Method and apparatus for registration of a seal on a plastic bag
US5587032A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 12, 1994 |
| Grant date | Dec 24, 1996 |
| Priority date | — |
| Expiry date | Aug 12, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB31B2160/10
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A plastic bag making machine includes a cylindrical drum with a variable diameter. A plurality of seal bars define the circumference of the drum, and are substantially parallel to the drum's rotational axis. The bags are made from a plastic film with registration marks that are detected by a detector disposed near the film. A detector also detects each revolution of the drum and an encoder provides signals indicative of the position of the film. A controller determines the distance phase of the registration marks and the rum size error. The drum diameter is adjusted in response to an output of the controller in such a way as to correct for both the initial drum size error, the initial phase error, and the phase error accumulated while the drum diameter is being corrected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.