In addition to the left and right movements of the curved needle, there are also front (toward the operator) and back (away from the operator) movement. Note that the fastest movement of the looper back and forth is placed at the limit position of the left and right movement of the looper, and the movement of the looper back and forth must be minimized when the looper moves to the left to reach the needle position. At this time, attention should be paid to both the left and right extreme positions. It is necessary to prevent the needle from scraping when the looper moves to the left and to prevent excessive scraping of the needle when the looper moves to the right. Of course, you can also adjust the forward and backward movement of the looper and rotate the angle of the needle bar a little clockwise to achieve the best results. Some machines can adjust the range of forward and backward movement of the looper, while others cannot.
When the needle is lowered to the lowest position, the distance between the curved needle tip and the right needle is 3-4mm. When the needle rises, the looper moves to the left. When the looper tip reaches the center of the right needle, the bottom of the looper tip is 2.5mm above the eye of the needle. At this time, the gap between the looper and the needle is 0-0.05mm.
When the needle descends to the back of the looper, the eye of the left needle and the threading hole in the looper head meet. At this time, the back of the bend needle is allowed to slightly touch the needle, but it is best not to scratch or the lighter the better.
Adjustment of the front and rear needle guard
The principle to be followed when adjusting the front and rear needle guards is: the contour line of the front and rear needle guards from the direction of the operator should be consistent with the line of the needle tip. In order to prevent the needle from jittering on the needle guard, the guard needle is close to the side of the needle. It should be chamfered appropriately. The front needle guard (close to the operator) not only serves as a needle guard but also prevents the sewing thread from forming a loop in front of the needle eye (close to the operator), so that the loop behind the needle eye is formed smoothly. The rear needle guard must act as a needle guard without blocking the smooth formation of the thread loop.
Due to different manufacturers and different machine models, the shape of the front and rear needle guards and the allowable adjustment range are some distance from the ideal state. Maintenance personnel are required to move as close as possible to the principles that need to be followed in the actual situation.
When the needle moves down, the front and rear needle guards should move away from the needle. When the needle rises from the lowest position, the front and rear needle guards must move toward the direction of the needle.
When the needle is lowered to the needle guard position, the needle guard should hide from the starting needle to avoid rubbing against the needle.
When the looper tip moves to the left to the right needle position, the front and rear needle guards begin to work. The gap between the front (close to the operator) needle guard and the needle is 0.1-0.3mm, and the rear guard and the needle The gap between them is 0-0.1mm.
Adjustment of looper thread take-up cam
The design of the looper thread take-up cam is different from the factory, and some of the size and shape may be slightly different from the actual need. If the gap is too large, it will easily cause the jumper and increase the difficulty of maintenance. The function of the looper thread take-up cam is: when the looper moves to the left, it will provide the looper with the amount of sewing thread needed for its movement and knitting stitches, and when the looper moves to the right, it will take back the excess sewing thread in a timely manner. .
Special attention is needed: in order to facilitate the needle entry into the triangular thread loop on the back of the looper, the looper thread take-up cam needs to be used to make the looper thread under tension when the needle enters the triangular thread loop. However, excessive tension will cause the looper thread to break and the looper thread appears to be too tight on the back of the sewing material.
The correct adjustment standard for the looper thread take-up cam is: when the needle is down and the left needle tip reaches the lower edge of the looper, that is, when it enters the triangular thread ring securely, the looper thread on the looper thread take-up cam is located on the thread take-up cam. The highest point.
The speed of the looper thread take-up cam can be slightly adjusted on the basis of the above standard. If the speed of the looper thread is adjusted faster according to its own rotation direction, the stitches on the back of the sewing material will appear to have a loose looper thread tension, and vice versa.
The adjustment of the tensioning needle and the tensioning needle thread board
For some types of machines, the timing of tensioning needles and needles can be adjusted. For example, Tongyu F007 three-needle five-thread interlock sewing machine can adjust the timing of the tensioning needle and the needle by adjusting the angle of the tensioning needle cam (F00710004) relative to the front section of the upper shaft (F00708001). The best time to cooperate is when the right machine needle enters the tensioning loop after the needle descends, the tensioning needle starts to move to the right.
The swing amplitude of the stretched needle must be ensured: when the stretched needle swings to the rightmost limit position, it can hook the stretched needle thread, and when the stretched needle swings to the leftmost position, the distance from the tip of the stretched needle to the left needle is 4.5-5.5mm.
The installation height of the stretched needle should be as high as possible, but the gap between the top of the stretched needle and the bottom of the stretched needle thread board should enable the stretched needle thread to pass smoothly.
The installation height of the tensioning needle thread board should be such that when the needle rises to the highest point, the tensioning thread smoothly slides under the right needle to the back of the right needle point (away from the operator side) so that the right needle is very Pin the stretched thread easily.
When the tip of the stretched needle swings to the front of the left needle, the gap between the left machine needle and the tip of the stretched needle should be 0.5-0.8mm.
Coordination of feeding action
The accurate feeding action of the interlock sewing machine can reduce the probability of stitch skipping. The main aspects of the machine that affect the feeding action are closely related to the height of the feeding dog, the pressure of the presser foot, the differential feeding, the stitch density, and the speed of use.
The main theory that puts forward this is: the stability of the triangular thread loop on the back of the looper depends on the stability of the cloth feeding action and the correct coordination of the thread take-up cam. If the feeding action is unstable, the triangular thread loop will be deformed or large and small so that the needle cannot enter the triangular thread loop.
The principle to be mastered when adjusting the height of the feed dog is that when the feed action is completed, the feed dog must completely return from under the needle plate, and no movement that causes the sewing material to retreat is allowed.
The presser foot pressure should ensure that the sewing material does not slip to the operator's side.
When the sewing material with large elasticity or the force of the operator pulling the sewing material into the arms is too large, the differential feeding amount should be increased.
The small stitch length of the triangle loop is also small, so the density should be appropriate, and if possible, it should be large rather than small.
Too fast will cause the sewing material to float or not be pressed by the presser foot instantly, which will affect the stability of the thread loop.
