Analysis of the hooking mechanism of the four-needle six-thread sewing machine with curved arm

In order to allow the majority of operators and maintenance personnel to have a more in-depth understanding of the crank arm type four-needle six-thread sewing machine, so as to better judge and deal with the problems in the use process, this article only describes the working principle of the hooking mechanism. etc. have been analyzed, hoping to provide useful help to the readers' operation and use.

As a model required for production in the modern garment industry, the crank arm type four-needle six-thread patch sewing machine is widely used in underwear, long tube silk and other needs with its special sewing principle and crank arm type small cylinder structure. Place for stitching and sewing. This model has firm seams, neatly trimmed edges without hemming, beautiful stitches, and can sew multiple processes at one time, so it is favored by the majority of users.



Most of the four-needle six-thread patchwork sewing machines currently on the market can be divided into“single cut”and“double cut”two kinds. The main structure and basic principle are the same, the only difference is that the feed guide and the presser foot change. The whole machine can be decomposed into three major mechanisms: needle bar piercing and thread take-up mechanism, differential feeding and adjusting mechanism and looper hooking mechanism.



Due to the complex structure of the crank arm type four-needle six-thread sewing machine and high precision requirements, it is relatively difficult to debug. In order to allow the majority of operators and maintenance personnel to have a more in-depth understanding of the articulated arm type four-needle six-thread sewing machine, so as to better judge and deal with various problems in the use process, the author only hooks the model below. The working principle of the wire mechanism part is analyzed, hoping to provide useful help for your operation and use.

The state of the looper hooking mechanism directly affects the formation and stability of the stitches in the sewing process of the four-needle six-thread sewing machine, so it occupies an extremely important position in the entire machine structure.



Below, we first analyze the working principle of this set of institutions:

The movement track of the curved needle of the curved arm type four-needle six-thread patch sewing machine is an ellipse, which is composed of two groups of movements of the back and forth movement in the back insertion direction and the left and right swing in the hooking direction. It is divided into two paths for analysis below.

The movement of the looper in the forward and backward directions:

When the main shaft rotates clockwise, it drives the feeding eccentric wheel and the feeding link assembly to move up and down.

The feeding dog adjusting seat is connected with the spherical hinge of the feeding connecting rod ball crank and swings back and forth around the feeding lever.

The front and rear links of the looper are connected with the feed dog adjusting seat by means of adjustment screws. When the feeding dog adjusting seat swings, the front and rear links of the looper are driven to push the looper shaft stopper fastened with the looper shaft to move forward. When retreating, the backward movement of the looper shaft is realized through the contact between one end of the looper shaft sleeve and the looper shaft shoulder.



By adjusting the distance between the adjusting screw on the front and rear links of the looper and the lever shaft, we can change the forward and backward movement strokes of the looper shaft sleeve and the looper shaft, so as to adjust the back insertion of the looper and the straight needle. After the looper shaft casing guide rod is connected with the casing, the sliding guide rail formed with the looper shaft casing restricts the remaining five degrees of freedom to ensure that the looper shaft only moves in the front and rear directions.

Movement in the direction of the looper hook:

When the main shaft rotates clockwise, the eccentric mechanism composed of the adjusting screw and the ball link drives the looper driving link and the looper lever to reciprocate around the looper lever axis.

The looper ball crank connects the looper connecting rod and the looper shaft, so that the looper shaft reciprocates in the hooking direction with the rotation of the main shaft.

When the eccentric wheel rotates around the main shaft, it drives the connecting rod and the feeding dog adjusting seat to swing around the feeding lever shaft. sports.

As we all know, by adjusting the distance between the pieces, we can change the amount of movement of the looper before and after (inserting back).

Its standard value is 2.4 mm.

We can set the adjusting screw into the chute at the end of the main shaft to form an adjustable eccentric mechanism. When the main shaft rotates, one end of the looper driving link and the looper lever is driven to swing around the looper lever shaft, while the other end is connected with the looper link to drive the looper shaft to swing around the looper bushing.



This swing angle is the swing angle in the direction of the looper lead, and its size is adjusted by the adjusting screw. According to relevant theoretical regulations, the standard swing angle is 55°40'.