Patent ID: 8286569

Claim:
A sewing machine comprising: a needle bar capable of supporting a needle and capable of vertical reciprocal movement; a needle bar vertical moving mechanism bringing the needle bar into the vertical reciprocal movement; a needle bar swing mechanism causing the needle bar to swing in a lateral direction relative to a longitudinal direction along which a feed dog operates for straight stitch; and a control portion controlling operations of the needle bar vertical moving mechanism and the needle bar swing mechanism for adjusting a swing amount of the needle bar which is brought into a swing movement in the lateral direction by the needle bar swing mechanism during a free motion sewing mode; and an upper thread tension adjusting mechanism for providing a tension on an upper thread which extends to the needle from an upper thread supply source, wherein during the free motion sewing mode in a case where a signal for stopping the free motion sewing is outputted, the control portion causes the upper thread tension adjusting mechanism to provide the tension on the upper thread unless a time durationÎ”T elapses after the outputting of the signal for stopping the free motion sewing and causes the upper thread tension adjusting mechanism to loosen the tension on the upper thread if the time durationÎ”T elapses after the outputting of the signal for stopping the free motion sewing.