Sewing machine, especially cyclic or circulatory sewing machine

摘要

The subject of the invention is a sewing machine which is equipped with a workpiece holding-down device. The workpiece holding-down device comprises a holding-down arm (2) which is movable between an upper position and a lower position and which is usually prestressed into the upper position, an auxiliary workpiece holding-down part (19) which is movable between an upper position and a lower position in synchronism with the rotation of the main shaft and which is usually prestressed into the upper position, a disengageable connecting device which is arranged between the main shaft and the auxiliary holding-down part, an electromagnetic device (5) which can be energised for the start of the work of the sewing machine and deenergised at the end of the formation of a seam, and a working device (5a to 16) which, in response to the energisation of the electromagnetic device, takes effect in order to apply an operating force to the auxiliary holding-down part (19) and the holding-down arm (2), and which cancels the operating force in response to the deenergisation of the electromagnetic device. <IMAGE>