| 摘要 |
<p>PURPOSE:To secure a constant level of back tension for a tape, by applying the rotary torque produced from a viscid coupling part to a brake lever when a supply reel drive disk is turning and accordingly controlling the press-contact force of a brake shoe to the supply reel drive disk. CONSTITUTION:A supply reel drive disk 21, a rotary shaft 20 and a brake drum 22 are turned all together toward the direction marked with an arrow B. Accordingly a viscid coupling plate 31 is going to turn toward an arrow A along with the disk 21 by the viscidity of a viscid plate 32. However, the rotation of the plate 31 is prevented since a pin 42 of the plate 31 engages with an arm 41 of a brake lever 37. As a result, the disk 21 has a relative rotation to the plate 31, and the rotary torque proportional to the speed of rotation of the disk 21 is produced in the dirction of the arrow B by the viscidity of the plate 32. Accordingly the rotary torque affects the plate 31, and this torque is conveyed to the arm 41 of the lever 37. Thus the press-contact force of a brake shoe 39 to be applied to a brake drum 22 is reduced in accordance with the speed of rotation of the disk 21.</p> |
