Thread take-up lever

The main body and core of the sewing equipment, take the flat sewing machine as an example, no matter how complex and precise its mechanism is, as long as the sewing material is sewn with needles and threads, it is indispensable to the joint movement of the four basic mechanisms: the needle bar mechanism, the hooking mechanism, the picking mechanism, and the feeding mechanism.

Among the four basic mechanisms, the one that conveys, recovers, and tightens the needle and thread is called the thread-picking mechanism. The thread take-up lever is responsible for collecting and releasing the thread in each sewing cycle and cooperating with the fabric feeding mechanism to complete the formation of sewing stitches. The thread-picking spring, thread clamp, and slow thread hook are all subordinate to the thread-picking mechanism, and proper adjustment of tension and thread take-up accessories is an important condition for maintaining a good stitch.
The working characteristic of the thread take-up lever is the up-and-down movement of the thread take-up lever hole. When the thread take-up lever is moving downward, it is to supply thread to the descending needle, and secondly, it is to supply thread to the rotary hook when the rotary hook is hooked on the thread until the thread is wrapped around the bobbin holder and then finished. When the thread take-up lever moves upward, it again assumes the responsibility of dislodging the facings from the bobbin holder drawing the formed stitch in the sewing material tightly to form a firm stitch, and withdrawing the facings from the thread mass in preparation for the formation of the next stitch.

1. Cam picking mechanism. A mechanism in which the thread take-up lever is driven by a cam.
2. Rod picking mechanism. A mechanism in which the thread take-up lever is moved by a four-link mechanism. The thread take-up lever is the connecting rod of the four-link mechanism.
3. Slide rod picking mechanism. The crank slide lever mechanism drives the thread take-up lever movement of the mechanism. The thread take-up lever is the guide rod of the four-link mechanism.
4. Rotary wire picking mechanism. One or two are equipped with picking pins of the garden plate or other shapes of the components, to rotate the movement of the picking movement of the mechanism.
5. Needle bar thread picking mechanism. Fixed in the needle bar over the line or clip the line device, or directly fixed in the needle bar thread take-up lever mechanism.

In the industrial sewing machine is generally used in the rod picking line, needle bar picking line is most common. There are two types of thread picking, one is to tighten the previous loop before the needle is fed into the machine, and the other is to tighten it when the needle is withdrawn by using the tension device of the thread take-up device. The first method is used on overlock sewing machines or interlock sewing machines (including double-thread chainstitch sewing machines), and the second method is used on lockstitch sewing machines. The thread required for the needle to enter the thread for the second time comes from two sources, one obtained during the tightening of the previous stitch and the other taken from the bobbin after overcoming the pressure of the tension regulator. In general, the stroke and trajectory of the thread take-up lever are relatively fixed. Due to its subordinate position, it is determined that the relevant dimensions of the mechanism are unlikely to be adjusted and should be manufactured and installed in strict accordance with the positioning requirements.

The thread-picking mechanism of the flat sewing machine was first designed with a cam mechanism, linkage mechanism, etc. Since each rod of the linkage mechanism is connected with a low vice, it has many advantages, especially to make the thread breakage rate of the cotton thread lower, therefore, the linkage thread picking mechanism is adopted in all the industrial flat sewing machines at present. At present, the industrial sewing machine's four-rod thread-picking mechanism, role is mainly to prevent the cloth-feeding teeth will sewing material forward into the elongated thread section and relax the thread, so that the needle in the puncture of the sewing material to reduce the interference force, according to the conveyor and tighten the sewing thread to complete the stitch with the amount of appropriate adjustment of the amount of thread to ensure that the needle puncture force action of the correct position.