Patent Publication Number: US-2016237737-A1

Title: Weatherstrip having undulating base

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62/116,228, filed, Feb. 13, 2015, the disclosure of which is hereby incorporated by reference herein it its entirety. 
    
    
     INTRODUCTION 
     Pile weatherstripping is inserted into slots in windows and/or door frames and provides a barrier to prevent the infiltration and/or exfiltration of air, water, insects, etc. A backing strip or backer of the pile weatherstripping is inserted to a corresponding slot in the frame during assembly. Too much friction between the backer and the slot can make insertion (and subsequent removal) of the weatherstripping difficult or impossible. Too little friction can result in movement between the base and the slot, which may result in the weatherstripping sliding out of the slot, causing a disruption to window manufacturing. 
     SUMMARY 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, is not intended to describe each disclosed embodiment or every implementation of the claimed subject matter, and is not intended to be used as an aid in determining the scope of the claimed subject matter. Many other novel advantages, features, and relationships will become apparent as this description proceeds. The figures and the description that follow more particularly exemplify illustrative examples. 
     In one aspect, the technology relates to a pile weatherstrip having: an elongate base portion having a base portion width and a base portion amplitude greater than the base portion width; and a pile extending from a central portion of the elongate base portion. In an embodiment, the base portion has a first deformation on a first side of the pile and a second deformation on a second side of the pile, and wherein the amplitude is measured from an outer limit of the first deformation to an outer limit of the second deformation. In another embodiment, the first deformation has a first deformation width extending from proximate the pile to the outer limit of the first deformation. In yet another embodiment, the first deformation has a first deformation length extending along the elongate base portion, wherein the first deformation length is greater than the first deformation width. In still another embodiment, a pile support extending from the elongate base portion, wherein the pile is bordered on at least one side by the pile support, and wherein the first deformation contacts the pile support. 
     In another embodiment of the above aspect, the base portion amplitude is about 120% to about 200% of the base portion width. In an embodiment, the first deformation length is about 100% to about 200% of the first deformation width. 
     In another aspect, the technology relates to a weatherstrip having: an undulating elongate base portion; and a pile extending from a central portion of the undulating elongate base portion. In an embodiment, the undulating elongate base portion has an effective width greater than an actual width of the undulating elongate base portion. In another embodiment, the undulating elongate base portion has a non-linear centerline. In yet another embodiment, the undulating elongate base portion has a plurality of deformations, wherein outer limits of the plurality of deformations define an amplitude of the undulating elongate base portion. In still another embodiment, the undulating elongate base portion undulates laterally. In another embodiment, the pile extends substantially orthogonal from the undulating elongate base portion. 
     In another aspect, the technology relates to a weatherstrip having: a substantially uniform elongate base portion having: a first edge; a second edge; and a first deformation formed in a portion of the first edge, wherein a portion of the second edge opposite the first deformation has a curvature. In an embodiment, a second deformation formed in a portion of the second edge, wherein a portion of the first edge opposite the second deformation has a curvature. In another embodiment, a pile extends from the substantially uniform elongate base portion and a pile director bordering the pile. In yet another embodiment, the deformation at least partially contacts the pile director. In still another embodiment, the deformation has a textured surface of the substantially uniform elongate base portion. 
     In another embodiment of the above aspect, the textured surface is formed in an upper surface of the substantially uniform elongate base portion. In an embodiment, a fin is disposed within the pile. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  are top views and partial enlarged top views, respectively, of a weatherstrip in accordance with the prior art. 
         FIG. 2  depicts a perspective view of a weatherstrip in accordance with an example of the present technology. 
         FIG. 3  depicts a top view of a weatherstrip in accordance with an example of the present technology. 
         FIG. 4  depicts an end view of a weatherstrip in accordance with an example of the present technology. 
         FIG. 5  depicts a top view of a weatherstrip and a t-slot, prior to insertion of the weatherstrip. 
         FIG. 6  depicts a top view of the weatherstrip inserted into the t-slot. 
     
    
    
     DETAILED DESCRIPTION 
     Retention technologies utilized in conjunction with pile or other weatherstrips help retain the weatherstrip in the t-slot of a window extrusion. The retention force results from contact and interference between the backing strip of the weatherstrip and the outer walls of the t-slot (typically the outer walls that define the width dimension). It is desirable that the weatherstrip display sufficient retention force so the weatherstrip does not slide out of the slot during window manufacturing processes. However, retention forces that are too high can cause other problems. For example, if the interference is too high, the weatherstrip may not be easily insertable into the t-slot. Once inserted, however, due to differences in material properties, the window frame extrusion and weatherstrip (namely, the backing strip thereof) expand and contract at different rates. As such, if the weatherstrip is held too firmly in the t-slot, the weatherstrip may be damaged as the window frame expands and contracts. Additionally, it is often necessary to remove the weatherstrip after manufacture to replace a damaged weatherstrip. As such, easy removal of the weatherstrip is also desirable. The technologies described herein can be used to retain weatherstrips utilizing pile, foam profiles, rigid plastic profiles, etc., in t-slots formed in door or window frames. For clarity, however, the technologies will be described in the context of pile weatherstrips. 
     Prior retention technologies incorporated into weatherstrips include those depicted and described in U.S. Pat. No. 5,438,802, the disclosure of which is hereby incorporated herein by reference herein in its entirety. These technologies include the formation of so-called “nubbins” in the weatherstrip base. The nubbin of U.S. Pat. No. 5,438,802 is described as a compression of material of the backing strip, which causes a circular, projecting surface to be formed along the edge of the backing strip. The presence of the nubbin purportedly restrains the backing strip in a T-slot of a window frame. Alternative technologies include circular or curved distortions that are formed by punching holes along the edges of the backing strip. In another example, hemispherically-shaped dimples can be formed along an underside of the backing strip. Another example depicts abrasions along the outer edge of the backing strip that form flaps. However, it has been determined that the above-described prior art do not function desirably when the weatherstrip is inserted into a T-slot of a window frame extrusion. 
       FIGS. 1A and 1B  are top views and partial enlarged top views of a weatherstrip  100  manufactured in accordance with the prior art.  FIG. 1A  depicts a pile weatherstrip  100  (with the pile not depicted for clarity) having a backing strip  102  having a nominal width W. Deformations or tabs  104  are formed at alternating intervals along the edges  106  of the backing strip  102 . The deformations  104  extend a distance D from the edge  106  of the backing strip  102  to an outer extent  108  of the deformation  104 . As such, the effective width EW (measured between alternating outer extents  108 ) is the sum of the nominal width W, a distance D to one deformation, and a distance to an opposite deformation. Thus, the effective width may be described as the total lateral space that the weatherstrip  100  occupies. Additionally, the deformations  104  have an inner extent  110  that is spaced a distance P from the pile director  112  (which forms an outer border of the pile, as described below). Notably, after formation of the tabs  104 , the backing strip  102  maintains a straight axis A. 
       FIG. 2  depicts an example of a weatherstrip  100  incorporating the technologies described below. The weatherstrip  200  includes a backing strip  202  that includes outer edges  204 ,  206 . A central portion  208  of the backing strip  202  is disposed between the two edges  204 ,  206 , generally below a pile sealing element  210 , which includes many individual fibers. Pile directors  212 ,  214  extend upwards from the backing strip  202  on either side of the pile  210  so as to form an outer boundary thereof. One or more sealing fins  216  may be present within the pile  210  to further limit air infiltration. The weatherstrip also includes deformations or tabs  218 ,  222  on either edge  204 ,  206  of the backing strip  202 , as described below in more detail. 
     Further discoveries have been made in the field of pile weatherstripping that have resulted in significantly increased performance. It has been discovered that a number of factors can be used to influence the retention performance of weatherstrips. These factors are described in the context of  FIG. 3 , which depicts a top view of the weatherstrip  200  of  FIG. 2 , with the pile removed for clarity. The weatherstrip  200  includes a backing strip  202  that includes outer edges  204 ,  206 . A central portion  208  of the backing strip  202  is disposed between the two edges  204 ,  206 . Pile directors  212 ,  214  extend upwards from the backing strip  202  on either side of the pile (not shown). The weatherstrip also includes deformations or tabs  218 ,  220 ,  222  formed in edges  204 ,  206  of the backing strip  202 . It has been discovered that properly sized and positioned deformations (such as deformations or tabs  218 ,  220 , and  222 ) can cause a curve  224  to form on the portion of the backing strip  202  opposite the deformation  218 ,  220 ,  222 . The deformations or tabs  218 ,  220 ,  222  and the resulting curves  224  cause the backing strip  202  to have a centerline C that is laterally undulating or wave-like in shape. 
       FIG. 3  also depicts relevant measurements of the weatherstrip  200 . The backing strip  202  is characterized by a backing strip width W, which is the width of the backing strip  202  from an outer-most edge  204  to an outer-most edge  206 . Three deformations or tabs  218 ,  220 ,  222  are depicted along the backing strip  202 , although many more deformations may be included on longer weatherstrips. Each deformation has a deformation length L D , measured substantially along a line parallel to an edge of the backing strip  202 . Additionally, each deformation or tab has a deformation width W D , measured substantially from the innermost limit of the deformation (proximate or at the pile deflector) to the outermost limit of the deformation. A deformation length L D  of about 100% to about 200% of a deformation width W D  has been discovered to produce desirable amplitude A. A protrusion distance P is measured from the outermost limit of a deformation or tab to the curved edge on the opposite side of the backing strip  202 . Each deformation on a single side of the backing strip  202  (e.g., deformations or tabs  218  and  222 ) is separated by a spacing S. Additionally, an amplitude A is defined by the space between the outermost extent of a first deformation and the outermost extent of the next closest deformation on the opposite side of the backing strip  202  (e.g., between deformations  218 ,  220  or between deformations  220 ,  222 ). In examples, amplitudes A of about 120% to about 200% of the backing strip width W have been identified as being desirable. Ranges between about 150% and about 180% display promising results. An amplitude A of about 125% of the backing strip width W has also displayed desirable performance. It has been discovered that, by sufficiently deforming the backing strip  202  (e.g., with deformations or tabs  218 ,  220 ,  222 , as well as additional deformations), a curvature may be formed on an opposite edge of the backing strip  202  from the deformation. This alternating curvature-deformation-curvature-deformation pattern, on opposing sides of the backing strip  202  results in a laterally undulating backing strip as depicted by undulating centerline C. This undulation generates a spring force when the backing strip  202  is inserted within a t-slot, the spring force being sufficient to retain the backing strip  202  therein. 
     Various factors may influence the amplitude A of the weatherstrip  200 . Such factors include the size and shape of the deformations or tabs (e.g.,  218 ,  220 ,  222 , and so on), amount of tab projection beyond the edge of the backing strip  202 , width W of the backing strip  202 , the space S between tabs, and the included angle α along the edge of the backer  202  at the intersection of each tab  218 ,  220 ,  222 , and so on. The amplitude A, in one example, is the dimension that represents total lateral space that the weatherstrip  200  occupies. Further, the factors that may influence the insertion, retention, and extraction forces include the number of tabs in contact with the t-slot per unit of length, the shape and size of the tabs, the backing strip  202  thickness and flatness, curvature of the backing strip  202  that results in spring pressure, amplitude A, which creates and undulating or zig-zag backing strip  202 , and material surface finish. 
     When forming the deformations or tabs in the backing strip, punches that are perpendicular to the backer may increase the likelihood of creating an angular offset, zig-zag, and undulating form in the lateral direction of the backing strip. Due to the presence of the pile fibers, however, an embossing wheel mounted on the vertical plane would be likely to capture and distort the pile fibers. An embossing wheel mounted parallel to the backing strip has minimal positive effect on the amplitude A of the zig-zag effect. It has been discovered that an embossing wheel mounted at approximately 45 to 60 degrees from horizontal has an acceptable impact on the amount of amplitude generated. 
     The backing strip temperature during tab formation may be another relevant factor. Residual heat initially generated in the pile weatherstrip manufacturing process as the pile is welded to the backing strip may have a positive effect on the amount of offset generated by the embossing tool. The warm center portion of the backing strip may help the offsetting process due to the discovery that disruption of the pile director facilitates the linear distortion of the edge that results in an angular lateral undulation having an amplitude. 
     Disruption of the pile director has been discovered as another factor to facilitate the undulation of the backing strip.  FIG. 4  depicts an end view of the weatherstrip  200  of  FIG. 2 . When viewed in cross-section, the pile directors  212 ,  214  form a U-shaped channel on the backer  202  in the center of the weatherstrip  200 . When compressing a portion of the backer  202  that extends laterally from one of the pile directors  212 ,  214  to the edges  204 ,  206  of the backer  202 , the two pile directors  212 ,  214  form a reinforced U-shaped channel that resists the linear deformation of the weatherstrip  200 . It has been determined that upon weakening one of the pile directors  212 ,  214  on one side of the backer  202 , linear deformation is facilitated and is easily accomplished by compressing the backer  202  with an embossing tool. Weakening of the pile directors  212 ,  214  can be accomplished mechanically by compressing, cutting, or otherwise manipulating its integrity structurally. As such, tabs  218  may be formed that have a width W D  extending completely from an edge  204 ,  206  to the pile director  212 ,  214 . Weakening the pile directors  212 ,  214  can also be accomplished by heating the center portion of the backer  202 , thereby softening the thermoplastic material that would otherwise reinforce the backer  202 , making it somewhat resistant to angular deformation. Once the pile directors  212 ,  214  have been sufficiently weakened by structural or thermal means, the compression of a deformation  218  easily distorts the straightness of the backer  202  at the point of compression, thus causing a curvature on the opposite edge  204 ,  206 , and forming the desired undulating effect. It is expected that tabs that extend substantially completely to the pile directors may also produce the desired undulation. 
     Referring again to  FIG. 3 , a higher deformation width W D , as well as a higher deformation length L D , both contribute to greater offset amplitude A. It can be desirable that the deformation width W D  reach from the very base of the pile row (e.g., proximate the pile director) to the outermost edge of the backer. In examples, this width W D  is approximately 0.050″. Embossing just a small portion of the edge of the backer, as described in U.S. Pat. No. 5,438,802, is not effective in creating the undulation in the backer. One desirable combination provides tab formation to between 50% and 95% of the backer thickness. Such a deformation width W D  may be for the full width from the pile director to the edge of the backer. Moreover, the tab spacing S may be every 1.5″ to 4″ on the same side. Since the tabs are spaced alternatively on opposite sides, the distance D between tabs on alternating sides is about 0.75″ to about 2″. Formation of tabs on only one side would also be effective. In examples, this distance D may be about 1000% to about 2000% of the deformation length L D . 
       FIG. 5  depicts a top view of a weatherstrip  300  and a t-slot  400 , prior to insertion I of the weatherstrip  300 . The pile is not depicted on the weatherstrip  300  for clarity. The weatherstrip includes a backing strip  302  that includes deformations  304 ,  306 ,  308  as described herein. As can be seen, due to the deformations  304 ,  306 ,  308 , the axis X has achieved an undulating shape desired to produce the spring force of the backing strip  302 . The undulating shape of the axis X thus produces an amplitude A that is wider than a slot width T of the t-slot  400 . The t-slot  400  also includes a throat (the portion of the t-slot  400  through which the pile extends), but the throat is not depicted for clarity.  FIG. 6  depicts a top view of the weatherstrip  300  inserted into the t-slot  400 . Due to the spring force generated by the undulation of the axis X, the inserted amplitude A′ is reduced to be the same as the width T of the t-slot  400 . This spring force allows weatherstrips manufactured to the specifications described herein to be used in t-slots having different widths. This reduces the need to stock different sized weatherstrips and reduces the need for custom manufacturing for specific t-slot widths. 
     Examples 
     T-slots commonly used in window manufacture have nominal widths between about 0.205″ to about 0.215″. In the examples, below, six-foot lengths were tested. It has been determined that removal forces of between about 0.7 pounds/linear foot and about 1.5 lb/lf are desirable. Removal forces of between about 0.7 lb/lf and about 1.0 lb/lf may be more desirable. Lower removal forces may result in the weatherstrip sliding out of the t-slot during window manufacture. Higher forces may prevent the weatherstrip from being removed. 
     A number of examples consistent with the teachings herein were made and tested. Table 1 presents the test results for a number of examples and includes the t-slot width T, backing strip amplitude A, tab spacing S, and removal force. In all cases, the deformations extend to and touch the pile director as described above. This results in the depicted amplitude. In all examples, six-foot lengths of weatherstrips were utilized. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Sample Testing 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 T-slot 
                 Backer 
                   
                   
                 Removal 
                 Removal 
               
               
                 Sample 
                 width T 
                 width W 
                 Amplitude A 
                 Tab spacing S 
                 force (lb.) 
                 force/lf 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 A-1 
                 0.202 
                 0.187 
                 0.235 
                 2.11 
                 8.9 
                 1.48 
               
               
                 A-2 
                 0.202 
                 0.187 
                 0.235 
                 2.11 
                 8.4 
                 1.40 
               
               
                 A-3 
                 0.202 
                 0.187 
                 0.235 
                 2.11 
                 7.1 
                 1.18 
               
               
                 A-4 
                 0.202 
                 0.187 
                 0.235 
                 2.11 
                 9.4 
                 1.57 
               
               
                 A-5 
                 0.202 
                 0.187 
                 0.235 
                 2.11 
                 8.5 
                 1.42 
               
               
                 Average A 
                   
                   
                   
                   
                 8.5 
                 1.41 
               
               
                 B-1 
                 0.209 
                 0.187 
                 0.235 
                 2.11 
                 11.1 
                 1.85 
               
               
                 B-2 
                 0.209 
                 0.187 
                 0.235 
                 2.11 
                 15.3 
                 2.55 
               
               
                 B-3 
                 0.209 
                 0.187 
                 0.235 
                 2.11 
                 11.4 
                 1.90 
               
               
                 B-4 
                 0.209 
                 0.187 
                 0.235 
                 2.11 
                 9.3 
                 1.55 
               
               
                 B-5 
                 0.209 
                 0.187 
                 0.235 
                 2.11 
                 10.1 
                 1.68 
               
               
                 Average B 
                   
                   
                   
                   
                 11.4 
                 1.91 
               
               
                 C-1 
                 0.210 
                 0.187 
                 0.235 
                 2.11 
                 4.5 
                 0.75 
               
               
                 C-2 
                 0.210 
                 0.187 
                 0.235 
                 2.11 
                 6.6 
                 1.10 
               
               
                 C-3 
                 0.210 
                 0.187 
                 0.235 
                 2.11 
                 4.8 
                 0.80 
               
               
                 C-4 
                 0.210 
                 0.187 
                 0.235 
                 2.11 
                 4.8 
                 0.80 
               
               
                 C-5 
                 0.210 
                 0.187 
                 0.235 
                 2.11 
                 4.9 
                 0.82 
               
               
                 Average C 
                   
                   
                   
                   
                 5.1 
                 0.85 
               
               
                 D-1 
                 0.218 
                 0.187 
                 0.235 
                 2.11 
                 1.9 
                 0.32 
               
               
                 D-2 
                 0.218 
                 0.187 
                 0.235 
                 2.11 
                 4.4 
                 0.73 
               
               
                 D-3 
                 0.218 
                 0.187 
                 0.235 
                 2.11 
                 4.4 
                 0.73 
               
               
                 D-4 
                 0.218 
                 0.187 
                 0.235 
                 2.11 
                 4.4 
                 0.73 
               
               
                 D-5 
                 0.218 
                 0.187 
                 0.235 
                 2.11 
                 4.3 
                 0.72 
               
               
                 Average D 
                   
                   
                   
                   
                 3.9 
                 0.65 
               
               
                   
               
            
           
         
       
     
     The results from Table 1 are indicative of the improved performance of the weatherstrips utilizing the undulating backing strip technologies described herein. The average result for test samples A-1 through A-5 is within the desirable 0.7-1.5 lb/lf range, while average result for test samples C-1 through C-5 is within the desirable 0.7-1.0 lb/lf range. It is believed that the test results for samples B and D may be improved by, e.g., adjusting the spacing S of the deformations and/or adjusting the size of the deformations. Other modifications consistent with the disclosure herein may also be made. 
     Methods of manufacturing a pile weatherstrip are described generally in U.S. Pat. No. 7,419,555, the disclosure of which is hereby incorporated herein in its entirety. The deformed and/or embossed pile weatherstrip technologies described further herein may be performed continuously on weatherstrip downstream of the processes described in the above-referenced patent, prior to a reel-up unit that packages the weatherstrip for storage and delivery. Deformation/embossing may be performed as the base portion of the weatherstrip cools (e.g., while still slightly molten). Linear speed of the weatherstrip can be approximately 45 to 60 feet per minute during manufacture. The deformation or embossing unit speed can be driven and timed independently from the machine that manufactures the pile weatherstrip. Alternatively, the embossing unit can be timed with traditional loop-control techniques using a “dancer arm” or Sona-trol™ sensing system to regulate and coordinate the speed of the embossing unit to the pile weatherstrip manufacturing machine. Alternatively, the weatherstrip may be deformed once the base portion has substantially cooled (e.g., at a facility remote from the where the weatherstrip was manufactured). 
     While there have been described herein what are to be considered exemplary and preferred embodiments of the present technology, other modifications of the technology will become apparent to those skilled in the art from the teachings herein. The particular methods of manufacture and geometries disclosed herein are exemplary in nature and are not to be considered limiting. It is therefore desired to be secured in the appended claims all such modifications as fall within the spirit and scope of the technology. Accordingly, what is desired to be secured by Letters Patent is the technology as defined and differentiated in the following claims, and all equivalents.