Cops intended for use as weft are frequently dyed and bleached in that form, and woven without any operation of winding. If, however, weft yarn is dyed or bleached in hanks, it requires to be subsequently wound on to pirn bobbins or paper tubes to fit on a shuttle tongue. Weft is also sometimes woven in a damp condition, with a view to inserting a greater number of picks per inch in cloth than is possible with dry weft.
Winding Machines for Warp Yarn.
[Fig. 1] is a diagram showing parts of a “spindle” or “cop” winding machine, which is chiefly employed to wind grey yarn from cops, G, or ring bobbins on to warpers’ bobbins, E. It is also sometimes incidentally employed to wind coloured yarn from hanks, O (as represented on the left-hand side of the diagram), when the amount of work required of that kind would not justify the purchase of a “drum” winding machine, which latter is better adapted for that purpose, for reasons that will be explained later.
FIG. 1.
As usually made, a “cop” winding machine contains a tin driving drum, B, passing centrally down the machine, and carrying the driving pulleys at one end of the tin drum shaft A. By means of cotton bands, C, the tin drum drives four rows of spindles, D, arranged in two zigzag rows, one on each side of the machine, as shown in part plan (detached). Warpers’ bobbins, E, fit loosely upon the spindles, and rest upon metal discs, F, secured to the spindle-shanks, by which bobbins are frictionally rotated. During winding, yarn passes from cops, G, or other source, over a drag-board, H, through a brush, I, and clearer guide, J, thence over a glass rod, K, surmounted on guide-rails, and on to warpers’ bobbins, E. The drag-board H is covered with flannel to impart frictional resistance to yarn, and thereby prevent its passing too freely and making soft bobbins. The clearer guide (of which a front view is shown, detached) is a thin metal plate containing a number of vertical slits, L, from near the top of which are two short slits, M, branching upwards at an angle of about 45°. The vertical slits serve to guide threads to their respective bobbins, and also to remove any irregularities, as “slubbings” (i.e. thick, soft places consisting of a mass of untwisted fibres). The short slits are intended to prevent operatives from raising threads out of the guides, and so save themselves the trouble and loss of time involved in piecing up broken threads.
Spindle-shanks, D, are furnished with tightly-fitting grooved pulleys, N, termed “wharves,” around which driving bands pass. Wharves on each back row of spindles are usually made one-quarter of an inch larger in diameter than those of front spindles, to cause them to revolve at a slower velocity. The object of this is to enable some compensation to be made for the constantly accelerating pace at which yarn is wound, in consequence of the gradually increasing girth of bobbins by additional layers of yarn. When bobbins become about half full on front spindles, a winder removes them to back spindles to be filled.
If bobbins were allowed to fill on front spindles, the velocity at which yarn would travel towards the completion of winding would impart an abnormal degree of tension to it, and thereby make it more liable to break. It is in consequence of the excessive degree of friction to which yarn is subjected in a cop-winding machine that renders it unsuitable for winding yarn that has been previously dyed and sized.
FIG. 2.