Sewing machine needle brake adjustment - varies braking forces between stitches according to type of stitches

摘要

To adjust the needle brake mechanism according to the type of stitch to be sewn, the required needle braking force is developed from the horizontal and vertical gap between stitches before the upper and lower threads have been knotted in the fabric for the next stitch. There is a proportional signal for the first stitch and the next stitch according to the position of the needle shaft. These signals are stored in sequence in a temporary store. Similarly for the advance slide, proportional signals for the first stitch and the next stitch are fed to another store. There are separate computers to develop difference signals. The system gives an automatic adjustment of the needle braking action, independent of the pattern control mechanism.