(382) In Figs. 200 and 201 a special form of ring and traveller applied to a bare spindle is illustrated, these being made by Messrs. Platt Brothers and Co., Limited. The ring =B= has a groove =A= formed in it, in which a traveller =D= made of the shape shown is placed. The traveller has a loop or hook =E= near one extremity, and a second loop =C= nearer the centre. The yarn is first passed under the loop =E=, and then through =C=, thus giving a drag to the traveller at the point =E=, and causing it to travel round the groove. The loop =C= lies close up to the spindle when the yarn is at the nose of the cop, so that the yarn passes at once on to the former. The machine so constructed has been in use for some time, and it is found possible to stop it with the ring rail opposite the extreme point of the cop and re-start it without any considerable breakage of ends. In considering this portion of the subject past experience will form a base on which to found future efforts. A combination of a rapid traverse of the ring rail with some means of avoiding the direct pull of the yarn might be effective, but the subject is one for experimental work and not theorising. The latter is more likely to retard than aid in the solution of the problem. A differential speed of the spindles has been proposed, but no data exist by which a correct judgment can be formed. If by simple means an approximation to an equal twist can be obtained a great step towards the solution of this extremely difficult problem will have been made. The whole question is environed with difficulty and requires constant attention to a number of little points, but the advance made during the past few years is so remarkable that a good deal of hope can be entertained as to eventual success. In the meantime weft is being spun successfully on small wooden pirns which possess the great advantage of allowing the whole of the yarn to be unwound from them, and thus save the waste often made by “stabbed” cops. A frame for this purpose, made by Messrs. Howard and Bullough, is shown in Fig. 202, and about 400 grains of No. 20’s yarn can be wound on each.
(383) With reference to the details of the machine it has latterly become the practice to drive both tin drums positively, so that there is no variation in the twist of the yarn on different sides of the machine. Such an arrangement—made by Messrs. Asa Lees and Co., Limited—is shown in Fig. 203, the course of the ropes being clearly indicated by the figures attached. The lift of the spindles varies from 5 to 6 inches, and their gauge from 2-1/2 to 2-3/4 inches. The diameter of the front roller is usually 1 inch.