Variable torque device for maintaining constant web tension
US7130571B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 14, 2004 |
| Grant date | Oct 31, 2006 |
| Priority date | — |
| Expiry date | May 9, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/2093
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A variable torque device for maintaining constant tension in a web of material as the web is unwound from a supply roll. The variable torque device includes a lead screw attached to the shaft of the supply roll via an appropriate gear ratio. A coil spring is located between a hub on the lead screw and a set of rings and friction pads. As the lead screw rotates, the hub translates, thus changing the displacement of the coil spring, which in turn changes the loading of the rings and friction pads. With a full supply roll the coil spring is compressed so as to create an amount of torque to create the desired web tension. As the supply roll unwinds, the rotation of the lead screw translates the hub to expand the coil spring, reducing the torque and maintaining the web tension constant.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.