Seam integrity in multiple layer/multiple seam press fabrics

An on-machine-seamable papermaker's fabric includes a first and a second base fabric, each of which is joinable into endless form with a seam. The first and second base fabrics are attached to one another by at least one layer of staple fiber batt entangled therethrough such that they are offset with respect to one another in a lengthwise direction when joined. As a consequence, seaming loops at one widthwise edge of the first base fabric coincide with a non-seam region of the second base fabric, and seaming loops at one widthwise edge of the second base fabric coincide with a non-seam region of the first base fabric. When joined into endless form, the first base fabric is an outer base fabric, and the second base fabric is an inner base fabric. At least one extra cross-machine-direction (CD) yarn is woven with at least two of the following: (a) the outer side of the seaming loops of at least one widthwise edge of the outer base fabric; (b) the inner side of the seaming loops of at least one widthwise edge of the outer base fabric; (c) the outer side of the seaming loops of at least one widthwise edge of the inner base fabric; and (d) the inner side of the seaming loops of at least one widthwise edge of the inner base fabric.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to the papermaking arts. More specifically, 
the present invention is a papermaker's fabric of the on-machine-seamable 
(OMS.RTM.) variety, such as an OMS.RTM. press fabric for the press section 
of a paper machine. 
2. Description of the Prior Art 
During the papermaking process, a fibrous cellulosic web is formed by 
depositing a fibrous slurry, that is, an aqueous dispersion of cellulose 
fibers, on a moving forming fabric in the forming section of a paper 
machine. A large amount of water is drained from the slurry through the 
forming fabric during this process, leaving the fibrous cellulosic web on 
the surface of the forming fabric. 
The newly formed cellulosic web proceeds from the forming section to a 
press section, which includes a series of press nips. The fibrous 
cellulosic web passes through the press nips supported by a press fabric, 
or, as is often the case, between two press fabrics. In the press nips, 
the fibrous cellulosic web is subjected to compressive forces which 
squeeze water therefrom, and which adhere the cellulose fibers in the web 
to one another to turn the fibrous cellulosic web into a paper sheet. The 
water is accepted by the press fabric or fabrics and, ideally, does not 
return to the paper sheet. 
The paper sheet finally proceeds to a dryer section, which includes at 
least one series of rotatable dryer drums or cylinders, which are 
internally heated by steam. The newly formed paper sheet is directed in a 
sinuous path sequentially around each in the series of drums by a dryer 
fabric, which holds the paper sheet closely against the surfaces of the 
drums. The heated drums reduce the water content of the paper sheet to a 
desirable level through evaporation. 
It should be appreciated that the forming, press and dryer fabrics all take 
the form of endless loops on the paper machine and function in the manner 
of conveyors. It should further be appreciated that paper manufacture is a 
continuous process which proceeds at considerable speed. That is to say, 
the fibrous slurry is continuously deposited onto the forming fabric in 
the forming section, while a newly manufactured paper sheet is 
continuously wound onto rolls after it exits from the dryer section. 
Referring, for the moment, specifically to press fabrics, it should be 
recalled that, at one time, press fabrics were supplied only in endless 
form. This is because a newly formed paper sheet is extremely susceptible 
to marking in the press nip by any nonuniformity in the press fabric or 
fabrics. An endless, seamless fabric, such as one produced by the process 
known as endless weaving, has a uniform structure in both its longitudinal 
(machine) and transverse (cross-machine) directions. A seam, such as a 
seam which may be used to close the press fabric into endless form during 
installation on a paper machine, represents a discontinuity in the uniform 
structure of the press fabric. The use of a seam, then, greatly increases 
the likelihood that the paper sheet will be marked in the press nip. 
It follows, then, that the seam region of any workable on-machine-seamable 
(OMS.RTM.) press fabric must behave under load, that is, under compression 
in a press nip, like the rest of the press fabric, and must have the same 
permeability to water and to air as the rest of the press fabric, in order 
to prevent the periodic marking of the paper product being manufactured by 
the seam region. OMS.RTM. is a registered trademark of Albany 
International Corp. 
Despite the considerable technical obstacles presented by these 
requirements, it remained highly desirable to develop an 
on-machine-seamable (OMS.RTM.) press fabric, because of the comparative 
ease and safety with which it could be installed on the press section. 
Ultimately, these obstacles were overcome with the development of press 
fabrics having seams formed by providing seaming loops on the crosswise 
edges of the two ends of the fabric. The seaming loops themselves are 
formed by the machine-direction (MD) yarns of the fabric. A seam is formed 
by bringing the two ends of the press fabric together, by interdigitating 
the seaming loops at the two ends of the fabric, and by directing a 
so-called pin, or pintle, through the passage defined by the 
interdigitated seaming loops to lock the two ends of the fabric together. 
Needless to say, it is much easier and far less time-consuming to install 
an OMS.RTM. press fabric, than it is to install an endless press fabric, 
on a paper machine. 
There are several methods for producing a press fabric that can be joined 
on the paper machine with such a seam. One method is to flat-weave the 
fabric, in which case the warp yarns are the machine-direction (MD) yarns 
of the press fabric. To form the seaming loops, the warp ends are woven 
some distance back into the fabric body in a direction parallel to the 
warp yarns. Another technique, far more preferable, is a modified form of 
endless weaving, which normally is used to produce an endless loop of 
fabric. In modified endless weaving, the weft, or filling, yarns are 
continuously woven back and forth across the loom, in each passage forming 
a loop on one of the edges of the fabric being woven by passing around a 
loop-forming pin. As the weft yarn, or filling yarn, which ultimately 
becomes the MD yarn in the press fabric, is continuous, the seaming loops 
obtained in this manner are stronger than any that can be produced by 
weaving the warp ends back into the ends of a flat-woven fabric. In still 
another method, a fabric is woven endless, and the endless loop of fabric 
thereby obtained is flattened and given the form of two fabric layers 
joined to one another at two widthwise ends of the flattened loop. One or 
more widthwise yarns are then removed from each of the two widthwise ends 
to produce a short gap defined by the freed, that is, the newly unwoven 
portions of, lengthwise yarns at each end. These unwoven portions of the 
lengthwise yarns are then used as seaming loops when the two widthwise 
ends are brought together as described above. 
Generally, the manufacture of an on-machine-seamable (OMS.RTM.) press 
fabric includes the attachment of a staple fiber batt to one or both sides 
thereof. The attachment may be effected by a process called needling 
(fiber locking) or by hydroentangling, while the OMS.RTM. fabric is joined 
in endless form. Once the desired amount of staple fiber batt has been 
attached, the loop-forming pin or pintle is removed to place the OMS.RTM. 
press fabric into flat form for shipment and eventual installation on a 
paper machine. At this time, the staple fiber batt must be cut in the 
vicinity of the seam to completely separate the two ends of the OMS.RTM. 
press fabric from one another. Often, the staple fiber batt is cut in a 
manner that enables it to form a flap over the seaming loops when the 
OMS.RTM. press fabric is rejoined into endless form. In this way, the seam 
region is practically indistinguishable from the rest of the 
paper-supporting side of the press fabric. 
On the other side, the "roll" side, of the press fabric, however, some 
staple fiber batt must be removed from the seaming loops to facilitate the 
later passage of a pintle therethrough. The removal of this generally 
small amount of staple fiber batt, nevertheless, makes the seam region 
slightly more permeable to air and water than the rest of the press 
fabric. This difference in water permeability, or flow resistance, perhaps 
ever so slight, is enough to cause sheet marking in some situations. 
Several approaches to solve this problem have been taken. One approach 
involves the use of stuffer yarns with the pintle when the OMS.RTM. press 
fabric is being joined into endless form on the paper machine. In another 
approach, an OMS.RTM. press fabric comprises two on-machine-seamable base 
fabrics, one fitting inside the loop of the other, the two base fabrics 
being laminated to one another during the needling process. The seam 
regions of the inner and outer base fabrics are offset slightly with 
respect to one another, so that the seam region of each will coincide with 
a non-seam region of the other. Once the desired amount of staple fiber 
batt has been attached to the inner and/or outer surfaces of the laminated 
base fabrics, the loop-forming pin or pintle of each on-machine-seamable 
base fabric is removed to place the OMS.RTM. press fabric into flat form 
for shipment and eventual installation on a papermachine. At this time, 
the staple fiber batt must be cut in the vicinity of the seam in the outer 
of the two on-machine-seamable base fabrics to completely separate the two 
ends of the OMS.RTM. press fabric from one another. As above, the staple 
fiber batt may be cut in a manner that enables it to form a flap over the 
seaming loops when the OMS.RTM. press fabric is rejoined into endless 
form. Some of the staple fiber batt must also be removed from the seaming 
loops of both the inner and outer on-machine-seamable base fabrics to 
facilitate the later passage of pintles therethrough. 
In yet another approach, disclosed in U.S. Pat. Nos. 5,476,123 and 
5,531,251 to Rydin, one or more extra CD yarns are woven with the seaming 
loops of at least one end of a base fabric of an on-machine-seamable press 
fabric. The extra yarn or yarns are woven only with those portions of the 
seaming loops that are on one side of the fabric, that side preferably 
being the paper-supporting side. The extra CD yarn or yarns form an 
extension of the CD yarn system of the base fabric at the seaming loop or 
loops, conforming the seam region more closely to the rest of the base 
fabric, so that staple fiber batt will be better anchored to the seam 
region and so that the possibility of sheet marking by the seam region 
will be reduced. 
The last approach has also been combined with that set forth immediately 
above in OMS.RTM. press fabrics having two on-machine-seamable base 
fabrics laminated to one another during the needling process, one base 
fabric again fitting inside the loop of the other. In this hybrid 
approach, the outer base fabric incorporates the invention disclosed in 
U.S. Pat. Nos. 5,476,123 and 5,531,251, the teachings of both of which are 
incorporated herein by reference. 
All of these approaches are designed to compensate for the differences 
between the water permeability or flow resistance of the seam region of an 
OMS.RTM. press fabric and the rest or body of the press fabric. However, 
none of these approaches has yielded completely satisfactory results for 
all press types and positions and for all paper grades. 
The present invention represents an alternative approach toward solving 
this problem. 
SUMMARY OF THE INVENTION 
Accordingly, the present invention is an on-machine-seamable papermaker's 
fabric which comprises a first base fabric and a second base fabric. 
The first base fabric has a system of first machine-direction (MD) yarns 
and a system of first cross-machine-direction (CD) yarns, the first MD 
yarns being bound to the first CD yarns. The first base fabric has a 
rectangular shape with a length, a width, two lengthwise edges, two 
widthwise edges, a first side and a second side. The first MD yarns form 
first seaming loops along each of the two widthwise edges of the first 
base fabric. 
The second base fabric, similarly, has a system of second MD yarns and a 
system of second CD yarns, the second MD yarns being bound to the second 
CD yarns. The second base fabric likewise has a rectangular shape with a 
length, a width, two lengthwise edges, two widthwise edges, a first side 
and a second side. The second MD yarns form second seaming loops along 
each of the two widthwise edges of the second base fabric. 
The first and second base fabrics have substantially equivalent lengths and 
widths, and are joined to one another by at least one layer of staple 
fiber batt entangled therethrough. When so joined, the second side of the 
first base fabric adjoins the first side of the second base fabric. The 
first and second base fabrics are also offset with respect to one another 
in a lengthwise direction. As a consequence, the first seaming loops at 
one widthwise edge of the first base fabric coincide with a non-seam 
region of the second base fabric, and the second seaming loops at one 
widthwise edge of the second base fabric coincide with a non-seam region 
of the first base fabric. 
In accordance with the present invention, at least one extra CD yarn is 
woven with at least two of the following: 
a) the first side of the first seaming loops of at least one widthwise edge 
of the first base fabric; 
b) the second side of the first seaming loops of at least one widthwise 
edge of the first base fabric; 
c) the first side of the second seaming loops of at least one widthwise 
edge of the second base fabric; and 
d) the second side of the second seaming loops of at least one widthwise 
edge of the second base fabric. 
The first base fabric may be the outer base fabric, and the second base 
fabric the inner base fabric, when the present papermaker's fabric is 
joined into the form of an endless loop. In such a situation, the first 
sides of the first and second base fabrics and their respective first and 
second seaming loops face outward with respect to the endless loop. It 
follows that the second sides of the first and second base fabrics and 
their respective first and second seaming loops face inward with respect 
to the endless loop. 
The on-machine-seamable papermaker's fabric is joined into endless form by 
interdigitating the first seaming loops at the two widthwise edges of the 
first base fabric and by direction a first pintle through the passage 
defined by the interdigitated first seaming loops to form a first seam, 
and by interdigitating the second seaming loops at the two widthwise edges 
of the second base fabric and by directing a second pintle through the 
passage defined by the interdigitated second seaming loops to form a 
second seam. The extra CD yarns woven with the seaming loops as set forth 
above improve the integrity of the seams, especially by providing improved 
staple fiber batt retention in the vicinities of the seams, and reduce the 
marking of fibrous webs by the seams. 
The present invention will now be described in more complete detail, with 
frequent reference being made to the drawing figures identified as follows 
.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Turning now specifically to the figures, FIG. 1 is a schematic perspective 
view of an on-machine-seamable papermaker's fabric 10. The fabric takes 
the form of an endless loop once its two ends 12,14 have been joined to 
one another at seam 16. 
FIG. 2 is a cross-sectional view, taken as indicated by line 2--2 in FIG. 
1, of an on-machine-seamable papermaker's fabric 20 of the prior art. 
Papermakers' fabric 20 is of the variety having two on-machine-seamable 
base fabrics 30, 40. Outer base fabric 30 surrounds inner base fabric 40, 
the latter being joined into endless form within the endless-loop form of 
the former. Inner base fabric 40 is of substantially the same length as 
outer base fabric 30, so that seam 42 is closed by directing pintle 44 
therethrough at the same time as, or immediately before or after, seam 32 
is closed by directing pintle 34 therethrough. Inner base fabric 40 and 
outer base fabric 30 are joined to one another by needling one or more 
layers of staple fiber batt 50 into at least one of the base fabrics 30, 
40 to join the two base fabrics 30, 40 to one another. For the sake of 
clarity, staple fiber batt 50 is shown in only a portion of FIG. 2, but it 
should be understood that it joins the inner and outer base fabrics 40, 30 
to one another at all points except the immediate region of the seams 32, 
42, from which batt 50 is removed during processing to facilitate the 
meshing of the seaming loops 52, 54. Staple fiber batt 50 may comprise 
staple fibers of any polymeric resin used in the production of 
papermachine clothing, but are preferably of a polyamide resin. 
Outer base fabric 30 is woven from longitudinal, or machine-direction (MD), 
yarns 36 and transverse, or cross-machine direction (CD), yarns 38. MD 
yarns 36 form seaming loops 5i which are interdigitated and joined to one 
another by directing pintle 34 through the passage defined by the 
interdigitated seaming loops 52 to form seam 32. 
In like manner, inner base fabric 40 is woven from longitudinal, or 
machine-direction (MD), yarns 46 and transverse, or 
cross-machine-direction (CD), yarns 48. MD yarns 46 form seaming loops 54 
which are interdigitated and joined to one another by directing pintle 44 
through the passage defined by the interdigitated seaming loops 54 to form 
seam 42. 
It will be recognized in FIG. 2 that both the inner and outer base fabrics 
40, 30 are flat-woven, wherein seaming loops 52, 54 are formed by turning 
back ends of warp yarns at the widthwise edges of the inner and outer base 
fabrics 40, 30 and by weaving the ends back into the respective fabrics. 
As depicted in FIG. 2, MD yarns 36, 46 are the warp yarns of the outer and 
inner base fabrics 30, 40, respectively. It should be understood, however, 
that either one or both of the inner and outer base fabrics 40, 30 may be 
woven by a modified endless weaving technique, wherein weft yarns weave 
continuously back and forth across the loom, form seaming loops by weaving 
around a loop-forming pin, and ultimately become the MD yarns of the 
fabric. 
MD yarns 36, CD yarns 38, MD yarns 46 and CD yarns 48 may each be of any of 
the yarn types used to weave papermachine clothing. That is to say, 
monofilament yarns, which are monofilament strands used singly, or 
plied/twisted yarns, in the form of plied monofilament or plied 
multifilament yarns may be used as any of these yarns. Further, MD yarns 
36, CD yarns 38, MD yarns 46 and CD yarns 48 may each be the coated yarns 
shown in commonly assigned U.S. Pat. Nos. 5,204,150 and 5,391,419, the 
teachings of both of which are incorporated herein by reference. 
Further, the filaments comprising MD yarns 36, CD yarns 38, MD yarns 46 and 
CD yarns 48 are extruded from synthetic polymeric resin materials, such as 
polyamide, polyester, polyetherketone, polypropylene, polyaramid, 
polyolefin and polyethylene terephthalate (PET) resins, and incorporated 
into yarns according to techniques well-known in the textile industry and 
particularly in the papermachine clothing industry. 
Pintles 34, 44 may be single strands of monofilament; multiple strands of 
monofilament; multiple strands of monofilament untwisted about one 
another, or plied, twisted, braided or knitted together; or of any of the 
other pintle types used to join pin seams in papermachine clothing. The 
pintles 34, 44 may be extruded from synthetic polymeric resin materials, 
such as those listed in the preceding paragraph. 
It will be observed in FIG. 2 that seam 32 in outer base fabric 30 is 
offset longitudinally from seam 42 in inner base fabric 40. As a 
consequence, the region of seam 32 in outer base fabric 30 coincides with 
a non-seam region of the inner base fabric 40. In like manner, the region 
of seam 42 in inner base fabric 40 coincides with a non-seam region of the 
outer base fabric 30. This longitudinal offsetting is done to minimize 
sheet marking and to facilitate seaming on the papermachine. 
In addition, the outer base fabric 30 of the prior-art papermaker's fabric 
20 shown in FIG. 2 is produced in accordance with the invention shown in 
U.S. Pat. Nos. 5,476,123 and 5,531,251, the teachings of both of which are 
incorporated herein by reference. As shown more clearly in FIG. 6, a 
schematic perspective view of the seaming loops 200 of a fabric 190 
produced in accordance with the invention shown in these patents an extra 
CD yarn 56 is woven with the outer portions of each of the seaming loops 
52 as extra CD yarn 202 is woven with the outer portions of each of the 
seaming loops 200 in FIG. 6. The extra CD yarns 56 form an extension of 
the system of CD yarns 38 of the outer base fabric 30 at the seaming loops 
52, conforming the seam 32 more closely to the rest of the outer base 
fabric 30, so that staple fiber batt 50 will be better anchored to the 
region of seam 32 and so that the possibility of sheet marking by the seam 
32 will be reduced. 
Despite the presence of extra CD yarns 56, problems with sheet marking and 
seam integrity have persisted with the use of papermaker's fabric 20. The 
present invention is intended to provided a solution to these problems. 
To that end, FIG. 3 is a cross-sectional view, analogous to that provided 
in FIG. 2, of a first embodiment of the on-machine-seamable papermaker's 
fabric 60 .of the present invention. 
Much of the description of the prior-art papermaker's fabric 20 shown in 
FIG. 2 applies to papermaker's fabric 60 shown in FIG. 3, as well as to 
papermaker's fabrics 100, 140 shown in FIGS. 4 and 5, respectively. 
Papermaker's fabric 60 has an outer base fabric 70 which surrounds an 
inner base fabric 80, the latter being joined into endless form within the 
endless-loop form of the former. Seam 82 of inner base fabric 80 is closed 
by directing pintle 84 therethrough at the same time as seam 72 of outer 
base fabric 70 is closed by directing pintle 74 therethrough. Inner base 
fabric 80 and outer base fabric 70 are joined to one another by needling 
one or more layers of staple fiber batt 90 into at least one of the base 
fabrics 70, 80 to join the two base fabrics 70, 80 to one another. Again, 
staple fiber batt 90 is shown in only a portion of FIG. 3. 
Outer base fabric 70 is woven from MD yarns 76 and CD yarns 78. MD yarns 76 
form seaming loops 92 which are interdigitated and joined to one another 
by directing pintle 74 through the passage defined by the interdigitated 
seaming loops 92 to form seam 72. Inner base fabric 80 is woven from MD 
yarns 86 and CD yarns 88. MD yarns 86 form seaming loops 94 which are 
interdigitated and joined to one another by directing pintle 84 through 
the passage defined by the interdigitated seaming loops 94 to form seam 
82. Outer base fabric 70 and inner base fabric 80 may be of different 
weave patterns. 
MD yarns 76, CD yarns 78, MD yarns 86 and CD yarns 88 may each be of any of 
the yarn types used to weave papermachine clothing, and may include 
filaments extruded from any of the synthetic polymeric resin materials 
used for the production of yarns for papermachine clothing, both of which 
have been identified above in the description of the prior-art 
papermaker's fabric 20 shown in FIG. 2. 
Pintles 74, 84 may also be as set forth above, and seam 72 in outer base 
fabric 70 is offset longitudinally (in the machine direction) from seam 82 
in inner base fabric 80. 
In accordance with this first embodiment of the present invention, both the 
outer base fabric 70 and the inner base fabric 80 are produced in 
accordance with the inventions shown in U.S. Pat. Nos. 5,476,123 and 
5,531,251. That is to say, an extra CD yarn 96 is woven with the outer 
portions of each of the seaming loops 92 of the outer base fabric 70 and 
an extra CD yarn 98 is woven with the outer portions of each of the 
seaming loops 94 of the inner base fabric 80. 
In the second embodiment of the present invention, shown in cross section 
in FIG. 4, papermaker's fabric 100 has an outer base fabric 110 and an 
inner base fabric 120. Outer base fabric 110 has a seam 112 closed by 
pintle 114, while inner base fabric 120 has a seam 122 closed by pintle 
124. Outer base fabric 110 includes seaming loops 132, and inner base 
fabric 120 includes seaming loops 134. 
In accordance with this second embodiment of the present invention, an 
extra CD yarn 136 is woven with the outer portions of each of the seaming 
loops 132 of the outer base fabric 110, and an extra CD yarn 138 is woven 
with the inner portions of each of the seaming loops 132 of the outer base 
fabric 110. 
In the third embodiment of the present invention, shown in cross section in 
FIG. 5, papermaker's fabric 140 has an outer base fabric 150 and an inner 
base fabric 160, both of which have extra CD yarns in the same manner as 
outer base fabric 110 of papermaker's fabric 100 in FIG. 4. Outer base 
fabric 150 has a seam 152 closed by pintle 154, while inner base fabric 
160 has a seam 162 closed by pintle 164. Outer base fabric 150 includes 
seaming loops 172, and inner base fabric 160 includes seaming loops 174. 
In accordance with this third embodiment, an extra CD yarn 176 is woven 
with the outer portions of each of the seaming loops 172 of the outer base 
fabric 150, and an extra CD yarn 178 is woven with the inner portions of 
each of the seaming loops 172. At the same time, an extra CD yarn 180 is 
woven with the outer portions of each of the seaming loops 174 of the 
inner base fabric 160, and an extra CD yarn 182 is woven with the inner 
portions of each of the seaming loops 172. 
Extra CD yarns 96, 98, 136, 138, 176, 178, 180, 182 may also be of any of 
the types used to weave papermachine clothing. That is to say, 
monofilament yarns or plied/twisted yarns, in the form of plied 
monofilament or plied multifilament yarns, may be used as any of these 
yarns. Extra CD yarns 96, 98, 136, 138, 176, 178, 180, 182 may also be the 
coated yarns shown in commonly assigned U.S. Pat. Nos. 5,204,150 and 
5,391,419, the teachings of both of which are incorporated herein by 
reference. Further, the filaments comprising extra CD yarns 96, 98, 136, 
138, 176, 178, 180, 182 may be extruded from synthetic polymeric resin 
materials, such as polyamide, polyester, polyetherketone, polypropylene, 
polyaramid, polyolefin and polyethylene terephthalate (PET) resins, and 
incorporated into yarns according to techniques well-known in the textile 
industry and particularly in the papermachine clothing industry. The extra 
CD yarns 96, 98, 136, 138, 176, 178, 180, 182 may also be of a polymeric 
resin material having a lower melting point than the other yarns in the 
papermaker's fabrics 60, 100, 140 to provide by heating a more efficient 
fiber anchorage in the seam region. They may also have cross sections of 
round, flat or other geometric shapes. 
While base fabrics 70, 80, 110, 120, 150, 160 are shown in FIGS. 3, 4 and 5 
as being of a two-layer weave, it should be understood that each could be 
woven in any of the weave patterns, such as, for example, one-, two- or 
three-layer weave patterns, used by those of ordinary skill in the art to 
weave paper machine clothings. FIG. 7 is a cross-sectional view of a 
single-layer weave 210 which may be used in the practice of the present 
invention, and FIG. 8 is a cross-sectional view of a three-layer weave 220 
useful for this same purpose. Further, one or both of the base fabrics in 
any of the papermaker's fabrics 60, 100, 140 may be a fabric of the 
variety shown in commonly assigned U.S. Pat. No. 4,979,543 to Moriarty et 
al., the teachings of which are incorporated herein by reference. 
In U.S. Pat. No. 4,979,543, a press fabric having a plurality of layers of 
machine-direction and cross-machine-direction yarns is shown. The yarns 
for each layer are oriented in parallel with respect to each other and 
perpendicular with respect to the yarns of immediately adjacent layers. 
The yarns of one layer do not bind the yarns of adjacent layers. Separate 
binder yarns bind the layers together. FIG. 9, which is based upon FIG. 2 
of U.S. Pat. No. 4,979,543, is a cross-sectional view of a fabric 230 
having separate binder yarns 232. 
The fabric defines two machine-direction oriented edges and two 
cross-machine-direction oriented edges, whereby, at each 
cross-machine-direction oriented edge, certain machine-direction yarns 
extend from one layer a distance sufficient to form a loop and then return 
to the same cross-machine-direction oriented edge into another layer of 
machine-direction yarns. 
A staple fiber batt may be entangled into the fabric by needling. Where 
this is the case, the needling may actually break the separate binder 
yarns, which are generally thinner than the structural machine-direction 
and cross-machine-direction yarns. As a consequence, the staple fiber 
batt, needled into the cross-crossed structure of the structural yarns, 
binds the fabric together. 
The present invention provides a more closed seam region having a reduced 
tendency to mark a fibrous cellulosic web being dewatered. The presence of 
the extra CD yarns woven with the seaming loops provides additional 
anchoring between the two bases in the seam area, thereby inhibiting 
delamination. Further, the extra CD yarns enable additional staple fiber 
batt to anchor on the inner portions of the seam region of the inner base 
fabric, thereby improving the abrasion resistance of the seam region. As a 
consequence, the present invention provides a papermaker's fabric having 
improved seam integrity and less seam marking than those of the prior art. 
Modifications to the above would be obvious to those of ordinary skill in 
the art, but would not bring the invention so modified beyond the scope of 
the appended claims.