Patent GB-640454-A (GB)
Title: Improvements relating to drawing heads for slivers of long staple fibres
IPC: D01H5/22
Filed: 1947-01-22
Abstract: 640,454. Drawing devices for textile fibres. MACKIE & SONS, Ltd., J., and MACKIE, J. P. Jan. 22, 1947, Nos. 2048 and 25652. [Classes 120(i), 120(ii) and 120(iii)] A slip draft drawing head for slivers of long staple fibres, such as jute, hemp, or flax, has, between feeding and drawing rollers, a large driven roller having a circumferential length at least equal to the length of the sliver path between the feeding and drawing rollers and making at least 25 per cent surface contact with the sliver and also between the feeding and drawing rollers, two or more coacting rollers situated near tc the nip of the drawing rollers. Guides are preferably provided so that slivers entering through the feeding rollers will pass automatically right through the drawing head. In one modification, Fig. 1, a sliver is led through a conductor 16, between a large roller 17 and a retaining roller 18, beneath a guide member 73, between the large roller 17 and a control roller 20, beneath a guide member 75 into a conductor 21 gapped intermediately to allow the sliver to be acted upon by a driven slip draft roller 22 and co-acting pressing roller 23. From the conductor 21 the sliver goes through the nip of drawing rollers 24, 25 and passes into a narrowing conductor 37, to issue through rollers 38, 39 into a crimping trap 41 which has a weighted tongue 42. Rollers 18, 20, 23, conductor 16 and guide members 73, 75 are carried on a frame 58 pivoted at 57 and weighted to increase the grip of the retaining roller 18 by a weight 82 operating through a lever 80 and link 78. Rollers 20, 23 are loaded by weights 61a, 67a and roller 25 by a weight 35 operating through lever .33. and link 31. In order to turn back on to the conductor 37 any sitver end or fibres which may tend to lap around the roller 24, a rubbing roller 44 is pressed against roller 24 by a weight 47. The rubber roller 44 is covered with felt flannel or other soft material and is driven in the same direction as roller 24 by belt transmission from the shaft of the large roller 17. The rollers 17, 18, 20, 22, 23 are preferably corrugated. When two slivers are treated side by side, the large roller 17 may have a central or intermediate flange and the rollers 18, 20, 22, 23 may be mounted in pairs, each pair independently of the other pairs. The slivers may be combined in the narrowing conductor 37. The upper roller 23 may be driven by the teeth of the lower roller 22, but the teeth of the latter roller may be reduced in height where the slivers pass to facilitate the slip drafting. In another modification. the roller 17 has no flanges but side and intermediate guides are provided on a conductor which extends over the roller 17 from the retaining roller to the drawing rollers. Alternatively, this conductor may provide side walls for the roller 17, but ,the roller 17 may have an intermediate flange formed integrally with it. in a further modification, Fig. 11, separate retaining rollers 513, 518 are employed, the large roller 517 is flanged and a guide plate 573 extends over it. The guide plate 573, a slip draft roller 523 and the upper retaining roller 518 are mounted on a frame 558 pivoted at 557 and weighted at 511. This arrangement may be modified by dispensing with lower retaining roller 513 and pressing roller 518 against the large roller, or the guide plate 573 may be in two parts to allow a control roller to bear on the top of the large roller. Further modifications employ a belt passing round the large roller and a lower slip draft roller, as shown in Fig. 13. The large roller 617 may not be flanged, but it may have guide walls provided independently and be corrugated. It is stated that the upper slip draft roller 623 may be driven faster than the lower roller 622. for example, about 6 per cent faster. According to the first Provisional Specification, a belt passing around at least a pair of upper rollers may be employed, or a belt may be pressed against the underside of the large roller and the sliver may pass between the roller and the belt, alternatively two belts may press on the sliver. A counterweighted roller may be used to tension a belt. Also according to the first Provisional Specification, a slip draft device may comprise a group of three rollers, one of which is driven, and a conductor having side cheeks embracing the lower portion of the upper slip draft rollers and the upper drawing roller. According to the second Provisional Specification, where drafting belts are used, these may be corrugated. Specifications 407,671, 407,690, 407,706, 407,707, 422,015, 509,493 and 516,466 are referred to.