Break is the most commonly encountered trouble sewing, and stitching quality does not comply, the machine improperly adjusted, over the line there is a sharp mouth parts, methods of operation problems, inadequate cooling machine needles, etc., will result in disconnection. When using the lock stitch sewing machine products uneven thickness encountered disconnection troubleshooting, in addition to analyzing all these reasons one by one to consider, we must also pay attention to the two hook line break caused.

Sewing machine industry is well known, due to the need to assign the action cycle design, the lock stitch sewing machine bobbin on the shaft and the gear ratio of 1: 2. That revolution of the shaft, the hook shaft to turn two weeks. Therefore, in the sewing process, machine needle prick feed once every rotation of the hook for two weeks, one week to complete the hook-wire loop extending the coverage of the action, a week idling, if the hook hooked noodles every week, that machine needle feed once, spin shuttle hook line twice, then bound with retractable side lines of conflict, resulting in the suture snapped phenomenon. This happens when sewn seam uneven thickness of the material is likely to occur: the reason was the formation process of lock stitch about:

1, the lock stitch formation process outlined

Lock stitch from side line and the bottom line are intertwined in the seam compound and composition. When the sewing machine, needle lead with a surface line through sewing materials, after reaching the lower limit position, elevate: Because there suture between the friction material and sewing, so the thread synchronization upgrade failed random needle, but stranded in the sewing material below, under the action of elastic expansion to both sides of the needle, forming a ring.

Then, the rotary hook tip reaches the needle in place during exercise, through the ring from the surface to the line, and continue to rotary motion, the hooked wire loop continues to expand. Raozhi after its radius, like skipping a line that jumps over the expansion of the ring.

Further down the wiper action is to close the line, feed dog feeding to make these actions have enough time to proceed smoothly, the hook is still the original speed rotation, but no hook line, just idling around. Since the closing line of action wiper, originally Hook expand and jumped over the side line ring shrinks rapidly, until the spin Haloxylon mind leads to sew the bottom line traction compound to form an intertwined.

After the needle reaches the upper limit position again when down barbed wire material, sewing machine again and again, repeat the above action process, resulting in the formation of continuous sewing materials on a regular lock stitch.

2, hook line time difference when sewing material thickness changes

A key element of the adjustment of the sewing machine is adjusted so-called hook-line time, the usual adjusting the standard is: When the needle dropped to the lowest position, when upward 2.2mm, shuttle needle tip reaches the center line from the pinhole edge 2mm. Of course, this is not immutable. Because the purpose of adjusting the essence of time hook line is hooked to the shuttle tip surface lines and the formation of a stable full of the best lines ring, thereby avoiding jumper phenomenon. Since sewing thin material is generally used is thin, soft suture itself, and sewing materials friction is small, but when sewing thick material in general use thicker lines, suture itself more stiffness, friction and sewing materials force, therefore, is not the same thickness of sewing materials, the best line of suture loop formation time is different, this time for adjustment hook line flexibility depending on the circumstances in order to get a good sewing results.

Experienced sewing machine repairman, operators know that when sewing thin material, hook tip to adjust quickly; when sewing thick material, hook tip to adjust slowly. Its reason is not hard to understand.

When sewing thin material, thread thin and soft, slightly raised from the needle under extreme positions, margin out of both sides of the suture needle will be swelling to form a wire loop. Further, since the friction is small stitch sewing material, the needle continues to move upward, the randomness of the suture material and sewing the relative positional relationship of the large soft combined with suture, wire loop is easy to deflect, it becomes difficult to maintain stability. Therefore, the hook tip relative to the movement of the needle slightly ahead of the adjustment will help improve the reliability of the hook lines.

On the contrary, when sewing thick material, the material is thick and stiff joints, machine needle lift by the lower limit position is high in order to form a full line ring. Also, the seam friction material and stitching large, coupled with relatively coarse sewing materials, even if the machine needle lift higher margin sutures out more wire loop will not deflect, still remain stable. Therefore, the hook tip relative to the movement of the needle up too late to prevent some more beneficial jumper.

3, the hook type and the role of the moon circle

After sewing needs according to the time line will hook a good tune, sutures bypass bobbin emerge from the time the hook will simultaneously determined. When sewing thick material, spin Haloxylon needle tip relative to the late adjustments, wire rings emerge from the hook in the time it late, when coupled with the largest line of sewing thick material to be less than the line, hook tip idling Week prolapse is generally not caught again line rings. But when sewing thin material, hook tip relative to the needle ahead adjustments, wire rings emerge from the time the hook is often earlier than the tip of the needle shuttle centerline time in idle weeks arrive, combined with less consumption of line when sewing thin material, I lines are more likely to occur in the idle weeks hook tip hooked again just emerge from the bobbin thread loop phenomenon, there is not the normal two hook lines.

When the hook normal hook line, wiper positive actinomycetes stage, the line rings emerge from the hook after the wiper quickly began closing lines. If the two hook lines appear, then bound and closing lines wiper conflict, it will definitely lead to breakage.

In order to avoid double hook line, the hook has taken effective measures to structural design. Compare seam thick and thin seam sewing machine bobbin can be found, either longitudinal horizontal shuttle, shuttle horizontal level or vertical rotary hook, construct its moon circles there is a clear difference.

Thick seam sewing machine bobbin moon circle only play a role of bile duct to form the shuttle, the end of the short flat. This is conducive to the thick line earlier when sewing thick material released from the hook, and as soon as the line was closed wiper action to pull dragged seam compound.

Stitch sewing machine bobbin thin circle of the moon is not the case, it was the tail end of the shape, length is longer, gradually shrink. Thin sewing machine bobbin moon circle only to play a role of bile duct formation shuttle, which is also responsible for guiding the tail end off-line duties, to observe can be found sewing thin material of the upper thread loop from the hook prolapse process, first turning circle around the moon on its tail, and then continue to rotate the hook in the process of gradually tapered from the tail slide was prolapse. Because the moon circle corner tip of the tail to the tip position has been delayed after the shuttle, so from the moon circles the wire loop end of the prolapse is in any case would not have been caught in the hook tip. Thus, it is reliably avoided the two hook-line. If no matter how to adjust, noodles always close well, the opposite occurs sewing materials floating line, you should check to see if the moon circle inappropriate, it is best to put the trailing edge of the moon short flat ring (polished also available) try.