| 摘要 |
PURPOSE:To detect and display the remaining amount of a magnetic tape by detecting the extent of displacement of a tension arm which turns to control the tension of the magnetic tape constant during a tape run. CONSTITUTION:The tension arm 22 has a projection part 22a engaging a spring 23 which supplies proper tension to the magnetic tape 7 and is provided with a back tension band 25 which winds up a payoff reel turntable 8a from the tip of an arm 24 that is turnable only counterclockwise. The tension arm 22 is turned gradually in a direction D according to a run of the tape, and the payoff reel is loaded to make the tape tension constant, so the extent of D-directional turning amount depends upon the weight of the magnetic tape 7a wound around the payoff reel 8; and the extent of displacement of the tension arm 22 is detected to grasp the remaining amount of the magnetic tape. Namely, the remaining amount of the tape is displayed on a display part 29 according to the rotation of a detection gear 26. |
