| 摘要 |
<p>PURPOSE:To set a web loading speed at an optimum state by controlling an arm driving motor so that an output pulse obtained from a tachometer disk may be constantly maintained. CONSTITUTION:At a rotational position that corresponds to the threader arm 3 of the tachometer disk 13, slits 15 whose size of width and spacing are differenciated are provided, and the change of a pulse cycle generated from the slits is used as the information of a revolving speed. The difference of a cycle length between the output pulse of the tachometer disk 13 and a reference pulse is sent to a driving circuit 23 of a threader motor, and the threader motor 12 is revolved so that the output pulse and the reference pulse may be synchronized according to the difference of the cycle length. Then, the threader motor 12 is controlled in order for the cycle to be constant. Thus, when the threader arm 3 is revolving, the speed which is optimum at an objective position is obtained.</p> |
