Apparel – Guard or protector – For wearer's head
Reexamination Certificate
2002-12-12
2004-08-10
Welch, Gary L. (Department: 3765)
Apparel
Guard or protector
For wearer's head
C002S436000
Reexamination Certificate
active
06772448
ABSTRACT:
BACKGROUND OF THE INVENTION
The problem of fogging of sports goggles has been known for many years. In ski goggles this effect takes place when the temperature on the interior of the lens reaches the dew point from the combination of cooling of the lens in contact with the cold air outside, and the flux of moisture from the face into the interior air volume. The fundamental concept to reduce fogging in goggles is to achieve an air temperature in the goggle above the dew point at the surface of the inner lens. The counter actions are to add heat and remove moisture from the interior of the goggle. Attempts at making non-fogging goggles are quite numerous and typically rely on a variety of different techniques.
The following are some examples:
Electric heating of the lens.
Increasing the thermal insulation capability of the lenses by using two lenses with an air gap between them. This reduces the heat flow through the lens and subsequently allows the inner lens surface temperature to come closer to that of the skin surface, thus raising the inner lens temperature above the dew point in the goggle.
Increasing the radiant heat trapping of the goggle lens by coating the surfaces of the lenses facing each other and the outer surface with infrared reflective and low emissivity films. This reduces the lens radiation heat transfer losses. Again this technique subsequently allows the lens surface temperature to be closer to that of the skin surface, thus raising the temperature of the inner lens surface above the dew point in the goggle.
Increasing the radiant heat transfer from the skin to the inner lens, by choosing or coating the inner lens with an infrared absorbing layer on the inner-facing surface of the inner lens. This maximizes the radiant heat transfer from the face to the inner lens, thus allowing the inner lens surface temperature to be closer to that of the skin surface, and raising the temperature of the lens above the dew point in the goggle.
Increasing the air gap between the inner and outer lens. This further decreases the heat loss through the lens and subsequently allows the lens surface temperature to be closer to that of the skin surface, thus raising inner lens surface temperature above the dew point in the goggle.
All three of the thermal insulation techniques mentioned above alone does not result in defogging the goggle because the air just above the surface of the skin and eyes is close to 100% relative humidity and the insulation is not perfect. Thus, the lens is colder than the skin surface and condensation will occur as water diffuses from the skin surface to the lens. Therefore using a thermally resistant lens needs to be coupled to a means of removing the moisture from the skin surface and the volume of air in the interior of the goggle.
The following are several techniques of flowing air into a goggle and transferring heat by airflow:
Use metal foils inside the goggle to transfer heat from the top of the goggle, in which the warmer and lighter air rises, to the incoming air in the bottom of the goggle.
Use various vents that draw or force air through the goggle while the skier is moving.
Heat exchange between incoming air and the outgoing air.
Use a fan to draw air through the goggles.
Use adjustable apertures or lift the face pad to increase or decrease air flow.
The following are techniques to condense water or absorb water vapor in the interior of the goggle:
Use metallic conductors to provide condensation areas inside the goggles.
Use thin lens areas of high heat transfer that condense water.
Use chemical absorbents in a liner on the sides of the lenses, or the lenses themselves, to absorb moisture.
In general, the above techniques are either ineffective in achieving a satisfactory non-fogging effect in the full range of ski conditions or are costly and complex in commercial products.
U.S. Pat. No. 2,612,639, Christensen et al.; “Closed Goggles Structure”, describes heat exchangers and condensers for circulation of air and dehumidification. They mention using direct air contact with the face to heat the air in the eyecup cavities. They claim a use of high thermal conductivity material in the condensers, but they do not mention using the high thermal conductivity elements to conduct heat from the user to the air.
U.S. Pat. No. 2,615,162, Christensen et al.; “Cold Weather Goggles”, describes using condensers and heat exchangers with closed air circulation in a goggle. They do not describe using heat from the user though conductors to heat the air in the eyecup cavities.
U.S. Pat. No. 2,618,782, Christensen et al.; “Goggles Structure”, describes forming inlets and outlets of material of high thermal conductivity. Uses the conductivity of the inlets and outlets to dissipate the heat from the top of the goggle to reduce “the absorption of moisture of air in the eye cup cavity”. This patent also describes insertable air passage-ways: “Although the above outlet structures are formed of flexible copper or other thin metallic conductor material, it will be apparent that rubber or plastic adaptation of this model can be constructed for insertion with the goggles frame.” This patent does not describe using the heat conducted from the body to heat the inlets or outlets.
U.S. Pat. No. 2,619,643, Christensen et al.: “Cold Weather Goggles”, describes using metal heat exchanger to condense the moisture and simultaneously dry and heat the incoming air. They do not mention heating the incoming air through the frame to avoid fogging, nor do they describe using heat transfer from the face contact to the air passages.
U.S. Pat. No. 3,591,864, Allsop: “Nonfog Goggles”, describes a double lens for goggles, with a flexible woven wire mesh of high thermoconductivity in the frame. The mesh keeps snow out but is loose enough that moisture condenses.
U.S. Pat. No. 4,290,673, Yamamoto; “Ski Goggles”, describes double lens goggles with the space between the lenses being heat insulating. Inner lens has an air port at one end close to the frame and a water-repellent air-permeable filter opposed the air port. No references to wicking or heating incoming air.
U.S. Pat. No. 4,317,240, Angerman et al.; “Sports Goggle”, describes a single lens goggle with a dual frame design with improved ventilation characteristics.
U.S. Pat. No. 4,584,721, Yamamoto; “Device for Use in Helmet for Preventing Fogging by Electric Heating”, describes a transparent electroconductive film in the lens used to generate heat with the passing of electric current.
U.S. Pat. No. 4,370,914, Harris; “Eye Protectors”, describes goggles with frames comprising rearwardly angled cowls to improve ventilation characteristics.
U.S. Pat. No. 4,707,863, McNeal; “Anti-Fog Goggle with Foam Frame”, describes goggles with foam frame with air channels incorporated to improve ventilation characteristics.
U.S. Pat. No. 5,018,223, Dawson et al.; “Non-Fogging Goggles”, describes double lens goggles with a vacuum-deposited metal coating film on the outer lens. Body heat radiated through the metal film serves to lower the temperature differential between the outside and the inside of the goggles.
U.S. Pat. No. 5,452,480, Ryden; “Ski Goggles”, describes a fan used to exhaust air from the air space between the goggles and a user's face in order to improve ventilation characteristics.
U.S. Pat. Nos. 5,363,512 and 5,542,130, Grabos, Jr. et al.; “Protective Goggle and Lens with Adjustable Ventilation”, describes goggles with adjustable ventilation ports in the frame with a shutter.
U.S. Pat. No. 5,652,965, Crooks; “Non-Fogging Goggles”, describes goggles with screened and unrestricted air ports, which control the amount of air passing through the goggles.
U.S. Pat. No. 5,689,834, Wilson; “Goggles”, describes heat sinks used in the goggle structure to dissipate heat inside the goggles. Additional air ventilation ports are disclosed.
U.S. Pat. No. 6,049,917, Ryden; “Air Injection Sports Goggle and Method”, describes a ventilating fan on the top side of a sport goggle which pulls air in through an air injection hole to improve ventilation
Bradford Zachary
DeJohn Marc D.
Hockaday Robert G.
Navas Carlos J.
Turner Patrick S.
Energy Related Devices, Inc.
Welch Gary L.
LandOfFree
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