| 摘要 |
Thread-monitoring device for a sewing machine, which contains a sewing head with a sewing needle, having a rotatably fastened bobbin carrier for receiving an under-thread stock and for feeding the under-thread to the sewing needle during the rotation of the bobbin carrier, a plurality of sensing markings located on the bobbin carrier and arranged distributed along the circumference of the latter, a sensor sensing the markings, at the same time generating a series of electrical pulses, during the rotation of the bobbin carrier, a signal device and an electrical circuit, by which the signal device can be excited in the event of a specific change in the repetition rate of the electrical pulses, in order to indicate the corresponding state of the under-thread.
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