CA1262669A

CA1262669A - Pin seamed fabric

Info

Publication number: CA1262669A
Application number: CA000495283A
Authority: CA
Inventors: Frank Clarence Nowak; Thomas George Gulya
Original assignee: Appleton Mills
Current assignee: Appleton Mills
Priority date: 1984-11-19
Filing date: 1985-11-14
Publication date: 1989-11-07
Also published as: FI81850B; EP0182597A1; FI854472A; DE3569763D1; AU4987385A; EP0182597B1; FI854472A0; ATE42584T1; AU566997B2

Abstract

PIN SEAMED FABRIC
Abstract of the Disclosure A method of producing an endless pin seamed fabric having particular use as a fabric on a paper-making machine. The fabric is a woven warp and weft system formed by weaving a single continuous warp yarn with an array of parallel weft yarns in a series of forward and reverse picks. During the weaving opera-tion, the warp yarn is selectively looped around a pin disposed parallel to an end yarn in the array of weft yarns in a series of loops to form an endless pin seamed fabric. After weaving, by removal of the pin, the endless fabric can be opened and readily installed on a papermaking machine. The region of the fabric adjacent the pin seam has a uniform porosity and a constant thickness.

Description

PIN SEAMED FABRIC
Background of the Invention In the past fabrics for papermakiny machines, such as forming fabrics, dryer fabrics and felts, have been supplied as open-ended flat fabrics, and a~ter installation on ~he papermaking machine the ends of the fabric were joined or rewoven into endless form. Re-weaving is an extremely tedious manual operation which results in substantial down time for the papermaking machineO
To o~ercome the need for reweaving the fabric on the papermaking machine, pin seamed fabrics have been utilized. With the pin seamed fabric, loops are attached to the ends of the fabric and a pin is insert-ed through the interdigitated loops to provide a con-nection. The pin seamed fabric has the advantage that it can be opened and installed on the papermaking machine and the pin then inserted through the inter-digitated loops to provide the endless configuration.
In one common form of pin seamed fabric, metal loops are connected by clips to the end of the fabric. ~ue to the thickness of the metal clips, it is nPcessary to add weft yarns adjacent the clips in order to taper the thickness from the metal clips to the body of the fabric~ Increasing the number of weft yarns in the region of the pin seam decreases the permeability in this region and also increases the thickness. The increased thickness makes the fabric unsuitable for use as a papermaker's felt due to the fact that the felt, in operation, is passed through a nip between pressure rolls to extract water from the paper web.
In the past, the pin seamed fabrics have also been formed through use of spiral plastic members which were woven into the ends of the fabric. As in the case of the metal loops, the plastic spiral loops produce an s3 --2~

increase in thickness in the seam area and a decrease in permeability.
In an attempt to provide more uniformity in porosity and thickness in the pin seamed area, woven back structures have been utilized. In a woven back structure, the weft yarns in the end of the fabric are removed and the projecting warp yarns are then folded back to form loops and interwoven with the fabric.
Vnited States Patents Nos. 2,325,900, 3,436,041, 4,026,330, ~,095,622, 4,182,381 and 4,401,137 show various types of woven back fabrics.
However, in the woven back fabric, problems have been encountered in retaining the integrity of the loops formed by the woven back warp yarns because the woven back yarns tend to slip or loosen~ Furthermore, severing the warped yarns in the woven back structure seriously impairs the strength of the fabric, as oppos-ed to a fabric using continuous non-broken yarns.
As a further disadvantage, additional weft yarns are required in the area of the pin seam in order to adequately hold the woven back warp yarns in posi-tion, so that the loops do not elongate. The addition of the added weft yarns decreases the porosity of the fabric in the area of the pin seam, as well as provid-ing an increase in ~hickness.
Papermaking fabrics have also been woven in endless form without a seam and an endless fabric has the inherent advantage of uniform porosity and thick-ness throughout its length. Endless fabrics, however, present certain problems in installation on the paper-making machine. To install the endless fabric, it is necesssary to shift the roll mountings and slip the fabric over the rolls. Recently, due to the advent of stiffer, bulkier fabrics the problem of installation of an endless felt has been accentuated. The installation w2 ~

~2~ 4~S3 of an endless fabric on a papermaking machine is a time-consuming operation which requires substantial down time for the machine.
Summary_of the Invention The invention is directed to a method of producing an endless pin seamed fabric having par-ticular use as a forming fabric, a dryer fabric, or a felt on a papermaking machine.
In accordance with the inventionl the fabric is a woven warp and weft system formed by interweaving a single warp yarn with an array of parallel weft yarns in a series of forward and reverse picks. During the weaving operation, the warp yarn is selectively looped around a pin disposed parallel to an end yarn in the array of weft yarns to form a series of loops around the pin.
After the weaving operation has been com-pleted, the pin can be removed so that the fabric can be opened up and readily installed on the papermaking machine. After installation, the pin can be reinserted through the interdigitated loops on the ends of the fabric.
The fabric of the invention has a uniform porosity in the area of the pin seam and a constant thickness. Thus, the fabric has the inherent advan-tages of an endless fabric, and due to the pin seam, can be readily opened up and installed on the paper-making machine.
As a further advantage, the fabric includes a single continuous warp yarn which is unbroken and this not only increases the strength of the fabric, but also prevents the loops from elongating in service, as can occur with the woven back type of loop construction.
While the fabric of the invention can be used as a forming fabric, or dryer fabric, it has particular use as a papermaker's felt due to the fact that the thickness in the area of the pin seam is not increased and the porosity in this area is uniform.
Other objects and advantages will appear in the course of the following description.
Description of the Drawings The drawings illustrate the best mode presently contemplated of carrying out the invention.
In the drawings:
Fig. 1 is a plan view of the pin seam area of the fabric of the invention;
Fig. 2 is a section taken along line 2-2 of Fig. l; and FigsO 3A-3H are schematic representations illustrating showing the picks of the warp yarn in the weaving operation.
Description of the Illustrated Embodiment Fig. 1 shows a pin seamed fabric 1 that has particular use as a fabric for a papermaking machine.
More particularly, the fabric can be used as a paper-maker's felt or as a forming fabric or dryer fabric.
Fabric 1 includes an array or plurality of parallel weft yarns 2, and a single, continuous warp yarn 3 is interwoven with the weft yarns. Certain picks or passes of the warp yarn 3 form projecting loops 4 and a pin 5, formed of plastic or metal, is inserted through the aligned interdigitated loops 4 to connect the ends of the fabric together.
As set forth in the specification and claims, the term "warp yarn" is used as in papermaker's termin-ology in which the warp yarns extend longitudinally of the fabric or in the machine direction.
The term "yarn" as used in the specification and cIaims is intended to include stands of monofila-ment, multifilament, fiber materials, or mixtures of these materials in either twisted, untwisted, inter-twined, or plied form.
The yarns can be formed o~ any desired mater-ials, such as wool or synthetic materials, but it is preferred that the warp yarn 3 be formed of a material which will tend to retain the integrity o the loops 4 when the pin 5 is removed.
Figs. 3A-3H illustrate the endless weaving pattern for forming a two-layer fabric. While Figs~
3A-3~ for purposes of illustration, merely show five vertical rows of weft yarns 2, in practice there may be hundreds or thousands of rows of weft yarns depending upon the length of the endless fabric to be produced.
As shown in Fig. 3A, the pin 5 is positioned parallel to an end yarn in the array of weft yarns 2, and in the first pick, the warp yarn 3 is interwoven with the weft yarns of ~he upper layerO Fig. 3A shows the warp yarn 3 going over and under adjacent weft yarns 2, but it is contemplated that any desired weav-ing pattern can be employed.
While Fig. 3A-3H shows the warp yarn 3 moving in a sinusoidal path, in practice the weft yarns 2 would be raised and lowered by harnesses to the desired position, and the warp yarn would be moved horizontally by a shuttle in a straight path to provide the inter-weaving.
As shown in Fig. 3B, warp yarn 3 is looped around pin 5 to form a loop 4 and is then interwoven in the upper layer of weft yarns 2 in a return or second pick.
Following this, the warp yarn 3 is interwoven in a third forward pick with the weft yarns of the lower layer (Fig. 3C), and the warp yarn is then looped around the end weft yarns in the lower layer and inter-woven with the weft yarns of the lower layer in a return pick, as shown in Fig. 3D.

Following the return pick, the warp yarn 3 is again interwoven wi~h the wefc yarns 2 of the upper layer, as illustrated in Fig. 3E and is then interwoven in a return pick as illustrated in Fig. 3F.
Warp yarn 3 then is interwoven with the weft yarns of the lower layer in a forward pick (Fig~ 3G) and is looped around the pin 6 to form a second loop 4 and interwoven with the weft yarns in the lower layer in a return pick, as illustrated in Fig. 3H. This pattern is repeated throughout the width of the fabric.
While Figs. 3A-3H show the weft yarns 2 arranged in four vertical rows (indicted by 2a-2d in Fig. 3A) to form a double layer fabric, it is contem-plated that the weft yarns can also be arranged in only two rows in which case a single layer fabric can be produced.
The resulting woven structure is an endless fabric in which certain picks or passes of the single continuous warp yarn 2 are looped around the pin 5. By removal of pin S, the fabric can be opened up and con-veniently installed on the papermaking machine. After installation, the pin can be reinserted within the aligned interdigitated loops 5.
The woven fabric of the invention has par-ticular use as a base fabric for a papermaker's felt.
In this situation, one or more layers of fibrous batt can be needled into one or both surfaces of the base fabric. The needling operation may tend to damage the pin 5, so that after needling, the damaged pin can be removed and when the felt i5 installed on the paper-making machine, a new pin can be replaced.
The fabric of the invention has a constant thickness and permeability adjacent the pin seam. As the warp ~arn is continuous, the fabric has improved strength over woven back types of fabric in which the warp yarns are severed.

The fabric can be readily woven on a standard weaving loom and no special equipment is required.
Furthermore, the loop construction is made during the regular weaving process, so that ~he pin seamed fabric can be produced in a substantially shorter period of time than other pin seamed fabrics utilizing metal clips, plastic spirals, or woven back warp yarns.

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Claims

THE EMBODIMENTS OF THE INVENTION TO WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An endless pin seamed fabric, comprising a woven fabric, including a plurality of generally weft elements and a single continuous warp element inter-woven with said weft elements, said weft elements including a pin and adjacent yarns on either side of said pin, said warp element being interwoven with said weft elements in a plurality of picks, every other pick being looped around the pin in a plurality of first loops and alternate picks being looped around said adjacent yarns in a plurality of second loops offset from said first loops, said pin being removable from said first loops to enable the fabric to be open to a generally flat condition.

2. The fabric of claim 1, and including a layer of fibrous batt needled to at least one surface of said fabric.

3. A method of producing an endless pin seamed fabric, comprising the steps of arranging a group of weft yarns in a parallel pattern, disposing a pin parallel to said group of weft yarns, interweaving a single continuous warp yarn with said weft yarns in a series of picks and looping the warp yarns around the pin in every other pick and looping the warp yarn around a weft yarn adjacent to said pin in every alternate pick.