WO1979000026A1

WO1979000026A1 - A method of producing a seam in double-layer forming fabrics

Info

Publication number: WO1979000026A1
Application number: PCT/SE1978/000006
Authority: WO
Inventors: I Strandly
Original assignee: Nordiskafilt Ab
Priority date: 1977-07-05
Filing date: 1978-06-22
Publication date: 1979-01-25
Also published as: GB2035890B; MX148934A; EP0006866A1; GB2035890A; CA1093940A; NZ187738A; AU3778278A; FR2450299B1; FI59838C; FI782024A; FI59838B; AU521640B2; FR2450299A1; JPS5438980A

Abstract

A method of providing a row of loops at each end of a forming fabric, a filter cloth or a similar fabric, said fabric comprising two layers of weft threads with the threads positioned in pairs substantially one on top of the other and warp threads interconnecting said weft layers where the weft threads are permanently removed in a first zone (4) closest to one end edge of said fabric and temporarily removed in a second zone (5) adjacent to said first zone, where a number of weft threads corresponding to the temporarily removed weft threads together with at least one folding thread (7, 8) are drawn in as a warp in a joining machine similar to a loom, and where one of said folding threads is coarse (8) and temporarily replaces the cable intended finally to interconnect the two fabric ends. The method comprises different proceedings depending upon the position of the warp threads in accordance with the weave pattern when they cross the weft threads of the outermost pair preceding the loop itself.

Description

A Method of Providing a Seam in Double-Layer Forming Fabrics

BACKGROUND OF THE INVENTION

Most forming fabrics within the paper, cellulose and asbestos-cement industries must be woven endless. As a rule, the fabrics are made in endless form during the very wea¬ ving while using the so-called tubular weaving technique, or else the fabric ends are interconnected during the manu¬ facture, e.g. by splicing. Usually, the splicing can be effected only by the manufacturer during the manufacture of the fabric. On account of the machine construction, some forming fabrics may be end joined only in connection with their mounting in the machine, and in such cases the fabrics must be provided u/ith some suitable joint or seam fastener. Fabric end jointing in immediate connection ωith the installation in the machine is most commonly used in the case of dryer felts and dryer cloths. In these types of products so called belt fasteners are used. The loops of these fasteners are of metal and usually U-shaped. They are attached either on the cloth itself or on sepa¬ rate fastener strips which are sewn onto the cloth ends. In addition to the dryer section there are, however, several other positions in which it is necessary to de_¬ liver an open cloth the ends of which are to be interconnec- ted directly in the machine. For instance, in Inverform machines the cloth does not as a rule lend itself to end¬ less mounting. As belt fasteners are unsuitable for use to join together forming fabrics and certain filter types, a number of alternative possibilities have been developed

during recent years to replace the belt fasteners. The one that has found most practical use is the so called loop seam wherein the warp thread ends are removed and there¬ after are re-introduced into the weave,after having been formed into locking loops at the cloth end. The locking loops at both ends are then interconnected during the cloth mounting by means of one or several fastening wires A seam of this kind, performed in a single-layer structur is described for instance in the Swedish published Speci- fication No. 322 980.

In forming fabrics, it is important that the seam are has approximately the same openness as the rest of the fabric in order to avoid too pronounced marking and to re duce the risk of web breaks. It is likewise important tha the locking loops are designed so as to avoid that they themselves or the warp threads in connection therewith are exposed to more wear than the rest of the fabric.

In later years, double-layer forming fabrics comprisi two layers of weft threads and warp threads interconnecti these layers have found increasingly wide applications.

Examples of fabrics of this kind are described in the two Swedish Published Specifications Nos. 366 353 and 385 486 Attempts have been made earlier to provide also the type of fabrics defined in these publications with loop seams, thereby making them useful in positions where the fabrics must be jointed directly in the machine. On account prima of their non-symmetric pattern, double-layer fabrics lack the natural properties that would make them suitable for provision of loop seams thereon. The reason therefor is that when the warp threads have formed a loop and are to be re-introduced into the cloth, the re-intfcoduction must be performed in a manner ensuring that the crimp of the thread conforms with the pattern of the cloth. In the pas many loops therefore were either too small, thus making i impossible to pass a locking wire through them, or else t large, whereby openings formed between the locking wire and the rest of the fabric,causing increased marking and

OMPI Wlrø also risks of web breaks. Another disadvantage is that the warp thread in connection with the loop formations is ex¬ posed on the wear side of the fabric, resulting in in¬ creased wear. SUMMARY OF THE INVENTION

The present invention relates to a method of providing a row of loops at each end of a forming fabric, filter cloth or similar weave of a kind comprising two layers of weft threads with the threads positioned in pairs substan- tially one on top of the other, and warp threads inter¬ connecting the weft layers, said rows of loops intended to be interconnected by a locking wire to form an endless fabric, web.

The method of the invention is characterised in removing permanently the weft threads in a first zone closest to one end edge of said fabric, removing temporarily the weft threads in a second zone adjacent said first zone, arranging said temporarily removed weft threads, alternatively a corresponding number of weft threads, together with one coarse folding wire and possibly also one or several thin folding wires as a warp in a sewing machine similar to a loom, of a kind known per se, wherein said coarse wire temporarily replaces said locking wire intended finally to interconnect the two fabric ends, where two warp thread ends in succession in accordance with the pattern repeat bind between the threads of the outermost one of said pairs in said second zone of weft threads, carrying one of said warp thread ends, after having woven said warp thread end into said second zone of weft threads in accordance with the correct weaving pattern, in a loop around said possibly existing thin folding wire (or wires) as well as around said coarse folding wire and thereafter carrying^' said warp thread end in the reverse direction in the position

"SUREST OMPl

.Λ S.. 1FOO _,<\,j of said second warp thread to a pick-up point in said second zone of weft threads, at which point said two warp threads meet, where at least two of three consecutive warp thread ends according bo the pattern repeat- bind between the threads of the outermost pair of said second zone of weft threads, one of these warp thread ends after having been woven according to the pattern into said second zone of weft threads is carried in a loop about the possibly existing thin folding wire (or wires) as well as the coarse folding wire and then back in the place of one of the other warp threads to a pick-up point in the said second zone of weft threads, at which point the two warp threads meet each other whereas the third warp thread after having been woven according to the pattern into said second zone of weft threads is carried to a pick-up point in connection with the outermost pair of weft threads of said second zone of weft threads, where two subsequent warp thread ends in accordance with the pattern repeat bind over and below, alternatively below, the threads of the outermost one of said pairs in said second zone of weft threads, carrying one of said warp thread ends, after having woven said warp thread end into said second zone of weft threads in accordance with the correct weaving pattern, around said outermost pair of weft threads and the possibly existing thin folding wire or wires and thereafter carrying said warp thread end in the reverse direction in the position of said second warp thread to a pick-up point in said second zone of weft threads, at which point said two warp threads meet, where at least two of three succeeding warp thread ends according to the pattern repeat bind over and below, alternatively- below, the threads of the outermost pair of said second zone of weft threads, one of these weft thread

OMPI after having been. oven into said second zone of weft threads in correct pattern, binds about said outermost pair and possibly the thin folding thread (or threads) and then back in the place of one of the other warp threads to a pick-up point in said second zone of weft threads, at which point the two warp threads meet, whereas the third warp thread end after having been woven into said second zone of weft threads in correct pattern is carried to a pick-up point in connection with the outermost pair of weft threads, where one warp thread end in accordance with the pattern repeat binds between alternatively above or below, .the threads of the outermost one of said pairs in said second zone of weft threads without being followed by a warn thread end having the same alternative binding pattern, carrying said warp thread end, after having woven said warp thread end in accordance with the correct weaving pattern into said second zone of weft threads, around said outermos ^'pair of weft threads and possibly said thin folding wire or wires to a pick-up point adjacent to said outermost pair of weft threads, and treating said warp thread ends at both edges of said weave in the same manner and preferably simultaneously, said coarse folding wire being common to said warp thread ends of both fabric end edges.

All loops included in the loop rows that are intended to be joined together by a locking wire are formed when warp threads in accordance with the pattern repeat bind between the weft threads of the outermost pair preceding the seam loop itself. In this manner, the warp thread in connection with the seam loop is well protected against wear. Owing to this arrangement, also the seam loop itself will have less thickness than the rest of the fabric, which also spares the seam loop itself from wear_,. Because one or several threads, which may be thin, at need are inserted only in one layer (single layer) between the double-layer fabric and the coarse folding wire, the openness is decreased in this part of the seam, whereby heavy marking is reduced and there are less risks of web breaks. At the same time, these extra threads do not cause an enlargement of the loops as they are inserted in a single layer half-way between the weft threads of the two layers. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in closer detail in the following with reference to the accompanying diagrammatical drawings, wherein the invention is imagine applied in a double-layer forming fabric of a seven-shaft design wherein each warp thread in sequence binds above a pair of weft threads, between a second pair, beneath a thi pair, between a fourth pair and a fifth pair, above a six pair and between a seventh pair before the procedure is repeated.

In the drawing, Fig. 1 shows the pattern design of the intended fabric,

Figs. 2a, 2b, 2c, and 2d show four different stages of producing a seam loop.

Figs. 3 to 6 illustrate the method in connection wit all threads of the applied pattern of the fabric. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

In the pattern design illustrated in Fig. 1, the hori zontal rows 1 and 2 illustrate the weft threads of the weave and the vertical rows 3 the warp threads of the wea Cross yarns 1 form the upper layer of weft threads and cross yarns 2 the lower layer. Blackened squares indicate that the warp thread crosses the respective weft. thread on the upper face. Accordingly, warp thread 3a binds

- above the first pair of weft threads 1a and 2a

- betv/een the second pair of weft threads 1b and 2b - beneath the third pair of weft threads 1c and 2c

-BϋREA T

O PI - between the fourth pair of weft threads 1d and 2d

- between the fifth pair of weft threads 1e and 2e ^•

- above the sixth pair of weft threads 1f and 2f

- between the seventh pair of weft threads 1g and 2g, before the procedure in repeated.

Fig. 2a shows warp thread 3a, permanently freed of weft threads in a first zone 4 at the right-hand part of the Figure. In the adjacent second zone 5, the weft threads have been temporarily removed, and a corresponding number of threads have thereafter been inserted to serve as. the warp in a known sewing machine (not shown) which is similar to a loom. At the far left, wire section 6 is shown as positioned laterally of the very seam area. In the sewing machine is additionally applied a thin extra folding wire 7 as well as a coarser folding wire 8. In Fig. 2a, the shed of the first warp thread 3a is formed in such a manner that weft threads 11b, 11c, 12c, 11d, 11e, 11g and folding wires 7 and 8 form the upper shed whereas weft threads 11a, 12a, 12b, 12d, 11f, 12f, and 12g form the lower shed. After ^' introduction of warp thread 3a, the shed is closed in the manner indicated in Fig. 2b. In Fig. 2c, the following shed is shown, formed in a manner identical with the shed associated with warp thread 3b in accordance with Fig. 1. Warp thread 3a is folded about folding wires 7 and 8 and is reintroduced over a portion of zone 5 to a pick-up location between threads 11a and 11c. The warp thread 3b is inserted in the shed up to the same pick-up location. In Fig. 2d, the shed is again in closed position. Warp thread 3a has formed the seam loop about folding wires 7 and 8. In the left-hand section of Fig. 3, warp thread 3a is shown on the one hand in its regular position and on the other in its re-introduced position after having been folded in the position of warp thread 3b. Both warp threads 3a and 3b, arranged in succession,- weave between threads 11g and 12g of the outermost pair in zone 5. This binding appears also from the pattern repeat design illustrated in Fig. 1, according to which warp threads 3a and 3b weave below the upper weft thread 1g but above the lower v/eft thread 2g. Warp thread 3c weaves above weft threads 1g and 2g of the outermost pair of zone 5, as appears from the pattern repeat design of Fig. 1 , but is followed by a warp thread 3d which weaves between said pair of weft threads. For this reason, warp thread 3a cannot form a seam loop but, as shown in Fig. 4, it is carried around the thin folding wire 7 to a pick-up location between said folding wire and the outermost pair of weft threads 11g an 12g.

In accordance with the pattern repeat design of Fig. warp threads 3d and 3e both weave between weft threads 1g and 2g of the outermost pair in zone 5. One of these warp threads, e.g. warp thread 3d, is inserted, as illu¬ strated in Fig. 5, first in zone 5 and is thereafter carri in a loop around the thin folding wire 7 as well as the coarse folding wire 8 back into zone 5 in the position of the second warp thread 3e up to an appropriate pick-up location (not. shown), where the warp thread 3d meets warp thread 3e. The loop 9b thus formed like loop 9a formed by warp threads 3a, serve as seam loops for the final joining together of the fabric ends.

Warp threads 3f and 3g weave in accordance with the pattern repeat design of Fig. ^'1 respectively above and bel the weft threads 1g and 2g of the outermost pair in zone 5 One of these warp threads, e.g. warp thread 3f is, as illustrated in Fig. 6, woven first into zone 5 and is thereafter carried around the thin folding wire 7 back into zone 5 in the position of the second warp thread 3g up to an appropriate pick-up location (not shown), where warp thread 3f meets warp thread 3g. In this case no seam loop is formed around folding wire 8.

-βϋREA c

OMPI At the opposite fabric end (right-hand section of ^• Figs. 3 to 6), one proceeds in the same manner, as indicated above, the two seam loops 10a (Fig. 4) and 10b (Fig. 6) thus being formed. Before mountingthe fabric on a paper machine, the fabric is opened up by removal of folding wire 8, and after mounting, the seam loops 9 and 10 are again placed in interdigited position and one or ' several locking wires are passed through the loops.

In a seam produced in this manner the warp threads in connection with the seam loops as well as the same loops themselves are in positions wherein they are well protected against wear. The additional folding wires, which are. re¬ tained in position by the warp threads that do not form seam loops, may be adjusted to ensure the correct size of the seam loops, in addition to which the openness is reduced to avoid pronounced marking and risks that web breaks may occur.

The invention is applicable to most double-layer fabrics of various patterns and is especially suitable for fabrics having non-symmetric patterns wherein the warp thread weaves differently in the two weft yarn layers.

In the illustrated embodiment the weaving pattern according to Fig. 1 is formed so that the warp threads 3a, 3d and 3f after having been folded may be reinserted in the place of the v/arp thread 3b, 3e and 3g, respectively. When other weaving patterns are used, it may be better to form the loop by reinserting the warp thread after having been folded not in the place of adjacent warp thread but in the place of the succeeding warp thread if this gives a more correct weaving pattern.

Such an embodiment requires that at least a first and a third warp thread lying adjacent a second warp thread of the same alternative binding, i.e. at least two of three consecutive warp thread ends according to the weaving repeat bind between alternatively above or below the threads at the outermost pair of weft threads of zone 5. The warp thread lying between is thereby carried to a pick-up point in connection to the said outermost pair of weft threads.

Claims

1. A method of providing a row of loops at each end of a forming fabric, a filter cloth, or a similar fabric, said weave comprising two layers of weft threads with the threads positioned in pairs 5 substantially one on top of the other, warp threads interconnecting said weft layers, and a locking wire intended to interconnect said rows of loops to form an endless fabric web, the method comprisin removing permanently the weft threads in a first 10 zone closest to one end edge of said fabric, removing temporarily the weft threads in a second zone adjacent.said first zone, arranging said temporarily removed weft threads, alternatively a corresponding number of weft threads, ^5 together with one coarse folding wire and possibly also one or several thin folding wires as a warp in a sewing machine similar, to a loom, of a kind known per se, wherein said coarse wire temporarily replaces said locking wire intended finally to interconnect the two 20 fabric ends, where two warp thread ends in succession in accordance with the pattern repeat bind between the threads of the outermost one of said pairs in said second zone of weft threads, carrying one of said warp 25 thread ends, after having woven said warp thread end into said second zone of weft threads in accordance with the correct weaving pattern, in a loop around said possibly existing thin folding wire (or wires) as well as around said coarse folding wire and thereafter 30 carrying said warp thread end in the reverse direction in the position of said second warp thread to a pick-up point in said second zone of weft threads, at which point said two warp threads meet, where at least two of three consecutive warp thread^" ends according to the pattern repeatbind between the threads of the outermost pair of said second zone of weft threads, one of these warp thread ends after having been woven according to the pattern into said second zone of weft threads is carried in a loop. about the possibly existing thin folding wire (or wires) as well as the coarse folding wire and then back in the place of one of the other warp threads to a pick-up point in the said second zone of weft threads, at which point the two warp threads meet each other whereas the third warp thread after having been woven according to the pattern into - said second zone of weft threads is carried to a pick-up point in connection with the outermost pair of weft threads of said second zone of weft threads, where two subsequent warp thread ends in accordance with the pattern repeat bind over and below, alternatively below, the threads of the outermost one of said pairs in said second zone of weft threads, carrying one of said warp thread ends, after having woven said warp thread end into said second zone of weft threads in accordance with the correct weaving pattern, around said outermost pair of weft threads and the possibly existing thin folding wire or wires and thereafter carrying said warp thread end in the reverse direction in the position of said second warp thread to a pick-up point in said second zone of weft threads, at which place said two warp threads meet, where at least two of three succeeding warp thread ends according to the pattern repeat bind over and below, alternatively below, the threads of the outermost pair of said second zone of weft threads, one of these weft threads. after having been woven into said second zone of weft threads in correct pattern, binds about said outermost pair and possibly the thin folding thread (or threads) and then back in the place of one of the other warp threads to a pick-up point in said second zone of weft threads, at which point the two warp threads meet, whereas the third warp thread end after having been woven into said second zone of weft threads in correct pattern is carried to a pick-up point in connection with the outermost pair of weft threads, where one warp thread end in accordance with the pattern repeat binds between alternatively above or below, the threads of the outermost one of said pairs in said second zone of weft threads without being followed by a warp thread end having the same alternative binding pattern, carrying said warp thread end, after having woven said warp thread end in accordance with the correct weaving pattern into said second zone of weft threads, around said outermost pair of weft threads and possibly said thin folding wire or wires to a pick-up point adjacent to said outermost pair of weft threads, and treating said warp thread ends at both edges of said weave in the same manner and preferably simultaneously, said coarse folding wire being common to said warp thread ends of both fabric end edges.

2. The method as claimed in claim 1, comprising forming said row of loops intended to be interconnected, in a forming fabric, a filter cloth or a similar fabric- having a non-symmetrical weaving pattern, wherein every one of said warp threads crosses one of the weft threads of said layers of weft threads a larger number of times than it crosses the weft threads of the other one of said layers. AMENDED CLAIMS

(received by the International Bureau on 17 November 1978 (17.11.78)

1. A method of providing a row of loops at each end of a forming fabric, a filter cloth or a similar fabric, said fabric comprising tu/o layers of weft threads u/ith the threads positioned in pairs substantially 5 one on top of the other and uarp threads interconnecting said weft layers where the u/eft threads are permanently removed in a first zone closest to one end edge of said fabric and temporarily removed in a second zone adjacent to said first zone, where a number of weft threads

10 corresponding to the temporarily removed weft threads together with a at least one folding thread are drawn in as a warp in a joining machine similar to a loom, and where one of said folding threads is coarse and temporarily replaces the cable intended finally to

15 interconnect the two fabric ends, the method comprising the proceeding, where two warp thread ends in succession in accordance with the weave pattern bind between the threads of the ouerrmost one of said pairs in said

20 second zone of weft threads, carrying one of said warp thread ends, after having woven said warp thread end into said second zone of weft threads in accordance with the correct weaving pattern, in a loop around all of the folding threads and thereafter carrying said warp

_^.5 thread end in the reverse direction in the position of said second warp thread to a pick-up point in said second zone of weft threads, at which point said two warp threads meet, where at least two of three consecutive warp thread .O ends according to the weave pattern bind between the

IjftR^EAlT

OtøPI

, A ^ry_ W WiiPFOU threads of the outermost pair of said second zone of weft threads, one of these warp thread ends after having been woven according to the pattern into said second zone of weft threads is carried in a loop around all of the folding threads and then back in the place of one of the other warp threads to a pick-up point in the said second zone of weft threads, at which point the two warp threads meet each other whereas the third warp thread after having been woven according to the pattern into said second zone of weft threads is carried to a pick-up point in connection with the outermost pair of weft threads of said second zone of weft threads, where two subsequent warp thread ends in accordance with the weave pattern bind outside the threads of the outermost one of said pairs in said second zone of weft threads, carrying one of said warp thread ends, after having woven said warp thread &nd into said second zone of weft threads in accordance with the correct weaving ^•pattern, around said outermost pair of weft threads and also around the folding threads beyond the coarse folding thread and thereafter carrying said warp thread end in the reverse direction in the position of said second warp thread to a pick-up point in said second zone of weft threads, at which place said two warp threads meet, where at least two of three succeeding warp thread ends according to the weave pattern bind outside, the threads of the outermost pair of said second zone of weft threads, one of these warp thread ends after having been woven into said second zone of weft threads in the correct pattern, is carried around said outermost pair of weft threads and also around the folding threads beyond the coarse folding t____read and then back in the place of one of the other warp threads to a pick-up point in said second zone of weft threads, at which point the two warp threads meet, whereas the third warp thread end after having been woven into said second zone of weft threads in correct pattern is carried to a pick-up point in connection with the outermost pair of weft threads, where one first warp thread end in accordance with the weave pattern binds between the threads of the outermost one of said pairs in said second zone of weft threads and is followed by a second warp thread end binding outside the threads of said outermost pair of weft threads said first warp thread end is carried, after having woven in accordance with the correct weaving pattern into said second zone of weft threads, around said outermost pair of weft threads and also around the folding threads beyond the coarse folding thread to a pick-up point adjacent to said outermost pair of weft threads, where one first warp thread end in accordance with the weave pattern binds outside the threads of the outer¬ most one of said pairs in said second zone of weft threads and followed by a second warp thread end binding between the threads of said outermost pair of weft threads, said first warp thread end is carried, after having been woven in accordance with the correct weaving pattern into said outermost pair of weft threads and also around the folding threads beyond the coarse folding thread to a pick-up point adjacent to said outermost pair of weft threads, J-⁷ where the warp thread ends at both edges of the fabric are treated in the same manner and preferably simultaneously, where said coarse folding thread is common to said warp thread ends of both edges of the fabric.

2. The method as claimed in claim 1, comprising forming said two of loops intended to be interconnected, in a forming fabric, a filter cloth or a similar fabric having a non-symmetrical weaving pattern, wherein every one of said warp threads crosses one of the weft threads of said layers of weft threads a larger number of times than it .crosses the weft threads of the other one of - said layers.

STATEMENTUNDERARTICLE19

The Search Report has found the following two documents to be relevant, viz. SE 310 869 and SE 322 980.

On page 2 of the subject application, Applicants refer to SE 322 980 as one example of a prior-art seam wherein the weft threads are removed to give free warp ends, whereafter the warp threads are woven back into the fabric. SE 322 980 additionally describes a method of providing a seam of this kind in a single-layer structur by weaving every other warp thread back into the weave after having been formed into a locking loop.

The preamble of SE 310 869 describes briefly an identical method of bending the warp threads and thereafter weaving them back into the weave. However, this publication is mainly concerned with a device to produce a seam. The joining machine, similar to a loom, referred to in the main claim as well as on pages 3 and 7 of the description of the subject application is precisely

the kind of joining machine that Applicants have in mind, and for this reason the introduction of the description of the subject application should be amended to include a reference to SE 310 869.

The two cited Swedish publications are referred to category "A" and thus mainly indicate the general state of the art. However, some features appearing in the original main claim of the subject application are known from the cited publications, viz. the weft threads in a first zone closest to one end edge of the fabric being permanently removed the weft threads in an adjacent second ^"zone being temporarily removed arranging the weft threads and the folding wires in a joining machine.

In view hereof and pursuant to Article 19 and Rule 46.5 Applicants therefore herewith submit amended claims, replacement sheets 11, 12, 13 and 14, to replace sheets 11, 12 and 13 originally filed.

The new main claim differs from the replaced one in that the above features are recognized therein as prior art and therefore now appear in the preamble. In addition thereto, the claim is amended to recite the inven¬ tion positively, avoiding alternatives, and also so as to set forth the invention more .clearly. The last clause of the original main claim, corresponding to the last four..lines thereof, is replaced by an entirely reworded passage, appearing on the last eleven lines of replacement sheet 13 and lines 1 - 5 of replacement sheet 14.

The enclosed claim 2 is identical with claim 2 on file. A new abstract revised in conformity with the amended main claim is likewise enclosed herewith.