Patent GB-329620-A (GB)
Title: Improvements in or relating to the manufacture or treatment of artificial threads orfilaments
IPC: D01F2/28
Filed: 1928-12-20
Abstract: 329,620. British Celanese, Ltd., Dreyfus, H., and Taylor, W. I. Dec. 20, 1928. Tension arrangements.-Artificial filaments or threads are stretched by passing them round a roller or the like to which a drag or braking action is imparted and which is rotated by applying a sufficient stress to the filaments or threads. The drag is preferably adjustable in amount, and the drag roller is preferably provided with positive driving means for use at the beginning of the operation, the positive drive being cut out, preferably gradually, as the filaments take over the drive. The drag may be inoperative at the beginning of the operation and may be applied, preferably gradually, during the removal of the positive driving means. The stress necessary to draw the filaments round the drag roller may be applied by a traction roller round which the filaments pass, or by nipping rollers, or by winding or twisting and winding devices. Two or more independently adjustable drag rollers may be used, and additional traction devices may also be used. The method may be applied in the course of production of the filaments by dry or wet spinning, or subsequently thereto, e.g. during winding or rewinding, and is particularly applicable to the treatment of filaments of cellulose acetate or other organic derivatives of cellulose. In Fig. 1, filaments 8 from a spinning cell 9 are passed round a drag roller 10 to a stretching roller 11 and thence to a bobbin 12. Drag is imparted to the roller 10 by a leaf spring 14 having a pad 15 bearing against the roller, the drag being adjustable by a thumb-screw 16. For starting up, positive driving means for the roller 10 are provided comprising a pulley 41 driven by a belt 42 from a pulley 43, which drives the roller 11 also. The filaments may pass between the roller 11 and a roller 47, instead of round the roller 11, and these nipping rollers may be corrugated, toothed, or roughened. A modified apparatus is described in which the drag is imparted by a band passed round the roller or round a pulley on the roller shaft, one end of the band being anchored and the other end secured to a spring. A further modification is described in which the roller is braked by a centrifugal governor driven at a speed proportional to that of the roller. In Fig. 4, an air brake 26 is driven by a friction pulley 27 bearing against the inner periphery of the drum, the braking action being adjustable by means of an axially movable casing 28. A similar apparatus in which the brake rotates in a casing containing liquid is described also. In Fig. 7, a disc 32 secured to the shaft of the roller 10 rotates between the poles of an electromagnet 34, and positive driving means for the roller 10 are provided, these comprising fast and loose pulleys 36, 37. A belt fork 38 used to shift the belt from one pulley to the other is connected by a rod 39 to the arm 40 of a rheostat 35, so that the resistance in the circuit of the magnet 34 is cut out gradually as the positive drive is removed from the roller 10. Specification 323,790, [Class 120 (iii), Yarns &c.], is referred to.