Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of U.S. application Ser. No. 09/152,029, filed Sep. 11, 1998 and now issued as U.S. Pat. No. 5,992,682, which was a division of U.S. application Ser. No. 08/856,355, filed May 14, 1997 and now issued as U.S. Pat. No. 5,868,276, which applications are hereby incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to a folded sheet material web and assembly, and in particular, to a specific arrangement of a starter sheet material web for a stack of folded webs. The invention also relates to a method and apparatus for folding the starter web. 
     It is well known in the field of facial tissue for an uppermost or starter web of a stack of longitudinally folded webs to be folded back on itself so as to provide a centrally located longitudinally folded edge on a top of the stack as described, for example, in U.S. Pat. No. 3,401,927, issued Sep. 17, 1968 to Frick, and assigned to Kimberly-Clark Corporation, the same assignee of the present application. The folded edge, and overlying folds of the starter web, are provided so as to allow a user to easily grasp and withdraw the uppermost web from the stack, which is typically retained within a carton or similar packaging. It is also well known in the art to provide a next lower web interfolded with the uppermost web so that a portion of the next lower web is withdrawn from the stack as the uppermost web is withdrawn. In this way, the next lower web is exposed to the user for successive removal from the stack. 
     Typically, the overlying folds of the starter web are arranged so that a single uppermost fold extends away from the centrally located longitudinally folded edge and terminates in a free edge proximate the side edge of the stack as shown in Frick U.S. Pat. No. 3,401,927. When arranged in such a configuration, a clip of webs, made from a stack of webs cut to a specified length, experiences what is commonly referred to as a “flying sheets” problem, wherein the top few sheets of the clip fly off the top of the clip as it is transported at high speeds from a saw, where the stack of webs is cut to form the clips, to a cartoner, where the clips are packaged in cartons and the like. Another problem typically encountered with a stack having a web with an uppermost fold terminating in a free edge, whether it be at the side of the stack or at a midpoint, is that the uppermost fold has a tendency to adhere both to a top pull-belt, which is used to urge the stack of webs from a folding board toward the saw, and to hold-down chains, which engage the top of the stack as it passes through the saw. In addition, because the uppermost fold presents two exposed edges, i.e., the centrally located longitudinally folded edge and the outer free edge, the folding process must be closely monitored so as to ensure that the free edge is proximate to the side edge of the stack. If the free edge extends past the side edge, it can be caught on the machinery and the like as the stack is conveyed from the folding board to the saw, and then as the clip is conveyed to the cartoner. Conversely, if the free edge is not aligned with, or falls short of, the side edge, it can present an aesthetically displeasing appearance to the user. 
     To combat the problem of “flying sheets” and adhesion, facial tissue manufacturers commonly are forced to reduce line speeds and/or incorporate additional manufacturing steps, such as spraying liquids on the top sheets, employing weights to hold the top sheets down, applying antistatic products to reduce static, cleaning surfaces to reduce static, and/or controlling the humidity/temperature in the relevant operating areas. Alternatively, additional folds or webs can be introduced in the top sheets, but with the adverse impact of requiring extra sheets to be dispensed on the initial withdrawal by the user. Therefore, the above-mentioned efforts can result in lower productivity, increased manufacturing costs or waste by the user. 
     Another problem encountered with a stack having only a single uppermost web is that the web is susceptible to tearing and the like upon removal by a user. This problem is especially acute when the uppermost web is interfolded with a next lower web, as the next lower web applies forces to the uppermost web as it is being withdrawn. 
     SUMMARY OF THE INVENTION 
     Briefly stated, the invention is directed to a sheet material assembly comprising a stack of longitudinally folded sheet material webs including a first web and second web. The first web includes a first fold, a second fold overlying a portion of the first fold, and a third fold lying between the first and second folds. The second web includes a first fold underlying the first fold of the first web, a second fold overlying the second fold of the first web, and a third fold lying between the first folds and the second folds of the first and second web. 
     In a preferred embodiment, the first and second folds of each of the first and second webs form a first longitudinally folded edge at a side of the stack, and the second and third folds form a second longitudinally folded edge intermediate the sides of the stack, and preferably at an approximate midpoint of the stack. Each of the third folds includes a longitudinal free edge lying between the first and second folds. 
     In one aspect of the invention, the longitudinal free edge of the third fold is proximate to the first longitudinal folded edge such that the first fold underlies substantially the entirety of the second fold. 
     In a preferred embodiment, the second and third folds of the first web are in contact, and the first, second and third folds of the first and second webs are in contact respectively. 
     In another aspect of the invention, a next lower web is interfolded with the first web, or the first and second webs, by providing a fold lying between the first and third folds of the webs. In a similar fashion, a plurality of next lower webs is progressively interfolded with the next lower web and each other. 
     In another aspect of the invention, a folding device is provided for folding a web of sheet material as described above. The folding device has a first, second and third folding edge formed in a first plane and extending from a first junction, with the third folding edge extending between the first and second folding edges. A fourth folding edge also extends from the first junction, but out of the first plane. The folding device also has a fifth and sixth folding edge formed in a second plane and extending from a second junction. The second junction is formed adjacent an end of the first edge opposite the first junction. The second plane is parallel to and positioned above the first plane. The fifth folding edge crosses over the third folding edge in a spaced apart relationship. Finally, the folding device includes a seventh folding edge that extends from the second junction, but out of the second plane. 
     In another aspect of the invention, the first, fourth and seventh folding edges form the edges of a first panel, the second and third folding edges form the edges of a second panel and the fifth and sixth folding edges form the edges of a third panel. In a preferred embodiment, the panels are formed out of a single piece of material, with a fourth panel interconnecting the first and second panels, and a fifth panel interconnecting the first and third panels. 
     In yet another aspect of the invention, a method is provided for forming the sheet material web described above. In particular, the first longitudinal fold is formed by drawing the web over the second, third and fourth folding edges of the folding device. The second longitudinal fold is formed in an overlying relationship with the first fold by drawing the web over the first folding edge of the folding device. Finally, the third longitudinal fold is formed in an overlying relationship with the first fold, and in an underlying relationship with the second fold, by drawing the web over the fifth, sixth and seventh folding edges of the folding device. In a preferred embodiment, a second web is applied to and aligned with the first web prior to the above-described forming process such that the two webs are folded together. 
     The present invention provides significant advantages over other longitudinally folded sheet material webs and assemblies. In particular, by folding the third fold between the first and second folds, the free edge of the third fold is isolated from and not exposed to the air currents and other forces produced by high line speeds. The free edge also is not exposed to the pull-belt that urges the stack of webs toward the saw, or to the hold-down chains engaging the top of the stack. Instead, the uppermost fold, or second fold, has folded edges, with the free edge of the third fold folded under substantially the entirety of the uppermost fold. In this way, the uppermost fold is stabilized, and is therefore less likely to be affected by static, air currents, adhesion and/or other forces tending to strip the top webs from the stack or clip. 
     Moreover, when two sheets are formed together in the preferred embodiment, the uppermost folds are made even more resistant to the “flying sheets” problem and/or adhesion. In contrast, when the free edge is exposed on the uppermost fold, or only turned slightly under the uppermost fold, the uppermost web is less stable. In this way, it can be made more susceptible to the “flying sheets” and adhesion problems, regardless of the number of additional sheet material webs formed with it. Therefore, with the present invention, the speed of the forming process can be substantially increased without encountering “flying sheet” or adhesion problems, and without the need for static reduction, application of weights to the top sheet, humidity control, and/or application of sprays. 
     Moreover, by providing two webs folded together, the sheets are made less susceptible to tearing and the like as the user withdraws the sheets and thereby also withdraws a portion of the next lower web interfolded with the two sheets. 
     In addition, in the present invention, the free edge of the third fold is not exposed at the side of the stack, so that it cannot be snagged on the machinery as the stack of webs travels between the folding board, the saw and the cartoner. In this way, slow-downs and stoppages can be greatly reduced. 
     Similarly, the free edge of the underlying third fold is not visually exposed to the user, so that it does not detract from the aesthetics of the stack. 
     The configuration of the improved folding board facilitates the threading of a new web after stoppages caused by breaks in the web, and the like. In particular, the folding board does not have any guide rods over which an operator must thread the web. The elimination of guide rods also makes the folding board easier to maintain and more reliable. 
     In addition, the configuration of the improved folding board allows the operator to more easily maintain the position of the second longitudinal folded edge at about the midpoint of the stack. In such a position, the web is made more resistant to tearing upon withdrawal by a user. 
     Therefore, the present invention provides a simple but reliable way to make an improved sheet material web and assembly of sheet material webs so as to reduce overall waste while simultaneously increasing output and providing a more robust product for the user. 
     The present invention, together with further objects and advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Many of the features and dimensions portrayed in the drawings, and in particular the presentation of folds, fold lines, folded edges, thicknesses and the like, have been somewhat exaggerated for the sake of illustration and clarity. Moreover, the webs and web folds are shown in the Figures as being spaced apart from each other and from the folding board for the sake of clarity. It should be understood that in actuality, the folds contact each other and the folding board as described below. 
     FIG. 1 is a sectional view of a stack of interfolded webs with a folded uppermost web. 
     FIG. 2 is a sectional view of a stack of interfolded webs with a pair of uppermost webs folded together. 
     FIG. 3 is a top plan view of a folding board. 
     FIG. 4 is a side elevational view of the folding board. 
     FIG. 5 is sectional view of the folding board taken along line  5 — 5  of FIG.  3 . 
     FIG. 6 is a partial enlarged view of the overlying horizontal panels of the folding board shown in FIG.  5 . 
     FIG. 7 is a plan view of the sheet metal blank from which the folding board of FIG. 3 is made. 
     FIG. 8 is a partial enlarged view of the two junctions and fold lines of the blank shown in FIG.  7 . 
     FIG. 9 is a partial enlarged sectional view taken along line  9 — 9  of FIG.  3 . 
     FIG. 10 is a partial enlarged sectional view taken along line  10 — 10  of FIG.  3 . 
     FIG. 11 is a partial enlarged sectional view taken along line  11 — 11  of FIG.  3 . 
     FIG. 12 is a top perspective view of a web applied to the folding board of FIG.  3 . 
     FIG. 13 is a sectional view taken along line  13 — 13  of FIG.  12 . 
     FIG. 14 is a sectional view taken along line  14 — 14  of FIG.  12 . 
     FIG. 15 is a sectional view taken along line  15 — 15  of FIG.  12 . 
     FIG. 16 is a sectional view taken along line  16 — 16  of FIG.  12 . 
     FIG. 17 is a sectional view taken along line  17 — 17  of FIG.  12 . 
     FIG. 18 is a sectional view taken along line  18 — 18  of FIG.  12 . 
     FIG. 19 is a top perspective view of a first and second web applied to the folding board of FIG. 3 with a third web interfolded with the first and second webs. 
     FIG. 20 is a sectional view taken along line  20 — 20  of FIG.  19 . 
     FIG. 21 is a sectional view taken along line  21 — 21  of FIG.  19 . 
     FIG. 22 is a sectional view taken along line  22 — 22  of FIG.  19 . 
     FIG. 23 is a sectional view taken along line  23 — 23  of FIG.  19 . 
     FIG. 24 is a sectional view taken along line  24 — 24  of FIG.  19 . 
     FIG. 25 is a sectional view taken along line  25 — 25  of FIG.  19 . 
     FIG. 26 is a partial perspective view of a clip of sheet material webs deposited in a carton. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings, FIG. 1 shows a sheet material assembly made of a stack  50  of sheet material webs  10 ,  30 ,  40 . Preferably, the sheet material webs are made of facial tissue, and are about 8½ inches wide, although it should be understood by one of skill in the art that other materials of varying widths, such as other papers or foils, can be folded and interfolded as described below. Facial tissue is a particularly fragile type of paper product that typically exhibits greater strength properties in the longitudinal or machine direction, as compared with the lateral or cross direction. 
     It should be understood that the term “web,” as used herein, is meant to include a sheet material made of one or more plies of material so that a multiple-ply sheet material is considered to be a “web” of sheet material, regardless of the number of plies. In addition, the term “longitudinal,” as used herein, is intended to indicate the direction in which the web is folded as it passes over the folding board, and is not intended to be limited to a particular length of the web, whether it is cut, as with a clip, or otherwise. Similarly, the terms “left hand,” “right hand,” “left” and “right” as used herein are intended to indicate the direction relative to the views presented in the Figures, and in particular, from a perspective when viewing the folding board from the front of the board. 
     As shown in FIG. 1, the uppermost web  10  is folded to provide longitudinal web folds  12 ,  14 , and  16 . Web fold  12  is formed from a first half of web  10  and has a longitudinal free edge  18  adjacent to a right-hand side of the stack  50  and a longitudinal folded edge  28  adjacent a left-hand side of the stack  50 . In this way, web fold  12  spans substantially the width of the stack  50 , which is preferably about one half of the width of web  10 . Folded edge  28  is formed by folding web fold  14  over web fold  12 , so that web fold  14  extends from and is bounded by folded edge  28 . 
     In the embodiment shown in FIG. 1, web folds  14  and  16  are formed from the second half of web  10  using a left-hand folding board  70 . It should be understood by one of skill in the art that the web folds can be reversed so that corresponding folds are formed from a opposite half of the web using a right-hand folding board. 
     Web fold  16  is folded under web fold  14  to form an inner longitudinal folded edge  36  lying between and parallel to the side edges of the stack, and preferably at about a midpoint between the side edges. In this way, folded edge  36  defines a longitudinal edge of web folds  14  and  16 . Web fold  16  extends between web folds  14  and  12  toward the left-side of the stack and terminates at a longitudinal free edge  38 , which lies parallel to longitudinal folded edge  28 . Web folds  14  and  16  are in direct contact. Free edge  38  lies inside and adjacent to folded edge  28  and between web fold  14  and web fold  12 . When folded, in this manner, the web  10  assumes a generally flattened e-shaped configuration. Preferably, free edge  38  is proximate folded edge  28  such that web fold  16  underlies substantially the entirety of web fold  14 . In this way, web  10  is made less susceptible to air currents and the like. Moreover, by positioning longitudinal folded edge  36  at an approximate midpoint of the stack, web  10  is made more resistant to tearing upon withdrawal by a user. 
     Web folds  12  and  16  form an opening  160  between them at folded edge  36 . Once the stack is cut into clips of a predetermined length and packaged in a carton or the like, the opening  160  provides a place for the user to insert one or more fingers to grasp the starter web  10  at folded edge  36  and withdraw it from the stack. 
     In a preferred embodiment, shown in FIG. 2, web  20  is folded with web  10 . Web  20  is folded into longitudinal web folds  22 ,  24 , and  26  which lie in direct contact with web folds  12 ,  14 , and  16 , respectively. In particular, web fold  22  underlies and is in direct contact with web fold  12 , web fold  24  overlies and is in direct contact with web fold  14 , and web fold  26  underlies and is direct contact with web fold  16 . Web fold  22  has a longitudinal free edge  42  adjacent the right-hand side of the stack, and a longitudinal folded edge  44  adjacent the left-hand side of the stack. Folded edge  44  of web  20  overlies folded edge  28  of web  10 . Web fold  24  extends between and is bounded by longitudinal folded edge  44  and longitudinal folded edge  46 . Folded edge  46  runs parallel to the side edges of the stack, and preferably at about a midpoint between the side edges. Folded edge  46  of web  20  overlies folded edge  36  of web  10 . Folded edge  46  is formed by folding web fold  26  under web fold  24 . Web fold  26  extends from folded edge  46  into opening  160  between web folds  16  and  12  toward the side of the stack and terminates at a longitudinal free edge  48 , which lies directly underneath and parallel to free edge  38 . Free edge  48  also lies inside and adjacent to the folded edges  44  and  28 . 
     Web folds  26  and  12  form an opening  170  between them at the folded edge  46 . Once the stack is cut into clips of a predetermined length and packaged in a carton  200  as shown in FIG. 26, the opening  170  provides a place for the user to insert one or more fingers to grasp the starter webs  10  and  20  at folded edges  36  and  46  and withdraw them from the stack. In the embodiment shown in FIG. 26, the carton  200  is provided with a longitudinal opening  210  in a top of the carton. The opening  210  is exposed by removing a portion of the carton  200 , typically by tearing the portion along a perforated line. In this way, the longitudinal folded edges  36  and  46 , which are preferably centrally located in the opening  210 , are exposed so that the user may insert one or more fingers through opening  210  into opening  170  and grasp the webs  10  and  20  at folded edges  36  and  46 . 
     By providing two sheet material, webs folded together, the stack is made even less susceptible to the “flying sheets” and adhesion problems in that the air currents and the like are required to strip an additional folded web from the top of the stack. Moreover, by providing two uppermost starter webs  10  and  20  folded together, the assembly is made more robust as the two folded webs are less susceptible to tearing when being grasped and withdrawn by a user from the carton, or like packaging. In this regard, it should be understood additional starter webs can similarly be folded with the first and second webs. 
     As shown in FIGS. 1 and 2, right-hand V-shaped webs  30  and left-hand V-shaped webs  40  are progressively interfolded with webs  10  and  20  and each other. In particular, web  30  includes an upper fold  52  folded over a lower fold  54  to form a longitudinally folded edge  56  at the side of the stack. As shown in FIG. 1, the upper fold of the uppermost web  30  is interfolded between folds  12  and  16  of web  10 . Similarly, in FIGS. 2 and 26, the upper fold  52  is interfolded between web fold  26  of web  20  and web fold  12  of web  10 . Below that, webs  30  and  40  are interfolded using a succession of alternate right-hand and left-hand folding boards as described in U.S. Pat. No. 3,401,927 to Frick, which is hereby incorporated by reference. 
     Alternatively, the lower webs can be formed as upwardly opening C-shaped webs having a base fold, and two wing folds. In such an arrangement, the lower webs are not interfolded, but rather are stacked one upon the other. 
     Folding board  70 , conveniently called a left-hand board as shown in the Figures, is preferably formed from a single piece of sheet metal, or blank  150 , as shown in FIG.  7 . The sheet metal blank is preferably made from #12 Gauge Type 304 Stainless Steel with a #4 finish on both sides. However, it should be understood by one of skill in the art that the folding board can be made out of any rigid material having a suitably smooth surface and edges, such as aluminum or even plastic. The sheet metal blank  150  is bent along bend lines  80 ,  82 ,  83 ,  84  and  86  to form folding board  70 . Alternatively, the folding board can be constructed of several pieces of sheet metal welded together, or mechanically fastened. 
     Folding board  70  includes panels  88 ,  90 ,  92 ,  94  and  96 . Panel  90  may be considered as a base portion, and is typically used in a horizontal position. Panels  90  and  94  are formed by bending the blank  150  along bend line  80  so as to form a folding edge  100  that extends parallel to the path of the webs  10 ,  20  as shown in FIGS. 3,  12  and  19 . Preferably, panels  90  and  94  are bent at about an angle of 123°, 45′ as shown in FIG.  10 . Panel  90  also includes a free folding edge  102  that extends obliquely across the path of the webs  10 ,  20  and intersects folding edge  100  at junction  110 . Panel  90  also includes a sidewardly extending mounting flange  114  having a slotted mounting hole  116  adapted to allow the folding board  70  to be mounted to a support structure, shown in FIG. 4 as a post  180  for the sake of illustration. Preferably, folding edges  100  and  102  of panel  90  form an angle of about 17°, 9′ between them and lie in the same plane. 
     Panel  88  is generally trapezoidal in shape and is formed by bending the blank  150  along bend lines  82  and  84  to form folding edges  104  and  112 , which also define the edges of panels  94  and  96  respectively. Preferably, panels  96  and  88  are bent at about an angle of 106°, 6′ along bend line  84  to form folding edge  112 . Similarly, panels  88  and  94  are bent about the same amount to form folding edge  104 . Panel  88  includes a generally flat portion  120  having a bottom surface  130 , and an upper lip portion  122  that lies generally in a vertical plane. Preferably, flat portion  120  forms an angle of about 60° with the plane defined by panel  90 . The upper lip portion  122  includes two mounting holes  118  adapted to allow the folding board  70  to be mounted to a support structure, shown in FIG. 4 as a post  190  for the sake of illustration. Panel  88  also includes a lower lip portion  126  that extends forwardly from the flat portion  120  and terminates at folding edge  128 . Folding edge  128  extends between junctions  110  and  124  and lies generally in the same plane formed by panel  90  and folding edges  100  and  102 . Junction  110  and  124  are each formed as a rounded notch, preferably having a radius of about 0.09 inches. As shown in FIGS. 7 and 8, junction  124  is slightly offset from, or positioned slightly higher than, junction  110 , so that when the blank is bent along bend lines  80 ,  82 ,  83 ,  84  and  86  as described above, panel  92  is formed parallel to and spaced apart from panel  90  in an overlying fashion. 
     As just described, panel  92  also is typically used in the horizontal position and lies parallel to and above panel  90  as shown in FIGS. 5 and 6. Preferably panel  92  is spaced about 0.06 inches above panel  90 . Panels  92  and  96  are formed by bending the blank along bend line  86  so as to form a folding edge  108  that extends parallel to folding edge  100  and to the path of the web as shown in FIGS. 3,  12  and  19 . Preferably, panels  92  and  96  are bent to form an angle of about 123°, 45′. Panel  92  also includes free folding edge  106 , which extends obliquely across the path of the web and intersects folding edge  108  at junction  124 . Preferably, folding edges  106  and  108  of panel  92  form an angle of about 17°, 9′ between them and lie in the same plane. As shown in FIGS. 4,  5  and  6 , a portion of panel  92  overlies a portion of panel  90 , so that folding edge  106  crosses over folding edge  102  in a spaced apart relationship. 
     Panel  96  extends between panels  88  and  92  and is formed by bending the blank along bend lines  84  and  86  as described above. Panel  94  extends between panels  88  and  90  and is formed by bending the blank along bend lines  80  and  82  as described above. 
     To form the folded web configuration shown in FIG. 1, web  10  is initially provided as a roll of sheet material (not shown). Referring to FIG. 12, the web  10  is pulled from the roll and directed over a guide roll  60  under suitable tension and thereby introduced to the folding board  70  in a generally flat condition as shown in FIGS. 12 and 13. The web  10  is longitudinally directed against the bottom surface of the folding board  70 . Initially, the web  10  is directed against the bottom surface  130  of panel  88  and drawn across folding edges  104  and  112  as shown in FIG.  14 . 
     As the web  10  continues to pass under the board  70 , it is drawn across folding edge  128  to form web fold  14  as shown in FIG.  15 . In particular, as the web  10  is drawn over folding edge  102  and top surface  140 , it is urged inwardly to form longitudinal folded edge  28  at junction  110 , and to begin to form web fold  12 . Similarly, the web  10  is drawn over and urged inwardly by folding edge  106  to form the longitudinal folded edge  36  at junction  120 , which lies parallel to folded edge  28 . The web also begins to form web fold  16  as it is drawn over folding edge  106  and the top surface  142  of panel  92 . The left-hand side of the web also is drawn over folding edge  100  and the bottom surface  132  of panel  90 , while the right-hand side is drawn over folding edge  108  and the bottom surface  134  of panel  92 . 
     As the web  10  is continued to be drawn over folding edge  106 , which extends obliquely inward from junction  124 , the web fold  16  is progressively urged by folding edge  106  beneath web fold  14  as shown in FIG.  16 . Similarly, folding edge  102 , which extends obliquely inward from juncture  110 , progressively urges web fold  12  beneath web fold  14  as the web  10  is drawn over folding edge  102 . Because panel  92  and folding edge  106  are spaced above panel  90  and folding edge  102 , web fold  12  is also progressively urged beneath web fold  16 , so that web fold  16  is formed between web folds  12  and  14 . Eventually, as shown in FIG. 17, web fold  16  is completely formed between web folds  12  and  14  as panel  92  and folding edge  106  end, so that free edge  38  lies between the web folds  12  and  14  inside and adjacent to the folded edge  28 . In this way, the free edge  38  is completely hidden from view and protected between web folds  12  and  14 . As shown in FIG. 17, the web  10  continues to be drawn over folding edge  102  and the bottom surface  132  of panel  90  so as to complete the formation of web fold  12 . As shown in FIG. 18, the completed folded sheet material web is shown as it is drawn over the top surface  140  of panel  90 . 
     As just described, the improved folding board  70 , and method for folding a starter web, eliminates the need for guide rods, and thereby simplifies the folding board and the overall process for making a folded sheet. This, in turn, makes it easier to initially thread the machine and to maintain the device. Moreover, less attention is required to maintain the positioning of the free edge  38 , since it is not visually exposed to the user, and cannot be snagged by the machinery and the like as the web is conveyed from the folding board  70  to the saw, and to the cartoner thereafter. Similarly, the configuration of the folding board  70  makes it easier for the operator to maintain the longitudinal folded edge  36  at about the midpoint of the stack, wherein it is made accessible to the user and wherein web  10  also is made more robust to tearing and the like. 
     In the preferred embodiment, a second roll (not shown) of sheet material web  20  is provided and is applied directly over and aligned with web  10  as the webs pass over guide roll  60  as shown in FIG.  19 . Similarly, it should be understood that additional sheet material webs can be provided and applied to the first and second webs. The webs are formed together as they are drawn across the folding board  70  as described above for the single web  10 , and as shown in FIGS. 19-25. In particular, the webs  10  and  20 , with web  20  overlying web  10 , are longitudinally directed against the bottom surface of the folding board  70 . Initially, the webs  10  and  20  are directed against the bottom surface  130  of panel  88  and drawn across folding edges  104  and  112  as shown in FIG.  21 . 
     As the webs  10  and  20  continue to be drawn beneath the board  70 , they are drawn across folding edge  128  to form web folds  14  and  24  as shown in FIG.  22 . In particular, as the webs  10  and  20  are drawn over folding edge  102 , they are urged inwardly to form longitudinally folded edges  28  and  44  at junction  110 , and to begin to form web folds  12  and  22 . Similarly, the webs  10  and  20  are drawn over and urged inwardly by folding edge  106  to form longitudinally folded edges  36  and  46 , which lie parallel to folded edges  28  and  44 . The webs  10  and  20  also begin to form web folds  16  and  26  as they are drawn over folding edge  106  and the top surface  142  of panel  92 . The left-hand sides of the webs also are drawn over folding edge  100  and the bottom surface  132  of panel  90 , while the right-hand sides are drawn over folding edge  108  and the bottom surface  134  of panel  92 . 
     As the webs  10  and  20  are drawn over folding edge  106 , which extends obliquely inward from junction  124 , the web folds  16  and  26  are progressively urged by folding edge  106  beneath web folds  14  and  24  as shown in FIG.  23 . Similarly, folding edge  102 , which extends obliquely inward from juncture  110 , progressively urges web folds  12  and  22  beneath web folds  14  and  24  as the webs  10  and  20  are drawn over folding edge  102 . Because panel  92  and folding edge  106  are spaced above panel  90  and folding edge  102 , web folds  12  and  22  are also progressively urged beneath web folds  16  and  26 , so that web folds  16  and  26  are folded between web folds  12  and  14 . Eventually, as shown in FIG. 24, the web folds  16  and  26  are completely formed between web folds  12  and  14  as panel  92  ends, so that free edges  38  and  48  lie between the web folds  12  and  14  inside and adjacent to folded edges  28  and  44 . In this way, the free edges  38  and  48  are completely hidden from view and protected between web folds  12 ,  22 ,  14  and  24 . As shown in FIG. 24, the webs  10  and  20  continue to be drawn over folding edge  102  of panel  90  so as to complete the formation of web folds  12  and  22 . As shown in FIG. 25, the completed folded sheet material webs are shown as they are drawn over the top surface  140  of panel  90 . 
     By providing an additional web  20  folded with web  10 , the starter webs are less susceptible to tearing and the like when grasped by a user during the initial withdrawal of the starter webs. In addition, the stack is made more resistant to the “flying sheets” and adhesion problems. 
     An interfolded stack of sheet material webs is produced by interfolding webs  10 ,  20 ,  30  and  40  using a preceding succession of conventional alternate right-hand and left-hand folding boards, as taught, for example, in U.S. Pat. No. 3,401,927 to Frick, referred to above. For example, the uppermost V-shaped web  30  is interfolded with right-hand webs  10  and  20  by passing the upper fold  52  of the web, which is formed by a conventional board immediately preceding folding board  70 , over the top surface of panel  90  as shown in FIGS. 19-25. Similarly, the next lower V-shaped web  40 , formed as a left-hand web, is folded by a conventional folding board immediately preceding the right-hand board so as to interfold webs  30  and  40 . 
     After the stack of webs exits the last folding board  70 , it is carried by belts, including a top pull-belt, to a saw, where the stack is cut laterally across its width to a desired length so as to produce a series of clips. The clips then are carried to a cartoner where they are deposited in a carton, as shown in FIG. 26, or other like packaging. Because the free edges  38  and  48  of web folds  16  and  26  lie inside folded edges  28  and  44  of webs  10  and  20 , and are disposed between web folds  14  and  12 , they are not exposed as the uppermost fold of the stack. Accordingly, the uppermost webs  10  and  20  are less susceptible to being stripped off the top of the clip by air currents, and the like, typically termed the “flying sheets” problem, as the clips are transported from the saw to the cartoner. Instead, the uppermost fold  14  is now bounded by opposite folded edges  28  and  36 . Moreover, free edge  38  and  48  are positioned inside folded edge  28  and  44  and between web folds  12  and  14  so as to not be exposed to machinery and the like. In this way, the free edges  38  and  48  cannot be snagged along the side of the clip and thereby be stripped from the clip, along with any additional interfolded webs. In addition, by folding the free edges  38  and  48  between web folds  12  and  14 , they are not exposed to the top-pull belt urging the stack towards the saw, or to the hold-down chains that direct the stack through the saw. Therefore, the stack is less susceptible to having the uppermost folds or webs adhere to one of the belt or chain and thereby tear, break or otherwise cause a stoppage of the line. By greatly reducing the “flying sheets” and adhesion problems, the speed at which the webs are directed over the folding boards and thereafter introduced to the saws and cartoner can be greatly increased, without the accompanying breaks and waste associated with stacks of sheet material webs interfolded in the conventional manner. 
     As described above, a succession of alternating folding boards can be provided to produce as high a stack of webs as is desired, depending on the number of webs and folding boards. By providing interfolded webs, a portion of the next lower web  30  in a clip is automatically withdrawn by and with the starter web so as to provide a portion of the web  30  for the user to grasp upon the next withdrawal. The opening  170  provided between web folds  26  and  12  at folded edge  46  allows the user to insert one or more fingers to grasp and withdraw the starter webs  10  and  20 . As the user withdraws the next lower web  30  from the clip, it automatically withdraws a portion of the next lower web  40  due to the interfolded nature of the webs  30 ,  40 , and so on. In this way, the successive withdrawal of a web ensures that a portion of the next lower web is also withdrawn. 
     Although the present invention has been described with reference to preferred embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. As such, it is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is the appended claims, including all equivalents thereof, which are intended to define the scope of the invention.

Technology Category: y