Apparatus and method for stretching an elastic segment and attaching it to a support web

Abstract

A method and apparatus for applying individual stretched film portions to a support web includes conveying a continuous elastic film in a longitudinal direction; operating a cutting unit to cut the continuous elastic film into a series of individual first film portions and individual second film portions; selectively adjusting a feed rate of the continuous elastic film upstream of the cutting unit; transferring the first and second film portions from a vacuum drum to a first pair of arms and a second pair of arms, respectively, of a stretching unit; stretching the first and second film portions in the transverse direction by laterally separating the first and second pairs of arms as the stretching unit rotates from a pick-up position to a transfer position; and transferring the stretched first and second film portions from the stretching unit to the support web.

Description

Technical Field

[0001] Embodiments of the present invention relate to a method and apparatus for stretching elastic segments and applying them to a support web in the manufacture of disposable absorbent articles such as diapers or incontinence garments. More specifically, embodiments of the present invention relate to such methods and apparatuses that enable changing the pitch or spacing between adjacent stretched elastic segments applied on a support web. By selectively controlling the feed rate when continuously feeding an elastic film in the longitudinal direction and cutting, stretching, and applying the elastic segments formed therefrom, the spacing between the elastic segments can be changed in a desired manner.

Background Art

[0002] Typically, disposable absorbent articles such as children's training pant type diapers or adult incontinence type diapers are formed from a combination of multiple web layers, an absorbent structure, and elastic elements. Thus, the article can include a thin flexible liquid-impermeable backing sheet over which a permeable nonwoven sheet is laid. An absorbent pad is disposed between the two sheets, and the sheets are adhered at their edges to form an integral article that prevents liquid body exudates from seeping out from the edges of the diaper. Elastic elements such as elastic waist elements and elastic leg cuffs are provided on the article to assist the article in better conforming to the wearer's body around the waist, back, and legs to prevent leakage along the interface of the nonwoven sheet in contact with the body.

[0003] In the manufacture of absorbent articles such as those described above, the elastic elements are often provided in the form of an arrangement of elastic strands that are sandwiched between a topsheet and a backsheet and captured within an adhesive that fixes them in place. To form a barrier along the sides of the absorbent core, the elastic strands can be applied along at least one of its front and rear sides and / or along both sides of the crotch of the article, along the waistline of the article.

[0004] Examples of articles that include such an arrangement of elastic strands are shown in FIGS. 1A and 1B. In FIG. 1A, the article 2 is provided in the form of a disposable incontinence absorbent article, and in FIG. 1B, the article 2 is provided in the form of a pant-type article, although it will be understood that other product configurations, such as baby diapers, may also include such elastic strands. As seen in each of the embodiments of FIGS. 1A and 1B, the article 2 includes a plurality of individual elastic strands 4 disposed along both sides of the crotch region that includes an absorbent core 6. The elastic strands 4 can be affixed in a stretched state and secured between the topsheet and the bottomsheet (collectively designated 8) of the article 2 by the use of an adhesive.

[0005] Generally, articles incorporating an arrangement of elastic strands for forming an elastic waistband and / or elastic leg cuffs are effective in preventing liquid body exudates from leaking out from the edges of the article. However, the disposable hygiene product industry is faced with a continuous evolution of a series of product designs and technological innovations in materials, and there may be cases where existing manufacturing processes and related system machinery cannot cope.

[0006] Therefore, it is desirable to provide an improved method and apparatus for forming an elastic material and attaching it to a disposable absorbent article. SUMMARY OF THE INVENTION

[0007] According to one aspect of the present invention, a method of attaching individual stretched film portions to a support web includes conveying a continuous elastic film in the machine direction (MD), operating a cutting unit to cut the continuous elastic film into a series of individual first film portions and individual second film portions, selectively adjusting the feed rate of the continuous elastic film upstream of the cutting unit, transferring a first film portion of the series of individual first film portions from a vacuum drum to a first pair of arms of a stretching unit, and transferring a second film portion of the series of individual second film portions from the vacuum drum to a second pair of arms of the stretching unit. Further, the method includes stretching the first film portion in the cross direction (CD) by separating the first pair of arms in the CD direction as the stretching unit rotates from a pickup position to a transfer position, stretching the second film portion in the CD direction by separating the second pair of arms in the CD direction as the stretching unit rotates from the pickup position to the transfer position, and transferring the stretched first film portion and second film portion from the stretching unit to the support web.

[0008] Operate a drive roll to feed a continuous elastic film onto a vacuum drum at a first feed rate, and while the continuous elastic film is being fed at the first feed rate, cut the continuous elastic film with a cutting unit to form a first film portion pair including a first film portion and a second film portion. After forming the first film portion pair, the drive roll can be operated to feed the continuous elastic film onto the vacuum drum at a second feed rate lower than the first feed rate. Also, the drive roll can be operated to feed the continuous elastic film onto the vacuum drum at the second feed rate for a predetermined time or for a predetermined length of the continuous elastic film. After the predetermined time has elapsed or after the predetermined length of the continuous elastic film has been fed, the drive roll can be operated to feed the continuous elastic film onto the vacuum drum at the first feed rate, and while the continuous elastic film is being fed at the first feed rate, cut the continuous elastic film with a cutting unit to form a second film portion pair including another first film portion of the series of individual first film portions and another second film portion of the series of individual second film portions.

[0009] Another first film portion is transferred from the vacuum drum to the third pair of arms of the extension unit, and another second film portion is transferred from the vacuum drum to the fourth pair of arms of the extension unit. When the extension unit rotates from the pickup position to the transfer position, by separating the third pair of arms in the CD, the another first film portion in the CD is extended. When the extension unit rotates from the pickup position to the transfer position, by separating the fourth pair of arms in the CD, the another second film portion in the CD is extended. Further, the extended another first film portion and second film portion can be transferred from the extension unit to the support web.

[0010] When transferring the extended first film portion and second film portion, and when transferring the extended another first film portion and second film portion, the extended first film portion and second film portion of the first film portion pair may be separated by a first distance on the support web in the MD, and the extended another first film portion and second film portion of the second film portion pair may be separated by a first distance on the support web in the MD. Further, the first film portion pair on the support web away from the second film portion pair in the MD may also be separated by a second distance longer than the first distance.

[0011] In the method disclosed herein, transferring the first film portion and the second film portion, and transferring the another first film portion and the second film portion from the vacuum drum include rotating the extension unit to bring the first pair of arms and the second pair of arms adjacent to the vacuum drum to remove the first film portion and the second film portion from the vacuum drum, and rotating the extension unit to bring the third pair of arms and the fourth pair of arms adjacent to the vacuum drum to remove the another first film portion and the second film portion from the vacuum drum.

[0012] In some embodiments, the extension unit rotates at a constant speed.

[0013] By supplying a rotational force to the drive roll via a servo motor, the drive roll can selectively feed a continuous elastic film onto the vacuum drum at a first feed rate or a second feed rate.

[0014] In some embodiments, the cutting unit includes a rotating cutting wheel having a first cutting element and a second cutting element fixedly disposed thereon so as to be adjacent to each other on the rotating cutting wheel. The operation of the cutting unit is to perform a cutting pair with the first cutting element and the second cutting element to form a first film portion and a second film portion, rotate the rotating cutting wheel once, and further perform another cutting pair with the first cutting element and the second cutting element to form another first film portion and another second film portion.

[0015] Some embodiments of the disclosed method include rotating the vacuum drum at a drum speed faster than the first feed rate and the second feed rate at which the continuous elastic film is fed onto the vacuum drum so that the leading edge of the continuous elastic film slides across the surface of the vacuum drum as the continuous elastic film is fed onto the vacuum drum.

[0016] According to another aspect of the present invention, an apparatus for attaching an extended elastic segment to a support web includes a drive roll configured to feed a continuous elastic film in the machine direction (MD), a vacuum drum arranged to receive the continuous elastic film from the drive roll, and a cutting unit arranged adjacent to the vacuum drum and configured to cut the continuous elastic film to produce a series of individual first film portions and individual second film portions. Further, the apparatus also includes a stretching unit for transferring the series of individual first film portions and individual second film portions from a pickup position on the vacuum drum to a transfer position on the support web. The stretching unit includes a first pair of arms configured to transfer the first film portions of the series of individual first film portions from the vacuum drum, the first pair of arms being separable in the cross direction (CD), and a second pair of arms configured to transfer the second film portions of the series of individual second film portions from the vacuum drum, the second pair of arms being separable in the CD. The first pair of arms and the second pair of arms each stretch the first film portion and the second film portion respectively within the CD by separating outwardly within the CD when moving from the pickup position to the transfer position. The drive roll is operable to variably feed the continuous elastic film onto the vacuum drum at a first feed rate and a second feed rate slower than the first feed rate.

[0017] The servo motor is configured to selectively drive the drive roll to feed the continuous elastic film onto the vacuum drum at one of the first feed rate and the second feed rate, and the controller is operably connected to the servo motor to control the operation of the servo motor.

[0018] The controller can be configured to operate the servo motor to feed out a continuous elastic film onto the vacuum drum at a first feed rate over either a first predetermined period or a first predetermined length of the continuous elastic film, and further operate the servo motor to feed out a continuous elastic film onto the vacuum drum at a second feed rate over either a second predetermined period or a second predetermined length of the continuous elastic film. The servo motor can be operated to alternately feed the continuous elastic film on the vacuum drum at the first feed rate and the second feed rate during the ongoing operation with respect to the drive roll.

[0019] In some embodiments, the cutting unit includes a rotating cutting wheel and a first cutting element and a second cutting element attached to the rotating cutting wheel. The first cutting element and the second cutting element are arranged close to each other on one side of the rotating cutting wheel.

[0020] The controller is configured such that during or immediately before the feed rate transitions from the first feed rate to the second feed rate, the first cutting element and the second cutting element are positioned to cut the continuous elastic film, and further, during the time when the feed rate is the second feed rate, the rotation of the rotating cutting wheel can be adjusted by the operation of the servo motor such that the first cutting element and the second cutting element rotate through a non-cutting range.

[0021] The stretching unit can include a third pair of arms configured to pick up another first film portion of a series of individual first film portions from the vacuum drum, the third pair of arms being separable within the CD direction, and a fourth pair of arms configured to pick up another second film portion of a series of individual second film portions from the vacuum drum, the fourth pair of arms being separable within the CD player. When the third pair of arms and the fourth pair of arms move from the pickup position to the transfer position, they separate outwardly within the CD player, causing the another first film portion and the another second film portion to stretch within the CD direction, respectively.

[0022] According to yet another aspect of the present invention, a method of attaching individual stretched film portions to a support web includes operating a drive roll to feed a continuous elastic film longitudinally (MD) onto a vacuum drum, and operating a cutting unit to form a series of individual first film portions and individual second film portions from the continuous elastic film. Further, the method includes operating a stretching unit including a plurality of pairs of arms to rotatably transfer a series of individual first film portions and individual second film portions from a pickup position on the vacuum drum to a transfer position on the support web, wherein each pair of arms of the plurality of pairs of arms secures a respective first film portion or second film portion, and separating each pair of arms of the plurality of pairs of arms in the CD between the pickup position and the transfer position to stretch each respective first film portion and second film portion in the cross direction (CD), and depositing the series of individual first film portions and individual second film portions on the support web at the transfer position. The first film portions and the second film portions of the first film portion pairs deposited on the support web are separated by a first distance in the MD, and further, a second film portion pair including another first film portion and another second film portion deposited on the support web is separated by a second distance in the MD that is longer than the first distance from the first film portion pair.

[0023] These and other advantages and features will be more readily understood from the following detailed description of the preferred embodiments for carrying out the invention, provided in connection with the accompanying drawings.

Brief Description of the Drawings

[0024] The drawings illustrate embodiments currently contemplated for carrying out the invention.

[0025] In the following drawings:

[0026]

Figure 1A

Figure 1B

[0027]

Figure 2A

[0028]

Figure 2B

[0029]

Figure 3

[0030]

Figure 4

[0031]

Figure 5

[0032]

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

[0033]

Figure 13

[0034]

Figure 14

DETAILED DESCRIPTION OF THE INVENTION

[0035] Embodiments of the present invention are directed to an apparatus for attaching stretched elastic segments to a support web and a method of operating the same. The disclosure herein is provided in sufficient detail for those skilled in the art to practice the present invention, but the physical embodiments disclosed herein are merely illustrative of the present invention and may be embodied in other specific structures. Although the preferred embodiments have been described, details may be changed without departing from the present invention.

[0036] According to an embodiment of the present invention, in the manufacture of disposable absorbent articles, instead of typical elastic strands, an extensible elastic material strip can be used. Such elastic material strips can be used to form an elasticized leg region for leg elastics or leg cuffs (right and left leg cuffs), i.e., "soft cuffs", instead of the arrangement of individual elastic strands, in order to improve the comfort and / or appearance of the user. To form elastic strip leg cuffs and then attach them to the support web, it is necessary to vary the pitch between the elastic strip leg cuffs, but existing manufacturing processes and related system equipment currently cannot accommodate such pitch changes. The improved methods and apparatuses disclosed herein can vary the pitch between adjacent elastic material portions, for example, using only a single cutting unit and an extension unit, it becomes possible to form and apply the elastic leg cuffs on the left and right of the absorbent article.

[0037] Referring now to FIG. 2A, as will be described later, a plan view of an exemplary absorbent article 100 that can be (partially) manufactured by using a method and apparatus for stretching and attaching elastic segments is provided. The absorbent article 100 illustrated in FIG. 2A is a light-loss-disabling article or pad. The light-loss-disabling absorbent article 100 generally includes a combination of a plurality of web layers, an absorbent structure, and elastic elements joined and adhered together. Specifically, the article can include a top sheet 102, a back sheet 104, an absorbent core 106, and a pair of elasticized cuffs 108.

[0038] The top sheet 102 constitutes the side of the disposable article 100 facing the skin and is thus provided as a liquid-permeable top sheet that contacts the wearer. The top sheet 102 has fibers and may be formed of a non-woven fabric. The back sheet 104 is provided on the side of the disposable article 100 that does not face the skin and faces the top sheet 102. The back sheet 104 has fibers and may be formed of a non-woven fabric.

[0039] The absorbent core 106 is disposed across the entire crotch region of the wearer and can absorb and retain liquid body exudates. The size and absorption capacity of the absorbent core 106 can vary based on the intended size of the wearer and the liquid load resulting from the intended use of the absorbent article. The absorbent core 106 can be manufactured from various materials including, but not limited to, cellulose fluff pulp, tissue layers, superabsorbent polymers (so-called superabsorbent polymer particles (SAP)), absorbent foams, absorbent nonwoven materials, etc., in various shapes.

[0040] The elasticized cuffs 108 are joined onto the topsheet 102 and are disposed at least partially along the outer lateral sides in the width direction of the disposable article 100. The cuffs 108 are substantially symmetrically aligned with respect to the axis of symmetry extending along the center in the width direction of the disposable article 100. The cuffs 108 can be formed from strips of elastic material joined to the topsheet 102 via an adhesive or the like, and are disposed on the skin-facing surface of the topsheet 102 or between the topsheet 102 and the backsheet 104. The elasticized cuffs 108 form a wall that bulges towards the skin-facing side along the outer edge of the absorbent core 106, preventing exudates from leaking laterally.

[0041] Another example of an exemplary absorbent article 110 that can be (partially) manufactured by using a method and apparatus for stretching an elastic segment and attaching it to a support web is shown in FIG. 2B. The absorbent article 110 illustrated in FIG. 2B is a "pant-type" article such as a child training pant type or an adult incontinence pant type garment. Generally, the pant-type article 110 includes a combination of a plurality of web layers joined and bonded to form a waist opening and leg openings, an absorbent structure, and elastic elements, similar to shorts. The article 110 includes a front waistline region 112, a crotch region 114, and a rear waistline region 116. The front waistline region 112 is the portion that contacts the front waistline region (abdomen) of the wearer. The rear waistline region 116 is the portion that contacts the rear waistline region (back) of the wearer. The crotch region 114 is disposed between the front waistline region 102 and the rear waistline region 116.

[0042] The article 100 includes an absorbent core 118 that extends across the entire crotch region 114 and extends toward at least one of the front waistline region 112 and the rear waistline region 116. The illustrated absorbent core 118 is disposed across the front waistline region 112, the crotch region 114, and the rear waistline region 116 and can absorb and retain liquid body exudates.

[0043] A liquid-permeable topsheet 120 is provided and constitutes the side of the disposable article 110 facing the skin, and thus contacts the wearer. The topsheet 120 is disposed across the front waistline region 112, the crotch region 114, and the rear waistline region 116. A backsheet 122 is provided on the side of the disposable article 110 that does not face the skin and is opposite the topsheet 120 and is generally disposed across the front waistline region 112, the crotch region 114, and the rear waistline region 116.

[0044] The pair of elasticized cuffs 124 is joined onto the topsheet 120 and is disposed at least partially along the outer lateral sides in the width direction of the disposable article 110, and forms a wall that bulges toward the skin-facing side along the outer edge of the absorbent core 108, thereby preventing exudates from leaking laterally. The cuffs 124 are aligned substantially symmetrically with respect to a symmetry axis extending along the center in the width direction of the disposable article 110. The cuffs 124 can be formed from strips of elastic material that are joined to the topsheet 120 via an adhesive or the like, and are disposed on the skin-facing surface of the topsheet 120, or are disposed between the topsheet 120 and the backsheet 122.

[0045] Next, referring to FIG. 3, in one implementation, after forming strips of elastic material that constitute the cuffs 108, 124 of the articles 100, 110 illustrated in FIGS. 2A and 2B, as part of the process of manufacturing the articles 100, 110, a schematic view of an exemplary apparatus 10 is shown that can stretch the elastic strips and affix them to a moving support web (e.g., topsheets 102, 120). The main components of the apparatus 10 include a drive roll 12, a vacuum roll or drum 14, a cutting unit 16, an elastic stretching unit 18, and a transfer drum 20, although it will be understood that the apparatus 10 can also include additional components such as various actuators, sensors, material feeds, etc. that enable the desired operations.

[0046] In the operation of the apparatus 10, for example, a continuous elastic film 22 formed of an elastic foamed polyurethane material is sent to the apparatus 10 by, for example, pulling the elastic film 22 from a material roll and arranging a roll (not shown) that supplies the elastic film 22 to the apparatus 10 for subsequent processing. The elastic film 22 is sent across a dancer roll arrangement 24, which senses the tension of the elastic film 22 between the arrangement of the roll and the drive roll 12 and operates to keep the tension of the elastic film 22 constant. Next, the drive roll 12 sends the elastic film 22 onto the vacuum drum 14, and the elastic film 22 moves in the longitudinal direction (generally indicated by 26). The cutting unit 16 acts on the elastic film 22 to form a series of individual film portions that can be characterized as an individual first film portion 28 and an individual second film portion 30, for example, to form the left and right elasticized cuffs of the absorbent article. The individual film portions 28, 30 are maintained on the vacuum drum 14 that rotates about a rotation axis until the film portions 28, 30 are arranged at the pickup position 32. At the pickup position 32, the stretching unit 18 operates to remove the film portions 28, 30 from the vacuum drum 14, and when the stretching unit rotates, the film portions 28, 30 are held on the stretching unit 18. The stretching unit 18 holds the film portions 28, 30 thereon when rotating from the pickup position 32 to the transfer position 34, and the stretching unit 18 operates to stretch the film portions 28, 30 in the lateral direction (generally indicated by 36 in FIG. 4) when moving from the pickup position 32 to the transfer position 34, which will be described in more detail below.

[0047] When the stretched film portions 28, 30 reach the transfer position 34, the stretched film portions 28, 30 are transferred onto the support web 38 that is moving in the longitudinal direction 26 from the stretching unit 18. The adhesive applicator 40 is disposed on the incoming support web 38 and may be arranged such that a row of nozzles or other applicators extends (in the transverse direction 36) across the entire support web 38. The applicator 40 can lay down stripes of adhesive in a desired intermittent pattern at the positions where the elastic film portions 28, 30 are to be disposed on the support web 38. The transfer drum 20 positioned on the opposite side of the support web 38 (i.e., the side opposite the stretching unit 18) assists in the transfer of the stretched film portions 28, 30 onto the support web 38, and the support web 38 passes between the transfer drum 20 and the stretching unit 18 at the transfer position 34 and receives the stretched elastic portions 28, 30 from the stretching unit 18 at the position where the adhesive is applied. Next, the support web 38 with the stretched film portions 28, 30 held thereon advances downstream in the longitudinal direction 26 and can undergo further processing to complete the assembly of the absorbent article.

[0048] Next, continuing to refer to FIG. 3 and referring to FIG. 4, a perspective view of a portion of the apparatus 10 is provided to further illustrate its individual components. As described above, the continuous elastic film 22 is sent to the apparatus 10, specifically to its drive roll 12. The continuous elastic film 22 is received on the drive roll 12 and held thereon via an adjacent support roll 42 positioned on a spring-biased arm 44 that sandwiches the film against the drive roll 12. The drive roll 12 is supported on a drive shaft 46 that receives rotational force from a rotational actuator 48 (hereinafter referred to as the "servo motor 48") that can be provided as a servo motor in one embodiment. Through a servo cam configuration / process, the servo motor 48 controls the rotational speed of the drive roll 12, and thereby also controls the feed rate at which the drive roll 12 supplies the continuous elastic film 22 to the vacuum drum 14, which will be described in detail below. In an alternative embodiment, instead of a servo motor, other types of rotational actuators such as a stepping motor, or another electric motor, that selectively operates to control the rotational speed of the drive roll 12 and thereby also control the feed rate at which the drive roll 12 supplies the continuous elastic film 22 to the vacuum drum 14 can also be used.

[0049] The vacuum drum 14 is positioned to receive the continuous elastic film 22 from the drive roll 12 after it passes through this drive roll, and the cutting unit 16 is positioned adjacent to the vacuum drum 14 and performs a cutting operation on the continuous elastic film 22, thereby forming individual elastic film portions 28, 30. The vacuum drum 14 and the cutting unit 16 are drivable via a common servo motor 50, and this servo motor 50 provides rotational force to the cutting wheel 52 of the cutting unit 16 and the vacuum drum 14 via a timing belt (not shown) that extends between the servo motor 50, the cutting unit 16, and the vacuum drum 14. In one embodiment, both the vacuum drum 14 and the cutting unit 16 rotate at a constant speed.

[0050] The cutting unit 16 rotates about an axis such that a pair of cutting knives 56 attached to the cutting wheel 52 are positioned in periodic contact with the continuous elastic film 22. The cutting knives 56 rotate into contact with the outer periphery of the vacuum drum 14 and use the drum as an anvil to cut the individual film portions 28, 30 from the continuous elastic film 22. The pair of cutting knives 56 are positioned close to each other so as to quickly and continuously cut the continuous elastic film 22, performing two cuts on the elastic film 22 to create a pair of elastic film portions, namely, a first film portion 28 and a second film portion 30. As a non-limiting example, the cutting knives 56 are arranged on the cutting wheel 52 and rotate at a speed that enables the cutting of the continuous elastic film 22 to form film portions 28, 30 having a length in the longitudinal direction 26 of 20 to 80 mm. After one pair of cuts is completed, the cutting knives 56 continue to rotate about the axis and make one full rotation before being carried back to the cutting position again. In an alternative embodiment, it is contemplated that the cutting unit 16 may be provided with only a single cutting knife or three or more cutting knives. In such a case, the rotational speed of the cutting unit 16 may be selectively changed so as to cut the continuous elastic film 22 to form film portions 28, 30 of a desired length.

[0051] Individual film portions 28, 30 cut from the continuous elastic film 22 are fixed to the vacuum drum 14 after being cut by the cutting unit 16. Vacuum pipes 58, 60 are provided to draw a vacuum into an internal vacuum chamber (not shown) of the vacuum drum 14. In one embodiment, the pipe 58 draws a low vacuum into the vacuum chamber to draw the continuous elastic film 22 onto the vacuum drum 14 (while allowing the film 22 to slide on the drum 14), and the pipe 60 draws a high vacuum into the vacuum chamber to hold the cut film portions 28, 30 in a fixed position on the drum 20. As seen in FIG. 4, the outer surface 62 of the vacuum drum 14 is in fluid communication with the internal vacuum chamber and includes a plurality of holes or slots 64 into which the vacuum is drawn. Accordingly, the vacuum drum 14 is configured to hold the elastic film portions 28, 30 on the outer periphery of the vacuum drum 14 as the vacuum drum rotates from the position where the film portions 28, 30 are cut from the continuous film to the position where the film portions 28, 30 are picked up from the vacuum drum 14 by the stretching unit 18, i.e., the pickup position 32.

[0052] The structure of the extension unit 18 is shown in FIG. 4 and also in FIG. 5, and generally consists of two electric wheels, or disks 66, spaced apart from each other in the lateral direction 36 (i.e., wheels 66 rotated and driven by respective servo motors 68). The wheels 66 rotate about a rotation axis 70 that intersects each other at an intermediate point between the two wheels 66. In one embodiment, the extension wheels 66 rotate about the axis 70 at a speed similar to, or the same as, the speed of the vacuum drum 14 and the cutting unit 16. Each wheel 66 has an arm 72 extending radially outward therefrom. In the exemplary embodiment, each wheel 66 includes four arms 72 attached thereto. As will be referred to below, the arms 72 of one wheel are aligned with the corresponding arms 72 of the opposite wheel and cooperate with each other to form a "pair of arms" that pick up the elastic film portions 28, 30 from the vacuum drum 14. Thus, the arms 72 are considered to provide / form a first pair of arms 74, a second pair of arms 76, a third pair of arms 78, and a fourth pair of arms 80. As seen in FIG. 4, the first pair of arms 74 and the second pair of arms 76 are arranged close to each other on one side of the extension unit 18 (i.e., one side of the wheel 66), and the third pair of arms 78 and the fourth pair of arms 80 are arranged close to each other on the opposite side of the extension unit 18 (i.e., 180° from the first and second pairs of arms 74, 76).

[0053] At the ends of each arm 72, there are gripping surfaces 82 for gripping the ends of the elastic film portions 28, 30, whereby the elastic film portions can be picked up from the vacuum drum 14 and held in place while the elastic film portions 28, 30 are stretched in the lateral direction 36. In the illustrated embodiment, the gripping surfaces 82 exert a gripping force and a holding force on the ends of the elastic film portions 28, 30 by vacuum, although it will also be understood that a mechanical hook provided on the gripping surface 82, or an interference-type structure (e.g., a pin), can alternatively be used to provide the gripping force and the holding force. A series of openings 84 are formed in the gripping surface 82 to supply a vacuum force to the gripping surface 82, through which a vacuum is provided. A pair of vacuum pipes 86 that draw a vacuum into an internal vacuum chamber (not shown) of each wheel 66 are provided in the extension unit 18. The openings 84 on the gripping surface 82 of each arm 72 are in fluid communication with the internal vacuum chamber of the respective wheel 66, whereby a vacuum can be drawn through the openings 84. At the pickup position 32 where the elastic film portions 28, 30 are drawn out from the vacuum drum 14, the ends of the elastic film portions 28, 30 are positioned with respect to the respective pairs of arms 72 of the extension unit 18 such that the film portions 28, 30 cover the openings 84 of the gripping surface 82 of the arms 72, and the elastic film portions 28, 30 are pressed onto the gripping surface 82 by the vacuum gripping effect. The intensity of the vacuum force applied to the elastic film portions 28, 30 can be adjusted during the operation of the extension unit 18, for example, by selectively operating a vacuum pump (not shown) that supplies a vacuum into the wheels 66 (via the pipes 86).

[0054] During the operation of the stretching unit 18, the two wheels 66 are pulled out during rotation by respective motors 68 driven by a controller 88 (FIG. 3). The controller 88 synchronizes the operations of the respective motors 68 to prevent the elastic film portions 28, 30 held by the respective pairs of arms 72 from eventually skewing due to differences in the rotational speeds of the wheels 66. As the wheels 66 rotate about their axes 70, the spacing between the respective pairs of arms 72 of the arms 74, 76, 78, 80 diverges or converges and changes in the lateral direction 36 depending on the angular position of the arms 72 about the axis of rotation. That is, the mutually inclined or angled arrangement of the axes 70 of the wheels 66 causes the outer circumferences of the wheels 66, and thus the paths along which the arms 72 move thereon, to alternately diverge and converge such that they are "close" when adjacent to the vacuum drum 14 at the pickup position 32 and "separated" when adjacent to the transfer drum 20 / support web 38 at the transfer position 34. As shown in the preferred example of FIG. 5, the arms 72 of each arm pair 74, 76, 78, 80 are separated by a first distance D1 in the lateral direction 36 when adjacent to the vacuum drum 14 at the pickup position 32, and further separated by a second distance D2 that is longer than the first distance D1 in the lateral direction 36 when adjacent to the transfer drum 20 and the support web 38 at the transfer position 34. Thereby, the pairs of arms 74, 76, 78, 80 function as tensile members by which these elastic film portions are stretched as the elastic film portions 28, 30 move from the pickup position 32 to the transfer position 34.

[0055] According to an embodiment, the apparatus 10 operates to form, stretch, and attach the individual elastic film portions 28, 30 to the support web 38, and the apparatus 10 is controlled to vary the pitch between the elastic film portions 28, 30 so that they can be attached to the support web 38. Thus, in one exemplary implementation, the apparatus 10 can be utilized in the process of forming an absorbent article in which the elastic film portions are to be attached as the left and right elastic leg cuffs of the absorbent article, as illustrated in FIGS. 2A and 2B.

[0056] Here, continuing to refer to FIGS. 3-5 and referring to FIGS. 6-12, a method is shown for forming, stretching, and attaching individual stretched film portions 28, 30 in accordance with an embodiment of the present invention to a support web 38. First, as shown in FIG. 6, the drive roll 12 receives the continuous elastic film 22 that can be supplied to the roll after the film is advanced by another roll (not shown) and passed over the dancer roll arrangement 24. The rotation of the drive roll 12 is controlled via the servo motor 48 and associated controller, which in the illustrated embodiment is the controller 88, but could be another controller. The controller 88 and the servo motor 48 operate the drive roll 12 to feed the continuous elastic film 22 to the vacuum drum 14 at a first feed rate V1. The feed rate V1 at which the continuous elastic film 22 is fed to the vacuum surface 62 of the rotating vacuum drum 14 is lower than the speed of the vacuum drum 14 moving at a constant relatively high surface speed VD. Thus, the incoming continuous elastic film 22 can "slip" along the surface 62 of the vacuum drum 14 to perform a slip-and-cut type film cutting operation.

[0057] While the continuous elastic film 22 is being fed at the feed rate V1 and translating toward the cutting position 90 between the vacuum drum 14 and the cutting unit 16, the cutting unit 16 rotates to a position where the pair of cutting knives 56 thereon contacts the continuous elastic film 22. Preferably, the cutting knives 56 move at a speed similar to, or the same as, the speed of the vacuum drum surface 62 (i.e., the vacuum drum speed VD). The pair of cutting knives 56 makes a rapid and continuous pair of cuts on the continuous elastic film 22, forming the first film portion 28 and the second film portion 30 cut from the remaining film of the continuous elastic film 22. Hereinafter, the first film portion 28 and the second film portion 30 are collectively referred to as the first film portion pair 92.

[0058] Substantially simultaneously with (i.e., either immediately before, during, or immediately after) the cutting knife 56 cutting the first film section pair 92 from the remaining film of the continuous elastic film 22, the controller 88 and the servo motor 48 operate to control the drive roll 12 to reduce the feed rate at which the continuous elastic film 22 is fed to the vacuum drum 14. As can be seen in FIG. 7, the drive roll 12 operates to reduce the feed rate of the continuous elastic film 22 to a second feed rate V2 that is lower than the first feed rate V1. When the feed rate of the continuous elastic film 22 is reduced to the second feed rate V2, the first film section pair 92 can rotate further along the surface 62 of the vacuum drum 14 before the continuous elastic film 22 advances again to the cutting position 90 between the vacuum drum 14 and the cutting unit 16. Thus, the first film section pair 92 is spaced from the next, i.e., the second film section pair 94 (i.e., another first film section 28b and another second film section 30b that form the second film section pair 94), that is cut from the continuous elastic film 22. While the continuous elastic film 22 is fed to the vacuum drum 14 at the feed rate V2, the cutting unit 16 continues to rotate and the pair of cutting knives 56 rotates about the cutting wheel 52 through a range of non-cutting positions.

[0059] As shown in FIG. 8 here, while the continuous elastic film 22 is being fed at the feed rate V2, the first film portion pair 92 further rotates about the surface 62 of the vacuum drum 14, and the position of the cutting knife 56 approaches again to the cutting position 90 between the vacuum drum 14 and the cutting unit 16. However, during this period, since the continuous elastic film 22 is being fed at the low feed rate V2, a continuous elastic film 22 of an appropriate length that enables the formation of the second film portion pair 94 has not yet reached the cutting position 90 between the vacuum drum 14 and the cutting unit 16. At this point, in order to cause the continuous elastic film 22 to be fed to the vacuum drum 14 at the feed rate V1 again, the controller 88 determines the timing at which the feed rate of the continuous elastic film 22 should be increased. According to an embodiment, the determination by the controller 88 may be a time-based determination or a measurement-based determination. That is, the controller 88, after a predetermined period (monitored by the controller 88) has elapsed while the drive roll 12 is operating at the feed rate V2, or after a certain specific length of the continuous elastic film 22 has been conveyed in the longitudinal direction 26 while the drive roll 12 is operating at the feed rate V2 (measured by a related sensor and relayed to the controller 88), can, via the operation of the servo motor 48, cause the continuous elastic film 22 to be conveyed again to the drive roll 12 at the feed rate V1. To make the above determination(s), the controller 88 can include a processor 88a and a memory 88b. The processor 88a executes the computing function and control function of the controller 88 via the execution of one or more programs that may be included in the memory 88b. The memory 88b stores the values stored therein (such as a predetermined period related to the length of the film), as well as the programs for execution.

[0060] When it is determined by the controller 88 to cause the drive roll 12 to convey the continuous elastic film 22 back to the vacuum drum 14 at the feed rate V1, the controller 88 can control the operation of the servo motor 48 to cause the drive roll 12 to convey the continuous elastic film 22 to the vacuum drum 14 again at the feed rate V1. Referring now to FIG. 9, the controller 88 currently operates the servo motor 48 to cause the drive roll 12 to feed the continuous elastic film 22 to the vacuum drum 14 at the first feed rate V1. While the continuous elastic film 22 is being fed at the feed rate V1 and is traveling translationally toward the cutting position 90, the cutting unit 16 rotates back again to a position where the pair of cutting knives 56 thereon are brought into contact with the continuous elastic film 22, and in accordance with the slip-and-cut type film cutting operation as described above, another first film portion 28b and another second film portion 30b (i.e., the second film portion pair 94) are formed which are cut from the remaining film of the continuous elastic film 22.

[0061] Substantially simultaneously with the cutting of the second film section pair 94, the first film section pair 92 reaches the pickup position 32 where the first and second film sections 28, 30 are pulled out from the vacuum drum 14 by the extension unit 18. That is, the first pair of arms 74 and the second pair of arms 76 rotate to positions adjacent to the pickup position 32 simultaneously with the arrival of the first film section pair 92 at the pickup position 32. The first film section 28 is pulled out from the vacuum drum 14 by the first pair of arms 74, and then sequentially, the second film section 30 is pulled out from the vacuum drum 14 by the second pair of arms 76. When pulling out the first and second film sections 28, 30 from the vacuum drum 14 respectively, the respective arms 72 of the first and second pairs or arms 74, 76 are positioned in a "proximity" arrangement (separated by a distance D1 as seen in FIG. 5), whereby the gripping surfaces 82 at the radially outer ends of each arm 72 are arranged adjacent to the respective ends (in the intersecting direction) of the film sections 28, 30 to be picked up thereby. As indicated above, next, the film sections 28, 30 are held on the gripping surfaces 82 of the arms 72 via a vacuum or the like communicating through the openings 84 formed in the gripping surfaces 82. The first film section 28 spreads between the arms 72 of the first arm pair 74, and further, the second film section 30 spreads between the arms 72 of the second arm pair 76.

[0062] The second film portion pair 94 is cut from the continuous elastic film 22, and substantially simultaneously with the first film portion pair 92 being picked up by the first and second pairs of arms 74, 76 of the extension unit 18, the controller 88 and the servo motor 48 operate to control the drive roll 12 to supply the continuous elastic film 22 back to the vacuum drum 14 at the lower second feed rate V2. While this is occurring and while the drive roll 12 continues to operate the apparatus with the continuous elastic film 22 being fed to the vacuum drum 14 at the feed rate V2, as seen in FIG. 10, the second film portion pair 94 further rotates along the surface of the vacuum drum 14 toward the pickup position 32, and the first film portion pair 92 continues to rotate on the extension unit 18 from the pickup position 32 toward the transfer position 34 while being held by the first and second pairs of arms 74, 76. When the first film portion pair 92 rotates on the extension unit 18 toward the transfer position 34, the first pair of arms 74 and the second pair of arms 76 each begin to separate in the lateral direction 36 in order to extend the first and second film portions 28, 30, respectively. That is, when the first and second pairs of arms 74, 76 rotate on the extension unit 18 from the pickup position 32 to the transfer position 34, the separation distance between the arms 72 in each arm pair 74, 76 increases from a first distance D1 in the lateral direction 36 to a second distance D2 in the lateral direction 36 so as to extend the first and second film portions 28, 30 in the lateral direction 36 (see FIG. 5).

[0063] As shown in FIG. 11, when the extension unit 18 rotates so that the first film part pair 92 reaches the transfer position 34, the first and second film parts 28, 30 are deposited on the support web 38 by the first and second pairs of arms 74, 76 of the extension unit 18. When the arms 72 of the first and second pairs of arms 74, 76 reach the transfer position 34 and these arms are positioned in a "separated" arrangement (separated by the distance D2 in FIG. 5), the first and second film parts 28, 30 are deposited on the support web 38 in an extended state. As described above, the first and second film parts 28, 30 are deposited at positions on the support web 38 where the adhesive has been pre-applied, whereby the film parts 28, 30 are held at predetermined positions on this support web after being deposited on the support web 38. The presence of the transfer drum 20 on the side of the support web 38 opposite to the extension unit 18 facilitates the transfer of the extended first and second film parts 28, 30 onto the support web 38, and the transfer drum 20 can firmly position the extended first and second film parts 28, 30 on the adhesive.

[0064] Also, as seen in FIG. 11, in connection with the first film section pair 92 reaching the transfer position 34, the second film section pair 94 rotates about the vacuum drum 14 and reaches the pickup position 32. As previously described with respect to the first film section pair 92, the first and second film sections 28b, 30b of the second film section pair 94 are pulled out from the vacuum drum 14 by the extension unit 18 when they reach the pickup position 32. To pick up from the vacuum drum 14, the third pair of arms 78 and the fourth pair of arms 80 of the extension unit 18 rotate to a position adjacent to the pickup position 32 simultaneously with the second film section pair 94 reaching the pickup position 32. The first film section 28b is pulled out from the vacuum drum 14 by the third pair of arms 78, and then successively, the second film section 30b is pulled out from the vacuum drum 14 by the fourth pair of arms 80. When pulling out the second film section pair 94 from the vacuum drum 14, the arms 72 of each of the third and fourth arm pairs are positioned in a "proximity" arrangement (separated by a distance D1 as seen in FIG. 5), whereby the gripping surface 82 at the radially outer end of each arm 72 is arranged adjacent to the respective ends (in the cross direction) of the film sections 28b, 30b to be picked up thereby. As indicated previously, next, the film sections 28b, 30b are held on the gripping surface 82 of the arm via a vacuum or the like communicating through the openings 84 formed in the gripping surface 82, the first film section 28b spreads between the arms 72 of the third arm pair 78, and further, the second film section 30b spreads between the arms 72 of the fourth arm pair 80.

[0065] When the first film section pair 92 arrives at the transfer position 34 and, almost simultaneously, the second film section pair 94 arrives at the pickup position 32, the controller 88 determines whether the drive roll 12 should return from transporting the continuous elastic film 22 to the vacuum drum 14 at the feed rate V2 to transporting the continuous elastic film 22 to the vacuum drum 14 at the feed rate V1. As previously described, the determination made by the controller 88 can be either a time-based determination or a measurement-based determination. The controller 88 causes the drive roll 12 to transport the continuous elastic film 22 back to the vacuum drum 14 at the feed rate V1 when a predetermined period of time has elapsed or when a certain length of the continuous elastic film 22 has been transported in the longitudinal direction 26.

[0066] Referring now to FIG. 12, a state is illustrated in which the second film section pair 94 has rotated about the stretching unit 18 and arrived at the transfer position 34. During this time, the feed rate is changed (returned from V1 to V2) and the third film section pair 96 is cut from the continuous elastic film 22. When the transfer position 34 is reached, the first and second film sections 28b, 30b of the second film section pair 94 are deposited on the support web 38 by the third and fourth pairs of arms 78, 80 of the stretching unit 18. When the arms 72 of each of the third and fourth pairs of arms 78, 80 reach the transfer position 34 and these arms are positioned in a "separated" arrangement (separated by the distance D2 in FIG. 5B), the first and second film sections 28b, 30b are deposited on the support web 38 in a stretched state. As previously described, the first and second film sections 28b, 30b are deposited at positions on the support web 38 on which the adhesive has been pre-applied, whereby the film sections 28b, 30b are held at predetermined positions on this support web after being deposited on the support web 38.

[0067] By executing the operation steps of the method illustrated in FIGS. 6 to 12, the pitch between the individual extended elastic film portions 28, 30, 28b, 30b attached to the support web 38 changes by a desired amount in a desired manner. Specifically, by selectively controlling the feed rate at which the drive roll 12 feeds the continuous elastic film 22 to the vacuum drum 14, that is, by switching the feed rate between a first feed rate V1 and a second feed rate V2, the pitch between successive pairs of film portions (a first film portion pair 92 and a second film portion pair 94) cut from the continuous elastic film 22 can be controlled.

[0068] The change in pitch between the cut elastic film portions 28, 30, 28b, 30b attached on the support web 38 is best shown in FIGS. 13 and 14, and the elastic film portions 28, 30, 28b, 30b are arranged on the support web 38 according to various product configurations. As shown herein, for a series of individual first film portions 28, 28b and individual second film portions 30, 30b attached to the support web 38, the first film portion 28 and the second film portion 30 of the first film portion pair 92 are separated from each other by a first distance in the longitudinal direction L1. As previously described, the first film portion 28 and the second film portion 30 of the first film portion pair 92 are attached onto the support web 38 by the first and second pairs of arms 74, 76 of the stretching unit 18, and the distance, or pitch L1, between the first film portion 28 and the second film portion 30 is determined based on the separation interval between the first and second pairs of arms 74, 76 on the stretching unit 18. Similar to the first film portion pair 92, the (another) first film portion 28b and the (another) second film portion 30b in the second film portion pair 94 are also separated from each other by a first distance L1 in the longitudinal direction. The (another) first film portion 28b and the (another) second film portion 30b of the second film portion pair 94 are attached onto the support web 38 by the third and fourth pairs of arms 78, 80 of the stretching unit 18, and the distance L1 between the (another) first film portion 28b and the (another) second film portion 30b is determined based on the separation interval between the third and fourth pairs of arms 78, 80 on the stretching unit 18.

[0069] The distance L1 between the film parts in the first film part pair 92 and between the film parts in the second film part pair 94 is the distance L1, whereas the distance, or pitch, between the first film part pair 92 and the second film part pair 94 (and between the second film part pair 94 and the third film part pair 96) is a longer distance L2. As described above, compared with the distance (L1) between the first and second film parts 28, 30, 28b, 30b within each film part pair, due to the increased distance (L2) between the first film part pair 92 and the second film part pair 94, for at least most of the period between the time when the first film part pair 92 is cut and the time when the second film part pair 94 is cut, the feeding speed of the continuous elastic film 22 decreases (from the higher feeding speed V1) to the feeding speed V2. During this period, by operating the drive roll 12 to decrease the feeding speed, the first film part pair 92 can move further away vertically from the second film part pair 94, so that the distance or pitch L2 increases.

[0070] As seen in FIG. 13, the positioning of the individual stretched elastic film parts 28, 30, 28b, 30b on the support web 38 may correspond to the position of the elastic leg cuffs 114 to be provided for a series of absorbent articles manufactured according to a continuous process, such as the pant-type article 110 shown in FIG. 2B. The first and second film parts 28, 30, 28b, 30b in the film part pair form the left and right elastic cuff members of one absorbent article and, accordingly, are spaced apart by a distance L1. Further, the film part pair 92 (left and right elastic cuff members) of one absorbent article is separated by a distance L2 from the film part pair 94 (left and right elastic cuff members) of the next / adjacent absorbent article. It will be understood that the distances L1 and L2 depend on the size of the absorbent articles to be manufactured, which is determined by the desired / required spacing or pitch between the left and right elastic cuff members and the desired / required spacing or pitch between adjacent absorbent articles.

[0071] FIG. 14 shows the positioning of the individual stretched elastic film portions 28, 30, 28b, 30b on the support web 38 corresponding to the position of the elastic leg cuffs 114 provided on a series of incontinent absorbent articles (e.g., the incontinent absorbent article 100 shown in FIG. 2A) manufactured according to a continuous process. The first and second film portions 28, 30, 28b, 30b of each film portion pair 92, 94, 96 are spaced apart by a distance L1, while the film portion pair 92 is separated from the film portion pair 94, and further, the film portion pair 94 is separated from the film portion pair 96 by a distance L2. The first and second film portions 28, 30, 28b, 30b of each film portion pair 92, 94, 96 form the elastic cuff members of adjacent absorbent articles. For example, the first and second film portions 28, 30 of the film portion pair 92 form the left and right elastic cuff members of adjacent articles, the first and second film portions 28b, 30b of the film portion pair 94 form the left and right elastic cuff members of adjacent articles, and a cut is made between the first and second film portions 28, 30, 28b, 30b of the film portion pair (between portions 28, 30 and between portions 28b, 30b) to form individual articles. It will be appreciated that the distances L1 and L2 depend on the size of the absorbent articles to be manufactured, which are determined by the desired / required spacing or pitch between the left and right elastic cuff members and the desired / required spacing or pitch between adjacent absorbent articles.

[0072] According to the embodiment, by repositioning the extension unit arm 72 on the extension wheel 66 or reconfiguring the cutting unit 16, and / or by changing the feed rate at which the continuous elastic film 22 is fed to the vacuum drum 14, etc., the distances L1 and L2 can be changed through the reconfiguration of the apparatus 10 shown and described in FIGS. 3 - 5. Further, it will be understood that alternative extension wheels can be provided to the apparatus 10 to enable the changing of the distances of L1 and / or L2. For example, the extension unit 18 in FIGS. 4 and 5 generally includes two wheels 66 each driven by an associated servo motor 68, and each wheel 66 includes four arms 72 disposed on the upper portion such that they are on opposite sides of the wheel (such that the first and second pairs of arms 74, 76 are fixedly arranged 180° apart from the third and fourth pairs of arms 78, 80), although it will be understood that alternative structures of the extension unit 18 can be provided in which the angular positions of the first and second pairs of arms 74, 76 relative to the third and fourth pairs of arms 78, 80 can vary. In such an embodiment, additional extension wheels and servo motors can be provided to the extension unit to enable the rotation and positioning of the first and second pairs of arms 74, 76 to be controllable separately from the rotation and positioning of the third and fourth pairs of arms 78, 80. With such a structure of the extension unit, it should be possible to change the distance L2 when applying the film portion onto the support web, such as when implementing a change in the product size of the absorbent article.

[0073] Advantageously, in this way, embodiments of the present invention provide a method and apparatus for forming, stretching, and applying an elastic film portion or segment on a support web such that it can be used in an elastic leg cuff in the manufacture of an absorbent article. By selectively controlling the feed rate when continuously feeding an elastic film longitudinally and cutting, stretching, and applying the formed elastic segments therefrom, the spacing between the elastic segments applied to the support web can be varied in a desired manner. A pair of elastic segments or cuffs for a first absorbent article can be spaced apart by a desired first distance on the support web, while a pair of elastic segments or cuffs for the next absorbent article can be spaced apart by a desired second distance that is longer than the first distance from the pair of elastic segments or cuffs for the first absorbent article. This method and apparatus provide for the formation and application of left and right elastic leg cuffs for each absorbent article with a varying pitch in this way using only a single cutting unit and a single stretching unit so as to minimize the hardware costs within the apparatus.

[0074] Accordingly, according to one embodiment of the present invention, a method of applying individual stretched film portions to a support web includes conveying a continuous elastic film in a longitudinal direction (MD), operating a cutting unit to cut the continuous elastic film into a series of individual first film portions and individual second film portions, selectively adjusting the feed rate of the continuous elastic film upstream of the cutting unit, transferring a first film portion of the series of individual first film portions from a vacuum drum to a first pair of arms of a stretching unit, and transferring a second film portion of the series of individual second film portions from the vacuum drum to a second pair of arms of the stretching unit. Further, the method includes stretching the first film portion in the cross direction (CD) by separating the first pair of arms in the CD as the stretching unit rotates from a pickup position to a transfer position, stretching the second film portion in the CD by separating the second pair of arms in the CD as the stretching unit rotates from the pickup position to the transfer position, and transferring the stretched first film portion and second film portion from the stretching unit to the support web.

[0075] According to another aspect of the present invention, an apparatus for attaching an extended elastic segment to a support web includes a drive roll configured to feed a continuous elastic film in the machine direction (MD), a vacuum drum arranged to receive the continuous elastic film from the drive roll, and a cutting unit arranged adjacent to the vacuum drum and configured to cut the continuous elastic film to produce a series of individual first film portions and individual second film portions. Further, the apparatus also includes an extension unit for transferring the series of individual first film portions and individual second film portions from a pick-up position on the vacuum drum to a transfer position on the support web. The extension unit includes a first pair of arms configured to transfer the first film portions of the series of individual first film portions from the vacuum drum, the first pair of arms being separable in the cross direction (CD), and a second pair of arms configured to transfer the second film portions of the series of individual second film portions from the vacuum drum, the second pair of arms being separable in the CD. The first pair of arms and the second pair of arms each extend the first film portion and the second film portion respectively within the CD by separating outwardly within the CD when moving from the pick-up position to the transfer position. The drive roll is operable to variably feed the continuous elastic film onto the vacuum drum at a first feed rate and a second feed rate slower than the first feed rate.

[0076] According to yet another aspect of the present invention, a method of attaching individual stretched film portions to a support web includes operating a drive roll to feed a continuous elastic film longitudinally (MD) onto a vacuum drum, and operating a cutting unit to form a series of individual first film portions and individual second film portions from the continuous elastic film. Further, the method includes operating a stretching unit including a plurality of pairs of arms to rotatably transfer a series of individual first film portions and individual second film portions from a pickup position on the vacuum drum to a transfer position on the support web, each pair of arms of the plurality of pairs of arms fixing a respective first film portion or second film portion, and separating each pair of arms of the plurality of pairs of arms in the cross direction (CD) between the pickup position and the transfer position to stretch each respective first film portion and second film portion in the cross direction (CD), and depositing the series of individual first film portions and individual second film portions on the support web at the transfer position. The first film portions and second film portions of a first film portion pair deposited on the support web are separated by a first distance in the MD, and further, a second film portion pair including another first film portion and another second film portion deposited on the support web is separated by a second distance in the MD that is longer than the first distance from the first film portion pair.

[0077] Although the present invention has been described in detail in connection with a limited number of embodiments, it will be readily understood that the present invention is not limited to such disclosed embodiments. Rather, the present invention can be modified to incorporate any number of variations, alterations, substitutions, or equivalent arrangements not heretofore described, provided they are within the spirit and scope of the present invention. Further, while various embodiments of the present invention have been described, it is to be understood that aspects of the present invention may include only a portion of the described embodiments. Accordingly, the present invention is not to be limited by the foregoing description, but is to be defined only by the appended claims.

Claims

1. A method of attaching individual stretched film portions to a support web, comprising: conveying a continuous elastic film in the longitudinal direction (MD); operating a cutting unit to cut the continuous elastic film into a series of individual first film portions and individual second film portions; selectively adjusting the feed rate of the continuous elastic film upstream of the cutting unit; transferring a first film portion of the series of individual first film portions from a vacuum drum to a first pair of arms of a stretching unit; transferring a second film portion of the series of individual second film portions from the vacuum drum to a second pair of arms of the stretching unit; stretching the first film portion in the CD by separating the first pair of arms in the cross direction (CD) as the stretching unit rotates from a pickup position to a transfer position; stretching the second film portion in the CD by separating the second pair of arms in the CD as the stretching unit rotates from the pickup position to the transfer position; transferring the stretched first and second film portions from the stretching unit to the support web; A method comprising the above steps.

2. operating a drive roll to feed the continuous elastic film onto the vacuum drum at a first feed rate; while the continuous elastic film is being fed at the first feed rate, cutting the continuous elastic film with the cutting unit to form a first pair of film portions including the first film portion and the second film portion; after forming the first pair of film portions, operating the drive roll to feed the continuous elastic film onto the vacuum drum at a second feed rate lower than the first feed rate; The method according to claim 1, further comprising the above steps.

3. operating the drive roll to feed the continuous elastic film onto the vacuum drum at the second feed rate for a predetermined time or for a predetermined length of the continuous elastic film; after the predetermined time has elapsed or after the predetermined length of the continuous elastic film has been fed, operating the drive roll to feed the continuous elastic film onto the vacuum drum at the first feed rate; While the continuous elastic film is being fed at the first feed rate, cutting the continuous elastic film with the cutting unit to form a second film portion pair including another first film portion of the series of individual first film portions and another second film portion of the series of individual second film portions; The method according to claim 2, further comprising.

4. Transferring the another first film portion from the vacuum drum to the third pair of arms of the stretching unit; Transferring the another second film portion from the vacuum drum to the fourth pair of arms of the stretching unit; Stretching the another first film portion in the CD by separating the third pair of arms in the CD when the stretching unit rotates from the pickup position to the transfer position; Stretching the another second film portion in the CD by separating the fourth pair of arms in the CD when the stretching unit rotates from the pickup position to the transfer position; The method according to claim 3, further comprising transferring the stretched another first film portion and another second film portion from the stretching unit to the support web.

5. When transferring the stretched first film portion and second film portion, and when transferring the stretched another first film portion and another second film portion, the method includes separating the stretched first film portion and second film portion of the first film portion pair by a first distance on the support web in the MD; and separating the stretched another first film portion and another second film portion of the second film portion pair by the first distance on the support web in the MD. The method according to claim 4.

6. When transferring the stretched first film portion and second film portion, and when transferring the stretched another first film portion and another second film portion, the method includes separating the first film portion pair on the support web from the second film portion pair by a second distance longer than the first distance in the MD. The method according to claim 5.

7. Transferring the first film portion and second film portion, and transferring the another first film portion and another second film portion from the vacuum drum are Rotating the extension unit to bring the first pair of arms and the second pair of arms adjacent to the vacuum drum to remove the first film portion and the second film portion from the vacuum drum; The method according to claim 4, further comprising rotating the extension unit to bring the third pair of arms and the fourth pair of arms adjacent to the vacuum drum to remove the other first film portion and the other second film portion from the vacuum drum.

8. The method according to claim 7, wherein the extension unit rotates at a constant speed.

9. The method according to claim 3, further comprising the step of selectively feeding the continuous elastic film onto the vacuum drum at the first feed rate or the second feed rate by supplying a rotational force to the drive roll via a servo motor.

10. The cutting unit includes a rotating cutting wheel, and the rotating cutting wheel has a first cutting element and a second cutting element fixedly arranged on the upper part so as to be close to each other on the rotating cutting wheel. The operation of the cutting unit includes: Performing a pair of cuts with the first cutting element and the second cutting element to form the first film portion and the second film portion; Rotating the rotating cutting wheel once; The method according to claim 3, further comprising performing another pair of cuts with the first cutting element and the second cutting element to form the other first film portion and the other second film portion.

11. The method according to claim 1, further comprising the step of rotating the vacuum drum at a drum speed higher than the first feed rate and the second feed rate at which the continuous elastic film is fed onto the vacuum drum so that the leading edge of the continuous elastic film slides across the surface of the vacuum drum when the continuous elastic film is fed onto the vacuum drum.

12. An apparatus for attaching an extended elastic segment to a support web, the apparatus comprising: A drive roll configured to feed a continuous elastic film in the machine direction (MD); A vacuum drum arranged to receive the continuous elastic film from the drive roll; A cutting unit arranged adjacent to the vacuum drum and configured to cut the continuous elastic film to produce a series of individual first film portions and individual second film portions; an extension unit configured to transfer the series of individual first film portions and the individual second film portions from the pickup position of the vacuum drum to the transfer position on the support web, the extension unit comprising: a first pair of arms configured to transfer the first film portion of the series of individual first film portions from the vacuum drum, the first pair of arms being separable in the lateral direction (CD); a second pair of arms configured to transfer the second film portion of the series of individual second film portions from the vacuum drum, the second pair of arms being separable in the CD; the first pair of arms and the second pair of arms each extend the first film portion and the second film portion in the CD by separating outwardly in the CD when moving from the pickup position to the transfer position; The driving roll is an apparatus operable to variably feed the continuous elastic film onto the vacuum drum at a first feed rate and a second feed rate slower than the first feed rate.

13. a servo motor configured to selectively drive the driving roll to feed the continuous elastic film onto the vacuum drum at one of the first feed rate and the second feed rate; The apparatus according to claim 12, further comprising a controller operably connected to the servo motor to control the operation of the servo motor.

14. The controller is configured to: operate the servo motor to feed the continuous elastic film onto the vacuum drum at the first feed rate for either a first predetermined period or a first predetermined length of the continuous elastic film with respect to the driving roll; operate the servo motor to feed the continuous elastic film onto the vacuum drum at the second feed rate for either a second predetermined period or a second predetermined length of the continuous elastic film with respect to the driving roll; The apparatus according to claim 13, wherein the servo motor can be operated to alternately feed the continuous elastic film on the vacuum drum at the first and second feed rates during the ongoing operation with respect to the driving roll.

15. The cutting unit comprises: a rotary cutting wheel including a first cutting element and a second cutting element attached to the rotary cutting wheel, The apparatus according to claim 14, wherein the first cutting element and the second cutting element are disposed close to each other on one side of the rotary cutting wheel.

16. The controller positions the first and second cutting elements to cut the continuous elastic film while or immediately before the feed rate transitions from the first feed rate to the second feed rate, and further, while the feed rate is the second feed rate, the rotation of the rotary cutting wheel is adjusted by the operation of the servo motor such that the first and second cutting elements rotate through a non-cutting range. The apparatus according to claim 15.

17. The extension unit, a third pair of arms configured to pick up another first film portion of the series of individual first film portions from the vacuum drum, the third pair of arms being separable within the CD machine, a fourth pair of arms configured to pick up another second film portion of the series of individual second film portions from the vacuum drum, the fourth pair of arms being separable within the CD machine, and further including The apparatus according to claim 12, wherein the third pair of arms and the fourth pair of arms each separate outwardly in the CD direction when moving from the pickup position to the transfer position, so that the another first film portion and the another second film portion each extend in the CD direction.

18. The apparatus according to claim 17, wherein the first pair of arms and the second pair of arms are disposed close to each other, the third pair of arms and the fourth pair of arms are disposed close to each other, and the third pair of arms and the fourth pair of arms are disposed on the opposite side of the extension unit from the first pair of arms and the second pair of arms.

19. A method of attaching individual stretched film portions to a support web, comprising: operating a drive roll to feed a continuous elastic film longitudinally (MD) onto a vacuum drum; operating a cutting unit to form a series of individual first film portions and individual second film portions from the continuous elastic film; operating an extension unit including a plurality of pairs of arms, Transfer the series of individual first film portions and individual second film portions rotatably from the pickup position of the vacuum drum to the transfer position on the support web, and each pair of arms of the plurality of pairs of arms fixes the respective first film portion or second film portion. By separating each pair of arms of the plurality of pairs of arms in the lateral direction (CD) between the pickup position and the transfer position, each of the first film portions and the second film portions is extended in the CD. A step of depositing the series of individual first film portions and individual second film portions on the support web at the transfer position. Including The first film portion and the second film portion of the first film portion pair deposited on the support web are separated by a first distance in the MD. A method in which a second film portion pair including another first film portion and another second film portion deposited on the support web is separated by a second distance longer than the first distance from the first film portion pair in the MD.

20. A step of operating the drive roll to feed the continuous elastic film onto the vacuum drum at the first feed rate. While the continuous elastic film is being fed at the first feed rate, cutting the continuous elastic film with the cutting unit to form the first film portion pair. After forming the first film portion pair, operating the drive roll to feed the continuous elastic film onto the vacuum drum at a second feed rate lower than the first feed rate. Operating the drive roll to feed the continuous elastic film onto the vacuum drum again at the first feed rate. While the continuous elastic film is being fed at the first feed rate, cutting the continuous elastic film with the cutting unit to form the second film portion pair. The method according to claim 19, further comprising.

21. A step of operating the plurality of pairs of arms that rotatably transfer and extend the first film portion and the second film portion of the first film portion pair, and operating the first pair of arms and the second pair of arms from the plurality of pairs of arms. The method according to claim 19, further comprising: operating a third pair of arms and a fourth pair of arms from the plurality of pairs of arms, the plurality of pairs of arms rotatably transferring and extending the other first film portion and the other second film portion of the second film portion pair.

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