US 2893387 A
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Description (OCR text may contain errors)
y 7, 1959 V. F. GONGOLL. ETAL 2,393,158?
RESPIRATOR Filed April 25, 1953 INV ENT OR. gar/206,1 Gango/l and u //1 er 1; .9 5
Xrromvsv United States Patent Ofiice 2,893,387 Patented July 7, 1959 RESPIRATOR Application April 23, 1958, Serial No. 730,432
3 Claims. (Cl. 128-146) This invention relates to respirator, and, more particularly, to an industrial respirator including a face piece and removable filter for filtering dust and obnoxious fumes. This invention relates to an improvement of James N. Matheson application Ser. No. 557,466, filed January 5, 1956 by the present assignee.
Common types of industrial respirators including a removable filter have generaly been made in two parts, namely a face piece and a filter box or holder, detachably secured to the face piece in an air tight manner. This type of respirator has an outstanding disadvantage in that it is extremely difiicult to maintain a perfectly air tight fit between the filter holder or box and the face piece, particularly after these parts have been detached and put together again a number of times. Another disadvantage is that in cleaning the respirator, it is difiicult to clean all the parts without taking them apart and putting them back together again which consumes considerable time.
A further disadvantage of commonly used dust filtering respirators with removable filters and of the above described type is that in cases wherein the face piece is made of metal or other rigid material, a rubber liner is required on the periphery to form an air tight fit with the face. However, such liner does not provide a comfortable fit with the face because of the metal backing of the rigid face piece, moreover, difficulty has been experienced in keeping the rubber liner in place in an air tight manner. Additional difiiculty is experienced when the respirator is to be washed, necessitating the removal of the rubber liner.
Another disadvantage of commonly used respirators including a filter box with a removable filter pad, generally supported by a rigid, open plastic frame, is that considerable difiiculty has been experienced in making a construction that is relatively fool proof in maintaining a dust tight connection with the filter. Commonly used types of respirators have a rigid filter holding box, and very commonlywhen the user replaces a filter he does not arrange the filter pad properly, or perhaps does not insert the filter pad and frame holder into the box sufficiently to insure an air tight connection between the filter holder box and the margins of the pad so as to prevent leakage into the respirator of dust laden air. Nor are suitable means available for simply and securely holding or locking the filter pad and frame in place or for aligning the parts.
An object of my invention is to provide a respirator of the industrial type which is devoid of the above named disadvantages and which is integrally molded in one piece, instead of two detachably connected pieces, therefore which completely eliminates leaks between the face piece and filter box.
Another object of my invention is to provide a novel respirator including an integral rubber face piece and filter holding box of such construction as to insure a dust-tight fit with a removable filter pad and filter supporting frame and which will insure that the filter pad and frame will be securely held and locked within the holder at all times without the danger of dislodgment or loosening or the development of leaks.
A still further object of my invention is to provide an efficient respirator of relatively simple, inexpensive, one piece construction so that the entire respirator may be cleaned as a single unit. without the necessity of disassembling the parts, and which will provide a truly airtight fit about the nose, cheeks and chin of the wearer which greatly surpasses the fit usually obtained by previous type respirators.
Other objects and advantages of the present invention will become apparent from a study of the following description taken with the accompanying drawing wherein:
Fig. l is a perspective view showing a respirator embodying the principles of the present invention and showing the filter retaining frame and filter slightly withdrawn from the facepiece to more clearly illustrate the construction thereof;
Fig. 2 is a vertical cross sectional view taken along line 2-2 of Fig. 3;
Fig. 3 is a rear view of the respirator shown in Figs. 1 and 2 with the exhalation diaphragms removed to more clearly show the exhalation ports;
Fig. 4 is an enlarged, cross-sectional view more clearly illustrating the exhalation valve shown in Fig. 2; and
Fig. 5 is a front elevational view of the filter-retaining frame shown in Figs. 1 and 2.
Referring more particularly to the drawing, numeral 1 denotes a facepiece of rubber or similar flexible material, which facepiece is of substantially pear-shaped outline and somewhat cup-shaped in form, and has a mouth or marginal portion which is adapted to surround the nose, cheeks and chin of the wearer in an air-tight manner. The facepiece is held against the face of the wearer by a strap 12 (partially shown), the ends of which are detachably secured to the sides of the facepiece by snap fasteners 12a. The facepiece preferably includes an ac cordion-shaped or pleated portion 2 which enables the nose surrounding portion to more easily flex forwardly to conform to different nasal shapes of the wearer and to permit wearing of the facepiece in higher or lower locations on the nose as desired.
The facepiece 1 has an integral front wall portion 3 of substantially triangular outline and an integral rear wall 4 of similar outline. On rear wall 4 there are provided a plurality of apertures 4a forming the inhalation valve, which apertures are surrounded by a valve seat portion of rear Wall 4 for seating an inhalation valve diaphragm 4b of somewhat trapezoidal shape, as shown in Fig. 3. Integrally molded with the rear wall 4 is a cross-shaped portion 4c defined by said apertures 4a and which serves as a support for an integral rubber or hard plastic rivet 4d which serves to detachably support the inhalation diaphragm by passing through a hole at substantially the center thereof. Thus, as the wearer inhales, air is drawn through the apertures 4a so as to flex the diaphragm 4 in the direction toward the wearers nose.
The respirator 1 has an integral bottom wall portion 5, also of rubber or other flexible material, which is provided with two pairs of exhalation ports 5a, as more clearly shown in Figs. 2 and 3. Each of the exhalation ports 5a is provided with an' exhalation valve in the form of a rubberor flexible diaphragm 6 which is adapted to be seated against concave shaped portions on the outer surface of the bottom wall 5 and positioned so as to close ports 5a. The diaphragms 6 are not shown in Fig. 3 to more clearly illustrate the ports, but are shown in Figs. 2 and 4. V
An important feature of the invention resides in the specific mounting of exhalation valve diaphragm 6 by means of a pin 7, preferably made of nylon or other hard plastic material. Pin 7 is similar to a collar button and is provided with a small head 7a and an enlarged head 7b mounting the diaphragm onto the outer surface of the exhalation valve. It should be particularly noted in Fig. 4 that the. lowermost or enlarged head 7b is provided with a conical portion 70 adjacent the shank which isdisposed at an acute angle relative to the bottom surface of thewall 5,.instead of being flush therewith. By providing such conical portion there will be less resistance to exhalation .or flexing of the diaphragm 6 since the shank of pin 7 will serve as a pivot point instead of the vouter perimeter of the head 7b, which is of substantially greater radius. Thus the diaphragm can be moved farther away .from the valve seat. The conical surfacel7c acts as a stop for limiting outer flexing movement of diaphragm 6 as the result of exhalation.
Another important feature of the invention resides in the provision of means for securely locking the filter retaining'frarne in place. More specifically, the filter retaining frame 9, which may be of suitable-hard plastic material, such as nylon, is provided with lowermost air inlet holes 9a through which air may be inhaled into the filter chamber or box. Air then passes through filter 10, which is of substantially butterfly shape and folded centrally over the filter retaining frame 9, as shown in Fig. l.
Considerable difficulty has been experienced in the past in maintaining an air-tight seal between the filter and the filter box portion ofthe respirator housing. After considerable experimentation, we have finally solved this problem by providing a hole 30 on the lowermost portion of each sidewall la-of the respirator and by providing integral pins 90 which extend from the two lowermost corners of the filter retaining frame 9. Thus, after the filter 10 has been draped over the frame 9 and pushed into the filter box portion of the respirator housing at the front part of respirator 1, by first spreading the flexible sidewalls 1a apart, the pins 9:: are moved until they project through holes 30, thereby locking the frame and filter in place and at the same time providing an air-tight fit between the filter and the internal walls of the filter box portion of respirator 1. Thus, when the pins are pro jected. into holes 3c the frame and filter are locked in proper relationship with the filter box walls to assure a gas-tight connection.
In order to provide an air space between the internal walls of the filter receiving chamber portions and the filter, aplurality of rubberbeads 1b are integrally formed on the inner wall surfaces of the front wall 3 and rear wall 4 of the filter box portion and contiguous with sidewalls 1a, which beads extend along the entire length of the walls as well as across the upper arcuate bridging portion thereof as shown in Fig. 2. Thus, a bead is provided on each side of the triangle. An additional bead is also provided centrally along a portion of the height of the interior surfaces of both the front and rear Walls 3 and 4. However, these additional beads or ribs extend short of the apex of the triangular box.
In operation, after the filter 10 is folded over the filter-holding frame 9, as shown in Fig. 1, the filter frame and filter are pushed inwardly of the filter box portion of the respirator 1. The lower inturned edges 3b of sidewalls 1a are then spread apart and the filter assembly is pushed in farther until the pins 90 fit into the holes 31: of the respirator, thus assuring that the filter and frame have been pushed in far enough to form a completely air-tight seal betweentheframe and the filter, and between the filter and housing, particularly along the margin of the base of the frame. Thus, as air is inhaled, it enters, through ports 9a and 9b, and from the interior space of the frame, the air will move outwardly through the-front andrearfilter wall portions 10, thence 4. will move into the space between the filter and the walls 3 and 4, which are in communication at the tops or apex portions, and will flow through the ports 4a of the inhalation valve 4 as the wearer inhales. Meanwhile, the exhalation valve diaphragms 6 are held closed by inhalation.
As the wearer exhales,:air--cannot escape the inhalation valve 4 because it becomes seated, but does escape through the exhalation valves since diaphragms 6 become flexed outwardly from the position shown in Fig. 4 so as to permit air to escape outwardly through the ports 5a. Thus, dependence upon the judgment of the wearer as to how far the frame should be pushed into the box is avoided and an air-tight seal is assured.
Thus it will be seen that We. have provided an efficient respirator which provides minimum resistance to exhalation, therefore will avoid fatigue as the result of forced breathing; furthermore we have provided a reliable lock between the filter retainer and respirator in order to insure an air-tight seal between the retainer frame and filter and between the filter and housing, thereby insuring protection of the wearer against infiltration of noxious gases or dusts and preventing loosening and falling out of the frame even as a consequence of violet movements of the head of the wearer.
While we have illustrated and described a single specific embodiment of our invention, it will be understood that this is by way of illustration only, and that various changes and modifications may be made within the contemplation of our invention and within the scope of the following claims.
1. A respirator comprising a face piece for providing an air-tight seal around the nose, cheeks and chin of the wearer, a filter box of flexible material extending forwardly of said face piece and having closed sidewalls, a filter retaining frame having an outline corresponding to that of said filter box and supporting a filter folded over said frame, said filter box having a pair of holes, one on the lower end portion of each of said sidewalls, said filter retaining frame having integral pins emerging from the lower end portions of opposite sidewall portions, which pins are adapted to fit into said holes to retain said frame and filter in position in said box.
2. A respirator comprising a face piece portion of flexible material adapted to surround the nose, cheeks and chin of the wearer and a filter box portion of flexible material integrally formed forwardly of said face piece portion, said filter box portion having closed, downwardly and outwardly extending sidewalls and front wall and having a rear wall supporting an inhalation valve, a filter retaining frame having a filter folded thereover and shaped so as to closely fit in said box, said face piece portion having a bottom wall provided with a plurality of exhalation valves, a hole provided in the lower portion of each of said sidewalls, said filter retaining frame being of nylon and having integrally extending pins emerging from the lower ends of the sidewalls thereof, which pins are adapted to fit into said holes when the sidewalls of said box are pulled apart to retain said frame and filter in position within said box to insure an air-tight seal between the filter and box.
3. A respirator as recited in claim 2 wherein said inhalation valve comprises a cluster of holes in said rear wall and a flexible diaphragm secured only at its central point, centrally of said cluster of holes and onto said rear wall in confronting relationship with the nose of the wearer.
References Cited in the file of this patent UNITED STATES PATENTS