Zigzag sewing machine has a needle that alternately moves up and down within a certain range in the left and right directions to pierce the seam material on the needle plate, and a rotating hook complete that rotates under the needle plate to maintain the thread winding and take out the thread; The upper thread loop formed by the downward movement of the needle and alternating left and right on the lower side of the sewing material is captured by the hook point set on the rotary hook and interwoven with the lower thread.
During the sewing process of this zigzag sewing machine, due to various external forces, the needle may bend and sometimes deviate from the position between the falling needle tip and the track of the hook tip. When this position deviation occurs, errors in catching the thread caused by the hook tip, conflicts between the needle and the hook tip, etc., may cause various problems that hinder normal sewing.
In order to prevent the occurrence of the above problems, a zigzag sewing machine is disclosed in Japanese utility model Kaiping No. 3-13976 (1991), which is equipped with a needle frame that rotates integrally on a part of the rotary hook. Through this needle frame, the needle tips of the needles that fall in their respective positions on the left and right sides are supported, so that the needle tips can determine the correct position relative to the track of the hook tips.
The composition of the needle holder is to fix a part of the needle holder plate fixed as an integral part on one side of the rotary hook, retain one side of the center side, and then make a rectangle, and bend the retained side as a foot towards the side of the rotary hook, and then stand up parallel to the side of the rotary hook.
As mentioned earlier, the zigzag sewing machine must accurately support the needle tip at the respective dropping positions on the left and right sides of the rotary hook due to the needle dropping within a certain range on the left and right sides. The zigzag sewing machine disclosed in Japanese utility model Bulletin 3-13976 solves the problem by designing a support surface for the needle tip and setting a guide surface on the needle holder to guide the needle tip to the support surface.