Patent Publication Number: US-8535483-B2

Title: Apparatus for uniquely perforating a web material

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to apparatuses for perforating a web. More particularly the present invention relates to apparatuses of this type having significantly improved reliability, lower manufacturing costs, greater flexibility, and higher perforation quality. 
     BACKGROUND OF THE INVENTION 
     For many years, it has been well known to perforate products manufactured from webs such as paper towels, bath tissue and the like to thereby facilitate the removal of sheets from a roll by tearing. There have been proposed a variety of types of mechanical apparatus and numerous different methods for forming the perforations for these products. Typically, a moving blade has been utilized to perforate a web as it passes between the moving blade and a stationary anvil where the moving blade extends perpendicular to the direction of travel of the web. 
     While this conventional operation has been widely adopted, there are a number of well known drawbacks in terms of the overall reliability, manufacturing costs, flexibility, and perforation quality. Among the drawbacks is the fact that the interaction of the moving blade and the stationary anvil is known to impose a speed limitation since vibrations produced at high speeds adversely affect the overall quality of the perforations formed in a web. Further, the vibrations caused by the interaction of the moving blade and stationary anvil may result in costly web breaks or equipment malfunctions requiring a shutdown of the manufacturing operation. 
     For instance, it is known that the teeth on the moving blade become dull or broken after a period of use. This not only will result in an inferior and unacceptable level of perforation quality, but it will also require a temporary shutdown of the manufacturing operation to replace the moving blade and to discard inferior product produced immediately prior to shutdown. As will be appreciated, this results in unacceptable waste and significantly increased manufacturing costs. 
     In addition, another drawback to conventional equipment has been the inability to quickly change from one perforation pattern format (or sheet length) to another without significant down time for the changeover. It has typically been the case that this type of changeover requires the manufacturing operation to be shut down for at least several hours. While the changeover is occurring, there is obviously no product being produced and personnel must be actively engaged in implementing the changeover, all of which leads to significantly increased manufacturing costs. 
     In another respect, there has been a continuing need for greater flexibility in order to produce products having enhanced consumer desirability. For instance, it would be desirable to be able to produce both linear and nonlinear perforations as well as perforations extending in both the cross and machine directions. While various approaches have been suggested, none have offered the requisite level of perforation quality that would result in a fully acceptable product. 
     Additionally, it would be desirable to have perforations that are sufficiently strong to withstand winding of a web but also sufficiently weaken the web at least at the edges to facilitate the separation of one sheet from the next. Further, it would be desirable to have a wound or rolled perforated web product which is manufactured in such a manner that is possible for a line of perforations to complement, register with, or match an embossed or printed pattern on the web. 
     While various efforts have been made in the past which were directed to overcoming one or more of the foregoing problems and/or to providing one or more of the foregoing features, there remains a need for perforating apparatuses and methods and perforated web products having improved reliability, lower manufacturing costs, greater flexibility, and higher perforation quality. 
     SUMMARY OF THE INVENTION 
     While it is known to manufacture perforated web products such as paper towels, bath tissue and the like to facilitate the removal of sheets from a roll by tearing, it has remained to provide perforating apparatuses and methods and perforated web products which overcome the noted problems and provide the noted features. Embodiments of the present disclosure provide perforating apparatuses having improved features that result in multiple advantages including enhanced reliability, lower manufacturing costs, greater flexibility, and higher perforation quality. Such apparatuses not only overcome the noted problems with currently utilized conventional manufacturing operations, but they also make it possible to design and produce perforated products such as paper towels, bath tissue, and the like having enhanced practical and aesthetic desirability for the consumer. 
     In certain embodiments, the apparatus utilizes a rotatable male roll and a rotatable female roll wherein a pocket in the female roll is located to receive perforating elements on the male roll during rotation. Further, the apparatus causes rotation to be imparted to the male and female rolls while the web is transported between them to cause the pocket to receive the perforating elements to form a selected perforation pattern. In these embodiments, the apparatus causes the male roll to be positioned in relation to the female roll such that web engaging edges defined by the perforating elements on the male roll are closely spaced from a web supporting edge defined by the pocket in the female roll. Specifically, the web engaging edges on the male roll are closely spaced from the web supporting edge of the female roll by a distance permitting the web engaging edges to overstrain the web without contacting the web supporting edge when the perforating elements are received in the pocket. 
     A female embossing pattern may be provided on an outer surface of the female roll and a male embossing pattern may be provided for engagement with the female embossing pattern to form a selected embossing pattern on the web. The web engaging edges and the web supporting edge may then be located in relation to the respective male and female embossing patterns so the selected perforation pattern is formed by overstraining the web to complement, register with, or match the selected embossing pattern. Additionally, the apparatus and method may utilize a pair of male rolls and a female roll having a pair of pockets so each of the pockets in the female roll is adapted to receive the perforating elements on a different one of the male rolls when it is placed in an operative position. 
     Specifically, the male rolls are each adapted to be moved from an inoperative position to an operative position relative to the female roll. The perforating elements on each of the male rolls are suitably located at a different circumferential position to be received within a different one of the pockets in the female roll. In this manner, it is possible to move a selected one of the male rolls to an operative position to produce one of two different perforation pattern formats. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exemplary apparatus for perforating a web utilizing a rotatable male roll having perforating elements defining web engaging edges and a rotatable female roll having a pocket for receiving the perforating elements and defining a web supporting edge; 
         FIG. 2  is a side elevational view showing the exemplary apparatus for perforating a web of  FIG. 1  perforating element overstraining a web; 
         FIG. 3  is a detailed view of the region labeled  3  of  FIG. 1 ; 
         FIG. 4  is a detailed view of the region labeled  4  of  FIG. 1 ; 
         FIG. 5  is an alternative perspective view of an exemplary apparatus for perforating a web including a female emboss pattern on the female roll, a male emboss pattern on the male roll, nonlinear perforating elements on the male roll and a nonlinear pocket in the female roll to receive the nonlinear perforating elements; 
         FIG. 6  is a schematic view illustrating one manner of adjusting the apparatus of  FIG. 1  to vary the perforations; 
         FIG. 7  is an alternative schematic view illustrating separate male rolls for perforating and embossing; 
         FIG. 8  is a schematic view illustrating two male rolls for perforating a web to form different sheet lengths; 
         FIG. 9  is a plan view of a web product having an embossed or printed pattern formed thereon and also having a selected perforation design formed utilizing the apparatus of  FIG. 1 ; 
         FIG. 9A  is a plan view of a web product having a selected perforation design extending in the cross direction as well as in the machine direction utilizing the apparatus of  FIG. 1 ; and 
         FIG. 10  is a perspective view of an alternative apparatus for perforating a web utilizing a rotatable ring roll and a rotatable pattern roll and having perforating elements and pockets located to form nonlinear perforations in both the cross direction and the machine direction. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As used herein, the term “machine direction” (MD) means the direction of travel of a web through any processing equipment. The term “cross direction” (CD) is orthogonal and coplanar thereto. The term “Z-direction” is orthogonal to both the machine and cross directions. 
     The various embodiments of the present disclosure described in detail below provide several non-limiting examples of perforating apparatuses, methods, and several distinct perforated web products having improved features which result in enhanced reliability, lower manufacturing costs, greater flexibility, and higher perforation quality. With regard to these non-limiting examples, the described apparatuses and methods make it possible to effectively and efficiently design and produce a variety of different perforated web products having enhanced practical and aesthetic desirability. 
     Referring to  FIG. 1 , an exemplary apparatus  200  for perforating a web includes a rotatable male roll  202  and a rotatable female roll  204 . The male roll  202  includes perforating elements  206  that define web engaging edges  206   a . The web engaging edge  206   a  of each of the perforating elements  206  is spaced outwardly from an outer surface  208  of the male roll  202  for overstraining a web  210  (see also  FIGS. 2 and 4 ). The female roll  204  is provided with at least one pocket  212  that defines a web supporting edge  214 . The pocket  212  defines the web supporting edge  214  and extends inwardly to define a recess in an outer surface  216  of the female roll  204  to receive the perforating elements  206  and web  210  therein.  FIGS. 1-4  detail how the pocket  212  in the female roll  204  receives the perforating elements  206  and web  210 . 
     In particular,  FIGS. 1 and 2  illustrate that the perforating so that the pocket  212  in the female roll  204  receives the perforating elements  206  on the male roll  202  during rotation of the male roll  202  and the female roll  204 . More specifically, the male roll  202  is positioned relative to the female roll  204  so the web engaging edges  206   a  are closely spaced from the web supporting edge  214  by a distance selected to permit the web engaging edges  206   a  to overstrain the web  210  without making contact with the web supporting edge  214 . In other words, when the perforating elements  206  on the male roll  202  are received in the pocket  212  in the female roll  204  as illustrated in  FIG. 2 , the web engaging edges  206   a  defined by the perforating elements  206  will be closely spaced from, but not make contact with, the web supporting edge  214 . 
     As shown in  FIG. 2 , the web  210  is transported along a path between the male roll  202  and the female roll  204  by a device which may comprise a conventional web re-winder as is well known in the art. In addition, rotation is imparted to the male roll  202  and the female roll  204  by a conventional motor and gear arrangement as is also well known in the art. In this manner, the perforating elements  206  are arranged for pushing the web  210  into the pocket  212  to force the web  210  against the web supporting edge  214  during rotation of the male and female rolls. 
     As will be appreciated, the web engaging edge  206   a  defined by each of the perforating elements  206  on the male roll  202  overstrains the web  210  at a single location in cooperation with the web supporting edge  214 .  FIG. 2  illustrates that the male roll  202  is positioned in relation to the female roll  204  to provide a selected degree of overstraining by selecting a predetermined distance for the web engaging edge  206   a  to extend into the pocket  212  and selecting the distance the web engaging edge  206   a  is spaced from the web supporting edge  214 . By selecting these two distances, it is possible to control the degree of web engagement which in turn controls the degree of web overstraining and therefore the size and characteristics of the perforations. 
     Since the degree to which the web  210  is overstrained can be controlled, the weakening of a selected area can be accomplished without the web engaging edge  206   a  ever contacting the web supporting edge  214  or the bottom of the pocket  212  by disrupting the fiber structure of the web  210  by a desired amount up to and including a condition wherein the web  210  has been sheared. 
     As used throughout the specification and claims, the word “overstrain” and any variants thereof means either 1) to disrupt the fiber structure of a web to weaken it by compressing or moving the fibers apart, or 2) to deflect or displace a web in the “Z” direction, i.e., perpendicular to the plane or surface of a web, or 3) to deflect or displace a web sufficiently to provide a visually perceptible perforation, or 4) to extend completely through a web, facilitating tearing by a consumer at defined locations, e.g., along rolls of paper towels, bath tissue, and the like. 
     As used throughout the specification and claims, the phrase “degree of overstraining” and any variants thereof means either 1) the extent to which the fibers in a web are compressed or moved apart, or 2) the extent to which the web is deflected or displaced in the “Z” direction, i.e., the direction perpendicular to the plane or surface of a web, or 3) the size of openings which are formed in a web, which determines the strength or weakness of the web after a selected perforation design has been formed in the web. 
     Additionally, and as used throughout the specification and claims, the phrase “degree of weakening” and any variants thereof, means the extent to which the strength of the web material between successive sheets has been weakened as a result of penetration of the web by perforating elements which can be controlled by selecting the size and/or the shape of each of the perforating elements  206 . Specifically, the size of each of the perforating elements  206  including all of its dimensions including but not limited to its depth or length and/or its perimeter dimension and/or its breadth as well as its shape (e.g.,  FIGS. 2 and 4  provide one example of the wide variety of shapes that can be utilized to form perforations in a web) may be individually selected to provide the perforating elements with the same or different depths or lengths and/or perimeter dimensions and/or breadths and/or shapes or footprints of engagement with the web to thereby control the degree of weakening of the web (e.g., in the cross and/or machine directions). Furthermore, the depths to which the perforating elements  206  extend can be controlled not only by varying the lengths of some or all of the perforating elements  206  but also by controlling the distance between the respective axes of the rotatable male roll and the rotatable female roll to thereby control the extent to which the perforating elements  206  extend into the pocket formed in the female roll. 
     By employing one or more of these techniques, each line of perforation can be provided with a differential perforation strength. For instance, the perforations in the cross direction of the web  210  can be formed to be weaker at or near the edges of the web  210  than the perforations in the middle of the web  210  to facilitate starting a tear of one sheet from the next adjacent sheet on the web  210 . In this manner, the perforations in the middle of the web  122  can be stronger so the web  210  can withstand material handling forces during manufacturing. 
     Referring to the relationship between the perforating elements  206  and the pocket  212  in  FIG. 2 , the pocket  212  forms a recess in the outer surface  216  of the female roll  204  and is larger, i.e., deeper and wider, than the perforating elements  206  extending outwardly from the outer surface  208  of the male roll  202 . This relationship of sizes between the perforating elements  206  and the pocket  212  serves to permit the perforating elements  206  to be received within the pocket  212  without actually making contact with any of the surfaces defining the pocket  212  as both the male roll  202  and the female roll  204  rotate about their respective axes. As shown in  FIGS. 1 and 2 , the perforating elements  206  extend outwardly from the outer surface  208  of the male roll  202  and the pocket  212  extends inwardly of the outer surface  216  of the female roll  204  in generally radial directions relative to the male roll  202  and the female roll  204  respectively. 
     While there are multiple sets of the perforating elements  206  and pockets  212  provided on the male roll  202  and in the female roll  204 , respectively, in the non-limiting example of  FIG. 1 , it will be appreciated that only a single set is required. Typically, although not required, when multiple sets of the perforating elements  206  and pockets  212  are used, they will be equally circumferentially spaced about the outer surface  208  of the male roll  202  and the outer surface  216  of the female roll  204 , respectively. In this connection, there will be a separate pocket  212  to receive each one of the multiple sets of perforating elements  206  during rotation of the male roll  202  and the female roll  204  for forming repeating lines of perforation in the web  210 . 
     As shown in  FIG. 1 , the perforating elements  206  in a non-limiting example may be disposed from one end  218  to the other end  220  of the male roll  202 . The perforating elements  206  also may be disposed in a linear fashion as shown, in a nonlinear fashion as illustrated in  FIG. 5 , or in any arrangement having both machine and cross directions. In either case, the perforating elements  206  are positioned to be in selected cooperative alignment with an appropriately sized and correspondingly shaped pocket  212 . 
     In other words, the perforating elements  206  are positioned relative to the pocket(s)  212  generally in the manner shown in  FIGS. 1 and 5 . However, in a broader sense, the perforating elements  206  may be located in a collectively linear fashion as shown in  FIG. 1 , or in a collectively nonlinear (arcuate) fashion as generally shown in  FIG. 5 , or in any other desired combination or manner. The only limitation is that each of the perforating elements  206  must be positioned to be received within a corresponding pocket  212 . 
     Thus, simply by selecting the desired location for each of the perforating elements  206 , it is possible to produce a perforation pattern which may be linear or may be any nonlinear pattern wherein  FIG. 5  is but a single example. The actual location of each of the perforating elements  206  shown in  FIGS. 1 and 5  are merely non-limiting examples. As long as one or more pockets  212  may be formed in the female roll  204  to receive every one of the individual perforating elements  206  on the male roll  202 , it is possible to produce virtually any desired perforation pattern. 
     Referring to  FIG. 5 , the female roll  204  may have a selected female embossing pattern  222  in the outer surface  216 . There may also be provided a corresponding male embossing pattern  224  for engagement with the female embossing pattern  222 . A selected embossing pattern may thereby be formed on the web  210  by engaging the male and female embossing patterns. 
     In the non-limiting example of  FIG. 5 , the male embossing pattern  224  is provided on the outer surface  208  of the male roll  202 . However, as shown in  FIG. 7 , the male embossing pattern may be formed on a rotatable male embossing roll  226 . In this manner, both the male perforating roll  202  and the male embossing roll  226  are operatively associated with the female roll  204 . 
     As shown in  FIG. 7 , the positions of the male perforating roll  202  and the male embossing roll  226  in relation to the female roll  204  are independently adjustable to controllably adjust the perforating and embossing functions as indicated by the arrowed lines  227   a  and  227   b.    
     In either case, the pockets  212  in the female roll  204  are located relative to the female embossing pattern  222  so the selected perforation pattern produced by the web engaging edges  206   a  of the perforating elements  206  complements, registers with, or matches the selected embossing pattern produced by the male and female embossing patterns  222  and  224 . 
     As shown in  FIG. 5 , the male embossing pattern  224  may be formed on the outer surface  208  of the male roll  202  in spaced relation to the perforating elements  206  and positioned such that the female embossing pattern  222  in the outer surface  216  of the female roll  204  will engage the male embossing pattern  224  on the male roll  204  during rotation of the male and female rolls. 
     Alternatively, the male embossing pattern such as  224  may be formed on the outer surface  228  of the rotatable male embossing roll  226  and positioned so the female embossing pattern  222  in the outer surface  216  of the female roll  204  will engage the male embossing pattern  224  on the male embossing roll  226  during rotation of the female roll  204  and the male embossing roll  226  ( FIG. 7 ). 
     As shown in  FIG. 5 , the shape of the selected embossing pattern formed by the female and male embossing patterns  222  and  224 , and the selected perforation pattern formed by the shape of the set(s) of perforating elements  206  and the pocket(s)  212  may both be nonlinear and have complementary, registering or matching curvatures or shapes in a non-limiting embodiment. 
     Referring once again to  FIG. 1 , the perforating elements  206  on the male roll  202  are disposed generally parallel to an axis of rotation  230  for the male roll  202 , and the pocket  212  in the female roll  204  is disposed generally parallel to an axis of rotation  232  for the female roll  204 . Further, in this non-limiting embodiment, it will be seen that at least two sets of the perforating elements  206  on the male roll  202  and at least two pockets  212  in the female roll  204  are spaced circumferentially about the outer surfaces  208  and  216  of the male and female rolls, respectively. 
     Referring to  FIG. 6 , the degree to which the perforating elements  206  extend into the pocket  212  to be a predetermined depth may be controlled by adjusting the position of the male roll  202  relative to the female roll  204  as represented by the arrow  234 . Alternatively, the predetermined depth may be controlled by adjusting the position of the female roll  204  relative to or further away from the male roll  202 . Yet still, the degree to which the perforating elements  206  extend into the pocket  212  to be a predetermined depth may be controlled by adjusting the positions of the male roll  202  and the female roll  204  relative to each other. 
     In addition to adjusting the position of the male roll  202  relative to the female roll  204  to control the degree of web engagement by controlling the extent or predetermined depth to which the perforating elements  206  are received within the pocket  212 , the perforating elements  206  may be suitably sized and/or shaped to provide differing degrees of web overstraining when the perforating elements  206  of the male roll  202  are received in the pocket  212  of female roll  204 . As another way of controlling the degree of web overstraining, the distance by which the web engaging edges  206   a  defined by the perforating elements  206  are closely spaced from the web supporting edge  214  defined by the pocket  212  may be selected and varied as still another way to control the degree or size of the perforations or weaknesses formed in the web  210 . 
     Referring to  FIG. 8 , another non-limiting embodiment is illustrated in which the apparatus  200  includes a pair of rotatable male rolls  202   a  and  202   b  together with a central rotatable female roll  204 . In this connection, each of the male rolls  202   a  and  202   b  will be understood to have perforating elements  206  defining web engaging edges  206   a  spaced outwardly of an outer surface  208  of the type generally illustrated in  FIG. 1 . With regard to the female roll  204 , it will have a pair of pockets  212  each defining a web supporting edge  214  where the pockets  212  extend inwardly of an outer surface  216  generally as illustrated in  FIG. 1 . 
     With this arrangement, the perforating elements  206  on the male rolls  202   a  and  202   b  and the pockets  212  in the female roll  204  are located so each of the pockets  212  in the female roll  204  will receive the perforating elements  206  on a different one of the male rolls  202   a  and  202   b  during rotation of the female roll  204  and a selected one of the male rolls  202   a  and  202   b  in an operative position thereof. The male rolls  202   a  and  202   b  are positioned relative to the female roll  204  for movement from an inoperative to an operative position, e.g., through use of linear actuators (indicated by arrows  236  and  238 , respectively) in which the web engaging edges  206   a  of the selected one of the male rolls  202   a  and  202   b  extend into one of the two pockets  212  in the female roll  204  to a predetermined depth and are closely spaced from the web supporting edge  214  of the pocket by a distance permitting the web engaging edges  206   a  to overstrain the web  210  to weaken selected areas without contacting the web supporting edge  214 . Still additionally, the male rolls  202   a  and  202   b  each have their respective perforating elements  206  located at a circumferential position where they will be received within a different one of the two pockets  212  in the female roll  204  to thereby be able to produce two different perforation pattern formats when they are moved from the inoperative to the operative position relative to the female roll  204 . 
     In this manner, the web engaging edges  206   a  of the perforating elements  206  on each of the male rolls  202   a  and  202   b  is able to cooperate with the web supporting edge  214  of one of the two pockets  212  in the female roll  204 . They are arranged to permit the web engaging edges  206   a  to overstrain the web  210  in a manner producing the two different perforation pattern formats, i.e., they are able to produce two different sheet lengths on the web  210 . As mentioned, the male rolls  202   a  and  202   b  are each movable between an inoperative and an operative position relative to the female roll  204  to thereby produce a desired one of the two different perforation pattern formats. 
     While not specifically shown, it will be understood that in each of the two embodiments discussed above, a selected perforation pattern or design can be formed which includes perforations extending not only in the cross direction, but also extending in the machine direction. 
     In a non-limiting form illustrated in  FIG. 10 , the apparatus  200  can employ perforating elements  206  and pockets  212  extending generally parallel to the rotational axes of the male and female rolls  202  and  204 , respectively, and also generally about the circumference of the male and female rolls  202  and  204 , respectively, to form both cross and machine direction perforations. 
     Referring to  FIG. 9 , a single sheet  128  formed on a web  122  by the apparatus  200  and having an embossed or printed indicia or aesthetic pattern  130  is illustrated. The single sheet  128  has a shaped perforation pattern  133  extending generally in the cross direction which may complement, register with, or match the indicia or aesthetic pattern  130 , if desired. As shown, the contours of the perforation pattern  133  form a chevron shape which is complementary to the indicia or aesthetic pattern  130  by appropriate arrangement of the perforating elements  206 . An exemplary but non-limiting apparatus and process for registering repeating lines of perforation  132  that are formed in web  122  with the indicia or aesthetic pattern  130  are disclosed in U.S. Pat. Nos. 7,222,436 and 7,089,854. 
     The web  122  may be formed of paper or a like material having one or more plies and having a first side  122   a  and a second side  122   b . The web  122  may include a plurality of spaced apart and repeating lines of perforation  132 . These spaced apart and repeating lines of perforation  132  may either be linear or nonlinear like the shaped perforation patterns  133  in  FIG. 9 . 
     As shown in  FIG. 9 , the repeating lines of perforation  132  may comprise a plurality of individual perforations  134  extending substantially from the first side  122   a  to the second side  122   b  of the web  122 . Each one of the plurality of individual perforations  134  is selectively located in relation to the adjacent ones of the individual perforations  134 . In this manner, a selected perforation design such as the shaped perforation patterns  133  is provided for each of the repeating lines of perforation  132  which are formed along the web  122  by the apparatus  200 . 
     Still referring to  FIG. 9 , the sheets such as  128  produced on a web by the apparatus  200  may be formed in such manner that each of the repeating lines of perforation such as  132  is selectively located relative to adjacent ones of the repeating lines of perforation to define a selected perforation pattern format or sheet length. This can be done using a single male roll  202  by varying the diameter of the roll, or locating two or more sets of perforating elements  206  about the circumference of the roll as shown in  FIG. 1 . In other words, the spacing or distance between the lines of perforation such as  132  which extend generally in the cross direction of a web such as  122  to thereby define a sheet such as  128  on the web may be selected and varied as described in order to form a web product having a desired perforation pattern format or sheet length. 
     From the foregoing, it will be understood that the apparatus  200  may produce repeating lines of perforation comprising a plurality of individual web overstrain points. The plurality of individual web overstrain points produced with the apparatus  200  form the corresponding individual perforations such as  134  which may extend from the first side such as  122   a  to the second side such as  122   b  of a web such as  122  wherein each one of the plurality of individual web overstrain points is selectively located in relation to adjacent ones of the individual web overstrain points. In this manner, the lines of perforation such as  132  are able to form a selected perforation pattern  133  produced by suitably locating the perforating elements  206 . Providing a line of perforation  132  as a plurality of individual web overstrain points extending in the “Z”-direction can provide web  122  with several benefits over those perforations provided by the prior art. By way of non-limiting example, displacing individual fibers of web  122  out of plane can make the lines of perforation more visible to an end user and can be used as a dispensing aid. Additionally, displacing individual fibers of web  122  out of plane can provide more open area proximate to the perforation thereby allowing the use of optical sensors to detect perforations in the web  122  during manufacturing to assist in quality control. 
     As previously discussed, the sheets such as  128  which are produced by the apparatus  200  may have an embossed or printed aesthetic pattern such as  130  which can be produced in any conventional manner. The selected perforation pattern  133  which is comprised of the perforations such as  134  formed by the plurality of individual web overstrain points may complement, register with, or match the embossed or printed aesthetic pattern such as  130 . In addition, the contours of the perforation pattern  133  may be made to take virtually any shape due to the ability to locate each of the perforating elements  206  on the male roll  202  in any desired position. 
     In one non-limiting embodiment, the web  122  is presented to the consumer as a convolutely wound or rolled paper product. Such a product is suitable for use as paper towels, bath tissue and the like and may have a length in the machine direction of at least 500 inches and most preferably up to at least about 1000 inches. A chop-off cut may be used to terminate one convolutely wound or rolled paper product and start the next product during manufacture. 
     To achieve the foregoing, the apparatus  200  may further include a chop-off roll  36  and a bedroll  38  downstream of the male roll  202  and female roll  204  to form a chop-off in the manner illustrated and described in U.S. Pat. No. 7,222,436. The perforation pattern formed by the male and female rolls may be linear or non-linear and may or may not extend perpendicular to the machine direction of the web  122 . The chop-off may also take various forms although in one non-limiting embodiment it may be shaped rather than straight, e.g., and by way of example only, the chop-off may be chevron shaped, i.e., shaped like the perforation pattern  133  in  FIG. 9 . 
     As discussed above,  FIG. 9  illustrates lines of perforations  132  that may advantageously take the form of a shaped perforation pattern  133 . However, the chop-off roll may be formed so only the chop-off is shaped in the event the lines of perforation  132  extend perpendicular to the machine direction of the web. In this manner, the chop-off may assist the consumer to begin removal of sheets from an exposed end of the convolutely wound or rolled perforated product. 
     In other words, the chop-off cut at the exposed end of the wound or rolled product such as paper towels, bath tissue, and the like may have the same or a similar shape or design as the lines of perforation  132 , or it may have an entirely different shape, e.g., a chevron, by appropriately forming the chop-off roll to provide the desired shape at the end of the last sheet formed on the convolutely wound or rolled perforated product. i.e., the first sheet removed by the consumer. 
     In a specialized application, the male roll  202  may be formed to have two sets of perforating elements  206  wherein one set produces a perforation pattern that is linear and orthogonal to the machine direction of the web  122  and the other set produces a perforation pattern that is shaped. It is also possible for both of the two sets of perforating elements  206  to be shaped but to have different shapes and/or for each of the two sets to be formed on a different male roll  202  in operative association with the same female roll  204 . Depending upon size limitations, it will be appreciated that still other sequences of perforation patterns can be formed by providing two or more sets of perforating elements on two or more male rolls  202  to provide repeating cycles of different perforation patterns in a convolutely wound or rolled paper product. 
     While not specifically shown, it will be understood that in the embodiments discussed above, a selected perforation pattern or design can be formed on a web which includes perforations extending not only in the cross direction, but also extending in the machine direction. As will be appreciated, this can be achieved by appropriately locating the perforating elements  206  on the male roll  202  in cooperative alignment with corresponding pocket(s)  212  in the female roll  204 . In a non-limiting form, the perforating elements  206  may be formed to extend both generally parallel to the rotational axis of the male roll  202 , and generally about the circumference of the male roll  202 . In this embodiment, the female roll  204  will have correspondingly located pockets  212  whereby all of the perforating elements  206  on the male roll  202  are in alignment with a pocket in the female roll  204  to be received therein. 
     With regard to the foregoing, and referring to  FIG. 10 , the male roll  202  may be formed to have perforating elements  206  extending in both the cross direction and the machine direction to thereby mechanically perforate the web  122  in both the cross direction and the machine direction. The male roll  202  may also be used to perforate the web  122  in such manner that some or all of the resulting perforation design is linear and/or non-linear in shape. Referring again to  FIG. 10 , the male roll  202 , as illustrated, has perforating elements located to mechanically perforate the web  122  in both the cross direction and the machine direction such that the resulting perforation design is non-linear in both the cross direction and the machine direction. 
     Referring to  FIG. 9A , a single sheet  128 ′ is illustrated when produced with a male roll  202  having the perforating elements  206  extend non-linearly in both the cross direction and the machine direction. The single sheet  128 ′ as illustrated has a perforation pattern  133 ′ formed by non-linear lines of perforation  132   a ′ extending generally in the cross direction and a non-linear line of perforations  132 W extending generally in the machine direction. As will be appreciated, the contours of the lines of perforation  132   a ′ and  132   b ′ can take virtually any form and/or location by appropriate arrangement of the perforating elements  206  on the male roll  202 . 
     In addition to the foregoing, the various embodiments illustrated and described result in improved reliability and lower manufacturing costs while at the same time making it possible to form virtually any desired perforation pattern or design. 
     In all of the foregoing embodiments and configurations, it will be understood that since the webs may be transported along a path relative to the disclosed apparatus components by a device which may comprise a conventional web rewinder of a type well known in the art, the details of the rewinder and the manner in which it transports the web have not been set forth. Furthermore, the details of the web rewinder are not needed to understand the unique features of the embodiments and configurations disclosed herein and the manner in which they function. Similarly, it will be understood that the details need not be set forth for the controllers, motors, and associated gearing suitable for controlling and driving the various perforating, embossing, and/or printing rolls nor for the controllers for controlling the printing of non-contact printing devices such as inkjet printers and laser printers because they are all well known in the art. 
     With regard to non-limiting embodiments utilizing multiple rolls, cylinders or blades, it will be understood that they can utilize linear actuators and/or similar components for purposes of engaging and disengaging the various rolls, cylinders and/or similar components in a manner well known to those skilled in the art. 
     “Fibrous structure” as used herein means a structure that comprises one or more fibrous elements. In one example, a fibrous structure according to the present invention means an association of fibrous elements that together form a structure capable of performing a function. 
     The fibrous structures of the present invention may be homogeneous or may be layered. If layered, the fibrous structures may comprise at least 2 and/or at least 3 and/or at least 4 and/or at least 5 and/or at least 6 and/or at least 7 and/or at least 8 and/or at least 9 and/or at least 10 to about 25 and/or to about 20 and/or to about 18 and/or to about 16 layers. 
     In one example, the fibrous structures of the present invention are disposable. For example, the fibrous structures of the present invention are non-textile fibrous structures. In another example, the fibrous structures of the present invention are flushable such as bath paper. 
     Non-limiting examples of processes for making fibrous structures include known wet-laid papermaking processes, air-laid papermaking processes and wet, solution and dry filament spinning processes that are typically referred to as nonwoven processes. Further processing of the fibrous structure may be carried out such that a finished fibrous structure is formed. For example, in typical papermaking processes, the finished fibrous structure is the fibrous structure that is wound on the reel at the end of papermaking. The finished fibrous structure may subsequently be converted into a finished product, e.g. a sanitary tissue product. 
     “Fibrous element” as used herein means an elongate particulate having a length greatly exceeding its average diameter, i.e. a length to average diameter ratio of at least about 10. A fibrous element may be a filament or a fiber. In one example, the fibrous element is a single fibrous element rather than a yarn comprising a plurality of fibrous elements. 
     The fibrous elements of the present invention may be spun from polymer melt compositions via suitable spinning operations, such as meltblowing and/or spunbonding and/or they may be obtained from natural sources such as vegetative sources, for example trees. 
     The fibrous elements of the present invention may be monocomponent and/or multicomponent. For example, the fibrous elements may comprise bicomponent fibers and/or filaments. The bicomponent fibers and/or filaments may be in any form, such as side-by-side, core and sheath, islands-in-the-sea and the like. 
     “Filament” as used herein means an elongate particulate as described above that exhibits a length of greater than or equal to 5.08 cm (2 in.) and/or greater than or equal to 7.62 cm (3 in.) and/or greater than or equal to 10.16 cm (4 in.) and/or greater than or equal to 15.24 cm (6 in.). 
     Filaments are typically considered continuous or substantially continuous in nature. Filaments are relatively longer than fibers. Non-limiting examples of filaments include meltblown and/or spunbond filaments. Non-limiting examples of polymers that can be spun into filaments include natural polymers, such as starch, starch derivatives, cellulose, such as rayon and/or lyocell, and cellulose derivatives, hemicellulose, hemicellulose derivatives, and synthetic polymers including, but not limited to thermoplastic polymer filaments, such as polyesters, nylons, polyolefins such as polypropylene filaments, polyethylene filaments, and biodegradable thermoplastic fibers such as polylactic acid filaments, polyhydroxyalkanoate filaments, polyesteramide filaments and polycaprolactone filaments. 
     “Fiber” as used herein means an elongate particulate as described above that exhibits a length of less than 5.08 cm (2 in.) and/or less than 3.81 cm (1.5 in.) and/or less than 2.54 cm (1 in.). 
     Fibers are typically considered discontinuous in nature. Non-limiting examples of fibers include pulp fibers, such as wood pulp fibers, and synthetic staple fibers such as polypropylene, polyethylene, polyester, copolymers thereof, rayon, glass fibers and polyvinyl alcohol fibers. 
     Staple fibers may be produced by spinning a filament tow and then cutting the tow into segments of less than 5.08 cm (2 in.) thus producing fibers. 
     In one example of the present invention, a fiber may be a naturally occurring fiber, which means it is obtained from a naturally occurring source, such as a vegetative source, for example a tree and/or plant. Such fibers are typically used in papermaking and are oftentimes referred to as papermaking fibers. Papermaking fibers useful in the present invention include cellulosic fibers commonly known as wood pulp fibers. Applicable wood pulps include chemical pulps, such as Kraft, sulfite, and sulfate pulps, as well as mechanical pulps including, for example, groundwood, thermomechanical pulp and chemically modified thermomechanical pulp. Chemical pulps, however, may be preferred since they impart a superior tactile sense of softness to tissue sheets made therefrom. Pulps derived from both deciduous trees (hereinafter, also referred to as “hardwood”) and coniferous trees (hereinafter, also referred to as “softwood”) may be utilized. The hardwood and softwood fibers can be blended, or alternatively, can be deposited in layers to provide a stratified web. Also applicable to the present invention are fibers derived from recycled paper, which may contain any or all of the above categories of fibers as well as other non-fibrous polymers such as fillers, softening agents, wet and dry strength agents, and adhesives used to facilitate the original papermaking. 
     In addition to the various wood pulp fibers, other cellulosic fibers such as cotton linters, rayon, lyocell and bagasse fibers can be used in the fibrous structures of the present invention. The fibrous structure or material of the web products which are the subject of this invention may be a single-ply or a multi-ply fibrous structure suitable for being converted into a through air dried perforated product. 
     With regard to the web products which are the subject of this invention, they may be referred to as “sanitary tissue products” which, as used herein, means a soft, low density (i.e. &lt;about 0.15 g/cm 3 ) web useful as a wiping implement for post-urinary and post-bowel movement cleaning (bath tissue), for otorhinolaryngological discharges (facial tissue), and multi-functional absorbent and cleaning uses (absorbent towels). The sanitary tissue products may be convolutely wound or rolled upon itself about a core or without a core to form a sanitary tissue product roll. Such product rolls may comprise a plurality of connected, but perforated sheets of fibrous structure, that are separably dispensable from adjacent sheets. 
     In one example, the sanitary tissue products of the present invention comprise fibrous structures according to the present invention. 
     “Basis Weight” as used herein is the weight per unit area of a sample reported in lbs/3000 ft 2  or g/m 2 . The sanitary tissue products of the present invention may have a Basis Weight of greater than 15 g/m 2  (9.2 lbs/3000 ft 2 ) to about 120 g/m 2  (73.8 lbs/3000 ft 2 ) and/or from about 15 g/m 2  (9.2 lbs/3000 ft 2 ) to about 110 g/m 2  (67.7 lbs/3000 ft 2 ) and/or from about 20 g/m 2  (12.3 lbs/3000 ft 2 ) to about 100 g/m 2  (61.5 lbs/3000 ft 2 ) and/or from about 30 (18.5 lbs/3000 ft 2 ) to 90 g/m 2  (55.4 lbs/3000 ft 2 ). In addition, the sanitary tissue products of the present invention may exhibit a basis weight between about 40 g/m 2  (24.6 lbs/3000 ft 2 ) to about 120 g/m 2  (73.8 lbs/3000 ft 2 ) and/or from about 50 g/m 2  (30.8 lbs/3000 ft 2 ) to about 110 g/m 2  (67.7 lbs/3000 ft 2 ) and/or from about 55 g/m 2  (33.8 lbs/3000 ft 2 ) to about 105 g/m 2  (64.6 lbs/3000 ft 2 ) and/or from about 60 (36.9 lbs/3000 ft 2 ) to 100 g/m 2  (61.5 lbs/3000 ft 2 ). 
     Sanitary tissue products of the present invention may exhibit a Total Dry Tensile value of less than about 3000 g/76.2 mm and/or less than 2000 g/76.2 mm and/or less than 1875 g/76.2 mm and/or less than 1850 g/76.2 mm and/or less than 1800 g/76.2 mm and/or less than 1700 g/76.2 mm and/or less than 1600 g/76.2 mm and/or less than 1560 g/76.2 mm and/or less than 1500 g/76.2 mm to about 450 g/76.2 mm and/or to about 600 g/76.2 mm and/or to about 800 g/76.2 mm and/or to about 1000 g/76.2 mm. In yet another example, the sanitary tissue products, for example single-ply, embossed sanitary tissue products, exhibit a Total Dry Tensile of less than about 1560 g/76.2 mm and/or less than 1500 g/76.2 mm and/or less than 1400 g/76.2 mm and/or less than 1300 g/76.2 mm and/or to about 450 g/76.2 mm and/or to about 600 g/76.2 mm and/or to about 800 g/76.2 mm and/or to about 1000 g/76.2 mm. 
     The sanitary tissue products of the present invention may exhibit an initial Total Wet Tensile Strength value of less than 600 g/76.2 mm and/or less than 450 g/76.2 mm and/or less than 300 g/76.2 mm and/or less than about 225 g/76.2 mm. 
     In accordance with the present invention, the web is formed of paper or a like material having one or more plies wherein the material is strong enough to form the wound or rolled product having repeating lines of perforation but weak enough to separate a selected sheet from the remainder of the wound or rolled product. The Perforation Tensile Strength value for sanitary tissue products such as paper towel products, bath tissue products, and the like can be determined by the Perforation Tensile Strength Method described infra. 
     A single ply paper towel product of the present invention may have a Perforation Tensile Strength value of less than about 150 g/in (1.97 g/76.2 mm), preferably less than about 120 Win (1.57 g/76.2 mm), even more preferably less than about 100 g/in (1.31 g/76.2 mm), and yet more preferably less than about 50 Win (0.66 g/76.2 mm). A two ply paper towel product of the present invention may have a Perforation Tensile Strength value of less than about 170 g/in (2.23 g/76.2 mm), more preferably less than about 160 g/in (2.10 g/76.2 mm), even more preferably less than about 150 Win (1.97 g/76.2 mm), yet more preferably less than about 100 Win (1.31 g/76.2 mm), even yet more preferably less than about 60 Win (0.79 g/76.2 mm), and most preferably less than about 50 Win (0.66 g/76.2 mm) A two-ply bath tissue product of the present invention may have a Perforation Tensile Strength value of less than about 160 Win (2.10 g/76.2 mm), preferably less than about 150 g/in (1.97 g/76.2 mm), even more preferably less than about 120 Win (1.57 g/76.2 mm), yet more preferably less than about 100 Win (1.31 g/76.2 mm), and most preferably less than about 65 Win (0.85 g/76.2 mm). 
     The sanitary tissue products of the present invention may exhibit a Density (measured at 95 Win) of less than about 0.60 g/cm 3  and/or less than about 0.30 g/cm 3  and/or less than about 0.20 g/cm 3  and/or less than about 0.10 g/cm 3  and/or less than about 0.07 g/cm 3  and/or less than about 0.05 g/cm 3  and/or from about 0.01 g/cm 3  to about 0.20 g/cm 3  and/or from about 0.02 g/cm 3  to about 0.10 g/cm 3 . 
     “Density” as used herein is calculated as the quotient of the Basis Weight expressed in grams per square meter divided by the Caliper expressed in microns. The resulting Density is expressed as grams per cubic centimeters (g/cm 3  or g/cc). Sanitary tissue products of the present invention may have Densities greater than 0.05 g/cm 3  and/or greater than 0.06 g/cm 3  and/or greater than 0.07 g/cm 3  and/or less than 0.10 g/cm 3  and/or less than 0.09 g/cm 3  and/or less than 0.08 g/cm 3 . In one example, a fibrous structure of the present invention exhibits a density of from about 0.055 g/cm 3  to about 0.095 g/cm 3 . 
     “Embossed” as used herein with respect to a fibrous structure means a fibrous structure that has been subjected to a process which converts a smooth surfaced fibrous structure to a decorative surface by replicating a design on one or more emboss rolls, which form a nip through which the fibrous structure passes. Embossed does not include creping, microcreping, printing or other processes that may impart a texture and/or decorative pattern to a fibrous structure. In one example, the embossed fibrous structure comprises deep nested embossments that exhibit an average peak of the embossment to valley of the embossment difference of greater than 600 μm and/or greater than 700 μm and/or greater than 800 μm and/or greater than 900 μm as measured using MicroCAD. 
     Test Methods 
     Unless otherwise specified, all tests described herein including those described under the Definitions section and the following test methods are conducted on samples that have been conditioned in a conditioned room at a temperature of 73° F.±4° F. (about 23° C.±2.2° C.) and a relative humidity of 50%±10% for 2 hours prior to the test. If the sample is in roll form, remove the first 35 to about 50 inches of the sample by unwinding and tearing off via the closest perforation line, if one is present, and discard before testing the sample. All plastic and paper board packaging materials must be carefully removed from the paper samples prior to testing. Discard any damaged product. All tests are conducted in such conditioned room. 
     a. Perforation Tensile Strength Test Method 
     Principle: 
     A strip of sample of known width is cut so that a product perforation line passes across the strip perpendicularly in the narrow (width) dimension about equal distance from either end. The sample is placed in a tensile tester in the normal manner and then tensile strength is determined. The point of failure (break) will be the perforation line. The strength of the perforation is reported in grams. 
     Apparatus: 
     Conditioned Room: Temperature and humidity controlled within the following limits: 
     Temperature—73° F.±2° F. (23° C.±1° C.) 
     Relative Humidity—50% (±2%) 
     Sample Cutter: JDC Precision Sample Cutter, 1 inch (25.4 mm) wide double edge cutter, Model JDC-1-12 (Recommended), or Model 1 JDC-1-10; equipped with a safety shield, P&amp;G drawing No. A-PP-421; Obtain the cutter from Thwing Albert Instrument Company, 10960 Dutton Road, Philadelphia, Pa. 19154
 
Cutting Die: (Only for use in cutting samples with the Alpha Cutter) 1.0 inch wide×8.0 inches (25.4×203.2 mm) long on a ¾ inch (19 mm) base; Acme Steel Rule, Die Corp., 5 Stevens St., Waterbury, Conn., 06714, or equivalent. The die must be modified with soft foam rubber insert material.
 
Soft foam rubber insert material: Polyurethan, ¼ in. (6.3 mm) thick, P-17 Crofleon, Inc., 1801 West Fourth St., Marion, Ind. 46952, or equivalent.
 
Tensile Tester: Refer to Analystical Method GCAS 58007265 “Testing and Calibration of Instruments—the Tensile Tester”
 
Tensile Tester Grips: Thwing-Albert TAPPI air grips 00733-95
 
Calibration Weights: Refer to Analytical Method GCAS 58007265 “Testing and Calibration of Instruments—The Tensile Tester”
 
Paper Cutter.
 
Rule: Ruler to check gauge length, 6 inch (152.4 mm) metal, with 0.01 inch (0.25 mm) graduations. Cat. #C305R-6, L.S. Starrett Co., Athel, Mass. 01331, or equivalent.
 
Resealable Plastic Bags: Recommended size 26.8 cm×27.9 cm.
 
Sample Preparation:
 
     For this method, a usable unit is described as one finished product unit regardless of the number of plies. 
     Condition the rolls or usable units of product, with wrapper or packaging materials removed, in a room conditioned at 50±2% relative humidity, 73° F.±2° F. (23° C.±1° C.) for a minimum of two hours. For new roll remove at least the outer 8-10 usable units of product and discard. Do not test samples with defects such as perforation skips, wrinkles, tears, incomplete perfs, holes, etc. Replace with other usable unites free of such defects. For roll wipes, condition in sealed package for a minimum of two hours. 
     Towels: 
     At all times handle the samples in such a manner that the perforations between the usable units are not damaged or weakened. Prepare the samples for testing using one of the two methods (i.e., a continuous five-usable unit-strip or four two-usable unit strips) described below. For usable units having a length (MD) greater than 8 inches (203.2 mm), either approach may be used in preparing the sample. For usable units having a length (MD) less than or equal to 8 inches (203.2 mm), use only the approach requiring strips of two towels to prepare the samples for testing. 
     A. Continuous Strip of 5 Towels
         For the continuous strip of five towels, fold the second towel approximately in the center so that the perforation between towels one and two lies exactly on top of the perforation between towels two and three. Continue folding the remaining usable units until the four perforations contained in the strip of five towels are exactly coincident in a stack. Using the paper cutter, make cuts parallel to the usable units a minimum of 7 inches (177.8 mm) wide by towel width long with the perforation aligned, parallel to the long dimension of the stack and approximately in its center.       

     B. Strip of 2 Towels
         Where four pairs of usable units have been taken for the samples, stack these usable unit pairs, one on the other, so that their perforations are exactly coincident. Proceed as described above to cut this stack of usable units so that the coincident perforations are in the approximate middle of a 7 inch (177.8 mm) minimum by roll width stack and parallel to the stack long dimension.
 
Bath Tissue/Roll Wipes:
       

     At all times the sample should be handled in such a manner that perforations between usable units are not damaged or weakened. Remove four strips of two usable units each whether consecutively or from various positions in the sample. Lay the four strips, one on top of the other, being very careful that the perforations between the usable unit pairs are exactly coincident. Note: For roll wipes place the remaining wipes in a resealable plastic bag and seal bag. Test roll wipes immediately. 
     Using either a JDC cutter or a cutting die and Alpha cutter, cut a one-inch (25.4 mm) wide sample strip four finished product units thick in the machine direction of the stack of four thicknesses of product obtained by one of the above techniques ( FIG. 02 ). The result will be a strip of sample four finished product units thick, one-inch (25.4 mm) wide by a minimum of seven inches (177.8 mm) long, having a perforation line perpendicular to the 8 inch (203.2 mm) dimension of the strip and in its approximate center. 
     Reference Table 1 for preparation and Tensile Tester settings. 
                     TABLE 1                  Perforation Strength Preparation                                     Number of   Number of               Sample   product units per   replicates per       Tensile       Description   test   sample   Load divider   grip type               Towel   1   4   1   Flat       Bath   1   4   1   Flat       Tissue/Roll       Wipes                    
Operation:
 
     Reject results from any strip where the sample is not completely broken, preparing a replacement strip for testing as described in Sample Preparation (see examples below). 
     Towel (Work-to-Tear and Perforation Stretch): 
     Clamp the sample in the grips of a properly calibrated tensile tester. Determine the tensile strength and perforation stretch of each of the four strips of each sample. Each strip should break completely at the perforation. In cases where an Intelect 500 Tensile Tester is employed, a sensitivity of 0 g should be used to achieve this. 
     Bath Tissue/Roll Wipes (Perforation Strength and/or Work-to-Tear and Perforation Stretch): 
     Clamp the sample in the grips of a properly calibrated tensile tester. Determine the tensile strength of each of the four strips of each sample and/or determine the tensile strength and perforation stretch of each of the four strips of each sample. Each strip should break at the perforation. In cases where an Intelect 500 Tensile Tester is employed, a sensitivity of 0 g should be used to achieve this. 
     Calculations: 
     Since some tensile testers incorporate computer capabilities that support calculations, it may not be necessary to apply all of the following calculations to the test results. For example, the Thwing-Albert Intelect II STD tensile tester can be operated through its averaging mode for reporting the average perforation tensile strength and average perforation stretch. 
     Perforation Tensile Strength (All Products): 
     The perforation tensile is determined by dividing the sum of the perforation tensile strengths of the product by the number of strips tested. 
               Perforation   ⁢           ⁢   Tensile     =       Sum   ⁢           ⁢   of   ⁢           ⁢   tensile   ⁢           ⁢   results   ⁢           ⁢   for   ⁢           ⁢   strips   ⁢           ⁢   tested   ⁢           ⁢     (   grams   )         Number   ⁢           ⁢   of   ⁢           ⁢   strips   ⁢           ⁢   tested             
Perforation Stretch:
 
     The perforation stretch is determined by dividing the sum of the perforation stretch readings of the product by the number of strips tested. 
               Perforation   ⁢           ⁢   Stretch     =       Sum   ⁢           ⁢   of   ⁢           ⁢   stretch   ⁢           ⁢   results   ⁢           ⁢   for   ⁢           ⁢   strips   ⁢           ⁢   tested   ⁢           ⁢     (   %   )         Number   ⁢           ⁢   of   ⁢           ⁢   strips   ⁢           ⁢   tested                       “   Work   ”     ⁢     -     ⁢   to   ⁢     -     ⁢   Tear   ⁢           ⁢   Factor   ⁢     :       _                 Work   ⁢     -     ⁢   to   ⁢     -     ⁢   tear   ⁢           ⁢   Factor   ⁢           ⁢     (   WTTF   )       =       Perforation   ⁢           ⁢   Tensile   ×   Perforation   ⁢           ⁢   stretch     100                   Perforation   ⁢           ⁢   Tensile   ⁢           ⁢   to   ⁢           ⁢   MD   ⁢           ⁢   Tensile   ⁢           ⁢   Ratio   ⁢           ⁢     (   PERFMD   )     ⁢           ⁢     (     Tissue   ⁢           ⁢   only     )     ⁢     :       _               PERFMD   =       Perforation   ⁢           ⁢   Tensile       Average   ⁢           ⁢   Tensile   ⁢           ⁢   Strength   ⁢           ⁢     (   MD   )               
b. Tensile Strength Test Method
 
     Remove five (5) strips of four (4) usable units (also referred to as sheets) of fibrous structures and stack one on top of the other to form a long stack with the perforations between the sheets coincident. Identify sheets 1 and 3 for machine direction tensile measurements and sheets 2 and 4 for cross direction tensile measurements. Next, cut through the perforation line using a paper cutter (JDC-1-10 or JDC-1-12 with safety shield from Thwing-Albert Instrument Co. of Philadelphia, Pa.) to make 4 separate stacks. Make sure stacks 1 and 3 are still identified for machine direction testing and stacks 2 and 4 are identified for cross direction testing. 
     Cut two 1 inch (2.54 cm) wide strips in the machine direction from stacks 1 and 3. Cut two 1 inch (2.54 cm) wide strips in the cross direction from stacks 2 and 4. There are now four 1 inch (2.54 cm) wide strips for machine direction tensile testing and four 1 inch (2.54 cm) wide strips for cross direction tensile testing. For these finished product samples, all eight 1 inch (2.54 cm) wide strips are five usable units (sheets) thick. 
     For the actual measurement of the tensile strength, use a Thwing-Albert Intelect II Standard Tensile Tester (Thwing-Albert Instrument Co. of Philadelphia, Pa.). Insert the flat face clamps into the unit and calibrate the tester according to the instructions given in the operation manual of the Thwing-Albert Intelect II. Set the instrument crosshead speed to 4.00 in/min (10.16 cm/min) and the 1st and 2nd gauge lengths to 2.00 inches (5.08 cm). The break sensitivity is set to 20.0 grams and the sample width is set to 1.00 inch (2.54 cm) and the sample thickness is set to 0.3937 inch (1 cm). The energy units are set to TEA and the tangent modulus (Modulus) trap setting is set to 38.1 g. 
     Take one of the fibrous structure sample strips and place one end of it in one clamp of the tensile tester. Place the other end of the fibrous structure sample strip in the other clamp. Make sure the long dimension of the fibrous structure sample strip is running parallel to the sides of the tensile tester. Also make sure the fibrous structure sample strips are not overhanging to the either side of the two clamps. In addition, the pressure of each of the clamps must be in full contact with the fibrous structure sample strip. 
     After inserting the fibrous structure sample strip into the two clamps, the instrument tension can be monitored. If it shows a value of 5 grams or more, the fibrous structure sample strip is too taut. Conversely, if a period of 2-3 seconds passes after starting the test before any value is recorded, the fibrous structure sample strip is too slack. 
     Start the tensile tester as described in the tensile tester instrument manual. The test is complete after the crosshead automatically returns to its initial starting position. When the test is complete, read and record the following with units of measure: 
     Peak Load Tensile (Tensile Strength) (g/in) 
     Test each of the samples in the same manner, recording the above measured values from each test. 
     Calculations: 
     Total Dry Tensile (TDT)=Peak Load MD Tensile (g/in)+Peak Load CD Tensile (g/in) 
     Tensile Ratio=Peak Load MD Tensile (g/in)/Peak Load CD Tensile (g/in) 
     Table 2 below tabulates some measured tensile values of various commercially available fibrous structures. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Total and Perforation Tensile Strength Values for Various Substrates 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                 Per- 
               
               
                   
                   
                   
                   
                 Total Dry 
                 foration 
               
               
                   
                   
                   
                   
                 Tensile 
                 Tensile 
               
               
                   
                 # of 
                   
                   
                 Strength 
                 Strength 
               
               
                 Fibrous Structure 
                 Plies 
                 Embossed 
                 TAD 1   
                 g/76.2 mm 
                 g/in 
               
               
                   
               
               
                 Charmin ® Basic 
                 1 
                 N 
                 Y 
                 1486 
                   
               
               
                 Charmin ® Basic 
                 1 
                 N 
                 Y 
                 1463 
               
               
                 Charmin ® Ultra Soft 
                 2 
                 N 
                 Y 
                 1457 
                 171 
               
               
                 Charmin ® Ultra 
                 2 
                 Y 
                 Y 
                 2396 
                 190 
               
               
                 Strong 
               
               
                 Cottonelle ® 
                 1 
                 N 
                 Y 
                 1606 
               
               
                 Cottonelle ® 
                 1 
                 N 
                 Y 
                 1389 
               
               
                 Cottonelle ® Ultra 
                 2 
                 N 
                 Y 
                 1823 
                 174 
               
               
                 Cottonelle ® Ultra 
                 2 
                 N 
                 Y 
                 2052 
               
               
                 Scott ® 1000 
                 1 
                 Y 
                 N 
                 1568 
                 271 
               
               
                 Scott ® Extra Soft 
                 1 
                 N 
                 Y 
                 1901 
                 176 
               
               
                 Scott ® Extra Soft 
                 1 
                 Y 
                 Y 
                 1645 
                 223 
               
               
                 Bounty ® Basic 
                 1 
                 N 
                 Y 
                 3827 
               
               
                 Bounty ® Basic 
                 1 
                 Y 
                 Y 
                 3821 
               
               
                 Viva ® 
                 1 
                 N 
                 Y 
                 2542 
                 153 
               
               
                 Quilted Northern ® 
                 3 
                 Y 
                 N 
                 1609 
                 166 
               
               
                 Ultra Plush 
               
               
                 Quilted Northern ® 
                 2 
                 Y 
                 N 
                 1296 
               
               
                 Ultra 
               
               
                 Quilted Northern ® 
                 2 
                 Y 
                 N 
                 1264 
               
               
                 Angel Soft ® 
                 2 
                 Y 
                 N 
                 1465 
                 166 
               
               
                   
               
               
                   1 “TAD” as used herein means through air dried. 
               
            
           
         
       
     
     With regard to the foregoing parametric values, they are non-limiting examples of physical property values for some fibrous structures or materials that can be utilized for sanitary tissue products that can be formed as a wound or rolled web in accordance with the present invention. These non-limiting examples are materials which are strong enough to enable a wound or rolled web product to be formed having repeating lines of perforation defining a plurality of sheets. Further, these non-limiting examples are materials which are also weak enough to enable a consumer to separate a selected one of the sheets, typically the end sheet, from the remainder of the wound or rolled product by tearing along one of the lines of perforation defining the sheet. 
     The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.” 
     All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. To the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern. 
     While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.