In order to reduce the rate of wear of a papermakers fabric having a loop seam, especially in the region of such loop seam, a protective facing of additional cross-machine direction yarns is provided at the intended roller side of the fabric. The additional yarns are woven integrally with the fabric and are arranged to float at the face of the fabric, and define a surface to the fabric as a whole which is displaced outwardly of the fabric in relation to the surface of the basic weave structure.

The invention concerns papermakers fabric, and has more particular 
reference to a method for improving the abrasion resistance thereof. 
In the papermaking process, a liquid suspension of cellulosic fibres is 
applied to a moving openwork mesh through which excess liquid is drained 
to give a moist web of cellulosic fibres and such filler or other 
materials as are appropriate to the paper being produced, the web 
subsequently passing through a roller nip whereat further liquid is 
removed, and eventually passing over heated rollers whereat the paper is 
dried. 
The openwork mesh originally comprised a woven metal mesh, particularly 
phosphor bronze, but for some years past synthetic materials have been 
used and `wires` of synthetic textile material are now commonplace. 
One problem met with in connection with all woven wires has been the 
necessity to provide such wires in an endless belt form on the papermaking 
machine, this requiring that the wire be woven endless and applied to the 
machine in such form or that the wire be woven flat and the ends joined 
before or after application to the machine. 
The present invention is directed to flat woven wires and is particularly 
concerned with a wire which can be easily joined after its mounting into 
the paper machine. 
The formation of a seam by weaving the machine direction yarns back into 
the cloth thereby leaving a series of loops at either end of the fabric is 
well known. One major problem which has been found in practice with using 
a warp loop seam is that, as it is subjected to abrasion in use, the loops 
quickly disintegrate and the effective life of the fabric is 
correspondingly shortened. 
It is an object of this invention to produce a fabric in which the problem 
of abrasion or seam failure is of reduced proportions, and thus, in 
accordance with the invention there is proposed a flat-woven papermakers 
fabric having integrally formed warp loops including additional 
cross-machine direction yarns at one face thereof and at least in the 
region of the fabric ends, the said additional cross-machine direction 
yarns lying or extending outwardly of the plane of the seam-forming 
elements at such face and floating at such face in relation to the normal 
weave structure thereof.

Referring now to the drawings, and particularly to FIGS. 1 and 2 thereof, a 
flat-woven papermakers fabric of known duplex or semi-duplex weave 
structure comprising warp yarns 21 and weft yarns 22, having warp loops 23 
extending from the ends thereof whereby such ends might be joined together 
to form a seam, further includes additional weft yarns 24 at one or other 
face of the fabric, such yarns 24 floating at the surface of the fabric 
and being woven with, say, every twelfth warp yarn, and, in the embodiment 
illustrated, being provided on the basis of one additional weft yarn for 
each weft yarn ordinarily present in the structure. The additional weft 
yarns 24 will generally be provided throughout the full longitudinal 
extent of the fabric and will ordinarily be selected, as to their 
characteristics, to reduce wear during use of the fabric on a papermaking 
machine. However, it may be found sufficient, as regards protecting the 
region of the seam against wear, to provide additional weft yarns only in 
the region of the fabric ends, the extreme additional weft yarn in either 
case, being closely adjacent to such ends. The yarns 24 will preferably 
have, for example, an inherent high wear-resistance or an anit-slip 
characteristic, although such characteristics may be derived from a 
suitable resin or other treatment to which the yarn is subjected. It is 
not necessary, however, that the additional weft yarns have a 
wear-resistance beyond that of the other yarns of the fabric since the 
invention relies upon the fact that, whereas when a warp loop seam is made 
on the end of the fabric the warp loops lie substantially in the same 
plane as the body of the fabric, the provision of additional weft yarns as 
hereinproposed will result in the backs of the loops being in a plane A 
displaced inwardly of the total fabric in relation to the plane B of the 
back of such total fabric, the seam thereby being protected by the 
additional weft yarns, and particularly by the mass of such additional 
weft yarns. 
The additional weft yarns will ordinarily be of a diameter (or equivalent) 
not greater than that of the weft yarns ordinarily present in the fabric, 
and may comprise yarns conventionally used in the art. Thus, resin coated 
monofilament or multifilament synthetic yarns, uncoated such yarns, glass 
yarns or metal yarns may be utilised. 
The warp loops 23 are preferably formed in accordance with the disclosure 
of the specification of prior U.S. Pat. No. 4,026,331 wherein weft yarns 
are removed from the end of the fabric to give a weft free zone, selected 
ones of the warp yarns in the region of the weft free zone are shortened 
while the remaining warp yarns are folded back into register with 
respective ones of the shortened warp yarns selectively about one or other 
of the two axes extending transversely of the fabric to form loops spaced 
transversely of the fabric, and reintroducing weft yarns into the 
resultant weftless end of the fabric, the crimp pattern present in the 
uncut warp yarns being compatible with the overall crimp pattern of the 
volume of the fabric when such yarns are folded back about one or other of 
the said axes. 
A typical fabric structure is shown in FIGS. 3 and 4, FIG. 3 being a weave 
peg-plan showing the shedding of the warp yarns for a pattern repeat of 
the total structure widthwise of the fabric of twelve ends and lengthwise 
of the fabric of sixteen picks and FIGS. 4a to 4l showing the relationship 
between the individual ones of the warp yarns 1 to 12 of the peg-plan of 
FIG. 3 and the individual weft yarns 1 to 16 of such peg-plan. 
Thus, as can be seen from the right hand column of the peg-plan and from 
FIG. 4a, warp yarn 1 is lifted for picks 1 to 3, is lowered for pick 4, 
raised again for pick 5, lowered for picks 6 to 12, raised for pick 13 and 
then lowered for picks 14 to 16, the yarn then being raised for picks 1 to 
3 of the next repeat. 
Similarly, the peg-plan and FIG. 4b show that warp yarn 2 is lifted for the 
insertion of weft yarn 1, lowered for picks 2 to 4, raised again for picks 
5 and 6, lowered for picks 7 and 8, raised for pick 9, and then lowered 
for picks 10 to 16 before being raised again for pick 1 of the next 
repeat. 
The paths of warp yarns 3 to 12 are shown in the relevant columns of the 
peg-plan of FIG. 3 and in FIGS. 4c to 4l, respectively. 
Reference to FIG. 3 will show that each of the additional weft yarns, which 
yarns comprise wefts 3, 4, 7, 8, 11, 12, 15 and 16 of the peg-plan, binds 
with the fabric as formed by the warp yarns 1 to 12 and the remaining weft 
yarns only once in each three pattern repeats of the base weave in the 
weftwise direction of the fabric. 
It can be clearly seen from FIGS. 1 and 2 of the drawings how the plane of 
the cross machine direction yarns, as constituted by the additional weft 
yarns, lies substantially outside that of the machine direction loops 
forming the seam. 
The invention is not restricted to the exact features of the embodiment 
herein described and illustrated, since alternatives will readily present 
themselves to one skilled in the art. Thus, whilst it is found preferable 
to provide additional weft yarns in like numbers in relation to the weft 
yarns ordinarily present, a lesser density of such additional weft yarns 
may be found satisfactory in some circumstances, although a ratio of 
additional weft yarns to weft yarns oridinarily present of less than 1 to 
2 is thought unlikely to provide a substantial improvement in wear 
resistance. The extent to which the additional weft yarns float at the 
fabric surface may vary to suit particular circumstances, but ideally the 
additional weft yarns float over three repeats of the base weave, although 
arrangements wherein the float is over two or more than three such repeats 
are satisfactory. 
The invention is applicable both to forming fabrics and to dryer fabrics, 
and may be used in the context of both single layer and multi-layer 
fabrics. 
In the case of a papermakers fabric for use as a paper machine wire or a 
forming fabric (which expressions are, in this specification, to be 
considered to be synonymous), the additional weft yarns will be provided 
at the intended roller side of the fabric, whereas, bearing in mind that 
advantage has been found to stem from the provision of additional weft 
yarns at the paper side of a dryer fabric in that a better paper-forming 
surface is obtained by so doing, in the case of dryer fabrics the 
additional weft yarns will ordinarily be provided at such paper side and 
will preferably comprise spun yarns.