As is well known, in the process of bleaching and dyeing, cotton cloths
become considerably contracted in the width, in consequence of carrying
on the operations when the cloth is in the form of a rope. The effect is
that, together with the tension, although slight, and the drying, the
weft partly shrinks and partly curls up, the latter, however, being
scarcely observable to the naked eye. It may almost be said that as
regards the width the shrinkage is due to a number of minute crumples
because the cloth is easily streatched again by the fingers almost to
its gray width. The main use of a stretching machine, therefore, is not
so much to make the cloth more than it is as to bring it again to its
normal or woven width after operations that tend to shrinkage have been
performed upon it. The stretching operation, therefore, is especially
useful to calico printers, as it enables them to obtain when desired a
white margin of even width, the irregularities due to bleaching being
corrected before printing.
[Illustration: IMPROVED CLOTH STRETCHING MACHINE.]
The machine now illustrated is one we have recently seen in operation in
a Salford finishing works. It is an improved form of another stretching
machine which had been turned out in considerable numbers by Mr.
Archibald Edmeston, engineer, of Salford, who makes a specialty of
calico printers' and finishers' machinery. The improvements consist
mainly of a simplification of the working parts and thoroughly
substantial construction of the machine. The principle adopted is a
well-known one. The selvages of the cloth, or more strictly the two
edges of the cloth, of a width of about two inches, are caused to pass
over and at the same time are held by the rims of two diverging pulleys.
The rims are further apart where the cloth leaves them than where they
seize it, hence the stretching is gradually, certainly, and uniformly
performed. The cloth is gripped by the pressure of an endless belt
acting against the lower half of each pulley, the edges being held
between them. In the engraving these stretching pulleys are indicated by
the letters AA; the endless leather band passes over the pulleys, CC, of
which there are a set of four provided for each stretching pulley. The
lower pair of pulleys in each case may be tightened up by a screw
for the purpose of imparting the requisite tension to the bands. The
stretching pulleys are mounted upon and driven by the same shaft, an
ingenious but simple swiveling joint in their bosses enabling them to
be set at any angle to the shaft and yet to revolve and be driven by it
without throwing any undue strain upon the working parts. The piece,
wound upon the ordinary batch shell, is placed upon the running-off
center, D; it is led off over the rails, EE, and then downward to the
nip of the bands and pulleys, AA. As explained, the selvages are here
gripped between the bands and stretching pulleys, the rims of which are
wider apart at the back than the front, and thus, in being conveyed
underneath, the piece is suitably stretched. Leaving the grip at the
back it passes over leading-off rollers, FF, and the scrimp or opening
rail, G, and thence downward to the winding-on center, which cannot be
seen. The winding-on center is driven by friction. As the batch fills
it and tends to wind faster than the machine delivers the cloth, the
driving slips. In addition to a capability of being set at an angle to
the shaft, the stretching pulleys, AA, may be slided upon, so as to
separate or bring them closer together, to allow for the treatment of
different widths of cloths. This adjustment is provided for by mounting
the stretching pulleys, AA, and the band pulleys, CC, etc., on frames,
BB, the ends of which rest, as shown, upon rails, at the back and front
of the machine. The adjustment either for width of piece or for the
angularity (extent of stretching) is easily made by the hand-wheel, L.
By the bevel wheels shown, two cross screws having nuts connected to the
ends of frames, BB, are actuated in such a way that as desired the space
between the back and front of the pulleys may be closed in or opened
out, or the two wheels, maintaining the same angularity, may be
separated or closed in, either adjustment being expeditiously made. The
wheels, HHH, are called center stretching wheels, the use of which is
sometimes advantageous. They act in conjunction with a set of stretching
pulleys, of which one, K, may be seen in illustration. By a proper
adjustment at the latter the piece is bent into a wavy form, where it
passes between the whole of them, the effect of the corrugation being
to loosen the center threads and to allow the piece to be more equally
stretched with those near the selvages and more easily. This part of the
machine may be used or not as required. The production, we observe, was
about 120 yards per minute. The machine is solidly built and well fitted
together, as was obvious to us from an inspection of some in course
of construction at the maker's works. It is also claimed to be of
considerable advantage to bleachers and finishers of white goods,
on account of the uniformity of the stretching causing but small
disturbance to the stiffening.--_Textile Manufacturer_.
* * * * *