Digital Monitoring of Needles for Circular Knitting Machines

The optical head projects a narrow spot of light onto the passing needles, which reflect a part of the light. These light pulses are fed to the control unit via fibre-optic cable. The control unit automatically adapts to the needle sequence corresponding to the machine speed and the gauge of the needles. If a pulse has not been received at all or not at the correct position due to a needle defect, the machine control is triggered to stop. Simultaneously with the stop signal, a needle counter begins to work. It indicates the number of needles that have to run past until the optical head reaches the position of the defective needle. For the machine operators this is a valuable support when it comes to locating and to replacing a defective needle. Missing needles can be masked out e.g. when working with cutting line or when producing patterns. To avoid false stops, the number of revolutions before stopping the machine is adjustable.