US 2926394 A
Description (OCR text may contain errors)
J. c. BLETZINGER Erm. 2,926,394
METHOD FOR MAKING A CELLULOSIC PRODUCT Filed April 13, 195e.
March 1, 1960 3 Sheets-Sheet l March l, 1960 1 J. c. BLETZINGER ErAL 2,925,394
METHOD Foa MAKING A cELLuLosIc PRonUcT Filed April 13. 1956 3 Sheets-Sheet 2 March 1, 1960 J. c. BLETZINGER ETAL 2,926,394
y METHOD FOR MAKING A cELLULosIc PRODUCT Filed April 13,1956 s sheets-sheet s y vz,9z`s,sir4 METHODv non MAKING A C'nLLULosIC PRoDUCr l flohn Bletzinger and Howard N. Nelson, Neenah, Wis., .assignors to Kimberly/@Clark Corporation, a corporation of Delaware Application April 13, 1956, Serial No. 578,107
s Claims. (ci. r9- 1445) This invention relates to a cellulosic product, and more specifically toa catamenial or other tampon which comprises an absorbent, compressed bodyof cellulosic or other fibrous material or blends of two or more kinds of fibrous material.
The main objects of the invention are to provide a tampon or predetermined size which, when made `for catamenial and other fluid absorbing purposes, will be comfortable and .efficient in use; to provide a tampon which can easily be inserted into the vaginal canal and which, upon lbeing wetted in the canal, will rapidly expand4 both crosswise and lengthwise so as to cause the outs-ide surface of the tampon to quickly come into intimate engagement with the walls of the canal to prevent menstrual fiuid from flowing valong the walls and leak- .ing past the tampon without being absorbed thereby;
and'to provide 'a tampon of the character indicated in which the components are securely bound together so as -to prevent their separation .incident to. forces encountered when the tampon has servedits purpose and in wet condition'is withdrawn from .the vaginal-canal.
Other objects of the invention are to provide a tampon -ofthe character indicated which is adapted to be made of a substantial proportion of lowcost, relatively short fibers andin which tampon such short fibers will be effectively retained; to provide a tampon4 of the character indicated which may easily be made at a high rate of production by automatic machinery; and to provide an improved method of making the tampon whereby expanatent f sion of the compressed 4'article when wetted will occur substantially according to a predetermined pattern.
Other objectsfand advantages of the invention Will be Y understood by reference lto the following. specification and accompanying drawings (3 sheets) in which there 'is described and illustrated a. tampon embodying a sc'- leeted form of the inventionrand a method of making the same.
In the drawings: Figures 1 to 4 inclusive` are perspective illustrations of successive steps. in the production of an uncompressed bodyv which is4 subsequently compressed to produce a tam- 'representations of successive. steps by which tampon bodies such as shown in Figures 4 andv 5 are converted into the desired. compressed tampons. such as shown in Fig. 12-. Figures 1l. and 12. each include end and side 'elevations and Fig. 12. is on an enlarged scale;
Figures. 1-3 and 14 are schematic perspective representations of apparatusV for carrying out theV steps represented in Figures 6to 121 inclusive; and
Figure I5 is a schematic representation of another means for making a tampon according t'o the invention.
According to one example of theinvention, an absorbent, compressible tampon body is constructed mainly of ?tented Mar. i, iii-50 two elongated absorbent 'batts 1a and 1b of selected fibrous material, and a wrapper 2. The said batts 1d and 1b are here shown as of rectangular form in both longitudinal and transverse cross section as represented in Figure 1. The batts may be of other forms, especially in transverse cross section, for example, circular, semicircular, wedge or other regular or irregular shape. These batts or pads of fiber may be made of any suitable flbrous material or mixtures of difierent kinds of fibrous.material. For one example, they are desirably made of a mixture of cotton linters and crimped viscose rayon staple fibers in the proportions of about 60% cotton linters and 40% viscose rayon staple fibers (by weight), the rayon fibers having a denier within the range of about 3 to 15. A more detailed disclosure of the uncompressed tampon body shown in Figures 1-4 may be found in the copending Vapplication of William H. Burger, Jr. et al., Serial No. 577,139, filed April 9, 1956, which is also assigned to the assignee of the present invention.
Cotton designated by the term cotton linters, comprises cotton fibers of short length, usually within the range of 1/32 of an inch or even less up to about 3/16 of an inch. The viscose rayon fibers are preferably crimped or crinkled and generally of longer lengths, for example from about 1A: of an inch to about 3A of an inch or more and they are more resilient than the cotton liber component referred to. The resiliency of the rayon fiber .component provides a desirable force which causes reexpansion of the body from compressed condition to .which the. body will be converted as hereinafter ex'- plained. Y However, other compressed fiber bodies may also exhibit suitable expansive properties for the purpose of the present invention.
Another suitable fiber blend comprises about 50% of chemical wood pulp fibers (often known as flul), 10% of nylon fibers, and 40% of B-comber cotton fibers.
@ther fibers which will form an absorbent body may be used, and natural and synthetic fibers may be used either alone or in blends of two or more kinds. The fibers may be selected according to their lengths or weights, and various blends of fiber lengths or fiber weights or of both, and various kinds or types and grades of cotton and other fibers may be used. Wood pulp fiber is preferably used in the cotton-fiber-like form 'known as 11nd, but it. may be used in the form of crepe Wadding if desired.
The said blend of cotton linters and viscose rayon is .a very satisfactory one in that the rayon fibers are resilientand serve to impart to the pads a resiliency which is highly desirable in the finished tampon represented in Figure 12. The cotton linters in lbatt form provide excellent absorbing capacity.
in one example the pads la and` 1b made of said blend or" 60% cotton linters and 40% crimped rayon fibers, are 4 inches long, of an inch thick and 1% inches wide. These proportions are not essential and they are stated merely by way of an example of a size v from which a very acceptable tampon may be made.
Y As shown in Figure 1, the fiber pads 1a and 1b are disposed. in lspaced side by side coplanar relation on the wrapper 2 which is ofv highly pervious material such as open. mesh gauze or other suitable pervious material. The space between the pads is not critical, but is preferably within the range of about 1A@ to 1A of an inch when the pads are about 1%; of an inch thick. This spacing may be eliminated, especially with very thin or resilient pads, or made greater when thicker pads are used.
The wrapper sheet 2 is longer than the length of Itiber pads as illustrated, and also wider than the combined widths of said pads so that the pads may be placed. on the wrapper to provide marginal portions of the wrapper which project beyond the opposite ends of the pads and beyond the longitudinal side of one of said pads as shown in Fig. 1. End portions 3 and 4 of the wrapper are folded upwardly over the ends of the pads and inwardly over the respectively adjacent marginal end portions of the pads as shown in Figure 2. The folded marginal end portions 3 and 4 of the wrapper sheet may be adjusted as indicated at to cause the length of the wrapper between its folded ends to be substantially uniform from side to side for purposes which will presently appear. If desired, adhesive may be employed as indicated at 7 to maintain said end marginsl folded, but this is usually not necessary. When the pads 1a and 1b are of the dimensions above mentioned, the wrapper sheet 2 may be about 6 inches long and about 41/2 inches wide, these dimensions being only exemplary and not critical.
After the components have been brought to the .condition represented in Figure 2, the pad body 1b together with the Wrapper portions which embrace said body, are folded upwardly and inwardly over the pad body 1a so as to place the liber bodies 1a and 1b in face-to-face relation with marginal end portions of the wrapper disposed between the end portions of said fiber bodies as will be understood by reference to Figures 2 and 3.
The next step is to fold the projecting Wrapper side portion 5 of the wrapper with its folded ends, upwardly over the adjacent side of the assemblage and over the top thereof into the condition represented in Fig. 4. If desired, adhesive may be employed as indicated at 7 to secure the marginal side portions of the wrapper or jacket in position on the pad structure. When adhesive is used, it is preferable that it be rather sparingly used and it should be chosen to avoid the production of any hard or stiff areas or spots, and it should be non-toxic and otherwise free from objectionable effects on the sensitive walls of the vaginal cavity.
It is preferred that the width of the wrapper 2 be so selected, and that the fiber pads 1a and 1b be so placed on the wrapper that the free edge of the final fold 6 will terminate within the width of the underlying face of the pad body 1b in at least slightly spaced relation to the nearest side or corner of the tampon body. This 'will usually prevent said free edge of the wrapper portion 6 from possibly forming a harsh edge on the sur- 'face of the compressed tampon which will ultimately be `made from the uncompressed body described.
After the components are in the condition represented in Fig. 4, a suitable draw string 8 is attached. The draw Vstring 8 may be a moisture resistant mercerized, soft cotton or other suitable thread which is folded upon itself land knotted together at its free ends as indicated at 9.
The folded end 10 of the draw string is passed through the tampon body so as to pass through the two pad elements 1a and 1b, and through the wrapper margin 3 'between the end portions of said pads as well as through ment of adhesive as above mentioned may be omittedy or such adhesive may be employed in an area or areas near only the opposite end of the tampon body. The
'draw string or withdrawal cord is preferably located in Yoffset relation to the longitudinal center of the body as shown in Fig. 4 for a purpose which will presently appear.
It will be seen that the wrapper 2 completely encloses the fiber material absorbent bodies and that the only exposed edge of the wrapper material is the edge 11 of the last folded side margin 6. portions 3 and 4 of the wrapper are effectively retained in Also, the folded end' aaneen@ 4 folded condition by being gripped between the fiber bodies 1a and 1b.
In some instances, the pads 1a and 1b may be placed on the wrapper sheet so that marginal portions of the wrapper sheet project beyond all sides of the pad pair. This will permit all of said wrapper margins to be folded over adjacent portions of the pad pair inthe manner above explained in reference to the wrapery margins 3 and 4. Then, when the pad 1b or the pad 1a is folded with the contiguous wrapper portions over the other pad, the resulting structure will have all of the wrapper sheet edges embraced between the pads 1a and 1b.
As above stated, the wrapper 2 may consist of woven gauze, other open mesh thread fabric, or other suitable pervious fabric. Non-woven thread fabrics made by cross laying (instead of weaving) the warp and filler threads may be employed, and some or all of the warp threads may be of leno weave form to insure-stability of the thread position in the fabric. Stability of thread position may also be attained in open mesh fabrics of the character indicated by adhesively bonding crossing threads to each other at their intersections. l
Non-woven fiber sheets in which the fibers are adhesive ly bonded together or which sheets are otherwise reinforced to provide the desired strength in the sheet while at the same time providing a highly pervious sheet may be employed for wrapper purposes. Knitted or braided mesh material and any other sufficiently strong and pervi ous material may also be employed.
Open mesh wrapper material should be of such mesh that it will effectively retain in the absorbent body, any short ber component thereof, for example, the
vshorter fibers of a cotton linter component or o f a Huff component such as above mentioned. For a body which contains such short fibers, a suitable wrapper is provided by woven gauze having a thread construction of about 24 x 24 or by other fabric having comparable openness. In some instances, the wrapper material may be a more open thread-formed web having a lower thread construction countsay about 16 x S-and a facingl F (Fig. l) of cotton or other fibers frictionally or adhesively attached to the thread web, preferably on its inside face. Such a fiber facing serves in cooperation with the more open mesh fabric t0 effectively contain short fibers in the absorbent body, and it imparts a desirable smooth feel vto the outside of the wrapper, probably because of the 'projection of some ofthe facing fibers through the meshes `of the wrapper to the outside thereof. Such a vfibel" facing may be employed on smaller mesh fabrics .if desired but it is, in general, less important on smaller imesh fabrics.
Said ber facing may be very light; for example, it may have a basis weight within the range of 11/2 to 6 grams per square yard.
The uncompressed body shown in Fig. 4 is preferred for conversion into a compressed tampon according to the present invention, but the converting steps which are about to be described may be applied to or practiced with 14 through the thickness of the batt and extending lengthwise thereof along or adjacent the longitudinal centerof the width of the batt, the line of stitching being extended beyond one end of the batt to form a withdrawal cord 14a. As illustrated in Fig. 5 and for a purpose to be presently explained, the stitching which forms. the .Withdrawal cord, may be offset to one side of the longitudinal -center of the pad width-especially adjacent the end of the pad from which said cord 14a extends. The withdrawal cord 14a may be provided byv attaching aseparate string to the fiber body in any suitablemanner.
When such starting body comprises lthe aforesaid blend of 60% cotton linters and 40% crimped rayon fibers, 1t weighs aboutl 3 grams (including the wrapper) and corn;-
pression and re-expansion steps to which the body is subjected will result in temporary or intermediate 'and final dimensions approximately as hereinafter specified.
However, it should be understood `that the .specic di- Imensions may vary somewhat and that when other kinds oli starting bodies` are employed, the dimensions thereof may be different both at the start and in the intermediate stages even though the nished products are intended to be of the same size and shape.l One step in making aA compressed tampon from anuncompressed body such as specified in the preceding paragraph, is to compress the thickness T of the body to a predetermined thickness which is, `preferably somewhat less than the corresponding dimension of the compressed tampon which is to be made. vFor example, if the compressed tampon is to Vbe of cylindrical form about V2 inch-in diameter,` the thickness T of the uncompressed body may be compressed from its initial starting thicknessof about 3A of an .inch to about 3A of an inch.
lThis step is represented in. Fig. 6 where the reduced thick- Vness is representedby T1.
Another step is to compress the wide face Width W .of .the body to a reduced width W1 as represented in Fig. 7. The reduced width W1 is somewhat .greater than the corresponding transverse dimension of the compressed tampon which is to be made. For example, if the tampon is to be made approximately cylindricalin its finished form with a diameter of about 1/2 inch, the` face width W of the uncompressed body mayvrst be reduced to about SA; to 2% of an inch which is represented at W1 in Fig 7. l
A further step consists in reducingY the longitudinal kdimension L of the body to somewhat less thanv 1/2 of its initial length or, with reference to the compressed tampon being made, to about therdesired length of the compressed tampon or slightly less, for example,J .to about 11A; inches, vthis reduced length being indicated at Ll in Fig. 8. y
The foregoing thickness, Width and length compression steps constitute a series of compression steps which may be designated, for convenience, pre-.compression steps since they are preliminary to additional compression steps which result in the production of the compressed tampon of the required size.
After the body is pre-compressed to the condition represented in Pig. 8, the body is permitted to expand due toits inherent resiliency, this expansion, serving to en- ,large thev pre-compressed body to a condition mwhich the length andwidth are somewhat greater than corresponding dimensions ofy the compressedbody which is to bemade, as represented by the dimensions L2 and W2 respectively,while the thickness is also caused to expand to a dimension T2 which, like the dimension T1, is somewhat less than the diameter of the cylindrical body which is to be formed. The expanded length, Width and thickness dimensions are, respectively designated, 'L2, W2 and T2 in-Fig.v 9. For the example being described these expanded dimensions are approximately asfollows:
agentes `It, the tampon is to be, produced with, an applicator stick 'receiving socket 15 in one end (cee Milcent Patent 2,607,346, August 19, v1952) as represented in Figs. 11 land l2, such a socket is initially formed in the pre-com lpressed tampon body when the vlength of the starting body is reduced from the vlength L to the length L1 as `shown in Fig. 8. 4This socket "may be produced by pro- 'viding one of a pair of mutually opposed longitudinal vcompressing members with a projecting pin which will 'enter the string end ofthe tampon bodyv as an incident to the longitudinal compressing operation, Vthereby "to 'form a preliminary socket 15a in said string end of the body as represented in Fig. 8. This preliminary socket 15a may be formed to a depth which is 'somewhat more than the desired full vdepth of Vthe socket in the final vc ompressed tampon; vfor example, the` socket 15a may be made to a depth of about inch when the depth of the socket 15 in the finished product is to be about 5%; of an inch.y The diameter of the preliminary socket formation `15u may be slightly greater or approximately the same 'as the diameter ofthe socket 15 in the linished product.
In some instances, the socket 15 will be made cylindrical without coming to a point or it may be made only slightly tapered for a portion of its length or from end to end whatever the desired shape of the socket, the forming pin will be appropriately shaped.
After the pre-compressed 'tampon has expanded to a limited extent as represented in Fig. 9, it is subjected to a second longitudinal compressing step which is represented' in Fig. 10 Where `the llengthwof the. body is represented as having been compressedto the desired linal 'compressed length L3 which, in the examplefreferredjto is intermediate the pre-compressed length L1 and the Iexpanded length L2.` For example, vthe compressed length L3 maybe aboutv 1% incheswhen the pre-compressed length L1 is 1%' inches and the expanded length L2 is 2 inches. i
During the second longitudinal recompressi'on step, the thickness T2 of the' body may be maintained by providing the compression chamber with a corresponding dimension. 4 It is preferred that the dimension T2 of the re-expanded body be slightly less than the corresponding dimension of the compression chamber so as to. facilitate introduction of the expanded, `pre-compressed body into such chamber. For example, said compressing chamber dimension may be about 1/2 inch and the second step of longitudinal compression will cause the thickness of the body to expand to that dimension which is represented at T3 in Fig. 10. This slightly expanded thickness is approximately the same as the corresponding dimension of the completed compressed tampon.'
The longitudinally recompressed body is then subjected to another step of side compression whereby its Width W2 is reduced to a width W3 (Figi 11) which will expansion in' the direction of* length I' and thickness will usually bevery'slight. The re-expanded product Will be of approximately cylindrical shapev but withsl'ightly attened top and bottom surfaces illustrated in Fig. l1. The W3 dimension of the compressed tampon will expand to substantially 1/2 inch as indicated at' W4 in Fig. 12, the dimensions L3 and T3 usuallychanging so little that for practical purposesfthey may be regarded as un.
During the second longitudinal compression step represented in Fig. 10, the socket 15a may be reduced sub- .only to the indicated limited extent. 'locking effect by which such stabilization is obtained is vreadily released when the tampon is wetted in normal use, and the tampon then expands toward restoration of rthickness T1. .in connection with such transverse expansion. sion tends to occur in substantially the reverse order of :compression although it is not meant to say that expansion occurs in separate and distinct steps transversely and longitudinally.
. 7 stantially tothedes'ired vfinal size of the socket 15 by providing the appropriate longitudinal compression plunger with a socket forming pin of the required size. .The subsequent width compression step (Fig. 11) is effected with the socket forming pin in place and will :not materially affect the size of the socket 15. The side compression devices employed in the second side compression' step (Fig. 11) are provided with suitable concave faces to impart to the compressed body the more or less cylindrical form represented in Fig. 11.
In order to obtain a compressed tampon which is substantially stable in the condition represented in Fig. 12,
.the compression steps represented in Figs. 6 to 11 inclusive are effected while the tampon body contains a ,moisture content which will facilitate locking of the fibers lin their compressed or compacted condition subject only to the limited expansion already indicated. Thismoisyture content depends somewhat upon the particular character and kind of fibers employed in the fiber body. For the said blend of cotton linters and viscose rayon, la moisture content within the range of 8% to 14% of the weight of the body and uniformly distributed therein, appears satisfactory, a moisture content in the vicinity of 10.5% or 11% being preferred. To provide a moisture content such as indicated, the uncompressed tampon body may be subjected to steaming, spraying or any other suitable treatment which will result in the said moisture content condition.
When the fiber body containing a moisture content substantially stable and the compressed body expands Nevertheless, the
the dimensions of the uncompressed body but not fully to that extent. Initial expansion of the body upon wet- W1 or W2 of Figs. 8 and 9 respectively, and it tends to restore the thickness T3 to a thickness intermediate said initial thickness T and the preliminary compression Longitudinal expansion will also occur Expan- By causing substantial expansion to occur both transversely and longitudinally more or less simultaneously,
improved effects are obtained in respect of the establishing of adequate contact between the surfaces of the tampon and the walls of the vaginal cavity to prevent nary and final compression of the absorbing body with an intermediate re-expansion step is representative of one practical way in which the desired compression may be effected with relatively simple compressing equipment ,comprising separate preliminary and final compressing mechanisms, the tampon material being transferred from the preliminary compressing mechanism to the final compressing mechanism. However, it is not essential that the compressing operations be effected in such separated l steps with an intervening period during which re-expansion is permitted to occur. The described vcompressing steps may besubstantially continuously performed in a isingle compressing mechanism and without permitting said intermediate re-expansion. Such a continuous compressing method utilizes the above described preliminary thickness,'width, vand length compression steps to arrive v at a pre-compressed body as represented in Figure l0,
body B to form the socket 15a.
. Y 8 which, when of the'aforesaid blend of 60% cotton and 40% -rayon fibers, has dimensions about as follows:
in Figs. 13 and 14, and for effecting said compression in a continuous, single operation, in Fig. 15. The apparatus may embody many different forms and those shown should be understood as being merely exemplary.
The two stage mechanism comprises two units of `mechanism respectively represented in Figs. 13 and 14,
the mechanism shown in Fig. 13 being employed for .effecting the pre-compression or preliminary compression steps represented in Figs. 6 to 8 inclusive, and the mechanism represented in Fig. 14 is employed to effect the 4final compression steps represented in Figs. 10 and 1l.
As represented in Fig. 13, an uncompressed body B .is delivered into a chamber formed between a pair of reciprocably movable side compression plungers 16 and 17, the bottom of the chamber being formed by the bottom of a recess in a base plate 19 in which said side compression plungers 16 and 17 are movable. The top of the chamber is formed by a plate 20 which is hinged Yas indicated at 21 to the base plate 19. The cover 20 is adapted to be swung to an open position to permit placement of the tampon body B as illustrated in Fig.
13 and then closed into face-to-face relationship to the top face 22 of the base plate 19 and the corresponding top faces of said side compression plungers 16 and 17. When the cover 20 is thus closed, the tampon body B will have its thickness compressed to correspond with the depth of the chamber formed between said plungers 16 and 17, this depth being, in this instance, 3%; of an inch. By closing the cover 20, the tampon body B will be reduced in thickness as represented in Fig. 6.
The side compression devices 16 and 17 will next be advanced toward each other to reduce the width W to the pre-compressed reduced width W1 as represented in Fig. 7. While the dies remain in their advanced positions with the cover 20 closed, a plunger 23, which is longitudinally reciprocable in a guideway 24 provided in the base plate, is actuated to effect endwise compression of the body B against the end wall 25 of the compression chamber, the body B being thereby put in the condition represented in Fig. 8. This longitudinal plunger 23 is slidable between the advanced side compression plungers 16 and 17 and said longitudinal plunger may be provided with a pin 26 which will enter the end of the tampon The withdrawal cord 8 during these pre-compressing operations may be permitted to remain on the top surface of the body B or it may be compressed against the adjacent end of said body. Another way of handling the withdrawal cord it to provide the plunger 23 with a hole 27 into which the cord may be pneumatically drawn as the plunger advances.
The compressed body is then removed from the compressing mechanism and will expand approximately to the action of a suitable. reciprocating plunger 32 which is slidable .in said guideway or channel 23. A normally fixed top plate 33 extends over `the channel portion 28 immediately adjacent the abutment block 30. A pair of side compression plungers 3d and 3S are slidably .mounted .in said base plate 2.9 for reciprocating moyernent transversely of the length of said guideway 28, and
.said plungers have inner or adjacent ends 35 ofrnore or flCSS concave form so that when they compress the tampon body Bl between them, the body will be `given a more orjless cylindrical shape.
"-he longitudinal compression plunger 32 is at first operated to advance the tampon body B1 into the chamber formed between the side compressing plungers 34 and 35 and between the cover plate 33 and the bottom of the guicleway `28. Advancement of the plunger 32 is effected until its leading end ,37 becomes aligned with the side edges 38 and 39 of the Aguideway in which .the
side compression plungers .34 and 35 operate. This restilts-in the desired 'limited 4secondary Vlongitudinal com- Apression of the tampon ,body B1 which is represented in Fig. l0. While the plunger 32 remains in its advanced ...sented in Fig. l1.
position to "hold the tampon compressed longitudinally IQ the extent indicated, the side. compression plungers '34 and '35 are actuated to effect-side compression .S'o as 'to Areduce the width dimension W2 of the compressed ber ,poi-.tion which istraversed by the opposed trat'isiiers 'plunger elements `11b and 42h. The plungers 411D. and 4 2b may now be .advanced to eiiect transverse compres'- sion of the longitudinally compressed body to vtheviilth W3*as.'represented in Fig. l1. The body will re-en pand slightly as represented in Fig. l2 upon removal "from 'the compressing chamber.
JThe purpose of 'providing pairs of dies in the manner indicated 'is to permit the plunger portions 411; and 4 2b 'to effect the final 'transverse compression while the plunger mem ers 41a and 42a remain in the advanced `positions represented at 47 and 48 with the plunger elements `d4, V55a and 45b therebetween to confine the Vtampon body to the length of the chamber `in which said plungers dlb and 12b move transversely.
The finished tamponrepresented in Fig. l2, when made from a two part body enclosed in a wrapper as shown in Figs. l to 4 inclusive will have the wrapper material or jacket pressed into the body so that the jacket ma body to the desired final Width dimension W3 `as repre- During the longitudinal compression of the tampon by the plunger 32 the withdrawal cord 8 may be received in a `bore in the plunger 32', the cord lbeing pneumatically drawn into said bore.
In the apparatus represented in Fig. l5 for effecting .the desired compression in a continuous series of operations, a die chamber is formed 'between Opposed pairs of side compressing plungers, one pair Comprising plungers 41a and 411?, the opposed pair comprising plungersAZa 4and 42b. These pairs of plungers are reciprocated toward and from each other intermediate top Vand bottom plates (not shown) which cooperate with the plungers to form a chamber which is open at one en d and closed `at the other end by a member 43. A reciprocating longitudinal compressing plunger, comprising Va'center rod 44' and outsideV members 45a and 45h, is operative to ,feed an uncompressed tampon body B into the chamber or to hold it in the chamber if it is pneumatically or otherwise fed thereinto. 'I he plunger rod 44 may be equipped with a pin projection 46 which will easily enter the body B toform a socket 15 if such socket is desired.
The pad body B having been rst compressed or g formed to a thickness T1, is put in the chamber between the opposed pairs of side compression plungers and said top and bottom plates and said pairs of side compression plungers are advanced toward each other to effect Vthe initial transverse compression Vstep represented in 1iriig. 7.
The plungers of each pair have aligned end faces Vand they initially move as a unit so that theirl .end faces reach a preliminary advanced position indicated at i7 "and 43 respectively. In this preliminary advainced posi- "ition, `the width of the 'body Bis compressed to the. width W1 as represented in said Fig. 7.
While the pairs of plungers remain advanced to the positions represented at 47 and 43', 'the endwise. ,com-
pressing plunger members 44, V45a and 45 b 'are advanced as a `unit between said side compression plungers to efffeet longitudinal compression oftheber body B to a Ilength L1 which corresponds to the Width of the cham- .essere terial is not clearly identiable on the surface of the `tampon but is more or less hidden by some of the fiber y material which is forcedbutwardly through the interstices of the wrapper material. The surface of the tampon body is accordingly characterized by a surface which is softer and smoother than the wrapping material'itself. The jacket is more or less gathered around 'the surface of the tampon in proportion to the extent to 42 in Fig. 12.). the 'locks which hold it compressed, the jacket will also be released and will be capable o`f being expanded 'by the force of the expanding `liber body.. The inturned `end margins o f the wrapper fabric will remain gripped between the end portions of the fiber-body so that the 'Wrapper always completely surrounds and wholly'cion- -tains the fiber body.
We believe that effectiveness of the described method o f tampon making, that is to say, the improved characteristics of the tampon so made, are to a considerable extend, dependent upon the density of the pre-compressed body represented in Fig. 7. This density rin turn depends somewhat Vupon the kind of material of which 'the body is made. For example, a density of approximately v11 pounds per cubic foot gives satisfactory vrestiltsY for a fiber body which weighs about 3 grams '(i,n.
' -such roughness persists even lin the r'e-expandedtampon under normaluse conditions. The deep creases or folds are objectionable in that they. tend to resist re-eXPansiQn 4 of the body and reduce its absorbing capacity.
If the tampon body is made wholly of cotton fiber, .a vdensity of about 12 pounds per cubic foot in aprecornpressed body represented in Fig. 10 and of the size reerred'tQ, gives very good results.
It is not practicable to set forth specific densities or ranges .0f density suitable for each of the many `kinds of fiber bodies which may be made into tamponsaccording to this invention. For .the above described 3 gram body consisting of 60% of cotton linters and 40% crimped rayoniibers, ka satisfactory density .,rangeisabout 6;' 5 pounds per V(Il-lbic foot to labout 13 PUHdS p el-'fllbi foot in the precompressed body ofFig. 7, and this-density range may be considered generally applicable 'to other ure 6 does not generally produce creases or folds. 'pression of the width of the body to about one-half its` 'original width as represented in-Figure 7 may result in -the appearance of a few slight longitudinally extending density.
When the' density of the pre-compressed body is properly selected, compression thereof results in only relatively shallow folds or creases in the body and compaction of the body is effected mainly by forcing the fibers into more intimate engagement and interlaced rela- 'tionsh'ip whereby stability of the compressed body in normally dry condition is obtained. Complete elimination of such folds or creases is desirable and the described sequence of compression steps tends to effect such elimination in that the folds are made very small. One objection to large, deep convolutions is that they tend to produce extra hard, high density portions in the bends 'of the convolutions while permitting tbe leg portions which extend from said bends to remain softer. The
yhard density areas that hamper expansion of the tampon when wetted reduce its absorbing capacity.
By contrast, in the specic example described, the
'depth of the creases is generally not greater than about 1A; of the average diameter of the compressed tampon and only a small proportion of the creases attain that depth.
The depth of such creases in the surface of the tampon 'is not uniform but varies widely, and a majority of said creases range in depth from about 17428 inch to about l@ inch, when the body is of said 60% cotton linters and 40% crimped rayon fibers composition and the described 'sequence of compression steps is followed.
The initial thickness compression represented in Fig- Comcreases. The longitudinal compression step represented (in Figure 8 generally causes a number of shallow transverse folds'or creases to appear on both the wide and 'narrow faces of the body. When the pre-compressed `body of Figure 8 is permitted to re-expand to slightly more than tampon length as represented in Figure 9, the depth of the transverse creases will be reduced and the slight longitudinal re-compression represented in Fig. 10,
does not materially change the size of said transverse creases. Direct longitudinal compression` of the fiber body from the condition represented in Figure 7 to tarnpon length as represented in Figure 10, also results in ftheiformation of similar shallow creases. The final trans- "verse compression which reduces the width W2 to tampon width W3 effects some further longitudinal folding f but this appears to be minimized by resistance offered by the existing transverse folds andl of course the higher The longitudinal and transverse folds or creases each tend'to break up the continuity of the other so vthat not only the shallow depth of the folds but also the discontinuity thereof aid in the attainment of a smooth surfaced product.
The small transverse and longitudinal folds occur in vgreater numbers and frequency than when fewer but larger folds are formed. The greater frequency of the xsmaller folds also contributes to the formation of a `smooth surface on the compressed tampon. When the tampon is wetted and expanded, a few of the folds, probably the largest of them, may appear as creases in the surface of the expanded body.
Smoothness of the surface of the compressed body is highly desirable not only from an appearance standpoint, but also because it makes insertion of th'e tampon into the vaginal cavity easier and less discomforting. Surface smoothness in the wetted and expanded tampon is believed to aid in maintaining effective continuous contact, both circumferentially and longitudinally, between Such annessa 12v V imparts to the tampon when wetted, a capacity for expanding to a size intermediate its initlal uncompressed -size and its smallest compressed temporary size as repjgreater than that of a compressed tampon made of a like amount of fiber by conventional methods.
Another desirable feature of the tampon when produced in the manner described, is its tapered or rounded front or inner end portion as shown in Figs. l1 and l2,
lwhich is produced without significantly hardening said end portion, i.e., without significantly increasing the 4density of said end portion as compared with the density of the body portion of the tampon intermediate its end portions. The formation of the illustrated rounded end shape is initiated by the final longitudinal compression step in which the fiber body is compressed longitudinally against the concave, approximately semi-cylindrical end wall 31 of the die block 30; this imparts to the fiber body, a preliminary, approximately semi-cylindrical end. However, said rounded, approximately hemi-spherical end results primarily from the final side or transverse compression step. To obtain said rounded end shape by the final transverse compression step, the side compressing dies 34 and 35 in Fig. 14 or the side compressing dies 41b and 42b in Fig. 15 have their cooperating semicylindrical concave faces 36 terminated in mutually opposed hemispherical end .portion 36a. The said hernispherical end portions 36a of said cooperating faces apply pressure to the ber body at angles which appear to cause shifting or flow of the liber material in the adjacent end portion of the body lengthwise of the body to such an extent that the density of the compressed tapered or rounded end of the tampon is not significantly different than the density of said intermediate portion of the body. High density in the inner or front end portion of the tampon is somewhat objectionable because a tampon with a hardened end is not comfortably inserted and because the hardness tends to retard expansion of the front end of the tampon upon being wetted and this results in discomfort to the user.
There may be some increase in the density of the outer or rear end portion of the tampon body when it is cornpressed around asocket forming core such as the core or pin carried by the end 37 of the longitudinal compression plunger 32. This strengthens the socketed end portion of the body so that there is less danger of distorting said end portion as an incident to insertion of the tampon by means ofan inserter stick seated in such socket.
Various other fiber components may be employed instead of those specifically mentioned and the principle of pre-compression to attain a selected density, followed by additional final compression steps may be applied to other forms of compressible tampon bodies to produce a tampon having the advantages of the constructions described. Also, instead of pre-compressing a starting body to obtain a desired density as a part of an integrated method of procedure, the method may start with absorbent bodies of suitable size separated from a supplyof material which is of the desired density. Various other changes may be made while employing the principles of the described invention.
1. The method of making a compressed tampon from a substantially uncompressed elongated body of absorbent material of predetermined length and transverse size, said length and transverse size being greater than the length and transverse size of the desired compressed tampon, comprising the steps of compressing said body transverse- 1y` of its length to a predetermined reduced transverse size which remains greater than the transverse size of the desired compressed tampon, substantially maintaining said reduced transverse size and compressing the body 13 longitudinally to approximately the desired length of the finished tampon and again transversely compressing the body to a further reduced transverse size which is approximately the desired transverse size of the desired compressed tampon.
2. The method of making a compressed tampon from an elongated body of absorbent material having a predetermined dcnsity and of predetermined length and transverse size, said length and transverse size being greater than the length and transverse size of the desired compressed tampon, comprising the steps of compressing said body transversely of its length to a predetermined reduced transverse size which remains greater than the transverse size of the desired compressed tampon, substantially maintaining said reduced transverse size and compressing the body longitudinally to approximately the desired length of the finished tampon, and again transversely compressing the body to a further reduced transverse size which is approximately the desired transverse size of the desired compressed tampon, said predetermined density depending upon the kind of material in the body and being within a range which causes the compression of the body to develop relatively shallow folds or creases in the surface of the tampon.
3. The method of making a compressed tampon from an elongated body of absorbent material having a predetermined density and of predetermined length and transverse size, said length and transverse size being greater than the length and transverse size of the desired compressed tampon, comprising the steps of compressing said body transversely of its length to a predetermined reduced transverse size which remains greater than the transverse size of the desired compressed tampon, substantially maintaining said reduced transverse size and compressing the body longitudinally to approximately the desired length of the finished tampon, and again transversely compressing the body to a further reduced transverse size which is approximately the desired transverse size of the desired compressed tampon, said predetermined density depending upon the kind of material in the body and being within a range which causes the compression of the body to develop folds or creases in the surface of the tampon which have an average depth which does not exceed about one-eighth'of the average diameter of the compressed tampon.
4. The method of making a compressed tampon from a substantially uncompressed elongated body of absorbent material of predetermined length, width and thickness, all of said dimensions being greater than the desired corresponding dimensions of the tampon which is being made, comprising the steps of compressing the thickness of said body to a thickness which is not greater than the corresponding dimension of the linished tampon, compressing the width of the body to a width which is substantially greater than the corresponding dimension of the finished tampon, compressing the body longitudinally to a length which is not greater than the desired length of the tampon which is being made while substantially maintaining the body compressed transversely as aforesaid, permitting the body to expand longitudinally and transversely, re-compressing the body longitudinally to approximately the desired length of the finished tampon and incidentally causing the thickness of the body to expand to approximately the desired corresponding dimension of the tampon which is being made, and compressing the width of the body to slightly less than the desired width of the tampon being made, then permitting said width to expand to the desired tampon width.
5. The method of making a compreseed tampon from a substantially uncompressed elongated body of absorbent material of predetermined length, width and thickness all of said dimensions being greater than the desired corresponding dimensions of the tampon which is being made, comprising the steps of compressingthe thickness of said body to a thickness which is less than the corresponding dimension of the finished tampon, compressing the width of the body to a width which is substantially greater than the corresponding dimension of the finished tampon, compressing the body longitudinally to a length which is less than the desired length of the tampon which is being made while substantially maintaining the body compressed transversely as aforesaid, permitting the body to expand longitudinally and transversely, re-compressing the body longitudinally to approximately the desired length of the finished tampon and incidentally causing the thickness of the body to expand to approximately the desired corresponding dimension of the tampon which is being made, and compressing the width of the body to slightly less than the desired width of the tampon being made, then permitting said width to expand to the desired tampon width.
6. The method of making a compressed tampon from a substantially uncompressed elongated body of absorbent material of predetermined length and transverse size, said length and transverse size being greater than the length and transverse size of the compressed tampon, comprising the steps of compressing said body transversely of its length to a predetermined reduced transverse size which is greater than the transverse size of the compressed tampon, compressing the body longitudinally approximately the length of the compressed tampon, and again transversely compressing the body to a reduced transverse size which is approximately the transverse size of the compressed tampon.
References Cited in the le of this patent UNITED STATES PATENTS 2,076,389 Voss Apr. 6, `1937 2,340,311 Donovan Feb. 1, 1944 2,433,675 Parish Dec. 30, 1947 2,464,310 Harwood Mar. 15, 1949 2,710,007 Greiner et al. June 7, 1955 2,798,260 Niepmann et al. July 9, 1957