Note: Descriptions are shown in the official language in which they were submitted.
~5~7~5
--1--
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to seaming means, a method and
apparatus ~or forming the seam, and more particularly to a
self-locking seam which can bë used to join the two ends of
a piece of fabric to create an endless belt.
.
2. Description of the Prior Art
Fndless belts made out of woven fabric materials are
used in a num~er of fields. Their use is especiall~
prominent in the papermaking indus.ry where such belts are
used in the forming, pressing and drying of continuous
sheets of paper. In order to insure that the belts in this
industry have a long useful li~è the seams must be strong.
On the other hand, the seams cannot exhibit substantial
surface variations, or they will mark the paper.
One type of seam which has proven to be fairly reliable
in the paper industry is the so-called pintle seam, such as
the one described in the commonly assigned U.S. Patent No.
4,123,022. These seams comprise intermeshing juxtaposed
loops formed on each end of the fabric. There are several
methods which may be used to secure the loops to the belt
fabric. For example, the loops may be sewn on a webbing
and then the webbing may be secured to the belt fabric.
7~
Another method is to fold over the ends of the fabric and to
insert a spiral coil formed of interconnected loops between
the fabric threads. A third method comprises reweaving the
machine direction yarns back into the fabric after they are
shaped into loops. All these seam loops have a distinct
disadvantage in that they are very time consuming to mesh
together. For example, after the loops have been secured to
the fabric ends by using one of the methods outlined above,
depending on the width and fineness of the fabric, it takes
between one-half and eight hours to join the ends to for~
the belt. Furthermore, at least two persons are needed to
mesh loops and push the pin through the loops respectively,
and several other persons are required to hold down the rest
of the fabric. This is also compounded if the meshing
location is not in a convenient place, i.e. working upside
down.
OBJECTIVES AND SUMMARY OF THE INVENTION
In view of the above-described disadvantages of
prior art seams, the objective of the present invention i~s
to provide a seam which can be used to join the ends of a
fabric in a short period of time.
A further objective is to provide a seam with which two
ends of a wide fabric may be joined by one or two persons.
A further objective is to provide a device for joinin;
the seam loops fast and efficiently. Other objectives and
advantages are described in the description of the preferred
embodiment.
- .. .....
7~i
-- 3
The above objectives are realized by a seam com-
prising two coils which are affixed respectively to the ends
of a fabric, at least one of the coils being preformed to
interlock with the other so that after the coils are inter-
meshed there is an interference fit- therebetween. The
interlocked loops define a tubular orifice across the width
of the fabric through which a pintle can be introduced to
reinforce the seam and create a positive lock.
Since the loops of one end actually grip the
respective loops of the other end rather than being merely
intermeshedr a force is required to overcome the elasticity
of the loops and bring the loops together. This force is
generated by a device which first superimposes the two ends
of the fabric so that the ends are displaced along a plane
which is substantially perpendicular to the fabric ends and
then forces the coils together as the device slides along
the ends to form the seam.
The tool comprises two plates which, when ~&~e~,
form a first channel joined to a second channel, wi~h the
first and second channels being displaced along a plane
which is substantially perpendicular to the fabric. The
loops are intermeshed as each of the coils is passed through
one of the channels as the tool is passed along the ends.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a side view of the fabric ends and
the seam coils.
Figure 2 is an end view of the seam coils of
Figure 1.
Figure 3 is a top view of the seam coils of
Figure 1.
~Z~7'~9
- 3a -
Figure 4 is a plan view of the completed seam.
Figure 5 is a side view of the seam of Figure 4.
Figure 6 is a side view of the tool used to com-
plete the seam.
Figure 7 is a partial top view of the tool of
Figure 6.
~;~54725
--4--
Figure 8 is a partial bottom view the top pressure plate;
and
Figure 9 shows a seam being completed by the tool of Figure
6.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Joining edges of fabrics by devices known as zippers is
well known, especially in the garment industry. These
zippers traditionally comprise two tapes, each fastened to a
fabric end at one edge, with a series of plastic or metal
teeth disposed along the opposite edges of the tape, said
teeth being interconnected to each other when they are
intermeshed by a slide by an interferance fit between the
teeth of one tape and the corresponding opposite teeth of
the other. The teeth are clamped or otherwise permanently
fastened to the tapes.
A recent development in these devices has been the use
of a continuous series of interconnected loops for each tape
instead of the individual teeth, which are sewn on to said
opposite edges of the tapes. The inventor has found that
these continuous loops, which from hereon shall be called
coils, can also be used to form a seam for continuous fabric
belts even if the fabrics are very stiff and are woven out
of relatively thick, rigid plastic threads, such as the one
normally used for forming fabrics and dryer fabrics.
A typical dryer fabric of the type described above is
shown in Figure 1. It comprises two rows of weft yarns 10,
20 between which the warp yarns 30, 40 are woven in the
~%s~
5 --
usual manner. After the last row of weft yarns each warp
yarn is folded back into a loop 50 after which it is woven
back into the fabric by using a hand weaving device. This
process is more fully disclosed in U. S. Patent 4,401,137,
issued on August 30, 1983. The threads are.preferably
fairly rigid plas-tic monofilaments to impart the fabric the
required stiffness.
A continuous coil 80 is attached to the fabric end
70 formed by loops 50, preferably by threading it through
loops 70 before the warp yarns are rewoven into the fabric
as described above. The coil is fo.rmed of a plurali-ty of
loops 80, each loop being interconnected to the adjacent
loops. Each loop is in the shape of a reiatively flat
. ellipse. The plane of all the loops of a coil are substan-
tially in parallel, lie perpendicularly to the plane of the
fabric and extend away from the respective fabric end.
The coil is preferably a nylon or polyester mono-
filament. The end of each loop 80 opposing the fabric end
is distorted to form a head 90 which has width T' in the
perpendicular direction to the ellipse plane which is larger
than the normal thickness T of the monofilament. As can be
seen in Figures 2 and 3, each successive loop is spaced at a
distance D from the previous loops. However, because the
heads 90 are thicker than the rest of the loops so that the
distance D' between the heads is smaller -than the thickness
T.
The other end 100 of the fabric is finished in the
identical manner to end 70 with a co;.l 1l0 which is
7~2S
identical to coil 60n The loops 112 of coil 110 are in
parallel to the loops 80 of coil 60.
Coils 60 and 110 respectively are further secured to
ends 70 and 100 by retaining pins 85 and 115 which are
introduced alte.rnatively between the fabric ends and the
coil loops.
The seam is completed by joining the two ends 70 and
100 together, thereby forcing the loops 80 and 100 to
intermesh. This action forces the head of each loop of one
end to be inserted in between and engage two corresponding
. loops of the other end, as shown in Figures 4 and 5 to form
an interference fit thexebetween. For best results the
distance D between adjacent loops of a coil is substantially
the same as the filament thickness T 50 that, when the
respective loops are intermeshed, each loop is in physical
contact with the loops of the opposite coil. The head of
the loop is actually.disposed inside the adjacent loops, as
shown in Figure 4. For clarity, the loops in Figure 4 are
shown slightly spread apart so that D is larger than T. A
dxyer fabric was joined in this manner and it was found that
the seam had a tensile strength in excess of 200 pounds per
linear inch.
Importantly, the respective loops from tile opposing
coils overlap enough in the closed position shown in Figùres
4 and 5 so that inner face 120 of coil 80 and inner face 130
of coil 11~ both of which are substantially semi-cylindrical
as viewed from the side complement each other, and define a
substantially cylindrical tube through the seam across the
7~5
width of the fabric. A pin 140 is passed through the tube
to secure the coils to each other, and thereby strengthen
the seam. The pin may be a rigid metal pin or a plastic
monofilament. It has been found that the tensile strength
of the dryer fabric is dramatically increased by the pin
from 200 to over 500 lbs per linear inch.
The force necessary to intermesh the individual loops
is relatively small so that the above-described seam may be
closed manually, preferably by starting on one side and
pushing carefully the two ends together. However this
process is rather tedious and for belts in excess of 3-4
~eet in width, more than one person is needed to complete
it. Therefore a tool has been devised for closing the seam
in an expeditious manner.
The tool 190 illustrated in Figures 6-8 comprises a top
and a bottom pressure plate 200, 210, which are brought into
an opposing relationship as shown in Figure 6 by the two
scissored arms 220 and 230 respectively. Plate 200 is
joined to arm 220 by a vertical stud 240 while plate 210 is
joined to arm 230 by screw means 250. The arms are
rotatably joined by pivoting screw 260. Each arm has a
handle hole 270 and 280 provided to enable to hold and
operate the tool just like a regular scissor. Separating
the handle ends also separates the plates and vice versa.
The top plate 200 is illustrated in more details in
Figure 8. The bottom surface of the plate comprises a first
substantially flat area 290, a second substantially flat
~S~72~i
- --8--
area 300 which is essentially coplanar with the first area
290 and a third substantially ~lat area 310.
When the tool is used to close a seam, it is moved in
the direction shown by arrow 400 so that while the first and
third areas are adjacent to each other the second area is
"downstream" with respect to both of them. The first and
third areas are joined by a substantially vertical wall 330
which, as shall be seen later, defines the p}ane in which
the coils are joine~. As shown in Figure 8, the third area
310 is offset vertically from the first and second areas 290
and 300 and furthermore it is positioned above said area.
The vertical distance therebetween is about half an inch. A
slanted area 340 joins the second area 300 to the third area
310. Holes 350, 3~0, and 370 are provided in each o~ the
plates to hold pressure rollers. The function of these
rollers shall be described below.
The bottom plate 210 has a top surface which is
complementary to the bottom surface of the top plate so that
the two plates may be brought into a mating relationship as
shown in Figure 6.
The above mentioned pre~sure rollers are illustrated in
Figure 7. One pressure roller 375 is installed in hole 370
so that its axis of rotation is transversal to the direction
of movement of the tool 190 indicated by the arrow. Rollers
355 and 365 are installed respectively symmetrically in
holes 350 and 360. Their axis of rotation X-X and Y-Y form
an angle A with said direction of movement which, as shown
in Flgure 7, is less than 90~. For exa~ple, angle A may be
7Z~i
60~. The bottom plate is provided with similar rollers
disposed beneath the top rollers so that when a fabric i~
introduced therebetween, pressure nips are formed between
the respective rollers.
The tool operates as follows. As the two plates are
positioned close to each other two channels are formed
therebetween. The lower channel is essentially horizontal
and is defined by the first area 290, second area 300 and
corresponding areas of the bottom plate. The higher channel
starts off in paxallel with the lower channel and is defined
by third area 310, vertical wall 330 and the corresponding
areas of the lower plate. The upper channel then angles
~oward and joins the lower channel as it follows inclined
surface 340. Thus the two channels form a Y.
In order to use the tool, corners 75 and 105 of
respective fabric ends 70 and 100 are inserted between the
plates 200, 210 of tool l90, the handles are gripped to
apply pressure to the fabric and the tool is moved in the
direction of the arrow 400 of Figure 9. As shown in ~igure
- 20 6, end 100 passes through the higher channel while end 70
passes through the lower channel~ As the ends pass through
the tool, they are rorced toward a common vertical plane
defined by wall 330. In this manner the tool insures that
just before the coils 80 and 110 are enmeshed they are
juxtaposed along a substantially vertical plane, parallel
with vertical wall 330. The act~lal meshing of the coils
takes place as the loops of coil llO of the upper end lO0
are pushed into the loops of coil 80 of the lower end 100 as
~25~
--10--
the upper end is traveling along the inclined surface 340.
This action is aided by roller 375 which presses against the
loops. By the time ~he two ends reach the second area 300,
the coils are joined so that the ends are coplanar and have
been seamed as shown in Figures 4 and 5.
A substan~ially horizontal guide 390 is attached to
the upper plate to guide end 100 between the two plates.
The overall width of the tool is in the range o~ 3-5
inches, so that it is not too big to be manipulated with one
hand. As the arms of the tool are squeezed together the
plates are ~orced against the fabric ends and the rollers.
Preferably the distance from the handle holes 270 and 280 to
the piVQt 260 is larger than the distance from the pivot
point to the plates so that a mechanical advantage can be
generated.
The inventor has found that by using the
above-mentioned tool and seam means even a twenty foot wide
belt may be formed by joining the respective fabric ends in
less than a minute. Since the coils are joined by the
interference fit and in effect are self-locking, only two
people are needed to join the fabric end, one to hold the
fabric ends while the other one forces the coils to
intermesh. Once the coils are interlocked a slight tension
is applied to them to keep them straight. In this position
the heads of the loops interlock to create the tube as shown
in Figure S, allowing the pintle 140 to be inserted
therebetween. A single person is able to push the pintle
across the whole width ~f the fabric,
~547Z~
One major feature of the tool is that, as described
above, it overlaps the two ends while keeping them offset so
that they are not coplanar. This feature is important
especially when fabric is a stiff forming fabric. Normally
such fabrics exhibit two dimensional stability. In other
words, they resist forces that are co-planar with the
fabric. If a force which is coplanar with the fabric is
applied t~ the fabric edge, ~he fabric will resist the force
and it will contort in a direction normal to its planeO
Normally the edges of two fabrics are zipped by placing the
edges side by side in essentially the same plane as the two
fabrics. Thus, while the edges are being joined, the seam
and the remaininy portions of the edges form a ~ in the
plane of the fabrics. However dryèr fabrics could not be
zippered in this manner for the reasons outlined above. The
tool presented herein above solves this problem by zippering
two fabrics such that, the seam and the two edge portions
form a Y (as shown in Figure 6) which is normal to the
planes of the fabrics.
Numerous modifications may be made to the invention
without departing from its scope as defined in the appended
claims.
This application is a division of application
Serial No. 451r 900~ filed April 12, 1984.
