Patent Abstract:
A fastener assembly is for use in an associated fastener driving tool. The assembly includes a row of fasteners arranged substantially parallel to each other. Each fastener has a shank and defines an axis. A collation system is formed from a plastic material that is molded onto and adhered to the fasteners. The plastic material defines a collar portion at least substantially encircling the fastener shank and a connecting portion extending between and connecting adjacent collar portions. The connecting portion includes a bridge and a rib. The bridge is a relatively thin, elongate element spanning adjacent collar portions and the rib is a relatively thick, short element that is disposed at about an upper portion of the bridge. When the fastener is driven from the driving tool, the collar portion remains adhered to the fastener such that the collar portion penetrates the substrate with the fastener. The connecting portion can include a weakened region for separating the connecting portion from the collar.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATION DATA 
     This application is a continuation-in-part of U.S. patent application Ser. No. 11/734,684, filed Apr. 12, 2007, which is a continuation-in-part of U.S. patent application Ser. No. 11/383,032, filed May 12, 2006. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention pertains to collated fasteners. More particularly, the present invention pertains to a collated nail strip formed with a debris-free plastic material for use in a fastener driving tool. 
     Fast-acting fastener driving tools are in widespread use in the construction industry. Such tools are used in industries ranging from re-fabricated housing construction to luxury residential, commercial and industrial construction. For use in these tools, the nails are assembled in strips that are inserted into a magazine of the tool. The strips are flat and the nails or other fasteners are held parallel to one another. The nails are assembled in a staggered or stepped manner such that the major axis of the nail forms an angle to the longitudinal direction of the strip. In presently known collated nails, the angle is about 0 degrees to 40 degrees and preferably between 15 degrees and 35 degrees. An in-depth discussion of such fasteners is provided in U.S. Pat. No. 5,733,085, to Shida, which is incorporated herein by reference. The strips can also be “rolled” or formed into coils for use in certain tools. 
     Presently known collated nails are assembled using tape strips or an extruded plastic material. The molten plastic (or polymer) in the plastic-formed strips is cooled and hardens to hold the nails in the strip form for use in the tool. The tape strips are formed from a kraft paper or other paperboard material having a plastic (polymer) adhesive on a surface thereof that is heated on contact with hot nails and, as it cools, adheres to the nails. 
     Although tape strips have the advantage of minimizing the debris that is formed as the tool is actuated and the nails are driven into the material (typically wood) to be fastened, the plastic strips provide ease of manufacture, especially for larger spaced nails. No materials, other than the nails and the plastic collating material are needed. 
     However, it has been noted that as the plastic collated nails are driven into the workpiece, the plastic material, not adhering to the nail, shatters and separates from the nail shank. This can create loose debris at the worksite which can result in housekeeping problems. 
     Accordingly, there is a need for a plastic collation system for strip-formed fasteners that reduces the tendency for the plastic to generate debris as the nail is driven into the workpiece. Desirably, the collation system reduces the tendency for the nail strip to corrugate or advance on itself in the tool magazine. More desirably, such a system minimizes the amount that the strip can flex, and maximizes the adhesion of the plastic to the nail shanks. More desirably still, such a system is configured to permit the collation to be coiled for use in driving tools that accept collations in this manner. 
     BRIEF SUMMARY OF THE INVENTION 
     A fastener assembly is for use in an associated fastener driving tool for driving a fastener from the assembly into an associated substrate, such as a wood substrate. The fastener assembly includes a row of fasteners arranged substantially parallel to each other. Each fastener has a shank. 
     A collation system is formed from a plastic material that is molded onto and adhered to the fasteners. The plastic material defines a collar portion that captures or at least substantially encircles the fastener shank and a connecting portion extending between and connecting adjacent collar portions. The plastic material is formulated from an adhesive polymer such as a polyolefin, a polyolefin blend, an epoxy or the like. When the fastener is driven from the driving tool, the collar portion remains adhered to the fastener such that the collar portion penetrates the substrate with the fastener. 
     In a present strip, the polymer is a blend of polypropylene and a maleic anhydride modified polypropylene and adhesion is effected by preheating the fasteners prior to molding the plastic material to the fasteners. A preferred preheating temperature is about 450° F. and preferably about 450° F. to 600° F. 
     In the strip, the fasteners are parallel to one another and at an angle relative to an axis of a selected one of the fasteners. 
     The connecting portion can be formed as a bridge and a rib in which the bridge and rib have a generally cruciform shape. The rib can be formed parallel to the collation. Alternately, the rib can be formed at an angle (not parallel to) the collation. Alternately still, the connecting portion has an embossed pattern formed therein. 
     In a present strip, the collation system includes upper and lower plastic moldings adhered to the fasteners. The upper and lower plastic moldings are formed parallel to one another, with the upper molding formed nearer to the head of the fastener and the lower molding formed nearer to the tip of the fastener. The lower molding is formed on the shank of the fastener within the lower half and preferably within about ½ inch of the tip of the fastener. The plastic molding can be formed having a taper to facilitate penetration into the substrate. 
     A method for making a fastener assembly includes the steps of arranging a plurality of fasteners in a row parallel to one another, preheating the plurality of fasteners to elevate the temperature of the fasteners, molding a polymer material onto the preheated fasteners and between adjacent fasteners to form a plastic collation having a collar that captures or at least substantially encircles a shank of each fastener and a connecting portion between adjacent fasteners and cooling the strip to form the fastener assembly. The strip can then be post heat treated. 
     The fastener assembly can also be configured to influence or encourage separation of the fasteners from one another (separation of the connecting portions) at a desired location. Such a configuration further reduces debris by reducing the impact on the connecting portion by the fastener as it is driven by the tool into the substrate. 
     The fastener assembly includes a row of fasteners arranged substantially parallel to each other and a collation system formed from a plastic material that is molded onto and adhered to the fasteners. The connecting portion includes a preferentially weakened region to influence separation of the connecting portion from the collar at a desired location. 
     A preferred preferentially weakened region is at about a juncture of the connecting portion and the collar portion, and most preferred a juncture of the connecting portion and the collar portion of a subsequent fastener in the row of fasteners. 
     The preferentially weakened region can be formed by a notch in the connecting portion, such as at an upper edge of the connecting portion. A notch can also be formed in a lower edge of the connecting portion. The upper edge notch can have an arcuate wall. 
     The preferentially weakened portion can be formed by the connecting portion having a varying cross-sectional area with a smaller cross-sectional area at the desired location than at other locations in the connecting portion. The connecting portion can include a bridge and a rib, such that the varying cross-sectional area corresponds to transitions between the rib and the collar portions being formed having different radii of curvature. The preferentially weakened region can be formed by a smaller cross-sectional area at the juncture of the connecting portion and the collar portion of a subsequent fastener in the row of fasteners than at a juncture of the connecting portion and the collar of the driven fastener. 
     The fasteners can also be positioned eccentrically relative to their respective sleeves to define a thin-walled sleeve section at the desired location. 
     The assembly can also be configured with the connecting portion including a rib that extends less than an axial length of the collar portion (e.g., is not as long as the collar), and the rib can have a width that is greater than the width of the collar. 
     The connecting portion can include a bridge that is integral with the rib and extends substantially the axial length of the collar portion, such that the rib and bridge have a substantially cruciform shape. 
     The rib can be tapered, narrowing toward the tip of the fastener, and the bridge can be tapered, narrowing toward the tip of the fastener. The rib can be a relatively thick, short element disposed at about an upper portion of the bridge. The rib can have a tapered shaped, narrowing in a direction proximal to a tip of the fastener. The taper can be incorporated into a diamond shaped rib. 
     The assembly can include upper and lower collations parallel to and spaced from one another. In such as a configuration, the lower collation (that is the collation closer to the tip) is narrower that the upper collation. Preferably, the lower collation is about ½ of the width of the upper collation. 
     These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The benefits and advantages of the present invention will become more readily apparent to those of ordinary skill in the relevant art after reviewing the following detailed description and accompanying drawings, wherein: 
         FIG. 1A  is a plan view of one embodiment of a nail strip or collation having a pair of plastic molded carrier strips, and  FIG. 1B  illustrates a coiled collation configuration; 
         FIG. 2  is a cross-sectional view taken along line  2 - 2  of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view taken along line  3 - 3  of  FIG. 1 ; 
         FIG. 4  is an illustration similar to  FIG. 2 , showing a tapered collar; 
         FIGS. 5A and 5B  illustrate portions of strips having angled ribs; and 
         FIGS. 6 and 6A  illustrate an alternate bridge portion that is embossed, in which  FIG. 6A  is a cross-section taken along line  6 A- 6 A of  FIG. 6 ; 
         FIGS. 7A and 7B  illustrate the locations at which a leading of driven nail is separated from the nail strip, in which  FIG. 7A  is a leading nail separation and  FIG. 7B  is a trailing nail separation; 
         FIGS. 8A and 8B  illustrate various notch locations and configurations; 
         FIGS. 9A and 9B  are cross-sectional views of embodiments of nail strips with concentric ( FIG. 9A ) and eccentric ( FIG. 9B ) nail placements and having large and small radius bridge to collar transitions; 
         FIGS. 9C and 9D  are a cross-sectional view and an enlarged partial cross-sectional view of a nail strip with a reduced thickness neck area; 
         FIGS. 10A and 10B  are alternate embodiments of stiff rib thin bridge ( FIG. 10A ) and no bridge ( FIG. 10B ) nail collation connecting portions; 
         FIGS. 11A-11E  illustrate embodiments of the nail collations with tapered connecting portions; 
         FIG. 12  illustrates still another embodiment in which the upper and lower collations have different widths; 
         FIGS. 13A and 13B  illustrate still another embodiment in which the fasteners include a penetration expanding portion; 
         FIGS. 14A and 14B  illustrate still another embodiment in which the nail shanks have deformations thereon, below the plastic carrier strips; and 
         FIGS. 15A and 15B  are side and partial cross-sectional views of still another embodiment of the nail collation system. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiment illustrated. 
     It should be further understood that the title of this section of this specification, namely, “Detailed Description Of The Invention”, relates to a requirement of the United States Patent Office, and does not imply, nor should be inferred to limit the subject matter disclosed herein. 
     Referring now to the figures and in particular to  FIG. 1 , there is shown a nail strip  10  having a plastic collation system  12  embodying the principles of the present invention. In the illustrated strip  10 , the nails  14  are positioned at an angle α of about 20 degrees to the transverse direction of the strip  10 ; however, other angles α (including zero degrees) are contemplated for use with the present invention. The strip in  FIG. 1B  is a coiled collation. 
     As will be appreciated by those skilled in the art, the illustrated nails  14  are full head nails, rather than D-head (or clipped head) nails. Accordingly, the nails  14  provide increased holding characteristics (due to the increased surface area of the nail head H). However, it will also be appreciated that using full head H nails  14  requires that the strip  10  is fabricated with a slightly greater distance d 14  between the (axes A 14  of the) nails  14  to accommodate the larger nail heads H. 
     The nails  14  are collated and held to one another by the plastic collation  12 . The plastic collation  12  is molded to, over and around the shanks  16  of the nails  14 , and connects each nail  14  to its adjacent nail or nails (that is, extends between the nails  14 ). The collation  12  is formed as a contiguous molding (as indicated generally at  18 ) around and between the nails  14 ; nevertheless, for purposes of this disclosure, the molding  18  is viewed as having a collar portion  20 , which is that portion that encircles the nail shank  16 , and a connecting portion  22 , which is that portion that extends between and connects adjacent collar portions  20 . In the nail strip  10  illustrated in  FIG. 1 , two plastic moldings or collations are shown, namely an upper molding or collation  12   a  and a lower molding or collation  12   b , that are formed with structure similar to one another. The following disclosure is applicable for both of the moldings and are referred to collectively as molding or collation  12 . For purposes of the present disclosure, the term molded is intended to include all methods of forming the collation  12  on or to the nails  14 . 
     The present nail collation  12  differs from previously known plastic collations in a number of important aspects. First, rather than the plastic merely encircling and extending around and between the nails, the present collation uses a material that is molded (or formed) and adheres to the nails  14 . It has been found that plastic that is adhered to the nails, rather than merely molded around the nails is advantageous in that the plastic material tends to remain on the nail shank  16  during driving. That is, the collation  12  material is maintained on the shank  16  as the nail  14  penetrates the substrate and thus enters the substrate with the nail  14 . Advantageously, much less debris is generated during driving of a nail  14  from the present nail strip  10  compared to prior known nail strips. 
     It will also be appreciated that the adhesion of the plastic material to the nails  14  also has benefits vis-à-vis the rigidity of the nail strip  10 . That is, when the plastic merely encircles the nail shanks, the plastic can slip around the nail shanks. On the other hand, by adhering the plastic molding  12  to the shanks  16 , the nail strip  10  tends to become more rigid and is less likely to flex and to corrugate. 
     The material is an adhesive polymer, an epoxy or the like. The material can be, for example, an adhesive polyolefin such as a maleic anhydride modified polyolefin, such as polypropylene, polyethylene or the like. The material can include a blend of a polyolefin and a modified polyolefin, such as a blend of polypropylene and a maleic anhydride modified polypropylene. One or more other resins can also be used, such as a polyvinyl alcohol (PVA) based material, an ethylene vinyl alcohol (EVA) based material, an acrylonitrile butadiene styrene (ABS) based material, ionomers, methyl methacrylates and the like. Fillers can also be used as can blends of any of the materials, as suitable. Other materials will be recognized by those skilled in the art and are within the scope and spirit of the present invention. 
     A present plastic composition is a polypropylene resin that has been modified to enhance adhesion to surfaces, including metal surfaces. A preferred resin is a maleic anhydride modified polypropylene commercially available from Mitsui Chemicals America, Inc, of Rye Brook, N.Y., under the tradename ADMER® QF5512A. 
     It has been found that unexpectedly high levels of adhesion were achieved using these modified resins when the resins were applied to nails  14  that were heated to elevated temperatures prior to application of the polymer (resin). Samples of nails were prepared by preheating the nails to a temperature of about 450° F. to about 600° F., and preferably about 500° F. to 550° F. and molding the maleic anhydride modified polypropylene to the nails. These were tested against other molded nail strip compositions, in which the molding was carried out with the nails at ambient temperature and with the nails at elevated temperatures (shown as Cold and Hot under column listed as Nail Temp). Tests were also carried out with strips that were postmolding heat treated (shown in columns identified as As Extruded and After 30 Min. Bake). That is, after the plastic material has been molded to the nails, the nail strip was heated for a period of time (30 minutes) at a predetermined temperature. The results of the testing are shown in Table 1, below. 
     
       
         
               
             
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 PLASTIC ADHESION SHEAR STRENGTH OF 
               
               
                 VARIOUS PLASTIC NAIL COLLATIONS 
               
             
          
           
               
                   
                 Plastic Adhesion Shear 
               
               
                   
                 Strength (lbs) 
               
             
          
           
               
                   
                   
                   
                 As 
                 After 30 
                 Bake 
               
               
                 Polymer 
                 Material 
                 Nail 
                 Ex- 
                 Min. 
                 Temp 
               
               
                 Composition 
                 Tested 
                 Temp 
                 truded 
                 Bake 
                 (° F.) 
               
               
                   
               
             
          
           
               
                 Polypropylene (PP) 
                 Current 
                 Cold 
                 6.0 
                 17.4 
                 375 
               
               
                   
                 material 
               
               
                 Modified PP- 
                 Amplify GR 
                 Cold 
                 6.5 
                 48.4 
                 300 
               
               
                 anhydride 
                 205 
                 Cold 
                 6.5 
                 44.4 
                 350 
               
               
                 Modified PP - 
                 Amplify GR 
                 Cold 
                 0.0 
                 39.9 
                 300 
               
               
                 anhydride 
               
               
                 HDPE/anhydride 
                 MSI 
                 Cold 
                 5.3 
                 3.6 
                 250 
               
               
                 blend 
                   
                 Cold 
                 5.3 
                 90.9 
                 350 
               
               
                   
                   
                 Hot 
                 64.0 
                 86.5 
                 350 
               
               
                 Modified PE- 
                 Bynel 
                 Cold 
                 6.7 
                 5.9 
                 250 
               
               
                 anhydride 
                   
                 Cold 
                 6.7 
                 49.4 
                 350 
               
               
                 12% vinyl acetate 
                 Elvax 
                 Cold 
                 4.5 
                 12.0 
                 225 
               
               
                 copolymer 
                   
                 Cold 
                 4.5 
                 15.9 
                 350 
               
               
                 EMMA Copolymer 
                 Suryin 9150 
                 Warm 
                 0.0 
                 51.2 
                 375 
               
               
                 (Zn) 
               
               
                 Modified PP- 
                 Tymor 
                 Cold 
                 8.4 
                 15.6 
                 350 
               
               
                 anhydride 
                 CP97X110 
                 Cold 
                 8.4 
                 88.0 
                 375 
               
               
                 Modified PP- 
                 Admer 
                 Cold 
                 4.6 
                 17.1 
                 300 
               
               
                 anhydride 
                 QF551A 
                 Cold 
                 4.6 
                 28.0 
                 350 
               
               
                   
                   
                 Hot 
                 71.0 
                 210.4 
                 350 
               
               
                 Blend 
                 75% Current 
                 Cold 
                 7.0 
                 7.3 
                 350 
               
               
                   
                 PP 
               
               
                   
               
             
          
         
       
     
     In Table 1, the plastic adhesion shear strength (in pounds, lbs.) was measured using a tensile testing device, by forcing the nails through a precisely sized hole in a direction parallel to the nail axis A 14  and measuring the force required to separate the nail  14  from the plastic  12 . The nails that were pre-heated prior to molding were heated to a temperature of about 500° F. to 550° F., after which the plastic was molded to the nails. For the post heat treatment, the nails were heated to the temperature shown for a period of about 30 minutes. 
     As can be seen from Table 1, the difference in plastic shear strength between the non-pre-heated nails and the preheated nails is quite significant. For the present maleic anhydride modified polypropylene, the difference is a factor of over 15 (71.0 lbs./4.6 lbs.) without post molding heat treatment. With post molding heat treatment, the shear strength increased by a factor of almost 3 over the non-post heat treated (pre-heated) nails. The plastic shear strength was shown to be about 71.0 lbs with pre-heating the nails prior to molding the plastic to the nails. In no case did a cold-applied plastic approach the shear strength of the pre-heated nail strips. 
     It was observed that nails strips formed in accordance with the present invention exhibited a very limited amount of debris compared to known plastic collations, principally because the plastic remained on the nail shank and penetrated the substrate (wood) with the nail. Moreover, it was found that the debris that was generated was in the form of a finer material (smaller sized particles) so there was less of a housekeeping issue with the debris that was generated. 
     Debris was collected from samples of nails to determine the “debris performance”, or reduction of debris generation of the present collation system. The amount of loose debris was measured by first weighing a given collated nail strip consisting of 10 nails. The starting weight of plastic was calculated by subtracting the weight of 10 uncollated nails from this amount. The test nail strip was then fired into a substrate (e.g., wood board) surrounded by an enclosure to facilitate the capture and collection of the loose debris. The collected loose debris was then weighed and divided by the original starting plastic amount to yield the percent loose debris for a particular plastic collation material. 
     Table 2, below, summarizes the results obtained with selected three of collating plastic materials (a non-adhesive polypropylene material, an adhesive material in accordance with the present invention that was formulated as a blend of 50 percent by weight polypropylene and 50 percent by weight of the maleic anhydride modified polypropylene, and a formulation of 100 percent of the maleic anhydride modified polypropylene). Firing tests were conducted in both pine and medium density fibreboard (MDF) substrates. 
     
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 DEBRIS GENERATED FROM VARIOUS 
               
               
                 PLASTIC NAIL COLLATIONS 
               
             
          
           
               
                   
                 % Loose Debris 
                 % Loose Debris 
               
               
                 Plastic collating material 
                 (Pine) 
                 (MDF) 
               
               
                   
               
             
          
           
               
                 Non-adhesive polypropylene 
                 86 
                 91 
               
               
                 Polypropylene/maleic anhydride 
                 17 
                 14 
               
               
                 modified polypropylene blend 
               
               
                 (50%/50% by weight) 
               
               
                 100% maleic anhydride modified 
                 0 
                 0 
               
               
                 polypropylene, 
               
               
                   
               
             
          
         
       
     
     It was also found that the nails carried the plastic into the wood and that the plastic was embedded in the wood with the nail. In fact, surprisingly, this increased the nails&#39; holding power in the wood. It is believed that this was due to the adhesive nature of the plastic as it embedded in the wood, in conjunction with the adhesion of the plastic to the nail. That is, it is believed that the plastic (adhesive) flowed into the wood structure and bonded with the wood structure, thus providing even greater holding power. 
     Table 3 below shows the results of evaluations that were conducted to compare the holding power or withdrawal strength of nails that were “fired” into wood from nail strips in accordance with the present invention to non-pre-heated polypropylene or control molded nail strip collations. The withdrawal strengths were measured as the force (in lbs/in of withdrawal) required to pull the nail from the wood. The values were normalized (e.g. calculated per inch of withdrawal) by dividing the force by the penetration depth. 
     
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 PENETRATION AND WITHDRAWAL STRENGTH OF NAILS 
               
               
                 CARRIED IN VARIOUS PLASTIC NAIL COLLATIONS 
               
             
          
           
               
                   
                   
                   
                   
                 Withdrawal 
                   
               
               
                   
                   
                   
                   
                 Strength 
                 Plastic 
               
               
                 Sample 
                 Standing 
                 Penetration 
                 Ultimate 
                 (lbs./in. of 
                 Collation 
               
               
                 No. 
                 Ht. (in) 
                 (in) 
                 (lbs) 
                 withdrawal) 
                 Material 
               
               
                   
               
             
          
           
               
                 1 
                 0.258 
                 2.432 
                 408.73 
                 168.06 
                 Tymor ™ 
               
               
                 2 
                 0.585 
                 2.415 
                 372.28 
                 154.14 
                 Tymor ™ 
               
               
                 3 
                 0.618 
                 2.382 
                 150.06 
                 63.00 
                 Control 
               
               
                 4 
                 0.616 
                 2.384 
                 150.93 
                 63.31 
                 Control 
               
               
                 5 
                 0.621 
                 2.379 
                 231.86 
                 97.46 
                 Admer ® 
               
               
                 6 
                 0.644 
                 2.356 
                 127.87 
                 54.27 
                 Control 
               
               
                   
               
             
          
         
       
     
     As can be seen from the data of Table 3, nail strips in accordance with the present invention exhibited considerably higher withdrawal strengths compared to non-adhered (control) nails. The control nails exhibited withdrawal strengths of about 54.3 to 63.3 lbs, whereas the preheated nails exhibited withdrawal strengths of about 97.5 to 168.1 lbs. In each case, the pre-heated nails required almost 54 percent greater force to withdraw or pull out the nails. At the same time, the nail penetration was essentially equal to that of the non-preheated nails. The Admer® and Tymor™ materials are both maleic anhydride modified polypropylene. 
     In the present nail strips  10 , the plastic is a uniform material that is molded over the nail shanks  16  and between the nails  14 . It will be appreciated that the plastic material can be a multi-part molding, in which discrete layers in the molding (collating) material are provided on the nails. In such a system, an adhesive can be applied or bonded to the nails onto which a layer of a material with desired characteristics (e.g., a stiffer or more rigid material or a more impact resistant material) is applied. Alternately, of course, a layered configuration can be achieved using a coextrusion of two or more plastics. 
     Another aspect of the present nail strip  10  is the shape or configuration of the molding around and between the nails  14 . That is, the shape of the collars  20  and the connecting portions  22 . In a present strip  10 , the collars  20  are formed as encircling elements that have a greater longitudinal or axial length at about a midpoint L 20M  between the connecting elements  22  (that is at about the midpoint of the circle inscribed by the nail), and dip to a smaller axial length at about the connecting portions L 20C . 
     The connecting portions  22  include a bridge  24  that extends from one collar  20   a  to the adjacent collar  20   b  and is about the height H 22  of the collar  20  at the collar  20 /connecting portion  22  juncture. The bridge  24  is a relatively long, thin element that in fact “bridges” the two adjacent collars  20   a ,  20   b . A rib  26  runs along the bridge  24  from one collar  20   a  to the next  20   b . The rib  26  is a cross-piece to the bridge  24  and has a low profile (e.g., is short) in the nail axial direction or along the length of the nail (i.e., has a low thickness t 26 ), but has a greater depth or width w 26  than the bridge  24 . As seen in  FIGS. 2 and 3 , the cross-section of the bridge  24  and rib  26  is cruciform-shaped, and with the  26  rib serving as the cross-piece, the rib  26  resides at about the middle of the bridge  24 . A cross-section taken through the nails  14  (see,  FIG. 3 ) that provides a top or bottom view of the connecting portion  22  shows that the rib  26  actually has a concave shape as it extends between the nails  14 . Both the bridge  24  and the rib  26  are formed having rounded ends, as indicated at  28 . 
     As will be appreciated by those skilled in the art, when a nail  14  is driven from the strip  10 , it is the nail  14 , the collar  20  and the connecting portion  22  between the driven nail  14  and the next adjacent nail  14   b  (see right-hand side of  FIG. 1 ) that are separated from the strip  10 . Desirably, this entire “assembly” is driven into the substrate, and it will be understood that it is desirable to drive as much of the assembly as possible into the wood to, among other things, reduce the amount of debris that is generated. 
     To effect separation of the connecting portion  22 , a notch  30  can be formed at the base or bottom  32  of the connecting portion  22  along a desired line of separation, or at the juncture of the connecting portion and the next adjacent nail. This provides a location at which the nail  14 , collar  20  and connecting portion  22 , as a unit, separate from the strip  10 . 
     The connecting portion  22  provides the necessary rigidity to the strip  10  that, in conjunction with the adhesive characteristics of the plastic, prevents corrugation of the strip  10 . Nevertheless, even with the increased adhesion and rigidity, that no significant increase in force is needed to drive the nail  14  and separate the nail  14  from the strip  10 . 
     In a present nail strip  10 , the upper and lower collations  12   a,b  have essentially equal dimensions. The collar  20  has a length L 20M , L 20C  of about 0.360 inches to 0.480 inches and a thickness t 20  of about 0.005 inches to 0.015. The bridge  24  has a length l 24  of about 0.280 inches to 0.420 inches and a thickness t 24  of about 0.006 inches to 0.014 inches and the rib  26  has a thickness t 26  of about 0.045 inches to 0.060 inches and a width w 26  of about 0.087 inches to 0.128 inches. It will be appreciated that because the rib  26  has a concave shape, the width w 26  varies along the length of the rib  26 . 
     Referring to  FIG. 4 , the collar  120  can be formed having a taper or a thinned region  122  at the collar portion  124  closest to the tip  34  of the nail  14  or at the leading end of the collar  120 . The collar  120  expands or thickens toward the trailing end  126 . It has been observed that this taper  122  facilitates penetration of the nail  14  and plastic collar portion  120  into the wood. The taper  122  is preferably formed at an angle β relative to the longitudinal axis A 14  of the nail  14 , of about 0.5 degree to about 5.0 degrees, and most preferably about 1.0 degrees. The taper  122  forms a wedge  128  that assists penetration of the nail  14  into the substrate and can further enhance the withdrawal resistance. It should, however, be recognized that the angle β cannot be too great in that the wedge  128  could serve to split the wood. 
     It has also been observed that the location of the collar  20  on the shank  16  contributes to increasing the penetration of the nail  14  into the wood. Specifically, it has been found that positioning the collar  20  closer to the tip  34  of the nail  14  results in increased nail penetration. It is believed that because the collar  20  (which is an interference to penetration) is positioned closer to the nail tip  34 , the greatest interference (that is as the collar  20  is entering the wood) is encountered while the impulse from the nail driving tool is high. Accordingly, the greatest resistance to penetration is overcome while the impulse from the tool is high, and, as such, penetration of the nail is greater when the collar  20  is positioned close to the nail tip  34  rather than farther back on the nail shank  16 , near to the nail head H. 
     An evaluation of the effect of the collar  20  position on the shank  16  was conducted. Using a nail  14  that was 3 inches long and 0.131 nominal diameter, with a collar length L 20M  of 0.5 inches and a thickness t 20  of about 0.020 inches and a collation material of maleic anhydride modified polypropylene (Admer®) and a pneumatic driving force of 90 psi, it was found that a nail  14  having a collar  20  positioned 2.25 inches from the tip  34  was driven (had a penetration of) 2.45 inches, a nail  14  having a collar  20  positioned 1.5 inches from the tip  34  was driven 2.75 inches, a nail  14  having a collar  20  positioned 0.5 inches from the tip  34  was driven 2.975 inches, and a bare nail  14  was driven 2.925 inches 
     It will be appreciated by those skilled in the art that the use of a forward positioned collar  20  (or more generally a forwardly positioned collation element or support) is not limited to use with a collated nail strip  10 . Rather, such an arrangement can be used with other strip formed fasteners and other strip-formed consumables. 
       FIGS. 5A and 5B  illustrate an embodiment  210  in which the ribs  226  are formed at an angle γ and γ′ relative to an axis A 210  of the strip  10  (as opposed to the ribs  26  in the embodiment of  FIG. 1  which are generally parallel to the axis A 10 ). 
       FIGS. 6 and 6A  illustrate an alternate embodiment of the plastic nail collation  310  in which an embossed pattern  324  is formed in the connecting portion  322  of the strip  310 , rather than the bridge  24  and rib  26  configuration (of  FIGS. 1-5 ). In the embossed pattern  324  embodiment, a pattern of ribs  326  is formed in the connecting portion  322  that can extend in one or both directions relative to a plane P 322  that is defined by the connecting  322  portion extending between the collars  320  (e.g., into or out of or both into and out of the plane P 322  defined by the connecting portion  322  and the adjacent nails  14   a,b ). A cross-section of a one-directional embossing  324  is illustrated in  FIG. 6A . The embossing  324  serves to provide a three-dimensional structure, much like the bridges  24  and ribs  26 , to enhance the rigidity of the strip  310 . In addition, it is anticipated that the embossing  324  can provide the necessary rigidity and predictability in separation while at the same time, reducing the amount of material needed to form the strip  310 . A rib  325  can be used with the embossed collation embodiment  310 , as well. The embossing can also be formed in the collar. 
     It will be appreciated by those skilled in the art from a review of the drawings that the present collation can be used with a coiled nail collation (see,  FIG. 1B , which shows a coiled nail strip  10 ′) as well. In such an arrangement, the collation is formed with a bridge connecting the collar portions, however, a reinforcing or stiffening element (e.g., rib) is not used so that the strip can be coiled. In such an arrangement, the collations can be such as those shown in  FIGS. 11A and 11E , in which the connecting portions  822 ,  1822  include bridges  824 ,  1824 , but no ribs. This permits the flexing of the collations as necessary to roll or coil the collation. 
     Referring to  FIGS. 7A and 7B , it has been found that the amount of debris that is generated when the nail  14  is driven from the strip  10  is reduced when the nail connecting portion  22  is separated as close as possible to the next trailing nail  14   b  ( FIG. 7B ). Comparing  FIGS. 7A and 7B , it can be seen that debris is reduced when the driven nail  14   a  is separated from the strip  10  with as much of the trailing connecting portion  22   b  as is practical. This is to reduce the opportunity for the downward moving head H 14a  of the driven nail  14   a  to contact and tear (actually, a better description is strip) the connecting portion  22  from the connecting portion  22  that remains. It will be appreciated that if the connecting portion is  22  separated as far from the driven nail  14   a  as possible, then little to nothing will remain for the nail head H 14a  to contact and tear from the connecting portion  22  (see for example  FIG. 7B ). It has been found that the portion of the connecting portion  22  that remains connected to the driven nail  14   a , that is the trailing connecting portions  22   b , are sufficiently strong to remain intact and attached to the nail  14   a  as the nail  14   a  is driven into the substrate. 
     In order to provide this selectively or preferentially located separation region, a number of configurations have been examined. One such configuration is to include the notch  30  as seen in the embodiment  10  of  FIG. 1  and as seen in  FIGS. 8A and 8B . To effect separation of the connecting portion  22  as close to the trailing nail  14   b  as possible, the notch  30  should be positioned as close to the trailing nail  14   b  as possible. 
     Essentially, the strip  10  is configured with a weakened region so that separation is influenced or encouraged at a desired location. However, it should be noted that it is desirable to have the remaining portion of the connecting portion  22  remain intact as the nail  14   a  is driven into the substrate to reduce the debris generated. Accordingly, as seen in  FIG. 8B , the notch  30  can be configured with a semi-circular notch wall  30   a , and may also include a lower notch  30   b  to further influence separation location. 
     Another embodiment of the strip  410  can be configured so that separation is influenced by selectively thinning areas at which separation is desired. For example, in  FIG. 9A , the bridge  424  is thinned at the trailing nail  14   b  collar  420  (the desired separation location) by forming a small radius transition (indicated generally at  423 ) between the bridge  424  and the collar  420   b  or the trailing nail  14   b  and maintaining a larger radius transition (indicated generally at  425 ) between the bridge  424  and the leading nail  14   a  (the nail to be driven) collar  420   a . The smaller radius transition is about 0.015 to 0.025 inches, whereas the larger transition radius is about 0.050 to 0.060 inches. 
     The larger radius transition  425  results in more material being present at the leading nail collar  420   a /bridge  424  transition. This in turn influences separation to occur closer to the transition between the bridge  424  and the trailing nail  14   b  (the smaller radius area with less material). In  FIG. 9A  the nails  14   a ,  14   b  and the connecting portion  422  are shown (with the nail heads H 14a  and H 14b  shown in phantom lines) to illustrate that the head H 14a  of the leading nail  14   a  is at about the same location as, e.g., overlying, the thinned bridge region  423 . As such, the connecting portion  422  (that is, the bridge  424  and rib  426 ) is not struck by (or minimally struck by) the nail head H 14a  as it is driven from the strip  410 . This, as will be appreciated by those skilled in the art, will reduce the amount of debris generated. 
     Another embodiment  510  is illustrated in  FIG. 9B , which shows a variation on the large radius/small radius configuration in which the axes A 14a , A 14b  of the nails  14   a ,  14   b  are offset (or eccentric) relative to the axes of the collars  520   a ,  520   b . In this embodiment, the nails are offset to establish a thinner collar region at the smaller radius juncture. This further influences or encourages separation as close as possible to that juncture (as indicated at  523 ). 
     In still another embodiment illustrated in  FIGS. 9C and 9D , the thinned region  1423  is provide at the trailing nail  14   b  transition by forming a small radius region (about 0.010 to 0.018 inches compared to the leading nail radius region  1425  of about 0.060 inches) that defines a neck region  1428 . The neck can have a thickness t 1428  of, for example, about 0.0070 inches. 
     Other embodiments of the nail collation  610 ,  710 , respectively, are seen in  FIGS. 10A and 10B , in which the connecting portion  622  includes a thin bridge  624  with a relatively stiff rib  626  extending between the collar portions  620  ( FIG. 10A ) or even no bridge with a relatively stiff rib  726  extending between the collar portions  720  ( FIG. 10B ). The rib  726  can be dimensioned so that the width w 726  is greater than the width w 720  of the nail  14  and collar  720  (that is, measure across the collar  720 ). 
     To further enhance the ability of the nail to penetrate the substrate, while maintaining a high level of confidence of the structural integrity of the plastic collations, the various structural portions of the connecting portion  22  can be tapered. As seen in  FIG. 11A , the connecting portion  822  can be formed with a bridge  824  that tapers outwardly from the leading edge  827  (the edge to first enter the substrate) to the trailing edge  829 . As seen in  FIG. 11E , the tapered connecting portion  1822  can be inverted relative to that shown in  FIG. 11A . It is anticipated that both of the rib-less configurations, those shown in  FIGS. 11A and 11E  will be particularly well suited for coiled applications ( FIG. 1B ). Alternatively, as illustrated in  FIG. 11B , the rib  926  can be tapered with straight bridge section  924 , or, with a tapered bridge section  1024  ( FIG. 11C ). The rib  1226  can be tapered on both the upper and lower ends, preferably at an angle γ of about 45 degrees, with or without a tapered bridge  1224  ( FIG. 11D ), to provide increased stiffness and less debris. The rib  1226  can have a thickness t 1226  of about 0.070 inches and the bridge  1224  can have a thickness t 1224  of about 0.013. 
     As seen in  FIG. 12 , another way to reduce the amount of debris generated is to reduce the size (width) of the lower collation  1112   b . In the illustrated embodiment, the lower collation  1112   b  width w 1112b  is about ½ of the width w 1112a  of the upper collation  1112   a.    
       FIGS. 13A and 13B  illustrate an embodiment  1310  of the strip in which the nails  1314   a,b  include rings or serration-like formations  1320  that extend outwardly from the nail shanks  1316 , beyond an outer periphery of the shank  1316 . The formations  1320  facilitate creating an enlarged opening in the substrate to ease penetration of the collation material  1322  into the substrate, without creating debris. Essentially, the rings or serration-like formations  1320  tend to further expand the opening the substrate to allow for lower-stress penetration of the collation material  1322 . 
       FIGS. 14A and 14B  illustrate yet another embodiment  1410  in which the nail  1414  have deformations  1420  in the shanks  1416  under the collation material  1422 . The deformations can be formed as rings, abraded or roughened regions, or the like, to increase adhesion of the material  1422  and the shank  1416 . 
       FIGS. 15A and 15B  illustrate still another embodiment of the nail collation  1510 . In this embodiment, the rib  1526  is formed at or near the top of the bridge  1524 . In a present embodiment, the rib  1526  has a tapered shape, narrowing toward the tip  34  of the nail  14   a . Again, this promotes penetration of the entirety of the nail  14   a  and the collar  1520  (and portions of the bridge  1524  and rib  1526 , as appropriate) into the wood, to further minimize generation of debris. It has been found that following molding of the collation  1512 , the rib  1526  tends to cure into the tapered shape as well. It will be appreciated that the shape of the rib  1526  can be as shown (a diamond-like shape) or any of a side variety of shapes, including but not limited to those illustrated herein. The bridge  1524  and rib  1526  are formed integral with the collar  1520  (the entirety of the collation system  1512  is formed as an integral system). The other features described above, such as the weakened or selectively weakened regions, thinned areas and the like can also be incorporated into this embodiment. 
     In each of these embodiments, the collation is configured so as to minimize or eliminate corrugation while at the same time, to reduce the amount of debris generated when the nail  14   a  is driven into the substrate. 
     All patents referred to herein, are incorporated herein by reference, whether or not specifically done so within the text of this disclosure. 
     In the present disclosure, the words “a” or “an” are to be taken to include both the singular and the plural. Conversely, any reference to plural items shall, where appropriate, include the singular. 
     From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention. It is to be understood that no limitation with respect to the specific embodiments illustrated is intended or should be inferred. The disclosure is intended to cover by the appended claims all such modifications as fall within the scope of the claims.

Technology Classification (CPC): 5