| 摘要 |
PURPOSE:To prevent abrupt change in the tape tension when braking the tape reel which is rotating at high speed, by making an arrangement that the braking torque of the 1st motor will be reduced from a prescribed value and, moreover, maintained almost constantly after the tape reel is stopped. CONSTITUTION:When the condition where a signal FF is supplied to a terminal 22 is switched to the STILL mode, a brake-ON command signal BRK is supplied to a terminal 24 and switches 16 and 17 are closed. Therefore, a voltage VT1 is obtained and a 120g.cm braking torque is given to a motor 9. On the other hand, a pulse obtained from a frequency generator (FG) 10 triggers monostable mutivibrators 12 one after another and closes a switch 14 through an AND gate 18, and a 700g.cm braking torque is given to a motor 8. When the frequency of the FG pulse is lowered due to the decrease in the tape speed, the output of the monostable multivibrators 12 is inversed and the torque of the motor 8 is gradually reduced to 120g.cm at the time of tape stopping. When the monostable multi-vibrators 12 are triggered by the last FG pulse, the signal BRK disappers and motors 8 and 9 are held with a tape tension of about 30g. |
