Difficult-to-feed materials like e.g. microfibre are perfectly fed by the top puller feed of the lockstitch machine 273, even at maximum speed. The feeding speed of the top puller feed can be easily adjusted by a dial - separate from the bottom feed. Due to the minor advance of the puller feed the material is slightly stretched and absolutely tension-free seams are produced. If required, the puller can be swivelled out of the sewing area so that the clearance of the 273 is equal to that of the 271/272.