Respirators
US4417575A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 22, 1981 |
| Grant date | Nov 29, 1983 |
| Priority date | — |
| Expiry date | Jun 22, 2001 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA41D13/113
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
The present invention relates to a filtering facepiece made from flexible filtering sheet material. The facepiece is made from a flat pocket 100 of filtering sheet material having opposed side walls 105 and 106, a generally tapering shape with an open end 104 at the larger end and a closed end 101 at the smaller end. The edge of the pocket at the closed end is outwardly bowed, e.g. defined by intersecting straight lines and/or curved lines, and the closed end is provided with fold lines 107 defining a surface which is folded inwardly of the closed end of the pocket to define a generally conical inwardly extending recess 108 for rigidifying the pocket against collapse against the face of the wearer on inhalation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.