Title:  Protective breathing mask

United States Patent:  5,875,775

Assignee:  Duram Rubber Products (Ramat Hakovesh, IL)

Filed:  April 9, 1997

An improved protective breathing mask comprising fire-resistant stretchable material shaped as a hood for wearing over and enclosing the head. An access opening allows the head to be placed therethrough such that a substantially airtight closure is provided at the neck. The mask includes a visor and filter materials sealed to the stretchable material. The improvement to the basic mask construction is a breathing adaptor provided on the interior side of the mask face, which encloses a one-way respirator. The breathing adaptor maintains the mouth and nose spaced apart from the filter, and efficiently directs breathing efforts to equalize inhalation airflow via substantially all of the filter, while the one-way valve eases exhalation airflow and reduces condensation on the interior side of the visor. Thus, filter utilization is improved and the filter protection time is extended, for increased safety.

SUMMARY OF THE INVENTION

Accordingly, it is a principal object of the present invention to overcome the above-mentioned difficulties by provision of protective breathing apparatus for fire, health and toxic air emergencies. It is another object of the invention to provide a convenient, lightweight, affordable, fire-resistant and instantly available gas mask for protection against toxic air.

In accordance with a preferred embodiment of the invention, there is provided an improved protective breathing mask having fire-resistant stretchable material of not less than about 300% stretchability shaped as a hood and having an access opening through which the head is placed for wearing the mask over the head and enclosing it such that a substantially airtight closure is provided at the neck, said stretchability inherently providing, without ancillary tightening means, a minimum unoccupied interior volume of said hood such that, upon donning, the inrush of surrounding toxic air is minimized, at least a portion of the mask providing a transparent viewing area for the eyes, a mouth location of said stretchable material being replaced by a filter having materials sealed thereto including a plurality of fire-resistant flexible layers at least one of which is an activated cloth having activated charcoal fibers in the form of woven or non-woven cloth, wherein the improvement comprises:

breathing adaptor means comprising a flexible material within the mask interior enclosing at least the mouth and maintaining spaced apart therefrom a one-way respirator and the filter, said breathing adaptor means providing uniform inhalation airflow via substantially all of the filter, while easing exhalation airflow via said one-way respirator.

In the basic mask construction, a combination of stretchable and fire-resistant materials are employed in a hood-like construction providing viewing and breathing protection features. The combination of materials also provides the mask with particularly advantageous features suited to portability, compactness, and instant availability, which are achieved by its lightweight, flexible construction.

The hood-like construction may be fabricated by a molding or dipping process, providing a seamless enclosure with front and back panels, and a bottom edge which is formed with an access opening to the airtight interior volume enclosed by the mask. The access opening can be pulled apart to enable the user to quickly and easily slip the entire mask over the head.

In addition, the access opening is shaped so as to fit snugly around the user's neck, providing a substantially airtight closure without the aid of an additional closing device. The contour of the mask is designed to reduce "dead space" and provide the minimum interior volume needed for wearing over the head. This design minimizes the inrush of surrounding toxic air when the access opening is pulled apart by the user, in donning the mask.

Portions of the material in the front panel of the mask are removed and are replaced at eye and mouth locations by fire-resistant transparent and filter materials respectively providing viewing and breathing capabilities. The properties of these materials are uniquely suited to the life-saving functions they perform, in enabling the user to maintain his vision and breathing while making his way to safety in fire, gas and toxic air emergencies.

For the viewing portion of the mask, the transparent material is a high-temperature resistant and fire-retardant thermosettic material which does not melt even on contact with a flame. The filter material is provided in portions of the mask to either side of the nose so as to maintain good airflow distribution. Fabricated from a combination of materials provided in several layers, each of the filter materials has a distinct function. For example, three layers of active charcoal cloth are interleaved with two layers of a particle filter. The activated charcoal cloth layers serve to eliminate poisonous gases and acids from the air and the remaining layers provide an air filter to eliminate airborne particles.

A feature of the invention is the overall shape of the mask which is appropriate for most head sizes, without interference from scalp hair. The viewing and filter materials are designed to cover a maximum surface area of the front panel of the mask, making it suitable for many users despite a wide variation in head and neck sizes.

The improvement to the basic mask construction is a breathing adaptor provided on the interior side of the mask face, which encloses a one-way respirator. The adaptor efficiently directs breathing efforts to equalize inhalation airflow via substantially all of the filter, while the one-way valve eases exhalation airflow and reduces condensation on the mask interior viewing portion. Thus, filter utilization is improved and the filter protection time is extended, for increased safety. The breathing adaptor can be provided as a mouthpiece or it may be shaped to encompass the perimeter of the filter.

Claim 1 of 15 Claims

We claim:

1. An improved protective mask having fire-resistant stretchable material of more than about 300% stretchability shaped as a hood and having an access opening through which a head of a user can be placed for wearing the mask over the head and enclosing it such that a substantially airtight closure is provided at the neck, said stretchability inherently providing, without ancillary tightening means, a minimum unoccupied interior volume of said hood such that, upon donning, the inrush of surrounding toxic air is minimized, at least a portion of the mask providing a transparent viewing area for the eyes, a mouth location of said stretchable material being replaced by a filter having materials sealed thereto including a plurality of fire-resistant flexible layers at least one of which is an activated cloth having activated charcoal fibers in the form of woven or non-woven cloth, wherein the improvement comprises:

breathing adaptor means comprising a flexible, porous material having a slight airflow resistance and being mounted within the mask interior capable of enclosing at least the mouth of the user and maintaining spaced apart therefrom a one-way respirator and the filter, said one-way respirator having a cracking pressure slightly lower than said airflow resistance, said breathing adaptor means providing uniform inhalation airflow with a low pressure drop via substantially all of the filter and said flexible, porous material enclosing at least the mouth, while easing exhalation airflow by directing it so as to minimize passage thereof through said flexible, porous material, causing substantially all of said exhalation airflow to flow via said one-way respirator.

____________________________________________
If you want to learn more about this patent, please go directly to the U.S. Patent and Trademark Office Web site to access the full patent.