An apparatus and method for application of discrete parts

Abstract

An apparatus for applying discrete parts to a moving web includes a rotor rotatable about an axis and a carrier coupled to the rotor. The carrier includes a casing and an applicator. The casing defines an interior connectable to a vacuum source and a positive pressure source. The applicator includes a plurality of apertures in fluid communication with the interior of the casing. The applicator is configured for engaging a discrete part on a support surface of the applicator when the vacuum source draws fluid from the interior of the casing. The applicator is configured for disengaging the discrete part on the support surface when the positive pressure source urges fluid into the interior of the casing. The applicator also includes features for blocking fluid flow through a set of the plurality of apertures when the positive pressure source urges the fluid into the interior of the casing.

Description

BACKGROUND Manufacture of absorbent articles, such as disposable diapers or incontinence inserts, can include applying discrete parts or components, absorbent materials, leg elastics, waist elastics, tapes, and other fasteners, to a continuously moving web. Moreover, adding the various absorbent article parts during manufacture of the absorbent article can include sequentially feeding the parts onto the continuously moving web. However, the speed at which the parts are fed into the process is frequently not the same as the speed of the product web itself is traveling. To transfer discrete parts onto a moving web, certain transfer assemblies include a puck that uses vacuum to engage the discrete parts onto the puck and blow-off to disengage the discrete parts from the puck onto the moving web. The vacuum and blow-off are both applied at the same holes on a surface of the puck. This can pose challenges with disengaging absorbent cores with relatively high amounts of fluff and / or superabsorbent material. Moreover, the blow-off can generate defects in such absorbent cores. Accordingly, an apparatus for applying discrete parts to a moving web that includes features for facilitating disengagement of the discrete parts would be useful. Moreover, an apparatus for applying discrete parts to a moving web that reduces defects during disengagement of the discrete parts would be useful. SUMMARY In general, the present disclosure is directed to an apparatus for applying discrete parts to a moving web. The apparatus includes a carrier that differentially applies vacuum and blow-off at apertures of an applicator. For instance, the vacuum may be applied around an entire perimeter of the applicator. Conversely, the blow-off may be blocked or limited at a trailing edge portion of the applicator to limit or prevent defects, which can be caused by the blow-off, as a discrete part transfers from the applicator to the moving web. Relative to allowing application of both vacuum and blow-off at all apertures of the applicator, the carrier can selectively apply vacuum and blow-off at different zones on the applicator. Applying vacuum at all the apertures can advantageously assist with securely holding the discrete part on the carrier. Limiting the blow-off to a smaller zone on the applicator can advantageously assist with transferring the discrete part from the carrier to the moving web, e.g., by providing blow-off at a leading edge portion of the applicator while limiting or preventing quality defects in the discrete part by blocking blow-off at the trailing edge portion of the applicator. In one example embodiment, an apparatus for applying discrete parts to a moving web includes a rotor rotatable about an axis and a carrier coupled to the rotor. The carrier includes a casing and an applicator. The casing defines an interior connectable to a vacuum source and a positive pressure source. The applicator includes a plurality of apertures in fluid communication with the interior of the casing. The carrier further includes a check valve. The applicator is configured for engaging a discrete part on a support surface of the applicator when the vacuum source draws fluid from the interior of the casing. The applicator is configured for disengaging the discrete part on the support surface when the positive pressure source urges fluid into the interior of the casing. The check valve is configured to block fluid flow through a set of the plurality of apertures when the positive pressure source urges the fluid into the interior of the casing. In another example embodiment, a system for applying discrete parts to a moving web includes a vacuum source, a positive pressure source, and a transfer assembly. The transfer assembly includes a rotor rotatable about an axis and a carrier coupled to the rotor. The carrier includes a casing and an applicator. The casing defines an interior in fluid communication with the vacuum source and the positive pressure source. The applicator includes a plurality of apertures in fluid communication with the interior of the casing. The applicator is configured for engaging a discrete part on an outer surface of the applicator when the vacuum source draws fluid from the interior of the casing and through the plurality of apertures on an engaging region of the applicator. The applicator is configured for disengaging the discrete part on the outer surface when the positive pressure source urges fluid into the interior of the casing and through the plurality of apertures on a disengaging region of the applicator. A number of the plurality of apertures in the engaging region is greater than a number of the plurality of apertures in the disengaging region. In another example embodiment, a method for applying discrete parts to a moving web, includes: traversing a web along a machine direction; engaging a discrete part on an applicator of a carrier while the carrier is rotating and a vacuum source draws fluid from an interior of a casing of the carrier and through a plurality of apertures on an engaging region of the applicator; and disengaging the discrete part from the applicator onto the web while the carrier is rotating and a positive pressure source urges fluid into the interior of the casing and through the plurality of apertures on a disengaging region of the applicator. The engaging region is smaller than the disengaging region. These and other features, aspects and advantages of the present disclosure will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS A full and enabling disclosure of the present disclosure, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures. FIG. 1 is a partial, side elevation view of a transport apparatus according to an example embodiment. FIG. 2 is a side elevation view of the example transport apparatus of FIG. 1. FIG. 3 is an exploded perspective view of a discrete part according to an example embodiment. FIG. 4 is a top view of the example discrete part of FIG. 3. FIG. 5 illustrates a method of making an absorbent product according to an example embodiment and using the example discrete part of FIGS. 3 and 4. FIG. 6 is an isometric view of a transfer assembly according to an example embodiment of the present subject matter. FIG. 7 is a section view of the example transfer assembly of FIG. 6 with a vacuum source shown drawing fluid from an interior of an applicator and a check valve shown in an open configuration. FIG. 8 is a section view of the example transfer assembly of FIG. 6 with a positive pressure source shown urging fluid into the interior of the applicator and the check valve shown in a closed configuration. FIG. 9 is a flow chart of a method for applying a discrete part to a moving web according to an example embodiment of the present subject matter.. Repeat use of reference characters in the present specification and drawing is intended to represent the same or analogous features or elements of the present invention. DETAILED DESCRIPTION The present disclosure is generally directed to an apparatus for applying discrete parts to a moving web. The apparatus includes a carrier coupled to a rotor. The carrier includes a casing and an applicator. An interior of the casing is connectable to a vacuum source and a positive pressure source. The applicator includes a plurality of apertures in fluid communication with the interior of the casing. When the vacuum source draws fluid from the interior of the casing, the applicator engages a discrete part on a support surface of the applicator. Moreover, ambient air around the applicator may flow through the apertures into the interior of the casing when the vacuum source draws fluid from the interior of the casing. The air entering the apertures may engage and hold the discrete part on the support surface of the applicator. The applicator disengages the discrete part from the support surface when the positive pressure source urges fluid into the interior of the casing. Moreover, air within the interior of the casing may exit through the apertures out of the carrier when the positive pressure source urges fluid into the interior of the casing. The air exiting the apertures may disengage the discrete part from the support surface of the applicator onto a moving web. The vacuum source draws air through apertures on an engaging region of the applicator. Conversely, the positive pressure source urges air through the apertures on a disengaging region of the applicator. The disengaging region may be smaller than the engaging region. For example, a check valve may close and block / obstruct a set of the apertures when the positive pressure source urges fluid into the interior of the casing. Regulating the fluid flow through the apertures in such a manner may advantageously limit or prevent quality defects in the discrete part. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present disclosure. When introducing elements of the present disclosure or the preferred embodiment(s) thereof, the articles “a”, "an”, "the” and "said” are intended to mean that there are one or more of the elements. As used herein, the terms “includes” and “including” are intended to be inclusive in a manner similar to the term “comprising.” Similarly, the term “or” is generally intended to be inclusive (i.e., “A or B" is intended to mean “A or B or both”). Approximating language, as used herein throughout the specification and claims, is applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately,” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. For example, the approximating language may refer to being within a ten percent (10%) margin. Transport Apparatus: FIG. 1 is a partial side, elevation view of a transport apparatus 10 according to an example embodiment. As shown in FIG. 1, the transport apparatus 10 may include a transfer assembly 12 and a web conveyor 14. The transfer assembly 12 includes a rotor or support 16 attached at one end to a puck or carrier 20 and at the other end with a drive member 22, which is configured to move the transfer assembly 12 through a range of motion in a generally curvilinear path. As an example, the drive member 22 may be a conventional drive member for rotating the transfer assembly 12. The web conveyor 14 is configured to support and advance a substrate web 24. As shown in the illustrated example embodiment, the web conveyor 14 may be a rotary drum; however, in other example embodiments, the web conveyor 14 may be a roller, a linear conveyor, or other conveyers. The transport apparatus 10 may be configured to engage a discrete part 26, transport the discrete part 26 through the curvilinear path, and apply the discrete part 26 to the substrate web 24. The discrete parts 26 and the substrate web 24 may collectively form at least a portion of a product. The transport apparatus 10 may be used with many types of discrete parts that may be used for constructing a variety of products, as will become apparent from the description that follows. In example embodiments, the transport apparatus 10 may be used to form disposable absorbent articles, such as diapers, training pants, or incontinence inserts. The transport apparatus 10 may be configured in the manner described in U.S. Patent No. 7,341,087 of Tabor et al., which is incorporated by reference in its entirety herein. FIG. 2 is a front view of the transport apparatus 10 in accordance with example aspects of the present disclosure. In FIG. 2, the transport apparatus 10 includes five (5) transfer assemblies 12, which are configured to transport and apply discrete parts to a substrate web. It will be understood that the transport apparatus 10 may include any number of transfer assemblies 12 depending upon the different web speeds and desired placement and size of the discrete parts. The transport apparatus 10 may receive a first web 82 having a plurality of interconnected discrete parts 26 and traveling at a first speed in a machine direction 84 associated therewith. An adhesive 86 may be applied to a surface of the first web 82. The movement of the transfer assemblies 12 may sever or tear the first substrate web 82 along perforations (not shown) into discrete parts 26 and may apply the discrete parts 26 to a substrate web 88 supported by a web conveyor 90 and traveling at a second speed in the direction indicated by the arrow associated therewith. One or more vacuum sources (not shown) may be used to provide vacuum to apertures of the transfer assembly 12 and assist in the transport and transfer of the discrete parts 26 to the second web 88. Each transfer assembly 12 may be configured to be moved by a drive member 94 having a first axis 96 such that the surface speed of each transfer assembly 12 is substantially equal to the speed of the first substrate web 82 as the discrete parts 26 are received by the transfer assembly 12 and substantially equal to the speed of the second substrate web 88 as the discrete parts 26 are applied to the substrate web 88, as more fully explained below. Each transfer assembly 12 may be coaxially supported and rotatably connected to a common idler member 98 on a second axis 100. The transfer assemblies 12 may be configured to rotate about the second axis 100. Each transfer assembly 12 may include a support 16 which is rotatably connected to the idler member 98 such that each transfer assembly 12 can be rotated independently. The radial inner end of the support 16 of each transfer assembly 12 may be rotatably connected to the idler member 98 by any technique known to those skilled in the art such as, for example, using conventional bearings. Similarly, the other components of the transport apparatus 10 may be rotatably connected together employing such conventional techniques. The carrier 20 of each transfer assembly 12 may travel along and defines a common circumferential path that allows the discrete parts 26 to be received form the web 82 and applied to the second substrate web 88. Each carrier 20 may be configured to receive at least one discrete part 26 and apply the discrete part 26 to the second substrate web 88 during each revolution. The drive member 94 may be configured to move each transfer assembly 12 at a variable speed, but the drive member 94 itself may be configured to be rotated at a constant speed about the axis of the drive member 94 by a motor (not shown). The motor may be operatively connected through suitable gearing and drive belts to the drive member 94. Thus, in use, the motor may rotate the drive member 94, which, in turn, moves the transfer assemblies 12 at the desired variable speed. To provide the desired variable speed of each transfer assembly 12, the axis 96 of the drive member 94 is offset from the axis 100 of the idler member 98 and the transfer assemblies 12 by an offset distance. The offset distance between the first axis 96 and the second axis 100 may be any distance which provides the desired variations in the speed of the outer surface 46 of each transfer assembly 12. The transport apparatus 10 may further include at least one coupler arm 112, which has a first end portion 114 and a second end portion 116. The second end portion 116 is pivotally connected to the drive member 94 about a pivot point 118. The transport apparatus 10 may include one coupler arm 112 for each transfer assembly 12. Accordingly, in the transport apparatus 10 shown in FIG. 2, which includes five transfer assemblies 12, five coupler arms 112 independently connect the drive member 94 to each respective transfer assembly 12. The coupler arms 112 may be pivotally connected to the drive member 94 about pivot points 118, which are selectively located to provide the desired speeds for the transfer assemblies 12. In a particular example aspect, the pivot points 118 for the coupler arms 112 are located the same distance radially outward from the axis 96 of the drive member 94. In such a configuration, the pivot points 118 rotate at a constant speed along a common circumferential path as the drive member 94 is rotated at a constant speed. The coupler arms 112 may be pivotally connected to the drive member 94 by conventional mechanism known to those skilled in the art. The coupler arm 112 may be configured to follow a curvilinear path and is slidably connected to a respective transfer assembly 12. As the drive member 94 is rotated, the coupler arm 112 may be guided along the curvilinear path, and each coupler arm 112 may slidably engage the respective transfer assembly 12 thereby pivoting the coupler arm 112 about the pivot point 118. The pivoting of the coupler arm 112 and the offset crank motion of the drive member 94 vary the effective drive radius of each transfer assembly 12 and move each transfer assembly 12 at a variable speed. The second end portion 116 of each coupler arm 112 may be slidably connected to the respective transfer assembly 12 by any mechanism known to those skilled in the art, such as by a slide track 122. The use of the combination of the offset drive member 94 and pivoting coupler arm 112 to drive the transfer assemblies 12 in the apparatus 80 can provide an inexpensive and adaptable method for severing a first substrate web 82 traveling at a speed into discrete parts 26 and applying the discrete parts 26 to a substrate web 88 traveling at a different speed. The design of the drive member 94 and coupler arm 112 can be analytically determined to obtain the desired output function which can include variable angular velocities with fixed speed dwells. In example aspects, the surface speed of each transfer assembly 12 may be maintained substantially constant as the discrete parts 26 are received from the feed conveyor 124. The surface speed may be variable while the transfer assembly is rotated ninety degrees (90°) prior to the application of the discrete part unto the substrate web 88. The surface speed may be constant when the discrete part is applied to the substrate web 88. The apparatus and method described herein may be used in the manufacture of discrete parts, such as diapers, training pants, and adult incontinence products, among other uses. In particular, the apparatus and method may be used to apply discrete parts or components, such as, for example, absorbent layers, waist elastics, leg elastics, tapes, snaps, and hook and loop materials to the diaper or incontinence product. Discrete parts, such as diapers and incontinence products, are described, for example, in: U.S. Pat. Nos. 4,704,116 issued Nov. 3,1987; U.S. Pat. No. 4,798,603 issued Jan. 17, 1989; U.S. Pat. No. 4,710,187 issued Dec. 1,1987; U.S. Pat. No. 4,770,656 issued Sep. 13,1988; and U.S. Pat. No. 4,762,521 issued Aug. 9,1988, and U.S. Pat. No. 7,264,615 issued Sept. 4,2007; the disclosures of which are incorporated by reference in their entirety. Absorbent Article Formation Process: An example of a process for forming an absorbent product is shown representatively in FIGS. 3 through 5. As shown in FIG. 3, the discrete part 26 may be a multi-layered article that includes a fluid impermeable layer 30, a body-side liner 34, and an absorbent layer 36 sandwiched between the fluid impermeable layer 30 and the liner 34. The materials used to make such layers may be any of those conventional materials known in the art. Because the absorbent layer 36 has length L and width W that are smaller than the overall length L' and width W, respectively, of the discrete part 26, the area of the discrete part 26 having the absorbent layer 36 may define a portion 38 (FIG. 4) of the discrete part 26 that is thicker relative to the other portions 40 of the discrete part 26. Referring now to FIG. 5, the discrete part 26 may be placed upon an outward surface 42 of the substrate web 24 by the transfer assembly 12 (FIG. 1). Moreover, successive discrete parts 26 may be 7 sequentially placed onto the substrate web 24 as the web conveyor 14 advances the substrate web 24. In example embodiments, the substrate web may be a pair of webs; however, it will be understood that the substrate web 24 may be formed as a single web, or three, four, or more webs. Carrier: Turning now to FIG. 6, a carrier 200 according to an example embodiment of the present subject matter is shown, and FIGS. 7 and 8 are section views of the carrier 200. The carrier 200 may be used in or with any apparatus for applying discrete parts to a moving web. For instance, the carrier 200 may be used in the transport apparatus 10 (FIG. 1) as the carrier 20. Thus, carrier 200 is described in greater detail below in the context of the transport apparatus 10; however, it will be understood that the carrier 200 is not limited to use within the transport apparatus 10. As discussed in greater detail below, the carrier 200 includes features for assisting with transfer of a discrete part off the carrier 200, e.g., by regulating fluid flow through apertures. The carrier 200 includes a casing 210 and an applicator 220. The casing 210 may include a plurality of walls 211, such as a bottom wall and sidewalls. The casing 210 (e.g., walls 211) defines an interior 212 (FIGS. 7 and 8). The applicator 220 may be mounted to the casing 210 and assist with forming the interior 212 of the casing 210. For example, the applicator 220 may define a top of the interior 212 in certain example embodiments. The applicator 220 may also include a plurality of apertures 222. The apertures 222 may be in fluid communication with the interior 212 of the casing 210. For example, the apertures 222 may extend through the applicator 220, e.g., from an outer or support surface 224 of the applicator 220 to an inner surface 225 of the applicator 220. The inner surface 225 of the applicator 220 may face towards the interior 212 of the applicator 220, and the outer surface 224 of the applicator 220 may face away from the interior 212 of the applicator 220. Fluid, such as air, may flow through the apertures 222 into and out of the interior 212 of the casing 210. The outer surface 224 of the applicator 220 may be configured for supporting discrete parts 26. Moreover, as described in greater detail below, fluid flowing into the interior 212 of the casing 210 through the apertures 222 may assist with application of the discrete part 26 onto the outer surface 224 of the applicator 220 and / or with holding of the discrete part 26 on the outer surface 224 of the applicator 220. Conversely, fluid flowing out of the interior 212 of the casing 210 through the apertures 222 may assist with removal of the discrete part 26 from the outer surface 224 of the applicator 220. As shown in FIGS. 7 and 8, the interior 212 of the casing 210 is connectable to a vacuum source 250 and a positive pressure source 260. The vacuum source 250 may be any source of negative pressure relative to ambient air, such as a vacuum pump, an ejector, etc. When the interior 212 of the casing 210 is connected to the vacuum source 250, the pressure within the interior 212 of the casing 210 may be less than ambient air, and the vacuum source 250 may draw fluid out of the interior 212 of the casing 210, which is shown with arrow VO in FIG. 7. Moreover, the vacuum source 250 may also draw air into the interior 212 of the casing 210 through the apertures 222 when the interior 212 of the casing 210 is connected to the vacuum source 250, as shown with arrows Fl in FIG. 7. Thus, the negative pressure (relative to ambient) of the vacuum source 250 may assist with application of the discrete part 26 onto the outer surface 224 of the applicator 220 and / or with holding of the discrete part 26 on the outer surface 224 of the applicator 220 by drawing air through the apertures 222 into the interior 212 of the casing 210. The positive pressure source 260 may be any source of positive pressure relative to ambient air, such as a compressor, a pump, etc. When the interior 212 of the casing 210 is connected to the positive pressure source 260, the pressure within the interior 212 of the casing 210 may be greater than ambient air, and the positive pressure source 260 may urge fluid into the interior 212 of the casing 210, which is shown with arrow PI in FIG. 8. Moreover, the positive pressure source 260 may also urge air out of the interior 212 of the casing 210 through the apertures 222 when the interior 212 of the casing 210 is connected to the positive pressure source 260, as shown with arrows FO in FIG. 8. Thus, the positive pressure (relative to ambient) of the positive pressure source 260 may assist with removal of the discrete part 26 from the outer surface 224 of the applicator 220 by forcing air through the apertures 222 from the interior 212 of the casing 210. The applicator 220 may extend between a leading edge portion 245 and a trailing edge portion 246, e.g., along a transverse direction T. Thus, the leading edge portion 245 of the applicator 220 may be spaced from the trailing edge portion 246 of the applicator 220, e.g., along the transverse direction T. As the carrier 200 rotates towards the second substrate web 88, the discrete parts 26 on the carrier 200 may first contact the substrate web 88 at the leading edge portion 245 of the applicator 220. Conversely, as the carrier 200 rotates away from the second substrate web 88, the discrete parts 26 on the carrier 200 may last contact the carrier 200 at the trailing edge portion 245 of the applicator 220. A width of the applicator 220 along the transverse direction T, e.g., between the leading edge portion 245 and the trailing edge portion 246, may be selected to complement a width of the discrete part 26 on the carrier 200. For example, the width of the applicator 220 may be no less than seven centimeters (7 cm) and no greater than thirty centimeters (30 cm). The applicator 220 may also extend between a first side portion 247 and a second side portion 248, e.g., along a lateral direction L, which may be perpendicular to the transverse direction T. Thus, the first side portion 247 of the applicator 220 may be spaced from the second side portion 248 of the applicator 220, e.g., along the lateral direction L. As the carrier 200 rotates towards the first substrate web 82, the applicator 220 may first contact the first substrate web 82 at the first side portion 247 of the applicator 220. As the carrier 200 rotates away from the first substrate web 82, the applicator 220 may sever or tear the first substrate web 82 along perforations (not shown) at the second side portion 248 of the applicator 220 to form a discrete part 26 on the applicator 220. A length of the applicator 220 along the lateral direction L, e.g., between the first side portion 247 and the second side portion 248, may be selected to complement or correspond to a length of the discrete part 26 on the carrier 200. For example, the length of the applicator 220 may be no less than twenty-five centimeters (25 cm) and no greater than seventy-five centimeters (75 cm). In example embodiments, the apertures 222 may be distributed along a perimeter of the applicator 220. For instance: a first set of the apertures 222 may be disposed at the leading edge portion 245 of the applicator 220 and may be distributed along the transverse direction T between the first and second side portions 247, 248 of the applicator 220; a second set of the apertures 222 may be disposed at the trailing edge portion 246 of the applicator 220 and may be distributed along the transverse direction T between the first and second side portions 247, 248 of the applicator 220; a third set of the apertures 222 may be disposed at the first side portion 247 of the applicator 220 and may be distributed along the transverse direction T between the leading and trailing edge portions 245, 246 of the applicator 220; and a fourth set of the apertures 222 may be disposed at the second side portion 248 of the applicator 220 and may be distributed along the transverse direction T between the leading and trailing edge portions 245, 246 of the applicator 220. Apertures 222 may be disposed at or adjacent each edge of the applicator 220 in certain example embodiments. Thus, e.g., when the applicator 220 has a quadrilateral shape, subsets of the apertures 222 may be positioned at or adjacent each of the four edges of the applicator 220. Such distributions of the apertures 222 may advantageously assist with holding the discrete part 26 on the applicator 220. In certain example embodiments, the applicator 220 may include one, two, three or more rows of apertures 222 at the leading edge portion 245 of the applicator 220, with each of the row(s) including no less that twenty (20), twenty-five (25), thirty (30) or more apertures 222 and / or no greater than one hundred (100) apertures 222. The applicator 220 may also include one, two, three or more rows of apertures 222 at the trailing edge portion 246 of the applicator 220, with each of the row(s) including no less that twenty (20), twenty-five (25), thirty (30) or more apertures 222 and / or no greater than one hundred (100) apertures 222. In certain example embodiments, the applicator 220 may include one, two, or more columns of apertures 222 at the first side portion 247 of the applicator 220, with each of the column(s) including no less that ten (10), fifteen (15), twenty (20), twenty-five (25), thirty (30) or more apertures 222 and / or no greater than seventy-five (75) apertures 222. The applicator 220 may also include one, two, or more columns of apertures 222 at the second side portion 248 of the applicator 220, with each of the column(s) including no less that ten (10), fifteen (15), twenty (20), twenty-five (25), thirty (30) or more apertures 222 and / or no greater than seventy-five (75) apertures 222. As noted above, the carrier 200 includes features for assisting with transfer of a discrete part, such as discrete part 26, off the carrier 200, e.g., by regulating fluid flow through apertures 222. Moreover, as shown in FIG. 7, the applicator 220 may be configured for engaging a discrete part 202 on the outer surface 224 of the applicator 220 when the vacuum source 250 draws fluid VO from the interior 212 of the casing 210 and through the apertures 222 on an engaging region 240 of the applicator 220, shown with arrows Fl. With reference now to FIG. 8, the applicator 220 is also configured for disengaging the discrete part 202 on the outer surface 224 of the applicator 220 when the positive pressure source 260 urges fluid PI into the interior 212 of the casing 210 and through the apertures 222 on a disengaging region 242 of the applicator 220. As shown in FIGS. 7 and 8, a number of apertures 222 in the engaging region 240 (FIG. 7) is greater than a number of apertures 222 in the disengaging region 242 (FIG. 8). In example embodiments, the number of apertures 222 at the disengaging region 242 may correspond to no less than five percent (5%) and no greater than forty percent (40%) of the number of apertures 222 at the engaging region 240. The engaging region 240 may be larger than the disengaging region 242 on the applicator 220. In certain example embodiments, the apertures 222 in the engaging region 240 may correspond to all or substantially all of the apertures 222 that extend through the applicator 220 for fluid communication between the interior 212 of the casing 210 and ambient air about the carrier 200. Conversely, the apertures 222 in the disengaging region 242 may correspond to a set or portion of the apertures 222 that extend through the applicator 220 for fluid communication between the interior 212 of the casing 210 and ambient air about the carrier 200. Thus, e.g., the set or portion 244 of the apertures 222 may be blocked, obstructed, or otherwise limited with regards to fluid flow when the positive pressure source 260 urges fluid PI into the interior 212 of the casing 210. Regulating fluid flow through the apertures 222 may have various benefits. For instance, vacuum pressure may be provided across all apertures in the carrier 200 to assist with holding the discrete part 202 on the outer surface 224 of the applicator 220, and the positive pressure may be limited or blocked at some of the apertures in the carrier 200 during transfer in order to have a more controlled transfer of the discrete part 202 off the outer surface 224 of the applicator 220. Such fluid flow regulation may advantageously limit or prevent quality defects in the discrete part 202, e.g., which can be caused by blow-off applied to the discrete part 202 at the trailing edge portion 246 of the applicator 220. Moreover, such fluid flow regulation may advantageously limit or prevent quality defects in the discrete part 202, e.g., which include relatively high amounts of fluff and / or superabsorbent material in the absorbent layer 36 that can make the absorbent layer 36 fragile and difficult to transfer without defect. The fluid flow through apertures 222 may be regulated in various manners. For example, as shown in FIGS. 7 and 8, the carrier 200 may also include a check valve 230. The check valve 230 may be configured for regulating fluid flow through a set of the apertures 222. For instance, the check valve 230 may be configured for blocking fluid flow through the set of the plurality of apertures 222 when the positive pressure source 260 urges the fluid into the interior 212 of the casing 210. Thus, e.g., the check valve 230 may close in order to block or limit fluid flow out of the interior 212 of the casing 210 through the set of the plurality of apertures 222 when the positive pressure source 260 urges the fluid into the interior 212 of the casing 210. Conversely, the check valve 230 may open in order to permit fluid flow into the interior 212 of the casing 210 through the set of the plurality of apertures 222 when the vacuum source 250 urges the fluid out of the interior 212 of the casing 210. It will be understood that the applicator 220 may include two, three, or more check valves 230 in example embodiments and depending upon the desired arrangement of the carrier 200. The check valve 230 may be disposed within the interior 212 of the casing 210 and may be mounted to the applicator 220, e.g., at the inner surface 225 of the applicator 220. In certain example embodiments, the check valve 230 may include a reed petal or plate 232. The reed plate 232 may be moveable between a closed position (FIG. 8) and an open position (FIG. 7). For instance, the reed plate 232 may be mounted to the applicator 220, e.g., the inner surface 225 of the applicator 220, at a proximal end portion 234 of the reed plate 232, and a distal end portion 236 of the reed plate 232 may project into the interior 212 of the casing 210. Thus, the reed plate 232 may be cantilevered on the applicator 220 such that the reed plate 232 is moveable between the closed position and the open position by deflection of the distal end portion 236 of the reed plate 232 relative to the apertures. In example embodiments, the reed plate 232 may be formed from an elastically deformable material, such as plastic shim stock, spring steel, carbon fiber, fiberglass, etc. In example embodiments, the check valve 230 may also include a stop plate, e.g., mounted on the applicator 220 at the inner surface 225 of the applicator 220. The reed plate 232 may be positioned over the set of apertures 222 in order to block the fluid flow through the set of apertures 222 when the positive pressure source 260 urges the fluid PI into the interior 212 of the casing 210. Moreover, the distal end portion 236 of the reed plate 232 may be positioned at or against the inner surface 225 of the applicator 220 below the set of apertures 222 in order to block the fluid flow through the set of apertures 222 when the positive pressure source 260 urges the fluid PI into the interior 212 of the casing 210. Conversely, the reed plate 232 may be positioned away from the set of apertures 222 when the vacuum source 250 draws the fluid VO from the interior 212 of the casing 210. Moreover, the distal end portion 236 of the reed plate 232 may be positioned away from the inner surface 225 of the applicator 220 below the set of apertures 222 in order to allow the fluid flow Fl through the set of apertures 222 when the vacuum source 250 urges the fluid VO out of the interior 212 of the casing 210. As may be seen from the above, the carrier 200 may differentially apply vacuum and blow-off on the applicator 220 via the apertures 222. Thus, rather than only allowing application of both vacuum and blow-off at the same locations, the carrier 200 can selectively apply vacuum and blow-off at different zones on the applicator 220. For example, the carrier 200 can apply vacuum at all the apertures 222 while limiting blow-off to a set of the apertures 222 on the applicator 220 (e.g., rather than all of the apertures 222). Applying vacuum at all the apertures 222 can advantageously assist with securely holding the discrete part 202 on the carrier 200. Limiting the blow-off to the set of the apertures 222 on the applicator 220 can advantageously assist with transferring the discrete part 202 from the carrier 200 to the web conveyor 90 by providing blow-off at the leading edge portion 245 of the applicator 220 while limiting or preventing quality defects in the discrete part 202 by blocking blowoff at the trailing edge portion 246 of the applicator 220. Discrete Part Application Method: FIG. 9 illustrates a method 900 for applying discrete parts to a moving web according to an example embodiment of the present subject matter. Method 900 is described in greater detail below in the context of the transport apparatus 10 and the carrier 200. However, it will be understood that method 900 may be used in or with other transfer apparatus for a discrete part to a moving web. At 910, a web may traverse along a machine direction. For example, the web conveyor 90 may traverse the substrate web 88 at 910. At 920, a discrete part may be engaged on an applicator of a carrier, e.g., while the carrier is rotating and a vacuum source draws fluid from an interior of a casing of the carrier. For example, the transport apparatus 10 may rotate to engage the first web 82 and thereby sever or tear the first substrate web 82 along perforations (not shown) into discrete parts 26 via the carrier 200. Thus, e.g., at 920, the applicator 220 may engage one of the discrete parts 26, such as discrete part 202, on the outer surface 224 of the applicator 220. The vacuum source 250 may draw the fluid VO from the interior 212 of the casing 210 and through the apertures 222 on the engaging region 240 of the applicator 220 in order to engage and hold the discrete part 26 on the applicator 220 via the vacuum through apertures 222 at the engaging region 240. The check valve 230 may be open at 920. At 930, the discrete part may be disengaged from the applicator of the carrier, e.g., while the carrier is rotating and a positive pressure source urges fluid into the interior of the casing of the carrier. For example, the transport apparatus 10 may continue to rotate to move the discrete part 26 towards the substrate web 88 on the web conveyor 90. Thus, e.g., at 930, the applicator 220 may disengage the one of the discrete parts 26, such as discrete part 202, from the outer surface 224 of the applicator 220 onto the substrate web 88 on the web conveyor 90. The positive pressure source 260 may urge the fluid PI into the interior 212 of the casing 210 and through the apertures 222 on the disengaging region 242 of the applicator 220 in order to disengage and remove the discrete part 26 from the applicator 220 onto the substrate web 88 via the blow-off through apertures 222 at the disengaging region 242. The check valve 230 may be closed at 930, e.g., such that blow-off at a set 244 (FIG. 8) of the apertures 222, which may be located at the trailing edge portion 246 of the applicator 220, is blocked or prevented. FIG. 9 depicts steps performed in a particular order for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that the steps of any of the methods discussed herein may be adapted, rearranged, expanded, omitted, or modified in various ways without deviating from the scope of the present disclosure. Moreover, although aspects of method 900 are explained using the transport apparatus 10 and carrier 200 as an example, it should be appreciated that these methods may be applied to the operation of any transfer apparatus for a discrete part to a moving web. These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention so further described in such appended claims. EXAMPLE EMBODIMENTS First example embodiment: An apparatus for applying discrete parts to a moving web, comprising: a rotor rotatable about an axis; and a carrier coupled to the rotor, the carrier comprising a casing and an applicator, the casing defining an interior connectable to a vacuum source and a positive pressure source, the applicator comprising a plurality of apertures in fluid communication with the interior of the casing, the carrier further comprising a check valve, wherein the applicator is configured for engaging a discrete part on a support surface of the applicator when the vacuum source draws fluid from the interior of the casing, wherein the applicator is configured for disengaging the discrete part on the support surface when the positive pressure source urges fluid into the interior of the casing, and wherein the check valve is configured to block fluid flow through a set of the plurality of apertures when the positive pressure source urges the fluid into the interior of the casing. Second example embodiment: The apparatus of the first example embodiment, wherein the check valve is configured for opening when the vacuum source draws the fluid from the interior of the casing. Third example embodiment: The apparatus of the first or the second example embodiment, wherein the check valve is disposed within the interior of the casing and is mounted to the applicator. Fourth example embodiment: The apparatus of any one of the first through third example embodiments, wherein the check valve comprises a reed plate, the reed plate moveable between a closed position and an open position, the reed plate positioned over the set of the plurality of apertures in order to block the fluid flow through the set of the plurality of apertures when the positive pressure source urges the fluid into the interior of the casing, the reed plate positioned away from the set of the plurality of apertures when the vacuum source draws the fluid from the interior of the casing. Fifth example embodiment: The apparatus of any one of the first through fourth example embodiments, wherein the plurality of apertures are distributed around a perimeter of the applicator. Sixth example embodiment: The apparatus of any one of the first through fifth example embodiments, wherein the set of the plurality of apertures are disposed at a trailing edge portion of the applicator. Seventh example embodiment: The apparatus of any one of the first through sixth example embodiments, wherein the set of the plurality of apertures comprises no less than two percent of the plurality of apertures and no greater than thirty percent of the plurality of apertures. Eighth example embodiment: A system for applying discrete parts to a moving web, comprising: a vacuum source; a positive pressure source; a transfer assembly comprising a rotor rotatable about an axis and a carrier coupled to the rotor, the carrier comprising a casing and an applicator, the casing defining an interior in fluid communication with the vacuum source and the positive pressure source, the applicator comprising a plurality of apertures in fluid communication with the interior of the casing, wherein the applicator is configured for engaging a discrete part on an outer surface of the applicator when the vacuum source draws fluid from the interior of the casing and through the plurality of apertures on an engaging region of the applicator, wherein the applicator is configured for disengaging the discrete part on the outer surface when the positive pressure source urges fluid into the interior of the casing and through the plurality of apertures on a disengaging region of the applicator, and a number of the plurality of apertures in the engaging region is greater than a number of the plurality of apertures in the disengaging region Nineth example embodiment: The system of the eighth example embodiment, further comprising a check valve configured for opening when the vacuum source draws the fluid from the interior of the casing and for closing when the positive pressure source urges fluid into the interior of the casing. Tenth example embodiment: The system of the eighth embodiment or the nineth example embodiment, wherein the check valve is disposed within the interior of the casing and is mounted to the applicator. Eleventh example embodiment: The system of any one of the eighth through tenth example embodiments, wherein the check valve comprises a reed plate, the reed plate moveable between a closed position and an open position, the reed plate positioned over the plurality of apertures on the disengaging region of the applicator in order to block the fluid flow through the plurality of apertures on the disengaging region when the positive pressure source urges the fluid into the interior of the casing, the reed plate positioned away from the plurality of apertures on the disengaging region of the applicator when the vacuum source draws the fluid from the interior of the casing. Twelfth example embodiment: The system of any one of the eighth through eleventh example embodiments, wherein the plurality of apertures are distributed around a perimeter of the applicator. Thirteenth example embodiment: The system of any one of the eighth through twelfth example embodiments, wherein the plurality of apertures in the disengaging region are disposed at a trailing edge portion of the applicator. Fourteenth example embodiment: The system of any one of the eighth through thirteenth example embodiments, wherein the plurality of apertures in the engaging region comprises all of the plurality of apertures, and the plurality of apertures in the disengaging region comprises a subset of the plurality of apertures. Fifteenth example embodiment: A method for applying discrete parts to a moving web, comprising: traversing a web along a machine direction; engaging a discrete part on an applicator of a carrier while the carrier is rotating and a vacuum source draws fluid from an interior of a casing of the carrier and through a plurality of apertures on an engaging region of the applicator; and disengaging the discrete part from the applicator onto the web while the carrier is rotating and a positive pressure source urges fluid into the interior of the casing and through the plurality of apertures on a disengaging region of the applicator, wherein the engaging region is smaller than the disengaging region. Sixteenth example embodiment: The method of the fifteenth example embodiment, wherein a check valve of the carrier is open when the vacuum source draws fluid from the interior of the casing, and the check valve of the carrier is closed when the positive pressure source urges fluid into the interior of the casing. Seventeenth example embodiment: The method of the fifteenth example embodiment or the sixteenth example embodiment, wherein the check valve comprises a reed plate, the reed plate positioned over a portion of the plurality of apertures. Eighteenth example embodiment: The method of any one of the fifteenth through seventeenth example embodiments, wherein the plurality of apertures in the engaging region are distributed around a perimeter of the applicator. Nineteenth example embodiment: The method of any one of the fifteenth through eighteenth example embodiments, wherein the plurality of apertures in the disengaging region are disposed at a trailing edge portion of the applicator.

Claims

What Is Claimed:

1. An apparatus for applying discrete parts to a moving web, comprising: a rotor rotatable about an axis; anda carrier coupled to the rotor, the carrier comprising a casing and an applicator, the casing defining an interior connectable to a vacuum source and a positive pressure source, the applicator comprising a plurality of apertures in fluid communication with the interior of the casing, the carrier further comprising a check valve,wherein the applicator is configured for engaging a discrete part on a support surface of the applicator when the vacuum source draws fluid from the interior of the casing,wherein the applicator is configured for disengaging the discrete part on the support surface when the positive pressure source urges fluid into the interior of the casing, andwherein the check valve is configured to block fluid flow through a set of the plurality of apertures when the positive pressure source urges the fluid into the interior of the casing.

2. The apparatus of claim 1, wherein the check valve is configured for opening when the vacuum source draws the fluid from the interior of the casing.

3. The apparatus of claim 1, wherein the check valve is disposed within the interior of the casing and is mounted to the applicator.

4. The apparatus of claim 3, wherein the check valve comprises a reed plate, the reed plate moveable between a closed position and an open position, the reed plate positioned over the set of the plurality of apertures in order to block fluid flow through the set of the plurality of apertures when the positive pressure source urges the fluid into the interior of the casing, the reed plate positioned away from the set of the plurality of apertures when the vacuum source draws the fluid from the interior of the casing.

5. The apparatus of claim 1, wherein the plurality of apertures are distributed around a perimeter of the applicator.

6. The apparatus of claim 1, wherein the set of the plurality of apertures are disposed at a trailing edge portion of the applicator.

7. The apparatus of claim 1, wherein the set of the plurality of apertures comprises no less than two percent of the plurality of apertures and no greater than thirty percent of the plurality of apertures.

8. A system for applying discrete parts to a moving web, comprising:a vacuum source;a positive pressure source; anda transfer assembly comprising a rotor rotatable about an axis and a carrier coupled to the rotor, the carrier comprising a casing and an applicator, the casing defining an interior in fluid communication with the vacuum source and the positive pressure source, the applicator comprising a plurality of apertures in fluid communication with the interior of the casing,wherein the applicator is configured for engaging a discrete part on an outer surface of the applicator when the vacuum source draws fluid from the interior of the casing and through the plurality of apertures on an engaging region of the applicator,wherein the applicator is configured for disengaging the discrete part on the outer surface when the positive pressure source urges fluid into the interior of the casing and through the plurality of apertures on a disengaging region of the applicator, anda number of the plurality of apertures in the engaging region is greater than a number of the plurality of apertures in the disengaging region.

9. The system of claim 8, further comprising a check valve configured for opening when the vacuum source draws the fluid from the interior of the casing and for closing when the positive pressure source urges fluid into the interior of the casing.

10. The system of claim 9, wherein the check valve is disposed within the interior of the casing and is mounted to the applicator.

11. The system of claim 10, wherein the check valve comprises a reed plate, the reed plate moveable between a closed position and an open position, the reed plate positioned over the plurality of apertures on the disengaging region of the applicator in order to block the fluid flow through the plurality of apertures on the disengaging region when the positive pressure source urges the fluid into the interior of the casing, the reed plate positioned away from the plurality of apertures on the disengaging region of the applicator when the vacuum source draws the fluid from the interior of the casing.

12. The system of claim 8, wherein the plurality of apertures are distributed around a perimeter of the applicator.

13. The system of claim 8, wherein the plurality of apertures in the disengaging region are disposed at a trailing edge portion of the applicator.

14. The system of claim 8, wherein the plurality of apertures in the engaging region comprises all of the plurality of apertures, and the plurality of apertures in the disengaging region comprises a subset of the plurality of apertures.

15. A method for applying discrete parts to a moving web, comprising:traversing a web along a machine direction;engaging a discrete part on an applicator of a carrier while the carrier is rotating and a vacuum source draws fluid from an interior of a casing of the carrier and through a plurality of apertures on an engaging region of the applicator; anddisengaging the discrete part from the applicator onto the web while the carrier is rotating and a positive pressure source urges fluid into the interior of the casing and through the plurality of apertures on a disengaging region of the applicator,wherein the engaging region is smaller than the disengaging region.

16. The method of claim 15, wherein a check valve of the carrier is open when the vacuum source draws fluid from the interior of the casing, and the check valve of the carrier is closed when the positive pressure source urges fluid into the interior of the casing.

17. The method of claim 16, wherein the check valve comprises a reed plate, the reed plate positioned over a portion of the plurality of apertures.

18. The method of claim 15, wherein the plurality of apertures in the engaging region are distributed around a perimeter of the applicator.

19. The method of claim 15, wherein the plurality of apertures in the disengaging region are disposed at a trailing edge portion of the applicator.

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