Abstract:
A method of reorienting directional features associated with manufacture of continuous fastener materials to produce products having such reoriented features, produces fastener products having an array of individual fastener elements extending from a sheet-form base, the fastener elements adapted to engage mating elements for releasable fastening. The method includes the steps of forming a continuous pre-form product having a planar base defining longitudinal edges and an array of fastener elements extending from the base; joining the longitudinal edges of the pre-form product to form a tube having a seam defined by the joined longitudinal edges; and severing the tube across the seam to form the fastener product with segments of seam extending between longitudinal edges of the fastener product. Various techniques for performing the method and various products taking unique advantage of these techniques are disclosed for providing novel fastener products.

Description:
TECHNICAL FIELD  
         [0001]    This invention relates to continuous fastener products and methods and apparatus for forming them.  
         BACKGROUND  
         [0002]    The use of so called “hook and loop” fasteners has become exceedingly prevalent in consumer, industrial and medical applications, and virtually any other situations in which fastening is necessary. Such fastening materials are often advantageously manufactured in continuous strip-form to gain various economies inherent in continuous manufacturing techniques and for convenient shipment and storage in roll form for later use. Methods of continuous manufacture frequently result in continuous fastener products having certain directional characteristics, i.e., features associated with their direction of continuous manufacture (“machine direction”) which are distinct from features perpendicular to their direction of continuous manufacture (“cross-machine direction”).  
           [0003]    While the use of continuously manufactured fastener products is desirable for numerous fastener applications, in some instances the “as-manufactured” direction of the directional features associated with the manufacturing process is less desirable than other possible directional feature orientations. The ability to transform the directional orientation of these directional features to a more desirable direction during continuous manufacture of the fastener product is highly advantageous.  
           [0004]    The invention features a novel method of reorienting directional characteristics of a continuously manufactured fastener product to a more desirable direction. The invention also features a novel continuously manufactured fastener product with reoriented directional characteristics.  
         SUMMARY  
         [0005]    In one aspect the invention provides a method of forming a fastener product having an array of individual fastener elements extending from a sheet-form base, the fastener elements adapted to engage mating elements for releasable fastening. The method includes the steps of forming a continuous pre-form product having a planar base defining longitudinal edges and an array of fastener elements extending from the base; joining the longitudinal edges of the pre-form product to form a tube having a seam defined by the joined longitudinal edges; and severing the tube across the seam to form the fastener product with segments of seam extending between longitudinal edges of the fastener product.  
           [0006]    Variations of this aspect of the invention may include one or more of the following additional features. The step of forming the pre-form product includes continuously extruding resin and continuously molding the resin to form the array of fastener elements integrally with a surface of the pre-form product. The fastener elements of the pre-form product are molded fastener elements overhanging the base to define an overhang direction, the overhang direction in the fastener product extending at least obliquely toward one of the longitudinal edges of the fastener product. The overhang direction of the molded fastener elements in the fastener product extend perpendicular to the longitudinal edges of the fastener product. The base of the pre-form product has a widthwise elastic region corresponding to a longitudinally elastic region in the fastener product. The step of forming the pre-form product includes introducing a sheet-form, uni-directionally elastic material to a pressure gap defined against a rotating mold roll, the uni-directionally elastic material having widthwise elasticity and being longitudinally inelastic to form the widthwise elastic region of the base of the pre-form product corresponding to the longitudinally elastic region in the fastener product. The uni-directionally elastic material includes at least one surface of exposed loop material engageable by the fastener elements. The base of the fastener product is resiliently elastic within its plane. The fastener elements are hook-shaped. The step of severing comprises severing the tube to form a sheet-form fastener product, then slitting the sheet-form fastener product to form multiple continuous strips of fastener product. The step of severing comprises severing the tube along a helical path. The step of joining comprises wrapping the pre-form product to form a tube with opposite longitudinal edges of the pre-form product joined to form a helical seam about the tube; the step of severing including severing the tube along a longitudinal path to form the fastener product. The step of forming the pre-form product further includes shaping selvedge portions along the longitudinal edges of the pre-form product to facilitate joining the longitudinal edges to form the tube.  
           [0007]    In another aspect, the invention provides a method of forming a strip-form fastener product having an array of individual fastener elements extending from a continuous base with the fastener elements being adapted to engage mating elements for releasable fastening.  
           [0008]    The method includes the steps of molding a continuous pre-form product having a planar base and an array of fastener elements extending from the base, the fastener elements overhanging the base to define an overhang direction; joining the longitudinal edges of the pre-form product to form a tube; and severing the tube to form the strip-form fastener product with the overhang direction of the fastener elements extending toward a longitudinal edge of the strip-form fastener product.  
           [0009]    Variations on this aspect of the invention may include one or more of the following features. The step of severing includes severing the tube along a helical path. The step of joining includes wrapping the pre-form product to form a tube with opposite longitudinal edges of the pre-form product joined to form a helical seam about the tube; the step of severing comprising severing the tube along a longitudinal path to form the fastener product.  
           [0010]    In another aspect, the invention provides a continuous strip-form fastener product of finite width and having two longitudinal edges, the product including a series of joined pre-form tape segments, each having a planar base with opposite machine direction edges extending between longitudinal edges of the product, and an array of fastener elements extending from the base and arranged in rows parallel to the machine direction edges, adjacent tape segments permanently joined along seams at their machine direction edges.  
           [0011]    Variations on this aspect of the invention may include one or more of the following additional features. The array of fastener elements includes rows of molded hooks, each hook having a head overhanging the base in a direction parallel to the machine direction edges of the pre-form tape segments and a direction extending toward a longitudinal edge of the fastener product. The pre-form tape segments further include elastic zones having resiliency in a direction transverse to the machine direction edges of the pre-form tape, the elastic zones forming zones of increased longitudinal elasticity in the strip-form fastener product. At least one surface of the elastic zones includes a loop material engageable by the fastener elements.  
           [0012]    The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.  
       
    
    
     DESCRIPTION OF DRAWINGS  
       [0013]    [0013]FIG. 1 illustrates a continuous strip of fastener product of the invention.  
         [0014]    [0014]FIG. 2 is an enlarged view of the area indicated by Circle  2  of FIG. 1.  
         [0015]    [0015]FIG. 2A is a view similar to that of FIG. 2 illustrating an alternative hook arrangement.  
         [0016]    [0016]FIG. 3 is a diagrammatic illustration of a method and apparatus for producing the fastener product of FIG. 1.  
         [0017]    [0017]FIG. 4 is a view similar to that of FIG. 1 illustrating a pre-form product for producing the fastener of FIG. 1.  
         [0018]    [0018]FIG. 5 illustrates the pre-form product of FIG. 4 being processed to form the fastener product of FIG. 1.  
         [0019]    [0019]FIG. 6 is a view similar to that of FIG. 5 illustrating an alternative method of forming the fastener product o FIG. 1 from the fastener product of FIG. 4.  
         [0020]    [0020]FIG. 7 illustrates an alternative embodiment of a continuous strip of fastener product of the invention.  
         [0021]    [0021]FIG. 7A illustrates the fastener product of FIG. 7 in a stretched condition.  
         [0022]    [0022]FIG. 8 illustrates an application of the fastener product of FIG. 7.  
         [0023]    [0023]FIG. 9 illustrates a pre-form product for producing the fastener product of FIG. 7.  
         [0024]    [0024]FIG. 9A is a view taken from the direction of line  9 A— 9 A of FIG. 9.  
         [0025]    [0025]FIG. 9B illustrates marginal edge portions of a cross-section of the pre-form product of FIG. 9 during processing to form the fastener product of FIG. 7.  
         [0026]    [0026]FIG. 10 illustrates a pre-form product for producing the fastener product of FIG. 12.  
         [0027]    [0027]FIG. 11 is a view taken along line  11 — 11  of FIG. 10.  
         [0028]    [0028]FIG. 11A is a highly enlarged view of the area indicated by circle  11  A of FIG. 11.  
         [0029]    [0029]FIG. 12 illustrates an alternative continuous fastener product of the invention.  
         [0030]    [0030]FIG. 13 illustrates strips of the fastener product of FIG. 12 partially fastened to each other. 
     
    
       [0031]    Like reference symbols in the various drawings indicate like elements.  
       DETAILED DESCRIPTION  
       [0032]    [0032]FIG. 1 illustrates a continuous strip of fastener product  10  having a flexible planar base  12  defining opposite longitudinal edges  14 ,  15  along its width “w”. A multitude of fastener protrusions, e.g., hook-like elements  16 , arranged in parallel rows protrude from base  12  and equally spaced seams  18  traverse the width of base  12  in a direction parallel that of the hook rows, i.e., along line A. Hooks  16  are formed integrally from the same material as plastic base strip  12  as described below.  
         [0033]    Referring now also to FIG. 2, hooks  16  project from base  12  and are equipped with a crook  20  for engaging mating fastener material, e.g., hook-engageable loop material. Each crook  20  projects out from a stem  22  to define an overhang direction (arrow d in FIG. 2) relative to base  12 , the direction of overhang being parallel to the rows of hooks  16 . A suitable shape for hooks  16  is, for example, of CFM-29 designation, available from Velcro USA Inc. of Manchester, N.H. The CFM-29 hooks are only 0.015 inch (0.38 mm) in height h, with a width w h  of 0.017 inch. The thickness of the base material is 0.005. Alternative protrusion shapes, such as mushrooms, palm trees, flat-topped hooks, or other loop-engageable shapes are also suitable.  
         [0034]    [0034]FIG. 2A illustrates an alternative, currently preferred, arrangement of hooks  16  having hooks of alternate rows overhanging base  12  in opposite, parallel directions (as indicated by arrows d, d′).  
         [0035]    [0035]FIG. 3 illustrates a method and apparatus for producing the above described fastener product. The method builds upon the continuous extrusion/roll-forming method for molding fastener elements on an integral, sheet-form base described by Fischer in U.S. Pat. No. 4,794,028, the contents of which are hereby incorporated by reference. The relative position and size of the rolls and other components are not to scale. An extrusion head  30  supplies a continuous sheet of molten resin  32  to a nip  34  between a rotating mold roll  36  and a counter-rotating pressure roll  38 . Mold roll  36  contains an array of miniature, fastener element-shaped mold cavities extending inward from its periphery for molding the fastener protrusions, e.g. hooks  16  (FIGS. 1, 2). Pressure in nip  34  forces resin into the fastener element cavities and shapes the resin to form the substrate (base  12  in FIG. 1). The formed product is cooled on the mold roll until the solidified fastener elements (e.g., hooks  16 ) are stripped from their fixed cavities by a stripper roll  42 .  
         [0036]    Referring now also to FIG. 4, the product  50  that is stripped from the mold roll  36  is the pre-form product for use in making the above described fastener product  10  through processing further described below. Pre-form product  50  includes both fastener elements  16 ′ and base  12 ′ and is a seamless continuous strip of fastener tape having parallel opposite longitudinal edges  52 ,  53  that are formed in a direction tangential to nip rolls  36 ,  38 . This tangential direction is also known as the machine direction of the pre-form process. Crooks  22  of hooks  16  overhang base  12  in a direction (arrow d in FIG. 2) parallel to the machine direction.  
         [0037]    Referring again to FIG. 3, pre-form product  50  proceeds from stripper roll  42  to a stationary mandrel  60 . Folding plate  56  wraps pre-form product  50  in a width-wise manner about mandrel  60  bringing longitudinal edges  52 ,  53  to an overlapping or adjacent position. Joining apparatus  58  then joins longitudinal edges  52 ,  53 , e.g., by heat staking, adhesive, ultrasonic bonding, or any other known method of bonding plastics, to form a tubular fastener product  64  (see FIG. 5) having a seam  65  formed at the joined longitudinal edges. Mandrel  60  typically has a circumference slightly smaller than the width of pre-form product  50  so that wrapping of pre-form product  50  about the mandrel allows some overlap of longitudinal edges  52 ,  53 . Alternatively, mandrel  60  has a circumference slightly greater than the width of pre-form product  50  and another material, e.g., hot-melt adhesive, is introduced between the edges to accomplish the joining and form seam  65  (FIG. 5).  
         [0038]    Located on mandrel  60  at a position downstream from the longitudinal edge joining apparatus  58  is a rotating collar  70  which is equipped with a bias cutter  66 . As the tubular product passes over rotating collar  70 , bias cutter  66  cuts the tubular product continuously on the bias to convert the tubular product into ribbon form  10 . The resulting fastener product  10  is then stripped from mandrel  60  and wound into a continuous roll of fastener product or is further split by a cutter  68  into multiple fastener tape products ( 2  fastener tape product rolls,  67 ,  69  are shown in FIG. 3, but additional splitting may be performed as desired).  
         [0039]    The resulting fastener product  10  has all of the features discussed above in reference to FIG. 1. The above described process transforms machine direction longitudinal edges  52 ,  53  of pre-form product  50  into transverse seams  18  and provides fastener product  10  having a crook overhang direction (arrow d in FIG. 2) parallel to seams  18 , i.e., the crooks overhang base  12  in a direction transverse to longitudinal fastener tape edges  14 ,  15 .  
         [0040]    [0040]FIG. 6 illustrates an alternative process for transforming pre-form product  50  to product fastener tape  10 . Again referring also to FIG. 3, to transform pre-form product  50  as illustrated in FIG. 6, stationary mandrel  60  is replaced with a rotating mandrel (not shown). As pre-form product  50  is introduced onto the rotating mandrel, the rate of mandrel rotation is coordinated with the feed speed of pre-form product  50  and its approach angle to rotating mandrel  60  so that pre-form product  50  is wrapped about the rotating mandrel with longitudinal edges  52 ,  53  in adjacent wraps either overlapped or slightly spaced adjacently as described above. Joining apparatus  58  is positioned on the bias to bond overlapped or adjacent longitudinal edges as the mandrel turns to form a spiral seam  82  along the resulting tubular fastener product  80 . Tubular fastener product  80  exits mandrel  60  and is straight-cut by a stationary cutter along a line parallel to the central axis of tubular fastener product  80  to form fastener tape  10 .  
         [0041]    In another embodiment, illustrated in FIG. 7, a fastener product  90  similar to that of FIG. 1 is formed having stretchy zones  92  of a relatively elastic material interposed between relatively inelastic bands  94  of rows of fastener elements, e.g., hooks  16  of FIGS. 1 and 2. For ease of manufacturing, as further described below, the elasticity of the material of zones  92  is limited to a direction orthogonal to seams  96  and the material is relatively inelastic in a direction parallel to seams  96 . The resulting fastener product  90  has a degree of longitudinal stretchiness, i.e., fastener product  90 , in relaxed condition (FIG. 7), has inelastic bands  94  of rows of fastener elements of width w h  and stretchy zones  92  of width w s , and in tension (arrows T, FIG. 7A) inelastic bands  94  of rows of fastener elements remain of width w h  while stretchy zones  92  have increased width w S1 .  
         [0042]    In one particularly important example of the embodiment of FIG. 7, uni-directionally stretchy material of zones  92  has at least its surface opposite the bands of hooks comprised of a hook-engageable loop material engageable by fastener elements, e.g., hooks of bands  94 . As illustrated in FIG. 8, this allows the fastener tape  90  to be pulled from a continuous roll  97 , stretched, wrapped, and continuously fastened to itself in its stretched condition about, for example, a human joint, e.g., elbow  98 , to support the joint. The fastener tape can then be cut to a desired length.  
         [0043]    Fastener product  90  is formed by a modification of the above-described process in which the material of elastic zones  92  is laminated to bands  94  of rows of hooks. In one example, the modified process builds upon the continuous extrusion/roll-forming method for molding fastener elements on an integral, sheet-form base of previously incorporated U.S. Pat. No. 4,794,028, and the nip lamination process described by Kennedy et al. in U.S. Pat. No. 5,260,015, the contents of which are hereby incorporated by reference.  
         [0044]    Referring to FIG. 9, pre-form product  50 ′ is produced having a multiplicity of spaced narrow longitudinal (machine direction) bands  92 ′ of fastener hooks, similar to those described above, on a base of uni-directionally stretchy loop material  94 ′. Bands of stretchy loop material are exposed between the spaced bands  92 ′ of fastener hooks. Pre-form product  50 ′ presents a striped appearance sometimes referred to here as a “zebra-like” appearance. For further details of producing such “zebra-like” materials, and for variations of “zebra-like” products and materials, processes, and apparatus for making such products, the reader is referred to co-pending U.S. patent application Ser. No.______, to Krantz et al., entitled “Hook and Loop Fastening”, and filed Oct. 24, 2000, the entire contents of which are hereby incorporated by reference.  
         [0045]    One such “zebra-like” product, illustrated in FIGS. 9 and 9A, is made by modifications to the process described above with reference to FIG. 3. As more fully described in the above incorporated references, pre-form product  50 ′ (FIGS. 9, 9A) is formed by an in situ lamination process in which molten resin  32  is extruded through nip  34 . However, in this embodiment, extruder head  30  is equipped with a slot-form die (not shown) to provide molten resin  32  in multiple narrow bands spaced at predetermined intervals across the width of nip  34 . Mold roll  36  has fastener element-shaped mold cavities in regions corresponding to the narrow bands of resin. As indicated by dashed lines, uni-directionally stretchy (i.e., stretchy only in the cross-machine direction as indicated by arrows CM in FIG. 9) loop material  92 ′ is simultaneously fed into nip  34  and is at least partially penetrated by the bands of resin  32  while the bands  94 ′ of resin are also molded to have fastener elements  16  extending from a surface to in situ laminate bands  92 ′ of fastener elements to loop material  92 ′.  
         [0046]    The relative inelasticity of loop material  92 ′ in the machine direction advantageously allows suitable machine direction tension to be maintained on the material to ensure that it tracks well to the machine, and can be removed from the machine without undue concern as to the complete solidification of the resin, or risk that the web will wander from its desired track or wrinkle or otherwise distort.  
         [0047]    Pre-form product  50 ′ is removed from mold roll  36  by stripper roll  42  and is then formed into a tube, welded, and cut into strips of desired width in a process similar to those described above with reference to FIGS. 5 and 6. The resulting fastener product  90  (FIG. 7) has a degree of longitudinal stretchiness due to the transformation of seamless, width-wise stretchy, pre-form product  50 ′ into a continuous series of bonded transverse bands of fastener material that is stretchy in a direction orthogonal to seams  96 .  
         [0048]    Referring now to FIGS. 9A and 9B, pre-form product  50 ′ (or pre-form product  50  of FIG. 4) advantageously has selvedge portions  152 ,  153  along longitudinal edges  52 ′,  53 ′ formed of thermoplastic resin. Thermoplastic selvedge portions  152 ,  153  facilitate joining longitudinal edges  52 ′,  53 ′ by e.g., thermobonding, during formation of the tubular fastener product  64 ′ (FIG. 9B) from which fastener product  90  is cut, as in the above described process. Selvedge portions  152 ,  153  have tapered surfaces  154 ,  155 , respectively, that allow the longitudinal edges to have an overlapped thickness, t, (FIG. 9B) that differs insubstantially from the thickness of the base of fastener product  90  so that the profile of seams  96  is minimized. Additionally, thermoplastic selvedge portions  152 ,  153  can be shaped to form, e.g., tongue in groove, dovetail, or other mating arrangements, to aid in alignment of longitudinal edges  152 ,  153  during the joining of longitudinal edges.  
         [0049]    Selvedge portions  152 ,  153  can be formed by modifying the above described process to provide extruded strips of resin  32  along longitudinal edges of loop material  92 ′ as it is fed through nip  34  so that the resin strips at least partially penetrate and bond to loop material  92 ′. The resin strips are formed into selvedge portions  152 ,  153  of desired shape by providing corresponding appropriately shaped portions of mold roll  36  and pressure roll  38 .  
         [0050]    In another embodiment, illustrated in FIGS.  10 - 12 , a “zebra-like” pre-form product  50 ″ is produced having a multiplicity of alternating narrow longitudinal (machine direction) bands  94 ″ of fastener hooks and narrow longitudinal bands  92 ″ of fastener hook-engageable loop material. Both the fastener hook bands  94 ″ and the fastener hook-engageable bands are exposed on the same surface of pre-form product  50 ″. The underlying base  12 ″ of pre-form product  50 ″ and the bands  94 ″ of fastener hooks are of the same relatively inelastic material.  
         [0051]    Pre-form product  50 ″ is made by another modification to the above described process wherein, referring again to FIG. 3, a single band of resin  32  sufficient to form the entire base of pre-form  50 ″ is fed into nip  34  simultaneously with narrow bands  92 ″ of loop material (a single band of such loop material is represented by dashed lines in FIG. 3) spaced at desired intervals. Mold roll  36  has spacer rolls to accommodate bands of loop material  92 ″ with adjacent bands of rows of hook cavities to form bands  94 ″ of fastener hooks. As the bands of loop material are fed through the nip, they are in situ laminated to the base and hook band forming resin, i.e., the loop bands are at least partially penetrated by the molten resin as described above and illustrated in FIGS. 11, 11A, to be permanently bonded to the base  12 ″.  
         [0052]    Subsequently, pre-form product  50 ″ can be helically converted, as described above with reference to FIGS. 3, 5, and  6 , to form the fastener product  90 ″ illustrated in FIG. 12 having a series of seams  96 ″ parallel to alternating angled bands  94 ″,  92 ″ of hook and loop fasteners. Such a fastener product can be self-engaged, as illustrated in FIG. 13, by exposing hook and loop band bearing surfaces of the product  90 ″ for face-to-face contact. Through the helical conversion process described above, the bands of hook and loop are angled to allow opposing fastener portions to be presented for fastening with opposite angular orientations of the hook and loop bands (as shown in FIG. 13). This opposite angular orientation avoids a potential failure of opposing fastener portions, e.g., of fastening material that has not been helically transformed as described herein, to fasten caused by loop band to loop band and hook band to hook band alignment of opposing fastener portions, i.e., the opposite angular orientation of the bands ensures contact of a portion of a loop band of one opposing fastener portion with a portion of a hook band of another opposing fastener portion to achieve fastening.  
         [0053]    A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.