Method for making flat bottom plastic bag
US5102384A · kind A · utility
Inventors
Key dates
| Filing date | Sep 1, 1989 |
| Grant date | Apr 7, 1992 |
| Priority date | — |
| Expiry date | Sep 1, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S493/936
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A method is disclosed of constructing a flat bottom in a plastic film tube having an open upper end, a closed lower end formed by a transverse seal, forward and rearward sides and a pair of opposing pleated sides that interconnect the forward and rearward sides. The method includes the steps of releasably engaging a lower vacuum and a lower clamp with a transverse section of the rearward side of the tube to provisionally hold the transverse section. A lateral section of the forward side is gripped and raised by an upper vacuum and an upper clamp to expose a portion of the pleated sides such that first and second pockets are formed, respectively, in the sides. The sealed lower end is drawn toward the upper end to fold the tube along first and second transverse fold lines in the forward side, along a third transverse fold line in the transverse section of the rearward side, and along fourth and fifth fold lines, respectively, in the pleated sides such that the first and second pockets are located in the pleated sides, respectively between the first and third fold lines and the lower end of the bag. Pressure is applied to the tube to form creases along the first, third, fourth and fif…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.