Drawing. Thread Frame.
By the process of doubling and drawing, the cotton is formed into a loose porous cord, the fibres of which are arranged side by side. This cord is still too thick for yarn, but it cannot be reduced in size by drawing merely, for if this were attempted it would break; a slight twist is therefore given, which by condensing the fibres allows the drawing to proceed. This is the commencement of the spinning process (which is, in fact, little more than a combination of drawing and twisting) and is called roving.
Cotton Bobbins. Buffaloes with Bobbins. Roving.
The bobbin-and-fly frame is an exceedingly complicated machine, although the objects to be accomplished by it are sufficiently simple; namely, to give the roving a slight twist, and then to wind it on the bobbin. The first is easily done by the revolutions of the spindle; the second is more difficult. It is scarcely necessary to explain that the bobbins now under notice differ in no way from the reels in common use, except in being of very large size. The spindle which holds the bobbin is a round steel rod, driven by a small cog-wheel, fastened on the lower part of the spindle. The bobbin is slid upon the spindle, and the small bed or platform on which it rests is made to revolve by another series of small wheels. The spindle has two arms, called the fly or flyer. This fly is fixed on the top of the spindle in such a way that it can be taken off in an instant, for the purpose of putting on or taking off the bobbin. One arm of the fly is hollow, the other solid, and all this serves to balance the machinery. One machine contains from thirty to a hundred and twenty spindles, which, for economy of space, are placed in two rows, each spindle in the back row standing opposite the space left between two spindles of the front row. The action of the machine is this:—The sliver having been drawn by the rollers, is twisted by the rapid revolutions of the spindle into a soft cord or roving; this enters a hole in the top of the spindle, and passes down the hollow arm of the fly; it is then twisted round a steel finger, which winds it on the bobbin with a certain pressure.
Throstle. Flyer.
The throstle machine is usually made double, a row of bobbins, spindles, &c. occupying each side of the frame. The bobbins filled with rovings from the bobbin-and-fly frame, are mounted at the upper part of the frame in two ranges. The roving from each bobbin passes through three pairs of drawing rollers, where it is stretched out to the requisite fineness. On quitting the last pair of rollers, each thread is guided by a little ring or a notch of smooth glass, let into the frame, towards the spindles, which revolve with great rapidity, producing by the motion of their flyers through the air a low musical hum, which is supposed to have given the name of throstle to this machine. The roving, which may now be called yarn, passing through an eyelet formed at the end of one of the arms of the flyer, proceeds at once to other bobbins.
The yarn is wound upon the bobbins by a curious contrivance. The bobbin fits very loosely upon the spindle, and rests on its end upon a kind of platform. The bobbin is not connected with the spindle, except by the thread of yarn, which has to be wound; therefore, as soon as the flyer is set spinning, the thread drags the bobbin after it, and makes it follow the motion of the spindle and fly; but the weight of the bobbin, and its friction on the platform, which is promoted by covering the end with coarse cloth, causes it to hang back, and thus the double purpose is served, of keeping the thread stretched and winding it on the bobbin much more slowly than the flyer revolves. The yarn is equally distributed on the bobbin by a slow up-and-down movement of the platform.