There are a few distinct methods of preparing warp threads on the
weaver's beam. Stated briefly, the chief methods are--
1. The warp is made in the form of a chain on a warping mill, and
when the completed chain is removed from the mill it is transferred
on to the weaver's beam.
2. The warp is made in the form of a chain on a linking machine, and
then beamed on to a weaver's beam.
3. The warp yarns are wound or beamed direct from the large
cylindrical "rolls" or "spools" on to a weaver's beam.
4. The warp yarns are starched, dried and beamed simultaneously on
to a weaver's beam.
The last method is the most extensively adapted; but we shall
describe the four processes briefly, and in the order mentioned.
For mill warping, as in No. 1 method, from 50 to 72 full spinning
bobbins are placed in the bank or creel as illustrated to the right
of each large circular warping mill in Fig. 27. The ends of the
threads from these bobbins are drawn through the eyes of two leaves
of the "heck," and all the ends tied together. The heck, or
apparatus for forming what is known as the weaver's lease, drawer's
lease, or thread-by-thread lease, is shown clearly between the
bobbin bank and the female warper in the foreground of the
illustration. The heck is suspended by means of cords, or chains,
and so ranged that when the warping mill is rotated in one direction
the heck is lowered gradually between suitable slides, while when
the mill is rotated in the opposite direction the heck is raised
gradually between the same slides. These movements are necessary in
order that the threads from the bobbins may be arranged spirally
round the mill and as illustrated clearly on all the mills in the
figure. The particular method of arranging the ropes, or the gearing
if chains are used, determines the distance between each pair of
spirals; a common distance is about 1-1/2 in. There are about
42 spirals or rounds on the nearest mill in Fig. 27, and this number
multiplied by the circumference of the mill represents the length of
the warp.
[Illustration: FIG. 27 A ROW OF MODERN WARPING MILLS]
At the commencement, the heck is at the top, and when the weaver's
lease has been formed on the three pins near the top of the mill
with the 50 to 72 threads (often 56), the mill is rotated by means
of the handle and its connections shown near the bottom of the mill.
As the mill rotates, the heck with the threads descends gradually
and thus the group of threads is disposed spirally on the vertical
spokes of the mill until the desired length of the warp is reached.
A beamer's lease or "pin lease" is now made on the two lower pegs;
there may be two, three, four or more threads in each group of the
pin lease; a common number is 7 to 9. When this pin lease has been
formed, one section of the warp has been made, the proportion
finished being (50 to 72)/x where x is the total number of threads
required for the cloth. The same kind of lease must again be made on
the same two pins at the bottom for the beginning of the next
section of 50 to 72 threads, and the mill rotated in the opposite
direction in order to draw up the heck, and to cause the second
group of 50 to 72 threads to be arranged spirally and in close touch
with the threads of the first group. When the heck reaches the top of
the mill, the single-thread lease is again made, all the threads
passed round the end pin, and then all is ready for repeating the
same two operations until the requisite number of threads has been
introduced on to the mill. If it is impossible to accommodate all the
threads for the cloth on the mill, the warp is made in two or more
parts or chains. It will be noticed that the heck for the nearest
mill is opposite about the 12th round of threads from the bobbin,
whereas the heck for the second mill is about the same distance from
the top. A completed warp or chain is being bundled up opposite the
third mill. When the warp is completed it is pulled off the mill and
simultaneously linked into a chain.
A very similar kind of warp can be made more quickly, and often
better, on what is termed the linking machine mentioned in No. 2
method. Such a machine is illustrated in Fig. 28, and the full
equipment demands the following four distinct kinds of apparatus--a
bank capable of holding approximately 300 spools, a frame for
forming the weaver's lease and the beamer's lease, machine for
drawing the threads from the spools in the bank and for measuring
the length and marking the warp at predetermined intervals, and
finally the actual machine which links the group of threads in the
form of a chain.
In Fig. 28 part of the large bank, with a few rows of spools, is
shown in the extreme background. The two sets of threads, from the
two wings of the bank, are seen distinctly, and the machine or frame
immediately in front of the bank is where the two kinds of lease are
made when desired, i.e. at the beginning and at the end of the warp.
Between this leasing frame and the linking machine proper, shown in
the foreground, is the drawing, measuring and marking machine. Only
part of this machine is seen--the driving pulleys and part of the
frame adjoining them. All these frames and machines are necessary,
but the movements embodied in them, or the functions which they
perform, are really subsidiary to those of the linker shown in the
foreground of Fig. 28.
[Illustration: FIG. 28 POWER CHAIN OF WARP LINKING MACHINE]
Although the linking machine is composed of only a few parts, it is
a highly-ingenious combination of mechanical parts; these parts
convert the straight running group of 300 threads into a linked chain,
and the latter is shown distinctly descending from the chute on to
the floor in the figure. Precisely the same kind of link is made by
the hand wrappers when the warps indicated in Fig. 27 are being
withdrawn from the mills. Two completed chains are shown tied up in
Fig. 28, and a stock of rolls or spools appear against the wall near
the bank.
The completed chain from the warping mill or the linking machine is
now taken to the beaming frame, and after the threads, or rather the
small groups of threads, in the pin lease have been disposed in a
kind of coarse comb or reed, termed an veneer or radial, and
arranged to occupy the desired width in the veneer, they are
attached in some suitable way to the weaver's beam. The chain is
held taut, and weights applied to the presser on the beam while the
latter is rotated. In this way a solid compact beam of yarn is
obtained. The end of the warp--that one that goes on to the beam
last--contains the weaver's lease, and when the completed beam is
removed from the beaming or winding-on frame, this single-thread
lease enables the next operative to select the threads individually
and to draw the threads, usually single, but sometimes in pairs, in
which case the lease would be in pairs, through the eyes of the
camas or HEALDS, or to select them for the purpose of tying them to
the ends of the warp in the loom, that is to the "thrum" of a cloth
which has been completed.
Instead of first making a warp or chain on the warping mill, or on
the linking machine, and then beaming such warp on to the weaver's
beam or loom beam as already described, two otherwise distinct
processes of warping and beaming may be conducted simultaneously.
Thus, the total number of threads required for the manufacture of any
particular kind of cloth--unless the number of threads happens to be
very high--may be wound on to the loom beam direct from the spools.
Say, for example, a warp was required to be 600 yards long, and that
there should be 500 threads in all. Five hundred spools of warp yarn
would be placed in the two wings of a V-shaped bank, and the threads
from these spools taken in regular order, and threaded through the
splits or openings of a reed which is placed in a suitable position
in regard to the winding-on mechanism. Some of the machines which
perform the winding-on of the yarn are comparatively simple, while
others are more or less complicated. In some the loom beam rotates
at a fixed number of revolutions per minute, while in others the
beam rotates at a gradually decreasing number of revolutions per
minute. One of the latter types made by MESSRS Urquhart, Lindsay & Co.,
Ltd., Dundee, is illustrated in Fig. 29, and the mechanism displayed
is identical with that employed for No. 4 method of preparing warps.
The V-shaped bank with its complement of spools (500 in our example)
would occupy a position immediately to the left of Fig. 29. The
threads would pass through a reed and then in a straight wide sheet
between the pair of rollers, these parts being contained in the
supplementary frame on the left. A similar frame appears on the
extreme right of the figure, and this would be used in conjunction
with another V-shaped bank, not shown, but which would occupy a
position further to the right, i.e. if one bank was not large enough
to hold the required number of spools. The part on the extreme right
can be ignored at present.
The threads are arranged in exactly the same way as indicated in Fig.
28 from the bank to the reed in front of the rollers in Fig. 29,
and on emerging from the pair of rollers are taken across the
stretch between the supplementary frame and the main central frame,
and attached to the weavers beam just below the pressing rollers. It
may be advisable to have another reed just before the beam, so that
the width occupied by the threads in the beam may be exactly the
same as the width between the two flanges of the loom beam.
[Illustration: FIG. 29 WINDING-ON OR DRY BEAMING MACHINE _By
permission of Messrs. Urquhart, Lindsay & Co. Ltd_.]
The speed of the threads is determined by the surface speed of the
two rollers in the supplementary frame, the bottom roller being
positively driven from the central part through the long horizontal
shaft and a train of wheels caged in as shown. The loom beam, which
is seen clearly immediately below the pressing rollers, is driven by
friction because the surface speed of the yarn must be constant;
hence, as the diameter over the yarn on the beam increases, the
revolutions per minute of the beam must decrease, and a varying
amount of slip takes place between the friction-discs and their
flannels.
As the loom beam rotates, the threads are arranged in layers between
the flanges of the loom beam. Thus, the 500 threads would be
arranged side by side, perhaps for a width of 45 to 46 in., and
bridging the gap between the flanges of the beam; the latter is thus,
to all intents and purposes, a very large bobbin upon which 500
threads are wound at the same time, instead of one thread as in the
ordinary but smaller bobbin or reel. It will be understood that in
the latter case the same thread moves from side to side in order to
bridge the gap, whereas in the former case each thread maintains a
fixed position in the width.
The last and most important method of making a warp, No. 4 method,
for the weaver is that where, in addition to the simultaneous
processes of warping and beaming as exemplified in the last example,
all the threads are coated with some suitable kind of starch or size
immediately they reach the two rollers shown in the supplementary
frame in Fig. 29. The moistened threads must, however, be dried
before they reach the loom beam. When a warp is starched, dried and
beamed simultaneously, it is said to be "dressed."
In the modern dressing machine, such as that illustrated in Fig. 30,
there are six steam-heated cylinders to dry the starched yarns
before the latter reach the loom beams. Both banks, or rather part
of both, can be seen in this view, from which some idea will be
formed of the great length occupied. Several of the threads from the
spools in the left bank are seen converging towards the back reed,
then they pass between the two rollers--the bottom one of which is
partially immersed in the starch trough--and forward to the second
reed. After the sheet of threads leaves the second reed, it passes
partially round a small guide roller, then almost wholly round each
of three cylinders arranged °o°, and finally on to the loom beam.
Each cylinder is 4 feet diameter, and three of them occupy a
position between the left supplementary frame, and the central frame
in Fig. 29, while the remaining three cylinders are similarly
disposed between the central frame and the supplementary frame of
the right in the same illustration.
The number of steam-heated cylinders, and their diameter, depend
somewhat upon the type of yarn to be dressed, and upon the speed
which it is desired to run the yarn. A common speed for
ordinary-sized jute is from 18 to 22 yards per minute.
[Illustration: FIG. 30 A MODERN YARN DRESSING MACHINE WITH SIX
STEAM-HEATED CYLINDERS]
A different way of arranging the cylinders is exemplified in Fig. 31.
This view, which illustrates a machine made by Messrs. Charles Parker,
Sons & Co., Dundee, has been introduced to show that if the warps
under preparation contain a comparatively few threads, or if the
banks are made larger than usual, two warps may be dressed at the
same time. In such a case, three cylinders only would be used for
each warp, and the arrangement would be equivalent to two single
dressing machines. The two weaver's beams, with their pressing
rollers, are shown plainly in the centre of the illustration. Some
machines have four cylinders, others have six, while a few have eight.
A very similar machine to that illustrated in Fig. 31 is made so that
all the six cylinders may be used to dry yarns from two banks, and
all the yarns wound on to one weaver's beam, or all the yarns may be
wound on to one of the beams in the machine in Fig. 31 if the number
of threads is too many for one bank.
[Illustration: FIG. 31 DRESSING MACHINE FOR PREPARING TWO WARPS
SIMULTANEOUSLY _By permission of Messrs. Charles Parker, Sons & Co_.]
Suppose it is desired to make a warp of 700 threads instead of 500,
as in the above example; then 350 spools would be placed in each of
the two banks, the threads disposed as already described to use as
much of the heating surface of the cylinder as possible, and one
sheet of threads passed partially round what is known as a measuring
roller. Both sheets of threads unite into one sheet at the centre of
the machine in Fig. 31, and pass in this form on to one of the loom
beams.
It has already been stated that the lower roller in the starch box
is positively driven by suitable mechanism from the central part of
the machine, Fig. 29, while the upper roller, see Fig. 30, is a
pressing roller and is covered with cloth, usually of a flannel type.
Between the two rollers the sheet of 350 threads passes, becomes
impregnated with the starch which is drawn up by the surface of the
lower roller, and the superfluous quantity is squeezed out and
returns to the trough, or joins that which is already moving upwards
towards the nip of the rollers. The yarn emerges from the rollers
and over the cylinders at a constant speed, which may be chosen to
suit existing conditions, and it must also be wound on to the loom
beam at the same rate. But since the diameter of the beam increases
each revolution by approximately twice the diameter of the thread,
it is necessary to drive the beam by some kind of differential motion.
The usual way in machines for dressing jute yarns is to drive the
beam support and the beam by means of friction plates. A certain
amount of slip is always taking place--the drive is designed for
this purpose--and the friction plates are adjusted by the yarn
dresser during the operation of dressing to enable them to draw
forward the beam, and to slip in infinitesimal sections, so that the
yarn is drawn forward continuously and at uniform speed.
During the operation, the measuring roller and its subsequent train
of wheels and shafts indicates the length of yarn which has passed
over, also the number of "cuts" or "pieces" of any desired length; in
addition, part of the measuring and marking mechanism uses an
ink-pad to mark the yarn at the end of each cut, such mark to act as
a guide for the weaver, and to indicate the length of warp which has
been woven. Thus if the above warp were intended to be five cuts,
each 120 yards, or 600 yards in all, the above apparatus would
measure and indicate the yards and cuts, and would introduce a mark
at intervals of 120 yards on some of the threads. And all this is
done without stopping the machine. At the time of marking, or
immediately before or after, just as desired, a bell is made to ring
automatically so that the attendant is warned when the mark on the
warp is about to approach the loom beam. This bell is shown in Fig.
29, near the right-hand curved outer surface of the central frame.
As in hand warping or in linking, a single-thread lease is made at
the end of the desired length of warp, or else what is known as a
pair of "clasp-rods" is arranged to grip the sheet of warp threads.
After the loom beam, with its length of warp, has been removed from
the machine, the threads are either drawn through the eyes or mails
of the cambs (termed gears, healds or heddles in other districts)
and through the weaving reed, or else they are tied to the ends of
the threads of the previous warp which, with the weft, has been
woven into cloth. These latter threads are still intact in the cambs
and reed in the loom.