Method and apparatus for gauging reel diameters in a reel-to-reel sheet material transport system

摘要

Method and apparatus are disclosed for determining the diameter of sheet material wound on a reel, and for setting the tension on sheet material as it is wound on the reel. According to one embodiment, the diameter of a take-up reel including sheet material wound thereon is determined from the angle of rotation or instantaneous angular speed of the take-up reel, and movement of the sheet material as obtained from rotation of a circular element such as a drive roller in a pinch roller drive system which rotates in proportional to sheet material movement. In another embodiment, the diameter of a reel in a reel-to-reel transport system is determined from the angles of rotation or instantaneous angular speeds of the supply and take-up reels, the total amount of sheet material in the system, and the packing factor of the sheet material rewound on the take-up reel. The diameter determination may then be used to set the torque of the drive motor for the take-up reel, and thereby the tension on the sheet material during winding.