Research on Electronic Thread Nipper for Computerized Lockstitch Sewing Machines

With rapid economic development and continuous improvement in living standards, people have higher demands for garment quality and grades. Consequently, the performance requirements for sewing equipment closely related to garment production have naturally risen synchronously. Along with the advancement of sewing machine electronics integration technology, more and more sewing machine products incorporate automatic control functions, such as the commonly referred "three automations". Currently, various automatic control functions have been applied to different extents on sewing machines, especially lockstitch sewing machines. In garment manufacturing enterprises, the thread tails produced during sewing often need to be manually trimmed for aesthetic reasons, reducing production efficiency and increasing costs - a problem that plagues enterprises. The current solution adopted by sewing equipment manufacturers is to use automatic thread trimming. The electronic thread nipper, as a new mechanism, has not been widely promoted. After market research, it is believed that using an electronic thread nipper is far superior to using an automatic thread trimming electromagnet.

As the sewing machine needle moves from its highest position to the lowest and then rises a certain distance, it enters the rotary hook threading process, and the shuttle point begins to catch the thread. At this point, the electronic thread nipper needs to activate and grip the upper thread. The rotary hook cannot obtain thread from the thread take-up lever, so the thread required to wrap around the shuttle can only be pulled from the other end of the needle (i.e., the part of thread left at the needle end after the previous cutting). This pulls the previous thread tail under the fabric. Before the rotary hook threading process completes, the electronic thread nipper releases the thread in advance. At this point, the take-up lever has begun the thread recovery process, followed by the normal sewing stage.

Computerized lockstitch sewing machines have automatic thread trimming functions. After cutting the thread, a thread wiper mechanism brings the thread tail out from the fabric onto the top of the presser foot. This way, during the next sewing cycle, the thread tail gets hidden on the underside of the fabric. However, using automatic thread trimming may cause the following issues:

If the thread is caught under pressure from the presser foot, the large clamping force prevents the thread tail from being tucked under the fabric, leaving it exposed on top and requiring manual trimming.

The automatic thread trimmer itself has a complex structure with intricate transmission, posing a safety hazard of breaking the needle if improperly adjusted.

The thread trimmer only activates after the thread is cut and needle stops moving, with the entire action taking about 100ms. Many operators disable this function to pursue higher personal efficiency, also leaving thread tails on top requiring manual trimming.

During the thread trimming action driven by a spring, the strong impact force may cause accidents if the operator proceeds to the next step without waiting for completion.

Using an electronic thread nipper resolves these issues. At the start of the first stitch, the nipper performs the thread gripping action, offering the following advantages:

No impact on the sewing machine's original acceleration time, saving the time occupied by automatic trimming.

Simplification of thread trimmer mechanical components, reasonably reducing costs.

During sewing, even if the thread tail gets caught under the presser foot after trimming, it will be easily pulled under the fabric. Operators do not need to worry about the thread position.

The nipper electromagnet has a simple structure, low cost, and easy installation.

When the nipper grips the thread as the needle starts piercing the fabric, the remaining thread at the needle will shorten due to the needle's downward motion. At this point, the nipper releases, allowing normal sewing operation to reduce "bird nesting" for "clean stitching". Particularly after optimization of the nipper coordinating with the automatic presser foot lifter electromagnet, the stability of active thread retraction is greatly improved, reducing the stability requirements on the machine itself.

If you need to purchase lockstitch sewing machines, please contact us at sale@eagleco.cn.