GB1190214A - Method and Apparatus for Arranging a Weft Filament in a Sheet of Tows of Warp Filaments - Google Patents

Abstract

1,190,214. Looms; drafting. rolls; woven fabrics. ROLLS-ROYCE Ltd. 13 Dec., 1968 [15 Sept., 1967; 4 Dec., 1967], Nos. 42158/67 and 55102/67. Headings D1E, D1D and D1K. Tows of polyaorylonitrile warp filaments are held together as a sheet, ,to facilitate, for example, subsequent heat treatment, by at least one inserted polyacrylonitrile weft filament. As shown in Figs. 1 and 2, tows 4 of filaments are fed direct from side creels 1 around guides 5 and 7 into a warp sheet 10 which is passed to a weaving zone '14 where alternate groups of filaments are raised by castellated member 16 to form a shed through which loops of a weft filament 15 from a 'bobbin 23 are inserted by a hollow ,needle 20. Repeated operations of member 16 raise slightly different groups of filaments so that a loose 'random weave is obtained. The member 16 is carried by a frame 17 which is vertically reciprocated by means not shown. An additional castellated member 18 with its teeth staggered in relation, to 16 may be employed, the two members being alternately operated for shedding to produce a more definite weave. A clamp 27 operated by a solenoid 25 is provided for temporarily the end of each inserted weft loop. The insertion of the weft may alternatively be effected by air or water jets in which case single measured lengths of. weft are cut and inserted. In another arrangement. Fig. 4, the tows 33 from, the creed pass through nylon guide tubes 35 in a plate 36 and are controlled by teeth 37, "the spacing of which can be adjusted to regulate the density and width of the sheet 40. The sheet is then passed over rollers 41, separating bars 42, 43, spreader unit 45 and a warp tension detector tube 51, the pressure in which, due, for example to an entangled or knotted tow, controls a switch 52 to stop the .apparatus. The sheet 40 is then passed through, drafting rollers 53, under and over bars 54, 55, 56 and through drafting rollers 57 having a slightly greater peripheral speed than 'the rollers 53. One of the rollers 53 may be a worm roller with a square thread to modify the drafting action on the sheet. Shedding in this arrangement is effected by toothed'' wheels 64 on carriages 61 slidable across the sheet from both sides to the centre by a pneumatic or hydraulic ram 63. The weft 70 is ..inserted in loops 71, 72 alternately from the two sides of the loom, to overlap at the centre, by hollow needles 65 on the carriages 61 extending adjacent the wheels 64. The wheels 64 are rotated by engagement of their teeth in the warp sheet so that after each shed they re-engage a different group of warp filaments to provide for a random weave. The wheels may be 'lifted on -outward movement to clear the warp. Weft detector devices 74 which may be photo-electric, capacitive or electro-mechanical and may incorporate fluid-logic devices may be employed to stop the apparatus on weft breakage. An infra-red heater 77 may be provided to stretch the material and increase its modulus of elasticity or high frequency dielectric heating may be used. The completed sheet is wound onto a beam driven from an electric motor through a slipping hydraulic connection to maintain the desired tension or a limited torque motor may be used for this purpose.