On 3/12/2016 12:36 AM, Look165 wrote:
One (the small one) is the motor capstan.

The other one is the pressure capstan.

Direction is given by the rotation of the first one and speed is
servo-controlled.

Generally there is a lever for the tension of the tape.


DaveC a écrit :
Oh, smarter-than-I people,

http://imgur.com/WPEoOu1

The 2 belt-drive capstan flywheels in an auto-reverse cassette
mechanism are
different sizes. (Motor drive pulley will be in the small loop end of the
belt in illustration above.)

How does that result in the same tape speed in both directions?

Confused...


The tape speed is controlled by the motor drive capstan.
Doesn't matter which way the tape is going.
The two flywheels are different sizes, but have the same
rotation speed. That causes the belt to
stretch on one side and compress on the other to account for
the different sizes. That belt tension creates the tape tension.
That's independent of the direction of the rotation.
Tape speed across the heads is always controlled by the drive motor.