_TERRY LOOMS--CARD CUTTING--LAPPETS_
[Illustration: FIG. 150.]
Terry looms are extensively used in the cotton trade, chiefly for
weaving towels, but often for striped dress and similar fabrics where
terry or loop pile is combined with other weaves. The loops can be
formed either on one side or both sides of the fabric, but the loop
formed in these looms is not to be compared with real loop pile woven
over wires, as the loops cannot be formed with the same regularity.
There are numerous terry motions, as they are called, most loom makers
having their own speciality. Fig. 150 is the design for a good terry
cloth. It will be noticed that the second and fourth ends are the
reverse of each other: one is up for four picks and down for one, and
the other is down for four picks and up for one, whilst the other two
ends are nearly plain. The first and third ends form the ground, and
the second and fourth ends the pile or loops. There are five picks to
the round.
[Illustration: FIG. 151.]
[Illustration: FIG. 152.]
The ground warp is on a separate beam to the pile warp, the latter
having a special tension to let off the required quantity to form the
pile. At the second pick in the pattern, just where the pile warp is
bound, the reed is made to beat further up than on the two preceding
picks, thus forming a pile by sending one half the pile ends to the
face and the other half to the back. The reed beats up to the front
for the second, third, and fourth picks in the pattern, as given at
Fig. 150, following which the reed is held back for two picks. Fig.
151 is a good motion for making the reed occupy the two positions when
beating up. P represents the slay, and a lever, A, centred at D, is so
constructed that when A is pulled down the reed is pushed forward. The
rod R is connected to a lever, M, on a shaft, N, placed under the loom.
A rocking motion is given to this shaft by a box cam, P, five to the
round (Fig. 152), so shaped as to lift and depress the lever QS for the
required number of picks. This cam is driven from the picking shaft.
By pulling the rod R downwards the reed is moved forwards, and the rod
will have to be kept down for three picks and moved up for two picks,
so as to keep the reed in its front position for three picks and a
little way back for two. The effect required is really to lengthen the
crank-arm at will, and the principle of the knuckle joint may be used
in its simplest form--that is, by having the crank-arm jointed in the
middle and fixed a little out of a straight line, and by straightening
the arm when the front position of the slay is required.
The real loop pile is woven over wires. The wires can be inserted and
pulled out automatically by a power-loom, but the richest kind of pile
is woven on the hand-loom. The structure of the fabric is shown at Fig.
153. The pile end is brought up over a wire every two picks, and when
the wire is pulled out the loops form a springy pile, which can be
made to give beautiful effects in dress goods. The principle is also
used in Brussels carpets, and similar goods. Where figured fabrics are
required on this principle, it is necessary to have each pile end on a
separate bobbin and weighted separately at the back of the loom, as the
take-up of each end would vary so much in the figure.
[Illustration: FIG. 153.]
[Illustration: FIG. 154.]
With cut pile the wires are either grooved, as at Fig. 154, or each
wire has a knife at the end, as at Fig. 155, and when the wire is
pulled out it cuts the pile. The best pile is formed by the grooved
wires, as the cutting wires are apt to drag the pile. When cut pile is
being made, about four or five wires are constantly in the cloth, for,
if the wire were pulled out immediately, the pile ends would fall away
from the cloth.
[Illustration: FIG. 155.]
[Illustration: FIG. 156.]
Looms are made to weave two pieces of plush (which is a long cut pile,
rather longer than velvet pile) in one loom simultaneously, one piece
above the other, after the manner shown at Fig. 156. The principle is
not used in cotton manufactures, although it has been tried. It is
chiefly used for silk plush.
CARD CUTTING.
[Illustration: FIG. 157.]
The cards are usually cut from the design on a machine called a
“piano” card-cutter. This machine consists of a punch-box (Fig. 157),
containing thirteen punches, twelve for cutting the smaller holes and
one for cutting the peg holes in the cards. There are eight “keys”
behind the punch-box, each of which has a small spring round it to
spring it back to its original position when the finger is taken off
it. These eight keys are used for cutting the eight rows of holes in a
400’s card, and for 600’s cards, with twelve rows of holes, the four
punches in front are used. The two punches in front at the right hand
are operated by the thumb on that hand, and the eleventh and twelfth
are operated by the thumb on the left hand. The eight keys behind are
governed by the four fingers on each hand. Fig. 158 shows the effect
of pushing in one of the keys. The key is pushed over the punch K, and
as an up-and-down motion is given to the whole punch-box by means of
two treadles operated by the card-cutter’s feet, the punches that are
locked will cut holes in the card. Where the keys are not pressed (see
Fig. 159) they do not act upon the punches, and the card is left blank
accordingly.
The card is clipped at the numbered end by a clip on the “carriage.”
This carriage recedes with the card for a space of one row of holes
every time the left treadle is pressed down. The method of cutting the
cards has already been explained with Figs. 108-110.
[Illustration: FIG. 158.]
[Illustration: FIG. 159.]
If several sets of cards of the same pattern are required, a repeating
machine is used. In the hand repeater the cards are made to leave
punches in a plate where there are holes in the card, and the plate
is then taken to a repeating press, where any number of cards can be
cut like the first by applying pressure to the plate, which is done by
passing it under a roller or wheel.
Some repeating machines are capable of repeating direct from one
set of cards to the other, at the rate of thirty or forty cards per
minute. The cards may be laced blank, and kept in stock ready for use
when required, which is a great advantage. The machine is built on
the Jacquard principle, and the punches required to cut are fastened,
whilst those which are not required to cut are taken out of the way of
the card.
These machines are rather costly, but in large fancy weaving
establishments they soon repay their cost.
LAPPETS.
[Illustration: FIG. 160.]
Lappet figures are formed by giving a horizontal motion to a thick end,
and making it interweave in the manner shown at Fig. 160. The system
has long been used in hand-looms, and it is now extensively used in
power-looms, especially in Scotland. The figures are usually produced
with a very thick end upon a fine muslin ground, and the advantage it
possesses over figuring with extra weft is that the figuring material
does not require cutting off every pick, and therefore there is not the
same amount of waste, and in addition the figures are more firmly bound
into the cloth.
Only small solid spot figures can be woven, as the figuring thread
cannot be bound between the extreme edges of the figure. This is the
chief disadvantage of the principle, and it is not to be compared with
swivels for the purpose of producing intricate designs. In swivel
weaving each figuring thread is placed in a small shuttle, which
receives a horizontal motion by means of a rack. The small shuttles
can be lifted out of, and dropped into, the warp, so as to allow the
figuring thread to be passed through the shed where the spot is formed,
and therefore twill or satin, and shaded effects, can be formed in the
spot. In lappet weaving the floats cannot be bound in the middle.
The chief advantage of lappet weaving is that it can easily and
satisfactorily be applied to a power-loom. Swivels have been applied
to power-looms, but not yet with entirely satisfactory results, taking
into consideration the question of cost.
The principle of the lappet power-loom will be understood from Fig.
161. In front of the slay cap the needle rack A is placed, the ends
resting in the slots BB, and this is moved downwards by the hook C
being lifted by the treadle F at the side of the loom. The figuring
threads are taken from a separate beam through the needles in the rack,
and it will thus be seen that when the rack is pulled down the figuring
threads will be at the bottom of the shed. When the treadle F is forced
down, the springs PP pull the rack back to its topmost position, and
when in this position the rack is pulled to the left by pressing down
the treadle D, the distance which the rack can be moved being regulated
by the size of the groove in the lappet wheel at that point.
[Illustration: FIG. 161.]
The lappet wheel G is a wheel with ratchet teeth, and is turned one
tooth at a time. The groove in the wheel is so shaped that the rack can
be pulled sideways a greater or a less distance as desired, to form a
spot or figure. The pin N fits in the groove, and when the treadle D is
pressed down the rack is pulled to the left as far as the groove will
allow, when the spring S gives way until the treadle reaches the bottom
of its stroke. When the treadle is released the spring K pulls back the
rack and treadle as far as the groove in the wheel will allow it. The
spring K is much weaker than S, so that when the treadle D is pressed
down the spring K gives way the first.
The needle rack being in front of the ordinary reed, a “false” reed
is required to guide the shuttle across the shed. This false reed M
is placed immediately behind the shuttle race, and it is lifted every
pick when the shuttle is going across, and dropped to make room for the
proper reed to beat up. The treadle E is used for operating the false
reed; the connection is shown in the diagram, and when the treadle is
pressed down the reed is lifted.
At Fig. 162 a section is given showing how the needle rack receives a
lateral as well as a perpendicular motion. The slay-cap is cut square,
and the cover C works loosely upon it. The needle rack A is pulled
down against the spring S, and the cover is pulled sideways by the bar
attached to the cover at O, carrying the needle rack along with it.
[Illustration: FIG. 162.]
[Illustration: FIG. 163.]
The treadles are operated by tappets, and those operating treadles E
and F must do so every pick, whilst the treadle D only requires to
be pressed down once every two picks, because the spring K pulls the
needle rack to the right. The tappets are shown at Fig. 163, where it
will be seen that when the treadle E is down, F is up, and the rack
will be dropped and the false reed lifted; and when the treadle F is
pressed down--letting the rack be pulled up by the springs, the treadle
D is pressed down, which pulls the rack to the left as far as the
groove in the wheel will allow it to move.
[Illustration: FIG. 164.]
[Illustration: FIG. 165.]
At the back of the lappet wheel a face cam L (Fig. 164) acts upon a
lever, MN, centred at P, and the bent arm of the lever N pushes the
hook C on to the treadle F when the spot figure is being formed, and
when there is no figuring going on the hook is pulled out of the way of
the treadle, and so the motion of the rack is stopped.
The pattern is formed by the groove in the lappet wheel (Fig. 165), and
in drawing this the wheel is divided into as many teeth as there are
picks in the pattern. The wheel is usually made of hard wood, and after
being smoothed off a number of circles are described, the distance
between each being equal to one dent in the reed. Suppose the pattern
is a continuous one, as at Fig. 166, the picks shown on paper being in
addition to the ground picks. In drawing a wheel for this pattern the
number of teeth required will be twenty-four, as there are this number
of picks in the pattern.
[Illustration: FIG. 166.]
The pattern extends to seven dents, and as the pin N (Fig. 165)
occupies four dents, it will be necessary to have eleven spaces, each
equal to a dent, in the groove. The first pick in the pattern floats
over two dents or four ends, and therefore the groove at this point
must be six spaces wide--four for the pin, and two for the space it
has to move through. Before the next movement of the rack, the wheel
will have been turned one tooth, and at this point the groove moves one
space further to the left. For the third pick both sides of the groove
are moved one space to the left, and the size of the float will remain
the same as in the second pick, but it will float over different ends.
The groove gradually gets wider until the tenth pick is reached, when
it narrows down again until it repeats on the twenty-fourth pick.
If there are two spots set “one and one” in the pattern, the wheel
requires one tooth more than the picks in a repeat, in consequence of
changing from one spot to the other.