DROP-BOX LOOMS, STRIPES, CHECKS, AND SPOTTING.
In certain classes of cotton fabrics stripes are a leading feature of
the cloth, and are made either in colour or in different counts of
yarn, or reed or pick; stripes may run length-way of the face as in
dhooties, sarongs, some shirtings, regettas, tape muslin, ticks, and
many other cloths, and in these cases the effect is produced simply by
warping and reeding the ends in the required order, often by varying
the number of ends in different dents.
STRIPES
May run transversely, and are then formed by coloured or vari-counted
yarns, or a series of spots in colour may be shown on the face of the
cloth, a stripe of extra weft being shown at the back of the cloth and
brought through to the face as required. In these cases some system
of manipulating extra shuttles carrying the different wefts must be
adopted.
CHECKS.
The third class with which this chapter more especially deals is the
checked cloth--ginghams, Oxford and Harvard shirtings, tape checks,
satin checks, etc. These are all formed by combining warp stripes with
weft stripes of corresponding colour and extent, thus forming squares
of colour on the fabric. These patterns may be formed in endless
variety of colour, weave, or length.
In ginghams, the colours used are often four or five in number--say
20 pink ends, 2 black, 6 white, 2 black, 6 white, 6 black, 6 white, 2
black, 6 white, 2 black = 58 ends in the warp pattern, while the picks
of weft are in the same colours, number, and order. In the larger
patterns the number of ends and picks may get into the hundreds. Fine
counts are often used.
In shirtings of heavy material for the home cotton and union material
trade, smaller patterns are commoner, as they are also in all the
“zephyr” class of goods--such, for instance, as shirting, warping 12
white 24’s, 2 red 20’s, 12 white 24’s, 2 blue 20’s; weft same; weave,
4-end cashmere twill.
In white yarns, satin checks may be made with satin stripes on a plain
ground, the satin ends being “cramped” in the reed, and the picks being
inserted in other yarn of special spinning.
Tape checks are similar, excepting that the weave is plain all through.
These one-colour checks must not be confused with the crossovers and
the satin or other checks formed by the same weft, but heavier in pick
at places.
Handkerchiefs in colour have the appearance of a large check, but
when the coloured headings are far removed it is advisable to change
shuttles by hand, as the chain for the drop box would be too long. Some
check looms, however, carry contrivances for stopping the motion of the
chain when the body of the handkerchief, shawl, towel, etc., is being
woven, this being a very suitable system. In case of changing by hand a
measuring motion is attached to the take-up roller to stop the loom at
the place for heading.
THE DROP-BOX LOOM.
For changing the shuttle a drop-box loom is generally employed. In
a double drop-box machine six boxes may be used at each side of the
loom, any one of which may be brought into action, giving a scope of
eleven colours of weft. The single drop box is, however, more usually
employed, with four or six boxes at one side of the loom, only giving
four or six colours, but not allowing less than two picks of the same
colour to be put in. To insert single picks of colour a double-box loom
is used, and possesses a special pick-and-pick arrangement (uncommon
in the cotton trade) to admit of its picking twice consecutively from
either side of the loom. The number of boxes just mentioned is seldom
met with in the cotton trade, three and four boxes being the usual
sizes. The single four-shuttle drop box carries a frame at one end
of the slay in which the boxes or shelves rise or fall. These boxes
contain the shuttles, and by suitable regulating motions the boxes may
be shifted so as to bring any one shuttle level with the shuttle race
and in front of the picker. The spindle is duplicated, and the couple
is placed in front of the box, not above, as in a plain over-pick loom.
The picker is broad and is without nib, fixed in a horizontal position,
so as to act on any one of the shuttles which may be placed before it.
The principal drop-box regulating motions are Diggle’s chain and Wright
Shaw’s motion.
DIGGLE’S CHAIN MOTION.
Diggle’s chain is noted for short patterns, is simple in construction,
and sure in its action. Attached to the loom top is a star wheel A
and barrel B revolving on a stud. The barrel carries a chain C, of
different sizes of links united by pins; the star wheel receives its
motion through a train of wheels from the crank-shaft, of which D and
E are connections. The links of the chain support a lever F, connected
with another lever G at the loom side supporting the drop boxes. For a
four-shuttle box the links are of four heights, the deepest raising the
boxes to the highest point, while the lowest link supports the levers
so that the boxes are at the bottom, with the top shuttle level with
the shuttle race. The chain is arranged so that a sufficient number of
links of the same height are placed together where several picks of the
same colour are required. The shapes of the links are varied to adapt
the lifts from or sinking to different boxes--thus, for a four-box
loom twenty different shapes of links may be used to give lifts or
depressions from any box of the four to any other; their arrangement in
chain depends on the before-mentioned principle. A plate of links is
shown at Fig. 72. They will be seen to be of four different heights. A
44-inch loom of this make may run 150 picks per minute. The change of
shuttle is made immediately the shuttle enters the box. We are not able
to change the shuttle at less intervals than two picks, but can do so
at greater intervals--say, for example, once in four picks.
[Illustration: FIG. 71.]
[Illustration: FIG. 72.]
WRIGHT SHAW MOTION.
The motion called, after its inventor, the Wright Shaw motion is
perhaps more suitable to cotton goods. Indeed, in Manchester, near to
which city it was invented and is manufactured, it finds much favour in
the check trade. A greatly improved motion has been recently introduced
by Mr. Wright Shaw, but as the older form is in commoner use, we will
refer to the latter.
[Illustration: FIG. 73.]
Fig. 73 shows a sketch of this machine, in which the parts will be
clearly seen. It is the make of Messrs. Henry Livesey, Limited, of
Blackburn, but is on the Wright Shaw principle improved. The shuttle
box is supported and moved by a rack and pinion; this pinion shaft
is actuated by a forked rack supported on a pivot at the end of a
lever, so as to gear with either side of another wheel on the pinion
shaft. The lever is driven by a cam, and raises and lowers the fork.
The pattern chain consists of iron plates which are thin and narrow,
thus enabling a longer pattern to be obtained than is possible by
the previously described motion. These plates are linked together by
elastic bands, and each contains two peg holes, and also one, two, or
three larger holes to correspond with the points of the three-pattern
chain needles. The pattern chain passes round a square block perforated
to correspond with the needles, and driven at the speed of a quarter
of a revolution for each two picks. The pegs on it carry the pattern
plates round with the block. The needles are arranged horizontally,
points facing pattern block. The outer needles regulate whether the
right or left leg of the fork shall be in contact with the wheel on
pinion shaft, to determine whether the reciprocation shall be upwards
or downwards. A hole in either one side or the other of the plate
regulates this; should both sides be perforated, the fork remains in
its previous position. The fork is raised and depressed by a lever,
actuated by one of two cams--one to move the boxes one shelf, and
the other to skip a shelf, thus moving two boxes. These cams are
changeable, and operate on one end of the lever, while the fork is
suspended to the other end. The central needle decides which shall be
in action, as it carries a projection which, when pushed back, thrusts
the larger sweep cam into action. It is easy, therefore, to understand
the action of these cards; three holes give no movement; two holes,
with a blank at one side, put the fork into gear with the corresponding
side of the pinion wheel; and in the case of two blanks, the one in the
centre puts two-box stroke in action, and the side blank puts the fork
in gear at one side. One blank at the right side causes a rise, or, at
the left side, a fall. The five forms of plate are:--
[Illustration: No change. Rise one. Fall one. Rise two. Fall two.]
Rising one means that the box is risen to the next shelf; rising two
is risen to the next shelf but one, skipping one. This style of drop
box can be driven at the speed of 170 picks per minute. Generally, a
weaver attends to three of these looms, and an overlooker to from 50 to
60. For the check shirting trade looms to weave from 30-inch to 37-inch
cloth are used.
OTHER MOTIONS.
An ingenious drop-box motion is manufactured by a Burnley firm, by
which the weight of supporting the boxes, etc., is altogether removed
from the pattern chain, which is consequently made of less cumbrous
construction. Other firms claim decided advantages in respect of a
greater skip than either Diggle’s or Wright Shaw’s motions--_e.g._,
from the first to the sixth box. Skips of this extent are obtained
principally by using several eccentric cams. One of these may lift a
single box, a second may raise the boxes two spaces, and their effect
in combination is a lift of three shuttles, and so on for greater
effects.
CIRCULAR BOXES.
Circular boxes are seldom used for cotton goods. In this arrangement
the shuttles are fixed in grooves formed in a block revolving at the
slay end, and drawn round in either direction by hooks, one being
placed at each side of the revolving barrel. The movement of the hooks
is regulated by a pattern chain. The speed is about the same as a
Wright Shaw motion.
GENERAL.
Any of these types of boxes may be used with the over-pick, and either
with tappets, dobby, or jacquard shedding. Attempts have recently been
made to apply the drop-box principle to a system of replenishing the
loom with three or four cops of weft without a stoppage, by having
them previously placed in the shelves and lowered on the breakage or
running-off of the previous weft.
COLOURED SPOTS.
Additional colour is introduced into cotton fabrics in spots and
figures after the manner of embroidery, by using circle swivels or
lappets. If a series of small spots in colour are required to be made,
by using a drop-box loom with a jacquard or dobby the object is easily
attained, but it necessitates the cutting away of much of the coloured
yarn which has been picked across the cloth, and only a portion of
which is required for the figure. Now, by using extra twist or weft,
and only interweaving as much as is required for the figure alone, much
waste can be prevented, and a firmer spot obtained. Take, for example,
the spotted muslin so frequently used for window curtains; each figure
only consists of a few inches of coarse yarn so loosely passed through
the ground cloth, and apparently so entirely independent of the other
spots, that a tyro can form no other explanation of their appearance
there than that they have been sewn on.
CIRCLE WEAVING.
Circle weaving has been used in these cases. In addition to the ground
weft, which is carried across the cloth in the ordinary shuttle, there
is a frame above the shed of the warp carrying several circular, or
rather horseshoe-shaped attachments with a small bobbin of weft pivoted
at the upper part (farthest from the opening in the ring). These rings
are driven round by gearing with a rack. When the figure has to be
formed by the weft passing round, say 20 ends, these are raised above
the level of the top of the ordinary shed, inside the ring, which then
makes one complete revolution, and the ends are depressed. Maybe a
plain pick or two is then inserted, and afterwards more spotting, until
the desired figure is embroidered on the muslin, when plain weaving is
resumed for a few inches.
LAPPETS.
In lappet weaving, extra bobbins of warp are placed below the loom,
and the ends from them carried to a set of upright needles, which
slide in a groove immediately in front of the end, a false reed being
arranged for the guidance of the shuttle. The needles are regulated
by a cam, and, with their point projecting, raise the thread into the
shed, so that it may be bound into the cloth by the weft; after which
the needles are removed the distance of a few threads, and again raise
the coloured end, so that it may be bound into the cloth. The cam
causes the needles to be slid to and fro in this manner until a figure
is formed as desired. By this latter method the colour in the figure
largely predominates on one side of the cloth, that which is the under
side in the loom. The upper side merely shows the outline of the figure
where the thread has passed through to be bound. In the circle swivel
figures the weft usually shows equally on both sides.
[Illustration: Decoration]