US 2787264 A
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Q April 2, 1957 B. THIEBAULT ET AL MASK FOR FILTERING AIR CONTAINING FINE PARTICLES SUCH AS DUST Filed Feb. 3, 1954 United States Patent MASK FOR FILTERING AIR CONTAINING FINE PARTICLES SUCH AS DUST Bernard Thiebault, Montmonrency, and Gilles Gohin, Luzarclles, France, assignors to Societe dExploitation des Plastiques, Gemevilliers, France, a French company Application February 3, 1954, Serial No. 407,956
Claims priority, application France February 7, 1953 1 Claim. (Cl. 128-146) This invention relates to masks for filtering air containing fine particles, particularly air containing dust.
In particular the invention relates to masks of the kind which comprise filtering material shaped in the form of a pouch, the lower portion of the pouch bearing under the chin of the user whilst the upper portion bears against the base or root of the users nose.
In order to be effective, such a mask must fit perfectly against the users face, and movements of the jaw must not result in the admission of unfiltered air. One object of the invention is to provide a mask of the kind specified which substantially meets this requirement.
To this end the pouch filtering material is made from a sheet of slightly elastic microporous plastic material, the edges of the opening of the pouch formed thereby being bent over on themselves in such a manner as to form a thick elastic rim which adapts itself to the movements of the jaw, thus maintaining contact with the skin as the latter moves.
It is most diflicult to maintain contact between the edges of the mask and the skin at the root of the nose, as these edges tend to extend in a straight line from the bridge of the nose to the cheek without following exactly the natural curve of the junction between the nose and the check, which junction may vary very considerably from one user to another. We have appreciated, therefore, the necessity for the edge of the pouch in this zone to have high elasticity.
This result is very simply achieved in accordance with the invention, by freeing appropriate parts of the rim so that the freed parts expand elastically in accordance with a deformable curve corresponding substantially to the curve of the junction between the nose and the cheek.
The invention will be more readily understood by reference to one embodiment thereof, which is illustrated by way of example only, in the accompanying drawings in which:
Figure 1 is a view of the mask in perspective, in the position of use,
2,787,264 Patented Apr. 2, 1957 "ice Figures 2 and 3 are sections on the lines 11-11 and lIl -lII of Figure 1, and
Figure 4 is a sectional elevation on the line IV--IV of Figure 2.
The mask illustrated consists of a pouch formed from a sheet of microporous elastic material which is cut to an appropriate shape, is folded over on itself along the lower line A and is assembled by stitching or sticking along the curved line B. The user introduces the lower portion of his face into the opening of this pouch in such a manner that the edges of the latter bear against his chin and the base of his nose. The mask is held in position by an elastic band 1 secured to the opposite outer side walls of the pouch at 2 and 2'.
In accordance with the invention, the rim of the opening of the pouch comprises a bead 3 formed by folding over the free edge inwardly on itself and stitching or sticking it along the line 4. The bead 3, on being compressed against the skin as indicated at a and a, ensures fluid-tightness while permitting slight relative movement between the face and the rim.
The curvature of the junction between the nose and the cheek is more accentuated and more variable from one person to another along the horizontal line IIII than at any other point. It is necessary, therefore, to provide greater flexibility and deformability in this plane. To this end, the seam 4 is freed by unsticking or unstitching in the zone in question in such a manner that one of the elements of the bead expands elastically at 3a in bearing against the face.
What we claim is:
A mask for filtering air comprising slightly elastic, microporous plastic sheet material in the form of a pouch open at one side with the lower portion of the pouch being adapted to bear under the wearers chin, While the upper portion of the pouch is adapted to bear against the base of the wearers nose, the edges along said open side of the pouch being bent over inwardly and there secured to the inner surface of the pouch at the top of said upper portion and throughout the entire lower portion to form a thick elastic rim, while the free edges at the sides of said upper portion, being contiguous to bent over and secured edge portions, stand away from said inner surface of the pouch and readily and closely adapt themselves to the shape of the wearers face adjacent the root of the nose.
References Cited in the file of this patent UNITED STATES PATENTS 1,745,657 Beckmann Feb. 4, 1930 2,371,965 Lehmberg Mar. 20, 1945 2,447,450 Williams Aug. 17, 1948