Anti-fog surgical face mask with slits

Abstract

A surgical face mask comprising a filtration medium and a sheet of air impervious material, said sheet having slits which define flaps that are outwardly moveable under the influence of exhaled breath to provide paths for directing the flow of exhaled breath away from the eyes of the wearer of the mask.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to surgical face masks and, more particularly, to surgical face masks adapted to prevent moist breath from rising over the upper portion thereof and fogging the eyeglasses of the wearer of the mask.

2. Description of the Prior Art

Surgical face masks have been employed for some time by the operating room staff during surgical procedures. The purpose of the face mask is to prevent bacteria exhaled by the surgeon, or other of the operating room staff, from contaminating the patient undergoing surgery. The face mask comprises a filter medium which is of sufficiently small pore size to prevent bacteria from flowing through the mask.

Older face masks, which were made of folded squares of linen, gauze, or like materials, had relatively low air resistance and were poor bacteria filters. Subsequently, face masks were made which were extremely good bacteria filters but, in general, had higher air resistance than the older masks.

Masks of the latter type sometimes presented problems to the user who wore eyeglasses. As the air resistance of the masks increased, there was a tendency for moist breath exhaled by the wearer to escape at the top of the mask. The exhaled breath, being moist and warmer than the surrounding air, had a tendency to condense on, and fog, eyeglasses worn by surgeons and other operating room personnel.

In our assignee' s copending patent application, Ser. No. 411,873, entitled "Anti-fog Surgical Face Mask" filed on even date herewith, the contents of which application are hereby incorporated herein by reference, there is disclosed a surgical face mask which substantially reduces eyeglass fogging without any substantial decrease in the bacteria filtration efficiency of the mask. This result is accomplished by employing an air impervious element on at least the upper portion of the mask. This air impervious element prevents exhaled breath from moving upwardly from the mask and fogging the wearer's eyeglasses.

While such a mask is quite effective in substantially preventing eyeglass fogging, some wearers have found the mask somewhat less comfortable during use than a like mask without the air impervious element.

SUMMARY OF THE INVENTION

We have now discovered a simple method of making a surgical face mask which alleviates the foregoing problem and, at the same time, retains the "anti-fog" characteristics of the face mask of the above identified copending application. This result is accomplished by providing slits in the air impervious element.

It has been found that the slits in the air impervious element must be so designed and so arranged as to preclude the flow of exhaled breath upwardly from the mask. The slits, whose total number may vary, may have different configurations, and may be arranged in a variety of alignments, so long as they are effective to direct substantially all the exhaled breath passing therethrough away from the eyes of the wearer of the mask.

Thus, according to the present invention, there is provided an improved surgical face mask comprising a body portion having upper and lower parts, said body portion comprising a filtration medium for filtering bacteria, means for securing the mask over the mouth and nose of the wearer, and a sheet of air impervious material across the upper part of said body portion, said sheet of air impervious material having slits defining flaps which are outwardly movable under the influence of exhaled breath to provide paths for directing the flow of said exhaled breath away from eyes of the wearer of the mask.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with reference to the annexed drawings in which:

FIG. 1 is a view of a first embodiment of the mask of this invention shown in position on the face of a wearer.

FIG. 2 is a plan view, with parts cut away, showing the outer surface of the mask of FIG. 1.

FIG. 3 is a plan view, with parts cut away, showing the inner surface of the mask of FIG. 1.

FIG. 4 is a cross sectional view taken along line 4--4 of FIG. 2.

FIG. 5 is a side view, partially in section, showing the mask of FIG. 1 in position on the face of a wearer.

FIG. 6 is a plan view showing slits of a different configuration.

FIG. 7 is a plan view showing slits of still another configuration.

FIG. 8 is a plan view showing a fourth configuration for the slits.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention may be employed in any of the well known surgical face masks such as flat face masks or in preformed contoured face masks. A flat face mask has a body portion which has two major surfaces, i.e., an inner major surface and an outer major surface, and which comprises a suitable filtration medium. The body portion may include, if desired, a facing material disposed on one or both major surfaces of the filtration medium. A flat face mask may be pleated or unpleated, as desired.

The terms "outside" and "outer surface," as used herein, refer to that portion, or surface, respectively, of the mask (or of any element thereof) which is disposed away from the face of the wearer when the mask is in place; the terms "inside" and "inner surface" refer to that portion, or surface, respectively, of the mask (or of any element thereof) which contacts or is disposed toward the face of the wearer when the mask is in place. The term "upper," as used herein, refers to that part of the mask (or of any element thereof) which is nearer the nose and eyes of the wearer when the mask is in place; the term "lower" refers to that part of the mask (or of any element thereof) which is nearer the chin of the wearer when the mask is in place.

Referring now to FIG. 1, there is illustrated, on the face of a wearer, a first embodiment 20 of the face mask of the present invention. Face mask 20 includes a body portion 21 which has a binding 24 along its upper edge and a binding 25 along its lower edge. Body portion 21 also has bindings 23 along the side edges thereof which bindings may be extended at the corners of the mask, if desired to provide tie strings 28 which may be tied at the back of the head of the wearer as shown at 26 of FIG. 1 in order to secure the mask in its desired position. As is well known in the art, side bindings 23 and tie strings 28 may comprise biased fabric tapes and may, if desired, have elastic characteristics. The upper, outer surface of body portion 21 carries a sheet 30 of air impervious material which has generally arcuate slits 30 therein. The upper portion of mask 20 carries a nose clip 27 which may be formed, for example, from a thin strip of aluminum.

The first embodiment of the present invention will now be described in greater detail with reference to FIGS. 2, 3 and 4 of the drawings.

Referring particularly to FIG. 2, main body portion 21 is folded to form pleats 29 which unfold to better conform the mask to the face of the wearer when the mask is put on. In order to prevent exhaled breath of the wearer of the mask from rising and fogging his eyeglasses, mask 20 is provided with a sheet 30 of air impervious material which is disposed across the upper outer surface of the mask. Sheet 30 may be secured to body portion 21 by any suitable securing means as described more fully in the aforementioned copending application.

In the embodiment of FIG. 2, it will be seen that the upper periphery of sheet 30 is secured to upper binding 24. The side peripheries of sheet 30 are disposed between main body portion 21 and side bindings 23 and are held in place by stitching indicated by dotted line 18.

Sheet 30 has slits 31 cut therein which define downwardly projecting flaps 32 best seen in FIG. 5. Slits 31 have a generally arcuate configuration and have an arc distance approximately equal to 1/3 the circumference of a 5/16 inch diameter circle. As shown in FIG. 2, slits 31 are arranged in two rows running from one side of the mask to the other. The slits in each row are arranged in pairs, there being six pairs of slits per row. In the embodiment of FIG. 2, the distance b between one slit of a first pair and the adjacent slit of the next adjacent pair is about three times the distance a between the slits comprising a pair. There are twenty-four arcuate slits 31 cut into sheet 30 which measures about 11/2 inches vertically and about 61/2 inches between the inward edges of side bindings 23.

The inner surface of the first embodiment, seen in FIG. 3, carries bindings 23, 24, 25 which are merely folded-over portions of the corresponding bindings on the outer surface of the mask. The folded bindings are secured to body portion 21 by stitching, indicated by dotted lines 18 in FIGS. 2 and 3. It will be seen that sheet 30 of air impervious material has been folded over the upper edge of mask 20 and continued downwardly along the inner surface of the mask. That part of sheet 30 that lies along the inner surface of the mask has no slits. Sheet 30 is secured only along its upper and side peripheries to the inner and outer surfaces of the mask, thereby providing sheet 30 with a "flap-like" arrangement, best seen in FIG. 4. This flap-like arrangement of sheet 30 is explained in greater detail in the aforementioned copending patent application. It is noted here, however, that the flap-like arrangement of sheet 30 of air impervious material, which allows the greater part thereof to move more or less independently of the outer surface of body portion 21, is to be distinguished from the flaps defined in sheet 30 by the slits 31 cut therein.

Referring now to FIG. 5, there is shown a side view, partially in section, of the mask of FIGS. 1-4 in position on the face of a wearer. Flaps 32, which are defined by slits 31, are illustrated in FIG. 5 in a slightly uplifted position. As indicated by the arrows, these flaps are outwardly movable to provide paths through which exhaled breath may flow. Any exhaled breath flowing in this manner is directed away from the eyeglasses of the wearer, thus substantially overcoming any tendency of the moist breath to rise upwardly and cause eyeglass fogging.

Referring now to FIGS. 6, 7 and 8, there are illustrated various other slit configurations and arrangements which are effective in providing sites for the passage of exhaled breath while at the same time preventing fogging of eyeglasses. In FIG. 6, a series of V-shaped slits has been cut into sheet 34 of air impervious material to form triangular flaps 36 whose apices are pointing toward the lower part of the mask. The sides of the V-shaped slits are about 3/16 of an inch in length and define an angle .alpha. of about 90.degree.. The length of the sides of the V-shaped slits may be varied from about 1/8 of an inch to about 3/8 of an inch, and the angle .alpha. may range from about 75.degree. to about 115.degree.. The slits defining flaps 36 are arranged in the same fashion described earlier for slits 31 in FIG. 2. In FIG. 7, slits have been cut into sheet 44 of air impervious material to form rectangular flaps 46 having vertical sides 46a and a horizontal side 46b. Vertical sides 46a are about 1/8 inch in length and form angles of 90.degree. with horizontal side 46b which is about 1/4 inch long. The length of sides 46a may be varied from about somewhat less than 1/8 inch to about 3/8 inch, while that of side 46b may be varied from about 1/8 inch to about 3/8 inch. As illustrated in FIG. 7, the length of side 46b is preferably longer than the length of a side 46a. The lengths of sides 46a and side 46b may be varied to produce other rectangular flap configurations. For example, the lengths of sides 46a may be made equal to the length of side 46b, thus producing square flaps in sheet 44. Other modifications of the embodiment of FIG. 7 may also be made. For example, the length of side 46b of flap 46 may be increased to provide horizontally elongated flaps; similarly, the length of sides 46a of flap 46 may be increased to provide vertically elongated flaps. Preferably, there are 22-24 flaps in the embodiment shown in FIG. 7, and the flaps are arranged in two rows. The total number of flaps may be varied from about 10 to about 26, the exact number depending, of course, on the configuration and dimensions of the flap. In the embodiment of FIG. 7 it will be seen that the slits in a given row are spaced singly, that is, an equal distance apart, rather than in pairs as described for the previous embodiments.

Referring now to FIG. 8, there is shown another embodiment of the present invention. Slits are cut into sheet 54 of air impervious material to define modified rectangular flaps 56 having sides 56a and horizontal side 56b. Sides 56a are about 1/8 inch long and form an angle .beta. of 125.degree. with horizontal side 56b, which is 1/4 inch in length. The embodiment of FIG. 8 has a total of about 22-24 such flaps which are arranged in two rows and are singly spaced. The angle .beta. formed by the intersection of sides 56a with side 56b may be varied from about 90.degree. to about 135.degree., and is preferably from about 115.degree. to about 135.degree.. Again, the lengths of sides 56a and 56b may be varied from those given above, as may the total number and arrangement of the flaps.

It has been found that flaps 36, 46, and 56, along with the above described modifications thereof, are effective to prevent eyeglass fogging and, at the same time, to provide increased comfort to the wearer of the mask.

The sheet of air impervious material may comprise a soft, pliable film of plastic material such as polyethylene, polypropylene, poly(ethylene-vinyl acetate), polyvinyl chloride and the like. The slits may be formed in the air impervious material in any desired manner; a steel die carrying the desired slit configuration has been found suitable in our work.

The dimensions of the various slits are not critical and may be increased or decreased as suggested herein if desired.

Similarly, the configuration of the flaps defined by the slits is not particularly critical and may also be varied so long as the flaps serve to direct exhaled breath away from the eyes of the wearer. It will be evident that the number of slits, the grouping of the slits, and the number of rows of slits may be varied from those recited above in the description of the preferred embodiments without departing from the spirit or scope of the present invention.

The noun "slit" as used herein, refers generally to an opening made in the sheet of air impervious material with an edged instrument such as a razor blade or a thin edged metal die. By selecting a sufficiently thin edged cutting instrument to make slits in the sheet of plastic film, the width of the openings may be kept extremely small so that substantially no void space is produced by the cutting operation. As the thickness of the cutting edge increases, of course, the width of the opening also increases and a proportionately increasing amount of void space is generated. In the present invention, slits are preferably made in the sheet of air impervious material so that substantially no void space is produced therein. It will be recognized, however, that slits can be made which produce a minor amount of void space in the sheet of air impervious material so long as those slits define flaps which are effective to direct exhaled breath downwardly from the eyes of the mask of the wearer.

Claims

What is claimed is:

1. A surgical face mask comprising a body portion having upper and lower parts, said body portion comprising a filtration medium for filtering bacteria, means for securing the mask over the mouth and nose of the wearer, and a sheet of air impervious material secured to the upper part of said body portion, substantially the entire area of one major surface of said air impervious material overlying said body portion, said sheet of air impervious material having slits defining downwardly extending flaps which are outwardly movable under the influence of exhaled breath to provide paths for directing the flow of said exhaled breath away from the eyes of the wearer.

2. A face mask according to claim 1 wherein said slits define flaps having an arcuate configuration.

3. A face mask according to claim 2 wherein said slits are arranged in rows.

4. A face mask according to claim 3 wherein the slits in each row are arranged in pairs.

5. A face mask according to claim 1 wherein said slits are generally V-shaped, and define triangular flaps whose apices are directed toward the lower part of the mask.

6. A face mask according to claim 1 wherein said slits define rectangular flaps.

7. A face mask according to claim 1 wherein said slits define modified rectangular flaps.

8. A face mask according to claim 1 wherein said slits define flaps having three sides, one of said three sides being substantially horizontally disposed and the other two of said three sides being generally vertically disposed, each of said other two sides forming an angle of from about 90.degree. to about 135.degree. with said horizontally disposed side.