Abstract:
A system and method for welding edge seams at the edges of fabric is presented. A method begins by lowering a fabric pre-fold bar onto a piece of fabric. A pre-aligned portion of the fabric is pushed on top of the pre-fold bar so that the pre-fold bar is between the portion of fabric on top of the fabric pre-fold bar and other fabric below the pre-fold bar. The fabric on top of the fabric pre-fold bar is folded edge fabric and fabric not on top of the fabric pre-fold bar is not folded edge fabric. A folded edge is formed between these two sections of fabric. The method pinches some of the fabric at the folded end and then pulls the folded edge fabric off of the fabric pre-fold bar. After that, the method welds at least some of the folded edge fabric to the not folded edge fabric.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority from U.S. Provisional Patent Application Ser. No. 61/722,432, filed Nov. 5, 2012; the disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The current invention relates generally to apparatus, systems and methods for creating seams on plastic fabric. More particularly, the apparatus, systems and methods relate to creating seam edges on plastic fabric using heat. Specifically, the apparatus, systems and methods provide for automatically creating plastic folded seams on the edges of plastic fabric. 
     2. Description of Related Art 
     The creation of seams at the edges of material is well known in the art. In an effort to reinforce fabric around its perimeter, the fabric is typically folded at its edges. The folded fabric is then attached to the underlying fabric to create a perimeter that has twice the fabric thickness as the original sheet of fabric. This provides for a fabric that can be used in awnings and signage that has reinforced edges that can now better withstand weather and wind. Additionally, an elongated pocket can be formed by not completely attaching all of the folded fabric to the underlying sheet of fabric. This allows an elongated structure such as a rod to be slide into the pocket and the rod can be used to hang fabric that is used as signage or to allow the fabric to be mounted to a frame when it is to be used in awning applications. Current methods of manipulating fabric and welding/connecting the folded material to the main sheet of fabric are labor intensive and the fabric is difficult to manipulate. Therefore, a better way of creating a fold at the edges of fabric is desired. 
     SUMMARY 
     The preferred embodiment of the invention is a welding machine that can fold and weld edge seams of fabric. The welding machine includes a lower weld bar secured to a housing, an upper weld bar configured to move up and down and a fabric fold base plate that moves horizontally. The fabric fold base plate includes a fabric position stop and a fabric clamp. The fabric position stop provides a stop to allow an operator to easily align an edge of a piece of fabric with the fabric position stop. After that, the operator can merely press a button and the welding machine folds the edge and welds the edge seam as discussed below without requiring further assistance from the operator. After the fabric edge is placed against the fabric position stop and the button is pressed, the fabric pre-fold bar is lowered onto the fabric. Next, the fabric clamp pushes the edge portion of the fabric on top of the fabric pre-fold bar forming a fabric edge where the edge portion is folded with respect to fabric under the edge portion. The fabric clamp and the fabric base plate then act as pinchers and pinch the fabric edge and pull the fabric off of the fabric pre-fold bar. While continuing to pinch the edge portion, the fabric clamp and the fabric base plate acting as pinchers push the edge portion under the upper weld arm with at least some fabric that is under the edge portion of fabric also positioned above the lower welding bar. Next, the welding machine lowers the upper welding bar onto the edge portion of fabric to weld that fabric to fabric between it and the lower welding arm. 
     Another configuration of the preferred embodiment of the invention is a method of welding a fold at the edge of a piece of fabric. The method begins by lowering a fabric pre-fold bar so that the fabric pre-fold bar is above a piece of fabric. An edge of the fabric would have previously been aligned with a fabric position stop on a welding machine. A portion of the fabric is then pushed so that a portion of fabric is on top of the pre-fold bar so that the pre-fold bar is between the portion of fabric on top of the fabric pre-fold bar and other fabric below the pre-fold bar. The fabric on top of the fabric pre-fold bar is folded edge fabric and fabric not on top of the fabric pre-fold bar is not folded edge fabric. A folded end is formed where the folded edge fabric and not folded edge are folded. Next, some of the fabric at the folded end is pinched and pulled off of the fabric pre-fold bar. At least some of the folded edge fabric is then welded to the not folded edge fabric. For example, all of the folded edge fabric can be welded to the not folded edge fabric to create a continuous solid weld or only part of the folded edge fabric (a part beginning at the edge of the fabric) can be welded to create a pocket or un-welded area between the weld and the folded end. 
     In one configuration of the preferred embodiment, a button can be pushed and then the lowering the fabric pre-fold bar, the pushing a portion of the fabric, the pinching some of the fabric at the folded end, the pulling the folded edge fabric off of the fabric pre-fold bar and the welding are all preformed automatically after the button is pushed. 
     Another configuration of the preferred embodiment is a welding machine that folds and welds edge seams of a fabric. The welding machine includes a weld bar, a fabric pre-fold bar that moves up and down and a fabric fold base plate. The fabric clamp pushes a portion of the fabric on top of the fabric pre-fold bar. The fabric that is on top of the fabric pre-fold bar is folded edge fabric and fabric that is under the fabric pre-fold bar is not folded edge fabric. A folded end is formed where the folded edge fabric and the not folded edge are folded. The fabric clamp and the fabric base plate then pinch the folded end and pulls the folded edge fabric off of the fabric pre-fold bar and then pushes the folded end adjacent the weld bar. The weld bar welds together at least some of the folded edge fabric and the not folded edge fabric. 
    
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
       One or more preferred embodiments that illustrate the best mode(s) are set forth in the drawings and in the following description. The appended claims particularly and distinctly point out and set forth the invention. 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate various example methods, and other example embodiments of various aspects of the invention. It will be appreciated that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. One of ordinary skill in the art will appreciate that in some examples one element may be designed as multiple elements or that multiple elements may be designed as one element. In some examples, an element shown as an internal component of another element may be implemented as an external component and vice versa. Furthermore, elements may not be drawn to scale. 
         FIG. 1  illustrates a perspective view of a preferred embodiment of an edge seam welding machine. 
         FIG. 2  illustrates a front view of the preferred embodiment of the edge seam welding machine. 
         FIG. 3  illustrates a side view of the preferred embodiment of the edge seam welding machine. 
         FIG. 4  illustrates a cross-sectional side view of the preferred embodiment of the edge seam welding machine. 
         FIG. 5A  illustrates a cross-sectional side view of the preferred embodiment of the edge seam welding machine as fabric is being aligned with a front edge of a fabric position stop. 
         FIG. 5B  illustrates a cross-sectional side view of the preferred embodiment of the edge seam welding machine as a fabric pre-fold bar is lowered onto the fabric. 
         FIG. 5C  illustrates a cross-sectional side view of the preferred embodiment of the edge seam welding machine as a fabric clamp pushes fabric over the pre-fold bar. 
         FIG. 5D  illustrates a cross-sectional side view of the preferred embodiment of the edge seam welding machine as the fabric clamp begins to clamp the fabric. 
         FIG. 5E  illustrates a cross-sectional side view of the preferred embodiment of the edge seam welding machine as the fabric clamp pulls the fabric off the pre-fold bar. 
         FIG. 5F  illustrates a cross-sectional side view of the preferred embodiment of the edge seam welding machine as the fabric clamp pushes the folded fabric onto a lower welding bar. 
         FIG. 5G  illustrates a cross-sectional side view of the preferred embodiment of the edge seam welding machine as an operator removes the welded fabric from the welding machine. 
         FIG. 6A  illustrates the position of fabric relative to the upper and lower welding bars when the welding machine is used to create a weld with a small pocket. 
         FIG. 6B  illustrates the position of fabric relative to the upper and lower welding bars when the welding machine is used to create a weld with essentially no pocket. 
         FIG. 6C  illustrates the position of fabric relative to the upper and lower welding bars when the welding machine is used to create a weld with a large pocket. 
     
    
    
     Similar numbers refer to similar parts throughout the drawings. 
     DETAILED DESCRIPTION 
       FIGS. 1-4  illustrate the preferred embodiment of a welding machine  1  used to create folds at the edge of a sheet of fabric. The welding machine  1  has a housing  2  that includes a housing left support end  3 , a housing right support end  5 , an upper housing  7  and a central work area housing  9 . Wheels  11  can be attached to a lower end  13  of the housing left support end  3  and a lower end  15  of the housing right support end  5  to allow the welding machine  1  to be easily moved from one location to another. Alternatively, pedestals or other supporting devices can be located under the lower end  13  of the housing left support end  3  and the lower end  15  of the housing right support end  5 . 
     The housing left support end  3  includes a left housing base portion  17  and a left housing arm  19  and the housing right support end  5  includes a right housing base portion  21  and a right housing arm  23 . The housing left support end  3  and the housing right support end  5  are essentially mirror images of each other so only the housing right support end  5  ( FIG. 3 ) is described here but its description generally applies to the housing left support end  3 . The right housing arm  23  is formed out of three generally trapezoidal shaped sections  25 A-C arranged in series. The right housing base portion  21  has a front portion  27  that is formed with a generally L-shaped arm  29 . The L-shaped arm  29  creates a portion of a trapezoidal shaped cutout that together with the central work area housing  9  forms an elongated channel  31  that extends downward from upper surfaces  33 ,  35  and spans the elongated length of the central work area housing  9 . The channel  31  provides an area into which fabric may easily be manipulated/stored during the process of creating an edge weld as discussed below. 
     A cross-section of the upper housing beam  7  is generally square/rhombus in shape ( FIG. 4 ). The upper housing beam  7  is attached at both ends to upper ends  37  of the left housing arm  19  and the right housing arm  23 . The central work area housing  9  includes a front upper surface  33  and a back upper surface  35  that is elongated with both their ends spanning from the left housing base portion  17  to the right housing base portion  21 . In general, the housing  2  and its components are given structure and shape by connecting elongated hollow square beams, hollow rectangle beams, angled bars and other rigid structures together as shown in  FIG. 4  to form a frame of the welding machine  1 . Sheet metal is used to cover the frame to make it functional, safe, attractive and easy to clean. Of course, other materials can be used to form the frame and other materials can be used to cover the frame. 
     Beams  39  and walls of the upper housing beam  7  form an elongated interior  41  best seen in  FIG. 4 . A first row of air cylinders  43  are mounted in the interior  41  of the upper housing beam  7  that are connected to an elongated upper welding bar  45  with pistons  46 . A second row of air cylinders  47  are mounted in the interior  41  of the upper housing beam  7  that are connected with pistons  48  to an elongated fabric pre-fold bar  49 . The first row of air cylinders  43  and the second row of air cylinders  47  are pneumatically controlled to raise and lower the upper welding bar  45  and the fabric pre-fold bar  49 , respectively, in the direction of arrows A and B ( FIG. 4 ) independently of each other. The upper welding bar  45  and the fabric pre-fold bar  49  can be retracted into an at least partially transparent cover  51  extending downward from the upper housing beam  7 . 
     A lower welding bar  53  is rigidly mounted adjacent the upper surface  35  of the central work area housing  9  directly under the upper welding bar  45  ( FIG. 4 ). The central work area housing  9  further includes a fabric fold base plate  55  that provides a mount for a fabric clamp  57  and a fabric position stop  59 . The fabric fold base plate  55 , the fabric clamp  57  and the fabric position stop  59  form what will be referred to as a fabric positioning assembly  70 . The fabric clamp  57  can be pivotally connected to the fabric fold base plate  55  with a hinge device  61  or another connection that allows it to pivot. Motors, gears, pneumatic actuators and the like can control the fabric fold base plate  55  to move it back and forth in the directions of arrow C ( FIG. 4 ) and cause the fabric clamp  57  to open and close with respect to a front end  63  ( FIG. 5A ) of the fabric fold base plate  55 . For example, pneumatic cylinder  110  can control lever  111  to cause the fabric positioning assembly  70  to move in the directions of arrow D and pneumatic cylinder  114  can through lever  115  cause the fabric clamp to open and close. A controller logic  65  ( FIG. 1 ) in the housing  2  can control the motors, gears, pneumatic actuators and the like to control the movements of the fabric clamp  57  and the fabric fold base plate  55 . The position of the fabric position stop  59  can also be moved with respect to arrow D and moved into a desired position on the fabric fold base plate  55 . A front end  67  of the fabric clamp  57  and the front end  63  of fabric fold base plate  55  can be tapered so that they form a pointed edge. 
     “Logic”, as used herein, includes but is not limited to hardware, firmware, software and/or combinations of each to perform a function(s) or an action(s), and/or to cause a function or action from another logic, method, and/or system. For example, based on a desired application or needs, logic may include a software controlled microprocessor, discrete logic like an application specific integrated circuit (ASIC), a programmed logic device, a memory device containing instructions, or the like. Logic may include one or more gates, combinations of gates, or other circuit components. Logic may also be fully embodied as software. Where multiple logics are described, it may be possible to incorporate the multiple logical logics into one physical logic. Similarly, where a single logical logic is described, it may be possible to distribute that single logic between multiple physical logics. 
     Having described the structure of the welding machine  1  and its key components, its operation and use will now be described. In general, the improved welding machine  1  provides for a much more automated way of creating folded edge seams and pockets than prior art machines. As mentioned above, the thickness of the edge seam (and its pocket if one is desired) is controlled by adjusting the position of the fabric position stop  59  with respect to the fabric fold base plate  55 . For example a wing nut of a bolt passing through the fabric position stop  59  and the fabric fold base plate  55  can be loosened. Next, the fabric position stop  59  is slid as indicated by arrows D in  FIG. 4  to a desired position with respect to the fabric fold base plate  55  so that a desired edge seam thickness is created. For example, in the preferred embodiment the upper welding bar  45  and the lower welding bar  53  have a 25 mm thickness to allow up a 25 mm edge seam to be created and the fabric position stop  59  can be positioned far enough to the left to create a 25 mm weld with a 2.5 inch pocket.  FIG. 6A  illustrates the positioning of a piece of fabric  80  with respect to the upper welding bar  45  and the lower welding bar  53  after the fabric position assembly  70  has manipulated them (as discussed below) in preparation for a 25 mm weld with about a 25 mm pocket.  FIG. 6B  illustrates the positioning of a piece of fabric  80  with respect to the upper welding bar  45  and the lower welding bar  53  after the fabric position assembly  70  has manipulated them (as discussed below) in preparation for about a 25 mm weld without any pocket.  FIG. 6C  illustrates the positioning of a piece of fabric  80  with respect to the upper welding bar  45  and the lower welding bar  53  after the fabric position assembly  70  has manipulated them (as discussed below) in preparation for a 25 mm weld with a large 2.5 inch pocket  81  that is not welded. 
     After the fabric position stop  59  is adjusted with respect to the fabric fold base plate  55  for a desired edge seam thickness, the process of creating an edge seam begins with the upper welding bar  45  and the fabric pre-fold bar  49  in raised positions (see  FIG. 5A ), preferably four inches or more above the lower welding bar  53  and the upper surface  35  of the central work area housing  9 . This allows an operator to slide a piece of fabric  80  in the direction of arrow E along the upper surface  35  of the central work area housing  9  over the lower welding bar  53  so that a perimeter edge  82  of the fabric  80  is pushed up to and is adjacent a front edge  84  of the fabric position stop  59 . In the preferred embodiment, upon placing the fabric  80  in this position the operator of the welding machine  1  merely presses a button to begin a series of actions by the welding machine  1  and its fabric positioning assembly  70 . 
     First, as shown in  FIG. 5B  the fabric pre-fold bar  49  is lowered in the direction of arrow F by its air-cylinders  47 . Next, pneumatic cylinder  114  moves its piston in the direction of arrow G ( FIG. 5C ) to cause the fabric clamp  57  to open a bit in the direction of arrow H. Next, the fabric position assembly  70  is moved to the left in the direction of arrow I so that the portion of fabric resting on top of the fabric clamp  57  is pushed in the direction of arrow J over top of the fabric pre-fold bar  49 . Next, the fabric positioning assembly  70  is moved to the left as shown in  FIG. 5C  so that the front end  67  of the fabric clamp  57  is above a right side portion  74  of the fabric pre-fold bar  49  and the front end  63  of the fabric fold base plate  55  is under right side portion  74  of the fabric pre-fold bar  49 . Next, as shown in  FIG. 5D  the pneumatic cylinder  114  causes through lever  115  the fabric clamp  57  to lower in the direction of arrow L so that a folded end  150  of the fabric  80  is pinched between the fabric clamp  57  and the fabric fold base plate  55 . Note that the fabric on top of the fabric pre-fold bar is folded edge fabric  151  and fabric not on top of the fabric pre-fold bar is not folded edge fabric  152 . After that, the fabric positioning assembly  70  is moved to the right in the direction of arrow M ( FIG. 5E ) and the fabric pre-fold bar  49  is moved upward in the direction of arrow N. Finally, as shown in  FIG. 5F , the fabric positioning assembly  70  is move in the direction of arrow O to the left to position the folded portion of the fabric  80  between the two welding bars  45 ,  53  and then the upper welding bar  45  is lowered in the direction of arrow P so that the folded portion of the fabric is pressed together and held for a long enough time so that the a weld  155  is formed between the two fold pieces of fabric. 
     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. Therefore, the invention is not limited to the specific details, the representative embodiments, and illustrative examples shown and described. Thus, this application is intended to embrace alterations, modifications, and variations that fall within the scope of the appended claims. 
     Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described. References to “the preferred embodiment”, “an embodiment”, “one example”, “an example”, and so on, indicate that the embodiment(s) or example(s) so described may include a particular feature, structure, characteristic, property, element, or limitation, but that not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element or limitation. Furthermore, repeated use of the phrase “in the preferred embodiment” does not necessarily refer to the same embodiment, though it may.