US2881444A - Aerodynamic seal for face masks - Google Patents

Description

April 14, 1959 J. N. FRESH ET AL 2,881,444

AERODYNAMIC. SEAL FOR FACE MASKS Filed May 14, 1956 m S P W R E mH N NSM. R E 0 V D T 1. M R

H ma Unie tate P e 7 2,881,444 AERODYNAMIC SEAL non FACE MASKS John N. Fresh and RichardD. Murphy, Bethesda, Md.

' Application May 14, 1956, sans... ss4,sss

ZClaims. cu-9 (Granted under Title as, Us. cost 1952 see. 266) The invention described herein may be manufactured andused by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

' This invention relates 'to face masks or shields and more particularly to a face seal for open-ended wind masks which permits such masks to be worn for extended periods of time without imposing discomfort due to headband pressures necessary to" keep them substantially airtight about the wearers face.

Prior art open'ended air-stagnating-wind masks encii'cling portions of a wearer's face 'a're'adapted to protect a wearers face, and particularly his, eyes against the hazards of high winds and/or extremecold. Sealing about the face is-required-toprevent'l'achrymation and is usually effected through a resilient'b'ead or the like about the facecontacting-periphery" of the mask. A strap is*usually-employed-to maintain the bead pressed against the face.

Because such masks are worn over protracted periods of time comfort is a prime consideration. In the prior art, severe headband pressures were required to effect proper sealing against wind pressures buffeting the mask from different angles. These pressures produced discomfort about the face and headaches after prolonged wear. Further, since masks are not usually manufactured for particular individuals, and due to different facial contours, sealing, in many instances, could only be effected by employing headband pressures which deformed the masks. Such an expedient reduced the effect of the seal and multiplied the deleterious effects on the wearer. Such an expedient also reduced the time the mask could be worn and affected the alertness of the wearer during the time it could be worn.

The instant invention provides a face seal for a face mask which gives greater comfort over longer periods of time by reducing headband pressures necessary to provide efficient sealing. The seal comprises generally a thin circumferential flap and a plurality of spaced annular elements all integral with the mask frame, and wherein said elements form a plurality of air passages which act individually to seal the mask by taking advantage of the stagnation pressures in the mask, and together to provide a comfortable resilient cushion through distribution of pressures over a greater area of the face. The frame of the seal further incorporates a bellows which in combination with said cushion enables the mask to adapt to a variety of facial contours, eliminating the need for severe headband pressures which would tend to deform the frame about the face contacting periphery, without impairing sealing action.

An object of the invention is to provide a face mask employing an aerodynamic seal which enables it to be worn comfortably for extended periods of time.

Another object of the invention is the provision of a seal for a wind mask which conforms to a variety of facial contours while eliminating the requirement of severe headband pressures to effect sealing.

A further object of the invention is the provision of a face seal for a wind mask which utilizes the difference in pressures between ambient and the pressures within the mask to render the mask substantially airtight.

Another object of the invention is the provision of a seal for a wind mask which acts positively to render the seal more airtight upon the occurrence of leaks therearound.

Still another object is to providea cushion and seal which renders the abrasion against a wearers face negligible.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detail description when considered in connection with the accompanying drawings wherein:

Fig. 1 is a perspective view of a goggle-type wind mask in accordance with the invention;

Fig. 2 is a plan view in elevation of the wind mask of Fig. 1; and

Fig. 3 is a longitudinal cross sectional viewof the wind of a goggle type contoured in accordance with an average.

facial structure. The mask :5 is secured to a wearers face 6 as by a strap 7 or the like adapted to hold a seal and cushion generally designated by reference 8 (Fig. 3) against said wearers face. It is to be understood that the instant invention may be utilized with'face shields which protect the whole of a wearers face or with breather type masks which cover only the nose and mouth portions of the wearers face.

Specifically the wind mask comprises an annular substantially elliptical relatively resilient tubular frame body member 9 of rubber or plastic composition. Secured to the frame body member 9 by any suitable method is a tubular open-ended transparent wind shield 10 made of plastic or the like, having good temperature stability over wide ranges. The strap 7 of resilient material or nonresilient material with means for positively adjusting it in length is provided and secured as at 11 to the frame member 9 by any appropriate means.

Considering the mask by itself, the face contacting edge (Fig. 3) of the frame member 9 incorporates the seal and cushion 8 which comprises a fringe with a plurality of oval elements 12. The outermost element is an oval flap 13 substantially parallel to the longitudinal axis of the frame body member 9 adapted to flare outwardly against the wearers face during use. The remaining elements are oval ridge-like projections or fingers 14 integral with or originating from a thickened portion of the frame body material 9. Each of the fingers or elements 13 and 14 is much thinner than the main portion of the frame member 9 from which it extends. These fingers 14 project inwardly at an acute angle and increase in length toward the axis of the mask. Oval spaces 15 between the projections 14 are such as to form a plurality of air passages which together with the projections 14 act collectively to form a flexible cushion against the wearers face and individually to provide a. plurality of seals about the wearers face as will he described later. Intermediate of the frame body 9 between the cushion and seal 8 and the transparent shield 10 are provided two wedge-shaped depressions 16 on the opposite short sides of the elliptical frame member 9 Patented Apr-f 14, 1959* The principle of operation of the seal and cushion described is to divide the total pressure differential between the inside -andvoutside of. themask into, a series. of smaller differential pressuresacross each of. the elements. IZ Inasmuch as; the reaction of a given pressure differential. .by a single element determines. the normal ,force hetween. .that,element orlsealand the face, assuming the seal perfectly fits theface, dividing that same pressure differential by employinga plurality. ofelements 12 distributes the normal.force or pressure against the face and thereby reducesthat pressure underthe same atmospheric conditions to give a cushioning effect. v

wI use the-outermost element orlfl ap 13.:splays outwardly ,of thewearersface and the othenelements-or projections 14 deflect inwardly of the wearers face. The spaces. 15 between;projections14. entrap airwwhen in usevandnvarious pressure .levels,across.themulti-element 2:1;

seal aremaintained b'y slight leakagefrom each element 12. to anadjacent one inthe directionof, decreasing staticpressure. This slight leakage. is not objectionable so long as, the velocities adjacent the Wearers eyes do not produce lachrymation. Should leakage past one. of the ele-. mental} become-appreciable the local static pressureat the leak will be reduced in accordance with the aerodynamic principle of pressure reduction with .increased velocity of flow. This reduction of pressure at the leak due to flow in an adjacent air passage 15 willcause the next adjacent projectionor. finger 14 to .be drawn toward the wearers face resulting in an automatic sealing action.

1 The pliable fringe and bellows 16 in combination allow the automatic adaptation of the mask to. a variety of. facial structureswithout the necessity for the utilization of headband pressures which-would tend to deform the mask and impair the seal, Any depression infacial contours will be sealed by individualprojections14 notbeing depressed tothe same degree as they would be over a' convex portion of the wearer's face. The" action of thewbellowsu lfi isradapted torallow thernask to adjust to faces of varying width with limited deformation of the seal portion of the frame body.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claim's the invention may be practiced otherwisethan as specifically. described What is claimed is #15. A mask of a type .describedkomprisin'g a -"frame member of voval shap e, said frame-,membenhaving a bellow-like constinct'io'n' 'at' its sides centrallythereof, a

1,. flexible seal at the face end'of said ;frame member adapted towardthe, otherendof said mask.

to ea the ma ktq a. we r rs fa e an str rz mea s for securing the -mask "to" the head-ofthe Wearerfsa'idstrap means being secured to said frame member between said bellow-like construction and said seal.

2., Ai-mask asdefined .in, claim .1, but further-characterizedbysaid sealcomprisinga plurality of 'flexiblefingers and a flexible :flap, Saidfingersbeing adapted. to: splay inwardly on the wearersface, and being. slightly graduated transversely, being. relatively. longer in a direction I v ReferencesCited in the patent I UNITED STATESlATENTS FOREIGN PATENTS France.... Sept. 29, 1954

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