| 摘要 |
PURPOSE:To hold a difference in peripheral speed between both the capstans of a closed-loop double capstan drive system constant by bringing a belt into contact with one flywheel by providing a projection part, which has high belt-run restraint force, to the flywheel. CONSTITUTION:So that the peripheral speed of a down-side capstan 5 is about 0.1% higher than that of an up-side capstan 7, the diameters of corresponding flywheels 12 and 14 are determined while the diameter ratio of both the capstans 5 and 7 is considered in order to give tension to a magnetic tape 8 between both the capstans, thus obtaining contact force to a magnetic head 11. The up-side flywheel 14 is one-third as wide as a belt 13, and a part which meets the belt 13 has a flat annular projection part 17, an annular guard part 18 for preventing the belt 13 from falling off, and a recessed part 19 which never touches the belt 13 evne if the belt 13 bends. Consequently, even if the center of the belt 13 deviates from that of the flywheel 14, the belt 13 touches only the flat projection part 17 and never varies in running radius. |
