| 摘要 |
<p>A sewing machine is equipped with a needle thread tensioning device which has two gripping discs mounted on a pin. The gripping discs are connected via a spring mechanism with two adjusting members on the same axis capable of movement relative to one another, of which at least one is mounted on a threaded section of the pin. In addition, the tensioning device has a mechanism for occasional suspension of the effect of the spring. With the tensioning device, in spite of the common mounting of both the adjusting members on the same pin, two tensions of varying degrees, a main tension and an auxiliary tension, can be adjusted and transmitted to the needle thread independently of one another and quickly switched one for the other. For this purpose, the two adjusting members are designed as inner and outer parts and separated from one another by a stationary support placed between the inner and the outer part. Each of these adjusting members is associated with a spring, a release disc and a mechanism for graduated release of the thread tension.</p> |
