Rieter

Form of cops

Index

The cop (Fig. 83) consists of three visually distinct parts – the barrel-like base A, the cylindrical middle part W, and the conically convergent tip K. It is built up from bottom to top from many conical layers (Fig. 84), but constant conicity is achieved only after the formation of the base. In the base portion itself, winding begins with an almost cylindrical layer on the similarly almost cylindrical tube. With the deposition of one layer on another, the conicity gradually increases.

Each layer consists of a main layer and a cross-layer (Fig. 85). The main layer is formed during slow raising of the ring rail, the individual wraps being laid close to each other or on each other. The main layers are the effective cop-filling layers. The cross-layers are made up of widely separated, steeply downward inclined wraps of yarn and are formed during rapid lowering of the ring rail. They form the separating layers between the main layers and prevent the pulling down of several layers simultaneously when yarn is drawn off at high speed in winding machines. In the absence of such separating layers, individual yarn layers would inevitably be pressed into each other, and layer-wise draw-off of yarn would be impossible.

Raising and lowering of the ring rail are caused by the heartshaped cam and are transmitted by chains, belts, rollers, etc., to the ring rail (Fig. 86). The long, flatter part of the cam surface forces the ring rail upwards, slowly but with increasing speed. The short, steep portion causes downward movement that is rapid but occurs with decreasing speed.

 

Fig. 83 – The cop as a yarn package

Fig. 84 – Building up the cop in layers

Fig. 85 – Main layers and cross layers

Fig. 86 – The winding mechanism