1. The head is sluggish
Treatment method: after washing with kerosene, refill the sewing machine oil; clean the shuttle bed; loosen the screws to ensure the gap.
Brief analysis of the reasons: the inner head of the shuttle bed is not only half-turn stagnation during operation, but also is accompanied by severe jitter and noise; the position of the feed dog is high or the dirt accumulates in the tooth gap, so that the feed dog touches the needle plate when it rises .
Treatment method: clean the shuttle bed and add a little sewing machine oil; clean or lower the feed dog; replace or straighten the needle bar.
Brief analysis of the reasons: the position of the feed dog is too forward or too backward, and touches the needle plate; the installation position of the needle bar is too high, and the needle clamp touches the case.
Treatment method: Adjust the position of the feed dog, align the needle again, and adjust the height of the needle bar.
Brief analysis of the reasons: the needle bar, needle bar sleeve, small connecting rod and other wear and tear are too large; the small connecting rod screw and the needle rod crank screw are loose.
Treatment method: replace the new needle bar, needle bar sleeve, small connecting rod and other accessories; re-tighten the small connecting rod screw and the needle bar crank screw to loosen.
Brief analysis of the reasons: the large pointed cone screw is worn or loose, the feed tooth touches the needle plate, and the needle pitch adjustment mechanism is loose.
Treatment method: Grind or readjust the large pointed cone screw, readjust the feeding tooth against the needle plate, readjust or tighten the screw of the needle pitch adjustment mechanism.
Brief analysis of the reasons: the wear of the shuttle and the shuttle bed causes a large gap, and the gap between the shuttle and the shuttle holder is too large, which causes an impact.
Treatment method: replace the new shuttle and shuttle bed, etc., adjust the distance or replace the new shuttle and shuttle holder.
Brief analysis of the reasons: the upper shaft, the lower shaft and the sleeve are worn, causing the upper and lower shafts to move; or the machine lacks oil.
Treatment method: replace the new upper shaft, lower shaft and shaft sleeve, or adjust the gap between the upper and lower shaft planes, pay attention to maintenance, and add lubricating oil on time.