VACUUM EAR-FOLDING PROCESS AND APPARATUS

Abstract: A process and apparatus (20) for folding a moving web (26) includes a blade member (38) which can operatively engage and fold the web (26), and a guide member (40) joined to the blade member (38). A holder mechanism (56) is operatively connected with the guide member (40) to control a portion (28) of the web (26) during the folding of the moving web. In particular aspects, the holder mechanism can include a vacuum device (57, 87) which tensions an appointed folded portion (28, 30) of the web.

Description: VACUUM EAR-FOLDING PROCESS AND APPARATUS Field of the Invention The present invention relates to a process and apparatus for folding a moving web More particularly, the present invention provides a process and apparatus which can more consistently and more accurately fold a selected portion of a moving web Background of the Invention Conventional folding board and guide mechanisms have been employed to fold an interconnected web of disposable diapers The web has typically been folded along its length from a substantially flat condition to produce a C-shaped, transverse cross-section Conventional devices have also been employed for perforating, Z-foldmg, and further processing long tissue webs to form stacks of Z-folded facial tissues or the like In one embodiment, two webs have been perforated and superimposed at the nip of counter rotating rolls so the perforations of one web are staggered between the perforations of the other web The webs have been Z-folded by vacuum adhering portions of the superimposed webs alternately to the portion of each roll below the nip, and drawing the adhered portions back and forth out of the mutual tangent plane forming the nip to start Z-folds Folding devices have incorporated a mechanism where by individual discrete sheets are elevated and picked up by a vacuum operated pickup shoe one-at-a-time to be deposited upon tape conveyors for transmission to a sheet folding section Devices have also been employed for folding precut sheet material such as disposable diaper blanks as they move in spaced-apart relation along the conveyor path Other conventional devices have employed a vacuum to hold a discrete sheet of material onto a folding board Still other devices have employed a vacuum spreader box to straighten a flat work before entering an ironer Conventional systems have also positioned a sub-assembly with a pre-pressed pleat on a vacuum device having a conforming pleat groove Other techniques have employed a vacuum device for flattening a sheet work piece and for unrolling or unbending a bent-over or rolled-up edge of a work piece without marring or damaging the work piece Another system has employed a fluid-operated stabilizing apparatus which receives an article having loose, wrinkled overlapping surfaces and by use of fluid flow control devices directs flows of fluid to the overlapping surfaces to fluidly shake the surfaces to smooth out wrinkles and any folded portions thereof The system aligns and holds the surfaces for subsequent treatment, such as bonding together A further system has employed at least one inner nozzle which directs a jet of air at a suspended web material to avoid creasing the material as it is laid Still another system has employed a vacuum for transferring a work piece from a first conveyor to a second conveyor Conventional systems have also employed a vacuum device to help fix a position of a strip during a taffling operation where the strip is delivered in a zig-zag pattern as a flat spiral with a pitch that preferably corresponds to the width of the strip Conventional techniques, such as those described above, have not adequately folded moving webs in high speed operations The conventional techniques have, for example, generated extraneous folds at undesired locations or have generated incomplete folds The conventional techniques have also produced uneven folding which have deviated away from the desired folding lines For example, where the fold lines were intended to be parallel to a movement direction of the web, the actual fold lines have been skewed and non-parallel to the movement direction Where the folded web was intended to be cut in a transverse direction that is perpendicular to the web movement direction, the cut line has had an uneven, jagged appearance, particularly when the web was unfolded As a result, there has been a continued need for improved folding devices and improved folding processes Brief Description of the Invention In an apparatus aspect of the invention, an apparatus for folding a moving web includes a blade member which can operatively engage and fold the web, and a guide member joined to the blade member A holder mechanism is connected to operatively cooperate with the guide member to control a portion of the web In a method aspect, a process for folding a moving web includes an engaging and folding of at least a first portion of the web with a first blade member, and a directing of the first portion of the web with a first guide member. The first portion of the web is controlled with a first holder mechanism which operatively cooperates with the first guide member. In particular configurations, the holder mechanism can include a vacuum device that operatively tensions a portion of the web appointed for folding. In other configurations, the invention can be configured to provide a desired, sequential folding of laterally opposed side portions of the moving web. The method and apparatus of the present invention can more effectively and more consistently generate a folding of the moving web along a fold line that extends parallel to a machine-direction of the method and apparatus. The technique of the invention can advantageously avoid the generation of extraneous folds at undesired locations, can produce a more even folding along the desired fold lines, and can reduce the occurrence of incomplete folds. In its various aspects, the technique of the invention can reduce a sticking of the moving web during the folding process. Where the moving web is separated into individual articles, the technique of the invention can help produce a more consistent and straighter separation line along a cross-direction of the process and apparatus. Where the method and apparatus of the invention are employed to fold a plurality of two or more appointed portions of the moving web, the various configurations of the invention can advantageously be constructed and arranged to generate a more reliable, sequential folding of the different portions of the moving web. Brief Description of the Drawings The present invention will be more fully understood and further advantages will become apparent when reference is made to the following detailed description of the invention and the drawings, in which: Fig. 1 representatively shows a schematic side view of a folding system which incorporates the present invention; Fig. 2 representatively shows a schematic, partially cross-sectioned, end view of the folding system of the invention illustrated in Fig. 1 , with the web shown advancing out of the drawing; Fig. 3 representatively shows a schematic, top view of a composite web that can be folded with the present invention; Fig. 3A representatively shows a schematic, top view of a web that has been folded with the present invention; Fig. 4 representatively shows a schematic, top view of a prior art web that has been folded with extraneous, misaligned folds; Fig. 4A representatively shows an enlarged, schematic, a top view of a prior art article that has been produced from the web illustrated in Fig. 4; Fig. 5 representatively shows a top view of a first folding board that can be employed by the present invention; Fig. 5A representatively shows a side view of the first folding board illustrated in Fig. 5; Fig. 6 representatively shows a top view of a second folding board that can be employed by the present invention; Fig. 6A representatively shows a side view of the second folding board illustrated in Fig. 6; Fig. 7 representatively shows a top view of a folding system which incorporates first and second folding board mechanisms; Fig. 8 representatively shows a top view of a first folding board having a corresponding fold guide; Fig. 8A representatively shows a side view of the first folding board illustrated in Fig. 8; Fig. 8B representatively shows an end view of the first folding board illustrated in Fig. 8; Fig. 9 representatively shows a top view of a second folding board having a corresponding fold guide; Fig. 9A representatively shows a side view of the second folding board illustrated in Fig. 9; Fig. 9B representatively shows an end view of the second folding board illustrated in Fig. 9; and Fig. 10 representatively shows a top view of a folding system which incorporates first and second folding boards, with each folding board having an associated, corresponding fold guides. Detailed Description of the Invention It should be noted that, when employed in the present disclosure, the terms "comprisesM "comprising" and other derivatives from the root term "comprise" are intended to be open- ended terms that specify the presence of any stated features, elements, integers, steps, or components, and are not intended to preclude the presence or addition of one or more other features, elements, integers, steps, components, or groups thereof. With reference to Figs. 1 , 5 and 5A, a distinctive method and apparatus 20 for folding a moving web 26 can include a first blade member 38, and a first guide member 40 joined to the first blade member 38. The first blade member can operatively engage and fold the web 26. Additionally, the first blade member and the first guide member can comprise the components of a first folding board 36. A first holder mechanism 56 is directly or indirectly connected to operatively cooperate with the first guide member 40 to control a selected portion of the web 26. In particular aspects, the first holder mechanism 56 can advantageously tension or otherwise control the selected portion of the web 26 during the folding of the web. In other aspects, the web may include an interconnected plurality of selected web segments 100, and the method and apparatus can include a web divider 64 which can operatively separate the web into individual articles 120. With reference to Figs. 4 and 4A, a further aspect of the invention can include a second blade member 68 which can operatively engage and fold a portion of the web 26, and a second guide member 70 which is joined to the second blade member 68. A second holder mechanism 86 is directly or indirectly connected to operatively cooperate with the second guide member 70 to control a selected portion of the web 26. The second blade member and the second guide member can comprise the components of a second folding board 66, and the second holder mechanism 86 can advantageously tension or otherwise control the selected portion of the web 26 during the desired folding of the web. The process and apparatus of the invention have an appointed, longitudinally extending, machine-direction 22, and a transverse, laterally extending, cross-direction 24, as representatively shown in Figs. 1 and 2. For the purposes of the present disclosure, the machine-direction 22 is the direction along which a particular component or material is transported length-wise along and through a particular, local position of the apparatus and method. The cross-direction 24 lies generally within the plane of the material being transported through the process and is aligned perpendicular to the local machine- direction 22. Accordingly, in the view of the arrangement representatively shown in Fig. 1 , the cross-direction 24 extends perpendicular to the plane of the sheet of the drawing. The shown configurations of the technique of the invention can fold or otherwise process a substantially continuous web 26 which extends length-wise along the appointed machine-direction. Optionally, the technique may be configured to continually process a discontinuous web, that is discontinuously or intermittently formed along the machine- direction. The web 26 may be a single layer of material, or may be a composite web composed of a plurality of components. Additionally, one or more of the components may be discontinuously or intermittently distributed along the machine-direction. The web may, for example, be composed of one or more component materials that make the web absorbent to liquids, such as water, menses and/or urine. With reference to Figs. 3 and 3A, for example, the moving web 26 may include a liquid-permeable topsheet layer 122, a backsheet layer 124, and an absorbent body structure 126 composed of one or more absorbent components that are sandwiched and held between the topsheet and backsheet layers. The resulting, composite web can further include conventional fastener components, leg elastics, waist elastics, inner containment flaps, and other components employed with conventional absorbent articles. The web 26 can include a first side portion 28, a laterally opposed second side portion 30, and a web medial portion 32 which is interposed between the web side portions. In desired arrangements, for example, the moving web 26 may represent an interconnected series of article segments 100 which can be separated to form individual articles 120. In particular aspects, the individual articles may be absorbent articles, such as disposable infant diapers, children's training pants, adult incontinence products, feminine care products, disposable garments, absorbent wipes, or the like. The moving web 26 can include at least one appointed folding line 96. In the representatively shown configuration, the technique of the invention is configured to provide a pair of laterally opposed fold lines 96 and 96a. As representatively shown, the fold lines are substantially parallel to each other and extend along the machine- direction 22. The medial portion 32 of the moving web 26 is a portion of the moving web which is relatively inboard from the appointed folding lines. In the shown configuration, the first side portion 28 is the web portion which is relatively outboard from its corresponding folding line 96. Similarly, the second side portion 30 is the web portion that is relatively outboard from its corresponding folding line 96a. For purposes of the present disclosure, the term, inboard, is along the cross-direction 24 of the method and apparatus, and designates a position which is relatively closer to the longitudinally extending center- line 62 of the web. The term, outboard, is also along the cross-direction 24 of the method and apparatus and denotes a position which is relatively farther from the longitudinally extending center-line 62 of the web. The side portions 28 and/or 30 of the moving web 26 can be substantially uniform in shape, or can be non-uniform in shape. For example, a non-uniform side portion can include a regularly or irregularly undulating contour which provides the web 26 with a variable cross-directional width. At least one of the web side portions can be provided with an alternating series of intermittently occurring ear sections 90 and inset sections 92. Each ear section 90 can project laterally beyond a terminal side edge 94 of an immediately adjacent inset section 92 of the web. Thus, at each inset section 92, the side portion of the web 26 can have a contour which is generally concave in the laterally, outboard direction, and at each ear section, the side portion of the web can have a corresponding contour which is generally convex in the laterally, outboard direction. The folding of an appointed web side portion operatively folds each of the corresponding ear sections 90 along its corresponding fold line 96 that extends generally along the movement, machine-direction of the web 26. Desirably, the corresponding fold lines can extend substantially parallel with the machine-direction of the moving web. In particular aspects, the folding of the web 26 can produce a fold line 96 which is positioned laterally outboard from an innermost portion of the terminal side edge 94 of the inset section 92 of the web 26. In further aspects, the folding of the web can position the fold line 96 laterally inboard from the innermost portion of the terminal side edge 94 of the inset section 92 of the moving web 26. In desired aspects, the fold line 96 can be positioned to approximately intersect the innermost portion of the terminal side edge 94. The fold line 96 can alternatively be positioned laterally inboard from the innermost portion of the terminal side edge 94 of the inset section 92 of the moving web by a distance which is at least about 1 cm. In other aspects, the inboard distance can be not more than about 4 cm. Conventional folding devices, however, have not adequately folded the moving web, particularly where the web has contoured side portions, and where the desired fold lines 96 are positioned in relatively close proximity to the innermost portion of the terminal side edge 94 of the web inset sections 92. Difficulties have also increased where the desired fold lines 96 are positioned relatively more outboard and farther from the lengthwise centerline 62 of the web, or when the innermost portion of the side edge 94 is positioned closer to the web centerline 62. The conventional folding devices have produced fold lines 96 that have not been adequately aligned sufficiently parallel to the machine- direction 22 of the method and apparatus. Instead, the fold lines have been nonparallel and skewed at an angle to the machine-direction. Additionally, undesired extraneous folds 97 have been produced in the web. As a result, when the folded web is divided along straight, cross-directional division lines 98 to form individual articles 120, the combination of the straight division line and the skewed and/or extraneous folding of the web can generate a malformed article, as representatively shown in Figs. 4 and 4A. In particular, when the article is opened and unfolded, a terminal edge of the unfolded article is uneven, jagged and unsightly. The uneven edge can undesirably contribute to poor fit, poor appearance, excessive irritation and excessive leakage. With reference again to Figs. 1 and 2, a suitable transport mechanism is employed to move the web 26 through the method and apparatus of the invention. The transport mechanism can incorporate any conventional transporting device, such as a system of transport rollers, a conveyor belt system, a system of gas jets, an electro-magnetic suspension system, or the like, as well as combinations thereof. As representatively shown, the selected transport system can include an entry member or drum 34 which directs the moving web 26 to the location of a first folding board mechanism 36. The entry member may or may not be rotatable, but desirably includes the illustrated rotatable roller or drum 34. The entry member has an axial, length aligned along the local cross- direction 24, and the axial length of the entry member can desirably be not more than the appointed cross-directional width of the final, folded condition of the web 26. In the representatively shown configuration, the moving web 26 is operatively directed to the entry drum 34, and the drum is configured to contact and engage the medial portion 32 of the moving web. Additionally, the web 26 is arranged to move along a curved path that traverses circumferentially around a portion of the cylindrical outer surface of the entry drum. As the moving web is carried around the circumference of the entry drum, the web is typically under an applied tension, and the relatively unengaged side portions 28 and 30 of the web tend to curl or otherwise move around the side edges of the entry drum. Additional side plates may be operatively placed in proximity to each of the cross- directionally opposed, axial facing surfaces of the entry drum to assist in the desired curling movement of the web side portions. Each of the web side portions tends to move toward a z-direction that is perpendicular to both the local machine-direction 22 and the local cross-direction 24. Accordingly, when the portion of the web 26 that engaged by the entry drum is viewed with respect to a section along the cross-direction, the sectional view will show a generally U-shaped configuration. The moving web is thereby urged into a channel-like, trough arrangement with the web side portions 28 and/or 30 extending lengthwise along the machine-direction but turned around the axial ends of the entry drum toward the local z-direction to extend at an angle to the local cross-direction. The trough arrangement of the web is directed to at least the first folding board 36, and desirably is directed to a cooperating system which includes the folding boards 36 and 66. In particular aspects, the entry drum is configured and arranged to force and steer the medial portion 32 of the web 26 along a web path runs underneath the folding blade members of the selected system of folding boards. The chosen transporting system moves the web 26 along the appointed web path and through the selected system of folding boards. As representatively shown, the transporting system can include a moving, foraminous screen, endless conveyor belt 112 which is operatively driven and guided by a cooperating set of belt rollers 114. To help hold the web 26 on the screen conveyor belt, the transporting system can include a vacuum suction box 110 which is operatively connected to a conventional vacuum pumping mechanism. Accordingly, the suction box is configured and positioned to generate an appropriate pressure differential that operatively holds at least the medial portion 32 of the web against the transporting screen belt 112. The movement of the web 26 through an operative engagement with the first folding board 36 folds the selected first side portion 28 of the web, and the movement of the web 26 through an operative engagement with the second folding board 66 folds the selected second side portion 30 of the web. Upon leaving the location of the selected system of folding boards, the moving web can be divided into a plurality of individual articles. A suitable separating mechanism can, for example, include a conventional system composed of a rotary knife 64 and cooperating anvil roll 65. As representatively shown in Figs. 5 and 5A, the first folding board 36 includes a first blade member 38, and provides a first folding board entrance, folder edge 42. The first blade member 38 provides a base component of the folding board 36, and includes a first, entrance-side surface 44 and a second, opposed exit-side surface 46. In the illustrated configuration, the entrance-side surface 44 is a top-side surface of the blade member, and the exit-side surface 46 is a bottom-side surface of the blade member. The first guide member 40 is attached or otherwise operatively joined along the entrance edge portion 42 of the first blade member. In desired arrangements, the first guide member 40 extends along a substantial entirety of the entrance edge portion 42 of the first blade member 38. The first guide member 40 is configured to project away from the first surface 44 of the first blade member 38. In desired aspects, the first guide member 40 can be configured to project away from the first surface 44 of the first blade member 38 in a direction which is generally perpendicular to a plane of the first blade member 38. In other aspects, the first guide member can be configured to project away from the first, entrance-side surface of the first blade member in a non-perpendicular direction. The projecting direction can, for example, be at an angle which is within the range of about 90 - 110 degrees from a base plane generally defined by the first blade member 38. In particular configurations, a selected guide member can be selectively curved or otherwise contoured to provide a more consistent and accurate operation. In the representatively shown configuration, for example, the first guide member 40 can be inwardly bent and curved toward the longitudinally extending center line 62 of the moving web 26. Additionally, an entrance-end portion of the first guide member 40 can be outwardly curved away from the location of the web center line 62. In other aspects, an exit-end portion of a selected blade member can be selectively curved or otherwise contoured to provide a more efficient and more accurate folding of the moving web 26 along its appointed folding lines. For example, the first folding blade member 38 can be slightly bent and curved to be concave along its exit-side surface 46, and convex along its opposed, entrance-side surface 44. Suitable mounting components are desirably employed to secure the first folding board 36 to a conventional support system, such as a conventional mounting and support frame. In the representatively shown configuration, for example, mounting blocks 60 are operatively constructed and arranged to secure the first folding board. In the various configurations of the invention, the selected holder mechanism is configured to apply a tensioning force to its corresponding side portion of the moving web 26 during the desired folding of the web. The technique of the invention can advantageously control the folded portions of the web 26 by providing and applying a resilient, releasable tensioning of the folded portions of the web. The tensioning of the first portion 28 of the moving web 26, for example, can urge the web against the first entrance edge 42 of the first blade member 38. Additionally, the controlling of the first portion 28 of the web can orient the first portion of the web toward a position that is generally parallel to a surface defined and provided by the first guide member 40. For example, the holder mechanism 56 can exert a tensioning force which draws and tightens the appointed first side portion 28 of the moving web against the entrance edge portion 42 of the first blade member 38. In addition, the holder mechanism 56 can apply a tensioning force which draws the first side portion 28 against an inboard side surface 41 of the first guide member 40. As a result, the holder mechanism can operatively apply a resilient, releasable tensioning force to the first side portion 28 during the process of folding the first side portion along its appointed folding line 96 (e.g. Fig. 3). The applied force generates a reflex bend about the entrance edge portion 42 of the first blade member 38, and the reflexed bend is located generally inboard from its corresponding appointed fold line 96. The holder mechanism can thereby be configured to more consistently provide for a folding of the first side portion 28 of the moving web 26 along a fold line 96 that is substantially parallel with the movement, machine-direction of the moving web 26. In particular aspects, the holder mechanism can comprise a vacuum module. A first vacuum module 57 can include a cover wall member 50 which is operatively connected to the first guide member 40, and a shroud member 52 which is joined to the cover member 50. An outlet conduit 54 is joined to the module 57 and a suitable airflow driver produces an air stream which moves into the first vacuum module 57 and out from the outlet conduit 54. Additionally, the first vacuum module 57 can include a duct, side wall member 48 which is directly or indirectly joined to the first guide member 40. In the example of the representatively shown configuration, the first guide member 40 is operatively joined to an entrance region of the first side wall. Additionally, the first cover wall member 50 is operatively joined to a duct region of the first side wall member 48. In the various configurations of the invention, the outlet duct of each vacuum module can be of any suitable cross-sectional shape, such as round, oval, rectilinear, polygonal or the like, as well as combinations thereof. Additionally, each vacuum module can incorporate a plurality of more than one outlet duct. In the representatively shown arrangement, for example, the outlet conduit is substantially circular with a diameter of about 7.6 cm. It has been found that it is important to maintain a smooth transition between the guide member of each folding board and the corresponding duct, side wall of its cooperating vacuum module. Accordingly, with regard to the first folding board 36, the upper, entrance-side edge 49 of the side wall 48 slopes and tapers down to gradually transition into the entrance-side edge of its corresponding guide member 40. If the transition is too abrupt, the moving web may catch and snag during the folding operation, and disrupt the process. In addition, it is important to suitably configure the cover member of the vacuum module to avoid interfering with the movement and folding of the web. The cover member is spaced by a selected distance away from the blade member of its corresponding folding board, and the location and shape of the cover member is selected to accommodate the size and shape of the corresponding folded section of the web 26. Desirably, the spacing distance is kept small to increase the effectiveness and efficiency of the vacuum induced airflow that tensions and controls the web during the folding operation. In particular configurations, the airflow driver can be a conventional vacuum pump (not shown). Optionally, the airflow driver may be a rotary fan, an axial fan or the like, as well as combinations thereof. With reference to Fig. 1 , each vacuum module can further include a regulator mechanism 58 for controlling a holding force produced by the air stream in the vacuum module of the first folding board 36. In particular configurations, the first regulator mechanism can comprise at least one airflow damper located in the outlet conduit 54. The airflow damper can be rotated or otherwise adjusted to control the rate of airflow through the outlet conduit. Optionally, each vacuum module can employ other regulator devices, such as a ball valve, an iris device, or any other device that is capable of restricting the airflow, as well as combinations thereof. To generate the airflow through the vacuum module 57, the airflow driver can be configured to provide a desired vacuum pressure-differential for the vacuum module. In particular aspects the first vacuum module can provide a pressure-differential which may be up to about 6 centimeters of water, or more. In the shown arrangement, for example the pressure-differential for the first vacuum module 57 can be about -1.2 cm (about -0.5 inch) of water, where the "minus" (-) sign indicates a module air pressure that is below the ambient atmospheric pressure. Typically, the module air pressure is measured at the entry into the outlet conduit of the vacuum module. If the pressure-differential is too low, the vacuum module may provide an insufficient level of tensioning force on its corresponding web side portion 28. If the pressure-differential is too high, the first side portion 28 may be excessively drawn into the outlet conduit 54, and may cause plugging of the conduit and disruptions in the folding process. In another aspect, the method and apparatus of the invention can include a second folding board mechanism 66. With reference to Figs. 6 and 6A, the second folding board 66 can include a second blade member 68, and the second blade member can be laterally spaced from the first blade member 38 along the cross-direction 24 of the method and apparatus. The second blade member can operatively engage and fold a second portion 30 of the moving web 26. A second guide member 70 can be joined to the second blade member 68, and a second holder mechanism 86 can be joined to the second guide member 70. The second blade member 68 can have a construction and arrangement which is similar to that of the first blade member 38. Accordingly, the second blade member 68 provides a base component of the second folding board 66, and includes a first, entrance-side surface 74 and a second, opposed exit-side surface 76. In the illustrated configuration, the entrance-side surface 74 is a top-side surface of the blade member, and the exit-side surface 76 is a bottom-side surface of the blade member. The second guide member 70 is attached or otherwise operatively joined along an entrance edge portion 72 of the second blade member. In desired arrangements, the second guide member 40 extends along a substantial entirety of the entrance edge portion 72 of the second blade member 68. The second guide member 70 can have a construction and arrangement which is similar to that of the first guide member 40. Accordingly, the second guide member 40 is configured to project away from the entrance-side surface 74 of the second blade member 68. In desired aspects, the second guide member 70 can be configured to project away from the entrance-side surface 74 of the second blade member 68 in a direction which is generally perpendicular to a plane of the second blade member 68. In other aspects, the second guide member can be configured to project away from the entrance-side surface of the second blade member in a direction which is at an angle within the range of about 90 - 1 10 degrees from a base plane that is generally defined by the second blade member 68. The second guide member 70 can be selectively curved or otherwise contoured to provide a more consistent and accurate operation. In the representatively shown configuration, for example, an entrance-end portion of the second guide member 70 can be outwardly bent and curved away from the location of the web center line 62. Suitable mounting components are desirably employed to secure the second folding board 66 to a conventional support system, such as a conventional mounting and support frame. In the representatively shown configuration, for example, mounting blocks 60 are operatively constructed and arranged to secure the second folding board. Similar to the first holder mechanism 56, the second holder mechanism 86 is desirably configured to apply a tensioning force to its corresponding side portion 30 of the moving web 26 during the desired folding operation. The second holder mechanism can control its corresponding folded portion by providing and applying a resilient, releasable tensioning of its corresponding folded portion. The tensioning of the first portion 30 can urge the web against the second entrance edge 72 of the second blade member 68. Additionally, the controlling of the second portion 30 of the web can orient the second portion of the web toward a position that is generally parallel to a surface defined and provided by the second guide member 70. For example, the holder mechanism 86 can exert a tensioning force which draws and tightens the appointed second side portion 30 of the moving web against the entrance edge portion 72 of the second blade member 68. In addition, the holder mechanism 86 can apply a tensioning force which draws the second side portion 30 against an inboard side surface 71 of the second guide member 70. As a result, the holder mechanism 86 can operatively apply a resilient, releasable tensioning force to the second side portion 30 during the process of folding the second side portion along its appointed folding line 96a (e.g. Figs. 2 and 3). The applied force generates a reflex bend about the entrance edge portion 72 of the second blade member 68, and the reflexed bend is located generally inboard from its corresponding appointed fold line 96a. The holder mechanism 86 can thereby be configured to more consistently provide for a folding of the second side portion 30 along a fold line 96a that is substantially parallel with the movement, machine-direction of the moving web 26. The second holder mechanism 86 can have a configuration which is similar to that of the first holder mechanism 56. Accordingly, the second holder mechanism can include a second vacuum module 87 can include a cover wall member 80 which is operatively connected to the second guide member 70, and a shroud member 82 which is joined to the cover member 80. An outlet conduit 84 is joined to the module 87 and a suitable airflow driver produces an air stream which moves into the second vacuum module 87 and out from the outlet conduit 84. Additionally, the second vacuum module 87 can include a duct, side wall member 78 which is directly or indirectly joined to the second guide member 70. In the example of the representatively shown configuration, the second guide member 70 is operatively joined to an entrance region of the second side wall 78. Additionally, the second cover wall member 80 is operatively joined to a duct region of the second side wall member 78. As previously mentioned, it is important to maintain a smooth transition between the guide member of each folding board and the corresponding duct, side wall of its cooperating vacuum module. Accordingly, with regard to the second folding board 66, the upper, entrance-side edge 79 of the side wall 78 slopes and tapers down to gradually transition into the entrance-side edge of its corresponding guide member 70. If the transition is too abrupt, the moving web may catch and snag during the folding operation, and disrupt the process. Additionally, the cover member is spaced by a selected distance away from the blade member of its corresponding folding board, and the location and shape of the cover member is selected to accommodate the size and shape of the corresponding folded section of the web 26. Desirably, the spacing distance is kept small to increase the effectiveness and efficiency of the vacuum induced airflow that tensions and controls the web during the folding operation. The airflow driver employed for the second vacuum module 87 may be the same airflow driver employed for the first vacuum module 57. Optionally, the second vacuum module may incorporate a separate airflow driver, such as a second vacuum pump, or the like. The second vacuum module 87 can further include a second regulator mechanism 88 (e.g. Fig. 1 ) for controlling a holding force produced by the air stream in the second vacuum module. In particular configurations, the first regulator mechanism can comprise at least one airflow damper located in the outlet conduit 84. The airflow damper can be rotated or otherwise adjusted to control the rate of airflow through the outlet conduit. In further aspects, the second vacuum module 87 can be configured to provide an airflow which is substantially equal to the airflow provided by the first vacuum module 57. In other aspects, the second vacuum module 87 can be configured to provide an airflow which is different than the airflow provided by the first vacuum module 57. The difference in the applied vacuum and airflow can, for example, help to provide a desired sequential folding of the first and second portions of the web 26. Accordingly, the second vacuum module can be configured to provide a vacuum pressure-differential which may be up to about 6 centimeters of water, or more. In the shown arrangement, for example, the pressure-differential for the second vacuum module 87 can be about -4.5 cm (about -1.8 inch) of water, where the "minus" (-) sign indicates a module air pressure that is below the ambient atmospheric pressure. If the pressure-differential is too low, the vacuum module may provide an insufficient level of tensioning force on its corresponding web portion 30. If the pressure-differential is too high, the second web portion 30 may be excessively drawn into the outlet conduit 84, and may cause plugging of the conduit and disruptions in the folding process. With reference to Figs. 8 through 10, each folding board can include a fold guide 116 which operatively locates the position of the desired folded edge along the appointed fold lines 96 of the web 26. As representatively shown, each fold guide can be provided by a system which includes at least one, edge guide roller 118, and preferably includes a cooperating plurality of the edge guide rollers. Other alternative guiding devices can, for example, include plates, slider mechanisms, air jets or the like, as well as combinations thereof. As representatively shown, the position of each fold locator guide can be selectively moved along cross-direction of the folding system by employing a conventional adjustment mechanism 117. For example, adjustment screws, movable brackets, servos, or the like, as well as combinations thereof may be employed to modify the cross- directional positioning of the fold guides. With reference to Fig. 2, the first blade member 38 of the first folding board 36 can be positioned at a first blade height, and the second blade member 68 of the second folding board 66 can be positioned at a different, second blade height which is vertically offset from the first blade height. In the representatively shown configuration, the first blade height is relatively lower than the second blade height as a result, the first and second folding boards 36 and 66, respectively, can more effectively provide a sequential folding of their associated portions 28 and 30 of the moving web 26. The height positions of the first and second blade members can be adjusted during the operation of the process and apparatus to visually find the desired operational setting. In particular aspects, the height of the first blade member 38 can be at least a minimum of about 1.5 cm above the height of the conveyor or transport mechanism (e.g. the screen belt 1 12) employed to translate the moving web 26. The height of the first blade member can alternatively be at least about 1.7 cm to provide improved performance. In other aspects, the height of the first blade member can be not more than a maximum of about 4 cm, and the height of the first blade member can alternatively be not more than about 3 cm to provide improved effectiveness. In desired configurations, the height of the first blade member can be about 2 cm. If the height of the first blade member is too low, there can be an excessive pinching of the moving web 26, which can cause equipment jams and poor folding of the web. If the height of the first blade member is too large, there can be excessive slack in the folded portions of the web, which can cause undesired wrinkles and creases. While the invention may be configured with substantially zero height difference between the first and second blade members, the second blade member 68 can desirably be positioned at a selected height above the first blade member 38 to provide a operative blade height separation distance 59 (e.g. Fig. 2). In particular configurations, the height separation distance can be at least a minimum of about 0.1 cm, and can alternatively be at least about 0.6 cm, and optionally, can be at least about 1.2 to provide improved performance In other arrangements, the height separation distance can be not more than a maximum of about 3 cm to provide desired benefits If the blade height separation distance is too low, there can be an excessive pinching and an excessive drag applied to the second side portion of the moving web 26 Such conditions can cause a jamming or tearing of the web If the blade height separation distance is too large, there can be an incomplete folding of the web Additionally, there can be excessive slack in the folded portion of the web, which can cause undesired wrinkles and creases In another aspect, the entrance, folder edge portion 42 of the first blade member 38 can be positioned at a first location along the machine-direction 22 of the method and apparatus Additionally, the entrance, folder edge portion 72 of the second blade member 68 can be positioned at a different, second location along the machine- direction 22 With reference to Fig 7, the entrance edge portion 42 of the first blade member 38 can extend along a first engagement distance along the machine-direction 22 of the method and apparatus Additionally, the entrance edge portion 72 of the second blade member 68 can be configured to extend along a different, second engagement distance along the machine-direction With reference to Figs 1 , 2 and 7, the method and apparatus of the invention can provide a sequential inboard folding of the first and second side portions 28 and 30 of the moving web 26 In particular aspects of the invention, the folding of the first portion 28 of the moving web 26 can be completed prior to a completion of the folding of the second portion 30 of the moving web As representatively shown, the moving web 26 enters the system of folding boards 36 and 66, and approaches the folding boards generally towards the entrance-side surfaces 44 and 72 of the first and second blade members 38 and 68, respectively The entrance edge of the first folding blade member 38 is located upstream, relative to the entrance edge of the second folding blade member 68 Additionally the first folding blade member is located relatively lower and closer to the web 26, as compared to the second folding blade member Thusly arranged, the first folding board can provide an operative, initial folding of the web first side portion 28 prior to a relatively subsequent and sequential folding of the web second side portion 30 The relative positioning of the first and second blade members 38 and 68 can advantageously reduce the likelihood of undesired interference between the folding of the web first side portion 28 and the folding of the web second side portion 30. The folded web exits from the system of folding boards 36 and 66 by moving away from the exit-side surfaces 46 and 76 of the first blade member 38 and the second blade member 68, respectively. The web 26 can include an interconnected plurality of selected article lengths or segments 100 (e.g. Fig. 3 ), and the web can be divided into individual, discrete articles 120 (e.g. Fig. 4). Desirably, the dividing of the web occurs after the folding of the web 26 has been completed. Accordingly, an aspect of the invention can include a dividing mechanism which is configured to sever or otherwise separate the moving web 26 along a plurality of division lines 98 which extend substantially parallel to the cross- direction 24 of the method and apparatus. The divider mechanism can be any operative device, such as a die cutter, rotary die cutter, rotary knife, water cutter, laser cutter, electron beam cutter, energy beam cutter, or the like, as well as combinations thereof. In the shown configuration, the divider mechanism includes a rotary knife 64, and a cooperating, counter-rotating anvil roll 65. The divider mechanism can be operatively coordinated with the movement of the web employing conventional control systems that are well known in the art. Since the method and apparatus of the invention can more accurately and more consistently generate fold lines 96 and 96a that are substantially parallel to the machine-direction 22, the severing of the folded web 26 can provide a terminal, cross-directional edge of the open, unfolded article that is straight, evenly shaped and aesthetically pleasing. Having described the invention in rather full detail, it will be readily apparent that various changes and modifications can be made without departing from the spirit of the invention. All of such changes and modifications are contemplated as being within the scope of the invention as defined by the subjoined claims.

Claims: We claim: 1. An apparatus for folding a moving web, the apparatus comprising: a first blade member which can operatively engage and fold a first portion of said web; a first guide member joined to said first blade member; and a first holder mechanism joined to said first guide member to control said first portion of said web. 2. An apparatus as recited in claim 1 , wherein said first blade member has a first, entrance-side surface, a second, exit-side surface and an entrance edge portion; and said first guide member is joined along said entrance edge portion of the first blade member. 3. An apparatus as recited in claim 2, wherein said first guide member extends along a substantial entirety of said entrance edge portion of the first blade member. 4. An apparatus as recited in claim 1 , wherein said first guide member is configured to project away from said first surface of the first blade member. 5. An apparatus as recited in claim 1 , wherein said first holder mechanism is configured to apply a tensioning force to a side portion of said web during a folding of the web. 6. An apparatus as recited in claim 1 , wherein said first holder mechanism is configured to provide for a folding of a first side portion of said web along a first fold line that is substantially parallel with a movement direction of said moving web. 7. An apparatus as recited in claim 6, wherein said first holder mechanism comprises a first vacuum module, and said first vacuum module includes: a first cover member operatively connected to said guide member, a first shroud member joined to said cover member, a first outlet conduit joined to said module; and a first airflow driver which produces an air stream into said first module and out from said first outlet conduit. 8. An apparatus as recited in claim 7, wherein said first vacuum module further includes a first regulator mechanism for controlling a first holding force produced by said air stream in said first vacuum module. 9. An apparatus as recited in claim 8, wherein said first holder regulator mechanism includes at least one airflow damper located in said first outlet conduit. 10. An apparatus as recited in claim 7, wherein said first vacuum module further includes a first side wall; said first guide member is operatively joined to an entrance region of said first side wall; and said first cover member is operatively joined to a duct region of said first side wall. 1 1. An apparatus as recited in claim 1 , further including a dividing mechanism for separating said web into a plurality of individual articles. 12. An apparatus as recited in claim 1 , further comprising: a second blade member which is laterally spaced from said first blade member along a cross-direction of said apparatus, and is configured to operatively engage and fold a second portion of said web; a second guide member joined to said second blade member; and a second holder mechanism joined to said second guide member to control said second portion of said web. 13. An apparatus as recited in claim 12, wherein said first blade member is positioned at a first blade height, and said second blade member is positioned at a different, second blade height. 14. An apparatus as recited in claim 12, wherein an entrance edge of said first blade member is positioned at a first location along a machine-direction of said apparatus, and an entrance edge of said second blade member is positioned at a different, second location along said machine-direction. 15. An apparatus as recited in claim 12, wherein an entrance edge of said first blade member extends along a first engagement distance along a machine-direction of said apparatus, and an entrance edge of said second blade member extends along a different, second engagement distance along said machine-direction. 16. A process for folding a moving web, the process comprising: an engaging and folding of a first portion of said web with a first blade member; a directing of said first portion of said web with a first guide member; and a controlling of said first portion of said web with a first holder mechanism which operatively cooperates with said first guide member. 17. A process as recited in claim 16, wherein said directing of said first portion of said web directs said first portion with a first guide member which is joined to said first blade member. 18. A process as recited in claim 16, further comprising: an engaging and folding of a second portion said web with a second blade member; a directing of said second portion of said web with a second guide member; and a controlling of said second portion of said web with a second holder mechanism which operatively cooperates with said second guide member. 19. A process as recited in claim 18, wherein said directing of said second portion of said web directs said second portion with a second guide member which is joined to said second blade member. 20. A process as recited in claim 18, wherein said folding of said first portion of the web is completed prior to completing of said folding of said second portion of the web. 21. A process as recited in claim 16, wherein said controlling of said first portion of the web provides a resilient, releasable tensioning of said first portion of the web. 22. A process as recited in claim 16, wherein said tensioning of said first portion of the web urges said web against a first entrance edge of said first blade member. 23. A process as recited in claim 16, wherein said controlling of said portion of the web orients said portion of the web towards a position that is generally parallel to a surface defined by said guide member. 24. A process as recited in claim 16, wherein said controlling of said portion of the web includes a holding with a vacuum module. 25. A process as recited in claim 18 wherein said directing of said first portion of the web employs a first guide member which is joined to said first blade member; said controlling of said first portion of the web employs a first holder mechanism which is operatively joined with said first guide member; said directing of said second portion of the web employs a second guide member which is joined to said second blade member; and said controlling of said second portion of the web employs a second holder mechanism which is operatively joined said second guide member. 26. A process as recited in claim 25, wherein said controlling of said first portion of the web includes a holding with a first vacuum module; and said controlling of said second portion of the web includes a holding with a second vacuum module. 27. A process as recited in claim 26, further including a separating of said web into a plurality of individual articles.

Inventors: WEINIG LEE ARNOLD, WEINIG, LEE, ARNOLD
Applicants: KIMBERLY CLARK CO, KIMBERLY-CLARK WORLDWIDE, INC.
Application year: 2001
Main classification: B65H45
IPC codes: A61F13, B65H45