Tape transport apparatus

A tape transport apparatus having

• a tape driving capstan which is rotatably mounted on a fixed shaft and has a resiliently deformable peripheral portion,
• means for driving said capstan,
• a take-up pack and a supply pack each mounted for rotation on a respective shaft,
• means mounting said packs for movement towards and from said capstan,
• contact pressure generating means for biasing said shafts towards said capstan so that the outermost tape turn of each tape pack is drivingly contacted by the capstan, said pressure generating means including braking means for varying the bias,
• said braking means comprising a friction brake disc mounted on the capstan shaft for rotation with the capstan, and generally disc-shaped brake elements unidirectionally coupled to the respective shafts carrying said tape packs, said friction brake disc being disposed for eccentric cooperation with said generally disc-shaped brake elements to be driven with slip by said brake elements, whereby the braking power of said braking means is utilized to drive said capstan, and
• said braking elements being disposed relatively to said friction brake disc so that the braking force produced depends on the momentary diameter of the respective tape pack.

A method for generating a constant tape tension in a tape transport apparatus having

• a tape driving capstan which is rotatably mounted on a fixed shaft and has a resiliently deformable peripheral portion,
• means for driving said capstan,
• a take-up pack and a supply pack each mounted for rotation on a respective shaft,
• means mounting said packs for movement towards and from said capstan,
• contact pressure generating means for biasing said shafts towards said capstan so that the outermost tape turn of each tape pack is drivingly contacted by the capstan, said pressure generating means including braking means for varying the bias,
• said braking means comprising brake elements on the shafts carrying said tape packs and at least one relatively stationary magnetic system;
• said method comprising varying the braking torque in dependence on the momentary diameter of the respective tape pack so as to produce a predetermined tape tension and maintaining said tension substantially constant.

A method for generating a constant tape tension in a tape transport apparatus

• a tape-driving capstan which is rotatably mounted on a fixed shaft and has a resiliently deformable peripheral portion,
• a take-up pack and a supply pack each mounted for rotation on a respective shaft,
• contact pressure generating means for biasing said shafts towards said capstan so that the outermost tape turn of each tape pack is drivingly contacted by the capstan, said pressure generating means including braking means for varying the bias,
• said braking means comprising brake discs on the shafts carrying said tape packs and at least one relatively stationary magnetic system;
• said method comprising:
• during acceleration from zero up to a desired speed, applying a larger braking torque to the brake disc associated with the tape pack having the smaller diameter,
• during tape transport operation at nominal speed, applying a larger braking torque to the brake disc associated with the supply pack, so as to produce a predetermined tape tension and maintaining said tension substantially constant, and
• during deceleration from nominal speed to zero, applying a larger braking torque to the brake disc associated with the tape pack having the larger diameter.