This tie-up contains in its principle the foundation of all the others.
Three methods are in common use, which we will now explain.
1st. The Jacquard Harness threaded on the machine in the direction from
Front to Rear.
This tie-up is represented in Fig. XXV.
[Illustration: Fig. XXV.]
As mentioned in the heading of this article, the Jacquard harness,
or the leashes, are fastened to the machine in rotation from front
to rear, the threading of the comber-board being done from rear to
front. The comber-board is in three divisions. The machine used for
illustrating is a 400 Jacquard 8-row machine, and the comber-board used
is also 8 rows deep. This method of tying-up of the leashes forms what
is technically known as “open harness.” As the drawing is designed to
explain a 400 machine, 8 rows drawn in the comber-board, also 8 rows
deep, one row in height of the cylinder will equal one row in depth on
the comber-board. In examining the illustration the eye must follow the
line connecting the numbers on the neck-cords to the corresponding
numbers near the holes on the comber-board. If this be done, the
tie-up will readily explain itself. It will also explain the method of
procedure if a machine is used containing a different number of needles
and hooks, and a comber-board having as many rows in depth as there
are griffe-bars in the machine. For example, a 600 machine, with 12
griffe-bars, needs for this tie-up a comber-board 12 rows deep; and a
200 machine, with 8 griffe-bars, requires a comber-board 8 rows deep,
etc., etc.
[Illustration: Fig. XXVI.]
The drawing shows a comber-board with 3 divisions, each division
furnishing one harness-cord to each neck-cord, making in all three
harness-cords to every neck-cord. The same tie-up will apply should the
drawing contain a different number of divisions. The illustration shows
only the first and last rows of each division in the comber-board, and
also the first and last rows of neck-cords.
The design below the drawing represents a damask fabric to be executed
on this tie-up, requiring the whole number of needles for one repeat
of the pattern of 400 threads. In designing for these tie-ups it is
necessary to arrange the design to repeat itself in the number of
needles that will be used in producing the fabric. The first and last
threads must connect with each other, without interruption, forming
a continuous design over all the divisions. Thus we find, in fabric
design of a damask towel, Fig. XXVI., the repeat (division) from _A_
to _B_. In the centre of the design marked _a_, and the main part of
the border marked _c_, we find one repeat; whereas borders _b_ and _b´_
repeat 8 times.
In the fabric illustrated by design, Fig. XXVII., again a damask
towel, the repeat, or one division, is also indicated by _A_ to _B_.
The centre of the fabric, _a_, repeats twice in one division; borders
_b_ and _b´_ repeat four times in the same distance; whereas the main
design of the border indicated by _c_ requires one complete division.
[Illustration: Fig. XXVII.]
2d. The Jacquard Harness threaded on the machine from Rear to Front.
[Illustration: Fig. XXVIII.]
This is the second method for the straight-through tie-up, and is
illustrated in Fig. XXVIII. The Jacquard harness is fastened to the
machine, at the neck-cords, from rear to front. The threading of the
comber-board is also from rear to front. In this method the work of
attaching the leashes to the neck-cords is commenced in the rear
instead of the front of the machine, thus giving a different view and
arrangement of the tie-up. This disposition of the threads is called a
“sectional harness arrangement.”
The illustration shows a 400 Jacquard or 8-row machine, in connection
with an 8-row deep comber-board, with one row in the comber-board
requiring a corresponding row on the face of the cylinder. It will also
explain the method of procedure with this tie-up in Jacquard machines
with comber-boards of different sizes.
Fig. XXIX. represents the perforated board at the bottom of the
machine through which the neck-cords pass, attaching the leash to the
neck-cords. The first row, containing neck-cords numbered 1, 2, 3,
4, 5, 6, 7, and 8, and the 50th row, containing those numbered 393,
394, 395, 396, 397, 398, 399, and 400, are the only ones shown in Fig.
XXVIII. illustrating the tie-up. The comber-board is divided into
four sections; hence, the drawing, as represented in Fig. XXVIII.,
calls for a fabric with 1600 ends in width. 400 ends, or any number
dividing into 400, can be used for the repeat of the pattern. The
method followed in the illustration may be applied to any size of
Jacquard machine, and also to any required number of divisions in the
comber-board.
[Illustration: Fig. XXIX.]
In ascertaining the number of hooks or needles for one repeat of the
design, determine accurately if the repeat of the weave employed for
binding _the ground_ or the figure divides evenly into this number. For
example, take bottom board, Fig. XXIX., calling for 400 hooks and 400
needles. Suppose the ground weave to be an 8-leaf satin, and the design
to repeat once in the 400 hooks. 400 ÷ 8 = 50 repeats, showing an equal
division But suppose a 12-leaf satin is used; it is obvious that 12 is
not an even factor of 400, as the division shows a remainder of 4. To
dispose of this remainder two methods are open:
First. Omit last 4 ends and use only 396 hooks, a multiple of 12,
giving 33 repeats; or,
Second. Add 8 hooks from the reserve rows, elsewhere previously alluded
to, thus increasing the number to 408, which is also a multiple of 12,
giving 34 repeats.
3d. The Straight-Through Tie-up on the English System.
The English system, which is widely used, has the Jacquard machine so
adjusted upon the loom as to have the cylinder lengthways, running in
the same direction as the comber-board; or, what is the same thing,
running in the direction of the width of the fabric. [See Fig. XXX.]
[Illustration: Fig. XXX.]
The 8 hooks of one cross-row (one hook from each of the 8 griffe-bars)
run in the direction from the cloth beam towards the warp beam.
Having the same number of rows in depth, in comber-board as there
are griffe-bars, one may readily see the advantages of this tie-up.
The first row in depth of the comber-board contains harness-cords
from neck-cords 1 to 8. The second row deep of comber-board contains
harness-cords from neck-cords 9 to 16, finishing each division on the
last (25th) row, with harness-cords from neck-cords 193 to 200.
Should we have a 600 machine, with 12 rows, the comber-board would also
have 12 rows, as the 600 machine contains 12 griffe-bars. The first row
of the comber-board receives the harness-cords from Nos. 1 to 12; the
second row from Nos. 13 to 24, and so on, finishing on the last (50th)
row of comber-board with 589 to 600.
II. Straight-Through Tie-up for Repeated Effects, in one Repeat of the
Design.
This method of arranging the tying-up of the Jacquard harness is based
upon the necessity for producing patterns having a larger number of
warp-threads than the Jacquard used has needles. The principle to be
observed is found in producing small effects which repeat themselves in
the general design.
The number of cords for the leashes depends upon the frequency with
which these repeats occur. Fabrics with stripe effects offer greater
opportunities for reducing the number of hooks and needles than other
designs. Fig. XXXI. illustrates such a design with its tie-up, using
a 400 Jacquard machine with 8 rows. The pattern shows four distinct
effects, as follows:
_A_, requiring rows 1 to 16, inclusive; or harness-cords 1 to 128,
inclusive.
_B_, requiring rows 17 to 21, inclusive; or harness-cords 129 to 168,
inclusive.
_C_, requiring rows 22 to 34; or harness-cords 169 to 272, inclusive.
_D_, requiring rows 35 to 50; or harness-cords 273 to 400, inclusive.
In this fabric we find 2 full repeats of the design: first, _E_ to
_F_; second, _E´´_ to _F´´_, thus requiring two divisions in the
comber-board, as indicated by the vertical line between _F_ and _E´´_.
[Illustration: Fig. XXXI.]
The next subject to consider is the different arrangement of repeated
effects in one division. Commence at the left-hand side of the fabric
sketch with effect _A_, which repeats only once in one pattern or one
division. The illustration shows two divisions, and also that each hook
of rows 1 to 16, inclusive, in the first division can be connected with
each hook of rows 1 to 16, inclusive, in the second division, because
these rows produce the same effect in the design, which repeats itself
in these two places. This connection forms what is technically called a
leash, and it will always be found that for every harness-cord a leash
contains, there will be found a repeat in the design to correspond.
Effect _B_ is repeated four times in the design, or in each division.
By having two divisions for the illustration we find that to produce
the necessary repeats in the design each hook of rows 17 to 21,
inclusive, requires 8 harness-cords to each leash.
Effect _C_ repeats twice in one pattern or one division. Having two
divisions for the illustration, each hook of row 22, including row 34,
requires 4 harness-cords to each leash.
Effect _D_ repeats once in pattern, once in division. This will give a
result similar to _A_, two divisions, row 35, including row 50, with
two harness-cords to each leash. This tie-up illustrates the first row
of every effect, and also the last leash, 400.
Adding the number of warp-threads in the full repeat of the pattern, we
have:
Effect A = 128 threads.
" B = 40 "
" C = 104 "
" B = 40 "
" D = 128 "
" B = 40 "
" C = 104 "
" B = 40 "
----
624 threads.
Or, in other words, we are producing with a “straight-through tie-up
for repeated effects” on a 400 Jacquard machine, a design, which would
require a 600 machine on a common straight-through tie-up, including
the two reserve rows, or 624 needles; in other words, a saving is made
of 224 needles in one full repeat of the pattern.
In designing for looms tied up for similar styles, the repeats of
effects must be kept in mind. The general style of every design may be
changed, but the arrangement of the repeated effects cannot be altered
without changing the entire Jacquard harness.
III. Straight-Through Tie-up of a Jacquard Loom having Front Harness
Attached.
As mentioned in the beginning of this work, every Jacquard machine
contains two reserve rows, which may be used for various purposes.
One of the purposes to which these rows are frequently put is the
enlargement of the design of the fabric by using harness on the front
of the comber-board, technically known as “front harness.” For example,
in damask table-cloths, we may use the Jacquard harness for producing
the border of the fabric. The centre part may be produced with front
harness, forming a checkerboard, or some similar effect. This process
may be reversed by designing the centre of the table-cloth for the
Jacquard harness, and the border for the front harness.
[Illustration: Fig. XXXII.]
A third method is to design part of the centre and part of the border
for the Jacquard harness, the other parts being designed for the front
harness. This tie-up is also used to a great extent in the manufacture
of dressgoods, etc., where stripe effects produced by the front
harness, alternate with floral or geometrical designs produced by the
Jacquard harness.
In Fig. XXXIII. the centre of a table-cloth cover is shown to further
illustrate this method of tying-up. One-half of the width of the design
is for the Jacquard harness; the other half is for the front harness.
To produce the required checkerboard effect these front harness are
used here in two distinct sets.
The 1st set = 5 harness, working on the 5-leaf satin warp for face,
alternating with the
2d set = 5 harness, working on the 5-leaf satin filling for face.
If only 8 front harness should be used for the design, we should have
the
1st set = 4 harness, working on the 4 harness broken twill warp for
face.
2d set = 4 harness, working on the 4 harness broken twill filling for
face.
Set 1 to alternate with set 2 to form the check. Care must be taken
that the number of checks formed by the front harness are evenly
arranged to the figured part of the fabric. For example, Fig. XXXIII.,
in the front harness part of the design shows 5 warp checks and 5
filling checks in one row, = 10 checks.
[Illustration: Fig. XXXIII.]
Suppose 10 front harness are used and 20 warp-threads allowed for each
check; then 20 × 10 = 200 warp-threads, all used for effects by the
front harness.
This requires 200 warp-threads for figure effects to be used by the
Jacquard harness.
The repeat of the pattern is therefore 400 warp-threads, which is
produced by straight-through tie-up, front harness attached, with 200
hooks and needles for FIGURE PART of the design, _plus_ 10 hooks and
needles for CHECKERBOARD PART of the fabric taken from the 16 hooks and
needles of 2 reserve rows, leaves 6 hooks and needles for selvedge, etc.
As previously stated, the front harness may be used for dressgoods
fabrics. In this way the design may be enlarged to any required extent.
Fig. XXXII. illustrates this method, using an 8-row Jacquard machine,
with 4 front harness adjusted, in common use for the manufacture of
dressgoods fabrics, damasks, etc.
[Illustration: Fig. XXXIV.]
Fig. XXXIV. shows a fabric designed for dressgoods forming an
all-over-set pattern. In this design parts _F_ and _F´´_ must be
executed with the Jacquard leashes; parts _G_ and _G_ can be executed
with front harness. For example: parts _F_ and _F´´_ require each 100
hooks, the ground part to be woven in 4 harness broken twill. We find
the answer as to number of warp-threads in the repeat and number of
hooks required for weaving as follows:
_F_ = 100 threads.
_G_ = 100 " (because covering the same distance as _F_
in part of the fabric.)
_F´´_ = 100 "
_G_ = 100 "
---
400 warp threads in repeat.
_F_ = 100 hooks.
_F´´_ = 100 "
---
200 hooks for figure.
4 hooks for weaving the ground, front harness.
---
204 hooks required to weave design, Fig. XXXIV.,
repeating with 400 warp-threads.