Rieter

The aprons

Index

The upper aprons (Fig. 7, 2) are short and made either of leather or, more commonly, of synthetic rubber. They are about 1 mm thick and are held taut by tensioning devices (4). In contrast, the lower aprons (1) are longer and usually made of leather, although synthetic rubber is also used. They run over guide bars (nose bars) (3) to positions close to the nip line of the delivery rollers. Leather aprons are usually about 1 mm thick. The aprons cooperate with each other to guide and transport the fibers during drafting and they exert a very significant influence on the drafting operation. It is important that the aprons should extend as closely as possible to the nip line of the front rollers. The guiding length, referred to as the cradle length (a), must be adapted approximately to the staple length. In accordance with data provided by Rieter, the following cradle lengths should be used:

 

Cradle length (mm)
Material

short

Cotton up to 1 1/8˝; 40 mm synthetic fibers

medium

Cotton above 1 1/8˝; 50 mm synthetic fibers

long

Synthetic fibers, 60 mm

 

 

Fig. 7 – Apron guidance in the drafting arrangement