Fig. 208.
(397) The procedure thus followed is that which is adopted in the case of yarns for export only. Where it is intended to twist them into thread a special machine is employed to wind the several strands together prior to doubling. Machines of this class are called “doubling winding” machines, and they enable a more perfect thread to be produced than is otherwise possible. When yarn is “doubled” by twisting together threads drawn singly from cops or bobbins placed in a creel, there are two chief evils existing. If one of the threads breaks, a certain length of the single thickness may be wound on the doubling bobbin, with the result that a faulty place in the finished article is found. There is, in addition, the difficulty that the broken thread may become wrapped round the top roller, producing a “roller lap,” which is so much waste. The production of “single” and of “roller laps” is undesirable, and should be avoided if possible. Further, if the two threads in passing through the feed rollers are not both at the same tension, one becomes loosely twisted round the other in a manner which is technically known as “corkscrewing,” as explained in paragraph 385. When thread is used for sewing machine, lace, or similar purposes, either of these faults is very objectionable. By using a machine in which the strands to be twisted are wound together before being so treated, and in which detector mechanism is employed, a finished thread is produced, which is generally quite free from the defects named.
Fig. 209.
(398) In Fig. [209] a perspective view of a doubling winding machine made by Mr. Joseph Stubbs, and in Fig. [210] a transverse section of the same machine, are given. Mounted on a shaft, extending longitudinally of the machine, is a series of drums A, which drive by frictional contact flanged bobbins B. The latter are held in the head of forked cradles C, and revolve freely upon a small spindle. The lower ends of C are subjected to the pull of weights J, connected with them by chains, as shown by the dotted lines. Coupled to the tail of the cradle C is a double frame E, which carries at its outer extremity a swinging or oscillating box or frame, in which are placed a series of small wires—known as detector wires—corresponding in number to the strands to be wound. The wires are formed at their upper ends G with a curl, and their lower ends F are straight. Immediately below the box a three winged wiper H revolves at a rapid rate. The operation of this mechanism is as follows. The cops to be wound have skewers thrust into them, which fit in adjustable cast iron brackets fixed on a longitudinal rod in the bracket O, fastened to the “bottom box.” In the case of bobbins, special provision is made for holding them. In any case, the yarn is drawn upwards through a guide plate fixed as shown, over a flannel-covered curved rail Y, the friction of which is sufficient to ensure a sufficient tension being put upon the yarn. Each “end” is then taken through one of the detector eyes G and upwards over a light roller X, then through a guide wire W, secured to the rod or rail Z. To the latter a reciprocal lateral motion is given, corresponding in length to the length of the bobbin between the flanges—in other words, to its “lift.” After passing the guide wire W the yarn is taken to the bobbins B, and as the two bobbins are by reason of their position on each side of the drum A driven in opposite directions, the yarn is taken on to them at different sides of the centre of the bobbin barrel. So long as the “ends” are being wound, the lower end F of the detector wire is kept out of the path of the wiper H, but when, from the failure, breakage, or slack tension of an “end,” this sustaining power is withdrawn, the end F of the wire affected comes in the path of H. This causes the oscillating box to swing on its centres, and thus to release the holding down catch I, which usually keeps the pivoted frame E pressed downwards. This release is followed by a certain movement of the cradle C, set up by the pull of the weight J, and brings the bobbin B on to a brake surface D, by which its motion is instantaneously arrested. To piece up, the bobbin can be drawn forward into the position shown on the right hand side of the drawing in dotted lines, so that it can be turned back as much as required. The position of the parts before and after an “end” has failed is clearly shown on each side of the drawing respectively. It only remains to be said that a box T is fixed on the position shown, on which the wound bobbins can be placed prior to removal. Although the yarn is wound at a speed of 4,000 to 5,550 inches per minute, a broken end is usually arrested before it reaches the bobbin.
(399) In preparing thread for the lace trade it is the practice to remove the loose fibres, or “ooze,” projecting from its surface. This is done by a machine called a “gassing” frame, a sectional view of one head of which, as made by Mr. Stubbs, is shown in Fig. [211]. This represents one side of a machine only. The bobbin B is driven by frictional contact with a drum A, revolving rapidly, and is held in a weighted frame C, hinged at its inner end. C is raised by a bracket or arm D, mounted on the same pin. At the inner end of D is a slot in which a finger fixed on the stem of the burner E engages. The burner derives its gas from a tube G running along the frame, and is fixed in a swivel joint, being generally of the Bunsen type. The thread is drawn from the bobbin K, mounted on a freely revolving spindle, and is passed two or three times, as shown, over the grooved bowls H, these being formed with four grooves for the purpose. A guide I, receiving a longitudinal reciprocatory motion, guides the thread on to the surface of the bobbin B. As the thread passes rapidly through the gas flame from the upper end of the burner E, the “ooze” is rapidly singed off. When an end breaks or is “burnt down” the lever D is raised so as to lift the frame C and bobbin B out of contact with the drum A, and is sustained by a catch during the time of piecing. The same movement causes the burner E to be pushed at one side out of the path of the thread, and the restoration of the parts to the position shown again brings it gradually under the thread, but not until after the winding has commenced.
Fig. 210.J.N.
(400) In addition to these machines, where lace yarns are made it is sometimes the practice to use a “clearing frame.” This is an ordinary vertical spindle winding machine, but the yarn is passed through an adjustable nick, which is finely set, so as to catch or stop any knots or other unevenness in the yarn. This calls the attendant’s notice to the defect, and the thread is re-pieced, so as to remove the lump or knot. The best and most widely used “clearers” are those known as “Suggitt’s” patent, and consist of two cast iron plates, one fixed and the other adjustable. Vertical faces are formed on these, which come up to one another throughout their whole length, thus providing an opening or fine nick through which the yarn can be drawn.
(401) During the past few years it has become customary to dispense with the large flanged bobbins, such as are shown in Figs. [210] and [211], and to wind the yarn into a similar shape on a wooden or paper tube or spool. To do this it is necessary to give a very rapid reciprocal traverse to the guide rail, which is obtained by using a quick pitched cam, one revolution of which will give the double traverse required. In this way, instead of the yarn being wound in fine spirals, it is wrapped in coarsely pitched layers, and it is found that when wound in this manner a cylindrical spool or bobbin can be obtained which does not require the large wooden flanges to prevent it from unravelling at the ends. This object is attained in a winding machine made by Mr. Samuel Brooks by forming a slot, corresponding to the cam course, on the surface of the pulley driving the bobbin. The yarn is taken through the groove on its way to the bobbin, and the groove thus acts as a guideway or course. Messrs. Dobson and Barlow employ a quickly pitched cam, and have recently adapted the principle to gassing machines. Messrs. John Hetherington and Sons also make a machine on the same principle, but all the different methods employed have—where a guide rail is actuated—the fault that the working of the cam is rather noisy, and there is still room for an effective noiseless motion of this character.