| 摘要 |
<p>PURPOSE:To prevent the slip between a tape and a reel and to improve the tape feed performance by using a damping torque switch means which reduces the damping torque of a driving motor when a detecting means for winding diameter of a magnetic tape detects a winding diameter smaller than a prescribed level. CONSTITUTION:An input signal B is applied to flow an adverse super-power current to a closed circuit of a diode D1 a resistor R or a switch K a motor armature 20 a transistor TR-4 when a tape loop 12a moves down lower than a detecting position 11. Thus the damping force is produced to the power generation of a driving motor of a working file reel 2. Then the tape feed is decelerated and stopped. Then the loop 12a moves up again higher than the position 11 owing to the feed of a capstan 9 and turns on both TR-1 and TR-3. Thus the armature 20 is driven and the reel 2 is revolved clockwise to feed continuously a magnetic tape 5 into a vacuum column 7 until the loop 12a moves down lower than the position 11. Under such conditions, only the TR-4 is turned on. Thus the feed of the tape 5 is decelerated and stopped.</p> |
