  20 , inner keys  60 , and/or their respective support skirts  52 ,  92 , which may provide more fluid movement of keys into slider  100  during closure. 
         [0048]    Slider  100  also may include splitter bar  140  joining outer foot  106  and inner foot  122 . Splitter bar  140  may join feet directly. Preferably, however, slider  100  may include posts  142 ,  144  to join splitter bar  140  to inside surfaces of outer foot  106  and inner foot  122 , respectively. As seen in  FIG. 9B , combination of outer foot  106 , post  142 , splitter bar  140 , post  144 , and inner foot  122  may form a generally “Z”-shaped profile when viewed in cross-section. 
         [0049]    Turning to  FIGS. 9A and 9B , splitter bar  140  may include a first wedge segment  148  and second wedge segment  150 , separated by a channel  146 . Wedge segments  148 ,  150  may extend laterally from posts  142 ,  144  and may be tapered at both ends, such that upper and lower surfaces may intersect at common edges  152 ,  154 ,  156 ,  158 . These common edges may serve to split engaged keys  20 ,  60  apart when slider  100  passes along the length of closure  10  in an opening direction. In addition, the common edges may guide open rows of keys  20 ,  60  into slider  100  when slider  100  passes along the length of closure  10  in an opposite, or closing, direction. Channel  146  may extend downward from an outer side of splitter bar  140 , i.e., the side closer to outer foot  106 . This may allow passage of the protrusion  38  or other male engaging element of first keys  20 . 
         [0050]    Surface planes  160 ,  162 ,  164 ,  166  of splitter bar  140  may twist or be curved from common edges  152 ,  154 ,  156 ,  158  towards the middle of the bar, which may guide rotational deflection of opposing keys  20 ,  60 . In addition, when moving in an engaging direction, this curvature guides keys from common edges  152 ,  154  toward middle of splitter bar  140 , decreasing the clearance between keys  20 ,  60  and outer foot  106  or inner foot  122  with splitter bar  140 . At some point, e.g., when passing end of channel  146 , clearance is sufficiently minimized, and keys  20 ,  60  are brought close enough together by compressor  112  on outer foot  106  and first and second compressors  128 ,  130  on inner foot  122 , such that protrusion  38  on first key  20  engages opening  78  on second key  60 , thereby causing engagement of keys. Conversely, when moving in a disengaging direction, common edges  156 ,  158  may act as wedges between keys  20 ,  60 , opening a gap between them that expands until protrusion  38  no longer engages opening  78 , at which point keys  20 ,  60  are disengaged. 
         [0051]    Turning now to  FIG. 10 , the interaction of slider  100  on first keys  20  and second keys  60  is shown in cross-section. As can be seen, opposed outer foot  106  and inner foot  122  squeeze opposed keys together between compressors  112 ,  128 ,  130 . Conversely, edges  152  and  154  (see  FIG. 11 ) of splitter bar  140  combine to wedge opposed keys apart. Opposed rows of keys emerge engaged as the slider passes in the closed direction, here, from left to right, and emerge disengaged when the slider passes in the opening direction, here, from right to left. 
         [0052]    In addition to generally linear arrangements, closure  10  also may operate around curves.  FIG. 11  illustrates engagement and disengagement of opposed rows of keys when the plane of closure is curved, e.g., at the corner of a suitcase. Due to the flexible support provided by attachment of first keys  20  via connection between flange  46  and support skirt  52 , keys  20  may be displaced outward and spread apart independently of adjacent keys. Additionally, flexible support provided by attachment of second keys  60  via connection between flange  86  and support skirt  92 , coupled with the tapered geometry of second keys  60  as discussed above, may allow second keys  60  to be displaced inwardly without mutual interference between adjacent keys  60 . Centers or axes of rotation of opposed keys may be in a substantially common plane, which also may be substantially the same plane of closure for each set of opposed keys, which may ensure that peripheral lengths of opposed rows, from one end to the other of closure  10 , are not changed by passage of slider  100 . 
         [0053]    Closure generally, and keys specifically, may be made according to various methods. For example, one method may include molding, trimming, stacking, and feeding keys into a press, for fixing onto a flexible tape. The tape, with keys attached, then may be fed continuously into an extrusion die to be embedded continuously in an extruded flexible skirt. Alternatively, rows of keys may be injection molded, e.g., to predetermined lengths and with thin, frangible supports or films between keys for stabilizing the relative position of keys each beside the next. These rows of keys, still attached to injection sprues, may be transferred to another mold for overmolding a flexible skirt, followed by trimming the completed rows of keys embedded in their skirts. Turning to  FIG. 12 , for injection molding, the outer surface of outer keys  20  may be relieved. This relief may avoid an undercut and also may allow use of a generally simple molding tool to form the protrusion or male engaging member  38 . Additionally, keys and/or puller may be coated with a material that reduces friction, e.g., a TEFLON-type coating. In one embodiment, e.g., closure  10  may be manufactured to have a life span of about 50,000 life cycles, although other life spans are possible. 
         [0054]    Sliders also may be produced according to any convenient methods, including, e.g., die casting or injection molding of parts, followed, to the extent necessary, by assembly using common methods such as snap or press fitting, screwing, riveting, and/or sonic welding. 
         [0055]    While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific exemplary embodiments and method herein. The invention should therefore not be limited by the above described embodiments and method, but by all embodiments and methods within the scope and spirit of the invention as claimed.