US20030000620A1

Movatterモバイル変換

Info

Publication number: US20030000620A1
Application number: US10/140,156
Authority: US
Inventors: Robert Herrin; John Tharpe
Original assignee: Individual
Current assignee: R&L EINGINEERING
Priority date: 1989-11-28
Filing date: 2002-05-06
Publication date: 2003-01-02
Also published as: US6309487B1

Abstract

Disposable garments of the training pants variety include a cuff which is rolled inwardly from the plane of each leg opening. The rolled cuff feature is obtained during production by stretching a unitary elastic sheet across the machine web in a direction lateral to the direction of manufacture, and then cutting leg openings through the elastic sheet and an adjacent outer web. The machinery for manufacturing the garments includes various features which facilitate the manufacture of this garment, including a reciprocating cutting knife and an associated accumulating conveyor for providing a reciprocal motion into the reciprocal knife. The manufacturing apparatus also includes features for maintaining core pads in the desired alignment, and various other features.

Description

RELATED APPLICATIONS AND PATENTS

This application is a continuation of application Ser. No. 08/384,429 filed on Feb. 6, 1995, which is a continuation of application Ser. No. 07/884,804 filed on May 19, 1992, which is a continuation-in-part of application Ser. No. 07/442,215. filed Nov. 28, 1989, now U.S. Pat. No. 5,308,345. This application is also a related through a common parent application to application Ser. No. 08/257,768, filed Jun. 9, 1994, now U.S. Pat. No. 5,545,275 which is a continuation-in-part of application Ser. No. 07/884,804, filed May 19, 1992, abandoned, which is a continuation-in-part of application Ser. No. 07/442,215, filed Nov. 28, 1989, now U.S. Pat. No. 5,308,345.[0001]

BACKGROUND OF THE INVENTION

The present invention relates to disposable garments and methods and apparatus for making such garments.[0002]

The prior art teaches a wide variety of disposable diaper configurations, in which the finished diaper is a flat panel having adhesive tabs or the like, permitting the joinder of one end of the panel to the other, to fit the diaper panel from the infant's back, under the crotch and to the front of the waist. Examples of such arrangements are shown in the following U.S. Pat. Nos. 3,081,772 to Brooks et al; 3,417,751 to Murdoch; 4,892,528 to Suzuki et al; and 5,064,489 to Ujimoto et al.[0003]

There have also been developed in the prior art a variation of finished disposable training pants for infants, in which the finished product has opposing side seams joining the front and back panels of the garment assembly. Examples of these arrangements are shown in the following U.S. Pat. Nos. 4,743,239 to Cole; 4,743,241 to Igaue et al; 4,646,362 to Heran et al; 4,938,757 to Van Gompel et al; and 5,055,103 to Nomura et al; and 5,064,421 to Tracy.[0004]

The aforementioned U.S. Pat. No. 4,743,241 to Igaue et al discloses an elastic sheet adhered across the panel adjacent to the opposing leg openings, which serves as a liquid barrier for body fluids leaking from the center absorbent pad. A similar arrangement is disclosed in U.S. Pat. No. 3,417,751 to Murdoch.[0005]

SUMMARY OF THE INVENTION

The present invention is directed to a method of making disposable garments, particularly of the training pants variety, which include a rolled cuff inwardly from the plane of each leg opening, at least about the lower portion of the leg opening. Further, the present invention is directed to methods for achieving this rolled cuff feature in a low cost and facile manner. The present invention also has the objective of providing methods for achieving improvements and efficiencies in the manufacture of disposable garments of all types, including both disposable diapers, training pants, and incontinent garments for those who are elderly or infirmed. The present invention advantageously includes a method of making disposable garments. The method preferably includes conveying a carrier layer having a pair of opposing edges positioned to extend along a direction of manufacture. The method can also advantageously include disposing a plurality of elongate absorbent pads positioned in spaced-apart relation on the carrier layer between the pair of opposing edges with a direction of elongation extended transverse to the direction of manufacture. The method can further advantageously include forming a plurality of openings in the carrier layer, each of the plurality of openings positioned between respective adjacent pads and defining a leg hole associated with each adjacent pad. The method can still further advantageously include folding the carrier layer and the pads positioned thereon generally into two halves extending along a fold line positioned intermediate the pair of opposing edges and generally parallel with the direction of manufacture. The method can also include joining the two halves together along a plurality of seam lines, two adjacent seam lines extending generally transverse to the direction of manufacture between respective adjacent pads to as to intersect each of the plurality of openings and pair of opposing edges. The method can still further advantageously include severing the carrier layer into a plurality of individual garment units between said adjacent seam lines.[0006]

In one form, the method of making the disposable garment in accordance with the present invention includes making a disposable garment having a panel of a material at least a portion of which is liquid impervious, the panel defining leg openings. The garment is provided with elastic means extending continuously about the peripheral edge of each leg opening with the elastic means including a sheet of an elastic material stretched along an inside surface of the panel and about a substantial portion of the periphery of the corresponding leg opening, the elastic sheet being under sufficient stretch to draw the periphery of the leg opening into a curved elastic cuff when the garment is fitted about an infant. In this arrangement, the elastic sheet extends continuously around and to the peripheral edge of the corresponding leg opening.[0007]

In another form, the elastic sheet extends about the lower portion of the leg opening, with plural elastic bands extending about the remaining periphery of the leg opening at the upper portion on either side of the leg opening. In this arrangement, the elastic bands preferably also extend across the area covered by the corresponding elastic sheet, then laterally across the crotch area of the panel and then across a portion of the area covered by another elastic sheet about the opposing leg opening, with a similar pair of elastic bands being also disposed around the other side of the two leg openings.[0008]

A third form of making the disposable garment employs a second layer of elastic sheet extending between the leg openings, and longitudinally stretched between the leg holes. The second stretched elastic layer avoids the necessity for providing the elastic bands of the type described above, while at the same time providing a uniform gathering of material in the crotch area of the garment.[0009]

Preferably, the elastic sheet material is under a stretch on the order of five ounces per lineal inch for each inch of cross-width when installed across the panel, and extends at least 0.5 inches from the peripheral edge laterally across that portion of the panel where the elastic sheet is deposited.[0010]

In the manufacture of the garments, a unitary elastic sheet is stretched across the machine web in a direction lateral to the direction of manufacture, the elastic sheet having dimensions so as to cover an area of the web where leg openings for two adjacent garments will later be formed. Leg openings are then cut through each elastic sheet in the outer web, each leg opening lying within the boundaries of the corresponding elastic sheet and defining the peripheral edges of two leg openings, one each for the adjacent garments. The web is then later folded in half, so that the elastic sheet extends continuously around the leg opening. In this form of manufacture, the direction of stretch of the elastic sheet for each leg opening thus is generally parallel to the edge of the opening along the lower portion, the direction of stretch extending somewhat laterally away from the peripheral edge along that portion closest to the waist opening of the garment. Appropriate seams are formed along the sides between the front and back of the garment from the waist opening to the upper portion of each leg opening.[0011]

The present invention also is directed to manufacturing methods which includes a sequential series of operations formed at individual stations, or “sections”, where the method and apparatus coact with the materials which make up the disposable garments.[0012]

One of the features of the present invention with respect to methods for manufacturing such garments is the inclusion of a reciprocating “guillotine” cutting knife for severing the continuous web of absorbent material into individual pads. The use of a reciprocating knife reduces the hardness and sharpness of the edge of the pad, with respect to conventional rotary cutters. In order to accommodate the use of the reciprocating cutting blade, the present invention utilizes a conveying system in which the web of materials forming the pads are passed into an accumulator section which permits an elevated continuous feed from overhead onto a vacuum conveyor; the vacuum conveyor is then operated intermittently as required by the operation of the reciprocating cutting knife. The accumulator utilizes a retaining flap to keep the degree of accumulating “bend” in the continuous pad material to an acceptable level. The material forming the pad web is maintained against the vacuum conveyor with a curved bar extending in the direction of manufacture; the vacuum conveyor itself utilizes a woven material as the conveyor surface, with a fixed vacuum plate for drawing the pad web down against the woven conveyor surface. The reciprocating action of the knife across the laterally extending pad web is operated by an eccentric drive mechanism, and the cutting aperture below the reciprocating knife blade is angled in a V-shape, in order to facilitate a smooth cut.[0013]

After cutting of the individual pads, the pads are then conveyed to a combining station and adhered to an outer carrier layer, or web. In order to insure that the pads are delivered exactly in a straight format to the combining station, the pad conveyor between the cutter and the combining section is provided with means for straightening any misaligned pads moving across the conveyor; this objective is achieved in a conveyor which also further achieves the objective of reaching near the throat of the reciprocal cutting knife, in order to receive each cut pad. This is achieved using multiple thin, plastic webbing strips for the conveyor surface, and a chain and dog drive positioned underneath the webbing conveyor, the chain having an eccentric drive to move each dog first slowly, then faster, then slowly again. The chain drives extend parallel with the thin webbing, with the dogs extending through the webbing and into engagement with each pad. In operation, each straightening dog rises slowly between two of the conveyor webbing strips, then speeds up to engage the backside of a corresponding pad on opposite sides of the webbing, thereby straightening any misaligned pad. As the pad then nears the discharge end of the webbing conveyor, the eccentric drive of the chain assembly slows down each dog relative to the speed of the webbing conveyor, thereby causing each dog to effectively back away from the respective pad; each dog then is rotated below the level of the webbing conveyor.[0014]

Following the edge folding operation, the machine web is passed into a leg hole cutting section, where leg holes are cut through the inner and outer non-woven layers, the polyvinyl liner and centrally through the elastic sheets. The dimensions of the elastic sheet are such as to extend outside of the leg hole dimensioned on the order of at least 0.5 inches, or more, as discussed above. Further, it will be appreciated that each leg hole defines a corresponding leg opening for adjacent garments which are eventually severed from the machine web. It is preferred that the leg hole cutting operation take place with a vacuum underneath the cutter, in order to draw away the waste product of that cutting operation.[0016]

Following the cutting of the leg holes, the machine web is then folded in half and passed into a seam weld section, where two adjacent seams are formed using an ultrasonic welder. In one arrangement, the anvil of the ultrasonic welder is heated to a temperature somewhat below the melting temperature of the polyvinyl liner, and the teeth on the anvil are sharpened to obtain penetration through all of the layers. The combination of the sharpened anvil teeth and the elevated temperature provide a highly reliable seam weld.[0017]

A second form of the ultrasonic seam welder utilizes an inflatable bladder behind the anvil, with the ultrasonic horn driven by an eccentric cam. These features permit a greater dwell time during the seaming operation.[0018]

The products are then passed into a unit cutter section, where the machine web is severed into individual garments.[0019]

These and other features of the present invention will be understood by those skilled in the art from the following accompanying drawings and description.[0020]

THE DRAWINGS

FIGS. 1A and 1B are flow charts illustrating the system, method and apparatus of the present invention, as used in the manufacture of disposal garments, and in which the direction of manufacture is from left to right in both Figures.[0021]

FIGS. 2A and 2B are top and side views, respectively, illustrating the component portions and manner of fabrication of disposable garments in accordance with the present invention and in which various locations along the direction of operation in FIGS. 2A and 2B generally correspond to the location of the various sections of the system illustrated in FIGS. 1A and 1B, and in which the direction of manufacture is from left to right in both Figures.[0022]

FIG. 3 is a side elevation, partially in cross section, of a disposable garment in accordance with the present invention.[0023]

FIG. 4 is a cross section of a portion of the disposable garment shown in FIG. 3, taken along the line[0024]44.

FIG. 5 is another cross section of a portion of the disposable garment shown in FIG. 3, taken along the line[0025]5-5.

FIG. 6A is a top view of a second form of a disposable garment in accordance with the present invention.[0026]

FIG. 6B is a top view of a third form of a disposable garment according to this invention.[0027]

FIG. 7 is a side elevation illustrating the accumulator section of the system shown in FIG. 1A, and in which the direction of manufacture is from left to right in the Figure.[0028]

FIG. 8 a front elevation and[0029]

FIG. 9 is a side elevation, both illustrating features of the reciprocal knife cutting section of the system of FIG. 1A.[0030]

FIG. 10 is a top plan view of the pad conveyor section of the system shown in FIG. 1A.[0031]

FIG. 11 is a cross section of a portion of the conveyor shown in FIG. 10, taken along the lines[0032]11-11.

FIGS. 12 and 13 are top and side views, respectively, of the stretcher and applicator section of the system shown in FIG. 1A, and in which the direction of manufacture is from the bottom upwardly in FIG. 12 and right to left in FIG. 13.[0033]

FIG. 14 is a front view of a portion of the edge-folding section in the system shown in FIG. 1A, and FIG. 15 is top view of that edge folding section with the direction of manufacture from the top downwardly.[0034]

FIG. 16 is a perspective view illustrating one form of the seam welding section of the system in FIG. 1B.[0035]

FIGS. 17A and B, respectively, top plan and rear elevational views of a second embodiment of a seam welding section.[0036]

FIG. 17C is a schematic top plan view illustrating the movement of the horn and anvil of a second embodiment of a seam welding section.[0037]

In FIGS.[0038]7-16, three digit reference numerals are used to identify specific features of a corresponding portion of the system shown in FIGS. 1A and1B, and in which the reference numeral for the section in FIGS. 1A and 1B has the same first two digit reference numeral (for example, in FIG. 7, three

digit reference numerals

181,182 and so forth refer to specific features of theaccumulator section18 in FIG. 1A).

DETAILED DESCRIPTION

The apparatus and method for making disposable garments will now be described with reference to FIGS. 1A and 1B, with concurrent reference to FIGS. 2A and 2B. Thereafter, three forms of disposable garments made according to the method and using the apparatus is described with reference to FIGS.[0039]3-6A and B, followed by a description of specific features of the apparatus as shown in FIGS.7-16, and an alternate seam weld construction in FIGS.17A-C.

The Method and Apparatus

Noting FIGS. 1A and 2A, the apparatus[0040]10 includes a fold section12 using conventional techniques to fold anabsorbent core material16 and anouter tissue14, in order to form a web ofabsorbent pad material15. The output of the fold section is passed into anaccumulator section18, which is shown schematically in FIG. 1A to be elevated with respect to the fold section12, and the downstreampad cutter section20. As illustrated in FIG. 2A, theabsorbent pad web15 is cut intoindividual pads22, each having aforward edge24 and arear edge26, by cutting along a direction lateral to the direction of manufacture, as illustrated byarrows30. The individually cutpads22 are passed into apad conveyor section28, and then to a combiningsection32.

In the combining[0041]

section

32, anouter non-woven layer34 is extended along the direction ofmanufacture30, and provided with an appropriate adhesive, generally over the entire exposed surface of thenon-woven layer34. Waistbandelastic strips46 are extended along the adhesive-coated non-wovenouter layer34, again in the direction of manufacture shown byarrows30, in order to provide a waistband elastic in a conventional manner. A liquid impervious liner48 (for example, polyvinyl) is extended across the adhesive-coatednon-woven layer34, and thenindividual pads22 are affixed to the exposed surface of the liner, using appropriate adhesives. Theliner48 either alone or in combination with theouter non-woven layer34 serves as a carrier layer during the manufacturing operation.

In accordance with the present invention, there is provided a source of[0042]

elastic sheet material

40, for example polyurethane foam or polyethylene sheeting, which is extended into a stretcher and applicator section38, which is described in greater detail below with reference to FIGS. 12 and 13. As shown in FIG. 2A, the stretcher and applicator38 cuts the elastic sheet intoindividual sheet segments40, while simultaneously stretching eachsheet segment40 in a direction lateral to the direction ofmanufacture30, as is depicted byarrows42 in FIG. 2A, and generally under the stretch conditions discussed above; that is, a stretch on the order of five ounces per lineal inch for each inch of cross-width (i.e., twenty-five ounces for a five inch length of one inch wide elastic). The individualelastic sheet segments40 may be affixed to either the liquidimpervious liner48, or to theouter non-woven layer34, as shown in FIG. 2A. Thepolyvinyl liner48 and theindividual pads22 are respectively affixed to theouter non-woven layer34 and theliner48 with a conventional adhesive36.

The output of the combining section is fed into another section where an[0043]

inner non-woven layer

50 is fixed to the assembly by an adhesive across theliner48. As is shown in FIG. 2A, theinner non-woven layer50 and theliner48 have a lateral dimension somewhat less than the corresponding dimension of theouter non-woven layer34, so that the outer non-woven layer has

peripheral edge portions

33,35 extending beyond the periphery of the other two layers. After deposition of the inner non-woven layer at section44, the assembly is then fed into anedge folding section52. As schematically depicted in FIG. 2A, the

peripheral edge portions

33,35 of theouter non-woven layer34 are then folded across the periphery of theinner non-woven layer50 and joined thereto with an adhesive, as described in greater detail below with reference to FIGS. 14 and 15.

The output from the[0044]

edge folding section

52 is then fed into a leghole cutting section54, which is operated under a slight vacuum at55, so as to remove the scrap without interfering with the manufacture of the assembly. Noting FIG. 2A, eachleg hole56 is cut centrally in the web defined by the

layers

34,48 and50 betweenadjacent pads22, and centrally within the peripheral boundary of a correspondingelastic sheet40; preferably, the dimensions of the leg hole and the elastic sheet are selected so that a minimum of 0.5 inches of the elastic sheet, and suitably an even greater dimension, extend from the peripheral edge of theleg hole56 to the boundary of theelastic sheet40. It will of course be appreciated that the cutting of theleg hole56 centrally in theelastic sheet40 insures that the elastic sheet extends to the very edge of the leg hole. As will be discussed in greater detail below with reference to FIGS.3-5, this particular feature enables the disposable garment to achieve a desirable inwardly rolled cuff which assists in defining a liquid barrier.

After passing out of the leg[0045]

hole cutting section

54, the assembly is fed into a web folding section58, where the entire web is folded upon itself, as depicted along the left hand side of FIG. 2B. The web is then fed into aseam welding section60, where parallel seams are formed between the upper edge of the web and the upper extremity of eachleg hole56; preferably, this is achieved utilizing an ultrasonic welder and a rotating anvil which is heated to a temperature slightly below the melting point of thepolyvinyl liner48, and below the ignition temperature of the

non-woven layers

34 and50.

The output from the seam welding section is then passed into a unit cutter section[0046]66, where the web is cut alongline68 intoindividual garments70. Each garment is then conveyed into a blower section67 where air is blown into the individual garment is subjected to a vacuum at69 to draw the intermediate seam welds inwardly to form a compact unit for packaging purposes.

A First Embodiment of the Disposable Garment (FIGS.[0047]3-5)

Construction details of a first form of the[0048]

disposable garment

70 are depicted in FIGS.3-5. As constructed, thegarment70 includes awaistband opening72, afront panel74, an opposingrear panel76 and acrotch area78; it will of course be understood that the front and back panels and the

crotch area

74,76 and78 are formed from the assembly of materials in accordance with the method depicted in FIGS. 2A and 2B, and includes (as shown in the cut away portion in FIG. 3) theouter non-woven layer34, theliner48,absorbent pad22 andinner non-woven layer50, with theelastic waistbands46 andseam64.

The portion of the[0049]

elastic sheet

40 remaining with theindividual garment70 after formation of theleg opening56, folding of the web and welding of theseam64 is depicted by a dotted line in FIG. 3.Arrows42 also depict the direction of stretch of theelastic sheet40. As discussed above, the cutting of theleg opening56 through the field of theelastic sheet40 is accomplished so as to extend to the extreme periphery of theopening56. This, together with the folding of the web to form the front and

back panels

74,76 relieves the stretching of theelastic sheet40 along the periphery of theleg opening56, and causes the elastic sheet along the periphery to roll into an inwardly-directed cuff along the periphery of theleg opening56. However, because of the variance of the stretch represented byarrows42 from thelower portion80 of theleg opening56 to theupper portion82, the degree of roll of the cuff varies from the lower portion to the upper portion. This is shown by comparison of FIGS. 4 and 5, where thelower portion80 of the rolled cuff is shown to be greater than theupper portion82 of FIG. 5. This variance of the rolled cuff from the lower portion is desirable, since the upper portion does not require as great a roll in the cuff for purposes of providing a liquid barrier, and also provides greater comfort to the person wearing thegarment70.

Other Forms of the Disposable Garment Construction (FIGS. 6A and B)[0050]

A second alternate form of construction of the disposable garment in accordance with the present invention is shown in FIG. 6A and referred to generally by the[0051]

90 includes various features of thegarment70 shown in FIGS.3-5, which are referred to by the same reference numerals, including waistband elastic46, seams62,64,inner non-woven layer50,pad22 andleg openings56. The construction ofdisposable garment90 is different from the construction ofgarment70 in FIG. 3 through the use of

elastic bands

92 and94 which extend continuously around the periphery of opposite sides of each leg opening and across a portion of the same area covered by

elastic sheets

96,98 and also across the crotch area of thegarment90 to theopposite leg opening56. Further, the

elastic sheets

96,98 may be drawn back slightly from the

respective seams

64,62 so as to extend essentially about the peripheral edge of the lower portion of theleg opening56 after being folded.

A third form of construction of a disposable garment in accordance with the present invention is shown in FIG. 6B and referred to there by the reference numeral[0053]91.

The disposable garment[0054]91 also includes the various features of the

garments

70 and90 shown in FIGS.3-5 and6A, to the extent that those various features are referred to by the same reference numerals. Additionally, the garment91 includes a second layer of elastic sheeting extending between the leg openings, and longitudinally stretched in the direction of thearrows95 in FIG. 6B. The stretchedelastic layer93 avoids the necessity for providing the

elastic bands

92 and94 of FIG. 6A, while at the same time providing a uniform gathering of material in the crotch area of the garment91.

The Accumulator Section (FIG. 7)[0055]

Details of the[0056]

accumulator section

18 of FIG. 1A are shown in FIG. 7.

As shown on the left hand side of FIG. 7, the[0057]

absorbent pad web

15 is extended across

elevated rollers

181,182 which operate continuously to receive the feed of theweb15. The

rollers

181,182 then feed theweb15 downwardly across anindexing conveyor183, which preferably consists of a wire mesh extending across a fixedvacuum plate184 having holes therein permitting a vacuum to be drawn, as shown by arrows. theaccumulator section18 further includes acontrol plate185 pivoted at186, and extending across theweb15 somewhat below the

continuous feed rollers

181,182. Similarly, there is apressure rod187 pivoted at188 extending across theabsorbent pad web15 and over theindexing conveyor183.

In operation, the[0058]

absorbent pad web

15 is drawn into fixed engagement with the mesh surface of theindexing conveyor183 via thevacuum plate184. Theindexing conveyor183 is operated on a “stop-start”, or intermittent basis, as required by the operation of thereciprocating cutting blade20 described below in greater detail with reference to FIGS. 8 and 9, but the details of which are also depicted in FIG. 7. Thus, the

rollers

181 and182 are continuously feeding theweb15 onto a conveyor which only operates on an intermittent basis; therefore, theweb15 is subjected to a buckling, as shown below thecontrol plate185. The degree of buckle is controlled by theplate185, to insure that the direction of the web continues along the surface of theintermittent indexing conveyor183. Thepressure rod187 also insures that any buckling does not extend beyond the central area of theindexing conveyor183.

As shown on the right hand side of FIG. 7, the[0059]

indexing conveyor

183 forces theabsorbent pad web15 across a fixedmandrel189 in the throat of thecutting section20, described next.

The Pad Cutting Section (FIGS. 8 and 9)[0060]

As discussed briefly above, the[0061]

pad cutting section

20 utilizes a reciprocating “guillotine”-type of cutter, which achieves certain benefits with respect to the formation of the cut edge in theabsorbent pads22.

Referring to FIG. 8, the cutting[0062]

section

20 includes ablade202 terminating in acutting edge201, and carried by across plate203 extending across the machine direction. Theplate203 is carried by reciprocating

rods

204,206 which are supported by

springs

205,207 for biasing in an upward direction. The

reciprocating rods

204,206 are supported by respective bearing blocks208,210. As shown in the front view of FIG. 8, themandrel189 has a V-configuration, such that theabsorbent pad web15 is sheared downwardly from each side to the central portion of the mandrel.

Noting FIG. 9, the reciprocating motion of the[0063]

rods

204,206 is controlled by an eccentric215 rotating about ashaft216, and engaging arotating element213 mounted on a pivot axis214 and which is supported by ayoke212 at the upper extremity of each

rod

204,206. The use of an eccentric cam surface to control the operation of thecutting blade201, together with the shape of the cutting throat defined bymandrel189 insures a smooth, even and sharp cut through theabsorbent pad web15, to defineindividual pads22.

Pad Conveyor Section (FIGS. 10 and 11)[0064]

Details of the[0065]

pad conveyor section

28 of FIG. 1A are shown in FIGS. 10 and 11. The pad conveyor includes a pair ofrotating shafts281,282 which extend laterally across the direction of manufacture, and support plural vinyl conveyor straps283 along the manufacturing direction. As is depicted in FIG.7, theconveyor webs283 are extended into close proximity to the throat of thepad cutter20.

A pair of chain drives[0066]284 are supported parallel to and underneath thewebbing283, eachchain drive284 spaced between two of the webbing strips. The chain drives are supported by

shafts

285,286 and an eccentric drive287 (FIG. 11). Plural straighteningdogs288 are dimensioned vertically to extend upwardly from the respective chain drives284 and above the level of the webbing strips283. As is depicted in FIG. 10, theeccentric drive287 imparts a “slow-fast-slow” pace to the movement of the straightening dogs, in order that the dogs may first extend upwardly betweenadjacent strips283, then be speeded up to engage the backside of acorresponding pad22 to straighten the position of any misaligned pad across the lateral direction, and then slow down and back away from the back edge of the corresponding pad, before rotating underneath the chain drive as shown in FIG. 11. Of course, thepad22 is then discharged from thepad conveyor28 on the right hand side of FIG. 10, and progresses to the combining section32 (FIG. 1A).

The stretcher and applicator section is described in application Ser. No. 07/442,215 which is incorporated her by reference.[0067]

Stretcher and Applicator Section (FIGS. 12 and 13)[0068]

As shown in FIG. 13, a web of the elastic sheet[0069]40 (i.e., urethane foam or polyethylene) is passed into aknife roller381 havingknife blades382, at which point the web of elastic sheet is cut intoindividual sheet segments40. theknife roller381 cuts theelastic sheet lengths40, and vacuum chucks383 on anvil384 carries theelastic sheet lengths40 to atransfer roller385.

Noting both FIGS. 12 and 13, at an appropriate transfer point, the individual[0070]

elastic sheets

40 are received along the surface of thetransfer roller385 which also includes vacuum chucks386. The vacuum chucks386 hold the individualelastic lengths40 across the transfer surface of thetransfer roller385, until such time as theindividual sheets40 are fed into anentry point387 of stretching

rollers

388,389. As is particularly shown in FIG. 12, the crosswise dimension of the transfer surface of thetransfer roller385 is substantially less than the lengthwise dimension of eachelastic sheet40, and is approximately equal to or less than the spacing between the stretching

rollers

388,389 at theentry point387.

The stretching[0071]

rollers

388,389 are mounted on

respective hubs

390,391, each of which may be individually adjusted at an outwardly skewed angle from theentry point387 to anexit point392. Each rotating stretching

roller

388,389 also includes a corresponding

peripheral groove

393,394 across which passes a corresponding smooth surface

gripping belt

395,396, each of which is dimensioned to fit within the corresponding

peripheral groove

393,394. As each

gripping belt

395,396 approaches the periphery of the

corresponding roller

388,389 at theentry point387, an adjacent one of theelastic sheets40 are picked up at the transfer point by the gripping belts and pinched into the

corresponding groove

393,394. As the skewed

rollers

388,389 are rotated, the gripping belts hold the sheets in place, and the skewed angle effectuates the desired degree of stretching. Thereafter, as is shown in FIG. 13, theindividual sheets40 are discharges atarea392 onto the web of theouter non-woven layer34.

Edge Folding Section (FIGS. 14 and 15)[0072]

The[0073]

edge folding section

52 includes apressure roller522, under which the combined web assembly including theouter non-woven layer34, liner (not depicted in FIG. 14),absorbent pad22 andinner non-woven layer50 are all passed. As illustrated in FIG. 14, thepressure roller522 includes inwardly tapered, low friction surfaces which are dimensioned to engage only the

extended edge portions

33,35 of theouter non-woven layer34. Because the tension of the web is relieved by thetaper526 on the incaps524, the

edge portions

33,35 are lifted upwardly. Thereafter, the web is passed acrossedge folders528, each of which includes a taperedfold surface530 for receiving the

elevated edge portions

33,35. Aglue joint532 is then directed across the outer edge portions of theinner non-woven layer50 for receiving the folded

edges

33,35 of theouter non-woven layer34.

Seam Weld Section (FIGS. 16) and[0074]17A-C

As discussed above, the seam weld section[0075]60 (FIG. 1B) utilizes an ultrasonic welder includingweld head602 having aface604 with protruding weld pins606. In accordance with the present invention, thepins606 are sharpened to a sufficient degree to insure penetration through the entire web assembly, including theouter non-woven layer34,elastic sheet40,liner48 andinner non-woven layer50. Further in accordance with the present invention, the ultrasonic welder is operated in conjunction with arotating anvil607 having ananvil face608 which is heated by aninternal heating coil609 to a temperature which is slightly below the melting temperature of thepolyvinyl liner48, and of course below the ignition temperature of the inner and outer

non-woven layers

34,50. It has been found that this particular arrangement shown in FIG. 16 provides desirable seam welds in a facile manner.

A second form of the seam welding section is depicted in FIGS.[0076]17A-C. In this arrangement, the seam welding section includes opposing pairs of rotating

drive wheels

704,706 and716,718. Each pair of drive wheels is pivotally connected respectively at710,712 and722,724 to a

corresponding drive rod

708,720. (As shown in FIG. 17B, each of the drive wheels is in turn rotated by a corresponding shaft and gear arrangement, including correspondinggears795,707 and717,719, with each the drive gear being driven by arespective pinion703,715).

A conventional[0077]

ultrasonic horn

714 is mounted on the forward extremity of thedrive rod708, and a conventionalultrasonic anvil726 is mounted at the extremity of thesecond drive rod720. In accordance with the present invention, the anvil is coupled to aback plate730 via anair bladder728 which is capable of being alternately inflated and deflated from anair supply729. This construction permits theanvil726 to be inflated outwardly toward thehorn714, and also imparts a significant degree of “give” to theanvil726 via theair bladder728.

In operation, rotation of each pair of[0078]

drive wheels

704,706 and716,718 results in the reciprocal movement of the

corresponding drive rod

708,720 toward the machine web, the web being represented byarrow702 in FIGS. 17A and 17C. It will of course be appreciated by those skilled in the ultrasonic welding art that without the presence of thecompressible bladder728, there is only one tangential point where theultrasonic horn714 and theanvil726 may come in contact with each other, in order to avoid any damage to either part. However, with the provision of theinflatable bladder728, theanvil726 is imparted with a significant degree of “give” or compressibility, thereby permitting thehorn714 and theanvil726 to be in contact with each other for a much greater period of time during movement of the web (represented by arrow702) along the direction of travel. This results in a much better forming of weld seams like

seam

62 and64 in FIG. 2B. This greater dimension of contact is represented by dimension D in FIG. 17C, in which circles731 and732 respectively depict the circular motions of thehorn714 andanvil726 during movement of the

drive rods

708,720.

Summary[0079]

There has been disclosed above a system and method for manufacturing disposable garments, the system including various apparatus features. Further, the[0080]

disposable garments

70 and90 of FIGS.3-6 provide a cuff which extends inwardly from the plane of the leg hole, to provide a liquid barrier at least in the region of the lower portion of the leg opening. This is achieved utilizing an elastic sheet which may be stretched to a sufficient degree to insure achieving the desired rolled cuff feature, and in a manner which lends itself to high speed, low cost manufacturing techniques.

This concludes the description of the preferred embodiments. A reading by those skilled in the art will bring to mind various changes without departing from the spirit and scope of the invention. It is intended, however, that the invention only be limited by the following appended claims.[0081]

Claims

That which is claimed:

1. A method for making disposable garments, the method comprising the steps of:

conveying a carrier layer having a pair of opposing edges positioned to extend along a direction of manufacture;

disposing a plurality of elongate absorbent pads positioned in spacedapart relation on the carrier layer between the pair of opposing edges with a direction of elongation extending transverse to the direction of manufacture;

forming a plurality of openings in the carrier layer, each of the plurality of openings positioned between respective adjacent pads and defining a leg hole associated with each adjacent pad;

folding the carrier layer and the pads positioned thereon generally into two halves extending along a fold line positioned intermediate the pair of opposing edges and generally parallel with the direction of manufacture;

joining the two halves together along a plurality of seam lines, two adjacent seam lines extending generally transverse to the direction of manufacture between respective adjacent pads so as to intersect each of the plurality of openings and pair of opposing edges; and

severing the carrier layer into a plurality of individual garment units between said adjacent seam lines.

2. The method recited inclaim 1 further comprising the step of forming

the carrier layer prior to the step of disposing the elongated absorbent pads onto the carrier layer.

3. The method recited inclaim 2 wherein the carrier layer forming step comprises conveying a liquid impervious liner along the direction of manufacture.

4. The method recited inclaim 3,_wherein the carrier layer forming step further comprises conveying non-woven inner and outer liquid permeable layers along the direction of manufacture, the liner and each of the plurality of pads being positioned between the non-woven inner and outer layers, and the method further comprising the steps of:

adhering each of the plurality of elongate pads to the liner; and

adhering the non-woven inner and outer layers to opposing sides of the liner.

5. The method recited inclaim 4, wherein the outer non-woven layer includes a dimension transverse the direction of manufacture which is greater than a corresponding dimension of the liner and a corresponding dimension of the inner non-woven layer so, that the outer non-woven layer defines edge portions extending beyond respective pairs of edges of the liner and the inner non-woven layer, and wherein the carrier layer forming step further comprises:

folding the edge portions of the outer non-woven layer, said edge portions including said pair of opposing edges, respectively so as to overlie the edges of the inner non-woven layer respectively; and

adhering the folded edge portions of the outer non-woven layer to the respective edges of the inner non-woven layer.

6. The method recited inclaim 5 wherein the folding the edge portions step comprises the steps of:

providing a fold roller having outwardly tapered ends, a lateral dimension of each tapered end corresponding to the dimension of the edge portions of the outer non-woven layer;

passing the non-woven inner and outer layers under the fold roller under sufficient tension to cause each edge portion of the outer non-woven layer to conform to the shape of the adjacent tapered end and thereby exit the roller with each edge portion of the outer non-woven layer extending upwardly from a remainder of the liner and the inner non-woven layer; and

engaging each raised edge portion immediately downstream from the fold roller and positioning each raised edge portion so as to overlie the edges of the inner non-woven layer.

7. The method recited inclaim 5 further comprising the step of elasticizing the edges of the non-woven inner and outer layers to form a waistband.

8. The method recited inclaim 7 wherein the leg hole forming step defines an edge about each leg hole, and further comprising the step of elasticizing the edge of each of the leg holes.

9. The method recited inclaim 8 wherein the step of elasticizing the edge of each of the leg_holes comprises the steps of:

stretching a plurality of strips of elastic material;

depositing at least one of the plurality of strips of the stretched elastic material on the carrier layer adjacent the leg holes; and

depositing at least one of the plurality of strips of the stretched elastic material along the edge of each of the leg holes.

10. The method recited inclaim 8 wherein the step of elasticizing the edge of each of the leg_holes comprises the steps of:

longitudinally stretching each of a plurality elastic strips by gripping without penetrating at least one of its ends;

passing each of the plurality of stretched elastic strips and the liner one with respect to the other while continuing the stretching step; and

securing each of the plurality of stretched elastic strips to the liner.

11. The method recited inclaim 10 wherein the stretching step further comprises pinching without penetrating at least one of the ends of each of the plurality_of elastic strips against a roller surface, and then rotating the roller surface at an outwardly skewed angle.

12. The method recited inclaim 11 wherein the pinching step comprises pressing a continuous belt against the roller surface with the at least one of the ends of each of the plurality of elastic strips positioned between the belt and the roller surface.

13. The method recited inclaim 10 wherein the longitudinally stretching step comprises:

passing a continuously web of the elastic material to a cutting means and cutting the web into a plurality of elastic strips;

continuously transferring the plurality of elastic strips from the cutting means to a pair of spaced apart, continuously rotating rollers; positively engaging each end portion of each elastic sheet length to a corresponding one of the spaced rollers without penetrating the elastic sheet length; and

stretching each elastic sheet length during rotation of the rollers.

14. The method recited inclaim 13 wherein the transferring step comprises engaging each of the plurality of elastic strips to a moving transfer surface having a lateral width less than a dimension between portions of the spaced rollers, and less than the dimension of a elastic strip positioned across the transfer surface.