| 摘要 |
<p>The invention makes it possible to rotate an arm shaft of a sewing machine without a mechanical clutch between the hard wheel (10) and the arm shaft (23). The position of the hand wheel which previously was very dependent on the mechanical system, can now be chosen so that the best possible ergonometry is obtained. An electrical sensor (16, 17) of the rotation of the hand wheel and another sensor (26, 27) of the movement of the arm shaft are compared in an electronic unit (41), and as long as there is a difference in the outputs of the sensors the electronic unit will cause driving of the sewing machine motor so that the difference will be zero. The movement of the hand wheel is thus repeated on the arm shaft.</p> |
