Patent GB-1305758-A (GB)
IPC: D02J1/22
Filed: 1970-09-03
Abstract: 1305758 Apparatus for drawing filaments IMPERIAL CHEMICAL. INDUSTRIES Ltd 27 Aug 1971 [3 Sept 1970] 42223/70 Heading B5B Apparatus for continuously drawing a filament comprises a filament advancing roll 2 adapted for rotation under the speed controlling influence of a motor (not shown) and a plurality of other rolls 4, 5, 8, 9 each adapted for rotation under the speed controlling influence of surface contact with the advancing filament before it reaches the advancing roll 2, at least two of such plurality of rolls (i.e. 4 and 5) being coupled for rotation at predetermined surface speed ratio corresponding to a required draw ratio. Thus in Fig. 1, a continuous filament 1 passes from a supply means not shown through an advancing roll 2, driven by means not shown, against which roll the filament is held in contact without slip by a nip roll 3. An idler roll spaced apart from and skewed with respect to the advancing roll 2 may be used instead of the nip roll 3. Two rolls 4 and 5 are mounted for free rotation but coupled by gears 6 and 7. Two further rolls 8 and 9 are mounted for free rotation with axes slightly skewed with respect to the axes of rolls 4 and 5 respectively. A steam heated enclosure 10 is provided between rolls 8 and 9. Thus the filament, advancing under the influence of roll 2 causes rolls 4, 5, 8 and 9 to rotate and is thereby caused to draw in the heated enclosure to a ratio dictated by the gear ratio between gears 6 and 7. The apparatus of Fig. 3 functions in the same way as that of Fig. 1, the filament 16 passing a number of times around rolls 111 and 121 on their relatively skewed rotors 11 and 12, and passing through the heating enclosure 13 to the draw roll sections 112 and 122 on the said rotors before passing to advancing roll 14 and nip roll 15. The ratios of the diameters of sections 112 and 122 to 111 and 121 are equal, and advancing roll 14 is positively driven. The apparatus of Fig. 4 may be used for drawing and relaxing. A first rotor 20 comprises a feed roll section 201 and a draw roll section 202. A second rotor 21 comprises a draw roll section 211 and a relax roll section 212. A separate feed roll 22 and relax roll 23 are provided adjacent rotors 20 and 21 respectively and a forwarding roll and nip roll 24 and 25 are provided adjacent roll 23. Operation is similar to the apparatus of Fig. 3. Heated enclosures may be provided for drawing and relaxing or the rolls may be heated or mounted within a heated enclosure. A triple stepped rotor development of the apparatus of Fig. 3 will provide for two stage drawing, and in general multistage drawing may be provided for by coupling more than one pair of rolls. Fig. 5 illustrates a multistage drawing apparatus. A closely spaced pair of self threadable parallel grooved rotors 31 and 32 of the type disclosed in Specification 1,279,535 have varying groove depths so as to provide feed roll sections 311 and 321, intermediate roll section 312 and 322, and draw roll sections 313 and 323. The rotors are freely rotatable in bearings 33 and 34, mounted in an enclosure 35 which is heatable. The apparatus comprises also a motor driven advancing roll system not shown. In operation a filament 39B issuing in the direction of the arrow from supply means not shown to advancing means not shown is engaged in the back groove of rotor 32 and then threaded on multiple figure of eight loops round the noses of the rotors. The advancing filament then migrates back along the rotors and threads itself into adjacent grooves. The apparatus is also useful in association with filament supply means which do not deliver a filament at predetermined speed. Thus a filament may be withrawn from a bobbin or other package by the advancing roll and no driven feed roll is needed. Thus the apparatus can be used with filament extrusion apparatus to provide for integrated spin-draw. In such an association no external driving means are needed for any machine element between the extrusion pump and a package winding mechanism. The apparatus is especially suitable for the continuous drawing or relaxing of melt spun synthetic polymer filaments, and especially as apparatus for drawing or relaxing a number of similar filament yarns separately and simultaneously. It will be seen that the coupled rolls perform the functions of feed and draw rolls and may be associated with any melt drawing means such as heaters or snubbing means.