The accurate feeding action of the interlock sewing machine can reduce the probability of jumping. The main aspects of the machine's daily impact on the feeding action are closely related to the feed dog height, presser foot pressure, differential feed, needle pitch density, and speed of use.

The main theory of this article is that the stability of the triangle loop on the back of the looper depends on the stability of the feed action and the correct fit of the thread take-up cam. If the feeding action is unstable, the triangle loop will be deformed or suddenly become too small to allow the needle to enter the triangle loop.

The principle to adjust the height of the feed dog is that when the feeding action is completed, the feeding tooth should be completely returned from the bottom of the needle plate, and the action of reversing the sewing material is not allowed at all.

The presser foot pressure is such that the sewing material does not slip to the operator side.

When the elastic material is too large or the operator pulls the material into the arms too much, the amount of differential feed must be increased.

The stitch length of the small triangle ring is also small, so the density should be appropriate, and should not be small in the possible range.

If the speed is too fast, the sewing material will float or will not be pressed by the presser foot to affect the stability of the wire loop.