A device for keeping a thread tightened and secured while weaving is provided. The thread is allowed to advance in order to make a stitch and further allows the thread to return to an original position so that it remains tensioned for the next stitch. The device is retractable so not only secures the thread but returns it so that it never loses tension. In addition, it has openings designed to allow resting a needle when not weaving.

A device for keeping a thread tightened and secured while weaving is provided. The thread is allowed to advance in order to make a stitch and further allows the thread to return to an original position so that it remains tensioned for the next stitch. The device is retractable so not only secures the thread but returns it so that it never loses tension. In addition, it has openings designed to allow resting a needle when not weaving.

A sewing-thread pre-stress device for a sewing machine includes: a sewing-thread support, a pre-stress supply member, an abutting member and a top cover. The sewing-thread support includes an accommodating groove with a groove bottom. The pre-stress supply member is made of elastic material, provided in the accommodating groove, and has a folding portion which has two extension portions with one end connected to two sides of the folding portion. The abutting member is disposed on the pre-stress supply member, and the two abutting portions abut against the abutting member. The top cover is disposed on the abutting member and fixed to the sewing-thread support to define a thread space between the top cover and the abutting member for allowing a sewing thread to be inserted therethrough. The member is elastic and V-shaped, therefore the elastic force change is relatively small, which can provide the sewing thread an appropriate tension.

A sewing-thread pre-stress device for a sewing machine includes: a sewing-thread support, a pre-stress supply member, an abutting member and a top cover. The sewing-thread support includes an accommodating groove with a groove bottom. The pre-stress supply member is made of elastic material, provided in the accommodating groove, and has a folding portion which has two extension portions with one end connected to two sides of the folding portion. The abutting member is disposed on the pre-stress supply member, and the two abutting portions abut against the abutting member. The top cover is disposed on the abutting member and fixed to the sewing-thread support to define a thread space between the top cover and the abutting member for allowing a sewing thread to be inserted therethrough. The member is elastic and V-shaped, therefore the elastic force change is relatively small, which can provide the sewing thread an appropriate tension.

A device for keeping a thread tightened and secured while weaving is provided. The thread is allowed to advance in order to make a stitch and further allows the thread to return to an original position so that it remains tensioned for the next stitch. The device is retractable so not only secures the thread but returns it so that it never loses tension. In addition, it has openings designed to allow resting a needle when not weaving.

A device for keeping a thread tightened and secured while weaving is provided. The thread is allowed to advance in order to make a stitch and further allows the thread to return to an original position so that it remains tensioned for the next stitch. The device is retractable so not only secures the thread but returns it so that it never loses tension. In addition, it has openings designed to allow resting a needle when not weaving.

The present disclosure discloses a thread tension adjusting device comprising a body, a tension rod, an elastic element and an adjusting knob. A thread passing eye for inputting a thread is arranged below the body. A tension wheel and a thread passing wheel are rotatably arranged on the body. An adjusting knob is used for adjusting a rotational speed of the tension wheel. The elastic element has one end connected to the body and another end connected to the tension rod. The thread tension adjusting device may ensure stability of tensioning and transmitting of the thread by cooperation between the tension rod and the tension wheel, and improve precision for thread tension adjusting by the adjusting knob. In addition, the thread tension adjusting device may monitor thread breakage by the tension detector, and ensure operating stability and safety of the thread tension adjusting device.