US3254374A - Manufacture of cellulosic products - Google Patents

Description

June 7, 1966 GREINER ET AL 3,254,374

MANUFACTURE OF CELLULOSIC PRODUCTS Filed April 18. 1960 7 Sheets-Sheet 1 June 7, 1966 c. J. GREINER ET A. 3,254,374

MANUFACTURE OF CELLULOSIC PRODUCTS '7 Sheets-Sheet 2 Filed April 18. 1960 June 7, 1966 C,J, GRElNER ET AL 3,254,374

MANUFACTURE OF CELLULOSIC PRODUCTS Filed April 18. 1960 7 Sheets-Sheet L5 June 7, 1966 c-.J.eRI-:lNER E AL ,2 4,

IANUFACTURE 0F CELLULOSIC PRODUCTS I Filed April 18. 1960 7 Sheets-Sheet 4 June 7, 1966 c. J. GREINER ET AL MANUFACTURE OF CELLULOSIG PRODUCTS 7 Sheets-Sheet 5 Filed April 18. 1960 .wmv QM w June 7, 1966 c. J. GREINER ET AL 3,254,374

MANUFACTURE OF CELLULOSIC PRODUCTS '7 Sheets-Sheet 6 Filed April 18. 1960 June 7, 1965 c. J. GREINER ET AL 3,254,374

MANUFACTURE OF CELLULOSIC PRODUCTS 7 Sheets-Sheet 7 Filed April 18. 1960 United States Patent MANUFACTURE OF CELLULOSIC PRODUCTS Charles J. Greiner, Menasha, and Henry R. Cloots and Harold V. Rutkus, Neenah, Wis., assignors to Kimberly-Clark Corporation, Neenah, Wis., a corporation of Delaware Filed Apr. 18, 1960, Ser. No. 22 ,875

13 Claims. (Cl. 19145) This invention relates generally to an improved method of fabricating absorbent bandages; to improvements in apparatus for the high speed production thereof; and to improvements in the resulting product. The invention is particularly applicable to the'pleating of the tab portions of a sanitary napkin wrapper extending beyond opposite ends of the enclosed absorbent pad for attachment to belts or undergarments during use.

A major object of the invention is to provide an improved method of pleating sanitary napkin tab ends during the fabrication thereof on high speed production apparatus. 7

An equally important object is to provide an improved method of fabricating sanitary napkins with outwardly tapering and marginally pleated tab end portions symmetrically reduced to narrow the width of the tab ends in respect to the pad width in a manner to increase pin strength while facilitating attachment to belts and the like.

An additional object is to provide improvements in apparatus incorporating the concepts herein taught for the high speed production of sanitary napkins having neatly tailored tapered tab ends marginally overpleated in a symmetrical manner to facilitate threading through supporting belts.

Still another object is to provide improved apparatus for the high speed production of wrapper enclosed absorbent bandages, such as sanitary napkins having tapered tab ends formed of certain materials desirable for such end use but which exhibit certain undesirable machine characteristics during processing on equipment designed for the high speed inpleating of tab ends. The present invention thus permits the use of a much wider range of wrapper materials than does the conventional inpleating method.

A further object is to provide an improved sanitary the same reference numeral,

FIG. 1 illustrates in perspective a portion of a sanitary napkin a tab end of which incorporates the invention,

FIG. 2 illustrates in perspective a sanitary napkin having both tab ends pleated in accordance with the invention,

FIG. 3 is an end view showing the doubly pleated tab end of FIG. 2 greatly enlarged,

FIG. 4 illustrates in perspective one stage of the method of the invention, I

FIG. 5 is similar to FIG. 4 but shows an advanced stage of Web pleating,

FIG. 5a illustrates in perspective the feeding and delivery arrangement,

FIG. 6 shows in plan the constructional details of the web forming and pleating apparatus as partially shown in FIGS. 4 and 5,

FIG. 7 shows in side elevation the apparatus of FIG. 6,

FIG. 8 is an enlarged fragmentary elevation taken along wrapper between successive pads during passage through a constricting nip but prior to being shaped by pleat forming tuckers,

FIG. 14 shows the change in wrapper configuration at the upstream end of the tuckers,

FIG. 15 illustrates the wrapper configuration at the downstream end of the tuckers, and 1 FIG. 16 is a plan view of the pleating ramp shown in perspective in FIG. 11.

While it is known to taper outwardly as well as to marginally pleat sanitary napkin wrapper tab ends, substantial problems are involved in the operation of high speed apparatus designed to introduce both the desired degree of taper and to effect consistently uniform known types 'of marginal pleats. Simple over-pleating such as a diagonal fold-over of the tab end portions from a position adjacent the absorbent pad along an oblique line of taper outwardly of the pad does not utilize the full potential of available pin strength. Serious production difiiculties are presented in obtaining such folded over pleats in the tubular tensioned wrapper material between similarly spaced pads without slitting the material, a step which has proved impractical at high mass production speeds. Marginal infolds of moderate depth symmetricallyformed between the outer plies of tab ends and accompanied by some transverse tapering of the tab ends are rather Widely employed, although manufacturing difliculties encountered at high production speeds such as maintaining proper alignment and configuration of the wrapper material commonly result in non-uniformity of folds, hence either a high rejection rate or a lowering of tolerance standards. The method and apparatus herein described permits the high speed production of improved fibers. Manufacturers seek constantly to improvet-heir wrapper materials in respect to appearance and softness, tensile strength, fluid permeability and pin strength, while maintaining manufacturing costs at acceptable competitive levels. Since improved wrapper materials often vary as to physical, hence processing, characteristics it is of major importance that production equipment be capable of satisfactorily processing a wide range of wrapper materials without requiring modification or re-design thereof. The present invention permits satisfactory process-.

ing of a wide range of such material by avoiding the necessity of subjecting the material to high stresses during pleat formation. The required web displacement, meaning the extent to which any discrete area of the wrapper must be moved during formation of pleated tab ends is configuration.

a substantially lowered, as compared to inpleating, by the method and apparatus herein taught. The term web is used alternately herein with wrapper and wrapper materia to mean any of the above mentioned materials or modifications thereof.

Satisfactory inpleating such as by the apparatus taught in co-pending Pukis and Rutkus US. application 725,108, filed March 31, 1958, now Patent No. 3,020,599, and assigned to applicants assignee requires accurate alignment of the web in the machine and rather exacting continuous maintenance of all machine adjustments. Improperly pleated tab ends, such as those with the web margin extending laterally of a pleated margin frequently result from improper machine maintenance. The web must be sufiiciently stressed to maintain a transverse configuration between pads roughly that of the corresponding pad Also, the inpleating blades have a tendency to pass either over or under a lightly stressed web instead of forming a pleat. Such initially required wrapper tension is substantially increased as the blades employed in inpleating force the side-(wall wrapper material inwardly between the tab forming outer plies to an extent much greater, as above mentioned, than is required by the overpleating method of the present invention. Inpleated portions of the wrapper material, thus necessarily placed under high stresses during formation, are therefore substantially biased toward lateral expansion as they leave the folding blades and prior to passage through closely positioned ironing rolls which fix the pleats.

While it is conventional practice to iron infolded pleats after forming, structural limitations dictate the necessity of spacing the ironing rolls at least a short distance from the pleating blades. The type of pleating herein taught is easily effected without the necessity of subjecting the wrapper material to the above mentioned stresses, hence there is no appreciable change in web configuration between the final forming steps and ironing. For the above reasons, many materials which do not take an acceptable inplcat either because they do not keep in proper machine alignment or because they will not hold their pleats prior to ironing are easily over-pleated in accordance with this invention.

FIGS. 1 and 2 illustrate a sanitary napkin comprising a pad portion 48 enclosed in a fluid pervious wrapper 12 having portions extending beyond the opposite ends of pad 48 to form tab ends 14 and 16 which may be of equal or unequal length. Tab end 14 is shown marginally over-pleated at 18 and 20 in accordance with the invention. As shown in the enlarged end view of FIG. 3, a portion of the wrapper material is marginally folded over the upper overlapping ply 34 of tab end 14 with a like portion folded over the lower ply of the central portion of 14. The marginal folds 18 and 20 preferably start at a position slightly outwardly of the ends of pad 48 and increase in depth along convergent fold lines extending toward the end of each tab portion until the desired tab end width is obtained. The fold lines may be linear or slightly arcuate to provide the neatly tapered tab end configuration illustrated. Such a taper may extend continuously to the end of the tab end or may lead to portions of uniform width as shown.

As shown in the enlarged end view of FIG. 3, the present method converts the generally rectangular configuration which the wrapper defines transversely of each pad into tab end configurations defining double pleats {l8 and '20 formed by overfolding rather than infolding marginal portions of the wrapper material. The production difficulties mentioned as inherent in the accordion-type infolding method are thus avoided. Both the inner and outer plies of the double pleats '18 and 20 are of inwardly open and outwardly closed U-config-uration as distinguished from the inwardly closed and outwardly open pleats of V-configuration obtained by the inpleating method. Double marginal pleat 18 comprises a marginally closed outer ply portion forming the exposed portions of the upper and lower double pleats, the inner margins of which are reversed at 22 and 24 to form within the area of the exposed pleat portions two additionally outwardly closed -U-configurations as the outwardly extending inner ply portions 26 are reversed to form the closed end of the inwardly defined Us, the inner leg portions 28 of which are integral extensions of the bottom ply 30 and the overlapped upper tab end ply-34, respectively. While the marginal pleats shown in FIG. 3 are formed in a manner to position one side margin 36 of the wrapper material inwardly of double pleat 18 and to position the other side margin 38 thereof inwardly of the opposite double ply 20, the formation of somewhat wider over-folded marginal pleats, as below described, may result in the positioning of wrapper margins 36 and 38, respectively, well inside the double pleats 18 and 20, but still positioned between the lower tab pleat 30 and the upper overlapped tab pleat 34. In some instances, however, with very wide and substantially abutting marginal pleats thus formed, the wrapper margins 36 and 38 may extend completely through the double pleats 18 and 20 and partially around either of the two innermost portions of U-configuration to terminate, for example, between one of the pleat portions 26 and the outermost pleat portion contiguous thereto. The constructional advantages of the improved tab ends are later explained.

The apparatus illustrated in perspective in FIGS. 4 and 5, the detailed construction of which is shown in other figures, comprises a framework shown at 40, FIG. 8, along which a tunnel-like wrapper guide 42 of inverted U-configuration extends in a linear path. A beltlike conveyor 44 immediately below guide 42 and forming a bottom closure for the guide continuously moves an elongate wrapper-forming web 46 which is fed from a supply roll 47, shown in FIG. 5a, onto belt conveyor 44. Absorbent pads 48 are sequentially fed in evenly spaced relation down chute 35 onto conveyor carried web 46 from a suitable supply source, the web 46 moving at a uniform speed toward the left as shown as folding ramps 50 and 52, associated with guide 42, progressively overfold the web about pads 48 into a tubular configuration overlapped along the tops of the pads, the margins of the overlapped web portion being shown at 38.

FIGURE 5a also illustrates in perspective the feeding and delivering arrangement. As shown in the drawing, wrapper forming web 46 is continuously fed from supply roll 47 onto moving conveyor belt 44. Conveyor belt 44 is driven by roll 45 and passes over guide rolls 37 and 39. The latter r-olls urge belt 44 in sliding engagement with the underside of horizontal frame member 40 to provide, in combination with top guide member 42, a forming chamber for moving web 46. Absorbent pad elements 48 are fed from chute 35 onto belt-supported web 46 at regularly spaced intervals, as web 46 moves from right to left. Web 46, carrying spaced pads 48, then passes through vertical frame member 41, which has mounted on the front portion thereof a presser foot 43. As the pads 48 pass under foot 43, they are firmly pressed into non-sliding engagement with web 46 and move along with web 46 as the side edges of the web are progressively folded over the pads 48 by folding ramps 50 and 52, as previously described, to form a tubular configuration of substantially the transverse perimeter of the enclosed pads. The web 46, enfolding spaced pads 48 in said tubular configuration, is then marginally pleated in the area between pads by operation of elements shown generally at 63 and 68. As subsequently described in more detail, element 63 vertically depresses the central portions of the tube to provided an I-beam configuration, while element 68 moves inwardly in a horizontal plane to fold inwardly the crossbars of the I-beam configura tion. The marginally formed pleats are pressed flat by heated ironer rolls 71 and 73. The web-enwrapped pad, and the pressed and pleated wrapper then continue on through driven rolls 51 and 53 which serve to maintain forward tension on the assembly as it moves through the operation. As shown in the drawing, rolls 51 and 53 have mated surfaces, with reduced-radii portions 55 and 57 having a circumferential arc of a length corresponding .to the length of the napkin body portions 48, and the raised surface portions 59 and 61 having a circumferential arc of a length corresponding to the length of the pressed wrapper in the space between successive napkin bodies. Rollers 51 and 53 operate at a nip pressure sufiicient to maintain the web under tension to retain the tubular configuration previously described. The pleated wrapper is subsequently severed transversely to provide individual sanitary napkin units.

The illustrated method of continuously enclosing spaced absoribent pads in a wrapper material is known, the prese'nt invention being directed. .to the formation of the portions of the wrapper material between successive pads into improved marginally pleated tab ends. Web folding is completed before conveyor belt 44 leaves its linear path during passage about its forward drive pulley 54, at which position the elongate assembly of web enclosed pads is fed onto an adjacent elevating ramp 56 having an obliquely depressed receiving end 58 marginally of a horizontal portion 60 leading into a narrowed inclined portion 62 'which in turn leads upwardly to an elevated shelf-like portion 64. Ramp 56 serves the function of momentarily supporting the lower mid-portion of the pad enclosing web while elevating that portion in respect to outer unsupported portions thereof as the mid-portion passes through a contour changing constriction nip 66 formed between the inclined ramp portion 62 and a constricting shoe 63 intermittently positioned in spaced relation to and above the ramp, transversely to reshape the tubular web from the substantially rectangular pad defined shape as shown in FIG. 12 into the substantially I-beam configuration shown in FIG. 13.

The improved method of marginally forming the symmetrically paired overpleats of the invention is clearly illustrated in FIGS. 4, 5, and 5a. Since pads 48 and the web guide 42 are both transversely rectangular, those web portions between the pads assume a like configuration, it being understood that the web is subjected continuously to suflicient forward tension, by pressing roll 71 and 73 and by drawing rolls 51 and 53, to hold that configuration until re-shaping as below described. As a wrapper enclosed pad 48 is drawn from conveyor 44 and over ramp 56 the web bridges that pad and a trailing pad while being maintained under suflicient tension continuously to stress the web into tubular configuration. With a pad 48 in the position shown inFIG. 5, the web constricting shoe 63 is in .a retracted position above the path of web travel, and a pair of marginal tuckers 68 are also in positions of retraction laterally-f the web path. As later described, shoe 63 and tuckers 68 move into the path of web travel in synchronously timed relation to the rate of pad movement through the respective path of movement of intermittently operable members 63 and 68. As the trailing end of pad 48 clears the curved lower end 70 of shoe 63, the shoe is rapidly cammed down to position the end 70 thereof in nipforming spaced relation to a narrowed portion 62 of ramp 56, a plan view of ramp 56 being shown in FIG.

16. The nip-forming portions of the shoe and ramp are of substantially equal width. The resulting elongate nip 66 vertically narrows down amid-portion of the web perimeter to change the shape thereof from the generally rectangular transverse configuration shown in FIG. 12 to the somewhat I-beam configuration of FIG. 13. Momentarily thereafter, a pair of tuckers 68 move from the positions of FIG. into the web contacting positions of FIGS. 4 and 14 to re-shape the web from the FIG. 13 into the FIG. 14 configuration.

As best shown in FIG. 11, tuckers 68 include a pivotally mounted arm the free end of which carries an inwardly opening U-shaped channel member 74, flared as a guide at its upstream end 76 and vertically tapering downstream from the transverse configuration of FIG. 14 to the vertically reduced configuration shown at the downstream end 78. Movement of the web through tuckers 68 thus effects progressive marginal fold-over of the web as best shown in FIG. 15. Both shoe 63 and tuckers 68 remain in the pleat forming FIG. 11 position until withdrawn to retracted positions momentarily prior to the arrival of a trailing pad, such retraction being necessary to prevent interference with the spaced pads. As best shown in FIGS. 11, 15, and 16, side marginal areas of ramp portions 62 and 64 are reduced in thickness in respect to the central portion thereof. Those ramp areas provide support for marginal areas of the web during pleat forming. Such reduction permits the tab center plies and top pleat to move through the channels .of tuckers 68 above the ramp with the bottom pleat moving therethrough beneath the ramp with the tucker channels tapered to the desired extent which is difficult with thicker ramp margins. After substantially simultaneous passage of the pleated web beyond the elevated ramp shelf 64 and through the tuckers 68, that pleat previously below the ramp moves upwardly. toward its adjacent tab end underply to be ironed into symmetry with the upper pleat as below described.

' Upon leaving the trailing ends 78 of tucker channel members 74, the marginally folded web passes in the configuration shown in FIG. 15 between a pair of heated ironing rolls 71 and 73, as closely spaced downstream as the structure permits. Rolls 71 and 73 are fixedly mounted on journalled shafts 79 and 81, respectively, those shafts being driven in counter-rotation by-mechanical connection to a main drive shaft 92, as indicated by the dotted lines 91. Rolls 71 and 73' are provided with flats and 77. The flats relieve minor portions of the roll diameter, for example about 160 thereof, to allow passage, as the flats move into registry, of the web enclosed pads therebetween at the end of the ironing stage.

Structural details of the mechanism which operates the constricting shoe 63, tuckers 68 and the ironing rolls 71 and 73 in the manner shown in FIGS. 4 and 5 are shown in FIGS. 6 toll inclusive. As best shown in FIGS. 6 to 8, constricting shoe 63 is attached to a pivot arm 98 fixed to extend radially from one end of a rock shaft 100 journalled in a bearing assembly 102 to extend transversely of the'pat-h of web travel, assembly 102 being supported by framework 40. The opposite end of shaft 100 carries a cam follower arm 104 provided with a roller 106 with arm 104 biased-by spring 108 into engaging contact with a cam plate 110 mounted on the main drive shaft 92 to synchronize actuation of the constricting shoe with actuation of the tucker mechanism.

Tuckers 68 and extension members 82 are fixed to pivotally mounted arms 80 which are reciprocally cam driven between the dotted and full line positions shown in FIG. 6 by a pair of cup cams 88. As shown in FIG. 9, cams 88 are fixed to and drivenby shaft 92, journalled at 90. Cam followers 86 affixed;to arms 80, are maintained engaged with earns 88 by a retraction spring 89 extending under tension between the arms.

. As best shown in FIG. 10, arms 80 are mounted to pivot about bearings 84 mounted in a supporting assembl 85. Cup cams 88 are spaced on the drive shaft 92 to permit conveyor pulley 54 to be rotatably mounted therebe-' between shoe 63 and tuckers 68 is obtained both by proper design of the cam contour and by its circumferentially fixed position on shaft 92 in respect to cams 88. That position may, if desired, be adjusted by a suitable shaft locking device, not shown. As above mentioned, a drive connection illustrated by phantom lines 91 causes ironing rolls 71 and 73 to be driven by shaft 92 in synchronism with the reciprocation of tuckers 68 through cup cams 88 and with the actuating of constricting shoe 63. The linear speed of the conveyor 44 is suitably synchronized with the rotational speed of drive shaft 92 in a known manner from the common source of power, such connection not being shown.

To prevent the web from being burned between the hot rolls 71 and 73 following shut-down of the machine, constriction shoe 63 is automatically raised by a known protective circuit associated with a retracting piston unit 112 and the hot rolls 71 and 73 are simultaneously spaced apart by a similar unit 114. The circuit renders units 112 and 114 operable during machine stoppage and inoperable during operation thereof.

As is evident from the above description of the method and apparatus, the width of the resulting over-folded pleats may be varied by altering the width of both the ramp portion 62 and portion 70' of the nip-forming shoe 63 in respect to the perimeter of the tubular web, the extent of longitudinal web overlap not being a controlling factor. Sanitary napkins currently produced by applicants assignee and sold under the trademark Kotex are of a pad size defining a web perimeter during fabrication of about 6%". Factors inherent in the bellows type inpleating method such as the required displacement of the web while substantially tensioned and the resulting stresses limit tab ends formed from a similar tube to a width of about 1%". However, with the present over-pleating method, the pleats may, as above mentioned, be formed wider than shown in FIGS. 1 and 2. For example, pleats may be formed of sulficient width to bring the inner margins of the pleats substantially into abutment. The provision of such pleats reduces the width of the tab ends formed from a tubular web of 6% perimeter to about 1%. The resulting narrowed tab ends are more easily looped through belts,

hence may be preferred by some users.

Referring particularly to FIG. 3, it is evident that proper pinning of the tab ends shown results in a pin strength greater than is obtained by pinning a tab end having either C-folded pleats or a tab end provided marginally with pleats of inwardly directed V configura tion. The fastening pin normally pierces only four web thicknessesin the area of each pleated margin, whether C-folded or inpleated in outwardly open V configuration, while piercing six web thicknesses in the area of each tab end margin pleated in the manner herein taught.

It is thus seen that the invention offers a very wide degree of flexibility in respect to the formation of outwardly closed over-folded and symmetrically paired marginal tab end pleats. Sanitary napkins may be so pleated with relative ease at high production speed and offer many advantages during use.

We claim:

1. The method of symmetrically double pleating the margins of sanitary napkin tab ends comprising the steps of forming an elongate continuously moving assembly of wrapper enclosed spaced pads while maintaining the wrapper tensioned between the pads, momentarily shaping wrapper portions between successive pads substantially into I-beam configuration transversely across the width of the assembly, folding inwardly wrapper portions forming the ends of the I-beam configuration into symmetrically disposed U-configurations which are inwardly open and outwardly closed, and thereafter pressing said folded back portions into contacting engagement with contiguous marginal portions of the tab ends whereby the marginal edges of said tab ends are provided with six thicknesses of wrapper material.

2. The improved method of pleating the tab ends of absorbent bandages in which an assembly of like elongate pads in end to end spaced relation are enclosed within a continuously moving enclosing wrapper while subjecting the wrapper to suflicient tension to maintain between the pads a tubular configuration of substantially the transverse perimeter of the enclosed pads, said improvement comprising intermittently subjecting a central portion of the width of said tubular wrapper material between successive pads to suflicient transverse constriction substantially' to narrow the configuration of said central portion in respect to outer non-constricted portions, shaping and inwardly folding the outer non-constricted wrapper portions in a manner to form a pair of symmetrical inwardly extending marginal pleats with one pleat of each pair disposed on each side of the constricted portion of the wrapper to provide the edges of the wrapper in the area between pads with six thicknesses of material, and thereafter subjecting the marginally folded wrapper to heat and pressure to iron the portions thus pleated into substantially planiform configuration.

3. The method of claim 2 wherein the shaping of the non-constricted marginal portions of the wrapper is effected by causing those wrapper portions continuously to pass through marginal tuckers of progressively narrowing configuration.

4. The method of making sanitary napkins comprising enclosing a plurality of absorbent pads within an elongated wrapper of liquid pervious foldable material, tensioning the wrapper sufficiently to maintain those portions between the pads in substantially the cross-sectional configuration of the pads, moving the wrapper and enclosed pads at uniform speed along the longitudinal axis of the plural pad assembly, subjecting a central portion of said wrapper during its movement past a station fixed in respect to the path of movement to a constricting nip extending transversely of the direction of Wrapper travel and of lesser width than that of the pads, momentarily to establish a generally I-beam configuration transversely of the Wrapper, and thereafter folding inwardly portions of the material forming each end of the -I-beam configuration toward the centrally constricted wrapper portion to obtain a symmetrically disposed pair of U-configurations which are inwardly open and outwardly closed to provide the edges .of the wrapper portion between pads with six thicknesses of material, and thereafter feeding the folded wrapper between heated pressure rolls to iron the symmetrically disposed portions against the central wrapper portion.

5. Apparatus of the character described having in combination, means for forming a continuously moving assembly of spaced pads enclosed in an elongate wrapper, means maintaining the wrapper sufiiciently tensioned to insure a tubular configuration between the pads of substantially the transverse perimeter of the pads, means for intermittently shaping the transverse wrapper perimeter between successive pads into an I-beam configuration, means closely spaced downstream from said first means for re-forming end portions of said I-beam configuration into symmetrically disposed U-configurations, and means downstream from the last mentioned means for flattening the wrapper from said symmetrically disposed U-configurations into a multi-ply tab end with the said symmetrically disposed portions flattened into integral overpleats extending marginally along each face of the tab end thus formed.

6. In apparatus (for the pleating of pad wrapper tab ends, the combination with means for continuously enclosing a plurality of spaced pads within an elongate foldable wrapper, means for moving the pad enclosing wrapper at a constant speed while maintained bridged in tubular configuration between the pads, means for intermittently forming a nip extending transversely of and of less width than the transverse wrapper dimension for passage therethrough of a central portion of the tubular wrapper to re-form the transverse configuration thereof in the area between pads into a generally I-beam shape, intermittently operable means spaced adjacent said nip in the direction of wrapper travel for the progressively increased over-folding of the material forming end portions of the 'I-beam configuration, and means for thereafter pressing the wrapper material into fiat tab ends between pads with the over-folded wrapper portions flattened into symmetrical pleats on opposite sides of and extending along the margins of the tab end.

7. Apparatus of the character described comprising means for continuously moving a plurality of spaced pads, means for encircling said pads with a continuously moving Wrapper material, means maintaining the wrapper tensioned to bridge consecutive pads in tubular configuration, means intermittently operative in the time interval of movement of successively spaced and wrapper pads thereby vertically constricting the central area of the pad bridging wrapper portions between pads along a path disposed transversely of and narrower than the path of wrapper travel, means for shaping the non-constricted portions of the tubular wrapper between pads into progressively narrowing inwardly directed substantially U configurations, and means for ironing the configuration thus formed into multiple ply tab ends with the U portions of the wrapper material flattened to form symmetrical pleats on opposite sides of marginal areas of a tab end thus formed.

8. Apparatus for the manufacture of sanitary napkins from a web of foldable wrapper material continuously fed thereto and a succession of absorbent pads fed in spaced relation onto said web, means for successive over- -folding of marginal portions of the Web to form a tube enclosing the pads and bridging the spaces therebetween, means longitudinally tensioning the wrapper to maintain the pad bridging portions in tubular configuration, means movable t and from the path of wrapper travel and positioned downstream from the tube forming means and adapted intermittently to re-shape the tubular wrapper between pads into substantially a transverse I-beam configuration, second re-shaping means downstream of the first re-shaping means and movable to and from the path of wrapper travel for changing said transverse I-beam configuration into symmetrically disposed U-configurations which are inwardly open and outwardly closed, and means downstream from said second re-shaping means for flattening the inwardly disposed portions of said U-configurations against adjacent web portions to provide a pair of symmetric marginal over-pleats.

9. The apparatus of claim 8 wherein the means forming the I-beam wrapper configuration comprises a member fixed in and'extcnding transversely of the path of wrapper travel for the support of the lower central portion of the wrapper tube, a constricting shoe of substantially the transverse width of said fixed member mounted for movement between a retracted position above to a position within the path of pad travel, said shoe when in the latter position being spaced above said fixed member at a distance to constrict a central portion of the tube momentarily to establish said transverse I-beam configuration.

10. The apparatus of claim 8 wherein the re-shaping means forming the symmetrically disposed U-configurations comprises a pair of marginal tuckers mounted and synchronously connected for movement from retracted positions laterally of the path of tube travel to a position of engagement with those portions of the formed wrapper tube immediately upstream thereof into the ends of the I-beam configuration, said tuckers being of someing in a downstream direction with the sides thereof opentuckers serve a funnel-like function to over-fold portions of the web forming the ends of the I-beam configuration to effect symmetrically disposed U-configurations which are inwardly open and outwardly closed.

11. The apparatus of claim 9 including means for the actuation of both said first and second re-shaping means in timed relation to the spaced positions of the web drawn pads, means for actuating said constricting shoe from a retracted to a nip forming position momentarily after passage of a pad past the path of shoe travel and for retracting said shoe momentarily prior to movement of a trailing pad into that path.

12. The apparatus of claim 10 including means timed in respect to the spacing of said pads for the actuation of said tuckers from retracted to web engaging positions momentarily following passage of a pad through the paths of movement thereof and retraction from said Web engaging positions momentarily prior to the passage of a trailing pad through said paths of movement.

13. In apparatus of the type described, a conveyor driven at uniform speed and having a downstream end defined by a support pulley, means feeding a continuous web material to said conveyor, means feeding uniformly spaced pads onto the web, means folding the web in tubular configuration over the pads, means maintaining the Web tensioned to retain tubular configuration of the pad bridging web portions, a ramp in close proximity to said pulley and extending upwardly of the conveyor path, a portion of the ramp being narrower than the width of the pads and positioned symmetrically of their path of travel, means downstream of the conveyor for drawing the web and enclosed pads over the ramp with the web maintained tensioned, a web-constricting member mounted for movement from a position above the path of pad movement over the ramp to a position above the ramp within the path of pad movement, said member extending transversely of the pad path in substantial registry with said narrow ramp portion and spaced, when in said path, sufliciently above the ramp to form a constricting nip therebetween for transverse re-shaping of the web perimeter in the area between pads into a generally I-beam configuration, means intermittently operable from positions laterally of the path of pad travel to positions of engagement with the outer non-restricted web portions progressively to re-shape the web perimeter into symmetrically disposed U-configurations which are inwardly open and outwardly closed, and means timing the actuation of said nip-forming member and said subsequent re-shaping means in respect to the rate at which the spaced pads travel over the ramp.

References Cited by the Examiner DONALD W. PARKER, Primary Examiner.

HAROLD B. WHITMORE, Examiner.

C. F. ROSENBAUM, Assistant Examiner.

Claims (1)

1. THE METHOD OF SYMMETRICALLY DOUBLE PLEATING THE MARGINS OF SANITARY NAPKIN TAB ENDS COMPRISING THE STEPS OF FORMING AN ELONGATE CONTINUOUSLY MOVING ASSEMBLY OF WRAPPER ENCLOSED SPACED PADS WHILE MAINTAINING THE WRAPPER TENSIONED BETWEEN THE PADS, MOMENTARILY SHAPING WRAPPER PORTIONS BETWEEN SUCCESSIVE PADS SUBSTANTIALLY INTO I-BEAM CONFIGURATION TRANSVERSELY ACROSS THE WIDTH OF THE ASSEMBLY, FOLDING INWARDLY WRAPPER PORTIONS FORMING THE ENDS OF THE I-BEAM CONFIGURATION INTO SYMMETRICALLY

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