Apparel – Guard or protector – For wearer's head
Patent
1997-10-02
2000-05-02
Neas, Micheal A.
Apparel
Guard or protector
For wearer's head
2 8, A41D 1300, A61F 906
Patent
active
060556668
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a face shield intended to be placed before the face of a wearer, components for such a face shield and a method for reducing the mixing of exhalation air in the inhalation air in such a face shield.
DESCRIPTION OF THE RELATED ART
During work such as welding and mechanical processing, face shields are required in order to prevent the eyes and face being subjected to ultraviolett light, heat, toxic substances, particles or other factors which can cause damage to these body parts.
For a long time it has been a problem in work where face shields are used that the wearer often suffers from fatigue, headaches and dizziness. The causes of this have been shown to be, amongst others, an increased carbon dioxide content in the inhalation air of the wearer when face shields are used. Experiments have shown that the inhalation air behind a face shield has an increased carbon dioxide content because of the mixing in of exhalation air. There are both limits and recommendations for the permitted content of carbon dioxide in inhalation air.
Mechanical measures for blowing away welding smoke from in front of a welding screen through sucking air from the inside of the welding screen and in this way producing an increased air circulation in front of the welding screen, have been taken in the American Patent U.S. Pat. No. 5,029,342, which shows a welding screen comprising a fan which is driven by solar cells. The fan sucks air from the inside of the welding screen and out through the front surface of the welding screen in a direction towards the welding place with the intention of preventing smoke from reaching the welding screen. The disadvantages of this construction are that, in order to achieve an effective blowing effect, a relatively large amount of air is required which causes draughts inside the welding mask and that the airflow through the fan is regulated by the welding light and not according to the ventilation requirements that the wearer has.
The prior art also includes the American Patent U.S. Pat. No. 2,377,122, in which a welding helmet is shown in the form of a separable cover, which is placed over the head and shoulders of the wearer. A breathing mask covers the nose and mouth, whereby inhalation air is led from air intakes at the upper back part of the welding helmet to the mask via two hoses. There is a non-return valve by each of the air intakes, which opens so that air can be sucked in through the hoses. Exhalation air is led out from the breathing mask through a non-return valve in the face mask and out through the front surface of the welding helmet via a nozzle. The disadvantages in this construction are the large breathing resistance which the inhalation air meets through the hoses, which means that it becomes strenuous for the wearer to breathe, and that a volume of exhalation air is supplied to the breathing mask during exhalation where-by the carbon dioxide content increases in the inhalation air in the subsequent inhalation. Further disadvantages are moisture problems, the risk of allergies and the feeling of discomfort which the wearer can experience when a breathing mask is placed over the nose and mouth for a long time.
A problem with high head temperatures and fogging of the visor occurs in integral helmets for use in e.g. motorcycling or the like. Owing to this there is a suggestion in U.S. Pat. No. 4,704,746 to ventilate an integral helmet with the help of the relative wind which occurs during travel on e.g. a motorcycle. A front channel communicates on the one hand with the inside of the helmet via openings, on the other hand with the outside of the helmet via an opening which is provided with an adjustable valve. In a first ventilation position, air is supplied to the helmet from the outside of the helmet via the front channel. In a second ventilation position, the valve is struck by the relative wind, whereby an underpressure occurs in the front channel. Consequently, air is sucked out from the inside of the helmet through the fron
REFERENCES:
patent: 2377122 (1945-05-01), Bakke
patent: 2388604 (1945-11-01), Eisenbud
patent: 3232290 (1966-02-01), Nicolai
patent: 3438060 (1969-04-01), Lobelle et al.
patent: 3838466 (1974-10-01), Poirier
patent: 3868726 (1975-03-01), La Marre et al.
patent: 4101979 (1978-07-01), Tarrone
patent: 4514864 (1985-05-01), Huber
patent: 4704746 (1987-11-01), Nava
patent: 5029342 (1991-07-01), Stein et al.
patent: 5031237 (1991-07-01), Honrud
Eklund Jorgen
Mases Kjell
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