US 2652828 A
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Description (OCR text may contain errors)
p 1953 J. N. MATHESON 2,652,828
RESPIRATOR Filed March 26. 1951 4 Sheets-Sheet 1 Zmnentor James MMathefion attorney;
Sept. 22, 1953 J. N. MATHESON RESPIRATOR 4 Sheets-Sheet 2 Filed March 26. 1951 I 3nnentor James MMa theaqn attorney Sept. 22, 1953 J. N. MATHESON 7 2,652,828
RESPIRATOR Filed March 26, 1951 4 Sheets-Sheet 3 I I 380 i z 14 15 1 u I 3nventor I/amas NMaiheson (Ittorneg Sept 22, 1953 J. N. MATHESON RESPIRATOR 4 Sheets-Sheet 4 Filed March 26. 1951 3nventor James AKA [11111165012 (Ittomeg v Patented Sept. 22, 1953 UNITED STATES PATENT OFFICE RESPIRATOR Application March 26, 1951, Serial No. 217,540
The present invention relates to improvements in a respirator of the type which is held in sealing engagement with the face of the wearer along a contour which surrounds the nose, mouth and chin and adapted to give protection against dusts, mists, fumes, gases and vapors of various kinds. An outstanding disadvantage of common designs of the above type of respirator is that they are not comfortable to wear. Therefore, even after they are worn a relatively short time, substantial discomfort results which oftentimes impels the wearer to remove the respirator and thereby expose himself to the deleterious effects of breathing dust and noxious fumes.
A further disadvantage of commonly used types of respirators is that they are somewhat complicated in construction, requiring special stiffening material, such as metal wire, bands or straps-- furthermore, they conform to the features of the face only when worn low on the nose, and are adaptable to fit a limited number of nose bridge or facial contours, thus requiring the stocking of a number of different sized respirators. Still another outstanding disadvantage of commonly used types of respirators is that the inhalation disc-type valve which is generally fastened at the center is activated into vibration around its peripheral edge by the voice of the wearer to such an extent as to distort and mute the voice into an incoherent jumble of words. Furthermore, replaceable filter units which are detachably secured to the face piece generally have threaded connectors which often involve diiiiculty in engagement before rotating and require a considerable number of rotations before a dust-tight connection is secured. Therefore, it is often necessary to remove the respirator in order to replace filter units.
An object of the present invention is to provide a novel respirator which is devoid of the above named disadvantages of common types of respirators.
A further object of the invention is to provide a respirator having a face piece which is extremely comfortable yet snug fitting, self-adjusting, and providing floating, cushioned engagement with the face to provide a gas-tight seal therewith.also which is adapted to fit a large variety of facial contours, especially over the critical nose region.
A further object of the invention is to provide a self-aligning headband for a respirator which will create a tight fit with pressure adjustability .around the entire peripheral contact edge so that the wearer can place straps to suit above the ears and across the top of the head, thereby concentrating most of pressure underneath, the large chin area and reducing the pressure over the 7 Claims. (Cl. 128-146) nasal region, or, below the ears, thus providing an extremely comfortable yet very eflicient respirator capable of being worn for extended periods of time with 'a minimum of discomfort.
. A still further object of the invention is to provide a respirator having improved dual, negative acting, air inlet valves having lower inhalation resistance and which eliminate distortion and vide, in a respirator, an improved connector which enables relatively easier and quicker attachment'or removal of a replaceable filter unit or cartridge, even while the respirator is being worn.
Other objects and advantages of the present invention will become apparent from a study of the following description, taken with the accompanying drawings wherein:
Fig. 1 isa front elevational view of a respirator embodying the principles of the present invention, and showing one of the filter cartridges removed from its support on the respirator;
Fig. 2 is a front elevational view of the face piece shown in Fig. 1 and more clearly illustrating the substantially triangular or pear shape and other features thereof;
Fig. 3 is a vertical sectional view taken along line III-III of Fig. 2 and which more clearly shows the inner roll contour line and specifically, the variations in wall thickness in and around the parting line as well as along the frontal section and plateau; 1
Fig. 4 is a horizontal sectional view taken along line 'IV -IV'of Fig, 2 and showing the general shape of the lower half of the face piece;
Fig. 5 is an enlarged sectional view taken along line V.V of Fig. l, and showing the design of the quick-clip incline plane seal and the inhalation port and valve;
Fig. 6 is a vertical sectional view of a filter unit having a flat disc type of filter;
Fig. '7 is a vertical sectional view of a filter unit having an accordion pleated filter;
Fig. 8 is a rear elevational View of the respirator illustrated in Fig. 1 showing the inner roll peripheral contour, and the position and shape of the improved inhalation valves, and
Figs. 9a and 9b are plan views of two component headband parts which form the pressure Ja 1ijustable self-aligning headband shown in Referring more particularly to Fig. l of the drawings which shows a respirator involving the principles of the present invention, numeral I denotes a face piece which is preferably molded 1 rubber or similar flexible material and which is somewhat triangular or pear-shaped. Face piece i is designed to cover the nose, mouth and chin of the wearer and adapted for air excluding contact between the face-contacting periphery thereof and the face of the wearer. Face piece has a top convex portion 2 and two side concave portions 3 along its contour which are adapted to surround the nose. Attached to each of the lower lobes of face piece I is a readily detachable and replaceable filter or cartridgeunit denoted generally by the numeral 4. The lowermost portion of the face piece surrounds the chin and adjacent thereto is an exhalation valve 5. The respirator is held against the face of the wearer by means of headband 43'M--whichis attachably secured to the filter unit supports.
An important feature of the invention resides in the specific shaping of the face piecexl', particularly along the face-contacting portion thereof, which is best illustrated in Figs. 2, 3 and 4, which shaping provides amazing improvement in comfort and enables the wearing of a respirator for a long period of time before any discomfort is apparent, considerably longer than possible with common types of respirators. As shown more clearly in Figs. 2, 3 and 4, face piece 5 has an inwardly curved, face-contacting edge portion 6 which, at the nasal section, extends of the order of inch outwardly from a parting line i denoted by dash lines and gradually increases to a distance of the order inch from the parting line along the cheek-contacting edge portions for providing air excluding contact with the varying facial contours. Edge portion 8 extends substantially along a flat plane principally at the nose-contacting portion. It has been found by experiment that by forming the facecontacting edge portion 6 along a flat plane instead of having it extending inwardly at the nose portion as is commonly done, the face piece is more adaptable to fit varying'nasal and facial contours and may be worn either high'or low on the nose with equally 'efi'icient face-contacting, air-excluding engagement, and without discomfort. The inwardly turned face-contacting edge portion (5 is greatly reduced in thickness beginning from the parting line and extending along its entire curvature, being approximately 0.025 inch in thickness around the nasal region and increasing abruptly in thickness at the parting line I. From parting line 1 the thickness is doubled side wall portions -8 and finally increases to about 0.125 inch along the remainder of the side wall portions and the front plateau 9. Thus the portions 8 and 9 will give sufficient rigidity to the face piece so that it will retain a given shape without stiffening elements. The abruptly thinner inturned marginal portion 6, because of its thinness, willv be extremely yieldable and collapsible so as to form a cushion-like, air excluding contact with the face which. will enable it to mold itself to varying facial features encountered with the exertion of very slight compression in order to give an air-tight seal and to eliminate noticeable pressure points, particularly over the critical nasal region. At this region, the extreme thinness of inturned edge portion a together with the disposition of the marginal portion substantially along a flat plane allows the respirator to be worn either high or low on the nose without the loss of the air-tight seal. Also, greatly increased comfort without the sacrifice of efficiency is provided as well as increase in the adaptable fitting range to a greater variety of facial contours.
At the base of face piece I there is provided an exhalation valve 5 including an outlet aperture II which is closed by a positive acting, air outlet valve l2 which consists of a thin rubber disc secured centrally thereof to a substantially wheel-shaped portion Ia of the face piece, including a plurality of apertures extending between radially extending spoke portions radiating from. the hub-like portion and terminating in a rimportion having a circumferential groove for providing a detachable, air-tight fit therewith (seeFig. 3).
Extending through each of the cheek surrounding portions of the face piece is an aim-inlet aperture [3 surroundedby a grommet I l.
As will appear more clearly in Fig. 1, grommets i4 serve as means for securing the base portions of a pair of shallow cup-shaped filter supports or holders 1% made of plastic or light metal, such as aluminum, or any other suitable material. A plurality of radially inwardly extending flanges 16 are integrally formed on the mouth portion of the cup-shaped support It. Contained within the cup-shaped support is an annular rubber gasket 20. Thus the filter support assembly described enables quick attachment or detachment of a replaceable filter cartridge unit, such as ll, or a repleaceable filter unit of the type shown either in Fig. 6, employing a filter disc, or in Fig. '7, employing an accordion-shaped hollow filter pad.
As will appear more clearly in Fig. 1, the filter cartridge I! which is shown removed from its holder comprises a hollow cylindrical plastic or metal case it having three (or more) integrally formed, radially outwardly extending flanges 19 which are adapted to cooperate with the radially inwardly extending flanges it of the filter holder l5. Each flange 9 has one end 5911 which-is very thin or. substantially pointed and which gradually increases in thickness, forming an inclined plane until reachin a point. l9b after which'it levels off and retains the same thickness orheight until it reaches an abruptly upwardly extending raised or stop portion E at the other end thereof. Thus the three integral flanges [9 of the cartridge may be quickly inserted between flanges I6 of the holder l5 and the cartridge is then turned clockwise so that the inclined portions of the flanges slide underneath flanges it to provide a wedging action, thereby progressively clamping flanges it against the rubber gasket 20 seated in the filter holder until the stop portions [90 of the flanges come into contact with flanges It, or until the rotation has been forcibly terminated. The compression between the flat or bottom surfaces of the flanges i9, which are flush with the inner edge of case it, and gasket is suificient to provide an air-excluding contact to prevent contaminated influent air from being drawn through the sealed joint. It will be seen that this improved, quick-clip, inclined plane connection requires only turn of the filter cartridge to provide an air-tight seal as compared to threaded connectors commonly used on most respirators which usually require at least 2 revolutions to tighten the seal. Also, the operation of attaching or removing the filter cartridge is simple and may be done while the respirator is being worn and without the difficulty of initial threading of the connector as is sometimes encountered in screw threaded connectors.
The details of the replaceable filter cartridge I l are more clearly shown in Fig. wherein it will be seen that the hollow cylindrical case I8 en'- closes a chemical charge 24 which is retained by disc-shaped filter pads 25 and 26 of felt or similar material and against which there are laid screens 21 and 23 of small mesh. The outer edge of the case I 8 is rolled inwardly to compressthe screens and seal the chemical charge against the integral circular ledge 29 of the case 88 which extends radially inwardly along substantially the same plane in which radially outwardly extending flanges I9 are located.
Instead of using a replaceable filter cartridge I! as shown in Fig. 1, it will be noted that the filter supports or holders I5 are adaptable to engage and support other types of filter units with equal facility, such as the filter disc unit shown in Fig. 6 or the accordion or pleated hollow filter unit shown in Fig. 7, since both of these units are provided with radially outwardly extending flanges, similar to I9 of cartridge unit I'I, therefore will be attachable in the same manner.
Referring more particularly to Fig. 6, it will be noted that the bottom of cup-shaped support I5 is provided with a circular ledge Isa at the periphery thereof. A cup-shaped metal or plastic shell or cover BI is employed as a filter sealing retainer. Cover 3! is relatively shallow in depth and is perforated on its face portion by a plurality of holes. It is provided with an inwardly extending circular edge portion 32 as well as three outwardly extending flange portions 33 which are similar to flange portions I9 of the cartridge I'I. As the cover 3| is placed on filter holder l5 and turned clockwise about turn, the inclined portions of flanges 33 will slide underneath flanges IE of the holder and cause progressively tighter engagement and sandwich a dish-shaped filter pad 34 between the cover 3| and the holder I5.
Fig. '7 shows a structure very similar to that of Fig. 6, but wherein a hollow pleated or accordion type of filter pad 55 is provided and wherein the ring-shaped filter pad portion 35a is clamped between a perforated cover 36 and filter cup I5 by means of flanges 31 integrally formed on the marginal edge portion of the cover 35 which are similar in construction to flanges I9 in Fig. l and are adapted to be guided'by the inwardly extending flanges I6 of holder I5.
Thus various types of filter units may be used interchangeably on the respirator.
Another important feature of the invention resides in the design of the inhalation valve with the object of reducing inhalation resistance as well as to eliminate or minimize voice distortion. As will appear more clearly from Figs. 5 and 8, the metal grommets I 4 which secure the filter .holder I 5 to the face piece I provide inhalation.
ports or holes therethrough. On the inner side of the face piece and covering these holes there are provided a pair of substantially elliptical, thin sheet rubber, negative acting valves 38 whose central portions serve to flex inwardly toward the face of the wearer upon inhalation, permitting incoming filtered air to enter the face piece through the inhalation ports, and which will flex outwardly when exhaling, thereby closing the inhalation ports by seating on the grommets I4. This will prevent exhaled air from entering the filter unit which would otherwise impair the eificiency of the filter. Each of the valves 38 has two holes 38a located on diametrically opposite portions of the major axis thereof and located about inch inwardly from each edge for securing the valves to lugs 39 which are struck out from and integral with face piece I. Alternatively a separate substantially annular plate .(not shown) carrying lugs 39 may be clamped inside of face piece I and held in place by the inturned edge of grommet I l. Thus valves 38 are retained in a loose fitting position while covering the inner rim of grommets I4. With such design, inhalation resistance is considerably reducedfurthermore, there is eliminated the resonating vibration so often created with a cylindrical, centersecured type of valve as commonly used by virtue of the vibration around its peripheral edge initiated by the voice of the wearer which causes distortion and muting of the voice into an incoherent jumble of words.
At the lower part of the face piece facing downwardly and away from the plane ofthe marginal edge portion 6, there is provided an exhalation port or outlet aperture on which is mounted an'exhalation or outlet valve IZ' sub stantially disc-like and umbrella shaped and having a stud M forsecuring it centrally to the hub portion of the valve seat so that when air is exhaled the disc diaphragm valve 52 will flex outwardly at its periphery, thereby uncovering the opening I I and allowing expired air to escape. In the pause between inhalation and exhalation, valve I2 will return to its normal position. On inhalation, valve I2 will be drawn tightly over the valve seat opening so as to form an air excluding contact between the valve and seat and prevent contaminated air from leaking into the face piece I.
Figs. 9a and 9b show an improved self-aligning, head strap assembly, comprising two halves, 43 and 44. Half portion 43 has a pivoting elastic strap 45 crossing through a buckle slide 46 and having snap'buttons ll at its ends which are adapted to be snapped to either pair of snap studs 48 or 49 located on the back of filter holders I5 as shown more clearly in Fig. 8. A single elastic strap connector 50 has one end secured to the other side of the buckle slide 46 and its other end fastened to a set hook 5I which is adapted to engage an adjustable slide and eye 52. Slide 52 may be slid and adjusted along one end of a single elastic strap 53 whose other end is secured to buckle slide 54. Another pivoting elastic strap 56 is slid through the other side of buckle slide 54 and provided at the ends thereof with snap buttons 5'! which are adapted to snap onto the remaining pair of snap studs 48 or 69 shown in Fig. 8. Thus, when the headband is adjusted so as to tightly hold the face piece against the face, there will be provided a gas-tight seal with additional comfort and adjustability available around the entire peripheral contacting portion of the headband and automatic adjustment by the pivoting elastic straps 45 and 56. Thus, the wearer can place the straps to suit above the ears, across the top of the head and thereby concentrate most of the pressure underneath the large chin area and reduce the pressure over the nose bridge or below the ears.
Thus it will be seen that in accordance with the present invention there is provided a highly eflicient respirator in which the face piece is so shaped and designed as to provide a cushionlike, readily collapsible contact with the face of the wearer, insuring a gas-tight fit over varying facial contours with amazing comfort; furthermore, there are provided inhalationvalves which a're of a construction so as't'o' considerably reduce inhalation resistanceand minimize headband for distributin pressure and avoiding concentration of the pressure along the nasal region of the face piece; all of which features considerably improve the efficiency of the respirator and its comfort in wear.
While I have illustrated and described several specific embodiments of my invention, it will be understood that these are by way of illustration only, and that various'changes and modifications may be made within the contemplation. of my invention and within the scope of the following claims.
1. A respirator comprising'a face piece of resilient material and of substantially cup-shape, said face piece having a substantially pearshaped contour along its mouth portion and having an integral outwardly and inwardly turned marginal edge portion of substantially semicircular cross-section extending from a parting line on said mouth portion, said marginal edge portion being substantially thinner throughout its entire cross-section than the adjoining portion of the face piece and abruptly reducing in thickness at said parting line which is substantially along a flat plane at the mouth portion of the face piece to provide a highly cushioned, gas-tight fit either when the face piece is vorn high or low on the nose of the wearer and to avoid the necessity of a cross-piece for tying opposite sides of said face piece.
2. A respirator including'a face piece of molded elastic material and being of substantially cupshape with a pear-shaped contour at its mouth portion and having an outwardly and inwardly turned marginal edge portion of substantially semicircular cross-section extending from a parting line disposed along a flat plane on said mouth portion and which is adapted to fit against the face of the wearer in gas excluding contact relationship, the thickness throughout the crosssection of said marginal edge portion being about one-half of that of the immediately adjoining mouth portion of the face piece and abruptly changing at said parting line so as to provide readily collapsible cushion-like engagement with the face of the wearer, the upper portion of said marginal edge portion being adapted to fit about the nose of the wearer and being disposed along a flat plane to permit wearing either high or low on the nose of the wearer and to avoid the necessity of a cross-piece for tying opposite sides of said face piece.
3. A respirator as recited in claim 2 wherein said marginal edge. portion extends outwardly from said mouth of the face piece of the order of w s inch and has a thickness of the order of .025 inch around the nasal engaging portion, which thickness changes abruptly at the mouth portion, increasing to about double the thickness along the side wall of the face piece and progressively increasing to a greater thickness along the front portion of the face piece.
4. A respirator comprising a face piece of substantially cup-shape and having a pear-shaped contour along its mouth portion and including filter holders of shallow cup-shape secured'by grommets to the lower lobesrof theface piece defining air inlet ports, said holdersprovided at their: mouth with spaced, radially inwardly extending flanges and having annular gaskets supported therein along the periphery thereof, said respirator also including filter units having spaced, radially outwardly extending flanges extending from their base portions, said flanges having inclined edges adapted to cooperate with said radially inwardly extending flanges for providing gas-tight, engagement between the bases of said filter units and said gaskets.
5. Apparatus recited in claim 4 wherein said filter holders are provided with, peripheral seat forming ledges at their marginal portions for supporting said gaskets and wherein each of said radially inwardly extending flanges of said filter units comprises an inclined plane portion, an adjoining, intermediate portion ofv constant thickness and terminating at the other end in an upwardly projecting stop portion which .is
adapted to be arrested by said inwardly extending flanges of said filter holders as the filter units are rotated for effecting a gas-tight seal between the units and holders.
6. A respirator comprising a face piece having an air inlet aperture defined by a grommet, a thin flexible, substantially elliptical-shaped inlet valve secured solely at two points near the opposite edge portions of its major axis to the inside of said face piece and adapted to lie flat against the inner portion of said grommet to form an air excluding seal therewith and minimize voice distortion as well as breathing resistance.
7. A respirator comprising a face piece having an air inlet aperture, a shallow cup-shaped'filter holder having a hole at the bottom thereof which is in registry with said inlet aperture and held thereagainst by a grommet, said filter holder having an annular marginal seat forming a gasketsupporting ledge, an annular gasket supported on said ledge, a plurality of circumferentially spaced, integral, radially inwardly extending flanges projecting from the mouth portion of said holder, and a filter unit comprising a substantially cylindrical cover portion having a plurality of circumferentially spaced, radially outwardly extending flanges projecting from the base portion thereof, each .of said flanges having an end portion in the form of an inclined plane, an intermediate portion of constant thickness and the other end portion having formed thereon an upstanding stop for engagement against said inwardly extending flanges when said filter unit is rotated with. its flanges inwardly of said filter holder.
JAMES N. MATHESON.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,213,760 Dimick Jan. 23, 1917 2,019,928 Punton Nov. 5, 1935 2,362,382 Lehmberg Nov. '7, 1944 2,371,965 Lehmberg Mar. 20, 1945 2,462,005 Schauweker Feb. 15, 1949 2,505,173 Conley Apr. 25, 1950 2,578,621 Yant Dec. 11, 1951 FOREIGN PATENTS Number Country Date 831,819 France June 13, 1938 853,770 France Dec. 16, 1939