Open-end spinning unit sliver feed - has controlled clamping points to reduce sliver volume during yarn repair

摘要

The system to control the sliver feed to an open-end spinning unit, while a broken yarn end is being reversed into the spinning rotor to be spliced into the end of the newly-spun yarn, has adjustable clamping points working in conjunction with the fibre opening unit for the sliver. More spec. the clamping points which are set according to the required staple fibre length, are formed at one end by the feed roller and a sprung trough for the opening roller to work on the sliver, the other clamping point being located along the line of sliver travel where the sliver is pressed against a guide. One arm of the trough is in the form of a double lever between the clamping points which also acts as a guide for the pressure unit. A sensor controls the action of the opening roller and clamping point by switching it in and out of action according to the required sliver feed according to the operating condition of the spinning rotor. The system ensures that a reduced volume of drawn staple fibres is fed to the rotor, relative to the reduced speed of the spinning rotor during the splicing phase, to prevent a build-up of fibres through an overfeed of the sliver.