To adjust the tension of the bobbin thread is a special trimmer screw on the Shuttle. Presser foot pressure on the fabric for serious sewing machine is important to the existence of opportunities to adjust foot pressure on the material. To obtain high-quality lines and a given stitch length for delicate fabrics necessary to provide high pressure, and for thick pressure must be reduced. In the electromechanical machines, pressure is provided by a special spring. In some machines provide special control efforts spring and, consequently, foot pressure on the fabric. In complex machines with computer control sometimes provides automatic pressure adjustment or special monitoring its persistence. On the possibility of flash very thick material designers of the car also took care of – the maximum lift feet up to 12 mm. Drive, power and effort to puncture speed adjustment and control of sewing.
The mechanism of the sewing machine shown in propelled by an electric motor. In the low-cost electromechanical machines commonly used motor for ac 220V. More expensive cars are equipped with low-voltage dc motors. The most complex machines can contain up to 10 motors. In cars with ac motor force puncture depends on the speed of sewing, that is certainly not convenient. That the machine is easy to cope with the tissues of any density and thickness, electronics should provide the maximum force with which the needle should pierce the fabric, regardless of engine speed. To do this, design of the machine include an automatic controller efforts of the puncture needle.