Rieter

The flyer top

Index

The manner in which the roving is carried along and guided at the entrance to the flyer determines the degree of twist and the winding tension. Where the roving has only low twist or is coarse, so that there is a risk of false drafts, the strand passes through the flyer top to the guide groove with half a wrapping (Fig. 12, A). A one-turn of wrap, as shown in (B), is selected for high-speed frames winding large packages with high twist levels. The wrap permits better control of roving tension and the package build becomes more even owing to the harder coils. Older flyers have flyer tops of smooth metal. However, most modern flyers have an insert of rubber formed with grooves, notches or indentations (Fig. 13). These flyer inserts exert a strong influence on the level of twist in the roving between the drafting arrangement and the flyer, and also on winding conditions at the bobbin. Their formation enables them to carry the roving along substantially better while imparting twist, and they additionally insert the very favorable false twist. One result of this false twist is that the roving is already strongly twisted in the unsupported length leading to the flyer. Roving breakage rates in the spinning triangle are thus reduced, and fly and lap formation are decreased. A second result of the false twist is a more compact roving, which increases the capacity of the bobbin and permits higher flyer speeds. The capacity of the bobbin is still further increased because the compactness of the roving permits winding with higher tension.

Fig. 12 – Entry of the strands into the flyer top

Fig. 13 – The flyer top