US3666611A - Absorbent pad - Google Patents

Abstract

D R A W I N G
ABSORBENT PAD HAVING A PULP FILER, WADDING ENVELOPE, AND BODY CONTACTING COVER OUTSIDE THE ENVELOPE WHICH IS SHORTER THAN THE PAD IS LONG, THUS TO LEAVE END MARGINS OF THE PAD UNCOVERED. THE APARATUS AND METHOD FOR FABRICATING SUCH A PAD INVOLVES SUPERIMPOSING SEPARATE PULP MATS, ONE OF WHICH IS COMPRESSED BEFORED SUPERIMPOSITION IN ORDER THAT THE COMPRESSED MAT FUNCTIONS AS A FLOW DISTRIBUTION PLY, SUBDIVIDING THE SUPERIMPOSED MATS INTO DISCRETE PAD FILLERS WITH GAPS THEREBETWEEN, ENCASING THE SPACED PAD FILTERS IN A WADDING ENVELOPE WHICH IS CONTINUOUS ACROSS THE GAPS, CROSS SEALING THE ENVELOPE ACROSS THE GAPS TO FORM A CONTINUOUS WADDING ENVELOPE TUBE WITH LINKS INTERCONNECTING THE SPACED FILLER PADS, AND APPLYING THE BODY CONTACTING COVER SHEET THERETO.

Description

C. G. JOA

ABSORBENT PAD May 3o, 1972 4 Sheets-Sheet 1 Filed Aug l5 J 969 INVENTOR C027* 6. Jon

@YMALL/wm ATT o 52H EYS C. G. JOA

ABSORBENT PAD May 30, 1972 4 Sheets-Sheet 2 FiLed Aug. l5 .1969

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INVENTO R ATTORNEYS dier 6m .Jon

BY w, W, lmd'cww C. G. JOA

ABSORBENT PAD May 30, 1972 4 Sheets-Sheet 3 Filed Aug. l5. 1969 )NVENTO Z Caer 6. J0@

d ATTO QNEYS May 30, 1972 c. G. JOA 3,666,611

AUSORBENT PAD Filed Aug. 12.1. 19m

4 Sheets-Sheet 4 rm/Emol @der 6. Jon

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AT TQRMEYS United States Patent() U.S. Cl. 161-147 4 Claims ABSTRACT OF THE DISCLOSURE Absorbent pad having a pulp filler, Wadding envelope, and body contacting cover outside the envelope which is shorter than the pad is long, thus to leave end margins of the pad uncovered. The apparatus and method for fabricating such a pad involves superimposing separate pulp mats, one of which is compressed before superimposition in order that the compressed mat functions as a flow distribution ply, subdividing the superimposed mats -into discrete pad llers with gaps therebetween, encasing the spaced pad fillers in a wadding envelope which is continuous across the gaps, cross sealing the envelope across the gaps to form a continuous wadding envelope tube with links interconnecting the spaced ller pads, and applying the body contacting cover sheet thereto.

SUMMARY OF THE INVENTION In accordance with the present invention, an improved pad is produced which has a central compressed or embossed pulp layer which enhances longitudinal and lateral ow distribution and an external body contacting cover sheet which is made shorter than the pad is long in order to cover only the central part of the pad and leave end margins of the envelope exposed. The body contacting cover desirably comprises a smooth strip of non-Woven fabric which is worn against the body and prevents pilling of the pulp and wadding.

In fabricating the pad, multiple lanes of pulp mat are stripped off of a forming screen onto the laterally adjacent ends of horizontally exible conveyors. The opposite ends of these conveyors are brought into vertically overlapping relation by horizontally flexing intermediate portions of the conveyors. In the disclosed embodiment, three mats are superimposed. The top and bottom mats are left uncompressed. An intermediate pulp mat is compressed and densied by embossing rolls prior to combining it with the top and bottom layers. This technique reduces the thickness of the ultimate pad, thus to make it easier to bend and fold the pad to tit body contour. Moreover, the compressed layer has increased capillarity, thus to promote lateral distribution of liuids outwardly from the pad center and toward its edges, thus to promote uniform absorption throughout the pad body.

The present invention is distinguished from certain prior art pads in which a wadding envelope is made from a single strip folded about one edge of the pad. In such pads, the edge folding subjects the wadding to tension, with undesirable stretching of the wadding. In the present invention, the wadding envelope is formed from separate upper and lower wadding strips which are power fed to eliminate pulling tension which might otherwise deform the strips. The upper and lower wadding strips are laid at against the upper and lower surfaces of the composite pad. The side and end margins of the strips which extend laterally beyond the pad filler are sealed in face relationship. This eliminates all edge folding and pulling stresses on the wadding.

The pad fillers are longitudinally spaced prior to encasement in the wadding envelope and the gaps between pad llers are sealed with cross seals, thus to form a ice continuous wadding tube with longitudinally spaced discrete wadding encased pad fillers connected by wadding links. The body contacting cover strip is then fed in face relation against one side of the continuously moving tube and has cross bands of hot melt adhesive printed thereon in registry with the links. The superimposed tube and body contacting cover strip p ass between a hot melt adhesive activating roll set which activates the adhesive and bonds the cover strip to the links. Thereafter, the links are severed through the bond to produce discrete pads with the characteristics hereinbefore described.

The pad in various appropriate sizes may be used as a hospital underpad, diaper, sanitary napkin, etc.

Other objects, features, and advantages of the invention will appear from the following disclosure.

DESCRIPTION OF DRAWINGS FIG. l is a somewhat diagrammatic side view showing transfer of the pulp mats from the forming screen onto the flexible conveyors and to a point in the fabrication of the pad slightly beyond where the wadding strips are introduced, this view being then rbroken olf and continued in FIG. 2.

FIG. 2 is a continuation of FIG. 1 showing further progress of the ensleeved pads. This view shows how the body contacting cover is applied and the ensleeved pad llers are severed into discrete pads.

FIG. 3 is an enlarged fragmentary plan view of a portion of FIG. 1 and showing the multiple pad mats stripped from the forming screen and overlapped by the horizontally exible conveyors.

FIG. 4 is a cross section taken along the line 4-4 of FIG. 3.

FIG. 5 is a somewhat enlarged side view showing the apparatus for conveying the pad tube through the hot melt reactivating rolls and the pad severing knives.

FIG. 6 is an enlarged fragmentary cross section taken along the line 6-6 of FIG. 2.

FIG. 7 is an enlarged fragmentary cross section taken along the line 7-7 of FIG. 2.

FIG. 8 is an enlarged view, partly in cross section, of the hot melt printing apparatus for the Ibody contacting cover strip.

FIG. 9 is a perspective view of the printing roll of FIG. 8.

FIG. 10 is a cross section taken along the line 10-10 of FIG. 5.

FIG. 11 s an inverted perspective View of a pad embodying the present invention.

FIG. l2 is a cross section taken along the line 12-12 of FIG. ll.

FIG. 13 is a diagrammatic plan view showing the orientation of the pads on the conveyor.

yDESCRIPTION `OF PREFERRED EMBODIMENT 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 structure. The scope of the invention is defined in the claims appended hereto.

In the embodiment illustrated, threepulp mats 20, 21, 22 are formed on aberizer 23 of the .general construction shown in U.S. Pat. 3,268,954 and are removed from the iiberizer on ascreen 24. As best shown in FIG. 3, therespective mats 20, 21, 22 are stripped from thescreen 24 ontobelt conveyors 25, 26, 27. These belt conveyors transfer the mats onto the intake ends of horizontallyexible conveyors 31, 32, 33. These conveyors are illustrated only diagrammatically in this application. Any suitable form of iexible conveyor can be used. See, for

example, the flexible conveyors shown in U.S. Pats. 2,872,023, 3,225,898 and 3,439,795, the disclosures of which are incorporated herein by reference.

Theflexible conveyor belts 31, 32, 33 are flexed horizontally as shown in FIG. 3 so that their discharge ends overlap vertically. Thus, the respective mat strips 20, 21, 22 are deposited one on top of the other on a takeoff conveyor 34.

It is au important feature of the present invention that theintermediate pulp mat 21 is passed between compression or embossing rolls 35, 36, thus to compress theintermediate mat 21 to less than about one-third of its normal thickness, thus densifying the intermediate mat to produce in the ultimate product an intermediate densied layer which promotes distribution of fluids laterally in the pad. Moreover, the compression of theintermediate pulp mat 21 reduces the over-all thickness of the pad, thus to facilitate bending and folding the pad to fit body contours. While in the disclosed embodiment compressed mat ply 21 is substantially coextensive in area with the uncompressed pulp plies 20, 22, it may be made smaller in one or both its length and width dimensions.

In corporated immediately on top of the intermediatecompressed mat 21 is a strip of wadding 37 taken from aparent roll 38. TheWadding strip 37 is fed beneath thecompression roller 35 and occupies a position in the pad as shown in FIG. 12.

Top mat 20 is led down bybelt conveyor 30, andbottom mat 22 is led up by conveyor 34 to their intersection where all mats join and are fed beneath cooperating overlying conveyor 40 to a pulp filler cutoff roller 41 and its underlying platen roller 42. Rollers 41, 42 cut the mats into discretepulp pad llers 43 which continue on into the apparatus best shown in FIG. 2.

Thediscrete pulp llers 43 are conveyed between anupper conveyor belt 44 and a lower conveyor belt 45.Belts 44, 45 run at a slightly faster speed than the belts 34, 40, thus to produce gaps 46 between successive llers. The pulp llers are further enclosed within a wadding tube orenvelope 39 comprising anupper Wadding strip 47 and alower wadding strip 48 which respectively unwind from parent rolls 51, 52.

Strips 47, 48 are slightly wider than thepulp filler 43. Thus, their side margins are crimped together at 58 by the crimpingrolls 53 shown in FIG. 6. Edge waste is cutoli by the combination of aknife roll 54 and aplaten roll 55, as shown in FIG. 7. In this manner thelillers 43 are entubed in a generallyflat wadding envelope 39 which consists of two strips of wadding laminated in face relation at the edges of the tube.

Beyond thebelts 44, 45 therespective fillers 43 are sealed in theenvelope 39 crossways by thecross crimping roller 56 which cooperates with its platen roller 57, thus to produce cross sealedbands 59 sealing eachpad filler 43 within thetube 39.

Thetube 39 then passes throughconveyor belts 73, 74, where a body contacting cover strip 60 is assembled in face relation to the underside of the envelope. Strip 60 desirably consists of smooth, soft, non-Woven fabric unwound from a parent roll 61. The strip 60 has periodically printed upon it a cross band or stripe 62 (FIG. 8) of hot melt adhesive, applied thereto by printing roll 64 in the hot melt adhesive tank 63. Printing roll 64 is immersed in a molten adhesive bath 65. The printing roll 64 has embedded in its periphery intaglio printing bars 69 which have dimpled surfaces 66 to retain adhesive picked up in the bath 65. A doctor blade 67 scrapes from the periphery of the roll 64 all of the hot adhesive, except such as is retained beneath its surface in the dimples 66.

The cover strip 60 is narrower than the envelope 39 (FIG. 11) and is fed at a lineal speed equal to the peripheral speed of the printing roll 64 and across the roller guides 68 mounted on a carriage 71 on the retractable piston and cylinder assembly 72. The cover strip 60 is fed at the same speed asfeed belts 73, 74. The printing bars 69 on roller 64 are spaced peripherally a distance exactly equaling the intergap spaces intube 39. Thus, the printed cross stripes orbands 62 register with the tube gaps.

The hot meltadhesive cross bands 62 cool and solidify in the course of traveling through the apparatus until they reach an adhesive activating roll set consisting of a heated roll 75 and a platen roll 76. There are a series of heating bars 77 on the roll 75. Bars 77 coact with thetube 39 in the gaps between successive pads so as to activate thebands 62 and cause the body contacting cover strip 60 to adhere to the previously crimped cross bands on the tube. As the tube leaves the cross band activator 75, the links 78 between successive pads in thetube 39 will be gripped by the grippingbars 80 on the upper and lower chain feeders 81 (FIG. 5). Thebars 80 cool and set the activatedadhesive bands 62. Feeders 81 transfer thetube 39 to the linal cutoff station which includes knife roll A82 andplaten roll 83. Therolls 82, 83 are intermediate the ends ofconveyor chains 84, 85 which have pad gripping bars 86.Bars 86 are so positioned as to grip the pads, as shown in FIG. 5, thus leaving the links 78 between the pads exposed to be cut olf as they pass between the knife roller `82 andplaten roller 83. The nal severedpad product 90 is then removed on a conveyor 91. FIG. 13 illustrates the fact that thepads 90 are formed with their longest dimension transverse to the direction of advance oftube 39 through the machine.

The final pad product is shown in FIGS. 11 and l2 (inverted as compared to previous views). As is clear from FIG. 11, the body contacting cover strip 60 is not as long as the pad, thus to leave the end margins of the pad uncovered. Moreover, the strip 60 is applied to only one face of the pad. This construction is particularly advantageous Where thepad 90 is used as a diaper and the diaper is folded about the baby. Accordingly, the body contacting cover 60 is located only over the central portion of the diaper which becomes soiled and wet, thus to prevent pilling of the pulp and wadding in that affected area. A substantial saving is thus made in the amount of cover material needed for each pad.

An important feature of the present invention is the method and apparatus by which undue stresses on the wadding strips 37, 47, 48 are avoided. In the Iirst place, the wadding strips are not folded around the edges of the pads as in some prior art pads. Such folding produces tension in the wadding, thus tending to stretch the Wadding and possibly pull it out of shape or tear it. In the present apparatus and method, the wadding strips are simply laid in parallel superimposed relation. The edge margins ofstrips 47, 48 are overlapped and crimped, as shown in FIG. 6. This avoids any necessity for stretching or imposing pressure on the wadding as would other- Wise be required if it were folded or pulled around the edges of the pad.

Moreover, each Wadding strip is relieved of the necessity for pulling it from the parent rolls 38, 51, 52. This is accomplished by providing each parent roll with apowered belt driver 92. Thebelt drivers 92 drive the parent rolls so as to unwind the strips under power, and relieve the strips of tension which would otherwise be induced in the strips. Accordingly, for this additional reason, the wadding strips are not stretched or otherwise distorted in the course of formation of the tube in which the pad llers are encased.

The completed pad, as shown in FIGS. ll and l2, contains amid layer 21 of compressed pulp and outside layers 20, 22 of uncompressed pulp. Thecompressed layer 21 promotes rapid lateral ilow of fluids, thus to promote uniform absorption of fluid in all of the pulp material in the pad.

I claim:

1. In an absorptive pad having a pulp ller, an absorbent wedding envelope and an absorbent body contacting cover outside the envelope, the improvement in which said body contacting cover is at one side of the pad only, is shorter than the pad is long, and is disposed at the center of said one side of the pad to leave absorbent end margins of the pad uncovered, said wadding envelope comprising two wadding plies having peripheral margins in face relation, said body contacting cover having side margins attached in face relation to portions of the peripheral margins of the wadding plies.

2. The pad ofclaim 1 in which the side margins of the body contacting cover are attached to portions of the peripheral margins of one of the wadding plies by stripes of hot melt adhesive.

3. The pad ofclaim 1 in which the pulp ller includes at least one layer of substantially uncompressed pulp 15 mat and another layer of compressed pulp mat.

4. The pad ofclaim 1 in which the peripheral margins of the wadding envelope are held together by crimps.

References Cited UNITED STATES PATENTS 2,890,700 6/ 1959 Lonberg-Holm 128-284 3,424,163 1/ 1969 Gravdahl 128-290 2,787,271 4/ 1957 Clark 12'8--290 2,682,873 7/ 1954 Evans et al 128-296 X 3,294,090 12/ 1966 Younger 128-290 3,315,676 4/1967 Cooper 161-151X 10 3,344,789 10/ 1967 Arnold et al 128-287 FOREIGN PATENTS 269,399 4/ 1927 Great Britain 128-296 WILLIAM A. POWELL, Primary Examiner U.S. Cl. X.R.

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