Patent attributes
A sewing machine including a needle being supplied with an upper thread, a loop taker which accommodates a bobbin for a bottom thread, and a drive unit, which forces the needle to perform a reciprocating movement. The needle, during its movement and in cooperation with the loop taker, executes a stitch on a sewing material being advanced between the upper thread and the bottom thread. A take-up lever, for each stitch, pulls tight a knot being formed in the sewing material by the upper thread and the bottom thread in cooperation. The sewing machine further includes a thread transfer member supplying the needle with an upper thread with either a thread portioner or a friction braking assembly for friction braking of the upper thread. A switch switches between thread supply with the thread portioner or with the friction braking assembly. A control unit controls the thread supply from the thread portioner or, alternatively, controls the friction braking assembly.
