Method of electrically perforating a planar web
US4207458A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 18, 1978 |
| Grant date | Jun 10, 1980 |
| Priority date | — |
| Expiry date | Oct 18, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T83/0414
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A web is electrically perforated at high hole density by applying alternating-current voltage across an electrode pair facing the web while pressurized gas is supplied to the electrode gap. Voltage amplitude level and gas flow level are selected to provide for the striking of multiple arcs per half-cycle, thereby enabling reduction in spacing between adjacent perforations in the web. Perforation practice involving preselection of cigarette filter tipping paper based on chemical composition of the paper is also disclosed as is apparatus for use in implementing the described practices, wherein electrode support members have gas flow conduits formed integrally therewith and wherein webs are taken up by a capstan drive unit resiliently biased into engagement with a web take-up roll.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.