公开(公告)号：DE3380779D1

公开(公告)日：1989-11-30

申请号：DE3380779

申请日：1983-08-23

Applicant: IBM

Inventor： DANIELSEN KENNETH DANIEL ,  WINARSKI DANIEL JAMES

IPC: G01L5/00 ,  G01B21/06 ,  G11B15/02 ,  G11B27/13 ,  G11B27/17 ,  G11B27/10

Abstract: The amount of tape wound on the hub of a reel can be determined by the tape drive by using a force/acceleration relationship. An electrical power which provides a certain torque to the motor (2) is applied to the reel drive. The torque imparts a fixed rotational displacement over a fixed period of time. The rotational displacement is measured by a tachometer (7). The angular acceleration of different inertias results in different rotational displacement over the set period of time which can be used to indicate the amount of tape on the reel since the inertia of the other items, the motor, the clutch and the hub, remains the same.