Apparatus and method for applying parallel flared elastics to disposable products and disposable products containing parallel flared elastics
11639282 ยท 2023-05-02
Assignee
Inventors
- Jeffrey W. Fritz (Plymouth, WI, US)
- Christopher J. NELSON (Plymouth, WI, US)
- John A. McCabe (Sheboygan Falls, WI, US)
- Daniel A. Peterson (Sheboygan, WI, US)
Cpc classification
A61F13/15601
HUMAN NECESSITIES
B65H63/024
PERFORMING OPERATIONS; TRANSPORTING
A61F13/15593
HUMAN NECESSITIES
A61F13/49017
HUMAN NECESSITIES
B65H57/14
PERFORMING OPERATIONS; TRANSPORTING
A61F13/49019
HUMAN NECESSITIES
B65H2701/194
PERFORMING OPERATIONS; TRANSPORTING
International classification
B65H57/14
PERFORMING OPERATIONS; TRANSPORTING
A61F13/15
HUMAN NECESSITIES
A61F13/49
HUMAN NECESSITIES
B65H35/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
An apparatus for applying elastics to a running web including a crank and arm, the arm arranged to reciprocate from side to side during use and having a laydown carriage carried on the arm, the laydown carriage including at least one eyelet arranged to support an elastic strand, the assembly further including a shoe guide.
Claims
1. A method for applying parallel flared elastics to a web comprising: providing a running web along a machine direction; providing a plurality of elastic threads to a reciprocation assembly, the reciprocation assembly comprising: a crank; a laydown carriage comprising a plurality of carriage strand guides; an arm coupled to the crank and to the laydown carriage; and a shoe guide assembly comprising a plurality of shoe strand guides spaced apart from each other at a variable spacing; reciprocating movement of the laydown carriage along a reciprocation axis via rotation of the crank about a crank rotation axis; and applying the plurality of elastic threads to the running web according to a pattern corresponding to an engagement of the plurality of elastic threads with the reciprocating movement of the laydown carriage and with the shoe guide assembly, wherein the spacing between the shoe strand guides is varied to influence the laydown of the elastic strands so that a distance between successive strands of the elastic threads is varied.
2. The method of claim 1 wherein the pattern is sinusoidal.
3. The method of claim 1 wherein the pattern comprises: a first region of each of the plurality of elastic strands running in parallel to one another, the elastic strands separated from each other in the machine direction by a first distance within the first region; a second region of each of the elastic strands running continuously away from the first region along a unique angle; a third region of the plurality of elastic strands running in parallel to one another, separated by a second distance in the machine direction, wherein the second distance is larger than the first distance.
4. The method of claim 1 wherein the shoe guide assembly further comprises a pair of shoe guide members spaced apart from each other along the reciprocation axis, each shoe guide member comprising a respective portion of the shoe strand guides.
5. The method of claim 4 further comprising: causing a first elastic strand of the plurality of elastic strands to slidingly engage one of the shoe strand guides of one of the shoe guide members of the pair of shoe guide members when the laydown carriage is positioned in a first end reciprocation location along the reciprocation axis; and positioning the first elastic strand between the pair of shoe guide members when the laydown carriage is positioned in a second end reciprocation location along the reciprocation axis, the second end reciprocation location opposite to the first end reciprocation location.
6. The method of claim 4 further comprising: causing a first elastic strand of the plurality of elastic strands to slidingly engage one of the shoe strand guides of one of the shoe guide members of the pair of shoe guide members when the laydown carriage is positioned in a first end reciprocation location along the reciprocation axis; and causing the first elastic strand to slidingly engage one of the shoe strand guides of the other of the shoe guide members of the pair of shoe guide members when the laydown carriage is positioned in a second end reciprocation location along the reciprocation axis, the second end reciprocation location opposite to the first end reciprocation location.
7. A method for applying parallel flared elastics to a web comprising: providing a running web along a machine direction; providing a plurality of elastic threads to a reciprocation assembly, the reciprocation assembly comprising a laydown carriage comprising a plurality of carriage strand guides and a shoe guide assembly comprising a plurality of shoe strand guides spaced apart from each other at a variable spacing; and applying the plurality of elastic threads to the running web according to a pattern corresponding to an engagement of the plurality of elastic threads with reciprocating movement of the laydown carriage and with the shoe guide assembly, wherein the spacing between the shoe strand guides is varied to influence the laydown of the elastic strands so that a distance between successive strands of the elastic threads is varied.
8. The method of claim 7 wherein the pattern is sinusoidal.
9. The method of claim 7 wherein the pattern comprises: a first region of each of the plurality of elastic strands running in parallel to one another, the elastic strands separated from each other in the machine direction by a first distance within the first region; a second region of each of the elastic strands running continuously away from the first region along a unique angle; a third region of the plurality of elastic strands running in parallel to one another, separated by a second distance in the machine direction, wherein the second distance is larger than the first distance.
10. The method of claim 7 wherein the shoe guide assembly further comprises a pair of shoe guide members spaced apart from each other along the reciprocation axis, each shoe guide member comprising a respective portion of the shoe strand guides.
11. The method of claim 10 further comprising: causing a first elastic strand of the plurality of elastic strands to slidingly engage one of the shoe strand guides of one of the shoe guide members of the pair of shoe guide members when the laydown carriage is positioned in a first end reciprocation location along the reciprocation axis; and positioning the first elastic strand between the pair of shoe guide members when the laydown carriage is positioned in a second end reciprocation location along the reciprocation axis, the second end reciprocation location opposite to the first end reciprocation location.
12. The method of claim 10 further comprising: causing a first elastic strand of the plurality of elastic strands to slidingly engage one of the shoe strand guides of one of the shoe guide members of the pair of shoe guide members when the laydown carriage is positioned in a first end reciprocation location along the reciprocation axis; and causing the first elastic strand to slidingly engage one of the shoe strand guides of the other of the shoe guide members of the pair of shoe guide members when the laydown carriage is positioned in a second end reciprocation location along the reciprocation axis, the second end reciprocation location opposite to the first end reciprocation location.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DESCRIPTION OF THE PREFERRED EMBODIMENT
(34) Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.
(35) Referring first to
(36) This invention relates particularly to a variation in the way that leg elastics 25 and 26 (which can be ribbons) are applied. In particular, the infeed rate of leg elastics or ribbons 25 and 26 is sped up at the outer extremities of the sine curve in the machine direction so that the vertical component of the velocity of the ribbon placement is at or near the velocity of the substrate web 20 to which the ribbon is applied. This results in little to no tension upon the elastics or ribbons 25 and 26.
(37) Adhesive patterns are applied to the liner webs 20 in target areas for the leg-hole elastics 26. A spray gun assembly 29 of a type known in the art is preferably used to apply the adhesive patterns. Two sets of leg-hole, elastic strands 26 are introduced through laydown guides 30, which reciprocate from side to side past each other. The strands 26 are glued to the web sections 20, their laydown patterns following a serpentine or sinusoidal path. Laydown guides 30 then apply the strands 26, which form leg-hole elastics as the web sections 20 are carried along the face of a drum or roll 32.
(38) In a preferred embodiment of the present invention, the elastics 25 and 26 are laid down in a smooth repetitive oscillation, with a centerline along a line in the machine, and an amplitude in the cross-machine direction. In a preferred embodiment, the infeed velocity of the elastics is increased as the waveform reaches maximum amplitude, then decreases again until the laydown passes the centerline, increasing again until minimum amplitude. This variation decreases neckdown.
(39) Elastic laydown guides 28 and 30 are provided with the ability to make side-to side excursions, and the infeed of elastic 25 and 26 is provided with the ability of variable infeed speed. Elastic laydown guides 28 and 30 can be provided with the ability to make side-to side excursions by an arm that generally travels side to side e.g., by a swinging motion, or slides side to side. The side-to-side excursions of the leg-hole elastic laydown guides 28 and 30 result in generally arcuate segments of elastic strands extending on each side of the web centerline. After the nonwoven strips 22 and 24 have been applied to cover and entrap those parts of the elastics 26 that run nearest to and parallel to the inner edges of the webs 20, a second pair of slitter knives 34 is used to trim away a portion of the narrow nonwoven strips 22, 24, along with that part of the inner liner webs 20 to which they are laminated. This also removes those portions of the elastic strands 26 which are contained within the laminations. The resultant trimmed scrap strips 36 are removed from the process for disposal elsewhere.
(40) The effect of the last-described step is to remove the cut away portions of the elastic, eliminating its corresponding unwanted gathering effect from the crotch region of the garments 50. The remaining portions of the curved elastic strands create a gathering effect around the leg openings of the finished garments 50.
(41) Subsequent to the combining and trimming of the inner webs 20 and the cover strips 22, 24, the combining drum 32 carries the webs to a nip with a second combining drum 38, where the web sections 20, with their respective curved elastic patterns exposed, are transferred to and laminated adhesively against the inside face of outer liner web 12. This process entraps the curved elastic patterns 26 between the inner liners 20 and outer web 12 thereby forming a composite web 39.
(42) The composite web 39 is then provided with a pattern of adhesive in preparation to receive an absorbent insert or patch 46. The patch 46 is cut from a provided patch web 40 by a cooperation of a cutter 41 and an anvil surface on a vacuum roll 42 and rotated into position for transfer to the composite web 39 by a patch applicator 105. If the patch 46 is to be applied to the web 39, a determination explained more fully below, the patch applicator 105 forces the web 39 against the patch 46, thereby adhering the patch 46 to the web 39.
(43) Leg-hole materials 48, if not previously removed, are cut at a cutting station 47, thereby removing the material 48 contained within an approximate perimeter defined by the curved pattern of the elastics 26 and defining one half of a leg opening (with the other half of a leg opening provided in an adjacent leg-hole opening). The running composite chassis web 39 is folded, before or after cutting out of the leg holes, longitudinally along its centerline, thereby generally aligning its front waist edge with its back waist edge. The regions 53 which are to become the side seams 54 of the garments 50 are then welded by a sealing device 49 either ultrasonically or by heat. Note that the leg holes are preferably cut out before this point, leaving only a narrow zone for welding. The weld pattern is preferably wide enough to extend into both the left side seam of one garment and the right side seam of the adjacent garment. The garments 50 are then separated by passing through a cut-off knife assembly 55, which severs the web along the transverse axis of the side seam weld 53.
(44) As described above, the laydown guides 30 used to apply the leg-hole elastics 26 to the liner web 20 oscillate from side to side to apply the leg-hole elastic 26 to the liner web 20 in a generally wave-like pattern. It should be understood that due to the oscillating motion of the laydown guides 28 and 30, it is desirable to change the rate at which the leg-hole elastic 25 and 26 is introduced to the liner web 20. As shown in
(45) The incoming ribbon has variable speed, with the incoming ribbon increasing in velocity as the incoming ribbon is deposited in the curved pattern from the centerline to the maximum amplitude (its greatest distance from the centerline in the cross-machine direction towards a first boundary of the web), decreasing as the incoming ribbon is deposited in the curved pattern from the maximum amplitude to the centerline, and increasing as the incoming ribbon is deposited in the curved pattern from the centerline to the minimum amplitude (its greatest distance from the centerline in the cross-machine direction towards the other boundary of the web).
(46) In a preferred elastic laydown pattern such as shown in
(47) At least one web accumulator (not shown) can be located upstream of, or before, the leg-hole elastic guides 30, as shown in
(48) In this manner, the rate at which the leg-hole elastics 26 are being fed to the liner web 20 can be altered while the rate at which the leg-hole elastics 26 is fed to a rate adjustment apparatus 314 (not shown) remains the same.
(49) It is further contemplated that the system may include a tension control device (not shown). The tension control device is preferably sized and configured to eliminate tension in the leg-hole elastic 26 prior to applying the leg-hole elastic 26 to the liner web 20. In this manner when the leg-hole elastic 26 is applied to the liner web 20, the leg-hole elastic will not become misshapen as it would if the leg-hole elastic 26 were under tension. The tension control device can take the form of a web accumulator, or any form known in the art capable of performing such a function.
(50) In this manner, the leg-hole elastic 26 is accumulated in the tension control device when the rate of application of the leg-hole elastics 26 to the liner web 20 is slowed as described above. It is contemplated that the above-described system will provide active tension control and feed approach to change the feed of the leg-hole elastics 26 to the liner web 20 so that the leg-hole elastic is not under tension when it is applied to the liner web 20. This will result in leg-hole elastics 26 that are applied to the liner web 20 in an undistorted manner.
(51) Referring now to
(52) It should be understood that the above-described arrangement may be used to apply any type of material to a moving web in a curved pattern. In the illustrated example, the material is leg-hole elastics 26 taking the form of elastic strands; however it is contemplated that the material could take the form of elastic tape. It is further contemplated that the material could take the form of non-elastic strands or non-elastic tape.
(53) Referring now to
(54) In this embodiment, two or more series of leg band elastics 210 and 212 are laid down. Preferably waistband elastics 210 run parallel to one another, while another sequence of leg and waist elastics 212 are laid down in a curved pattern inboard of the waistband elastics 210. Preferably, the leg and waist elastics 212 are applied in a curved fashion. At what will become the leg hole opening of the diaper, the leg and waist elastics 212 are generally parallel, and each of the independent the leg and waist elastics 212 are then curved towards absorbent insert or patch 46, and increasingly separated in distance from one another the closer the leg and waist elastics 212 get to the absorbent insert or patch 46.
(55) As described above, sliding laydown guides 30 can be used to apply the leg and waist elastics 212 to the liner web 20, the laydown guides oscillates from side to side to apply the leg and waist elastics 212 to the liner web 20 in a generally wave-like pattern. Alternatively, a swing arm or series of swing arms 90 such as shown in
(56) Referring now to
(57) Similar to the configuration shown in
(58) Referring now to
(59) As shown in
(60) Referring to
(61) In the embodiment shown in
(62) Referring now to
(63) Referring generally to
(64) Referring now to
(65) Referring to
(66) During routine operation, the elastic 26 is traveling under tension, and at speed, sufficient to cause the cam weight 310 to be slightly rotated in the downstream (machine) direction. Elastic 26 is allowed to and capable of passing between the cam weight 310 and the base elastic retaining surface 312.
(67) Referring now to
(68) Similarly, as shown in
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(71) In
(72) Referring to
(73) Referring to
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(75) In a preferred embodiment, and as seen in
(76) As mentioned, the laydown carriage 518 is provided with the ability to make side-to side excursions by way of crank and arm assembly, and the infeed of elastic strands 510 is provided with the ability of variable infeed speed, as may be required. As further seen in
(77) As described above, the laydown carriage 518 used to apply elastics 510 to a web 512 oscillates from side to side to apply the elastic 510 to a web 512 in a generally wave-like pattern. Guide eyelets 520 on the laydown carriage 518 support individual elastic strands 510 during oscillation. It is to be noted that variation in the spacing, number and position of the guide eyelets 520 can be used to modify the elastic strand 510 laydown pattern and further change elastic strand 510 interaction with the shoe guides 522. For example, and as seen in
(78) Referring to
(79) It should be understood that the above-described arrangement may be used to apply any type of material to a moving web 512 in a curved pattern. In the illustrated example, the material is taking the form of elastic strands 510; however it is contemplated that the material could take the form of elastic tape. It is further contemplated that the material could take the form of non-elastic strands or non-elastic tape.
(80) The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.