THERMAL GOGGLE LENS ASSEMBLY WITH EXTERNALLY VENTED

CHAMBER

TECHNICAL FIELD

[001] This invention relates to thermal goggles and, more particularly, to double lens goggles.

BACKGROUND OF THE INVENTION

[002] Goggles used for skiing tend to fog due to the low environmental temperature and the high humidity of the air captured between the goggles and a user's face. Fogging may be avoided by using goggles having inner and outer lenses defining an air cavity therebetween. The air cavity insulates the inner lens from the environment such that it does not become cold enough to cause condensation.

[003] The air cavity typically must be vented such that changes in environmental pressure due to changes in altitude do not cause the lenses to bulge or break. In typical double lens goggles, the vent opens into the volume between the goggles and the user's face. Unfortunately, the air between the lens and the wearer's face is typically very moist, primarily because of the wearer's perspiration. As a result, air passing from the space behind the lens into the cavity between the lenses is laden with moisture which can condense on the inner surface of the outer lens.

[004] A goggle could avoid introducing moisture laden air from behind the lens into the space between the lenses by venting the lens to the external environment through the outer lens. However, venting the inter-lens space through the outer lens tends to permit the entry of water through the vent into the space between the lens. Some goggles use a thin sheet of anhydrous material to cover a vent formed on the inner lens and thereby prevent the entry of water. However, the sheet is typically much larger than the vent and therefore occupies a substantial portion of the viewing area of the goggles. Furthermore, the thin anhydrous films are somewhat fragile and require complex housings such as are illustrated in U.S. Patent 4,290,673 to Yamamoto.

[005] In view of the foregoing it would be an advancement in the art to provide a compact, readily manufacturable vent for double lens goggles that reduces the possibility of fogging found in prior goggles.

SUMMARY OF THE INVENTION

[006] According to one aspect of the invention, a goggle includes first and second lenses that cooperate to define an air cavity therebetween. The first lens is positioned between the second lens and a user's face. A shroud extends outwardly from the lenses and cooperates with the first lens and a user's face to define a second air cavity. A vent is formed in the second lens such that air passing through the vent is drawn from the environment rather than the second air cavity. The vent is obstructed by a plug that is air permeable and liquid water impermeable.

[007] According to another aspect of the invention, the air permeable plug extends into the first air cavity and may abut the first lens. In a preferred embodiment, the plug is formed of sintered polyethylene, however other anhydrous or hydrophobic materials may be used. An expansion member may be inserted into the plug and urges the plug outwardly against the vent in order to retain the plug within the vent. The plug may have an aperture formed thereon sized to receive the plug. Alternatively, a permeable member having an aperture formed thereon is pinned to the vent by a resilient member. The resilient member includes a shaft insertable within the vent and having air channels formed therein. A cap may secure to the shaft and create a substantial seal such that air flowing into the vent by means of the air channels passes through the permeable member.

[008] The lenses may be assembled by forming a vent in one of the lenses and applying a semi-liquid adhesive along a perimeter of one of the lenses. The lenses are then brought together and the adhesive is cured. The plug or other liquid impermeable structure is then positioned to obstruct the vent.

BRIEF DESCRIPTION OF THE DRAWINGS

[009] Figure 1 is an isometric view of ski goggles in accordance with an embodiment of the present invention.

[010] Figure 2 is a cross-sectional view of a double lens assembly in accordance with an embodiment of the present invention. [Oil] Figures 3A and 3B are partial cross-sectional views of vents in accordance with embodiments of the present invention. [012] Figure 4 is a partial cross-sectional view of an alternative vent in accordance with an embodiment of the present invention. [013] Figure 5 is an isometric view of a rivet for mounting a permeable member to a vent in accordance with an embodiment of the present invention. [014] Figure 6 is an isometric view of a permeable member in accordance with an embodiment of the present invention. [015] Figure 7 is a cross-sectional view of a rivet and permeable member mounted to a vent in accordance with an embodiment of the present invention. [016] Figure 8 is a partial cross-sectional view of another alternative vent in accordance with an embodiment of the present invention. [017] Figure 9 is a partial cross-sectional view of another alternative vent in accordance with an embodiment of the present invention. [018] Figures 1OA and 1OB are cross-sectional views of goggle lenses illustrating a method for manufacturing a double lens assembly in accordance with an embodiment of the present invention. [019] Figures 1 IA-11C are partial cross-sectional views of a double lens assembly illustrating a method for inserting a permeable plug in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[020] Referring to Figure 1, goggles 10 include a frame 12 surrounding a lens 14.

A rim 16 or shroud 16, typically formed of a deformable material, extends around the frame 12. A vent 18 may be formed in the frame to permit air to enter the space between the lens 14 and a user's face. In some goggles 10 the vent 18 is selectively openable and closable by a user in order to adjust the temperature of the air captured between the goggles 10 and the user's face. A strap 20 secured to the frame is positioned around a user's head to maintain the goggles against a user's face.

[021] In the illustrated embodiment, the lens 14 is a double lens having inner and outer lenses. A vent 22 formed in either the inner or outer lens allows the pressure of the air cavity between the lenses to equalize with the environment. In the preferred embodiment, the vent 22 is formed in the outer lens such that air drawn into the air cavity comes from the environment and therefore has relatively low humidity, which is unlikely to cause fogging. The vent 22 is typically positioned to reduce interference with a user's field of vision. In one embodiment, the vent 22 is positioned at the center of the lens 14. In another, the vent 22 is positioned at the rear right or left edge of the lens.

[022] Referring to Figure 2, the lens 14 includes an inner lens 24a and an outer lens

24b. The lenses 24a, 24b tend to be curved to conform somewhat to a wearer's face. A seal 26 extends around the perimeter of the lenses 24a, 24b and cooperates with the lenses 24a, 24b to define an air cavity 28 substantially sealed from the environment, except for the vent 22. In a preferred embodiment, the seal 26 includes a silicone adhesive. In the illustrated embodiment, the outer lens 24b extends beyond the inner lens 24a and the seal 26 and the inner lens 24a is positioned within the perimeter defined by the seal 26. The outer lens 24b may include apertures, notches, or other features facilitating securement of the outer lens 24b to the frame 12.

[023] Referring to Figure 3A, in one embodiment, the vent 22 includes an aperture

30 formed in the outer lens 24b. A plug 32 is contained within the vent 22. The plug 32 may be formed of a resilient material such that an inner portion 34 of the plug 32 located within the air cavity 28 expands and aids in maintaining the plug 32 within the aperture 30. The plug 32 may also abut the inner lens 24a. The outer face 36 of the plug 32 may be flush with the outer surface of the outer lens 24b.

[024] The plug 32 is preferably formed of a material that is water impermeable and gas permeable. The material may include PTFE such as a GORE-TEX membrane. In the preferred embodiment, the material of the plug 32 includes sintered polyethylene such as POREX Corporation's hydrophobic IRM-0595. Plugs 32 including sintered polyethylene having a pore size of between about 5 and 25 microns may advantageously be used.

[025] Referring to Figure 3B, in one embodiment, the plug 32 includes an inner core 38 and a sheathe 40. The inner core 38 may be formed of a water impermeable and gas permeable material whereas the sheathe 40 is formed of an elastic material that is liquid impermeable and may also be gas permeable. Alternatively, the sheathe 40 is formed of a water impermeable and gas permeable material while the core 38 is formed of a liquid impermeable elastic material. Sintered polyethylene may have limited elasticity such that elastic core 38 or sheathe 40 may advantageously be used to bias the plug against the walls of the aperture 30 and/or to cause the inner portion 34 to expand within the air cavity 28. The base 42 of the plug may be angled, chamfered, scored, or contoured such that the core 38 is in fluid communication with the air cavity 28 even when the plug 32 is inserted such that it abuts the inner lens 24a. Alternatively, base 42 may be flat and the plug 32 may be inserted such that no substantial seal is created between the base 42 of the plug 32 and the inner lens 24a.

[026] Referring to Figure 4, in some embodiments, an expansion member 44 is used to secure the plug 32 within the aperture 30. The plug 32 may include an aperture 46 extending therethough to receive the expansion member 44. The expansion member 44 may include a shaft 48 sized to fit within the aperture 46 and a cap 50 secured to shaft 48. The shaft 48 may secure within the aperture 46 such that air is permitted to pass between the cap 50 and the outer lens 24b and contact the plug 32. The plug 32 may include a chamfered or tapered portion 52 to facilitate insertion into the aperture 30.

[027] Referring to Figures 5-7, in another embodiment, a rivet 54 retains a ring 56 over the vent 22. The rivet 54 includes a shaft 58 having one or more air channels 60 formed therein. The air channels 60 may be in the form of one or more grooves extending along the shaft 58. As shown in Figure 7, the ring 56 secures over the outer surface of one of the lenses 24a, 24b, preferably the outer lens 24b. A cap 62 secured to the shaft 58 may include a rim 64 extending around the upper edge of the ring 56 to retain the ring 56 and create a substantial seal between the rim 64 and the ring 56. Alternatively, the rim 64 may have a diameter smaller than the outer diameter of the ring 56 such that the rim 64 embeds itself within the ring 56 to create a substantial seal. The shaft 58 is preferably formed of a resilient material such that

it may be forced into the aperture 30 and thereafter exert a restoring force against the wall of the aperture 30 to retain the shaft 58. In some embodiments, the shaft 58 may include a pawl, tab, or like structure engaging the lens 24b to retain the shaft 58 within the aperture 30, such that engagement with the aperture 30 does not substantially retain the shaft 58 within the aperture 30. The shaft 58 may include a tapered or chamfered portion 66 to facilitate insertion of the shaft 58 into the aperture 30.

[028] Referring to Figure 8, in another embodiment, the vent 22 includes a patch

68 adhered to one of the lenses 24a, 24b, preferably the outer lens 24b. The patch 68 may advantageously be formed of sintered polyethylene, which is somewhat rigid and can be easily handled. However GORE-TEX or other anhydrous materials may also be used. The patch 68 may be secured to the lens 24a, 24b by means of adhesive extending around the aperture 30. The adhesive may be applied to the lens 24a, 24b or the patch 68 prior to attaching the patch 68 to the lens 24a, 24b.

[029] Referring to Figure 9, in another embodiment the vent 22 is embodied as one or more micro-holes 70. The holes 70 typically have a size such that liquid water does not readily pass through them. The holes 70 may be formed by laser drilling or like means. The holes 70 may have a diameter between 1 and 25 microns, preferably between 5 and 15 microns.

[030] Figures 1OA and 1OB illustrate one embodiment of a method for forming double lens goggles. The lenses 24a, 24b may be joined by first placing a bead 72 of a semi-liquid adhesive on one of the lenses 24a, 24b. The bead 72 is typically formed of a silicone adhesive. Referring to Figure 1OB, the other lens 24a, 24b is then brought into contact with the bead 72. In a preferred embodiment, the bead 72 is formed on the outer lens 24b. The bead 72 may define a perimeter that is approximately the size of the perimeter of the inner lens 24a. In a preferred embodiment the aperture 30 is formed in either of the lenses 24a, 24b, preferably the outer lens 24b, prior to contacting both lenses 24a, 24b to the bead 72 of adhesive. Forming the vent prior to joining the lenses is advantageous when using a semi- liquid adhesive inasmuch as gases are allowed to escape through the aperture 30 and are less likely to cause the bead 72 to shift due to changes in the relative pressure of the air cavity 28 caused by changes in temperature and environmental pressure while

the bead 72 of adhesive is being cured. Preferably after the bead 72 of adhesive is cured, the aperture 30 may be rendered substantially impervious to liquid entry using any of the structures described in Figures 1-9.

[031] Figures 1 IA-11C illustrate a method for inserting a plug 32, such as is illustrated in Figures 3A and 3B. A plug 32 according to the illustrated method may have a length 74 that equals or exceeds the distance 76 between the outer surface of the outer lens 24b and the inner surface of the inner lens 24a. The width 78 of the plug 32 also preferably exceeds the diameter 80 of the aperture 30. As shown in Figure HB, the plug 32 is inserted within the aperture 30 such that a portion 82 projects into the air cavity 28. The plug 32 may be inserted such that the plug 32 abuts the inner surface of the inner lens 24a. As shown in Figure HC, the portion 84 of the plug 32 projecting from the outer surface of the outer lens 24b has been trimmed such that the plug 32 is substantially flush with the outer lens 24b.

[032] From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.