Respirator

March 22, 1938. n. schwartz 2,111,995

RESPIRATOR

Filed July 2, 1937

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Patented Mar. 22,1938

2,111,995

UNITED STATES PATENT OFFICE

2,111,995 RESPIRATOR

Nathan Schwartz, New York, N. Y.

Application July 2, 1937, Serial No. 151,629

Claims. (CL 128—146)

This invention relates to filter type respirators adapted to cover the nose and mouth of the wearer for the purpose of protection against dust, fumes, and noxious gases.

The object of this invention is to provide a simplified filter unit construction wherein thick or thin filter material may be accommodated, and also wherein any of the materials used for filters may be mounted, such as sponge, felt, etc.

Another object is to simplify the assemblage of the filter unit.

Another object is to facilitate the cleaning of the said unit.

Another object is to provide a displaceable filter 15 unit, wherein any of the parts may be readily removed and replaced at little cost.

Another object is to provide a large filter area with a small air space between the filter material and its supporting wall.

Another object is to provide a leak proof joint at the inlet port of the filter unit.

With these and other objects in view, the invention consists of certain novel features of construction as hereinafter shown and described 25 and then specifically pointed out in the claims.

In the drawing:

- Figure 1 is a section of the improved respirator in applied position.

Figure 2 is a front view of the filter unit.

Figure 3 is a perspective view of the clamps.

Figure 4 is an exploded view of the several layers composing the filter unit.

Figure 5 is a modified form of the device, in section.

Figure 6 is perspective view of the ring-clamp In the modified form.

Figure 7 is a back view of the filter unit in the modified form.

Figure 8 is a perspective of the plate in the 40 second form, illustrating the edge notches. The plate is shown partly broken.

Referring to the drawing by characters of reference, A designates the face piece of the respirator, B the filter unit, C the clamping device, D 45 the ring clamp device.

The face piece A is of molded elastic rubber material and is adapted to cover the nose and mouth of the wearer. It is the usual conventional type, being provided with a flutter valve, which 50 is also of conventional type. An aperture 10 is provided in the said face piece and is located in confronting relation to the mouth and nose of the wearer.

The filter unit construction is in two forms. 55 The first form is illustrated in Figures 1, 2, 3, and 4 and consists of a plate i i having an aperture 12, and a central forward protrusion 11. An elastic rubber washer 14 is located at the edge portion- of the forward side of the said plate II. The said washer has a recess 16 and has attached thereto a wire-mesh ~l S. The said attachment is secured by a proper fit between the said.wiremesh and the said recess, which proper fit consists of a tight hold upon the edges of the wire by the circumferential wall of the said recess. 10 This is accomplished by having the diameter of the wire-mesh a slight degree larger than that of said recess. Filter material IT is placed in confronting relation to the said wire-mesh and the said washer. A marginal ring (D) is 15 placed at the outer edges of the said filter material. Several resilient metal clamps C, preferably U-shaped are emplaced peripherally. Five such clamps are distributed evenly at the said periphery, whereby a leak proof joint is provided _:thereat, due to a squeezing action of the said' clamps upon the edges of the plate 11 and upon the said ring (D). That is, the said clamps are emplaced overlapping the said edges and the said ring and due to its comparative narrow size and t its resiliency, it provides a compression upon the said parts and thereby causes a leak proof peripheral joint.

The aperture 12 is connected with the aperture 10 by means of an eyelet 20, whereby communication is established between the face-piece of the respirator and the filter unit.

It will be noted that the wire-mesh acts as a support for the filter material. An air space It is formed between the plate 11 and the wire-mesh ; 15. The central protrusion 13 aids to maintain the said space. Space formation in this manner has several distinct advantages. The firmness of the wire-mesh under all conditions of moisture or fumes provides a constantly uniform space. 40 That is, there is no diminution of the space due to possible sa'gging of the filter material; such sagging may occur in felt, cotton, or sponge material when unsupported. Also, a comparatively small air space may thus be maintained; 45 minimizing the reinhalation of exhaled air. When corrugations of the plate are utilized for maintaining An air space, the numerous contacts with the filter material provide an impediment to the free flow of air. Therefore, breathing is 50 easier in the present arrangement. Another advantage is that a sponge filter may be used with a chemical neutralizing solution added thereon with the wire-mesh support arrangement herein described. Attention is called to the washer ar- 55

2,111,880 rangement. it is readily seen that the washer aids the formation of the said air space at the marginal area.

The second form of this invention is illustrated 6 in Figures 5, 6, 7, and 8. The plate Ha has an aperture ί2α, a central protrusion 13α, and a marginal curve 19 which is directed forward and outward. The aperture 12α of the plate connects with the aperture 10 of the face-piece A of the 10 respirator. An eyelet 20 is used to make the said connection, whereby communication is established between the face-piece and the filter unit. Filter material Π is mounted between the edges of the plate Ha and a ring-clamp 21. A wire IS mesh I Sa is placed at the rear side of the filter material and it abuts the marginal end 19 of the plate Ha and it also abuts the protrusion 13α whereby a space 18α is formed.

The elastic rubber washer is not shown in this 20 form, but it may be adjusted in the manner described in the first form. But this form is quite practical without it, especially so if the respirator is used in light duty work.

The ring 21 is preferably of a substantial, rigid, 25 metallic construction and preferably wire shaped.

It has attached by means of solder six resilient wire prongs 22 which extend rearward. Three notches 23 are provided at the inner side. The circumferential diameter of the prong area is less 30 than the plate area. However, due to the resiliency of the said prongs, they are slipped over the edge 24 of the plate I la with ease. The edges 24 are provided with notches 25. The positions of the notches 25 correspond to that of the prongs 35 22. The prongs 22 are therefore positioned to embed in the said notches 25 and when the said embedding is adjusted at the notches 23, an interlocking arrangement occurs. That is, the prongs are fastened, or anchored, and cannot 40 move forward, backward, nor sidewise.

A wire span 26 is located at the rear side of plate Ila which is for the purpose of providing additional firm support for the ring-clamp. As illustrated in Figures 5 and 7, the wire span 26 is 45 wound about the rear portion of the prong 22.

That is, the wire is wound around two prongs located opposite each other. While the wire is intact the ring clamp is not removable. However, the filter material and its wire mesh support are 50 removable. The method of attaching wire spans are simple; one end of the wire is wound at the rear portion of a prong and the other end of the wire is wound to the rear portion of an opposite prong with a moderate degree of tightness. To 55 make the ring-clamp removable for cleaning or replacement purposes, the wire must be removed first. If desired two or three such wire spans may be applied. That would add greater security to the firmness of the structure and would be re00 quired only in extremely heavy duty work.· If additional wires are added, they are to be applied as per description for the one wire attachment.

It is to be noted that the filter material is re65 movable in the second form without removing any other part of the filter arrangement. That is, the clamp arrangement is such that it remains intact without a filter material inclusion. Therefore the used filter material may be re70 moved and a new one inserted. The removal is practical by a direct pull from without or by pressing thereon from within through the aperture 12α.

It is to be noted that the U shaped clamps C are 76 shown as having a short and a long arm and as a wide U with rather short arms. However, in practice the size and shape may vary to suit the precise needs, for example, a substantially v shaped clamp may at times be more readily adjusted than a u shaped one.

It is also to be noted that the U shaped clamps C may be permanently attached to the ring-clamp D by means of solder. This arrangement may be preferred when greater firmness of the clamping arrangement is desired for heavy duty work, io One clamp C is illustrated so attached in Figure 4. In this manner of clamp arrangement, the filter material may be removed independently of the rest of the marginal layers, and a new one inserted thereat. ₁₅

It is to be noted that cleanliness of the filter unit marginal portion is easily maintained in the improved device, because the clamps and all parts of the marginal layers are displaceable and replaceable. Advantages of the older methods 20 therefore are obvious, namely, when threading devices are used in plants where chemical fumes are present, such devices may erode and thereby permit leaks at the filter material marginal attaching joint. When grooves are utilized for 25 filter attachments, dirt may accumulate thereat. In paint, shellac, glue, varnish and plaster works where the substances are sticky, the cleaning operation is difficult. In woolen works anthrax or other germs may collect in the grooves or in 30 the threads, and antiseptic applications are not easy to apply, while in the improved displaceable device herein described such antiseptic applications may readily be applied to every portion of the said marginal layers of the said filter unit. 35

It is to be noted that the elastic rubber washer has a very important function in the improved respirator. Its elastic compressibility provides a needed function, namely, to choke and seal the joint between the filter material and the metallic 40 plate edge. The action is caused by the function of the said elastic rubber in filling in irregularities contained in the metal and also in the filters. All metals and filter elements have irregularities. If they have none, they soon obtain some while in 45 use. The extraneous substances in the workshop are usually such as to attack the metal or the filter element and thereby cause irregularity in the filter element and erosion or irregularity in the metallic edge.