Patent Abstract:
An upholstery tack strip includes a metal ribbon and a thermoplastic sleeve covering at least a portion of the ribbon. The sleeve includes at least one, and possibly a pair of, lengthwise removed strip section(s) so as to expose a corresponding lengthwise surface of the metal ribbon. The metal ribbon integrally includes nail sections which protrude outwardly from said tack strip. At least one, and preferably both, lateral edges of the metal ribbon are knurled or serrated so as to assist in anchoring the ribbon to the sleeve.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional application of application Ser. No. 10/808,506, filed Mar. 25, 2004 (now U.S. Pat. No. 7,200,916), which is a divisional application of application Ser. No. 10/428,834 filed May 5, 2003 (now U.S. Pat. No. 6,989,186), which is in turn a continuation-in-part of application Ser. No. 10/180,102, filed Jun. 27, 2002 (now U.S. Pat. No. 6,647,610), the entire content of each being hereby incorporated by reference in this application. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to the field of upholstery fabric tack strips and methods of making the same, especially tack strips that are used to attach upholstery fabric to an underlying furniture frame member. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     Conventional upholstery tack strips are made from flat metal (e.g., metal) ribbons by a punch-press operation. Specifically, generally triangularly-shaped nails are formed by punching out correspondingly shaped, partially cut-out sections from the metal ribbon at spaced-apart locations along the ribbon&#39;s length and then bending the sections so each is at substantially a right angle relative to the ribbon stock. Thus, the nails remain unitarily attached to the metal ribbon, but project outwardly therefrom. 
     In use, the metal from which conventional tack strips are made can physically mar and/or abrade the upholstery fabric. For example, the ribbon, if formed from metal, may rust over time which might in turn visibly discolor the fabric. Furthermore, the edges of the metal tack strip may abrade or cut the upholstery fabric. In order to prevent such problems, it has been conventional practice to provide upholstery tack strips with a separate C-shaped plastic sleeve which slides over the tack strip along its length. The plastic sleeve, however, is itself problematic in that it involves a separate manufacturing step to slideably mate it with the tack strip. Furthermore, unless some means are provided to restrict relative lengthwise movement between the metal tack strip and the sleeve, the latter can become separated from the former during use and/or installation. 
     In our recently issued U.S. Pat. No. 6,537,646 B2 (the entire content of which is expressly incorporated hereinto by reference), novel upholstery tack strips are provided which include a thermoplastic sleeve and a metal ribbon embedded within the sleeve. The sleeve itself includes a plurality of removed material sections forming opposed pairs of sleeve windows, while the metal ribbon integrally includes nail sections which protrude outwardly from the tack strip through respective ones of the sleeve windows. Most preferably, the sleeve is extrusion-coated onto the metal ribbon stock using a cross-head die with a screw extruder. The thus-coated metal strip preform may then be transferred to downstream fabrication operations whereby the sleeve windows and nail portions are formed. Since the nail portions protrude outwardly from the tack strip through the sleeve windows, relative lengthwise slippage between the metal ribbon stock and the sleeve is prevented. 
     The present invention is directed specifically toward improvements to the upholstery tack strips of the type generally disclosed in our above-cited U.S. Pat. No. 6,537,646 B2. More specifically, according to the present invention upholstery tack strips include a metal ribbon and a thermoplastic sleeve covering at least a portion of the ribbon. The sleeve includes at least one lengthwise removed strip section so as to expose a corresponding lengthwise surface of the metal ribbon. Most preferably, at least one (and advantageously both) edges of the metal ribbon are knurled or serrated so as to present a roughened surface to the sleeve and thereby anchor the metal ribbon to the sleeve and thereby assist in maintaining the relative positioning of the sleeve and metal ribbon. An adhesive may optionally alternatively or additionally be applied to the metal ribbon so as to also assist in anchoring the thermoplastic sleeve thereto. The metal ribbon integrally includes nail sections which protrude outwardly from said tack strip. 
     These and other aspects and advantages will become more apparent after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
       Reference will hereinafter be made to the accompanying drawings, wherein like reference numerals throughout the various FIGURES denote like structural elements, and wherein; 
         FIG. 1  is a schematic view showing a possible manufacturing sequence in accordance with the present invention; 
         FIG. 2  is a top perspective view showing a representative length of an upholstery tack strip in accordance with the present invention; and 
         FIG. 3  is a bottom perspective view showing a representative length of an upholstery tack strip in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Accompanying  FIG. 1  depicts one possible manufacturing sequence for making the upholstery tack strip of the present invention. In this regard, a roll of metal strip or ribbon stock  10  may be fed to and through the cross-head die  12   a  associated with screw extruder  12 . Prior to being fed through the cross-head die  12   a , however, the ribbon  10  is preferably pulled through a knurling tool  12   b  which may include, for example, a pair of opposed knurled rollers acting on at least one, and preferably both, of the lateral edges of the metal ribbon  10  so as to knurl the same as shown by reference numeral  10   a  in  FIGS. 2-3  below. In this manner, the knurled edges  10   a  present a roughened surface to the thermoplastic sleeve applied via the cross-head die  12   a  so as to assist in anchoring the ribbon  10  thereto. The ribbon  10  may optionally alternatively or additionally be pulled through an adhesive applicator  12   c  which serves to apply an adhesive material onto the ribbon  10  and thereby assist in anchoring the thermoplastic sleeve thereto which will be applied via the cross-head die  12   a.    
     As is well known, thermoplastic pellets may be fed into the hopper (not shown) of the screw extruder  12 . The extruder  12  thus forms a molten stream of the thermoplastic material which is fed into the cross-head die  12   a  and applies a coating over the entire surfaces of metal ribbon  10 . The coated ribbon (now designated by numeral  13  in  FIG. 1 ) then enters a water quench bath  14 . Upon cooling, therefore, the thermoplastic material is thereby coated onto the metal ribbon stock  12  so as to form a composite strip preform  16 . Specifically, the preform  16  includes a core of the metal ribbon stock  10  which is embedded within, and thus coated entirely by, a sleeve formed of solidified thermoplastic material (i.e., the solidified residue of the thermoplastic material applied in its molten state by the cross-head die  12   a ). 
     Virtually any thermoplastic material may be employed in accordance with the present invention. Preferred thermoplastic materials include polyolefins (e.g., polyethylene and polypropylene), nylons, polyesters, polyvinyl chlorides and the like. 
     The composite strip preform  16  passes through an air dryer  18  which serves to remove water from the surface of the perform  16  prior to being directed to a cutter  20   a . The perform is pulled from the roll of stock  10  through the cross-head die  12   a , quench bath  14  air dryer  18  and cutter  20   a  via an opposed set of pull rolls  22 - 1 ,  22 - 2 . The cutter  20   a  serves to cut a substantially centrally located longitudinally oriented strip section  16   a  of the thermoplastic coating, which strip  16   a  is then removed from the upper and lower surfaces, respectively, of the metal stock  10  via roller pairs  24   a . The removed thermoplastic strip  16   a  is then collected in waste bin  26   a  for recycling to the extruder  12  where it can be re-melted and combined with virgin thermoplastic material so as to coat the stock  10  in the cross-head die as was explained previously. 
     Optionally, a cutter  20   b , rollers  24   b  and waste bin  26   b  may be provided so as to remove a strip  16   b  from the opposite surface of the composite strip  16 . If such a strip  16   b  is removed, then a pair of longitudinally extending exposed surface regions of the metal ribbon  10  will result. That is, with removal of both strips  16   a ,  16   b , only the side edge regions of the stock  10  will be covered with the thermoplastic material forming generally U-shaped edge protectors. Most preferably, however, as shown in  FIGS. 2 and 3 , only the bottom strip  16   a  is removed thereby exposing a lengthwise extending section  10   b  of the lower surface of the metal strip  10  (see  FIG. 3 ). 
     The edge-coated perform (now designated by reference numeral  16 - 1  in  FIG. 1 ) may subsequently be formed into a roll  30  and then used as a feed for a coining/punching operation  32  as shown in  FIG. 1 . Alternatively, the composite strip preform  16  may be fed continuously from the cross-head die  12   a , through the cutter  20   a  and then to the coining/punching operation  32 . 
     During the coining/punching operation  32 , nail-forming punch dies are brought to bear directly against the upper and lower surfaces metal strip  10 . Thus, as with conventional tack strips, therefore, the coining/punching operation  32  serves to punch out generally triangularly shaped nails  10 - 1  from the metal ribbon  10  and bend them at substantially right angles thereto as shown in accompanying  FIGS. 2 and 3 . The finished tack strip TS in accordance with the present invention may then be cut into desired lengths (e.g., from about 3 inches in length up to about 48 inches in length), packaged and shipped in operation  36  as shown in  FIG. 1 . 
     As can be appreciated, removal of the strip  16   a  will form a pair of opposed edge protectors  16   c ,  16   d  as an integral extruded member which covers the lateral edges of the metal ribbon stock  10 . That is, the removal of the strip  16   a  to expose the lower surface of ribbon  10  will provide the generally U-shaped edge protectors  16   c ,  16   d  which are joined integrally one to another along the upper surface of the ribbon  10 . As such, the sleeve and the edge protectors  16   c ,  16   d  do not need to be installed during a separate operation. As noted previously, the knurled edges  10   a  of the ribbon  10  present a roughed surface to the edge protectors  16   c ,  16   d  thereby anchoring the ribbon  10  thereto. However, if desired, an adhesive may be alternatively or additionally be applied to the edges  10   a  of the ribbon stock  10  prior to being drawn through the cross-head die  12   a  so that the resulting edge protectors  16   c ,  16   d  remain physically in place during handling. Also, in the embodiment depicted in  FIGS. 2 and 3  wherein only strip  16   a  is removed, there will also exist generally triangular sleeve remnants  16 - 2  integrally attached at their bases to the sleeve. Such remnants  16 - 2  will thus extend downwardly through the hole remaining in the ribbon  10  by virtue of the nails  10 - 1  being formed in the coining/punching operation  32  and thereby also assist to minimize lateral slippage of the sleeve relative to the ribbon  10 . 
     Thus, while the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Technology Classification (CPC): 8