GB1394093A - Method and apparatus for taking up a yarn onto a pirn after false-twisting - Google Patents

Abstract

1394093 Winding up yarn KANEBO Ltd 15 May 1972 [14 May 1971] 22607/72 Headings DID and D1F [Also in Division H1] False twisted yarn is fed by a delivery roller to a take-up roller which winds the yarn on to a cop, and the per cent take-up feed is varied continuously and as a function of time in accordance with a programme represented by a curve in the form of a reference stretch recovery characteristic curve for the wound yarn. The per-cent take-up feed is defined as the difference in surface speed of the rollers expressed as a percentage of the surface speed of the delivery roller. The reference curve is defined as a curve showing the relationship between the per cent stretch recovery of the thermally treated yarn and the location of the yarn in the configuration of a thermally treated yarn. Yarn 1, Fig. 5, is heat treated at 4, false-twisted at 6 and fed by delivery rollers 7 to be wound by take-up roller 8. The speed of roller 8 may be adjusted to vary the per cent take-up feed according to the programme shown in Fig. 4A, which is a straight line approximation of the inverse reference curve shown in Fig. 3A. The approximate curve may consist of less than three straight lines. Alternatively, the delivery roller speed, or the speed of both the delivery and take-up rollers, may be varied. The wind-up of nylon and polyester yarns is exemplified. Roller drive. Roller 8 is driven by an expanding-pulley variable speed gear controlled by a pulse motor receiving electrical pulses from generators associated with each straight line portion of the approximate curve. The pulse motor comprises, Fig. 12, an electromagnet 103 in housing 104, and a disc 106 mounted on shaft 112 and separated from the housing by balls 107. When the magnet receives an electrical pulse the disc is first attracted to the magnet so that the balls roll in tapered disc slots 108 to rotate the disc, and the disc is then back-rotated by spring 113. The oscillation of shaft 112 is converted by ratchet 109 into intermittent, uni-directional rotation of shaft 111 connected to the variable speed gear.