GB1422857A - Apparatus for chopping strand of fibres into short lengths - Google Patents

Abstract

1422857 Stapling fibres JOHNS-MANVILLE CORP 23 Oct 1973 [26 Oct 1972] 49266/73 Heading D1F In a chopper for cutting continuous strands of fibres into short lengths by passage of the strand between radially projecting blades of a rotating roll and the surface of a back-up roll, the rolls are cantilever mounted and at the free ends thereof the cylindrical working surface of the back-up roll extends beyond the region engageable by the blades so as to provide a surface around and along which strand is led into the chopper. As shown in Fig. 1, bushings 11 issue filaments 12 of molten glass which are withdrawn at high speed over a size applicator 13 to a gathering wheel 14 and strands 15 formed thereby are guided by wheels 16 and 18 to a chopper 17 wherein the strands are carried over a back-up roll 19 (the pulling force of which is enhanced by a polyurethane facing 21 and the action of a pneumatically loaded pressure roll 22) and severed by blades 28 on roll 29 into short lengths which are projected onto a moving collecting surface 51. As shown in Fig. 3, the tapered tip of roll 22 projects beyond the free end of roll 21 and both project beyond the end of roll 29 to facilitate entry of the strand: also, an auxiliary starting mechanism is formed by a conical extension 53 of roll 19 and a starting roll 54 bearing thereon, strand being fed between the rolls and accelerated to the working speed of the rolls in the chopping region as the strand is pulled into line between the adjustably traversed guides 18 and roll 29. The roll 54, formed by replaceable stacked discs 56 of resilient material such as polyurethane or rubber for flexibility, is carried in a bracket 58 which is adjustably positioned by telescopic elements 59, 61, of a bracket 57. The drives of rolls 19 and 29 are independent and the rotational speeds thereof relatively adjustable. In another embodiment, Fig. 4 (not shown) the strand is manually laced into the chopper and the rolls brought up to working speed.