Ribbon tension control
US4573645A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 23, 1983 |
| Grant date | Mar 4, 1986 |
| Priority date | — |
| Expiry date | Nov 23, 2003 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB65H23/1806
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A ribbon tension control for controlling the tension of ribbon traveling between a rotating supply spool and a rotating take-up spool varies the amount of braking torque applied to the supply spool to hold ribbon tension constant as the distribution of ribbon between the spools changes. A generator rotationally coupled to the supply spool produces braking torque to resist the rotation of the spool when the generator windings are electrically loaded. The loading of the generator is controlled by processing feedback signals emitted by the generator to provide periodic load switching signals. Processing of the feedback signal is accomplished in the exemplary embodiment by a drag lookup table which is addressed by the feedback signal. The drag lookup table produces a duty cycle value which is used to determine the duty cycle of the switching signal, which, in turn, controls the electrical loading of the generator. Because electrical loading of the generator at the switching signal rate modulates the feedback signal which it emits, the period of the switching signal is sufficiently different from that of the feedback signal to permit separation of the feedback signal from the switching …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.