The interlock sewing machine is always jumping on the sewing head needle, how to deal with it

The standard height of the feed dog is 0.8mm from the plane of the needle board; the adjustment of the height of the feed dog: loosen the tooth fixing screw on the feed dog seat to adjust; the phenomenon after adjustment: it is lower than the standard height, which can prevent the fabric from rising If the wrinkle is too low, uneven stitch length is likely to occur; if the maximum stitch length is not the predetermined length, move the feeding limit plate set under the bottom plate of the machine head to adjust; adjustment method: positive feeding amount adjustment: loosen the screw Move the limiting plate upward (increase) or down (decrease) to adjust; reverse feed amount adjustment: loosen the fixing nut, and screw the adjusting screw in (increase) or out (decrease) to adjust.