| 摘要 |
<p>PURPOSE:To lessen the variation in the beginning end position of a projection to prevent vibration of a tape on a tape detaching side by executing chamfering at the top end of a stationary drum, the projection described above and a turning surface by continuous cutting with a single blade. CONSTITUTION:The turning surface 12 is formed on the stationary drum 11 of a diameter slightly smaller than the diameter of a rotary drum provided with a magnetic head and the projection 13 for preventing tape vibration is formed in a tape contact starting position or tape detaching position by cutting with the blade 10. This blade 10 is provided with a guide surface cutting part 14 for cutting the surface 12 and the outer peripheral surface of the projection 13, a slope cutting part 16 for cutting a slope 15 arriving at the surface 12 from the projection 13 and a chamfer cutting part 18 for cutting the chamfering part 17 at the end of the drum 11. The blade 10 cuts the chamfering part 17 first, then the outer periphery at a size of d+2delta parallel with a helical lead 19 and cuts the surface 12 at a size of (d) after cutting the prescribed size in an axial direction. As a result, the variation in the beginning end position of the projection 13 is lessened and the vibration of the tape is stably prevented.</p> |
