1427373 Spinning yarns E BOBKOWICZ and A J BOBKOWICZ 17 Oct 1973 [29 Nov 1972] 48321/73 Heading DID, D1F, DIN and D1W In the production of spun yarn, staple fibres are helically twisted by an air vortex within a chamber and consolidated with a tacky substrate to form yarn which is linearly wound on a collecting roll. The substrate may be introduced e.g. directly extruded, into the chamber so that the fibres are helically twisted thereabout and the resultant yarn may thereafter pass through a false-twist spindle by which additional retained twist is imparted. The consolidation and also condensing and perhaps the false-twisting may occur within a circumferential V-shaped groove of a rotatable roll into which the twisted fibres and substrate are introduced separately or as a combination. The groove may be slotted so that air suction and/ or blowing may effect a holding and wrapping action on the fibres etc over part of the yarn path in the bottom of the groove and thereafter the consolidating and condensing etc. action in the middle of the groove. An additional ready made (carrier) strand may be untroduced into the chamber and/or the groove and the yarn is formed therearound. Additional fibres of similar or different nature and form may be introduced directly into the groove. The staple (initial or additional) fibre may be any natural or man made fibre including cast, asbestos, glass or metallic. The substrate may be in the form of extruded strands or filaments or a spray or mist of particles; the material(s) thereof may be polyethylene, polypropylene, polyamide, polyester, polyvinylchloride, thermosetting material such as acrylic latices, phenolics, urea compounds, alkyds and epoxies, acrylonitriles, rubber and silicone based compounds, polyurethanes, plastisols. In a chamber 10 of the apparatus of Fig. 1, an air vortex is produced by sources of compressed air 12 and 13; attenuated fibres are fed from a licker-in roller 14 (to which a fibre web 16 is supplied by roller 17) and blown into the vortex by pneumatic device(s) as at 18; a tacky substrate is extruded from a nozzle 19; a filament 21 or yarn 22 is introduced as a carrier. Air blowing devices 23, 24 assist downward movement of the materials in the vortex. The (lightly) twisted strand 20 leaving the chamber is formed into yarn in a groove 26 in roll 25, slotted or apertured at 27, to which additional fibres from a web 30 are fed by roller 31 and licker-in roller 28. The consolidated yarn is then forwarded through tension roller 32 to the winding arrangement 33 and/or through oscillating roller 35, 36, to condense the yarn further, or through a false-twister 37. The embodiment of Fig. 2 has two air vortex chambers 40a, 40b supplied with compressed air 41 and fibres from two licker-in rollers 42a, 42b each comprising needles 43 and blades 44; fibres etc are consolidated within the groove 46 of a collecting roll 45 to which they are fed by suction devices 49, 50 into channels 47 thence by blowing devices 51, 52. In another apparatus, Fig. 3, compressed air 41 produces an air vortex in a chamber 40 into which fibres from a licker-in roller 42 (and originating from a fleece or web 56 fed by supply roll 57) and a carrier strand 60 (passing through an extruder 61 to be coated with a tacky substrate) are introduced.
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