3, the type and role of the hook moon circle

After the hook line time is adjusted according to the sewing needs, the time for the stitch to bypass the bobbin from the hook is also determined. When sewing thick material, the hook tip of the hook is adjusted later than the needle, and the time for the loop to escape from the hook is later. In addition, when the thick material is thick, the line needs to be the largest and the remaining line is small, and the tip of the bobbin is in the idle circumference. Generally, it is not possible to hook the escaped loop again. However, when the thin material is sewed, the tip of the shuttle is adjusted ahead of the needle, and the time for the loop to escape from the hook is often earlier than the time when the tip of the shuttle reaches the center line of the needle during the idling cycle, and the thread is less when the thin material is sewn. There are many lines, and it is easy for the tip of the shuttle to hook again from the hook in the idling cycle, and the two hook lines are abnormal.

When the hook is normally hooked, the thread take-up lever is in the line-release phase. After the loop is released from the hook, the thread take-up rod starts to take off quickly. If there are two hook lines, it will inevitably conflict with the take-up of the thread take-up, which will definitely lead to disconnection.

In order to avoid two hook lines, effective measures have been taken in the design of the hook structure. Comparing the hooks of the slit-thick and thin-stitch sewing machines, it can be found that the structure of the moon ring is clearly different whether it is a vertical horizontal shuttle, a horizontal horizontal shuttle, or a vertical rotary hook.

The moon circle of the sewing machine of the thick sewing machine only functions to form the shuttle trunking, and the tail end is short. This is advantageous for the thick line when the thick material is sewed out of the hook earlier, and is pulled into the sewing material by the take-up action of the thread take-up as soon as possible.

The moon circle of the sewing machine of the thin sewing machine is not the same, and its tail end is serpentine-shaped, and the length is long and gradually shrinks. The moon circle of the sewing machine of the thin sewing machine not only needs to form the shuttle trunking, but also the tail end is responsible for guiding the off-line. It can be observed that the upper thread of the thin material is pulled out from the hook. In the process, it is first turned over to the tail of the moon circle, and then gradually slides out from the tapered tail during the continuous rotation of the hook. Because the angular position of the tip of the moon's tail is already late at the tip of the shuttle, the loop that comes out of the end of the moon's ring is not hooked by the tip of the hook anyway. In this way, the hook line is reliably avoided twice.

If no matter how the adjustment is made, the upper thread will not be received well, and the floating line will appear on the reverse side of the sewing material. It should be checked whether the moon circle is not suitable. It is best to change the moon circle with a short flat tail (smooth flat).