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  Helmet face shieldUSPTO Application #: 20060010572Title: Helmet face shield Abstract: A face shield for headgear comprises a generally transparent main lens, adapted for engagement to the headgear. The main lens comprises a curved inner and outer main lens surfaces and has a central recessed portion with a curved recessed inner lens surface and a curved recessed outer lens surface. The recessed inner lens surface and the recessed outer lens surface are respectively offset from the curved inner and outer main lens surfaces. The recessed portion is adapted to receive a secondary lens such that a sealed air gap is formed between the secondary lens and the main lens, thereby forming a sealed double pane lens having condensation reduction properties. (end of abstract) Agent: Ogilvy Renault LLP - Montreal, QC, CA Inventor: Thomas D. A. Douglas USPTO Applicaton #: 20060010572 - Class: 002231000 (USPTO) Related Patent Categories: Apparel, Head Coverings, Skirts, Trousers Or Overalls, Stays Or Protectors The Patent Description & Claims data below is from USPTO Patent Application 20060010572. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 10/769,979, filed on Feb. 3, 2004, and which claims priority on US Provisional Patent Application No. 60/444,159, filed on Feb. 3, 2003. The entire contents of both of which are incorporated herein by reference. TECHNICAL FIELD [0002] The present invention relates generally to shields for protective helmets used for snowmobiling, motorcycle riding and the like. More particularly, the present invention relates to a protective face shield having a removable lens portion. BACKGROUND OF THE INVENTION [0003] Protective helmets such as, for example, those used for snowmobiling and motorcycle riding, are well known. They typically include a generally transparent face shield or lens. Two distinct types of helmet face shields are typically employed. Shields having a single pane lens are generally used in warmer environmental conditions. Face shields having a dual lens construction comprising an inner lens and an outer lens, are most often used in colder and more humid conditions. In cold weather, single pane lenses tend to fog up, consequently impairing the rider's vision. However, single pane lenses generally provide better visual properties in comparison with double pane lenses, the thinner single lens causing less optical distortion. Nonetheless, double pane lenses are almost universally used in colder climatic conditions, in order to help keep the face shield substantially free of condensation. [0004] Many kinds of face shields employ additional techniques to further attempt to prevent fogging. These include lenses having an electrical heating system, wherein an inner lens surface is coated with an electrically conductive film and two electrodes, on opposite edges of the lens, permit an electrical current to flow across the film covering the lens, thereby inhibiting condensation build up thereon. Other anti-condensation methods are also well known, such as those providing directed ventilation along an inner surface of the lens or employing a hydrophilic anti-condensation layer, in the form of a sheet, film or other covering, that is fitted within an outer lens. These additional anti-condensation devices are typically used in combination with a double-paned lens. [0005] Most face shields having such a double pane construction comprise two lenses that are contained within a separately constructed perimeter frame, which provides support for the double-paned lens and permits pivotable attachment thereof to the helmet. Double pane lens assemblies are significantly thicker than single paned lenses, and their attachment to some helmets which are not specifically designed to accommodate them can accordingly be difficult without the rather bulky perimeter frame. These face shield perimeter frames can significantly add to the manufacturing cost of the face shield assembly, unduly add bulk and weight to the helmet, and contribute to aerodynamic inefficiencies and increased wind noise. [0006] Most known face shields that do not comprise perimeter frames, and have double pane lenses or have a hydrophilic layer superimposed on a single lens, do not permit removal of one of the lens panes or the anti-condensation layer. However, it has been known to provide such a frame-free face shield for a protective helmet having a detachably engaged inner lens. U.S. Pat. No. 5,765,235 issued Jun. 16, 1998 to Derek Leslie Arnold, for example, discloses an anti-condensation visor comprising an outer visor for attachment to a helmet and an inner visor, made of hydrophilic material, detachably fitted against the inside wall of the outer visor and held there against by at least one mechanical retaining element. The inner visor must rest against the inside wall of the outer visor in such a way that no space is left between them. U.S. Pat. No. 4,584,721 issued Apr. 29, 1986 to Tamenobu Yamamoto, discloses a helmet face shield having an electric heating device for preventing fogging. The device comprises a removable inner lens piece attached behind the outer helmet lens. The inner lens piece is generally engaged to the outer lens by a mechanical engagement element such as a snap fastener. SUMMARY OF THE INVENTION [0007] It is an object of the present invention to provide an improved face shield for a protective helmet. [0008] It is another object of the present invention to provide a face shield having a frameless main lens capable of receiving a second lens portion that can be sealed to the main lens with an air gap therebetween to create a double pane lens. [0009] The present invention permits an inner lens to be engaged to an outer lens such that it is offset therefrom but sealed thereto. The present invention further permits the single pane lens to be converted into a double pane lens having improved anti-condensation properties provided by an air gap trapped between the inner and outer lenses of the sealed double pane lens. [0010] Therefore, in accordance with the present invention, there is provided a face shield for headgear comprising: a generally transparent main lens adapted for engagement to the headgear; the main lens comprising curved inner and outer main lens surfaces and having a central recessed portion, the recessed portion having a recessed curved inner lens surface and a recessed curved outer lens surface, the recessed inner lens surface and the recessed outer lens surface being respectively offset from the curved inner and outer main lens surfaces; and the recessed portion being adapted to receive a secondary lens therein such that a sealed air gap is formed between the secondary lens and the main lens, thereby forming a sealed double pane lens having anti-condensation properties. [0011] There is also provided, in accordance with the present invention, a face shield for headgear comprising: a generally transparent main lens adapted for engagement to the headgear; the main lens comprising curved inner and outer main lens surfaces and having a central recessed portion, the recessed portion having a recessed curved inner lens surface and a recessed curved outer lens surface, the recessed inner lens surface and the recessed outer lens surface being respectively offset from the curved inner and outer main lens surfaces; and a secondary lens, selectively engageable within the recessed portion of the main lens such that a sealed air gap is formed between the secondary lens and the main lens, thereby selectively forming a sealed double pane lens having anti-condensation properties. BRIEF DESCRIPTION OF THE DRAWINGS [0012] Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which: [0013] FIG. 1 is a perspective view of a face shield according to the present invention engaged to a protective helmet; [0014] FIG. 2 is an exploded perspective view of the helmet face shield of FIG. 1, showing a main lens and a secondary lens; [0015] FIG. 3 is a front elevation view of the helmet face shield of FIG. 1; [0016] FIG. 4 is a horizontal cross-sectional view taken along line 4-4 of FIG. 3; and [0017] FIG. 5 is a perspective view of an alternate embodiment of the secondary lens for engagement with the main lens of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0018] Referring to FIG. 1, the face shield 10 is adapted to be engaged to, and used with, headgear such as a protective helmet 13 as conventionally used for motorcycle riding, snowmobiling, flying and the like. The face shield 10 is also adapted for use with other protective headgear comprising a transparent face shield, such as paintball masks for example. The face shield 10 comprises primarily a generally transparent main lens 12, thereby providing a single pane lens that does not require a perimeter frame for support or engagement to the protective helmet 13. The main lens 12 is preferably a moulded plastic one-piece element, having a thickness of approximately 2 mm (about 0.07874 inches). The main lens 12 is preferably injection moulded, however other manufacturing techniques could also be used, such as drape or vacuum moulding for example. One skilled in the art will also appreciate that the main lens 12 can have a non-uniform thickness throughout. Particularly, as is known in the art, the lens can be formed such that it is thickest at a center point thereof and becomes gradually thinner towards each edge of the lens. This causes the least distortion of light passing through the lens, enabling the single paned main lens 12 to provide substantially distortion free optical characteristics. The main lens 12 is preferably formed having a curvature about a substantially vertical axis that substantially corresponds to that of the protective helmet 13 to which it is to be engaged, however it generally comprises a substantially semi-circular shape. The main lens 12 can also be outwardly convex throughout the semi-circular length thereof, having a second curvature about a substantially horizontal axis, creating a complex lens curvature. The curved main lens 12 comprises a curved inner main lens surface 14 and a curved outer main lens surface 16. Continue reading... Full patent description for Helmet face shield Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Helmet face shield patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Helmet face shield or other areas of interest. ### Previous Patent Application: Maternity garment with double waistband design Next Patent Application: Charm display device and the like Industry Class: Apparel ### FreshPatents.com Support Thank you for viewing the Helmet face shield patent info. 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