Abstract: In a sewing machine having a needle bar jogging frame in which a needle bar which can be driven with a reciprocating motion in its longitudinal direction is mounted, the jogging frame is in the form of a member of a parallel four-bar linkage. For this purpose the frame is mounted by way of a guide lever and a lever so as to be movable parallel to itself in the heat of the sewing machine. The lever and the guide lever are designed equal in length and arranged parallel to one another. This development creates a simply constructed jogging frame so that the needle bar and thus also the needle are always moved or displaced parallel to themselves in the jogging plane of the jogging frame, irrespective of the stitch length and irrespective of whether the sewing direction is forward or backward to produce lock stitches.

Abstract: A double chain stitch sewing machine having a feeding device with a feed dog oscillatingly movable in and opposite to the feeding direction for producing a relative movement between a workpiece and the sewing machine. It has a needle reciprocatingly driven by a crank mechanism, at which the feeding mechanism also imparts synchronous jogging movements to the needle in order to generate a needle feed movement. The reciprocatingly and joggingly driven needle cooperates with a looper oscillatingly driven by a looper drive mechanism in parallel with the feeding direction. The looper drive mechanism is formed as a six-bar-linkage-mechanism provided at the input with a stationary pivot and at the output with a stationary pivot and provided with an intermediate pivot.