Leading spool for upwards twist machines, in particular for apply paraffin for two-for-one twisters

摘要

In a two-for-one twisting frame where the twisted yarn is taken up on a bobbin via a traversing guide, the tendency of the yarn tension to change as the guide moves is offset by providing, in advance of the guide, a driven roller of paraboloid or hyperboloid form, over which the yarn travels on varying diameters as the guide moves. The roller may be asymmetrical where tapered packages are to be wound; it may have annular or helical grooves; it may be hollow and comprise a thin outer shell between end-flanges; or as in Fig. 6 (not shown) it may comprise a filling of resilient material comprising members 44, 45 hinged together and of which one is secured to the spindle, which members when secured together by eccentric flanges 49 secure in place the inturned ends of a thin shell. A member, with means for supplying it with treating-liquid or pressurizing-fluid, and having a surface of complementary form with, and in contact with, the roller may be placed above it, Figs. 7 and 9 not shown. A second roller in driving contact with, and of similar shape to, the feed-roller, may precede it, to deflect the yarn and tension it to an extent indicated by a scale. This roller may have a conical extension with helical grooves and cooperating with a cylindrical extension of the first roller to facilitate stringing-up.