Sewing machine with apparatus for sewing a curved seam

A sewing machine, comprising:

• a sewing needle:
• first means for transporting material to be sewn, the transporting means having a transporter acting on one side of the material to be sewn and a presser foot which can be placed on the other side of the material to be sewn in the effective area of the transporter;
• second means for transporting the material to be sewn which can be switched from an ineffective condition into an effective condition and vice versa;
• said second transporting means including a transport element rotatable about an axis parallel to and at a distance from the longitudinal axis of the sewing needle which in the effective condition takes hold of the material to be sewn at a distance from and adjacent the first transporting means by being placed on the material on the same side as the pressure foot and rotates about the rotational axis of the transport element;
• and
• a control device, which, during the sewing of a circular curved seam to be produced with the aid of the second transport device, holds the first transport device in an ineffective condition and holds the second transport device in an effective condition, and for seams that may be produced in a different shape, holds the first transport device in an effective condition and holds the second transport device in an ineffective condition.