Protective hood

July 30, 1957

R. MONRO

2,800,901

PROTECTIVE HOOD

Sheets-Sheet 1

Filed May 6, 1953

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INVENTOR.

Randolph Monro BY Λ .

July 30, 1957

R. MONRO

2,800,901

PROTECTIVE HOOD

Filed May 6, 1953

Sheets-Sheet 2

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2,800,961

Patented July 30, 1957

United States Patent Office

2,800,901

PROTECTIVE HOOD

Randolph Monro, Joppa, Md.

Application May 6,1953, Serial No. 353,435

Claims. (CI. 128—141) (Granted under Title 35, U. S. Code (1952), sec. 266) it is desired to clearly state the precise problem in this art which my invention eliminates. Heretofore, persons required to remain without shelter in adverse climatic conditions of sub-zero temperature, especially when ac5 companied by high wind, altnough able to provide themselves with adequate protection for their bodies and heads, have not been able to provide adequate protection for their faces. The conventional, weather protection consists of a parka hood adjusted to extend forward 10 around the face, and additional thermal insulation, such as weather masks, knitted helmets, mufflers and the like. These devices are inadequate because they do not provide protection for the eyes and the adjacent portions of the face against cold wind, and moreover, the danger of frost15 bite is present due to the ability of the wind to penetrate the folds thereof, and due to the possibility of the folds becoming fouled with frozen moisture from exhaled breath. In any event, the angular range of vision is restricted because of the need for adjusting the portion of 20 the parka hood so as to shield the face from the wind.

Even with the best existing means for thermal protection of the face it is necessary for a man walking against the wind to turn his head to one side to the point whereby his vision in the direction in which he is moving is severely 25 restricted. Conventional gas masks with an integral nosecup, which prevents exhaled air from reaching the lenses, could be used to provide some weather protection and insure a wider field of vision when used in conjunction with a parka hood, were it not for the fact that the lenses 30 of the eyepieces become chilled to below the dew point and thereby freeze moisture on the inner surface of the lenses that has evaporated from the wearer’s face. In some types of protective masks, a moisture absorbent, inner lens is inserted behind the facepiece lens to prevent 35 the accumulation of moisture thereon. While this is of some aid, it has been found that the moisture absorbent capacity of such inserts is limited to a shorter period of time than the wearer ordinarily may have to wear his mask and that the inserts have to be replaced frequently.

Other drawbacks inherent in using a conventional gas mask along with a parka hood are: (1) the outlet valve tends to become inoperative due to freezing of exhaled air moisture in the valve, and (2) when the temperature goes below —20° F. for over an hour, the face of the 45 wearer is in danger of freezing due to the fact that the gas mask facepiece is a good thermal conductor and therefore offers little weather protection. It is apparent that to solve this problem it is necessary that a device be provided which will: (1) prevent the eyepiece lenses from 50 becoming frosted or fogged without repeated renewal of any part of the assembly, and (2) provides thermal insulation for the face of the wearer without appreciably impairing his range of visibility.

Referring particularly to Fig. 3, a human subject is 55 shown wearing a conventional gas mask 10. The parts of this mask, all of which are conventional, are facepiece 12, having an integral nosecup (not shown) inside nose protuberance 13, lenses 14, which are secured to the facepiece by eyerings 16, outlet valve assembly 18, can60 ister socket 20 and head harness 22. The improved protective hood comprises outer wall 24, which is made of an impermeable material, such as a coated fabric, and is substantially globular in configuration, and which terminates in a cape 26, which is adapted to cover the upper portion of the body of the subject. A draw cord 28 is positioned by tabs 30, which are secured to the outside of wall 24, in the vicinity of the neck portion of the hood, and is adapted to be adjusted by slide lock 32, which is accessible from the front of the hood. In Figs. 1 and ⁷⁰ 2 it will be seen that straps 34 are secured to the rear portion of cape 26 and pass under the arm pits of the

The invention described herein may be manufactured and used by or for the Government of the United States of America, for governmental purposes without the payment to me of any royalty thereon.

This a continuation-in-part of my application Serial No. 642,772 filed January 22, 1946 now abandoned.

The invention relates generally to protective clothing and specifically to a hood to be worn in conjunction with a gas mask in low temperature zones.

It is an object of this invention to provide a protective hood for use in sub-zero temperatures which permits the conventional type of protective mask designed primarily for use in warm climates to be used in conjunction therewith.

It is another object of the invention to provide a protective hood to be used in sub-zero temperatures in conjunction with a conventional type of protective mask, such as a gas mask, wherein the lenses of the protective gas mask are free of fogging and/or frosting.

It is still another object of the invention to provide a protective hood for use in sub-zero temperatures in combination with a conventional, protective mask, wherein the hood is provided with lenses and additional structure for securing the hood to the eyepieces of the mask to thereby hold the hood lenses in position and to insulate the eyepieces of the mask from the atmosphere.

It is a further object of the invention to provide a protective hood for use in sub-zero temperatures in conjunction with a conventional mask, wherein structure is provided for preventing moisture from collecting on the interior portions of the hood, thereby avoiding freezing thereof and stiffening of the hood.

It is a still further object of the invention to provide a protective hood for use in sub-zero temperatures in conjunction with a conventional, protective mask, wherein structure is provided for preventing freezing of the mask, specifically its outlet valve structure.

It is a specific object of this invention to provide a protective hood for use in sub-zero temperatures in conjunction with a conventional, protective mask, the combination of which will function satisfactorily under conditions as extreme as when the ambient temperature is —65° F. in a 10 mile an hour wind (a 2500 wind chill factor).

The above and other objects will become more apparent from the following specification taken in connection with the accompanying drawings, which illustrate a preferred form of my invention, wherein: Fig. 1 is a front view in elevation of my protective hood. Fig. 2 is a side view in elevation of the protective hood. Fig. 3 is a sectional view taken on line 3—3 of Fig. 1, with the subject and the conventional, protective mask shown in elevation. Fig. 4 is a front elevational view of the hood with portions broken away. Fig. 5 is a sectional view taken, on li_ne 5__5 _of Fig. 3. Fig. 6 is a vertical, sectional view taken through the eyepiece portions of the protective hood and the conventional, protective mask.

Prior to describing the structure of the preferred form,

2,800,901

-· - wearer and snapped onto the front portion of the cape 26 to thereby secure the hood in place. Outer wall 24 has lens openings, to be subsequently described, and canister opening 27 (see Fig. 4) formed therein. The improved hood also comprises globular, inner wall 36. made of impermeable material, which has' at least one opening 37 formed therein at a point which is to the rear of the wearer’s neck, and is attached to outer wall 24. by stitching 38. It is important to note that the stitching 38 forms an oval seam 41 that extends entirely around the hood at approximately the jaw-line level (see Figs. 1, 2 and 3). Hood walls 24 and 36 inclose the head of the wearer and the conventional gas mask 10 except for the lenses 14 (see Figs. 1, 2 and 4). Inner wall 36 has lens openings, to be subsequently described, canister opening 35 (see Fig. 4) and opening 39 for receiving outlet valve assembly 18 (see Fig. 3).

The outer wall 24 has a portion 25 in the vicinity of the lower front of the hood which forms snout-like ice pocket 40. In this regard it should be noted that portion 25 extends downwardly to point 46, where it is folded, then upwardly to the point where it is joined to the part of outer wall 24 adjacent the chin of the wearer. The portion 25 overlaps onto itself at its sides and is stitched at these points to form seams 47. Baffle 42 is secured to inner wall 36 by stitching 44 and hangs vertically downwardly within the ice pocket to a point short of: the bottom extremity 46 of said ice pocket (see particularly Fig. 3). The lower portion of baffle 42 is secured at its sides to portion 25 by seams 47 (see Fig. 3). Elongated, rectangular, wire rings 48 and 50 are attached to the portion 25 of outer wall 24 and to the baffle 42 by stitching 49 and perform the function of keeping said portion and baffle spaced apart (see Figs. 3 and 5). A conventional waterproof slide fastener 52 having a pull cord 54 is mounted near the bottom of the ice pocket 40.

From Figs. 1 and 2 it will be seen that conventional gas mask canister 56 is accessible to the atmosphere. The neck of the canister 56 passes through opening 27 in the outer wall 24 and opening 35 in the inner wall 36, and is secured in the canister socket 20 of the gas mask 10 in the conventional manner. The portions of the outer wall 24 surrounding opening 27 and inner wall 36 surrounding opening 35 may be stitched together, and are tightened snugly around the canister 56 or its neck in a conventional manner to thereby seal the opening from the atmosphere.

Both the outer wall 24 and the inner wall 36 are.provided with the previously mentioned lens openings which are adapted to be aligned with the lenses 14 of the con- ¹ventional gas mask and thereby provide a clear line of vision for the wearer. By referring to Fig. 6 the specific structure may be understood. Inner wall 36 is provided with eyeholes which are defined by reinforced rims 56, which are adapted to be seated upon eyerings 16 of the conventional mask 10. The outer wall 24 is provided with eyeholes that are defined by reinforced rims 58 which are positioned in front of the eyerings 16. Positioned between the outer wall 24 and the inner wall 36 cord until prevents the coldness from being transmitted to the lens 14 of the mask. This lens structure has proved to effectively prevent fogging or frosting of the inner lens 14 and is one of the major advantages of my invention.

Prior to donning the gas mask or other protective mask, the protective hood is fitted over the conventional mask with the reinforced rims 56 of the hood positioned upon the eyerings 16 of the mask, the outlet valve assembly 18 positioned within the opening 39, and the neck of canister 56 positioned within the openings 27 and 35 of the hood, and secured in canister socket 20 of the mask. This assembly is then donned by the wearer, the head harness 22 being adjusted as needed. The draw 28 is then drawn around the neck of the wearer exhalation resistance is increased appreciably, and then fixed in this position by the slide lock 32. With the cape 26 positioned about the shoulder of the wearer comfortably, the straps 34 are then extended under the armpits of the wearer and secured to the cape 26 in a conventional manner.

With the foregoing protective device donned, the wearer is free to operate under the adverse conditions previously set forth in the objects of this invention. The operation of the protective device is as follows: air is inhaled into the canister 56 where it is purified in the conventional manner, drawn through the canister socket 20 of the mask and into the space between the wearer’s face and the facepiece of the mask from which it is inhaled into the lungs of the wearer. The manner in which the inhaled air is channeled on the interior of the conventional mask depends upon the type of mask used; ordinarily some of the inhaled air is directed against the inside of. the mask lenses 14 to aid in preventing fogging . thereof. Upon exhalation, air is forced through the outlet valve assembly 18 and passes downwardly behind the baffle 42 in the ice pocket 40, then upwardly in front, of said baffle into the air space 68, defined between the inner and outer walls of the hood, it being understood that the air space 68 completely surrounds the head and face of the wearer at the front, top, rear and sides, above the seam 41 formed by stitching 38. The path of the exhaled air is indicated by the unnumbered arrows in Figs. 3 and 4, where it will be observed that when the air reaches the opening 37 in the inner wall 36 it passes into air space 45 70 defined by the inner wall 36 and the lower portion of outer wall 24 (that portion below seam 41), and the head of the wearer and the conventional mask, the latter being completely surrounded above the draw cord 28. The exhaled air then leaves the air space 70 via the re50 stricted annular opening defined by the cape 26 and the neck of the wearer. From this description it will be apparent that the interior of the hood is under a positive pressure produced by the exhaled air, and that there is ordinarily a flow of air from within the hood out under 55 the cape 26 to the atmosphere. It will also be observed from the above description that most of the head and face of the wearer is surrounded by two layers of relatively warm air, the air in spaces 68 and 70, and that a con____________________ siderable amount of thermal insulation is thereby proin the immediate vicinity of each lens is a substantially 60 vided.

annular fabric member 60 which is secured to both of -......- --said walls by stitching 62. Each annular member 60 is provided with an eyehole defined by a reinforced rim 64 which is positioned between an eyering 16 and an eyehole rim 58. / ’ ’ eyehole rim 58 of the outer wall 24 and the eyehole rim 64 of its associated annular member 60. With the composite lens structure illustrated in Fig. 6, it will be apparent that when the hood is mounted on the wearer of _______________—„ a conventional mask and the rims 56 of the hood posi- 70 without obstructing the passage of exhaled air tioned on the eyerings 16 of the mask, that an insulating layer of air is formed between each lens 14 of the mask and its associated lens 66 of the hood. It should be noted that each lens 66 of the hood is insulated from -------r—- „ „„ _{tuat uuluure uum anQ rea}r its associated eyenng 16 of the mask by a rim 64, which ⁷⁵ thereof are exposed to the sub-zero temperatures, and

-----jpuvcc w ariu. ZU, dUU lUciL a, UUllsiderable amount of thermal insulation is thereby proOne of the salient features of the improved mask is the novel ice pocket : 40. The ice pocket 40 presents a relatively large area to the sub-freezing temperatures. Since the exhaled breath is forced to traverse the passageA plastic lens 66 is positioned between each 65 ^way formed in the ice pocket by .the baffle 42, any moiso ., ... j,_Jre contained therein tends to condense and freeze on the inner surface of the ice pocket 40. The size and shape of the ice pocket is such that a considerable amount of moisture can be condensed and frozen in the ice pocket - _ -------.-------- When a sufficient amount of ice has: accumulated within the ice pocket access to the interior of the ice pocket is had by opening the slide fastener 52, and the ice is removed. The ice pocket is designed so that both the front and rear

2,800,901 thereby operates at maximum efficiency. Should this protective hood be worn at higher temperatures, the efficiency of the ice pocket will necessarily be reduced and some moisture from the exhaled air might find its way into the air space 68. This moisture will condense and drain downwardly into the air space 68 until it reaches the seam 41, and then it will drain downwardly and forwardly along the seam 41 into the ice pocket 48, instead of entering the air space 79 and draining down the neck of the wearer.

The above described embodiment of my invention may be modified without departing from the true essence of the invention. For example, the hood which ΐ have described operates as a positive pressure, leakproof-type hood. It has been constructed to be used with a parka hood up, but it can be readily altered to operate as a neutral pressure, non-leakproof hood and be used with a parka hood down. In the preferred form illustrated, the opening 39 fits tightly around the outlet valve assembly 18 of the mask 10 to insure that the exhaled air is forced into the ice pocket 40, through the air spaces formed between the walls of the hood, and out from under the cape 26 under sufficient pressure to prevent contaminated air from entering into the hood from under cape 26 and reaching the outlet valve assembly or the face to facepiece seal, which are the two most vulnerable areas of the assembly with respect to leakage from the atmosphere into the interior of the mask. To change this positive pressure, leakproof-type hood into a neutral pressure, non-leakproof hood, it is simply a matter of opening the ice pocket, by moving the slide fastener 52, or making other minor adjustments. Furthermore, the invention may be readily adapted so as to be usable with any type of military or industrial gas masks, for example, a facepieceless assembly wherein inhaled and exhaled air is directed through an industrial type of nosecup. The specific setting disclosed in the preferred embodiment was selected because of the proven efficiency of the specific components under arctic conditions.

Having described my invention in great detail, it is desired to particularly point out what I consider to be my contribution to this art. I have provided an improved protective hood which may be used in conjunction with any of the conventional types of protective masks, which is particularly adapted for use in sub-zero temperatures, wherein structure is provided for eliminating or minimizing to a great extent the formation of frost or fog on the lenses of the mask, and wherein a substantial amount of thermal insulation is provided about the head and face of the wearer without impairing his range of visibility to any appreciable extent. Specifically, my improved, protective hood has proved satisfactory when worn indefinitely in an ambient temperature of —65° F. in a 10 miles per hour wind (2500 wind chill factor).

Although I have described one embodiment of my invention in great detail, it is not thereby intended to limit it to the precise structure shown, but it is intended to 60 embrace all changes that might be made by one skilled in the art which wall within the spirit of the invention or the scope of the appended claims.