different diameters of the work piece opening application_number US 46966190 A description referring now to fig1 there is shown a sewing machine 1 mounted on table top 2 which is supported by a frame 3 the sewing machine has a motor drive and brake 4 having a control box 5 for controlling the working cycle for the sewing machine which is flange mounted onto the frame 3 the table top carries a control panel 6 for entering sewing specific data for example the operating speed and for switching on the sewing machine which is driven by the motor drive 4 by means of a belt 7 the sewing machine has a workpiece feed device 8 which conveys a circular workpiece 9 as shown in fig1 or a flat workpiece 10 as shown in fig5 the sewing machine has a needle bar 11 driven by a suitable device in a reciprocating manner and a needle head 12 which carries a needle 13 the sewing machine 1 has a reciprocating presser bar 14 disposed next to the needle bar 11 and has a presser foot 15 as shown in fig3 and 6 the presser foot 15 carries part of a marker 16 which applies a mark 17 to the workpiece 9 or 10 as shown in fig3 the sewing machine 1 has a sensor 18 which is disposed in a predetermined relationship a relative to the marker 16 with reference to fig1 and 3 the sensor 18 is electrically connected by a control line 19 to the control box.