Apparatus And Method For Centering And Spreading A Web

Abstract

A web centering and spreading processing system and related method are used to center a moving web and then spread the web in order to remove wrinkles from the web. The centering mechanism, in one example, has a centering roller that receives the wrinkles web. The outer edges of the web, which tend to be uneven and not centered, are detected and a signal is sent to the centering roller to move the web laterally and thereby center the web. The centered web, which is substantially centered but not necessarily precisely centered, moves to a spreader station that receives the web and spreads it thereby removing any wrinkles in the web. The spreader station may include a roller with a recessed center area and that has at least one set of contoured plates that move across the roller from an inner position to an outer position. The plates have gripping surfaces that grip the edges of the web and spread the web to remove the wrinkles. The plates also have an inner smooth area that, in conjunction with the recessed area, allow the inner area of the web to essentially float and thereby be spread to remove the wrinkles without binding.

Description

FIELD OF THE INVENTION

Aspects of the present disclosure involve a web processing apparatus and method. More particularly, aspects of the present disclosure involve an apparatus and method for centering and spreading a moving web.

BACKGROUND OF THE INVENTION

Many different products, such as diapers, are manufactured or produced in a web process. Generally speaking, a web might begin with some form of base material and the constituent parts of the end product are introduced into the moving web at various stations. At the end of the process, the web contains a series of end products, which are each then individually cut from the web. So, in the example of a diaper, the various constituent parts of the diaper, such as the backing, elastic waist bands, absorbent pads, etc., are arranged and fixed on the web until the web includes a series of finished diapers, which are each then cut from the web.

Any such web processing system, whether it be for diapers or otherwise, may impart wrinkles or folds into the web. Wrinkles may impart unwanted variability into the end product. For example, if a diaper web having a wrinkle in the waist band area is cut from the web, the waist band in the final diaper may have a jagged edge along the waist band. Other such unwanted variations are also possible.

As will be recognized from the discussion below, these and other problems in the art are addressed by various systems and methods set forth herein for centering a web and spreading the web to remove wrinkles and position the web for a cutting stage or other subsequent processing operation. Before explaining the disclosed embodiments in detail, it is to be understood that this disclosure is not limited in its application to the details of the particular arrangements shown. Moreover, implementations conforming to aspects of the disclosure may be set forth in different combinations and arrangements unique in their own right. Also, the terminology used herein is for the purpose of description and not of limitation.

SUMMARY OF THE INVENTION

One aspect of the present disclosure involves a method of processing a web, such as but not limited to a diaper web, that involves a processing system defining a machine center line and a cross-machine direction substantially perpendicular to the machine center line. The method receives a moving web defining a first side edge and a second side edge. The web may have wrinkles or other folds. The method further includes adjusting the web in the cross machine direction and laterally spreading the web to substantially remove the one or more wrinkles. The adjusting operation may involve detecting a difference between a first distance and a second distance, the first distance being between the first side edge and the machine center line and the second distance being between the second side edge and the machine center line. The spreading operation may involve detecting an aspect of the web indicative of a distance between the first side edge and the second side edge and controlling the laterally spreading of the web to substantially remove the one or more wrinkles as a function of the aspect of the web indicative of the distance between the first side edge and the second side edge.

Another aspect of the present disclosure involves a web processing system defining a machine center line and a cross-machine direction configured to process a moving web defining a first side edge and a second side edge. The system includes a web centering assembly comprising a centering mechanism in communication with at least one sensor configured to detect the relationship between the moving web and the machine center line. The centering mechanism is configured to receive at least one signal indicative of the relationship between the moving web and the machine center line and adjust the moving web in the cross-machine direction. The system further includes a web spreading assembly including a spreader roller defining a first circumference and a second circumference substantially equal to the first circumference, and a third circumference less than the first and second circumference and positioned between the first and second circumferences. The spreader roller moveably supports a first plate and a second plate on at least a portion of the first and second circumference, respectively. The first and second plate are arranged to engage the web received from the web centering assembly in a region of the first and second edge side edges respectively, and move substantially in the cross-machine direction to spread the web.

Yet another aspect of the present disclosure involves a web spreading assembly including a spreader roller configured to receive a web. The spreader roller has an outer substantially circumferential surface defining a first circumference, a second circumference substantially equal to the first circumference, and a third circumference less than the first and second circumference and positioned between the first and second circumferences. The spreader roller moveably supports at least a first plate and second plate on at least a portion of the first and second circumference, respectively, the first and second plates arranged to engage the web and move substantially in the cross-machine direction to spread the web. The spreader roller includes a spreader mechanism coupled with the first plate and the second plate and configured to move the first and second plates substantially in the cross-machine direction. The spreader mechanism receives at least one control signal indicative of a width of the web and the spreader mechanism is configured to control an amount of movement of the first plate and the second plate in the cross-machine direction as a function of the at least one control signal. The first plate defines an outer area with a surface configured to engage the web in the region of the first side edge and further defines an inner area adjacent the outer area. The inner area has a low coefficient of friction surface configured to allow the web to freely slide of over the inner area. Similarly, the second plate defines a second outer area with a second surface configured to engage the web in the region of the second side edge. The second plate further defines a second inner area adjacent the second outer area. The second inner area has a low coefficient of friction surface configured to allow the web to freely slide over the inner area.

These and other aspects of the present disclosure are set forth in greater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representative side view of one example of a web processing system involving various web processing stations including a web centering station and a web spreading station.

FIG. 2 is a top view of a diaper web that may be processed in accordance with implementations set forth herein.

FIG. 3 is a representative view of a web having a longitudinal fold or wrinkle.

FIG. 4 is a partially exploded isometric view of one particular implementation of a web centering and spreading assembly.

FIG. 5 is an isometric view of the web centering and spreading assembly shown in FIG. 4.

FIG. 6 is an exploded rear isometric view of the web centering and spreading assembly of FIG. 4.

FIG. 7 is a rear view of the web centering and spreading mechanism of FIG. 4.

FIG. 8A is a diagram depicting a web including a wrinkle and outer edges that are not centered.

FIG. 8B is a diagram depicting the web of FIG. 8A after it has been centered such that the web still includes a wrinkle but the side edges are centered.

FIG. 8C is a diagram depicting the web of FIG. 8B after the spreading operation such that the web is centered and the wrinkle has been removed from the web.

FIG. 9 is a flowchart depicting one method of centering and spreading a web.

FIG. 10 is a representative isometric view of a web spreading roller.

FIG. 11 is an exploded isometric view of a web spreading mechanism for use in a web spreading assembly.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the present disclosure involve an apparatus and method for centering and spreading a web. In one particular implementation, the apparatus and method are deployed in a diaper manufacturing process to remove wrinkles in a diaper web before the diapers are cut from the web. A centering and web spreading assembly, in one example, involves a camber roller assembly that receives a web including some wrinkles. Due to the presence of the wrinkles, as well as other factors, the web may enter the camber roller such that the web's longitudinal center line is misaligned with the machine and associated roller center line. Additionally, the outer edges of the web may be misaligned relative to the center lines and misaligned relative to the outer edges of the camber roller (e.g., the side edges of the web are not equidistant from the outer edges of the roller). Thus, in one implementation, the camber roller has one or more edge sensors, positioned either before, after, or in both positions relative to the web entering the camber roller and may be in a feedback or a feedforward configuration. The edge sensors are configured to detect the edges of the web and adjust the camber roller to center the web on the roller, such that the outer edges of the web are substantially equidistant from the center line of the roller and/or the outer sides of the roller. The camber roller may remove some wrinkles, but is not primarily tasked with removing wrinkles from the web.

The centered web proceeds from the camber roller assembly to a spreader assembly that receives the web and spreads the web laterally (in the cross-machine direction) to remove any wrinkles in the web. The spreader assembly includes a spreader roller defining an inner circumferential area adjacent two outer circumferential areas having a slightly greater diameter than the inner area. Two pairs of spreader plates are positioned on the spreader roller, with a first pair of plates positioned on the outer area and the second pair of plates positioned about 180 degrees from the first pair and also on the outer area. A pair of spreader plates are configured to engage the web as it contacts the spreader roller, with the spreader plates initially positioned adjacent the inner reduced diameter area. As the roller rotates in the direction of the moving web, the spreader plates move outwardly relative to each other and toward the outer edge of the roller thereby spreading the web. The spreader plates each include an inner smooth area and an outer gripping area. The outer gripping area engages the outer edge region of the web, while the inner smooth area of the plate in conjunction with the reduced diameter inner area of the spreader allows the web to spread without being hindered by either the roller or a portion of the spreader plates.

In one implementation, discussed below in detail, the edge sensors have an additional role besides providing a control signal to the web centering assembly. Namely, the edge sensors also provide a control signal to the web spreading assembly. The web spreading assembly uses the control signal to control the spreader plates to impart either a greater or lesser amount of web spreading. The edge sensors detect the relative position of the web edges, which web edge positioning is a function of the degree of wrinkling of the web. A greater degree of wrinkling in the web will translate to one or both edges of the web being closer to the machine center line. Hence, before entering the spreader assembly, the effective width of the web will be more or less depending on the number of wrinkles, degree of wrinkling, among other factors. By providing the control signal to the web spreading assembly, the spreader plates may be moved to a greater or lesser extent to compensate for the presence of a greater number of wrinkles, degree of wrinkling (requiring more spreading) or a lesser number and degree of wrinkling (requiring less spreading). These implementations are discussed in greater detail below.

One example of a diaper manufacturing process that may employ a centering and spreading apparatus is schematically illustrated in FIG. 1. The diaper manufacturing process produces a continuous web 20 defining a plurality of interconnected disposable absorbent articles, such as diapers 22, that are eventually cut out of the web into individual diapers. Each diaper 22 includes an absorbent pad element or absorbent core 24, a pair of elastomeric elements or patches 26, which may be comprised of “live” synthetic or natural rubber, synthetic or natural rubber foam, elastomeric film, elastomeric nonwoven laminate, elastomeric scrim or the like, or other materials or combinations of materials commonly used for such purposes. The absorbent pad elements 24 and the elastomeric elements 26 are located intermediate a backsheet 28 and a topsheet 30.

The backsheet 28 is generally that portion of the diaper which prevents the exudates absorbed and contained therein from soiling articles which may contact the diaper, such as bedsheets and undergarments. The backsheet 28 may be impervious to liquids (e.g., urine) and include a thin plastic film. Other suitable backsheet material may include breathable materials which permit vapors to escape from the diaper while still preventing exudates from passing through the backsheet. Examples of breathable materials include woven webs, nonwoven webs, composite materials such as film-coated nonwoven webs, and microporous films.

The topsheet 30 may be compliant, soft feeling, and non-irritating to the wearer's skin. Further, at least a portion of the topsheet 30 may be liquid pervious, permitting liquids to readily penetrate through the thickness of the topsheet. The topsheet may be made of a hydrophobic material or may be treated to be hydrophobic in order to isolate the wearer's skin from liquids contained in the absorbent pad. If the topsheet is made of a hydrophobic material, at least the upper surface of the topsheet is treated to be hydrophilic so that liquids will transfer through the topsheet more rapidly. This diminishes the likelihood that body exudates will flow off the topsheet rather than being drawn through the topsheet and being absorbed by the absorbent pad. The topsheet can be rendered hydrophilic by treating it with a surfactant or by incorporating a surfactant into the topsheet. A suitable topsheet may be manufactured from a wide range of materials, such as porous foams; reticulated foams; apertured plastic films; or woven or nonwoven webs of natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polyester or polypropylene fibers), or a combination of natural and synthetic fibers. If the absorbent assemblies include fibers, the fibers may be spunbond, carded, wet-laid, meltblown, hydroentangled, or otherwise processed as is known in the art.

The continuous webs of backsheet material 28 and topsheet material 30 may be maintained under very slight tension in the machine direction (i.e., along the web longitudinally) to reduce wrinkling and to facilitate registration with the diaper assembly and converting operations until the completed diaper web is severed into discrete diapers 22.

The absorbent pad segments 24 are fed into a nip (not shown) between a pair of combining or laminating rolls 34 at regularly spaced intervals. The absorbent pads 24 may comprise any absorbent material which is generally compressible, conformable, non-irritating to the wearer's skin, and capable of absorbing and retaining liquids such as urine and other certain body exudates.

The elastomeric patches 26 may be secured to the backsheet 28, topsheet 30 or both utilizing either an intermittent bonding configuration or a substantially continuous bonding configuration. The intermittent bonding configuration may be desirable in those situations where a relatively high degree of z-direction bulking is desired in the finished product. Conversely, a continuous bonding configuration may be desirable where a relatively lower degree of z-direction bulking is desired in the finished product.

The web of backsheet material 28 is directed to a glue applicator 36. The glue or adhesive 38 may be heated or unheated. If an intermittent bonding pattern is used, the glue applicator 36 may be used to apply discrete, spaced apart spots, lines, or spirals of adhesive in the predetermined areas of the backsheet 28 where the substantially untensioned elastomeric patches 26 will be placed.

Alternatively, if a substantially continuous bonding pattern is utilized, the glue applicator may be used to apply a substantially uniform and continuous application of adhesive 38 to the backsheet 28 in those predetermined areas of the backsheet 28 where the substantially untensioned elastomeric patches 26 will be placed. Instead of using an adhesive, the backsheet 28 and/or topsheet 30 may be bonded to the elastomeric patches 26 using heat bonding, pressure bonding, ultrasonic bonding, etc. In such instances, thermal energy may, if desired, be applied to the backsheet 28 by other means well known to those skilled in the art, e.g., radiant heaters, hot air blasts, etc., to achieve a similar result.

Two rolls of elastomeric material 40 are fed under very slight (essentially “zero strain”) tension at a speed which provides the desired length of elastomeric patch 26 per diaper onto an anvil roll 42 equipped with vacuum hold down ports (not shown) at its periphery. A knife 44 makes one cut per diaper and the substantially untensioned elastomeric patches 26 travel with anvil roll 42 secured to its periphery by vacuum until they reach transfer location 46. At location 46 the elastomeric patches 26 are transferred to predetermined portions of the backsheet web 28 coinciding with adhesive 38. The transfer is sequential and the surface speed of the vacuum equipped anvil roll 42 and the backsheet web 28 are essentially equal. The backsheet web 28 with elastomeric patches 26 attached thereto at predetermined points along its length is then directed to the pair of laminating or combining rolls 34.

The continuous web of topsheet material 30 is directed to a second glue applicator 48 where a pattern of adhesive 50 is sized to substantially match the dimensions and locations of the elastomeric patches 26 on backsheet web 28. As with backsheet material 28, the pattern of adhesive applied to the topsheet material 30 may be either intermittent or substantially continuous. If desired, adhesive applicator 48 may be identical to adhesive applicator 36.

The backsheet web 28 and the topsheet web 30 and the absorbent pads 24 are brought into contact with one another at combining rolls 34. Just prior to the webs and pads coming into contact with one another, additional adhesive is applied to one or both webs by means which are, for clarity, not shown in FIG. 1. The latter adhesive secures predetermined portions of the backsheet, topsheet and absorbent pad to one another to form the diaper web 20. The fully assembled diaper web 20 may thereafter proceed through a pair of bond setting rolls 52, which may include chilling to minimize glue bleed through.

The fully assembled diaper web 20 is then directed through an activation system 54. One example of an activation system is set forth in U.S. Pat. No. 6,500,377 titled “Method and Apparatus for Activation a Moving Web,” issued Dec. 31, 2002, which is hereby incorporated by reference herein. The activation system is arranged to intermittently stretch the web laterally (i.e., in the cross-machine direction).

FIG. 2 illustrates a portion of the diaper web 20 defining one diaper 56 after it is cut from the web (bounded by vertical dashed lines) and adjacent diapers. The diaper includes the absorbent core 24, a first elastic waistband section 58 and a second elastic waistband section 60, along with the elastic side panel sections 26. When fitted to a person, the absorbent core is in the crotch region, the waistband areas are circumferentially fastened together around the user's waist, and the leg cutouts 62 (cut after the centering and spreading operations discussed below) are around the user's legs. The activation operation stretches the web in the cross-machine direction 64 generally along the waistband and the side panel areas, which activates the waistband and side panels so that the waistband and the side panels are elastically extensible after the diaper is removed from the web. In one implementation, the web is stretched in the side panel region a greater degree than it is stretched in the absorbent region. Activation causes a variable web width and also variable web tension, which can cause the web to wrinkle.

Web wrinkling sometimes involves folds 66 or wrinkles running somewhat longitudinally in the machine direction as shown in FIG. 3, which illustrates the wrinkled web before it enters a camber roller 68. The presence of wrinkles can be problematic for subsequent web processing steps. For example, in the diaper assembly process discussed herein, if the fully assembled diaper and activated web is processed in a side notch cutting tool 72A that cuts the leg notches 62 in the web 20 for each individual diaper, or in a knife tool 72B that cuts the web into individual diapers, then the presence of wrinkles can cause uneven leg notches, uneven diaper dimensions, ragged and uneven edges, among other problems. Accordingly, one aspect of the present disclosure involves an apparatus and method for spreading the web to remove wrinkles.

In a system for fabricating diapers from a web, such a spreading apparatus 70 is positioned after the activation station 54 and before any subsequent cutting stations 72, as shown in FIG. 1. Also, a web centering station 74, including camber roller 68, is positioned before the web spreading station 70 so that the web is substantially centered with respect to the machine center line before it enters the spreader assembly 70. Such a system may be used in any web processing system where lateral web spreading is desirable, whether or not to remove wrinkles from a web.

FIGS. 4 and 5 illustrate rear isometric views of one example of a web centering and spreading mechanism 76. FIG. 6 illustrates an exploded isometric view of the web centering and spreading mechanism. The web centering and spreading mechanism includes two primary components, the centering station 74 and the spreader assembly 70. The web, including wrinkles, first enters the centering station, which in one particular implementation involves a camber roller assembly (see, e.g., FIG. 4) where it is substantially centered with respect to the machine center line. From the camber roller, the web then proceeds to a set of edge sensors 78 (see, e.g., FIG. 5) that detect the outer edges of the web 80 (see FIG. 1) and provide a feedback signal to the camber roller 74 to center the web and also provide a feedforward signal to the spreader assembly 70 for adjusting the amount spreading. From the edge sensors, the web proceeds to the power spreader assembly 70 (see, e.g., FIG. 5) where any wrinkles or folds are stretched out of the web. In the example implementation shown herein, the camber roller assembly and the power spreader assembly are shown supported on a common frame. However, in a system conforming to aspects of this disclosure, the camber roller assembly, or other web centering device, and related edge sensors or other sensor types or arrangements, along with the power spreader assembly may be supported on separate frame assemblies. Additionally, other stations may be positioned between the centering station and the spreader station, and the centering station and/or the spreader station may be set forth in combination with other components, stations, or the like.

The camber roller assembly 74 is configured to center the web on the camber roller 68 such that the web will be substantially centered on the power spreader assembly. The edge sensors 78 are connected to a servo motor 82 on the camber roller assembly in a feedback configuration. The edge sensors detect each outer edge 80 of the web as it runs through the sensors and sends feedback signals to the camber roller assembly to adjust the camber roller 68 to center the web.

Referring primarily to FIGS. 4, 6 and 7, the camber roller assembly includes the camber roller 68 rotatably supported between a pair of brackets 84. The axis 86 of the camber roller is perpendicular to the machine direction (perpendicular to movement of the web) so that the web moves evenly over the roller, and maintains a straight path between rollers of the system. The axis of the camber roller is generally perpendicular to the machine direction (oriented in the cross-machine direction), but is movably mounted so that the roller 68 may be moved slightly away from perpendicular to the machine direction. In this way, the web moving over the roller can be adjusted from side-to-side on the roller to center the web. Due in part to the presence of wrinkles and the lateral activation operation imparted on the web, the web moving from the activation station 54 may be uncentered and/or may have uneven edges (the outer edges of the web are not equidistant from the outer edges of the camber roller, for example, due to the presence of wrinkles).

Returning to the discussion of the camber roller assembly, each bracket is coupled to a servo motor assembly 88. The servo motor 82 is operably coupled with a pair of roller guides 90. Each roller guide includes a guide rod 92 or other member defining an axis angularly offset from the cross-machine direction. In the particular embodiment illustrated herein, the roller guides are each arranged with a forward angle such that each respective guide rod (92A, 92B) has an outer end in a rearward orientation and a forward end in a forward orientation toward the center of the roller 68. Hence, the rods (92A, 92B) converge toward each other forward the center of the roller. For purposes of this discussion, the front of the machine is the side shown in FIGS. 4-7. Further, the guide blocks (94A, 94B) are movably supported on the guide rods (92A, 92B). The servo motor is coupled to the left guide block to cause the guide block to move along the guide rod 94A. In this way, as shown by the arrows of FIG. 6, if the left guide block 94A, for example, moves slightly leftward and the right guide block 94B is also moved leftward along respective guide rods, then the camber roller is adjusted such that its left side is moved rearward and its right side is moved forward. In contrast, if the left guide block moves slightly right and the right guide block correspondingly moves slightly right, then the camber roller is adjusted such that the left side moves slightly forward and its right side moves slightly rearward. By adjusting the camber roller in this way, the edges of the web 80 and the web 20 itself may be substantially centered on the camber roller. Referring to the first example and the associated arrows, if the left and right blocks (94A, 94B) are moved leftward causing the camber roller 68 to be angularly positioned with respect to the web such that the left side of the camber roller (68A) is slightly rearward and the right side of the camber roller (68B) is slightly forward, the web 20 will track laterally across the roller from right to left. As the web moves through the edge sensors 78, the left and right edges 80 of the web are detected and corresponding feedback signals are provided to the servo 82 to adjust the camber roller to keep the web centered on the roller.

Various degrees of folding and web off-center variance may be experienced in any particular implementation. It is possible, for example, for there to be between 10-15 millimeters of variance, and hence the camber roller to adjust the web to account for this degree of variance, which may not result in the web being precisely centered. The web will experience some degree of off-center variance even after centering due to variability in folds and the degree to which any particular centering implementation can account for such variance. Further, it is possible to deploy others mechanisms to center the web, such as an offset pivot guide, a pivot table, etc., some of which are supplied by FIFE Corporation as referenced herein. The term “centering” or the like as used herein indicates that the web is adjusted or otherwise positioned so that the web enters the spreader assembly with the web edges relatively evenly fed in the assembly to substantially uniformly spread the web to remove folds. In a particular implementation where the machine center line corresponds with the center line of the spreader roller, as discussed above, and the spreader plates are symmetrically positioned relative to the machine center line, then “centering” indicates that the web is adjusted so that the web edges are substantially equidistant from the machine center line.

FIGS. 8A-8C illustrate representative examples of the web 20 as it enters the camber roller with a wrinkle 66 and with misaligned edges (80A, 80B) (FIG. 8A), as the folded web exits the camber roller and enters the power spreader with the edges centered (FIG. 8B), and finally as the unwrinkled and centered web exits the spreader. FIGS. 8A-8C are discussed in conjunction with the method set out in the flowchart of FIG. 9. Referring first to FIG. 8A, it can be seen that when the web 20 enters the camber roller assembly, the web may include a fold 66 or a wrinkle and the web may not be centered. In the example of FIG. 8A, there is a fold along the left side of the web. Additionally, the left edge (80A) of the web is positioned to the right of a left web edge target location 96A by amount X₁. The right side of the web does not have a wrinkle or fold and the right edge 80B of the web is outside (to the right) of a right web edge target location 96B by amount X₂. The left web edge and right web edge target locations correspond to the full width of the web centered on the roller. Thus, processing of the web by centering and spreader assemblies discussed herein begin with a folded web (operation 900, FIG. 9). The target locations are equidistant from the respective outer edge of the roller and the machine center line M, in one example.

After the web has moved through the camber roller assembly, as shown in FIG. 8B, the fold 66 on the left side of the web is still present, but the left and right edges (80A, 80B) of the web have been substantially centered (i.e., the left and right edges of the web are substantially equidistant by amount X₃ from the left and right target locations (96A, 96B) (operation 910). Due to the presence of the fold, the web center line W is not aligned with the machine center line M, even though the folded web and the left and right edges of the web have been centered. As discussed above, some form of sensor arrangement, whether edge sensors or otherwise, detect the position of the web relative to the machine center line and provide the appropriate signals to the centering mechanism (operation 920). The sensors may be positioned to detect the web edges or other aspect of the web before or after the centering mechanism. The sensors also provide a signal or signals to the spreader mechanism to adjust the degree of spreading commensurate with the relative position of the edges (80A, 80B) to the target location (96A, 96B). Hence, the greater X₃, the greater degree of spreading and the lesser X₃, the lesser degree of spreading.

As will be discussed in further detail below with respect to the spreader mechanism and referring now to FIG. 8C, when the web 20 is subsequently processed in the spreader assembly, the fold is removed from the left side of the web and the web is spread such that left and right outer edges (80A, 80B) of the web are aligned with target locations (96A, 96B) and thus the center line W of the web is aligned with the machine center line M (operation 930).

Referring now in more detail to the power spreader assembly 70 illustrated in FIGS. 4-7 and 10-11, the power spreader assembly includes an outer roller sleeve 98 mounted on a roller body 100 defining a spreader roller 102. The roller sleeve supports the web as the web moves over the power spreader assembly. The power spreader assembly includes four opposing spreader plates (104A, 104B, 104C, 104D). The spreader plates are positioned as two pairs (104A, 104C and 104B, 104D) spaced 180 degrees apart on the outer surface of the sleeve 98. Each pair of spreader plates is arranged to synchronously oscillate along the outer surface of the roller sleeve from an inner location when a pair of plates first contacts the web outwardly along the sleeve to spread the web and then back to the inner location as the spreader roller rotates to position the pair of plates 104 to again engage the web. When one pair of plates is at an outer location and beginning to reset to an inner position, the other pair is at an inner location and moving relatively outwardly to spread the web.

As shown in FIG. 10 and others, each spreader plate is a substantially rectangular member defining an arcuate contour with the same diameter as the outer circumference area of the roller sleeve. Accordingly, each spreader plate 104 is arranged flatly against the outer surface of the roller sleeve 98.

The outward facing surface of each spreader plate 104 defines two different surface areas, an outer rough 106 or gripping surface that is arranged along the side of the spreader plate adjacent to the outer edges of the spreader roller and an inner smooth surface 108. As the spreader plates engage the web and move from an inner position outwardly (see arrows of FIG. 10), the outer gripping surfaces engage the outer edge 80 regions of the web and pulls each outer edge outwardly over the roller sleeve. The inner smooth area of the spreader plate allows the web material to move over the spreader plate without binding. In this way, the spreader plates spread the web outwardly toward each side of the roller (and target locations 96A, 96B) and also allow web wrinkles and folds 66 to be removed as the portion of the web engaging the smooth section of the spreader plate is able to slide over the plates. Additionally, as mentioned above, the roller sleeve 98 defines an inner recessed region 110 centrally located between the outer raised regions 112 of the sleeve that support the spreader plates. Thus, the inner area has a lesser circumference than the adjacent outer area. With this configuration, the area of the web positioned over the recessed region 110 of the sleeve is able to be stretched and moved without binding on the roller sleeve surface. The web can move over the roller surface without the recess; however, the recess helps to prevent the web from snagging or otherwise engaging some surface and thereby preventing some of the wrinkle from unwrinkling.

Referring now primarily to FIGS. 4, 6 and 11 (illustrating exploded views of the power spreader assembly) the spreader plates (104A-104D) are each mounted to respective plate coupling members (114A-114D). The plate coupling members are each coupled to a spreader mechanism 116 and are each provided in a channel 118 in the roller sleeve. For each pair of plates and associated plate coupling members there is an associated pair of aligned channels 118 in the cross-machine direction. The channels run from an inner area outwardly toward the outer edge of the sleeve. Accordingly, the coupling members 114 moving in the respective channels are able to move the spreader plates 104 inwardly and outwardly by way of the spreader mechanism discussed below.

Referring primarily to FIG. 11, the spreader mechanism 116 supports each spreader plate (104A-104D) such that when one pair of spreader plates is moving inwardly toward each other (e.g., plates 104B and 104D), the opposing pair of spreader plates (e.g., plates 104A and 104C) located 180 degrees from the first pair of spreader plates, are moved outwardly away from each other toward the outer edges of the roller sleeve. This allows a pair of spreader plates to engage and begin spreading the web every half rotation of the spreader roller. It is possible to only include one pair of spreader plates, but such a single pair would only engage the web once per rotation of the roller. Other plate arrangements and mechanisms are also possible.

The spreader mechanism includes the first plate coupling member 114A coupled to the opposing second coupling member 114B by way of a cross-coupling member 118. Similarly, the spreader mechanism includes the third plate coupling member 114C coupled to the respective opposing fourth plate coupling member 114D by way of a second cross-coupling member 120. Accordingly, the first plate coupling member 114A on one side of the roller sleeve is operably connected to the second coupling member 114B on the opposing side of the sleeve. Similarly, the third coupling member 114C is connected to the respective fourth coupling member 114D on the opposite side of the sleeve. The second plate coupling member 114B is clamped to a first piston rod 122 and the third plate coupling member 114C is clamped to a second piston rod 124. The first piston rod is configured to move freely through a sleeve 126 in the fourth plate coupling member 114D while the second piston rod is configured to move freely in a sleeve 128 in the first plate coupling member 114A. Thus, when the first piston rod 120 moves along its axis, it causes the second plate coupling member 114B and the first coupling member 114A to move in the same direction. Similarly, when the second piston rod 124 moves along its axis, it causes the third and fourth coupling members (114C and 114D) to move in the same direction.

One end of each respective piston rod are coupled to a wobble plate 130, while the right side of each rod is movably supported in a respective sleeve 132. The wobble plate is configured to teeter about a point between the piston rods such that the piston rods move in opposing directions. For example, if the first piston rod moves in direction D₁, the second piston rod will move in direction D₂. Note, FIG. 11 illustrates the opposite side of the spreader assembly from FIG. 4, among others. Thus, the D₁ and D₂ directional arrows are illustrated appropriately.

Discussing now the coordinated movement of the spreader assembly, if the first piston rod 122 moves in Direction D₁, then the second plate coupling member 114B will similarly move in direction D₁ along with attached spreader plate 104B, which moves from an outer position along the roller sleeve to an inner position along the roller sleeve.

As the first plate coupling member 114A is operably connected with the second plate coupling member 114B by way of the cross-coupling member 118, when the first piston rod 122 moves in direction D₁, the first plate coupling member 114A also moves in direction D₁ from an inner position along the roller sleeve to an outer position along the roller sleeve (see also FIG. 10), opposite the relative direction of the second plate coupling member (moves from an outer position to an inner position). As the first piston rod 122 is moving in direction D₁, the second piston rod 124 is moving oppositely in direction D₂. Accordingly, the third plate coupling member 114C moves outwardly from the inner position along the sleeve to an outer position along the sleeve. As the fourth plate coupling member 114D and associated spreader plate 104D are coupled to the third plate coupling member 114C by way of the cross-coupling member 120, the fourth plate coupling member 114D moves inwardly from an outer position along the roller sleeve to an inner position along the roller sleeve as the second piston rod moves along D₂. In this way, the second and fourth plate coupling members (114B, 114D) and the respective spreader plates (104A, 104C), move inwardly from outer positions on the roller sleeve to inner positions on the roller sleeve, and in synchronization the opposing first and third plate coupling members (114A, 114C) and respective spreader plates (104A, 104C) move in a coordinated fashion from an inner position on the roller sleeve to an outer position on the roller sleeve. When the first piston rod moves along D₂ and the second piston rod moves along D₁, the opposing movements are imparted on the spreader plates (i.e., the first and third plate coupling members move from outward positions to inward positions and the second and fourth plate coupling members move from inward positions to outward positions).

An actuator 134 is coupled to the wobble plate 130 at member 136. The actuator controls the degree of actuation (or teetering) of the wobble plate and hence the degree of stroke of the piston rods (122, 124). The actuator may be configured to receive a signal from the edge sensors 78, and use the signal to control the degree of actuation of the wobble plate. Hence, if the edge sensor detects a relatively wider web (indicative of a lesser degree of folding) compared to a relatively narrower web (indicative of a greater degree of folding), then the actuator is configured to provide a lesser or greater degree of stroke on the piston rods, respectively. In this way, the plates will impart a greater or lesser degree of relative movement to spread the web a greater or lesser degree. So, for example, if the edge sensors detect a relatively wider web indicative of a relatively lesser degree of folding or wrinkling, then the actuator will impart a relatively lesser degree of stroke and consequently lesser degree of relative movement of the spreader plates. This allows the spreader plates to spread the web sufficiently to remove the fold or wrinkle, but not overspread the web, which may deform some of the elastic components, which may then not have sufficient time to contract to normal size in the immediately following side cutting stage 72A (which cuts the leg notches in the example of a diaper) and otherwise damage the web in any particular configuration.

Although various representative embodiments of this invention have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of the inventive subject matter set forth in the specification and claims. All directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the embodiments of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention unless specifically set forth in the claims. Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other.

In some instances, components are described with reference to “ends” having a particular characteristic and/or being connected to another part. However, those skilled in the art will recognize that the present invention is not limited to components which terminate immediately beyond their points of connection with other parts. Thus, the term “end” should be interpreted broadly, in a manner that includes areas adjacent, rearward, forward of, or otherwise near the terminus of a particular element, link, component, member or the like. In methodologies directly or indirectly set forth herein, various steps and operations are described in one possible order of operation, but those skilled in the art will recognize that steps and operations may be rearranged, replaced, or eliminated without necessarily departing from the spirit and scope of the present invention. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting.

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 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 can 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.

Claims

1. A method of processing a web comprising:

in a web processing system defining a machine center line and a cross-machine direction substantially perpendicular to the machine center line, receiving a moving web defining a first side edge and a second side edge, the web further having one or more wrinkles;

adjusting the web in the cross-machine direction; and

laterally spreading the web to substantially remove the one or more wrinkles.

2. The method of claim 1 wherein the adjusting operation further comprises:

detecting a difference between a first distance and a second distance, the first distance being between the first side edge and the machine center line and the second distance being between the second side edge and the machine center line.

3. The method of claim 2 wherein the first distance is between the first side edge and a first target location a set distance from the machine center line and the second distance is between the second side edge and a second target location the set distance from the machine center line.

4. The method of claim 2 wherein the operation of detecting occurs between the adjusting and laterally spreading operations.

5. The method of claim 2 wherein the adjusting operation further comprises:

adjusting the web so that the first distance and the second distance are substantially equal.

6. The method of claim 1 further comprising the operations of:

receiving, in association with the adjusting operation, at least one control signal indicative of the difference;

adjusting the web in the cross-machine direction as a function of the at least one signal.

7. The method of claim 1 further comprising:

prior to the adjusting operation, activating at least a portion of the moving web in the cross-machine direction, the operation of activating forming at least some of the one or more wrinkles.

8. The method of claim 1 wherein the operation of laterally spreading includes:

engaging the moving web adjacent the first side edge;

engaging the moving web adjacent the second side edge; and

allowing the moving web to freely move over an area between the first side edge and the second side edge to spread the web and substantially remove the one or more wrinkles.

9. The method of claim 1 wherein the moving web comprises a plurality of diapers and the method further comprising:

following the laterally spreading operation, cutting each of the plurality of diapers from the moving web.

10. The method of claim 1 further comprising the operations of:

detecting an aspect of the web indicative of a distance between the first side edge and the second side edge; and

controlling the laterally spreading of the web to substantially remove the one or more wrinkles as a function of the aspect of the web indicative of the distance between the first side edge and the second side edge.

11. A web processing system defining a machine center line and a cross-machine direction configured to process a moving web defining a first side edge and a second side edge comprising:

a web centering assembly comprising a centering mechanism in communication with at least one sensor configured to detect the relationship between the moving web and the machine center line, the centering mechanism configured to receive at least one signal indicative of the relationship between the moving web and the machine center line and adjust the moving web in the cross-machine direction; and

a web spreading assembly including a spreader roller defining a first circumference and a second circumference substantially equal to the first circumference, and a third circumference less than the first and second circumference and positioned between the first and second circumferences, the spreader roller moveably supporting a first plate and a second plate on at least a portion of the first and second circumference, respectively, the first and second plate arranged to engage the web received from the web centering assembly in a region of the first and second edge side edges respectively, and move substantially in the cross-machine direction to spread the web.

12. The web processing system of claim 11 wherein:

the first plate defines an outer area with a surface configured to engage the web in the region of the first side edge; and

the second plate defines a second outer area with a second surface configured to engage the web in the region of the second side edge.

13. The web processing system of claim 12 wherein:

the first plate defines an inner area adjacent the outer area, the inner area having a low coefficient of friction surface configured to allow the web to freely slide of over the inner area; and

the second plate defines a second inner area adjacent the second outer area, the second inner area having a low coefficient of friction surface configured to allow the web to freely slide over the inner area.

14. The web processing system of claim 13 wherein:

the first plate defines an arc with a diameter substantially the same as a diameter of the spreader roller at the first circumference; and

the second plate defines an arc with a diameter substantially the same as a diameter of the spreader roller at the second circumference.

15. The web processing system of claim 11 wherein the moving web includes a plurality of diapers, the system further comprising:

a web activation station configured to intermittently activate the diaper web in the cross-machine direction and subsequently provide the moving web to the web centering assembly and

a web cutting station configured to receive the moving web from the web spreading assembly and cut the individual diapers from the moving web.

16. The system of claim 11 wherein the web centering assembly comprises means for centering the web in communication with means for detecting an edge of the web.

17. The system of claim 11 wherein the web spreading assembly comprises means for spreading the web.

18. The system of claim 11 wherein the web spreading assembly is further configured to receive the at least one signal indicative of the relationship between the moving web and the machine centerline, the web spreading assembly further configured to control an amount of movement of the first plate and second plate substantially in the cross-machine direction to spread the web as a function of the at least one signal.

19. A web spreading assembly comprising:

a spreader roller configured to receive a web, the spreader roller having an outer substantially circumferential surface defining a first circumference, a second circumference substantially equal to the first circumference, and a third circumference less than the first and second circumference and positioned between the first and second circumferences;

the spreader roller moveably supporting at least a first plate and second plate on at least a portion of the first and second circumference, respectively, the first and second plates arranged to engage the web and move substantially in the cross-machine direction to spread the web;

the spreader roller including a spreader mechanism coupled with the first plate and the second plate and configured to move the first and second plates substantially in the cross-machine direction, the spreader mechanism receiving at least one control signal indicative of a width of the web, the spreader mechanism configured to control an amount of movement of the first plate and the second plate in the cross-machine direction as a function of the at least one control signal;

the first plate defines an outer area with a surface configured to engage the web in the region of the first side edge, the first plate further defines an inner area adjacent the outer area, the inner area having a low coefficient of friction surface configured to allow the web to freely slide of over the inner area; and

the second plate defines a second outer area with a second surface configured to engage the web in the region of the second side edge, the second plate further defines a second inner area adjacent the second outer area, the second inner area having a low coefficient of friction surface configured to allow the web to freely slide over the inner area.

20. The web spreading assembly of claim 19 wherein the spreader mechanism is supported within the spreader roller, the spreader mechanism including a first member at least partially extending through a first lateral channel in the spreader roller and coupled with the first plate, the spreader mechanism including a second member at least partially extending through a second later channel in the spreader roller and coupled with the second plate, the first member operably coupled with a first piston configured to move in the cross-machine direction, the second member operably coupled with a second piston arranged to move in the cross-machine direction opposite the movement of the first piston whereby the first and second plates engage the web in a first relative position and move laterally and away to a second relative position to spread the web.