Method of and apparatus for looping continuous filamentary strands

摘要

A continuous filamentary strand is fed to a looping zone where it forms serially connected loops by suspension on either side of a strand-engaging member, the loops then being continuously removed from the looping zone. By this means, strands, such as glass filaments, which are supplied at high speed may be collected at a slower rate either for further treatment or for the formation of looped strands. In one form of apparatus, Fig. 1, a strand 20 formed of glass filaments 21 drawn from a tank 23 by rollers 28 at speeds in excess of 10,000 feet per minute is caused to fall through an opening 43 in a hood 40 associated with a rotary catcher element 30 for temporarily collecting the strand 20 in looped form. The looped strand is drawn from the catcher element 30 through a neck 44 and wound on a spindle 50. In leaving the element 30, twist is applied to the looped strand. If desired, the strand may be severed into staple lengths. Instead of the enclosed element 30, a rotary element comprising a disc from the upper face of which pegs project may be employed. The strand is initially suspended on either side of the pegs and loops are thrown outwards by centrifugal force, other loops collect upon them and thereafter the looped strand is drawn through a guide eye and collected in twisted form. In another form of apparatus, Fig. 8, a rotary plate 67 is mounted upon a shaft 68 and carries packages 74 containing filaments, ribbons, cords, or other strands 75 of glass or other materials such as ribbons of a thermoplastic resin, which are drawn through a guide eye 77. A strand 78 is projected downwardly to strike the strands 75 and loop round them. Where the looped strand comprises glass and a thermoplastic resin, a heat treatment may be provided to form a resin-bonded cord or twine. Instead of strands being projected on to moving strand engaging members, they may be traversed by reciprocating the forwarding rollers to loop the strands over horizontally disposed fixed pegs. Alternatively, a strand may be passed through a rotary tube that is bent to give the strand a circular path as it strikes pegs projecting inwardly from a stationary ring; the strand loops over the pegs and is drawn off downwardly through an axial space between the pegs. In an embodiment employing a rotary ring with inwardly-projecting pegs, the ring may be supported by four anti-friction bearing blocks and driven by air jets. A further form of apparatus, Fig. 10, has a series of pegs 85 projecting from a rotary disc 83 for collecting a strand in loops and throwing them centrifugally on to a foraminous belt 93 passing over a suction box 94. By reason of the suction employed, the loops pile up on each other and are drawn from the belt through a false twist rotor 97. A modification of this apparatus has pegs attached to a travelling belt and replaces the foraminous belt by a stationary, perforated, arcuate upper surface on the suction box from which a looped strand is drawn along a stationary channel. Other forms of apparatus include rotary discs with projecting pegs for forming loops and throwing them off into a rotating funnel with an axial bore, or into a centrifugal spinning pot, or on to a sheet of paper or other material coated with adhesive and to which a further sheet is applied after bights of the strand have been laid upon the adhesive.