US3276445A - Surgical mask - Google Patents

Description

Oct. 4, 1966 A. J. LANGDON 3,276,445

SURGICAL MASK Filed Feb. 25, 1964 INVENTOR.

ARTHUR J. LANGDON ATTORNEYS United States Patent 3,276,445 SURGICAL MASK Arthur J. Langdon, East Hampton, Conn, assignor to Edward Weck & Company, Inc., Long Island City, N.Y., a corporation of Delaware Filed Feb. 25, 1964, Sell. No. 347,266 1 Claim. ((11. 128146) This invention relates to an improved surgical type mask and more particularly to a breather mask for use by surgeons and assisting personnel during operative and other procedures where it is extremely important that the atmosphere, the surgical equipment as well as the wound be maintained uncontaminated by exhalation of participating personnel.

Numerous variations of surgical masks have been devised in the past to provide a large measure of comfort and bacterial filtration etficiency, but in most designs, including the commonly used gauze type, serious deficiencies still prevail. A common fault is that the wearer must inhale and exhale through the same filtering medium. This can create a possible hazard, as in lengthy operations, where the faculties of the wearer may become seriously impaired by a build-up of exhaled carbon dioxide within the mask. A further objection to prior masks is that they often restrict breathing and thereby induce physical strain and excessive perspiration.

In the development of surgical masks, the problem has been that the elimination of one deficiency most often introduced another. For example, Where the filtration medium is common to inhalation and exhalation paths, the use of high efficiency filter media minimizes bacterial output but contributes to the carbon dioxide build-up. Also as efforts have been made to more thoroughly cover the nose and mouth of the wearer, normal conversation has been impeded. Not the least of the problems has been the sharp increase in costs of more involved surgical masks.

It is therefore a primary object of the present invention to provide a novel surgical mask which overcomes the serious limitations of the prior art designs, while being extremely economical of manufacture. While the mask of this invention may be reused indefinitely, if so desired, the cost is sufiiciently low to make it economically feasible to dispose of it after a single use.

Broadly speaking, the mask of this invention is molded or otherwise formed of a pear-shaped light weight pliable material, such as polypropylene, which is capable of withstanding the high heat of autoclaving without becoming distorted or damaged, thereby assuring durability and reuse. -The mask fits the wearer comfortably, easily conforming to his profile and does not restrict vision. It is formed to encompass the nose and mouth of the wearer and is provided with soft membrane check valve which enables the wearer to inhale with substantially no more effort than required for normal breathing. Exhalation is accomplished with the check valve closed, through an expandable filter element which is retained in the perforated front face of the mask by a snap retained formed integrally with the mask body.

It is thus another object of the invention to provide a surgical mask having an inhalation valve of simple, dependable construction which will open readily on normal inhalation by the wearer and will close positively and immediately as inhalation ceases.

Another object of the invention is to provide a surgical mask having a readily replaceable exhalation filter element of high filtration efiiciency, while minimizing the danger of carbon dioxide build-up.

Another object is to provide a surgical mask in a variety of sizes all of which utilize interchangeable filters of but one convenient size.

3,276,445 Patented Oct. 4, 1966 Other objects and structural details will be apparent from the following description when read in view of the accompanying drawings wherein:

FIG. 1 is a front elevational view of the mask;

FIG. 2 is a side sectional view of the mask taken along line 2-2 of BIG. 1;

FIG. 3 is a transverse sectional view showing the details of the exhalation filter retainer means taken along line 3- 3 of FIG. 2;

FIG. 4 is a sectional view of the inhalation check valve taken on line M of FIG. 2; and

FIG. 5 is an exploded view of the exhalation filter elements ready for assembly.

Referring now to FIGS. 1 and 2, the main body 11 of the mask 10 is formed, preferably of polypropylene, in the general shape of a hollow, truncated cone of generally pear-shaped cross-section, the large open edge of which is rolled outwardly to for ma smooth face-engaging edge portion 12 contoured to snugly engage the nose bridge, cheeks and chin of the wearer. The body portion 11 and edge portion 12 are formed sufiiciently thin to be pliable and thereby conformable to a wide variation of facial features and sizes. A pair of rivets or snap-fasteners 1'8 and 20 are afiixed to the sides of the mask to engage the free ends 14 and 16 of an elastic band 322 for holding the mask securely in position on the face of the wearer.

The front face of the main body 11 has openings 24, 26 and 28 defined by an inwardly rolled pear-shaped edge 30 and a pair of inwardly rolled cross-bars 32 and 34 formed integrally with the body. At the lower surface of the main body 11, there is provided a pair of generally circular inhalation ports 36 and a valve retaining rivet or similar holding device 40. This valve rivet is disposed symmetrically of the two ports 36 and securely and centrally holds valve membrane 50. Body 11 is also provided with a pair of inwardly extending upper button-head projections 58 and 58' (see FIG. 3) and a like pair of lower button-bead projections 60 and 60', the function of which will be hereinafter described.

Referring more specifically to FIG. 4, the inhalation valve membrane 50 and its mode of operation are depicted in detail. The valve membrane is rectangular in form and is made of very thin flexible polypropylene sheet stock adaptedto be normally seated snugly against the lower inner concave surface of main body 11 and to cover completely inhalation ports 36. During times when the wearer is exhaling, the positive pressure in the mask firmly seals the membrane 50 over ports 36 against lea-kage. Due to the extreme light weight and flexibility, the membrane 50 will instantaneously move to the position indicated by the dotted lines when the wearer inhales, opening ports 36. Thus, the membrane 50 functions as a check valve over ports 36 during normal breathing. Actual operation will be discussed in detail below.

Referring to FIGS. 3 and 5, there is shown a pair of planar filter elements 52 and 54, preferably of non-woven cellulose, having a configuration similar to the mask cross-section taken in the plane of the inner margin of rolled edge 30. The exact nature of filter elements 52 and 54 may vary depending upon circumstances, but they are of sutficient thickness and texture to efliciently filter exhalation contaminants. Although two thicknesses are shown, alternatively only one element, or even more than two elements may be used.

The filters are pressed into and held in operative position by a fiat retainer 56 having an outer configuration matching that of the filter elements and of the same mater-ial as body 10. Retainer 56 is formed with a number of openings defined between its outer edge and bridging cross bars 62 and 64 that are complementary to cross bars 32 and 34 respectively, of body portion 11. Thus, the filter retainer 56 firmly holds filters 52 and 54 in position as shown in FIGS. 1, 2, and 3 by snap-in engagement with the two pair of button-head project- ions 58, 58', and 60, 60, previously described as formed in the opposite side surfaces of body portion 11. To assemble the mask, the filter elements 52 and 54 and the retainer 56 are simply snapped into the mask, with the filter elements 52 and 54 between edge 30 and retainer 56.

Button- head projections 58, 58' and 60, 60' are spaced inwardly from the rolled edge 30 just enough to provide a secure, air tight fit. Rolled, integral body " cross-bars 32 and 34 cooperate with retainer cross-bars 62 and 64 respectively to enhance the desired snug fit, yet the flexibility of the several elements permits retainer 56 and filter elements 52 and 54 to be snapped out whenever desired. The filter elements may thus be disposed of readily after use, and new ones reinserted for the next use.

In view of the foregoing discussion, the operation and use of the surgical mask shown in the figures should be readily apparent. The mask is aflixed to the face of the wearer with the upper portion of the pear-shaped body fitting over the nose of the user, while the lowermost portion fits across the chin, directly beneath the mouth. The snug, airtight fit of the mask over the users face is maintained by the elastic band 22 which fits over the head.

Upon inhalation by the user, the check valve membrane 50 will rise (FIG. 4) and uncover the ports 36 to permit as much fresh air as is required to be drawn in. As the user exhales, the positive internal pressure will immediately force membrane 50 to seal ports 36, so that exhalation takes place through the filter elements 52 and 54. The latter elements, of course, trap undesired bacterial contamination, and the like. Due to gravity and also by virtue of the normal tendency of membrane 50 to lie flat, the ports 36 will be closed even during normal momentary pauses in the breathing process. As a result the excape of contaminants is prevented during inhalation, exhalation and breathing pauses.

During exhalation the slight positive pressure imposes an outward force upon filter elements 52 and 54. The secure fit along internal rolled-edge 30 and the crossbars 32 and 34 prevent the filter elements from bowing, whereby the exhalation products must pass through the filter elements 52 and 54 without undesired leakage.

It may be seen that the breather mask of this invention is exceedingly safe and efiective in operation. Carbon dioxide build-up represents no problem whatsoever since the user may inhale as much fresh air as required through ports 36. Normal conversation is not impeded by the mask because of the relatively large filter area, the filters being transparent to sound. The mask may be rapidly assembled immediately prior to auto'claving, and after use the filter elements may be disposed of and new ones inserted with a minimum of effort. Due to the simplified nature of the construction particularly the unitary, thin plastic body 10, the breather mask of this invention is relatively economical in manufacture. This permits the use of the entire mask as a disposable item under many circumstances. Indeed, the breather mask shown may be prepackaged in sterile condition, to be used once and then disposed.

It is a feature of this invention that the design permits the mask to be made in varying face sizes without in any way impairing its utility from the standpoint of convenient filter element replacement. For example, the mask may be manufactured with its base as measured by the outer dimension of pear-shaped rolled edge 12 in two sizes, large and small. The filter area as measured by pear-shaped, rolled edge 30 will be the same for both mask sizes. This permits a hospital to inventory but a single size filter element for replacement in either the large or small mask.

While I have described what is presently considered a preferred embodiment of my invention, it will be obvious to those skilled in the art that there are other changes and modifications which may be made therein without departing from the inventive concept. Therefore, the appended claims are intended to cover all such changes and modifications that fall within the true spirit and scope of my invention.

What is claimed is:

A surgical mask, adapted for the unobstructed inhalation of fresh air from the environment outside of the mask through a pair of ports therein as well as through a filter therein and for the exhalation of air only through such filter to the environment outside of the mask, comprising a thin, relatively flexible, hollow truncated conical body of generally pear-shaped cross-section having an outwardly turned integral smooth edge portion at the larger open end thereof and an inwardly turned integral edge portion at the smaller open end thereof, said body having a pair of spaced ports in the lower portion of the conical surf-ace thereof,

means for removably securing said body on the face of a wearer thereof,

porous filter means disposed across said smaller open end for trapping exhaled contaminants,

thin planar retainer means having a relatively large central opening and a peripheral configuration complementing the peripheral configuration of said filter means and inwardly turned edge portion for resiliently pressing said filter means against the inner edge of said inwardly turned edge portion,

resilient snap retainer means along the inner surface of said body adjacent to said inwardly turned edge portion and cooperating with said planar retainer means for securely and removably holding said'filter means against the inner edge of said inwardly turned edge portion,

a highly flexible, relatively thin, long membrane having a short central region and a pair of relatively long flap ends, each of said flap ends extending outwardly from said central region to removably cover in full a corresponding one of said ports and having an open and unobstructed channel of communication through said corresponding port directly with the environment outside of said mask, and

means for securing said central membrane region to the lower inner surface of said body at a point between said pair of ports to permit withdrawal of said flap ends from said ports during inhalation;

whereby, when the mask is worn, during inhalation said flap ends lift to uncover said ports and permit the unobstructed passage of fresh air into said mask directly from the environment outside of said mask and during exhalation said flap ends securely seal ports against leak-age, the exhalation being vented from said mask to the enviroment outside of said mask through said filter means.

References Cited by the Examiner UNITED STATES PATENTS 1,048,135 12/1912 Cloetta et a1 128l46 2,220,374 11/ 1940 Lewis 128l46 2,798,483 7/1957 Kashima 128-146 3,014,479 12/1961 Matheson 128-146 3,137,296 6/1964 Guutowski 128--146 RICHARD A. GAUDET, Primary Examiner.

W. E. KAMM, Assistant Examiner.

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