Abstract:
A frame includes longitudinal members secured to one another. The longitudinal members support a spline that is normally open in a first position to provide a cavity. A fabric, such a mesh screen, is arranged over the frame so that the perimeter of the screen is received within the cavities of the longitudinal members. A movable platen is actuated to engage the spline. The splines are forced into the cavities to a second position in which the perimeter of the screen is pinched between the splines and the longitudinal members. A radius nose of the splines is retained in a channel of the longitudinal members securing the screen without tearing it when under load.

Description:
[0001]     This application claims priority to provisional application No. 60/885,426 filed on Jan. 18, 2007. This application is also a continuation-in-part of application Ser. No. 11/233,640 filed on Sep. 23, 2005, which claims priority to provisional application No. 60/615,794 filed on Oct. 4, 2004, and a continuation-in-part of application Ser. No. 10/825,525 filed on Apr. 15, 2004, which claims the benefit to provisional application Nos. 60/485,579 and 60/492,698 respectively filed on Jul. 9 and Aug. 6, 2003. 
     
    
     BACKGROUND  
       [0002]     This application relates to a longitudinal frame member and spline for use in attaching fabric, for example, to a frame.  
         [0003]     Frames used for windows, doors and office furniture, such a cubical dividers, have fabric attached to a frame in some fashion. Other applications include ceiling panels, air/water filter panels, and acoustic tiles. In the example of window frames and doors using screens, typically the frame includes longitudinal frame members having channels to which the screen is secured. The longitudinal members are joined to one another in some fashion to provide the frame. During assembly, the screen is positioned over the frame and a rubber spline having a generally circular cross section is inserted into the channels thereby retaining the screen between the spline and longitudinal frame members. Other approaches have been used to secure the screen to the frame. Typically, a separate retaining member is pressed or snapped into the frame, securing the screen between the frame and retaining member. However, manipulating and inserting a separate retaining member, like a rubber or plastic spline into the frame members while controlling the woven fabric, is labor intensive and costly.  
         [0004]     Installation of fabric using the spline arrangement described above or other manners of screen attachment are typically labor intensive and costly. In the example of the splines described above, a special tool having rollers must be run along the length of longitudinal member. Moreover, the frame tends to “hourglass” as a result of the screen assembly process. Pre-bowing the frame members and blocking of the assembled frame for squareness is typically used to prevent this undesired result, which adds cost to assembly.  
         [0005]     Another approach for securing screens has been to use a hinged retaining member integral with and movable relative to the frame, as disclosed in U.S. Pat. No. 3,379,237. The arrangement disclosed in the &#39;237 patent has at least two problems. First, the frame is not structurally stable such that it will deflect and permit the retaining member to open, thus releasing the screen. Second, the retaining member does not keep sufficient force on the screen to maintain the screen in tension. Third, there is a sharp edge on the retaining member that is the primary and only point of engagement with the screen, which will tend to tear the screen when force is applied to it.  
         [0006]     Window and door screens must pass an industry “push out” test. One industry standard requires that the screen be held through the longitudinal frame members for at least forty pounds of applied force. The standard can sometimes be difficult to meet using rubber or plastic splines.  
         [0007]     What is needed is an improved frame that requires less labor and cost to manufacture while meeting or exceeding the present industry standard for “push out” and improving the hour glass specifications.  
         [0008]     These and other features of the disclosure can be best understood from the following specification and drawings, the following of which is a brief description.  
       SUMMARY  
       [0009]     An example frame of the disclosure includes longitudinal members secured to one another, for example by using corner locks, to form the frame. The longitudinal members support an integral spline that is normally open prior to assembly to expose a cavity that receives a fabric. A fabric, such a mesh screen, is arranged over the frame so that the perimeter of the screen is received within the cavities of the longitudinal members.  
         [0010]     In one example, the frame is retained on a fixed platen by stops. A movable platen is actuated to engage the spline. The splines are forced into the cavities or channels to a closed position in which the perimeter of the screen is pinched between a nose of the spline and the longitudinal members. The nose provides three engagement features, in one example, that ensure that screen is securely retained without tearing it. The first engagement feature is provided by a curved portion of the nose that engages and pushes the screen down into the cavity as the spline is moved from the open to the closed position. The second engagement features is provided by a corner of the nose that pinches the screen against a base wall of the channel. The third engagement feature is provided by a ridge that extends from the base wall to support the perimeter of the screen so that it wraps about the corner thereby enhancing retention. The spline profile is designed to deflect about a fulcrum hinge point away from the engagement features of the surrounding frame to prevent the frame from distorting during assembly.  
         [0011]     The spline is generally S-shaped in one example. The spline may be integral with the longitudinal member or separately secured to the longitudinal member, for example, by snapping or sliding the spline into a recess in the longitudinal member.  
         [0012]     Accordingly, the disclosed frame requires less labor and cost to manufacture while meeting or exceeding the present industry standard for “push out.” Further, the frame members do not require pre-bowing or blocking during the assembly process. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1A  is an exploded view of a frame including longitudinal frame members with square ends.  
         [0014]      FIG. 1B  is a perspective view of the frame of  FIG. 1A  shown assembled.  
         [0015]      FIG. 2A  is an exploded view of a frame including longitudinal frame members with mitered ends.  
         [0016]      FIG. 2B  is a perspective view of the frame of  FIG. 2A  shown assembled.  
         [0017]      FIG. 3A  is a top elevational view of an example manufacturing process for the frame.  
         [0018]      FIG. 3B  is a cross-sectional view of the frame having a screen installed.  
         [0019]      FIG. 4  is a perspective view of another example manufacturing process for the frame.  
         [0020]      FIG. 5  is a perspective view of barbs used to improve retention of the screen.  
         [0021]      FIG. 6  is a cross-sectional view of another example of the longitudinal frame member.  
         [0022]      FIG. 7  is a cross-sectional view of a longitudinal frame member similar to  FIG. 6  with a ridge.  
         [0023]      FIG. 8  is a cross-sectional view of a longitudinal frame member similar to  FIG. 3B  with a ridge.  
         [0024]      FIG. 9  is a cross-sectional view of a longitudinal frame member similar to  FIG. 8  with a spline overmolded to a tubular portion of the frame member.  
         [0025]      FIG. 10  is a cross-sectional view of the longitudinal frame member wrapped in a decorative fabric.  
         [0026]      FIG. 11A  is a perspective view of another example longitudinal frame member.  
         [0027]      FIG. 11B  is a cross-sectional view of the longitudinal frame member shown in  FIG. 11A  with a screen prior to assembly.  
         [0028]      FIG. 11C  is a cross-sectional view of the longitudinal frame member shown in  FIG. 11B  with the spline in a closed or bottomed position.  
         [0029]      FIG. 12  is a perspective view of the longitudinal frame member shown in  FIG. 11A  in a transitional or interference position.  
         [0030]      FIG. 13  is a perspective view of the longitudinal frame member shown in  FIG. 11C  in the closed or bottomed position, but without the screen.  
         [0031]      FIG. 14A  is a cross-sectional view of a longitudinal frame member with a bi-laminate plastic extrusion spline.  
         [0032]      FIG. 14B  is a cross-sectional view of a longitudinal frame member shown in  FIG. 14A  with the spline in a closed position retaining a screen.  
         [0033]      FIG. 15  is an enlarged cross-sectional view of another example construction of an end of the longitudinal frame member.  
     
    
     DETAILED DESCRIPTION  
       [0034]     An example longitudinal frame member  10  is shown in the Figures. Like numerals are used to refer to like elements between some Figures.  
         [0035]     Referring to  FIGS. 1A-2B , a rigid frame is constructed from structure including the longitudinal frame member  10 , which provides a tubular portion  12 , for example, and a spline  14 . The tubular portion  12  is quadrangular in shape in one example. The longitudinal frame member  10  provides a channel  26  that receives a portion of the spline  14  to securely retain the screen to the member  10 , which will be discussed in more detail below.  
         [0036]     The example member  10  shown in  FIGS. 1A-3B  is roll formed out of a sheet of metal so that the spline  14  is formed integrally with the longitudinal frame member  10 . In other examples, the longitudinal frame member  10  and spline  14  are extruded plastic, aluminum or fiberglass ( FIGS. 11A-13 ). In other examples, the spline  14  can be separately secured to the longitudinal frame member  10 , which may be wood or aluminum, to form an integrated structure ( FIG. 6 ), or the plastic spline  14  can be extrused onto the member  10  ( FIGS. 14A-15 ).  
         [0037]     For roll-formed members, the member  10  includes a first edge  16  provided on the spline  14  and a second edge  18  provided on the tubular portion  12 , best seen in  FIG. 4 . The integral tubular and spline portions  12  and  14  are secured to provide a desired cross-sectional shape by forming a flange  20 , which is shown in  FIGS. 1A and 4 . The flange  20  may include a series of indentations  21  formed by a roller to further secure the metal in the desired shape, best shown in  FIG. 1A . In one example, the member  10  is constructed from a suitable metal that is either roll formed and/or extruded. A plastic or other material may also be used.  
         [0038]     Opposite the flange  20  is a wall  22  having a slot  24  for receiving a corner lock  28 . The corner lock  28  includes first and second legs  30  and  32 . The first leg  30  is received in the tubular portion  12 , and the leg  32  extends from the slot  24 .  
         [0039]     The arrangement shown in  FIGS. 1A and 1B  depicts longitudinal frame members  10  that have square ends. In such an arrangement, it may be desirable to provide an end cap  29  on the corner lock  28 . Referring to  FIGS. 2A and 2B , the longitudinal frame members  10  include mitered ends  31  that may provide for a more aesthetic mitered joint M and also eliminate the need for slot  24 .  
         [0040]     Referring to  FIG. 3A , a machine  34  is disclosed for securing a fabric  44 , such as screen, to be the longitudinal frame members  10 . It should be understood that “fabric” is intended to include woven and non-woven materials, which also includes flexible membranes. The members  10  are assembled using the corner lock  28 , for example, or any other suitable method of attachment, to provide a frame  42 . The frame  42  is arranged on a fixed platen  36  having fixed stops  38 . Movable stops  40  are actuated to secure the frame  42  against the fixed stops  38 . The arrangement of stops  38  and  40  enables any size frame  42  to be accommodated on the machine  34 .  
         [0041]     Another example assembly process is shown in  FIG. 4 . The frame  42  is supported on a movable surface  39 . The surface  39  and frame  42  are passed between opposing rollers  41 , which closes the spline  14  over the fabric  44  thus securely retaining the fabric  44  relative to the tubular portion  12 .  
         [0042]     According to one example method of assembly, referring to  FIG. 3B , the fabric  44  is positioned on top of the frame  42  with the spline  14  in a first position P 1 . A cavity or channel  55  is provided between the spline  14  and the tubular portion  12  in the first position P 1  for receiving the fabric  44 . The spline portion includes a nose  46  having the first edge  16 . The nose  46  extends to an arch  48  having an adjoining spring portion  49  opposite the nose  46 . In the example shown in  FIG. 3B , the spring portion  49  is integral with the tubular portion  12 . In the example embodiment, the nose  46  has a smaller radius than the gradual radius of the arch  48 . The spring portion  49  has a smaller radius than the nose  46 . The spring portion  49  biases the spline  14  upward and away from the tubular portion  12  to an open position.  
         [0043]     The machine  34  includes a movable platen  50  having a flat profile  52 . By utilizing a flat profile  52 , the tooling costs are drastically reduced since a platen of particular profile requiring machining is not required, and alignment issues between the movable platen  50  and frame  42  are eliminated.  
         [0044]     The tubular portion  12 , or base portion, is generally quadrangular in one example and includes a base wall  58  that provides a bottom surface of the channel  26 . The base wall  58  extends between and interconnects spaced apart first and second outer walls  59 ,  61 , in one example. In the example shown in  FIG. 3B , a bottom wall  57  interconnects the first and second outer walls  59 ,  61  to provide an enclosed space, which receives the legs  30 ,  32  of the corner locks  28 . The example shown in  FIG. 6  depicts a bottom wall  57  with a gap that exposes the space provided by the tubular portion  12 . The tubular member provides structural stability to the spline  14  so that it is not forced open once the fabric  44  has been installed. The first outer wall  59  extends outwardly away from the base wall  58  to support the spring portion  49 . The second outer wall  61  extends outwardly away from the base wall  58  to provide the flange  53 .  
         [0045]     The movable platen  50  is moved downward into engagement with the spline  14  moving the spline  14  from the first or open position PI (see also  FIGS. 11A and 11B ) to a second position P 2  (see also  FIG. 12 ), which forces the perimeter of the fabric  44  into the channel  26 . The curved portion of the nose  46  provided a first engagement feature that pinches the fabric  44  against a flange  53  to stretch the fabric. In one example, the edge of the flange  53  is rounded to prevent the fabric  44  from tearing as the nose  46  pushes the fabric  44  into the channel  26 . The arch  48  extends above the flange  53  that, in part, provides the channel  26  along with a surface  58  of the tubular portion  12 . The movable platen  50  continues to move downward moving the spline  14  from the second position P 2  to the third or closed position P 3  (see also  FIGS. 11C and 13 ). In the position P 3 , the nose  46  is forced further into the channel  26  securely retaining the perimeter of the fabric  44 . The radius nose  46  prevents the fabric  44  from tearing as force is applied to it. The flexible spline  14  deflects without yielding.  
         [0046]     The nose  46  has a sharp corner  56 , for example, on the first edge  16  that pinches the fabric  44  to retain the perimeter of the screen between the corner  56  and the surface of the base wall  58 , thus providing a second engagement feature. The corner  56  not likely to tear the fabric  44  as force is applied to it since the fabric at this location will experience a smaller force that at the first engagement feature. In the third position P 3 , the arch  48  has a larger radius than it did in first position P 1 , and the nose  46  has smaller radius than it did in the first position P 1 . The deflected spline  14  applies sufficient retaining force on the fabric  44  to prevent “push-out” of the fabric. The fabric  44  begins to tear, which occurs at around 125 pounds of applied force for typical insect screen materials, without it pulling out of the channel  26 .  
         [0047]     To further improve retention of the fabric  44 , a third engagement features, such as barbs  54 , may extend upward from the base wall  58  into the channel  26 , as is show in  FIG. 5 . The fabric  44  at the third engagement feature experiences an even smaller force than at the second engagement feature.  
         [0048]      FIG. 6  depicts another example longitudinal frame member  60 , which is extruded. The longitudinal frame member  60  includes a tubular portion  62  having a separate spline portion  72 . The tubular portion  62  provides a recess  64  having a protrusion  66  and fulcrum  68 . A spring portion  80  of the spline portion  72  is inserted into the recess  64 , and an edge  82  is retained by the protrusion  66 . The spring portion  80  acts against the fulcrum  68  when moving between the first, second and third positions P 1 , P 2  and P 3 . Similar to the embodiment described in  FIG. 4 , the spline portion  72  includes an arch  74  and nose  76 . The nose  76  is forced into the channel  78  by the movable platen  50 . The fabric  44  is retained between the nose  76  and surface  70 .  
         [0049]     Referring to  FIG. 7 , the spring portion  80  is retained in the recess  64 . The arch  74  may or may not include an apex, depending upon the geometry of the spline  14  and tubular portion  12 . The fulcrum  68  extends from the surface  70 . A ridge  86 , which provides a third engagement feature, also extends from the surface  70  to lift an edge portion  88  of the fabric  44  away from the surface to better ensure that the corner  56  engages and holds the screen  44 . The ridge  86  is also shown for roll-formed longitudinal frame members  10  in  FIG. 8 , and at  186  and  210  respectively in  FIGS. 11B and 14B .  
         [0050]     In another example, the spline  14  can be adhered to the tubular portion  12  by any suitable process, such as by laminating or over-molding, as shown in  FIG. 9 .  
         [0051]     The example longitudinal frame member  10  permits easy replacement of the screen. The spline  14  may be “zippered” open and the damaged screen removed and replaced. With the new screen positioned as desired, the spline  14  can be manually forced back into the channel  26  using a block of wood and hammer or a roller, for example.  
         [0052]      FIG. 10  depicts the inventive longitudinal frame member  10  for furniture or other applications in which it is desirable to conceal the tubular member  12 . A decorative fabric  94  is wrapped around a side  92  other than the side that supports the spline  14 . In another example, the member  10  is a sanding block, and the fabric  94  is an abrasive material such as sandpaper or sanding screen. For a sanding block, a spline  14  is provided at each end of the block to retain opposing ends of the sandpaper.  
         [0053]     Referring to  FIGS. 14A and 14B , the frame  190  includes a frame member  192  having the channel  194 . The frame member  192  includes a flange portion having a flange  204  connected to the tubular portion of the frame member  192  by a living hinge  206 . The flange  204  includes a hook portion  208  having a recess  212  cooperating with a protrusion  214  arranged on an end  216  of the channel  194 . An intermediate wall  210 , or ridge, may be arranged in the channel  194  to form a cavity  200  that is filled with adhesive  202 . The flange  204 , intermediate wall  210 , and protrusion  214  are, for example, santoprene molded onto the frame member  192 . The edge of the fabric  44  is arranged between the flange  204  and protrusion  214 . The flange  204  is forced downward by an upwardly tapering surface  197  of the truck assembly  196 . The hook portion  208  positions the edge of the fabric  44  in the adhesive  202 , and the fabric  44  is additionally retained between the protrusion  214  and recess  212  of the hook portion  208 . Applied heat from the heat source  198  actuates the adhesive  202 .  
         [0054]     As an alternative configuration to the end  216 , edges  218  may be laser welded to one another using a weld bead  222  to form the end  216  shown in  FIG. 15 .  
         [0055]     The example embodiments have been described in an illustrative manner, and it is to be understood that the terminology that has been used is intended to be in the nature of words of description rather than of limitation. Obviously, many modifications and variations of the disclosed examples are possible in light of the above teachings. For that reason, the following claims should be studied to determine their true scope and content.