Under-thread feed device and method for feeding an under-thread

摘要

An under-thread feed device for a sewing machine has an under-thread bobbin housing, an under-thread bobbin exchange device, a thread removal device and a winding device. The under-thread bobbin housing is inserted removably in a sewing-machine shuttle and receives an under-thread bobbin having a thread wound on it. The under-thread bobbin exchange device extracts the under-thread bobbin housing from the shuttle and inserts the under-thread bobbin housing, containing the under-thread bobbin with the new thread wound on it, into the shuttle. The thread removal device removes the thread from the under-thread bobbin received in the under-thread bobbin housing which is extracted. The winding device winds a predetermined quantity of a thread around the under-thread bobbin after the thread has been removed from it.