Note: Descriptions are shown in the official language in which they were submitted.
1 31393~ A~T-21
(~650/03~74)
TR~NSVERSE POCKET FORMING MACHINE
Technical Field
This invention relates to an improved method and ap-
paratus for molding composite nonwoven web products of various
shapes and sizes consisting of a more or less uniform intermix-
ture of randomly oriented fibers andJor particulate matter ob-
tained from separate supplies of individualized source material
such as textile fibers, paper-making fibers and powders.
BacXqround of the Invention
Nonwoven fiber webs or structures frequently consist of
a random yet homogeneous agglomeration of long and short
fibers. Long fibers are fibers of both na~ural and synthetic
origin that are suitable for textiles. They are longer than
0.25 inches and generally range between 0.5 and 2.5 inches in
length. Short fibers are suitable for paper-making and are
generally less than about 0.25 inches long, such as wood pulp
fibers or cotton linkers.
~5 Nonwoven web products may also comprise particulate
matter, such ~s absorbent powders, in combination with long and
- short ~ibers. For example, a highly absorbent powder or fiber
can be held within a pocket of fibers having good water moving
properties.
There are many di~ferent methods and devires useful for
making nonwoven webs or structures. Conventional carding or
garnetting methods produce nonwoven fiber webs, but these are
generally limited to textile length fibers. Methods o~ forming
nonwoven web products in pockets, i.e., having a non-uniform
cross section, a predetermined topography, or sharply defined
edges are also known.
~.,
2 ~ 3~3~3~
The ~Rando-Webber~ process may be used to make nonwo~en
webs. In this process, pre-opened textile fiber material is
delivered to a lickerin that opens the fihers further, and
introduces them to a high-velocity low-pressure air stream.
The fibers are randomly deposited on a condensing screen to
form an isotropic web. While a uniform web of textile fibers
can be obtained, this process i~ not suitable for use with
~hort fibers or blends of long and short fibers.
U.S. Patent No. 3,512,218 of Langdon descrihes two
lickerins and rotary feed condenser assemblies arranged in
parallel one after the other. Isotropic nonwoven webs are
formed with this apparatus by feeding fibers deposited on a
condenser mat to the lickerins, where the fibers are in-
dividualized. A single airstream is divided into two parts and
acts to doff the fibers from the lickerins and deposit them
onto a suction box, where the web is formed. This method
cannot be used to homogeneously blend two streams of fibers.
In U.S. Patent No. 3,535,187 of Woods there is describ-
ed apparatus for producing a layered web of randomly oriented
fibers joined at the interface of adjacent layers by a small
zone of textile length fibers extending across the interface.
Wood's device provides individualized fibers which are de-
posited on a pair of cylindrical condenser screens by a pair of
respective lickerins acting in cooperation with high speed
turbulent air streams that move faster than the lickerin in
order to doff the fibers. However, the air speed must also be
controlled so that the fibers do not forcibly impact on the
condensers. The condenser screens are positioned closely
adjacent to one another and the layers of fibers on the
condensers are compressed between the condens~rs to form a
composite nonwoven web with some blending at the interface
between layers. As a result, there is no substantial fiber
mixing ~one adjacent to the condensers, and the intermixing of
fibers is minimal.
One way of making a nonwoven web consisting of a mix-
ture of randomly oriented long and short fibers uses a milling
device to individualize ~hort fibers and a lickerin ~o indi~id-
ualize long fibers. The ~ibers are mixed in a mixiny zone, and
the mixture is depositad on a condenser to form a nonwoven web.
Though randomly oriented, the mixed fibers are stratified
rather than homogeneously blended. The long fibers predominate
on one side of the web and t~e short fibers predominate on the
other. In addition, undesirable clumps of fibers or ~salt~
occur in this web product, because the mill does not completely
individualize the short wood pulp fibers.
Another method used to make webs of mixed and randomly
oriented long and short fibers introduces pre-opened long and
short fibers to a single lickerin for individualization. How-
ever, the optimum lickerin speeds for long and short fibers are
different. To prevent the degradation of long fibers, this de-
vice must operate at the slower speed that is optimum for long
fibers. As a result, the speed and throughput of the device is
compromised.
Methods and devices which produce a blend of long and
short fibers without clumps or salt are disclosed in U.S0
Patent No. 3,772,739 of Lovgren. Lovgren pr~vides for the
separate and simultaneous individualization of each type of
fiber on separate lickerins, each operating at an optimum speed
for the fiber it opens. For example, long fibers such as rayon
are supplied to a lickerin operating in the neighborhood of
2400 rpm. Pulpboard is supplied to a lickerin operating in the
neighborhood of 6000 rpm, a speed that would damage long
fibers. The fibers are doffed from their respective lickerins
by separate air streams and are entrained in the separate air
streams. These streams are subsequently mixed in a mixing zone
in order to blend the fibers. ~he homogeneous blend is then
deposited in a random fashion on a condenser disposed in
proximity to the mixing zone. While the Lovgren apparatus is
useful, it does not lend itself to the preparation of a wide
variety of webs.
Another method of producing homogeneous blends of
fibers is disclosed in commonly owned U.S. Paten~ No. 3,740,797
of Farrington. Farrington discloses a method and machine
wherein supplies of fibers are fed to oppositely rotating
4 ~3~3~3~
parallel lickerins, which are operated at respective optimum
speeds -o produce individualized long and short fibers. The
individualized fibers are doffed from the lickerins by centri-
fugal force and by ~igh velocity air streams directed against
any fibers tending to cling to the lickerin structure. The
individuali~ed fibers from each supply are entrained in their
respective air streams and are impelled toward each other at
high velocities along trajectories that terminate in a mixing
zone, where at least a portion of the fibers from each supply
may be blended. A suction actuated condensing means co~muni-
cates with the mixing zone so that the blended fibers are
deposited on a condenser-screen to produce an isotropic web of
fibers. This screen is moved in a direction, i.e. the nmachine
direction,~ which is perpendicular to the axis of the lick-
erins. In addition, a baffle can be interposed between the airstreams to control the degree of mixing and the respective
location of the long and short fibers in the composite web.
It would also be advantageous to provide composite web
structures having a non-uniform cross sec~ion or predetermined
topography comprising zones of different fiber or particulate
materials and blends thereof. For example, a method and
apparatus for making nonwoven structures having selectively
absorbent pr~perties along the product's cross-section is
desirable, as in the case of hygiene products such as sanitary
~5 napkins. It is particularly desirable to provide for blended
composite structures having predetermined shapes with sharply
definsd edges.
Methods and machines for making nonwoven fluff pulp
pads and pre-shaped absorbent products are known, but do not
provide for selective blending and layering of pulp, textile,
and particulate materials. Conventional pocket-forming devices
can process only one material, usually pulp, and cannot be
readily modified to provide uniformly blended pads becauss of
the complex geometry inherent in the use of hammer mills or
disc mills and cylindrical product-forming surfaces. Typical
of these conventional devices are machines available from
Winkler & Dunnebier Maschenfabrik and Curt G. Joa, Inc. See,
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for example, U.S. Patent Nos. 4,560,379 and 4,598,441 of
Stemmler. [owned by WhDJ. PCT Application No. W0 85/04366 of
Johnson et al. is also of interest. Johnson teaches the use of
fiber-receiving molds disposed on a continuously rotating drum
selectively provided with a vacuum. Other foraminous drum ar-
ran~ements having circumferential cavities are taught by U.S.
Patent No. 4,592,708 of Feist et al. and U.S. Patent No.
3,518,726 of Banks.
An early method of making sanitary napkins is disclosed
in U.S. Patent No. 2,073,329 o~ Winter. Winter teaches that
patches of loose cotton fibers may be blown down onto a gauze-
like material at regular intervals in cooperation with a
suction means. Then pads of absorbent material may be placed
over the cotton patches, and the gauze folded and cut at
regular intervals to make the napkins. The loose cotton fibers
are directed to the surface of a moving wheel having spaced and
screened suction inlets adapted to receive and condense the
cotton fibers in uniform patches. The Winter process requires
several time-consuming and independent steps, followed by the
assembly of the composite structure from its component struc-
tures. It does not provide for a composite shaped and layered
structure formed by blending one or more fibrous and/or
particulate materials in an integral operation.
U.S. Patent No. 2,~49,646 of Clark is also representa-
tive of the prior art, and sets forth the problem of providingthree-dimensionally shaped structures having sharply defined
edgPs. Clark recites a prior art method wherein fibers are de-
posited continuously from an entraining air stream onto a
continuously moving foraminous belt provided with suction. The
belt is partially masked in order to provide deposition and
condensation of fibers into a web having the desired shape.
Clark notes that this method is disfavored because of the
leakage of fibers from the masked to the unmasked regions of
the belt, resulting in non-uniform layers. The prior use of
pans to catch fibers deposited by gravity is mentioned by
Clark, as is a method of cutting webs to desired shapes, or
separating webs using caul plates.
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The improvement o~ the Clark invention over the prior
art is a fiber depositing head whereby unblended web structures
having contoured edges are made by entraining previously
individualizPd fibers in a circular path within a circular
housing, delivering uniform volumes of entrained ~i~ers to a
moving collecting wall through openings in a foramino~s
separating wall of the housing, and fo~ming a continuous web
from the delivered fibers over collecting or ~asking members on
the collecting wall. A clean separation of the continuous web
into individual mats is achieved by a trough arrangement on the
collecting wall, which trough separates adjacent collecting
members and prevents leakage of fibers onto the collecting
members by trapping excess fibers. A means for separating the
masked collecting members from the end-product is also
described.
A number of absorbent articles, and methods and
machine~ for making them, are disclosed in the patents of
Xolbach, U.S. Patent Nos. 3,846,371; 3,860,002; 3,973,291; and
4,016,628. The '002 and '628 patents relate to adhesively
bonded composite structures having a medial portion of greater
basis weight than flanking end and side portions. These struc-
tures are obtained by providing discrete zones of relatively
high and low suction on a foraminous forming surface.
The '871 and '291 patents describe a moving pad forming
assembly ha~ing spaced, three-dimensional fiber-receiving com-
partments separated by air-impermeable regions. Each compart-
ment has the shape of the desired end-product and is providPd
with a foraminous lower surface and movable air-impermeable
side walls. Individualized fibers are provided to the compart-
ments, which in turn communicate with a fiber-entraining
suction means. Selective masking of the suction means can be
used to influence the density and weight of material collected
within regions of each compartment, and different air-suspended
fibers are deposited to different compartment sections at
different, non-overlapping, times to achieve different weight
and density zones within each compartment.
U.S. Patent Nos. 3,939,240 and 4,005,957 to Savich
disclose a method and an apparatus for forming fibrous pads.
Savich teaches a continuously driven condenser roll having
three-dimensional foraminous cavities about its periphery.
Each cavity is provided with a vacuum and is brought into
communication with a pad forming region that is~supplied with
air-suspended fibers. The fibers are deposited within the
cavity and form a layerl after which each layer i~ removed from
its cavity as a pad by another vacuum cooperating with a
proximate downstream transfer conveyor. The opening into each
cavity has a smaller surface area than the surface area within
the cavity, so that the resulting pads are consolidated within
the cavity, resulting in an increased basis weight, rather than
an advantageously shaped and sharply defined composite web
structure.
The prior art does not provide discrete composite non-
woven structures having predetermined shapes and consisting of
layers and/or vertical zones comprising blends of long fibers,
short fibers and/or particulate matter. A method and apparatus
capable of providing these structures is unknown, and in
particular the prior art methods do not teach a means of
producing such structures in a single continuous operation.
Summary of the Invention
The present invention is directed to the high-speed
production of blends of long and.short fibers, with or without
particulate matter, that result in a wide variety of composite
nonwoven web structures of different widths, thickness,
discrete shapes and compositions.
In an illustrative embodiment of the invention two
independent fiber sources driven by feed rolls are individual-
ized by parallel counter-rotating lickerins. The individual-
ized fibers are doffed from the lickerins by air streams and
centrifugal force, and are carried to a mixing zone. The
fibers may be randomly and uniformly mixed, or kept in
separate streams, and are deposited onto a condensing screen in
a condensing zone located below the parallel lickerins and
defined generally by the space between them. The scr~en
8 :~ 3 ~
supports and moves a series of product mold~ or pockets with
open tops and bottoms in a direction generally parallel to the
axes of the lickerins so that the lickerins deposit material in
the pockets. The fibers fill the pockets and are thus molded
into shapes defined by the shapes of the pockets.
Duct plates may be used to additionally define a path
between the lickerins and the top surface ~f the pockets, and a
suction slot under the screen may be preferably used to help
deposit the fibers into the pockets and onto the screen. Since
the screen travels parallel to the lickerin axes, there is a
high-speed transverse formation of a series of shaped struc-
tures. The transverse webber according to the invention pro-
vides a relatively long we~ formation zone that is limited
only by the practical length of the lickerins, the practical
angle of divergence of thP duct plates, and the practical
length of the duct plates from the mixing to the condensing
zone.
Composite and layered structures can be made by varying
the material introduced to the lickerins along the length of
each lickerin. Webs having different cross-sectional shapes
can be generated by varying the configuration o~ the duct
plates or the screen slot, by introducing baffles, or by
programmably driving the feed rolls.
Separate sources of short and long fibers, such as pulp
and rayon, respectively, are individualized by separate
lickerins and formed into a structure. Each fiber ~ource is
guided by feed roll~ and a nose bar into engagement with its
lickerin, and each lickerin is rotated at a high speed that is
suitable for the ~ibers it is acting on. The two lickerins are
parallel to each other and rotate toward each other, i.e. in
opposite directions. The nose bar and lickerin are arranged to
provide the optimum opening relationship for the fibers. Each
lickerin acts on its fiber supply and rapidly individualizes
the fibers through violent contact between the fiber supply and
the rapidly rotating teeth of the lickerin~
The streams of individual fibers are directed downward
and toward each other so they meet in a mixing zone. However,
g ~3~3~
the streams of fibers entering the mixing zone are dilute,
allowing the two 6treams to intersect each sther without a
subst~ntial number of collisions~ As a result the fibers from
the lickerin to the left of the condenser screen carrying the
molds tend to reach predominately the right ~ide of the ~creen
and visa versa. The deposition of fibers occurs as th~
condenser screen with the molds moves along the length of he
lickerins, e.g. 40 inches.
A different mixing pattern of the fibers can be accom-
plished by inserting a baffle into the mixing zone between the
lickerins. This baffle intersects par~ of each stream of
fibers and deflects it back in the opposite direction such that
the long and short fibers are spread across the lateral width
of the web. This results in a proportionally uniform mixing of
the long and short fibers across the web. If the baffle
completely intersects the streams, the material from the
lickerin on the left is reflected back to the left and vise
versa, so that a product with a distribution essentially
opposite that with no baffle is created.
The pockets determine the shape of the formed struc-
ture; but, the thickness and density of the web is determined
primarily by the fibers chosen, the proportion at which they
are mixed, the feed roller speed, and the rate at which the
condensing screen moves the pockets.
Different composition pulp and textile fibers can be
fed simultaneously to their respective lickerins in a side-by-
side relationship. In one such embodiment, pulp and t~xtile
fibers are fed into the device from the rear ~i.eG, toward the
entrance for the pocket molds into the frame) to form a bottom
layer of the structure, while another material is fed toward
the front (i.e., the exit for the pockets) to form a top layer.
These vertical zones can be varied by feeding different
materials along the lickerin length in cooperation with one or
more baffles.
In this way, different mixing zones can be defined, and
the resulting structure can be formed with horizontal and
vertical layers or zones. Each web zone is integrally as-
1~3~3~
1~
sociatPd with its adjacent web zone or ~ones by entangling of
fib2rs across the interface; and each zone has a diferent but
uniform composition of randomly oriented fibers.
The molds or pockets according to the pre~ent invention
conform to the desired product ~hape and are di~ected through
the condensing zone on a onveying screen. A suction means,
and a cover assembly adapt2d to prevent undesira~le leaXage of
air streams or loss of suction pressure are also provided in
the condensing zone.
Alternatively, the conveyor screen may be eliminated
and the molds may incorporate an integral condensing screen.
In such a case the molds may be fed serially to the condens~ng
zone disposed beneath the mixing ~one of the webber by means of
belts, chains, etc. In either case, within the condensing
zone, the molds mate with each other and with a sealing
assembly, provided for example by the ductsf so that all ~ the
fibers are condensed onto either the mold screens or the
conveyor screen, thereby forming individual shaped pads of
fibrous material.
The pocket-forming condensing means is interchangeable
with a continuous web condensing screen comprising a foraminous
conveyor belt, provided that in all cases t~e direction of
motion of the condensing screen is parallel to the lickerin
axes. Although a pocXet-forming condansing means can be used
with a conventiona~ double-lickerin webber~ such a method and
apparatus i~ limited ts two material~ and therefore cannot
produce horizontal layers and vertical zones within the ~olds.
Production capacity in a oonventional we~ber can only be
increased by increasing the lickerin length and forming pockets
in parallel, resulting in a very complex machine. By using a
transverse webber, capacity can be increa~ed by increasing the
lickerin length and the linear speed o~ tha pocket~ or molds.
~'
~313~3~
11
According to a broad aspect of the present
invention, -there is provided a pad product forming
apparatus which comprlses first feed means for
feeding a fibrous material to a first fiberizing
station at a first location. Second feed means is
provided for feeding a fibrous material to a second
fiberizing station at a second location. Means is
provided to define a mixing zone between the
fiberizing stations. First and second lickerins are
mounted for rotation toward each other about
respective parallel axes. A portion of the outer
periphery of the first and second lickerins is
adjacent to the first and second feeding means,
respectively, at the first and second fiberizing
stations, respectively. The first and second
lickerins are engageable with -the fibrous materials
fed to the respective fiberizing stations so as to
open the materials and produce individualized fibers
moving in first and second streams, respectively, in
trajectories toward each other and the mixing zone.
Conveying means, that is at least partially
permeable to air and moves parallel to the lickerin
axes, is located beyond the mixing zone. A
condensing zone is provided between the conveyor
means the mixing æone. The conveyor means enters
the condensing zone at an entrance end and leaves at
an exit end of the condensing zone. At least one
mold, separate from the conveyor means and having a
predertermined pocket-shape corresponding to the
desired individual shape of the pad, is provided.
The mold is adapted to receive therein fibers in the
air stream from the mixing zone and being introduced
to the condensing zone by the conveyor means. A
foraminous surface is provided in contact with the
6 lower surface of the mold and is at least in partial
~3~3~
lla
communication with an air permeable portion of the
conveyor. A vacuum means is provided in selective
communication with the condensing zone through the
air permeable portions of the conveyor and the
foraminous surface while the mold is passing through
the condensing zone. The vacuum means tends to draw
air-entrained fibers into the molds for condensation
therein on the foraminous surface.
According to a further broad aspect of the
present invention, there is provided a method of
forming a pad of fibers comprising the steps of
feeding a first source of fibrous material into
engagement with a first lickerin. A second source
of fibrous material is also fed into engagement with
a second lickerin arranged with its axis parallel to
the axis of the first lickerin. The first and
second lickerins are rotated toward each other about
their axes such that the fibrous material is opened
so as to form individual fibers. The fibers are
doffed from the first and second lickerins in the
form of two fiber streams directed toward each other
and into a mixing zone. The fiber streams are
conveyed from the mixing zone to a condensing zone.
The fibers are conveyed into an individually shaped
pad having a greater proportion of one of the fibers
in a first portion of the pad than in a second
portion of the pad within at least one mold, while
conveying the mold through the condensing zone in a
direction parallel to the axes of the lickerins.
The mold is provided with a foraminous surface,
separate from the mold, in contact with the mold's
surface remote from the fiber streams so as to allow
accumulation of fibers in the mold.
:~3~3~3~
llb
According to a still further broad aspect of
the present invention, there is provided a method of
forming a pad of fibers which method comprises
feeding a first source of fibxous material into
engagement with a first lickerin. A second source
of fibrous material is fed into engagement with a
second lickerin arranged wi-th its axis parallel to
the axis of the first lickerin. The first and
second lickerins are rotated toward each about their
axes such that the fibrous material is opened so as
to form individualized fibers. The fibers are
doffed from the first and second lickerins in the
form of two fiber streams directed toward each other
and into a mixing zone. The fiber streams are
conveyed from the mixing ~one to a condensing zone.
The fibers are condensed into an individually shaped
pad within at least one mold, while conveying the
mold through the condensin~ zone in a direction
parallel to the axes of the lickerins. The mold is
provided with a foraminous surface, separate from
the mold, in contact with the mold's surface remote
from the fiber streams so as to allow accumulation
of fibers in the mold. The iber streams are
baffled to vary the mixture of the fibers
accumulating in the mold as the mold moves in the
direction parallel to the lickerin axes.
Brief Description of the Drawinqs
The foregoing advantages and numerous other
features of the invention will be more readily
understood and appreciated
~3~3~
llc
in light o~ tha following detailed de~cription and accompanying
drawings, wher~in:
~ ig. 1 is a schematic view of a transverse webber
equipped with pocket molds according to the invention, ~howing
the main r-omponents th~reof;
Fig. 2. i~ a more detail2d cross-sectional view of an
apparatus according to the invention;
Fig. 3 is a side view of the ~pparatus of Fig. 2;
Figs. 4 and 5 illustrate perspective ~iews of single
and double pocket molds;
Figs. 6 and 7 are perspective views of nonwoven web
pads made according to the present invention;
Figs. 8~10 illustrate cross-sections of exemplary non-
woven fiber pads made with apparatus according to the present
invention.
DesCri~t i o~ Illustrative Embodiments
Figs. 1 and 2 show perspective schematic and cross-
sectional views of the main components o~ an apparatus accord-
ing to the invention. The invention i~ adapted to combinevarious *ibers, e.g. hort and long, into a nonwoven structure
in a pocket or mold so as to form a product structure having
variable hori~ontal and vertical cro~s-sectional compositions.
Principally the apparatus comprises two lickerins 10, 20
operating in parallel. One lickerin 10 i~ adapted to in-
dividuali~e short fibers and the other lickerin 20 individual-
izes long fibers. The individualization of t~e fibers, but not
formation of the structure, is generally perfo~med according to
commonly owned U.SO Patent No. 3,740,797 to FarringtonO
Ref~rring first to the short fibers, shown on the left,
wood pulp A (Fig. 1) in the form of a pulpboard 30, is directed
hetween a plate 11 ~Fig. 2) and a wire wound feed roll 12. The
plate ll has a nose bar 13 on its lower part, which provides an
anvil for the pulpboard 30 during individualization of the
~hort fibers. The ~ibers are indiv~dualized by the rotating
lickerln 10 di~posed below the feed roll 12 and operatively
. ............ - . . . - . . . .. .. . . .
12 ~3~
adjacent to the nose bar 13. The nose ~ar 13 assists in
directing the pulpboard 30 along a path de~ined by the plate
11, the feed roll 12, the lickerin 10, the nose bar 13 itself,
and an inclined face 15 adjacent to the lickerin 10. These
elements form a fiberizing station where the fibrous material,
i.2., pulpboard 30, is converted into individual ~ibers. Ths
inclined face 15 is ~paced a short distance from the teeth 16
o~ the lickerin 10 and the pulpboard 30 is individualized into
fibers by the teeth ~6 of lickerin 10 acting on pulpboard 30 as
it is brought into contact with the teeth 16 by the nose bar
13.
Typical short fibers include wood pulp fibers from
various types of wood, cotton linters, asbestos fibers, glass
fibers, and the like. Wood pulp fibers are the most frequently
used, due to their low cost and ready availability. Pulp
fibers are commercially available in the form of pulp boards of
varying sizes and thicknesses.
For short fibers, the nose bar 13 may have a relatively
flat sidewall 14 tFig. 2). The feed roll 12 is eccentrically
mounted to permit adjustment relative to side wall 14 and nose
bar 13, as shown for example in Fig. 2 by bracket 19. The
bracket 19 and feed roll 12 are resiliently biased to direct
the pulpboard 30 against the nose bar 13 by Xnown means, and
drive the pulpboard into engagement with the teeth 16 of
lickerin 10. This design permits the use of pulpboards of
varying thicknesses.
Feed roll 12 is supported on a sha~t and is rotated by
conventicnal motor means (not shown). The feed roll 12 is
rotated at a speed determined by the rate at which the pulp-
board 30 is to be fed to the lickerin 10. This rate determinesthe amount o~ pulp fibers deposited to form the structure in a
unit of time. The pulpboard 30 is fed to the feed roll 12 in
the direction shown by the arrow in Fig. 1.
The lickerin 10 is likewise supported on a shaft and is
rotated at a predetermined speed by a conventional motor ~not
shown), adapted to rapidly and reliably ~ray and comb the pulp-
board 30 by engagement with the teeth 16 until individual
13 ~ 3 ~
fibers are liberated from the pulpboard. Sh~rt fibers in~
dividualized by lickerin 10 are carried to a mixing zone 40.
Speeds in the neighborhood of 6000 rpm have been found suitable
for this purpose. The teeth 16 are chosen to have an optimum
profile for the chosen æhort fiber material represented by
pulpboard 30O
~ ong fibers are individualized in much the same manner
as the short fibers, as shown on the right side of Figs. 1 and
~. Typical long fibers include synthetic fibers, such as
cellulose acetate, vinyl chloride-vinyl acetate and viscose
staple rayon fibers, and natural fibers, such as cotton, wool
or silk. Long fibers, such as rayon, are commercially avail-
able in bales, with varying fiber lengths.
A source of long fibers is provided, usually in the
form of a carded batt 32, as when rayon is used as the fiber
source. Batt 32 is introduced to lickerin 20 via a second wire
wound feed roll 22 acting in cooperation with a plate 21 and a
nose bar 23. However, the nose bar 23 (Fig. 2), adapted for
use with long fiber sources, differs from the nose bar 13 used
20 with pulp. Since rayon and other long fiber sources lack the
physical integrity of pulpboard, the batt 32 must be more
positively restrained and directPd into engagement with the
lickerin 20. As shown in Fig. 2, the nose bar 23 is curved to
essentially conform to the adjacent surface of the second feed
roll 22. In this manner, the ~ibers in the rayon source are
maintained in position with respect to the second feed roll 22
until they are delivered to the teeth 26 of lickerin 20.
The lickerin 20 is rotated at speeds such t~at the
teeth 26 can comb long fibers from the batt 32 without degrad-
ing or damaging the long fibers. Speeds in the neighborhood of3000 rpm have been found suitable for this purpose. The teeth
26 of lickerin 20 are generally shorter than the teeth 16 of
lickerin 10, and have a smaller pitch.
A support structure or frame and drive means are, of
course, provided for the various elements of the invention, as
shown generally in the figures. Additionally, the lickerins,
nose bars, feed rolls, etc. can be adjusted with respect to
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14
each other in order to achieve optimal results.
The long and short fibers may be individualized simul-
taneously or sequantially, and as shown in Fig. 1 there may be
more that one type of each fiber (i.e., short fiber pulpboards
A, B and long fiber batts C, D) distributed over portions of
each lickerin. The licXerins 10, 20 are rotated toward each
other, as shown by the arrows in Figs. 1 and 2~ The fiber
sources, their distribution, and the speed and relative
proportions at which they are individuali7ed are chosen in
order to produc~ the desired structure and combination of
fibers.
The doffing of the individualized fibers from the
lickerins, and the transmission of the fibers through the
mixing zone 40 to a condensing zone 44 is assisted by air
streams. As shown in Fig. 2, high velocity air can be drawn by
suction created by a high vacuum chamber 49. This vacuum is
formed by a fan driven by a motor (not shown) and drawn through
duct 50 ~Fig. 1). As a result air is drawn past the licXerins
10, 20 and the nose bars 13, 23, through the mixing zone 40,
pocket molds 402 and the condensing screen 42. The fibers are
entrained in the respective air streams and impelled to move
rapidly and reliably from the lickerins 10, 20 toward each
other in the mixing zone, and to pass through the mixing zone
to the condensing zone, where they form the pads 45 in pockets
402.
According to the invention, the condensing zone 44 is
defined within a space below and proximate to the mixing zone
40, just above the condensing screen 42, and between duct
plates 39. The length of the condensing zone 44 corresponds to
the length of the lickerins 10l 20. Thus, the condensing zone
44, according to the invention, is in the form of a long narrow
trough adapted to receive individualized fibers from above.
The vacuum chamber 49 has the endless conveyor or con-
densing ~esh screen 42 wrapped about it. The suction force
from chamber 49 is applied to the condensing zone 44 through
the mesh screen 42, for which a suitable aperture 47 is
provided (Fig.2) in the top of chamber 49. Alternatively, the
15 ~3~ fi
pockets may have individual bottom screens 450,in which case
mesh screens 42 can be replaced with a simple means for
conveying t~e pockets through the condensing zone. The suction
force may then extend through the bottom screen 45Q of the
pockets 402 ~Figs 4 and 5), and out of the top o the pocket
to the condensing zone.
The aperture in the vacuum chamber generally corre-
sponds to the cross section of the space defined by the width
of the pocXet. The conveyor screen 42 is positioned to travel
below and in communication with the condensing zone 44, in a
direction that is parallel to the axes of rotation of the
parallel lickerins 10, 20.
The condenser screen 42 is guided over conveyor rollers
52, 54, such that, it may pass ~bout the high vacuum chamber
49. One or both of the rollers 52l 54 are driven so as to move
screen 42 at a controlled rate.
The screen 42 may communi~ate with other conveyors,
thereby delivering the pads 45 in the pocket molds for further
processing as desired. Such processing may include bonding, as
described for example in Lovgren, U.S. Patent No. 3,772,739,
shape-forming procedures, and final finishing of the web
product.
In order to seal off the condensing zone 44, and to
maximize the efficiency of the suction fan, duct plates 39 are
extended downward toward the screen 42 and terminate above the
top surface of the pocket. The duct plates 39 may additionally
be provided with floating seals 53 ~Fig. 2), which are biased
into contact with the top surfaces of the pockets by a spring
located behind the floating seals in a recess in duct wall 39.
Lickerin covers 55 may also extend about the outer periphery of
the lickerins and engage plates 39.
At the places where the pockets 402 enter and leave the
condensing zone 44, sliding seals 57, 56, respectively, are
provided on duct plates 59 (Fig. 3). The seals 56, 57 are
disposed b~tween the parallel edyes of duct plates 39 and are
free to float on the surface of the screen or pockets to accom-
modate movement of the screen and the pockets. When the
16 ~3~
pockets exit the condensing ~one 44, they pass beneath ~eal 56.
Besides maintaining the vacuum, the duct plates 39 ~erve to
guide the fibers to the condensing zone 44 and, together with
the duct plates 59, the floating seals 53, 56, 57, they improve
the efficiency uf the suction air flow.
When the molds 402 are within the condensing zone 44,
they are each in aealable contact with their serially adjacPnt
molds in the machine direction, and are in ~ealable contact
with the sealing assembly at the sides, so that the only
available path for air-entrained fibers leads them into the
molds 402. In this manner, a series of individual web struc-
tures is formed, each having a discrete contour defined by the
shape of the mold 402. Exemplary products made according to
this method and apparatus are shown in Figs. 8-10.
The molds 402 may be permanently affixed to the con-
veyor screen 42, which is in the form of a continuous belt or
chain, such that they continuously circulate through the
condensing zone 44, with the end product removed from the molds
402 at a collection point downstream of zone 44.
In the alternative, the molds 402 can be fed from a
cartridge-type assembly 430 (Figs. 1 and 2), so that a series
of unconnected molds 402 pass through the condensing zone 44
and are thereafter available for further processing prior to
removal of the wsb product. As shown, the cartridge assembly
430 is a vertical rectangular structure, whose top is open to
receive a stack of molds 402. The lower end of the side walls,
except for wall 432 adjacent the condensing zone 44, are in
sealing engagement with th~ condensing screen 42. At the base
of wall 432 there is an opening 434 that is slig~tly larger
than the cross section of one of the molds 4020
Since the conveyor screen 42 is moving, it makes fric-
tion contact with the lowest of the stack of molds in assembly
430 and drives it forward (to the left in Fig. 3) into the con-
densing zone beneath the lickerins 10, 20. Seal 57 is provided
at the entrance of the molds to the condensing zone to maintain
the vacuum. When this seal is used, the cartridge assembly 430
need not be immediakely adjacent the condenser. Instead it can
17 ~3~3~
be at any oonvenient location along the conveyor, up ~tream
from the condenser.
In order to improve the operation of feeding the pocket
molds 402 into the condenser zone, the screen and the bottom of
the molds may be coated with high friction material. Also
small hooks may be spaced along the conveyor ~creen to engage
the lowest mold and drag it into the condenser.
The device according to the invention may also be pro-
vided with a retractable one piece or multiple-section baffle
60 disposed within a plane passing perpendicularly between the
lickerins 10, 20 and intersecting the mixing zone 40. Although
the baffle can be placed so that a downward leading edge falls
at any predetermined point at or above the moving condenser
screen 42, three distinct qualitative positions can be defined.
When the baffle 60 or a part of the baffle is in the up or
fully retracted position, its leading edge is removed from any
~unctional contact with the fiber streams leaving the lick
erins. When the baffle 60 or a part thereof is fully down, its
downward leading edge is at or above the screen 42 at a
predetermined position within the mixing zone 40 where it
completely intercepts the fiber streams. Finally, the baffle
6Q or one of the segments can be positioned so that its
downward leading edge corresponds to a predetermined blend
point within the mixing zone 40 where it partially blocks the
fiber streams. A wide variety of composite structures,
heretofore unknown, can be generated by the invention by
varying the positions of or portions o~ the baffle 60 and by
feeding one or more materials via each of the feed rolls 12, 22
adjacent these baffl~ portions. Figs. 8-10 illustrate ex-
emplary composite structures according to the invention, and asdescribed according to the following examples. Figs. 4-6
illustrate the shape of molds that are used to make products.
The pockçt molds 402 delivered to the condensing zone
44 may be of the type shown in Fig. 4. This mold is generally
rectangular in outer shape and may be made of any convenient
material, i.e. wood, plastic, metal, etc. A recess 445, having
the shape of the desired final or intermediate product, is
18 1~3~36
formed completely through t~e mold. The bottom of the mold,
however, may be clos~d with a screen mesh 450. As a result the
vacuum force can be directed through the mold, but the fibers
entrained in the air streams caused by the vacuum force are
intPrcepted by the screen 450. The ~ibers cDllect in the
recess 445 as the mold moves through the condensing zone.
These fibers form a shaped structure of ~ntangled fibers. In
particular the n8~ shaped mold of Fig. 4 results in a pad of
fibers, which after further processing, is useful as a form-
fitted feminine sanitary napkin.
Other ca~ity shapes can be used to create other three-
dimensional pad shapes. The upper mold 460 of Fig. ~ has a
rectangular recess 449 and would create a rectangular pad. The
lower mold 465 in Eig. 5 has circular recesses 451 that produce
two circular disk pads. If desired, molds may be stacked one
above the other; so long as the upper mold cavity overlays and
is larger than the cavity in the lower mold. Further, in
stacking the molds, the screen 450 for the upper mold must be
removed so that the fibers in the upper mold are linked with
those in the lower mold. In Fig. 7 there is shown a product
made by stacking molds 460 and 465, forming a web in them and
turning the resulting pad upside down to sject it from the
molds.
It will be understood by skilled practitioners that
these examples represent only a few of the many new structures
according to the invention. Moreover, it will be evident from
the examples that, because of the transverse discharge of the
forming web and the placement of the pocket molds, a uniformly
blended web can not be obtained in the same manner as in known
devices, such as the Farrington method and apparatus, of the
previously identified Farrington patent. On the contrary, the
transverse pocket webber according to the invention tends to
deposit the fibers into a three dimensional web structure
according to unique zone-forming patterns. These patterns can
be manipulated to produce new and useful composite structures.
Example 1
Two different fiber materials 30, 32 in the form of
19 ~3~3~3~
short and long fibers, respectiv~ly, were delivered to the feed
rolls 12, 22 respectively, with each different fiber source
being coextensive with one of the lickerins 10, 24. When the
baffle S0 is in the up position, a composite web having three
lat~ral zon~s is formed in the pocket molds, each running in
the machine direction. The mold may be a staoked v~rsion of
molds 460, 465 to Porm a product shaped as in Fig. 7. A
schematic cross-sectional view o~ this product along line 8-8
of Fig. 7 is shown in Fig. B. The zone-likP composite struc-
ture is a consequence of the trajectories of the fibers doffedfrom the lickerins, passed through the mixing zone 40 and then
formed into a transverse web in the mold while the mold is
within the condensing zone 44.
When the baffle 60 is up, it does not alter the dilute
fiber air stream trajectories as they pass through the mixing
zone 40 to the condensing zone 44. The fiber air streams and
their entrained fibers retain a component of motion tending to
throw them away from their respective lickerin and toward the
web on the side of the opposing lickerin. As a result, the
fibers tend to pass each other within the mixing zone 40
because the streams are so dilute that there is little tendency
for fiber collisions. Thus, the fibers are predominantly
deposited toward opposite sides of the mold in the condensing
zone 44. As shown in Fig. 8, short fiber~ A originating from a
left-hand lickerin tend to form a narrow riqht-hand fiber zone
A containing predominantly fibers A. The long fibers B
originating from the right-hand lickerin tend to fo~m a narrow
left-hand zone B containing predominantly fibers B. Between
the fiber zones A and B is a wider transition zone containing a
blend of fibers A+B. At the boundaries of the zones the fibers
are entangled so that the web is formed in one piece.
Example 2
~ he fiber sources of Example 1 are used, but the baffle
60 is positioned at a blend point within the mixing zone 40 in
order to influence the trajectories of the individualized
fibers prior to fin~l deposition as a web in the moldO The in-
dividualized fibers passing through the mixing zone 40 and on
~3~3~6
to the condensing ~one 44 from each lickerin fall within a
range or angle of trajectories, in the manner of a spray
exiting a noz~le. The baffle 60, when positioned at the
predetermined blend point, intersects at least part of the
trajectory angle, causing some of the fibers enkrained in the
air flow within that part of the angle to bouncs off the baffle
60 back toward its own originating side of the condensing zone
44.
With the blend point chosen so that approximately equal
volumes of fiber from each lickerin are redirected by the
baffle 60 as are permitted to pass under the baffle 60 without
interruption, a uniformly blended web of short and long fibers
A+B is obtained. The blend point can, of course, be chosen to
provide a wide variety of fiber deposition patterns and
resulting nonwoven web structures.
Example 3
In yet another embodiment~ the baffle 60 is placed in a
down position, approximately 2 inches above the screen 42. The
two different fiber sources R, B of Example 2 are used such
that each fiber is supplied over an operative length of one of
the parallel lickerins 10, 20. In this case, substantially all
of the fiber trajectories are interrupted by the baffle,
tending to throw the fibers back toward their originating side
of the condensing zone 44. The result is a web similar to the
web in Example 1, but with the ~iber zones A and B in reverse
order, and a narrower transition zone A+B as shown in Fig. 9.
It should be appreciated that regardless of the posi-
tion of the baffle, there will be some distribution of both
long and short fibers across the web due to the turbulent air
flow. Thus the zone representations in Figs. 8 and 9 merely
show the predominate fibers in each. The proportion of fibers
in each zone may also be regulated by the rate at which the
fiber sources 30, 32 are fed to the lickerins. A fiber fed at
a Paster rate will produce a greater concentra~ion of ~hat
product in the web, although it will be distributed across the
web in a manner determined by the baffle position.
~313~3~
21
Example 4
Each lickerin 10, 20 naed not be ~upplied entirely wi~h
one fiber source, providad that all of the fibers ~upplied to
each lickerin conform to the fiber type (short or long) for
which the lickerin is adapted. Thus, for example, four fiber
sources A-D are equally distributed among the two lickerins,
each such source covering half of its respectiYe lickerin.
Moreover, the fibers may be fed into the lickerin by feed
rollers rotating at different speeds. Fig. 1 also illustrates
this embodiment. Two different pulpboards 30, 31 for producing
short fibers A, B are fed to lickerin 10 and two different
textile fibers batts 32, 33 for producing long fibers c, D are
fed to lickerin 20. The fiber combination A, C toward the
entrance end of the apparatus produce a lower layer of the web
while the fiber combination B, D toward the exit end of the
apparatus produce an upper layer.
The multiple fiber supplies A-D of Fig. 1 are fed to
the apparatus with the baffle in a blend point position to pro-
mote uniform mixing and deposition of fibers. The two rearward
fiber sources A and C in the machine direction supply their fi-
bers to the mold first. As this portion o~ the mold mo~es
toward the exit it passes below the transition between sources
AC and BD, and a transition layer having a uniform mixture of
all four fibers is laid down on top of the lower layer. As the
screen portion moves under the region of the lickerins which
are fed fibers B, D, these are deposit~d as an upper uniformly
blended layer of B and D in order to form the product whose
cross ~ection is shown in Fig. 10. If the baffle 60 is made in
a plurality of sections, these sections can be individually set
to vary the blend ratio in different layers of the product.
For example, the two layers shown in Fig. 10 can be in the form
shown in Fig. 8 and 9.
O er Variations
A product in which a middle layer is surrounded by
other layers can be vPry advantageous as a absorber, e.g. a
diaper or sanitary napkin. With such a product the inner fiber
blends are selected to be high absorbency fibers. For example
:~3~3~3~
22
this layer may be made predominately of pulp or super absorbing
fibers. The outer fibers are ~elected for their wicking pro-
perty, i.e. the ability to move liquid. For example, rayon
fibers have good wicking properties. With such a product the
moisture is directed away from the user's skin and clothing by
the wicking fibers and is retained in the center of the product
by the high absorbency fibers.
If the feeding of the pulp or high absorbency fibers is
intermittent, patches of this material will he buried in the
pad formed.
Various other products can be made in segments by
starting and stopping the condenser screen and by starting and
stopping or sequentially feeding the various fiber materials
A,B,C,~ D to the lickerins. Also, fibers may be included which
provide properties to the product other than moisture handling.
For example a fibrous material with great resiliency may be
used to give a product, e.g. a napkin, a springy characteristic
that makes it feel like a plush material.
While the present invention has been particularly shown
and described with reference to preferred embodiments thereof,
it will be understood by those skilled in the art that various
changes in form and details may be made therein without
departing from the spirit and sco~e of the invention.
