_SPECIAL JACQUARDS AND HARNESSES_
CROSS-BORDER JACQUARDS
A difficulty has always existed in working cross borders on
handkerchiefs, cloths, &c., so as to avoid having to shift or change
the cards, and also to do without the expense of getting a complete
set of cards cut for the whole cloth. It may be also that different
patterns are required on the cloth, such as cross bands of small
figures, and if, say, twenty cards would make a repeat of one figure,
and it was required to weave, say, 100 repeats of this, and then change
to, say, fifty repeats of some other figure, the same difficulty would
arise as with cross borders. When there is only a short distance
between the changes of pattern, it will generally be found more
profitable, all things considered, to have the complete set of cards
cut, so as to require no changing, particularly if the pattern will
run for a length of time; but when the patterns or cloths are long,
the cards become very expensive, and even if it would be desirable to
get a complete set for the full cloth, it may be that there would not
be space on the looms to hold them, over 15,000 cards being sometimes
required to weave a complete tablecloth.
Many methods have been adopted to remedy the inconvenience and to
save expense. A few of them will be given, but it must be left to
manufacturers to judge whether they would prove an advantage to them or
not.
For weaving cloths or curtains it is a common practice to have the
cross-border cards and one repeat of the centre pattern cut. The card
rack is made as in No. 2 (Fig. 99).
When either the border or centre cards are working, they are put into
the hollow part of the rack or card frame, as at F, and the other set
is hung on the flat rest of the frame, at either D or E. When a change
is to be made, a card-shifter has to go up and change from one set to
the other, lifting the set that had been working out of the hollow
of the frame, and putting it back or forward on the rest D or E, and
bringing the set which is to work down into the place of those removed.
This, of course, is expensive, gives a great deal of trouble, and is
severe on the cards; at the same time, in many cases it is found to
answer as well as any method yet adopted, particularly where space is a
consideration, and when two or more sets of cards are used, in case of
two or more machines.
[Illustration: Fig. 99]
A better plan is to have a sliding-card frame, as shown in No. 1 of
the same figure. A is the frame for the rollers over which the cards
travel, B, B are two bars on which the card frame C, with the roller
frame A attached, travels. The card frame is only shown in end view.
Two of these must be for each set of cards, and the whole frame must
be fastened together complete for all the cards required, so that it
will all slide on the bars B, B. Suppose there are two machines working
there must be four card racks; on two of these the centre cards are
hung, and on the other two the border cards. Either set can be placed
opposite the cylinders of the jacquard, and wrought as long as is
required; then they must be taken off the cylinders, the card frame
shifted till the other set of cards comes into their place, when they
can be put on the cylinders and wrought over. This is a very good plan
for working long cloths, but takes up a good deal of space, and for
more than two machines might in many cases be unsuitable.
[Illustration: Fig. 100]
Another method is to have two sets of card irons, one above the other;
the border cards are hung on the lower frame, and the centre cards on
the upper one. The centre cards will work in the usual way, and when
the border is to be wrought the cards for it are taken round the centre
set, which, of course, are taken off the cylinder. The rollers must be
made to shift so as to direct the cards properly into their respective
frames; the top frame is smaller than the bottom one, and farther out
from the machine. If hooks and eyes are sewn on the first and last
cards of these sets, the weaver can hook them together when a fresh
pattern is required, so that the one set will carry the other round the
cylinder. Then, by drawing a cord, the rollers should change position
so as to direct the falling cards into the proper frame. The card irons
are of the usual shape, and the distance between the upper and lower
ones may be regulated by circumstances.
Another simple method is to have the card frame made with a double
curve in it, as shown in Fig. 100. One set of cards hang in each of
these curves, as at A and B. The set in the curve A can be wrought over
as long as required; then these cards can be taken off the cylinder
and the set at B put over it. One thing must be observed: that the
frame and rollers be so placed that the cards can be guided into the
receptacle B, and to do this there must be a considerable fall for
the cards, so that for a loom with a low framing this might not be
feasible. Otherwise, it is a simple method of arranging two small lots
of cards, and if one lot is much larger than the other, let A be a
narrow curve, and the small lot of cards hang in it, which will lessen
the slant of the cards falling to B.
Although such arrangements as the foregoing are required where there
is much machinery used, it is evident that for frequent changes they
would take up quite too much time. Several machines have been made
for the purpose of changing from one set of cards to another without
having to move the cards. The principle of these machines is to have
two cylinders, one at each side; one set of cards is placed on one
cylinder, and the other set on the other cylinder, so that by working
one or other cylinder, as required, either border or centre may be
woven. No. 1 (Fig. 101) shows a plan that was tried some time ago,
but did not work satisfactorily. The needles passed through a needle
board at each side of the machine, as at A and B, and had small spiral
springs fastened on them inside the needle boards. The border cards
could be put on the cylinder at A, and the centre cards on that at B.
The cylinder at A could be wrought as a single-acting machine till
a change of pattern was required; then the cylinder at B could be
brought into action, and that at A remain stationary and clear of the
needles. The heads of the hooks were made heart-shape, as shown, and
the blades of the griffe could revolve into the position shown by the
dotted lines, so as to suit the working of the cylinder at B; this was
effected by the weaver pulling a cord. This machine was given up, as it
was difficult to keep it in order.
Another method is shown at No. 2 (Fig. 101), where there are two
griffes--one at F, and the other at G; one cylinder works at E, and the
other at D. Only one set of springs is required on the needles--behind
the needle board E--as the spring of the hooks is sufficient to act in
the opposite direction. When the cylinder D is working the lower griffe
is stationary, and when the cylinder E is working the upper griffe
is stationary. The cylinders and griffes are brought into action as
required by suitable mechanism. This machine has not been considered
sufficiently successful to make it worthy of being persevered with.
[Illustration: Fig. 101]
[Illustration: Fig. 102]
The principle of Davenport & Crossley’s border jacquard is shown in
Fig. 102. The upright hooks are as in an ordinary machine. Four of the
needles are shown at _b_, and are made in the ordinary way, with the
exception of the eyes in them for the small upright needles _d_ to
pass through. These needles _d_ are connected with a set of horizontal
ones, as shown at _a_, and act as levers between them and the needles
_b_, the bars behind them serving as fulcrums; so that when the needles
_a_ are pressed back by the cards, the needles _b_ are also drawn back
through the medium of the uprights _d_. The cards least in action are
put on the cylinder for the needles _a_, and the others act on the
needles _b_. The cylinders can be brought in or out of action by the
motion shown at A, B, C, D, E, F, G. A and B are the cylinders, working
on swing motions; C A, D B, are connecting-rods for giving motion to
the cylinders; either of these can be brought into action as required.
G is a rocking lever carrying a stud on each end, which work in the
slots C and D; these slots are shown at D^1 where the notch at one side
of them will be clearly seen. When the stud on the bar G gets into
this notch, the cylinder will be driven out and in, but when not in
the notch the stud can slide along the slot, allowing the cylinder to
remain stationary. By pulling the cord H either cylinder can be wrought
as required through the connections shown, one of the connecting-rods
being raised and the other lowered. F, E are the levers for driving the
rocking bar G. This machine works very well, though the principle of
its construction is not all that could be desired, and it requires a
considerable space. It can be made a double-lift machine by having two
hooks to each needle and two griffes as in the ordinary double-lift,
single-cylinder machine.
[Illustration: Fig. 103]
The principle of Devoge’s border jacquard is shown in Fig. 103. C C is
the rocking bar, for driving the cylinders, working on the centre D.
It is driven by the levers F, G, and the connecting-rod E. The notches
A and B fall over the studs on the cylinder frame, and can either be
let down or raised, as required, by the cords K, L and the levers H, I.
The machine is an ordinary double-cylinder one, and either griffe can
be wrought to suit the cylinder that is in action. This machine can be
used as an ordinary double-acting one, as a single-acting one raising
both griffes together and bringing in both cylinders together, or as a
border machine working one griffe and one cylinder at the same time.
Another method, similar to the above, is to have a double-cylinder
machine with the cylinders wrought by the griffes, then have a stud
on the crank-shaft wheel for raising one griffe, as for an ordinary
single-acting jacquard, and the two connecting-rods from the griffes
made so that either will work on it. A hook or catch can be put in any
convenient place, so that when one connecting-rod is on the stud the
other can be hooked out of the way. The rods can be made to slide on
to the stud easily, and be fastened with a pin, so that the weaver can
readily change from one to the other.
OPEN-SHED JACQUARDS
To obviate the vibration of the harness as much as possible, as well as
to economise the wear and tear of it and to minimise the friction on
the warp threads, especially in weaving patterns requiring heavy lifts,
such as warp-faced patterns, Messrs. Priestley & Co., of Bradford,
patented an open-shed jacquard, the principle of which is shown in Fig.
104. It did not, however, prove successful, as the tacklers found some
difficulty in working it.
The machine is an ordinary double-lift jacquard with one cylinder, and
works in the ordinary way. The hooks are made as in Fig. 104, where
it may be observed there is a turn or catch on the lower portion of
the hook, at A. Above these catches is a set of bars, _b_, like a
stationary griffe, and when the hooks are raised by the upper griffe,
in the ordinary way, they spring over these lower bars and rest on them
when the griffe begins to fall. All the hooks raised would thus remain
up, were it not that the cylinder, pressing in for the second griffe
(the machine being double-acting), which begins to rise as the upper
one begins to fall, presses back those hooks that are not to be raised
for the following shot, and as they are held by the griffe above, they
spring back at the bottom, and, clearing the bars _b_, come down with
the falling griffe. In this way the hooks, when once raised, remain up
till pressed off by the card, so that in the case of working a warp
stripe with an 8-leaf satin binding the hooks would only fall for every
seventh pick.
[Illustration: Fig. 104]
[Illustration: Fig. 105]
Another machine has since been tried, but did not work satisfactorily.
In this machine the lifting hooks are formed with loops or hooks, in
addition to the top hooks. The hooks are lifted in the ordinary way
by the griffes; and upper knives, made to reciprocate horizontally,
catch the raised hooks and support them. By suitably timing the motions
of the card cylinder the hooks may be kept up as long as required by
being transferred from one set of knives to the other. The shape of
the hooks and needles is shown in Fig. 105. The needles may be as at
_b_ or _b^1_. This machine acts as an ordinary double-lift jacquard,
but has only one set of needles, which pass through needle boards at
each side of the machine, and are acted upon by two card cylinders. No
springs are required, the hooks acting as springs to keep the needles
in position. The cylinders are driven by a tappet, and can be held
against the needles as long as required; one cylinder must press on
them when the griffes are passing, so as to prevent those hooks which
are descending from being taken up by the ascending griffe. There are
two griffes; three of the knives of the one are shown at 1, 3, 5, and
three of the other at 2, 4, 6. When these knives lift the hooks by the
lower loops or hooks on them, they deposit them on to a set of knives,
_a_, _a_, _a_, _a_, in an upper grid or grating, which has a lateral or
horizontal motion.
The lower knives raise the tops of the hooks slightly above these upper
knives, so as to clear them, and the upper grid is then moved sideways,
taking the knives from under one set of heads of the hooks and placing
them under another set. Each time the griffe rises all the hooks not
acted upon by the cards will be deposited on the upper grating, and
will be transferred from one knife to another at each lift, till the
card acting upon the needles keeps them clear of the upper grating
and allows them to fall with the descending griffe. In this machine
the tugs or tail cords, as used with double-lift machines, are not
required, the double hooks serving for two single ones. Other efforts
have been made in this direction, but the plan of using small pulleys
on the tail cords, between the pairs of hooks, to which the neck twines
are hung, is the only one worth mention. The same principle will be
found for working the shafts in Fig. 115, and is more suitable for a
few shafts than for 400 to 600 hooks, or pairs of hooks.
THE VERDÔL JACQUARD
Everyone accustomed to work large patterns on jacquards, especially on
power looms, must have found the inconvenience resulting from a large
set of cards. The space taken up, the time and trouble required for
changing them, to say nothing of the cost, have been sufficiently felt,
but have hitherto had to be borne with as a matter of necessity.
For working fine tablecloths with from 150 to 180 picks per inch, or
for curtains where from 3 to 6 cards are required for each weft line of
the design, and when from 2 to 4 jacquards are used, the inconvenience
and cost of a set of cards ranging from 10,000 to 50,000 are very
considerable. The small jacquards described at Fig. 30 make a great
saving in the space taken up by the cards, as well as in the quantity
of card paper used; but it has been thought that a still greater saving
could be effected.
[Illustration: Fig. 106]
M. Verdôl, of Paris, has for a length of time been endeavouring to
perfect a system of substituting a continuous roll of perforated
paper for the cards, and has succeeded in doing so, though it is
doubtful if he will be so far successful as to supersede our present
method of working. These machines were taken up by Benson’s Patent
Jacquard Company, of Belfast, in the year 1876, but did not then give
satisfaction, the greatest obstacle in the way being the effect of
the atmosphere on the paper; and as the needles are very closely set
together, it was found impracticable to keep the paper set so as to act
correctly on them. This difficulty is now claimed to be overcome by
having procured paper which is said to be less liable to be affected by
the atmosphere than the brass plates of the machine. Several of these
machines have been tried in Scotland, but it will take some time to
prove them thoroughly and get the workmen accustomed to them, as they
are much finer than the jacquards in general use.
The Verdôl machine consists of a small jacquard, the ordinary French
make of machine, which is usually made with 440 and 880 hooks for the
single and double machines respectively. In addition there is a frame
or box attached to the front of the machine, against the needle board,
containing another set of horizontal and vertical needles or wires,
which act upon the ordinary needles of the jacquard, according as they
are acted upon by the perforated paper. Fig. 106, Nos. 1, 2, and 3,
shows the principle of the machine. B, B show the needles, and D, D
the uprights or hooks of the ordinary jacquard; only four of each are
given, but sixteen are used. N is the face-plate or needle board, and
O is the clap-board used for bringing back the needles, which have no
springs on them; but the hooks are turned up double, and the back or
turned-up portion of them, coming against horizontal wires or bars,
shown in section above the needles, acts as a spring to keep them
steady. This portion of the machine is a complete jacquard of the
ordinary French make. In addition to this there is the apparatus on
which the perforated paper acts, and which communicates this action
to the jacquard. It consists of a box or frame containing two sets of
wires--one set horizontal, as A A, about 6 in. long, and terminated at
one end by a small head, as shown separately at A^1, which are called
hitting wires. The other set is vertical, as C C, of fine wire, having
a loop on one end, by which they are suspended in a frame, and a loop
in the centre, which passes round the horizontal wires. These are
called the vertical needles or feelers; one of them is shown separately
at C^1. The points or lower ends of these needles pass through a
horizontal brass plate, G, called a guide-bar. The hitting wires pass
through a guide-plate, M, placed so that their heads will come exactly
against the points of the needles in the jacquard, as shown in the
figure. The other ends of the hitting wires lie loosely in the loops
of the vertical needles, C. Underneath the guide-bar G is the curved
brass plate I, which is in lieu of a cylinder. Between the cylinder and
the guide-bar G the perforated roll of paper I I passes; there is just
sufficient room between them for it to pass freely through, as it is
moved forward by the stud wheel K. The paper may pass from one cylinder
or reel to another, or may hang in folds in the same way as cards
usually hang. At the points of the hitting wires is a grid or pushing
frame, H, with an iron angle-bar across above each row of wires, as
shown in section in No. 1 at H. There is a clap-board above the small
vertical needles, which is shown raised at E in No. 1, and down in No.
2; this is raised and lowered with these needles, and serves to bring
them all down when raised. E^1 shows the way in which these needles
are hung in the frame that supports them. When the machine is working
the frame H has a horizontal traverse coming against the ends of the
hitting wires when they are pressed up by the card on the cylinder,
and, pressing them against the needles of the jacquard, push them back
as an ordinary card cylinder would. It may be seen in No. 1 that two
of the feelers are down and two are pressed up, as they would be if
two holes were cut in the paper and two uncut; the two that are up
raise the hitting wires connected with them, and it will be observed
that this raises the points of the hitting wires so as to come against
the angle-iron of the grid H when it is coming forward; whereas the
two hitting wires that are not raised will pass through, and not be
pushed back. This enables the card paper to act on the needles of the
jacquard in the same way as if coming directly on them, as cards do.
The cylinder has a slight vertical motion, rising about 1/8 in. The
needles, when the cylinder is down, do not pass through the plate G; it
is perforated through and raised by the cylinder ascending. When the
frame H is pressed forward the clap-board O is pressed back.
The card paper is of a special make, thin and tough, and is
strengthened along both sides and in the centre by strips of paper
pasted along it where the stud holes fall. No. 3 shows the motion by
which the clap board E is raised and lowered by the sliding of the
cranked bar F between the two studs 2. No. 4 shows the size and pitch
of the holes in the hard paper. These are traced from the paper,
and lie diagonally, two rows of 8 making one row of 16 hooks in the
jacquard.
These machines are working in large numbers in France, and appear to
give more satisfaction there than here, partly because they are better
known, and the French workmen are better adapted to handle the small
parts belonging to them. A coarser machine is more suited for the
ordinary workmen to be found in the factories of this country. But it
is strange if a machine of a pitch about half-way between the French
jacquards and ours would not be better than either; not taking up so
much room as ours, and not so minute as the French. However, in many
cases the machines we have in use are none too large to give sufficient
latitude for the errors often found cropping up in work, none of which
should occur, of course, though they often do, through carelessness
or otherwise. For instance, the card cylinder may be a little off the
pitch, and the cards may be affected by damp, or may not be correctly
cut to suit the cylinder; the points of the needles may be a little
bent by the cylinder, or by the carelessness of the weaver when turning
back her cards, and the cylinder may not be set quite fair for the
needles. Mr. McMurdo, of Manchester, has made a very nice machine of
the same pitch as the French ones, with 1,296 hooks, 16 row cards. It
works as a double-acting machine with two cylinders and two griffes,
but only one set of needles acting on the two sets of hooks. Two of the
hooks are shown in Fig. 107; each needle clasps two hooks and passes
through a needle board at each side of the machine. There is no spring
on the needle, the hooks forming the spring, the tops of the hooks
coming against the cross-rods at A A. Otherwise, this machine works in
the usual way, and is very compact where a large number of hooks are
required in a small space.
[Illustration: Fig. 107]
The card-cutting machine used for the French system of work is a very
elaborate contrivance, being more like a jacquard loom than any of our
card-cutting machines, at least in so far as the harness is concerned.
The principle of it is seen in Fig. 108. a shows the set of cords by
which the punches are wrought. The method of preparing the pattern
to attach to these cords has been referred to before, but will be
repeated again further on. These cords pass over the pulleys B and
down through a reed to the lingoes C, which keep them in tension.
Another set of cords pass from these over the pulleys D and down to the
punches F. When any of the cords at A are drawn the punches connected
with them are dropped, as raising the lingoes lets the cords pass over
the pulleys D. When a punch is let fall, it is caught by one of the
angle-irons of the grid G, which is pressed forwards when a card is to
be cut. The card paper is on the roller JH, and passes down in front
of the punches at I, which, when pressed forward, punch the paper
between them and the block K. Any punches that are held up pass through
the grid over the angle-iron bars. Only four punches are given, but
sixteen are used in the machine; they are here drawn out of scale to
show them more clearly. This portion constitutes the cutting machine;
it is worked by two persons, one behind, to draw the cords, and another
in front, to punch the paper by depressing a treadle each time a draw
is made. In addition to cutting from the pattern the paper can be cut
from other sets of cards, as in a repeating machine--cut either on
the English or French system. N is the French machine, and a set of
cards can be put on it and copied, the cords O acting on the punches;
English-cut cards can be put on the machine at L and copied, the cords
M acting on the punches. Of course, when one portion of the machine is
working, the other parts remain idle, and it might be better to have
them separate if much work is wanted.
The pattern is prepared for this machine by hand, working one repeat
of it as follows:--The design, painted on point paper, is placed on a
frame in an upright position, and over each line on it is stretched a
vertical cord, which is taken as warp. The picker then takes a bobbin
of weft and inserts it under every cord that passes over a painted dot
on the first weft line of the pattern, keeping it in front of all the
cords that pass over blank spaces, just in the same order as a shuttle
would pass through if the shed were to be opened by a jacquard. When
this is done the next line of the design paper is picked similarly,
and so on, till a complete repeat of the design is loosely woven with
cords, which are made of well-twisted harness twine. This process is
somewhat similar to reading the pattern for the draw loom, _which see_.
For coloured work a shot would require to be worked in for each colour
on any weft line, the same as it is to be woven. When this is prepared,
it is taken to the cutting machine and the warp tied to the cords A,
the weft showing the warp ends to be drawn for each card.
[Illustration: Fig. 108]
HALF HARNESS AND MUSLIN HARNESSES
So far we have been speaking entirely of ‘full-harness’ work. Though
the principle of mounting is much the same in all classes of harnesses,
there are certain deviations peculiar to each.
One drawback to the full harness is the amount of machinery required
to give a large extent of pattern, an upright hook and a needle being
required for each thread in one repeat of the pattern. In a half
harness only half the amount of machinery is required on the same
fineness of cloth to give an equal extent of pattern; but it is only
for a few classes of goods that this method of working is suitable,
leno curtains and muslins being the principal. Leno curtains will be
mentioned under gauzework, as they are wrought with a gauze mounting,
but on the half-harness principle. Figured muslin curtains, with a
plain ground and coloured flowering, are called ‘crêtes,’ or ‘crête
curtains’; these are now generally wrought in a full harness. Figured
muslins are much of the same class of cloth, but are not figured with
colour and tint for the half harness, known as the ‘common spotting
harness,’ or ‘book harness.’ For working them the harness is mounted in
the ordinary manner, but only half as many cords are required for it
as there are threads of warp. Only half of the warp is drawn into the
harness, the other half--every alternate end--passing through it, and
being drawn into a plain leaf of heddles, which is hung close in front
of the harness. In fine work two leaves of heddles may be used as one,
to prevent crowding.
The ground of the cloth is a plain texture, and was formerly wrought by
having two leaves of long-eyed heddles in front of the harness, into
which all the warp was drawn, this probably being more convenient for
the hand-loom weaver; and besides, a more even plain ground can be made
with the heddles than with the harness and one leaf of heddles. Two
shots of ground, or fine weft, are given to one shot of figuring, or
coarse weft, usually cotton rove; but to avoid using a pick-and-pick
loom when working by power, the coarse shot may be made by throwing two
finer ones into the same shed. In power looms the ground is wrought by
raising the plain leaf of heddles and all the harness alternately, and
the figuring shed is formed by drawing the harness with a card acting
on the machine. The pattern is painted solid, without any twilling or
binding on either ground or flower, so that the figuring shot will be
in a plain shed for the flower, but will be loose or unbound over the
ground, and is afterwards cut off in a cropping machine.
[Illustration: Fig. 109]
The plain shed, into which the thick weft is thrown, must also contain
the shot of thin weft thrown in either before or after it, according as
the figuring shed follows the plain shed made by raising the harness or
the heddles; for supposing the heddle shaft to be raised and a ground
shot thrown in, then the shed reversed by raising the harness and
another ground shot thrown in, then the figure shed formed by raising
50 or 100 hooks of the harness, this opens portion of the last shed,
and the figure weft will be thrown in along with the last shot of
ground. When both wefts are white this is of but little consequence,
but when using coloured wefts for the figure the ground weft would
be liable to show along with them and injure the pattern. This was
originally overcome by adopting the ‘paper harness’ from the shaft
mounting for weaving paper spots. In this mounting two sets of shafts
and two harnesses are used, one behind the other. Half of the warp--all
the odd numbers of threads--was drawn on the back harness, and the
other half--all the even numbers--on the front harness; this would be
sufficient to make the cloth, but a pair of leaves of long-eyed heddles
were used for working the ground, acting as pressers. On this method
of working, a ground and a figuring shot are thrown in alternately, as
either half of the warp can be raised by the harness for the figuring
shed, and a richer spot is thus given; but still, the rove or figuring
shot would fall into the same shed as the ground shot, which may be
seen by examining the two spots given in Fig. 109, A being wrought
on the common spot or half-harness mounting, and B on the paper-spot
mounting. The grey shots are the ground, and the black ones the figure.
However, in the paper-spot mounting it is not necessary to throw the
rove into a plain shed; any suitable twill may be used for binding the
figure, and will give a much richer effect on one side of the cloth
than plain, and tie down the ground shot, which will go into a plain
shed.
This principle of mounting is now done away with, as it has no
advantage over the ordinary full-harness mounting, which can also have
a pair of presser leaves of heddles in front for working the ground, if
desired; but they are unnecessary in a power loom, except when a very
level ground is required.
A twilled or flushed figure may be formed with the common half harness,
but only having half the warp for binding causes it to be loose and
ragged round the edges.
To work a large pattern, perhaps the most economical way, at least
in the hand loom, is to use a pressure harness with two threads in
the mail, and with four presser heddle leaves in front. The number
of leaves regulates the twill on the figure. The cloth may be woven
pick-and-pick, ground and figure, or 2 picks ground to 1 of figure.
When the harness is drawn for the figure all the heddles must be
sunk but one leaf, and sinking the two front and two back leaves
alternately, raising the back ones when the front ones are sunk, and
_vice versa_, will form plain cloth with the draft 1, 2, 3, and 4 over
the leaves. A 4-leaf twilled figure can be made with this mounting, but
still it will not have the advantage of the full harness, in which the
figure can be varied in twill, and bound round the edges.
SPLIT HARNESS
The term ‘split harness’ is sometimes applied to the pressure harness
when wrought with two threads in the mail, this constituting a splitful
of warp, so that each cord of the harness controls a splitful of warp;
but this is only the finest description of pressure harness.
[Illustration: Fig. 110]
The split harness, or ‘shaft monture,’ was invented in the silk
district of Bethnal Green, shortly after the introduction of the
jacquard, for weaving rich silks which have about 400 threads of warp
per inch, but much less weft--perhaps about one-fifth of that number
of threads. The harness is wrought with the ordinary jacquard, but
there are two mails and lingoes attached to each neck cord, as shown in
Fig. 110. A, A are the neck twines, B is the cumber board, and D the
mails. If this mounting were wrought with the jacquard only, it would
produce the same effect upon the cloth as if two threads were drawn
into each mail of an ordinary harness. This would, of course, take away
the fine appearance of the cloth. To avoid this a set of shafts, C, C,
are passed through loops in the twine above the mails, and are attached
to a set of hooks in front of the jacquard, or at each side of it, or
may be wrought by a separate dobby. Twenty-four shafts are mostly used,
and are usually flat enamelled iron bars. These shafts are for working
the ground of the cloth, and can raise each row of mails separately,
as shown at No. 1 leash, thus splitting the pairs of threads that are
connected with each hook of the jacquard. One or more of these shafts,
according to the texture required for the ground, are raised at the
same time that the jacquard draws the figuring shed. No ground texture
is put on the pattern for the cards, but the figure must be twilled,
or have the binding marks cut on the cards for it. The binding of
the figure will be in pairs of threads--that is, two threads of warp
must sink together under a weft shot, though on the design these two
threads will appear as one, as they are wrought by the same hook of the
machine. On account of the number of warp threads, rising and sinking
in pairs will not much affect the appearance of the figure; though it
must be coarser than if the threads were bound separately, and will
also have a rougher or more ragged outline; but to get a large figure
with so much warp would necessitate a great amount of machinery if the
threads were drawn into separate mails with one to each cord of the
harness.
This method of working is surpassed by the twilling machines now in use
(see Twilling Jacquards), though they are more intricate, and would not
suit well for a hand loom, as they are heavy to draw.
PRESSURE HARNESS
This is the old draw-loom system of working, and, old as it is,
is still in use on our modern hand and power looms on the finest
description of damasks, and is not likely to be surpassed for making
a good piece of cloth. Much firmer than a harness, and producing the
largest possible pattern with the least possible cards, mounting, and
machinery it took up its position in the days of the drawboy, and has
held its own, with the aid of the jacquard, against all the inventions
of modern times. The principal advantage of this system of working
is that a much larger pattern can be produced with the same quantity
of cards, mounting, and machinery, than by any other means; but the
pattern wrought by a pressure harness will not compare with one wrought
by a full harness for fineness of outline or detail. When weaving large
tablecloths with 100 or 120 threads of warp per inch, and from 50 to
72, or even 90 in. in the single pattern--that is, when the pattern
is all, or nearly all, single--the amount of machinery that would be
required to work it on a full harness could not be crowded on a loom,
the French system being the only one by which it might be attempted;
and even then the difficulty of keeping the machinery and cards in
perfect working order would be very great, not to mention the cost of
mounting, patterns, cards, &c. The quantity of harness and machinery
is reduced in a pressure harness by drawing two or more warp threads
into each mail in the harness. Suppose we take 60 in. of cloth with
100 threads per inch = 6,000 threads, and allow 3 threads to each mail
in the harness, or each hook of the jacquard, 2,000 hooks, or four 500
jacquards, would be required to work the pattern. As many as six 600
jacquards are sometimes required on this description of work when very
fine; but three or four 500 or 600 machines are more commonly used on
either hand or power looms. To work one of these finest patterns in
a full harness 10,800 hooks would be required--say, six 600 machines
with 3 threads to each mail = 10,800; and almost double this number
of cards, even with working them backwards and forwards, would be
necessary.
In early times, when the drawboy took the place of the jacquard, 6,
8, or 10 threads were put to each mail, or went to what would now be
one hook of the jacquard; and patterns were not usually so extensive
as they are now, so that the cords of the harness were greatly reduced
in number, but with a proportionately coarser effect of pattern. The
difference between a pattern wrought with a full harness and one
wrought with the pressure or any of the twilling harnesses, is that
the outline is clear and defined in the full harness, and the detail
and points of the figures can be turned on a single thread, whereas
in the others the edges of the figures will be jagged or in steps,
and the points must turn on whatever number of threads are lifted
together. The pattern on the cloth must therefore have somewhat of the
rough, square effect of the design on point paper, though, of course,
reduced in size, but will be worse in this respect--viz. that whereas
the edges of the figure on the point paper are clear and well defined,
on the cloth they are not so, the rough edges to some extent blending
the figure into the ground, and not giving the clean, sharp effect of
a full-harness pattern. Shaded effects are also coarse on a pressure
harness, but can be made effective if broadly treated. Cloth with 100
or 120 threads per inch does very well to have three threads to the
mail, and from 80 to 100 threads per inch suits very well for two to
the mail. Any coarser set than 80 threads per inch requires to be woven
in a full harness to produce good work, and for superior work nothing
less than 100 threads per inch should have two threads to the mail,
though 80 per inch does very well.
When several threads are put to the mail, it is also usual to put
several picks to each card. The fewer picks, the finer will be the
pattern; but a good method of regulating this is to make the checks
formed on the cloth square, a little more or less according to the
fineness of the pattern required. Thus, if the cloth is wefted square,
or a little over that--say, 100 warp by 100 to 110 weft threads per
inch--paint the design on, say, 8 × 8 or 8 × 9 paper, and give as many
shots to the cards as there are threads in the mail. If the cloth is
to be wefted one-half over square (100 × 150) the same pattern will
still do, but with half as many more shots to the card than there are
threads in the mail. If there are two threads in the mail there will
be three picks to the card, but if there are three threads to the mail
there must be four picks to one card and five to the next one. This
would be for a pattern on 8 × 8, or square paper. If painted on 8 × 9
paper, which would give an extra card to every eight, and if the weft
must not be increased, then four or five picks must be taken off the
number given to the eight cards and put to the ninth one, for four
cards with four picks to each and four with five picks to each = 36
picks, and thirty-six picks put to nine cards would allow four picks
to each. This would make the edges of the pattern a little finer; and
if the design was painted on 8 × 10 paper it would be finer still, as
there would be more cards to a given number of picks.
In this way any alteration required can be made on the number of picks
per inch given to cloth woven on a pressure or twilling harness,
without distorting the pattern by varying the number of picks given to
each card to suit the shotting. Neither is it necessary to have the
same number of threads in each mail; the warp might be mailed 2’s and
3’s or 3’s and 4’s, but the more regular they are, the better. If the
fineness of the cloth requires to be altered, it may be woven in the
same harness without any alteration by varying the number of threads
in the mails. For instance, a warp of ninety threads per inch mailed
3’s and one with 120 threads per inch mailed 4’s would work in the
same harness. Similarly, the same set of cards would suit for making
different widths of cloth by making the harness narrower in the cumber
board and altering the mailing so as to keep the cloth the same set, or
it may be made a finer set and not alter the mailing. In either case
the pattern would be reduced in size.
Fig. 111 shows a portion of a pressure-harness mounting which is
similar to that of the draw loom. It is mounted in the same manner
as described for full harness, only that the warp must be divided by
the number of threads to be drawn into each mail in order to find
the quantity of harness required. The kinds of mails used are shown
at A and B, Fig. 111; it does not do to have more than two threads
drawn into each eye of the mail, as they are liable to twist round
each other; two will separate easily, but a greater number will not.
Ordinary full-harness mails answer very well for a two-thread harness.
The mails are levelled in the same position as for full-harness work,
viz. about 1-1/2 in. below the level of the back and front beams for
hand-loom work, and a little lower for power looms. The lingoes are
heavier than those required for a full harness; the weight depends upon
the strength of the yarn and the number of threads in the mail; 10 to
12 to 1 lb. are used in power looms for linen damask with two threads
in the mail, having about eighty to one hundred threads of warp per
inch. For hand looms they are usually made of lead, thicker and shorter
than the wire lingoes, and called ‘leads’; 11 to 15 per lb. suits for
three- or four-thread harnesses. Light cotton work, such as muslin
curtains, only requires lingoes of about sixty or seventy to 1 lb. for
hand looms, but from twenty-five to thirty per lb. are used in power
looms for two-thread harnesses.
[Illustration: Fig. 111]
The principle of working the pressure harness is best explained by the
diaper mounting shown in Fig. 2, where a back set of heddles takes the
place of the harness, and a set of ground leaves of long-eyed heddles
stands in front of the back ones. After the yarn is drawn into the
harness or back mounting in the usual way, it must be drawn into the
front or presser heddles, using, generally, a straight draught for a
satin ground. If Figs. 2 and 111 are examined, it will be seen that
when the shed is opened by the harness or back mounting, the heddles in
front sink part of the raised warp and raise part of the sunk warp. The
mounting raises all the warp of the figuring portion on each card or
line of the design paper, and leaves down all the ground warp, so that
it is necessary to have the heddles in front to bind the warp and weft,
or form the texture of the cloth. For an 8-leaf satin eight shafts are
required; one of these must be raised and another sunk for each shot,
so as to raise the binding threads of the sunk warp and sink those
of the raised warp, the harness forming the outline of the pattern,
or raising the warp of it in a mass. The other six leaves of heddles
stand in a middle position, and the long eyes allow the warp drawn by
the harness to rise. When the machine is drawn it is held up till as
many shots as are to be given to the card are thrown in, but the shed
formed by the heddles must be changed for each shot. In working bars
up the cloth one card would be sufficient, and when the machine is
drawn it would be held so, and the cloth wrought with the heddles; of
course, no machine would be required in this case, one leaf of heddles
with the stripes of warp drawn into it would be sufficient for the back
mounting. For dices two leaves of heddles would be sufficient for the
back mounting, the warp of one dice to be drawn on one leaf, and that
of the other on the other leaf; then one leaf would be raised and held
up till one dice was wrought, when it would be lowered, and the other
one raised and held up for the other dice. For fancy dices and diapers
the plan of mounting in Fig. 2 is very suitable and simple, but for a
variety of figuring or flowering the jacquard is necessary.
It will be seen that the presser heddles have three positions, viz. a
sunk, a raised, and a middle position. The length of the eyes is to
allow the harness to open the shed when the heddles are stationary,
or in their middle position. They must be a little longer than is
required to open the shed at the back leaf of the heddles; for a
2-in. shed a 2-1/4-in. to 2-1/2-in. eye is used. When the heddles are
stationary the lower loop of the eye should be fully 1/8 in. under
the sunk warp, and there should be the same clearance at the top when
the shed is drawn; some allow more. The shed for a pressure harness
is usually very small in front of the reed, and requires a very small
shuttle to be used, from 1/2 in. to 1 in. deep being the usual sizes.
The depth of the shed that can be made depends principally on the
elasticity of the yarn. With a linen warp a very small shed can be
made, as the yarn has but little elasticity, and if overstrained will
hang slack. For it the distance between the harness and the back shaft
of the front mounting should be 10 in. to 12 in., and there should
be a stretch of 27 in. to 34 in. behind the harness. The draw of the
harness may then be 3 in. to 3-1/2 in., and the shed at the back shaft
will be 1-3/4 in. to 2 in.; this will allow a shuttle of 3/4 in. to 7/8
in. deep to be used. For hand looms the shed is about 1-1/4 in. at the
back shaft, and a shuttle of 1/2 in. deep is employed. The shed must
be made very clear and regular, and the smaller it can be kept, the
better. With a good cotton warp 7 in. is a sufficient distance to have
between the harness and heddles, and will admit of a larger shed being
formed; but it is not desirable to have too large a shed, as there is
a considerable strain on the yarn, and a small, clear shed is more
satisfactory. This would be assisted by bringing the harness as close
as possible to the heddles.
One drawback to this method of working is the distance which separates
the harness from the fell of the cloth, or even from the reed; and
if there is any obstruction to the warp rising or falling, such as
roughness in the heddles or reed, or lumps on the yarn, it will not,
unless very tight, fall into its proper place, and the shuttle may pass
over or under it when it should not do so, giving a picked or darned
effect to the cloth; slack threads may cause the same.
The warp must be kept as tight as possible, and all the threads should
be at a uniform tension, the heddles straining each thread alike; the
harness should be as close to the heddles as the yarn will permit it
to be. The space occupied by the harness, heddles, and traverse of
lay should be no greater than is necessary; then, with a small but
clear shed satisfactory work can be produced. When drawing a warp
into the harness, a boy or girl sits behind, and hands the threads to
the drawer-in, who takes them into the mails with a wire hook, and
then either hands them to a second drawer-in sitting in front of the
heddles, to be drawn into them, or passes them over and under a pair of
rods tied across the harness so as to form a lease as she draws them
in; and when she has all drawn into the harness, she begins to draw
them into the heddles, a straight draught being mostly used for a twill
or satin.
[Illustration: Fig. 112]
The front mounting of a damask hand loom is shown in Fig. 112. A, A
are the shafts, four in number, but eight are generally used for an
8-leaf satin; B, B are the jacks; C the lams, which require to be one
more in number than the leaves of heddles; D the treadles; E, E^1 the
upper marches or jacks; F, F^1 two sets of coupers or levers, with
their fulcrums at _f_, and loaded at the outer ends with the weights G.
Under the ends of these levers is a bar N, to which the weights draw
them, and keep the heddles up to their middle position. The cords I are
not fastened to the heddles, but pass down through them to the lams
C. The cords L connect the coupers with the heddle shafts. Each lam
has two cords tied to it, except the two outer ones--_i.e._ the first
and last one--which together act as one, to avoid crossing the cords.
One of the cords I is tied to each lam, and also one from the jacks B;
but the first and last lams have only one cord tied to each of them,
one having the cord I, and the other that from B. Both these lams are
connected with one treadle, and the others are each connected with a
treadle. Of course, the cording is made in the usual way, agreeably to
the pattern, two methods of twilling being shown in Fig. 113. When the
weaver presses down a treadle, one leaf of heddles is raised by the
cord I connected from one of the levers E, E^1 to one of the marches
or lams C, and one leaf is at the same time sunk by the cord connected
from one of the jacks B to the lam connected to the treadle. The other
treadles act similarly when corded for a twill or satin.
[Illustration: Fig. 113]
The cording generally used for an 8-shaft satin is shown at A, Fig.
113. Sometimes the twill is run in the reverse direction. In either
case it will be observed that the twill on both ground and figure run
in the same direction, which makes one a sateen, or coarse twill, and
the other a satin, or fine twill. In order to have both twills alike
they require to be run in the opposite direction on the cloth, as shown
at B, which will give a fine twill on both ground and figure, on both
sides of the cloth, with single yarn. This does not hold good with
every twill. When weaving, the weaver presses down the treadle which is
connected with the jacquard (another treadle being required for this
purpose) with his left foot, then works over the twilling treadles with
his right foot, holding down the machine treadle till he gives as many
shots to the cards as are required. When the card is to be changed the
weaver lets down the machine and draws another shed, striking up the
weft again without throwing in a shot or taking his right foot off the
treadle. This clears up the shed, and makes the yarn steady before he
springs another shed with the presser leaves, giving a regularity and
firmness to the work which it is impossible to get otherwise, but which
has to be done without in the power loom. The weft is struck up on the
open shot, or before the heddles have closed the shed. Sometimes a sort
of dobby is used below the lams, which enables the weaver to work the
heddles with one treadle. In power looms a similar principle of front
mounting is sometimes adopted, substituting a wyper tappet for the
weaver’s foot; but a better plan, as it avoids having the cords passing
through the yarn and heddles, is to have a box tappet, on the Woodcroft
style, made with solid plates, and struck to give the rising and
falling motion. The connections from the tappet to the heddle shafts
are made in the same way as the ordinary Woodcroft tappet. The jacquard
may either be a single or double-lift one. Some prefer the one, some
the other. The single-lift is more easily fitted up, especially if
the number of shots to the card varies. When the shots on each card
are alike, perhaps the steadiest method of lifting the machine is to
have a box tappet struck one up and three down, or one up and two
down, according to the number of shots on the card. This tappet acts
on a bowl on a treadle, to which the rod for raising the machine is
connected. For a double-acting machine there must be two treadles and
tappets acting alternately. The cylinder can be driven from the rising
and falling of the machine with a swan-neck or lever motion, or may be
driven from an eccentric on the loom with a pinion on the crank shaft
turning it one to three or four shots, as may be desired. When the
shotting to the card is irregular there are several methods adopted for
lifting the machine griffes, one of the best of which is shown in Fig.
114 for a single-lift machine.
A is the treadle to which the connecting-rod from the machine is
fastened by a bolt through the slot at H, or the slot may be in any
desirable place. B is a rack in which the end of the lever works, which
keeps the treadle bowl steady to the tappet. E is the tappet on the
tappet shaft of the loom, and is made so as to act at every shot. D
is the fulcrum of the lever, and C is the stand, which is bolted to
the ground and fastened to the side of the loom. This portion of the
motion working alone would raise the griffe for every shot, the same
as would be required for a full-harness, single-acting jacquard; but
when the griffe is raised by the tappet E, it can be held up as long as
is desired by letting the bell-crank catch F fall in over it as shown.
When the treadle A is in this position the tappet merely touches the
bowl, depressing it about 1/8 in., so as to clear it off the catch;
this is to allow the catch to be easily pushed off when it is required
to let the treadle up, or to drop the griffe. The catch is moved by the
cam or tappet G acting on the bell-crank F. This tappet can be driven
by a pinion on the crank shaft or by a catch on the slay. It may be a
tappet struck to suit, or a barrel with a set of lags or pins on it, so
that the machine griffe may be raised and lowered in any order that is
desired.
[Illustration: Fig. 114]
An ingenious method of working the heddles of a pressure harness by the
jacquard was invented in Bethnal Green shortly after the introduction
of the original machine. It was used for weaving the richest silk
damask, which had 400 threads of warp per inch and about one-fifth
that number of weft shots, so that five threads of warp might be drawn
into each mail without making the pattern appear any coarser in the
warp than in the weft. A sketch of this mounting is given in Fig 115.
A shows the hooks for working the heddles, and B those for working the
harness. Eight hooks are given for working four leaves of heddles. It
will be seen that a cord from two hooks passes round one of the pulleys
C, and each of the heddle shafts is attached to one of these pulleys.
These hooks may be raised by the griffe of the jacquard, which would
require to rise and fall for every shot, or the griffe may be held
up for the number of shots to the card, and the hooks for working the
shafts may be wrought by a small dobby. When one of each pair of the
hooks A is raised, the heddle shaft connected with it is raised to
the middle position, as shown by the pulleys 1 and 2, and the leaves
connected with them. If neither of the hooks is raised for any shaft,
it will remain sunk, as shown in No. 3; and if both the hooks are
raised, the leaf will be raised to its top position, as No. 4. The
leaves are drawn down by weights or springs.
[Illustration: Fig. 115]
TWILLING JACQUARDS
[Illustration: Fig. 116]
As has been stated before, one of the drawbacks to a pressure harness
is the strain which the warp has to undergo when forming the shed. This
necessitates having a good warp, which adds to the cost of the cloth,
and in low-class goods this consideration may hinder the sale. Many
methods have been adopted for working the ground of the cloth without
using a pressure mounting. Some of these are explained under ‘half
harness’ and ‘split harness,’ but none of these methods would produce
cloth like the pressure harness. A twilling jacquard to act similar
to the pressure harness, but without using the front mounting, or by
dispensing with the leaves of heddles, was patented by Mr. Shields,
of Perth, in 1859. This machine underwent several improvements, and
now there are two varieties of it in use, one known as the Irish or
Bessbrook machine, being patented by Mr. Barcroft, of the Bessbrook
Spinning Company Limited, county Armagh; the other as the Scotch
machine, the improvements being made by Mr. Shields and others. The
principal difference between the two machines is that the blades or
knives of the griffe have a horizontal or sliding motion in the Scotch
machine to enable them to get clear of the heads of the hooks, whereas
in the Bessbrook machine they turn out of the way or partly revolve.
A full description of the Bessbrook machine is here given. Fig. 116
is a view of the framing of the machine. K is the cylinder, which may
be wrought by the swan-neck motion, as shown, but it is better to be
wrought by a separate motion from the loom. D is a cord attached to
the handle of the shears for reversing the cylinder; E is a brass
bushing through which a shaft passes for raising the griffe. The
shedding of this machine is exactly the same as that of an ordinary
single-acting jacquard. The griffe rises and falls for every shot;
the cylinder travels out and in, but does not turn till two or three
or whatever number of impressions required are given by each card. To
prevent the cylinder turning it is only necessary to raise the shears
so that they will not catch it. This is done by means of the tappet A,
shown in Figs. 116 and 117. The roller H on the shears rests on the
tappet, which is turned by means of the rack wheel, which is fast on
it, and the lever L, which is loose on the stud. This lever is pushed
backwards and drawn forwards by the rod I, which is connected to an
arm, either on the shaft for raising the griffe, or on one for working
the cylinder, and the catch on the lever takes a tooth of the ratchet
wheel at each draw, so that with four divisions on the tappet, and 12
teeth in the ratchet, three shots would be given to each card. If it is
required to work the cylinder the reverse way, it is only necessary to
tie the cord D on the end of the shears to a spiral spring made fast to
any convenient part of the loom, then the roller C will be acted upon
by the underside of the tappet, and the under hook of the shears will
turn the cylinder when required. B is a spring acting as a pawl to keep
the ratchet from moving backwards, and there is also a spring shown
over the catch which moves it forward; both these springs serve to keep
the tappet steady. There are two sets of hooks and needles in this
machine--the ordinary set for working the harness, as shown at A (Fig.
118), and a set of twilling hooks, one row at each side of the machine,
which are much stronger than the others. The ends of the twilling hooks
are hooked round bars, which pass through the loops at the lower ends
of the ordinary hooks, as shown at C (Fig. 118). These bars are kept in
their places by a grid D, which is between the ordinary hooks and the
twilling hooks. Each of the needles of the jacquard is connected with
two or more of the ordinary hooks, as shown at A. The twilling hooks
have also needles on them, but they are only for the purpose of keeping
them in their places, and are not acted upon by the cards. The springs
of these needles are on the ends next the cards, or at the back of the
faceplate or needle, as shown at E. The centre support for the knives
of the griffe is shown at F, with an end view of two knives G G. The
ends of the knives enter the griffe frame at each side, so as to allow
them to oscillate or partly revolve. This motion is given to them by a
set of bars or flat needles, as shown at A (Fig. 119). A single needle
is given at A^1. These needles have each the notch in them over the
top edge of two or more of the knives, and are acted upon by a barrel
C with studs in it, set to the twill. This barrel rises and falls with
the griffe, and is turned from one row of pegs or studs to the next one
each time the griffe falls by the head or lantern on it coming down on
a finger, as shown at A (Fig 120). B in the same figure is a strong
spring to keep the barrel steady and make it turn the correct distance.
[Illustration: Fig. 117]
The number of knives in the griffe must be regulated to suit the twill
to be put on the cloth; they must be a multiple of the twill, and this
to some extent regulates the number of needles that must be in each
upright row. For example, an 8-leaf twill may have 16 or 24 knives,
which would be twice or three times over the twill. If there are 8 rows
of needles to 16 knives, or 16 rows of hooks, that would be 2 hooks to
each needle, or if there are 24 rows of hooks there must be 3 hooks to
the needle; but if only 2 hooks to the needle are required, there must
be 12 rows of needles to 24 rows of hooks. The same principle holds
good for a 5-leaf, or any twill. Eight or 12 rows of needles would
not be suitable for a 5-leaf twill, neither would 10 rows of needles
be suitable for an 8-leaf twill, if the same number of hooks have to
be connected with each needle; but 10 rows of needles with 20 rows of
hooks or 20 knives will answer for a 5-leaf twill with 2 hooks to the
needle, or would answer for an 8-leaf twill with 24 rows of hooks, 4 of
the needles to have 3 hooks to each, and 6 of them to have 2 hooks to
each.
[Illustration: Fig. 118]
Each of the twilling needles, A, Fig. 119, must be connected with as
many of the knives as there are repeats of the twill; thus, for 24 with
an 8-leaf twill, the 1st, 9th, and 17th knives would be acted upon by
the one needle, and so on with the others.
Now as to the action of the machine. When the pattern card presses upon
the needles the griffe begins to rise, and when rising it must lift all
the hooks required for the pattern except 1/8th part of them which
must be left down (in an 8-leaf twill) to form the binding or texture
of the cloth. In addition to this, 1/8th part of the ground warp must
be raised for the weft to pass under it and form the ground texture.
This is all accomplished by the one rising of the griffe. When the
griffe is down, one of the twilling needles, A, Fig. 119, is pressed
back by a peg or stud in the barrel, which causes the knives connected
with this needle to turn out of the way of the heads of the hooks, so
that when the griffe is rising these knives will pass clear of them,
leaving every eighth row of hooks down to form the binding of the
raised or pattern warp. In the Scotch machines the knives slide back
instead of revolving. As shown at H, Fig. 118, there are projecting
pieces of brass fastened on the knives between the twilling hooks.
These hooks stand clear of the knives, but when the latter revolve the
projections on them push the hooks forward to the next knife, which
lifts them when the griffe is rising. The hooks draw up the bars to
which their lower ends are looped, and raise the rows of ordinary
hooks through which the bars pass, thus forming the twill on the ground
in the same way, but in the reverse direction, that the knives passing
clear of the adjoining rows of hooks form the twill on the figure.
[Illustration: Fig. 119]
[Illustration: Fig. 120]
The working of the texture requires the griffe to fall for every shot,
which would be otherwise unnecessary, and the card must come in against
the needles each time to push off the hooks that are not to be raised.
This causes wear and tear, which cannot be avoided with this machine,
but they work very well, though they are not by any means perfect.
There is a good deal of friction on the needles, which causes them to
wear quickly; but being so much easier on the warp than the pressure
harness, and more easily managed, they are extensively used for large
patterns in the fine linen damask trade. They will not make so firm a
cloth as the pressure harness, and have the objection that all twills
formed with the harness have when there is a gathered tie--viz. that a
portion of the cloth will have the twill running in one direction and a
portion in the reverse direction.
Like all single-acting jacquards, these machines have no counterpoise
in themselves, and being very heavy require one added to assist the
loom to raise them. Sometimes this is accomplished by means of a
carriage spring placed on a beam or on the top rail of the loom frame;
and an arm from the shaft, which raises the griffe resting on the
spring, will form a sufficient counterpoise, the spring being made
as strong as is required for the purpose. Unless the springs, which
are made similar to those used for carriages, are nicely tempered,
and the different pieces made so as to slide freely on each other,
they are liable to snap when the loom is running quickly. The griffe
is generally driven from the fly-wheel on the crankshaft in the same
manner as for ordinary single-acting jacquards. It is, however, a
better plan to drive it from a crank on a stud wheel gearing into
the tappet-shaft wheel. This does away with the necessity for a
counterpoise unless the machinery is very heavy, in which case a
few strong spiral springs will suffice. The horizontal shaft for
raising the griffe, or griffes if two or more machines are used, must
be very strong, so as not to twist with the tortuous strain, which
is very great. Three of these machines, with 500 or 600 needles to
each, are required for tablecloth mountings when tied up for centred
patterns--one machine to work the border, one the centre, and one the
portion between the border and the centre; or two machines to work the
double portion, and one the single portion. Fig. 121 gives a view of
a mounting tied up in this way, Nos. 1 and 2 machines being double
mounting and No. 3 single.
[Illustration: Fig. 121]
_The Karl Wein Jacquard._--This machine is a twilling jacquard on the
same principle as that last described, but performs its work in a more
scientific manner. It was patented by Messrs. J. Tschörner and K. Wein,
Kesmark, Hungary, and was first introduced into this country at the
Glasgow Exhibition of 1888.
The following is a description of the machine exhibited there: The
principal feature of this machine is perhaps that each knife acts
independently in a grid, and is wrought by a tappet at the side of the
loom, so that any row of hooks can be raised or lowered at pleasure,
and this without any change of card. Fig. 122 gives an end view of
the framing, showing the upper and lower grids in which the knives or
lifters slide. An end view of four of the lifters is given at A, 1 and
3 belonging to the top set, which work in the upper grid, and 2 and 4
to the bottom set, which work in the lower grid.
[Illustration: Fig. 122]
A perspective view of eight of these lifters is given at B C, Fig.
123, with upright slide bars D attached to them, which slide in the
rack or frame E. These bars are for the purpose of making the lifters
rise steadily and horizontally, as (which may be seen) they are not
all lifted at their centre. Only one connection is fair in the centre,
which would no doubt be an objection with a heavy harness to lift; but
this arrangement is made to suit for the machine sitting across the
loom, for a London tie, and some method of making vertical connections
from the levers to the lifters is necessary. The above does very well
for a narrow harness if light.
[Illustration: Fig. 123]
[Illustration: Fig. 124]
If the machine was fixed on the loom for a Norwich tie, or with the
cards to hang over the back, then the connections from the levers might
all be at the centres of the lifters and the bars D would only be
required to steady them. The levers for raising the lifters are shown
at F, with their fulcrum at I. G is a spring, one of which is attached
to each lever to keep it down, as the tappet has not a positive
rising and sinking motion, only raising the levers and allowing their
own weight and the draw of the springs to recover them. One of the
connecting rods from the lever to the tappet is shown at I. Fig. 124
gives the principle of this tappet. A is the lever or treadle with
its fulcrum at A; the connecting rod B connects the point of it to
one of the top levers F (Fig. 123), and C is a bowl at the other end
of it which travels on the tappet plate D. The tappet is made up of
17 plates struck to suit; 16 of these are for working the lifters and
1 for the cylinder; it sits at the side of the loom like a Woodcroft
tappet. For an 8-end satin twill 16 levers are required, 8 for the
bottom set of lifters and 8 for the top set. Fig. 123A shows two
lifters B^1 and C^1 with hooks and needles. A hook and a needle on a
larger scale are shown in Fig. 125. The hooks are flat pieces of iron
cut to the shape shown, with small projecting pieces, as _a_, riveted
to them, by which they can rest on the bottom lifting knives, as at
C^1 (Fig. 123A), so that when any of these knives are lifted a row of
hooks will be raised by them. As before explained in reference to the
Bessbrook machine, it is necessary when the pattern card presses on the
needles for all the knives except one to act, and also for one of the
bottom lifters to rise to form the texture of the cloth; the same must
be in this machine, and can easily be regulated by the tappet, which
should hold up the warp required for the pattern and work the ground
texture as well. This is done in the following manner: Suppose there
are 16 lifters, 8 top and 8 bottom ones. When the card presses on the
needles, 7 of the top and 1 of the bottom lifters should be raised by
the tappet, and the top lifter, which is left down, should be raised
so far as to catch the heads of those hooks in the row belonging to it
that are not pushed back by the card. For the next shot this lifter is
raised and another one let down, but it is not let down far enough for
the hooks to get off it, stopping at the same height that the first
one was raised to, which is easily regulated by the tappet. If there
are 3 shots to the card, another similar change takes place; then for
the fourth shot all the lifters are dropped, the cylinder presses
in, and all but one of the top lifters and one of the lower ones are
again raised, and the twill proceeded with as before. It will thus
be seen that the shedding for the twill acts as in a double-acting
jacquard, but the lift at the change of card is similar to that of a
single-acting jacquard. Of course the tappet must be struck to change
the lifters according to the twill required on the cloth. In the
Bessbrook machine there could be 16, 24, or 32 rows of hooks to 8 rows
of needles by having 2, 3, or 4 hooks to each needle, or the number
of hooks to each needle might vary and any number of needles might be
used. There must be a knife for each row of hooks, but all the knives
belong to the one griffe. In the Karl Wein machine there must be 2
lifters for each row of hooks, and 16 of them are enough to have for
convenience. In the machine exhibited, 16 hooks, or 2 rows of 8, were
attached to 6 needles, 4 needles having 3 hooks to each and 2 needles
2 hooks to each, as shown at B (Fig. 125), the thick vertical lines
representing 1 row of hooks, and the thin lines the next row. There
were 6 rows of needles in the needle board, and the point of each
needle was cranked as shown at C; each row of holes for the needles in
the needle board, or face-plate, stood between 2 rows of hooks: the
first 3 needles were connected with 1 row of hooks and the second 3
with the next row, the cranks of the first and second set of needles
being turned in the opposite direction so as to enable them to fall in
with the rows of hooks. Of course there might as well have been 8 rows
of needles with 2 hooks to each, or 4 needles to each row of hooks.
[Illustration: Fig. 125]
If necessary to use more than one machine, some arrangement would
require to be made for lifting them. It might be done by using a double
set of levers with connecting rods similar to those used for twilling
looms.
The twilling of the ground might be wrought by a griffe and hooks as
in the Bessbrook machine, thus doing away with seven treadles and
seven tappet plates, but this would make the twilling a single-acting
shedding motion.
Since this was written the machine has been altered so as to make it
more suitable to the requirements of the work in this country, but
does not appear to gain favour, and this class of weaving is not very
extensively used.