| 摘要 |
A device for connecting the balance wheel of a sewing machine with the main shaft in which a metallic disc within a cylindrical-surface of the balance wheel is rigidly connected with the main shaft, a U-shaped flexible element connected in its lower part with said disc, a U-shaped spring within the flexible element and secured thereto by two tongues engaging two slots on the upper end of the arms of the flexible element and an elliptically shaped cam inside the flexible element and spring so that in one position the cam forces the arms against the cylindrical surface of the balance wheel thereby engaging the main shaft with the balance wheel and in the other position the arms are spaced from the cylindrical surface of the balance wheel as a result of the action of the spring so that the main shaft is disengaged from the balance wheel. The positions of the cam are delimited by the opposite ends of a circumferential groove on the disc and engaged by a tooth provided on the front part of the cam. |
