Protective helmets are worn in many situations to protect the head from injury that can result from impact with a static or dynamic object. Such helmets are often worn by players of various sports. For example, baseball players typically wear helmets when they are batting to protect their head from the pitched baseball.
While current protective helmets offer protection to the wearer, improvements in protection are always welcome because of the potentially serious nature of head injuries.
The present disclosure may be better understood with reference to the following figures. Matching reference numerals designate corresponding parts throughout the figures, which are not necessarily drawn to scale.
Disclosed herein are protective helmets that offer improved protection to the wearer. As described below, the helmets include faceted outer surfaces that reduce the potential for normal impacts and therefore dissipate energy that might otherwise be transmitted to the wearer's head.
In the following disclosure, various specific embodiments are described. It is to be understood that those embodiments are example implementations of the disclosed inventions and that alternative embodiments are possible. All such embodiments are intended to fall within the scope of this disclosure.
The outer shell 12 is generally rigid and can be made of any material that provides impact protection to the wearer. In some embodiments, the shell 12 is made of a polymeric material that is approximately 1 to 4 mm thick. The polymeric material that is used can depend upon the application of the helmet and the level of protection that is required. In some embodiments, the shell 12 is made of a long fiber thermoplastic (LFT) material. The use of LFTs is desirable because they provide high levels of protection like continuous fiber reinforced composites but can be processed using traditional plastics molding equipment. Therefore, parts can be manufactured at medium- to high-volume rates with excellent consistency and repeatability. Long fibers (e.g., fiber lengths of about 3 mm to 50 mm) provide an elastic modulus and a tensile strength that is up to approximately 80% of that obtained using continuous fibers.
In some embodiments, LFT materials are formed by hot melt-impregnating continuous reinforcing fiber into a thermoplastic resin. The mixture can be cooled and formed (e.g., chopped) into discontinuous reinforcing fiber pellets. The amount of thermoplastic resin can be approximately 50 to 99 weight % of the LFT material and the amount of continuous reinforcing fiber (and once cut into the discontinuous reinforcing fiber) can be approximately 0.1 to 50 weight % of the LFT material. Example thermoplastic resins include polyamide, acrylonitrile butadiene styrene (ABS), polyphenylene sulfide, polypropylene, poly ether ether ketone, poly ether ketone, polyethylene, poly butylene terephthalate, poly ethylene terephthalate, polyoxymethylene, and combinations (mixtures) thereof. Example reinforcing fibers include carbon, glass, aramid, polypropylene, polyethylene, basalt, poly{diimidazo pyridinylene (dihydroxy) phenylene}, natural fibers such as flax, kenaf, bamboo, jute, sisal, and combinations (mixtures) thereof.
In other embodiments, the outer shell 12 is made of a non-reinforced polymer material. Examples of such materials include polyamide, ABS, polyphenylene sulfide, polypropylene, poly ether ether ketone, poly ether ketone, polyethylene, poly butylene terephthalate, poly ethylene terephthalate, polyoxymethylene, or combinations (mixtures) thereof.
In still other embodiments, the outer shell 12 is made of a syntactic material that comprises a plurality of microspheres (also referred to as cenospheres or microballoons) that are compounded with a thermoplastic resin. Such a material is schematically depicted in
The resin 94 can comprise a polymeric resin. In some embodiments, the resin is a thermoplastic resin comprising an olefin, such as polypropylene, polyethylene, or combinations (mixtures) thereof. Alternatively, the thermoplastic resin can comprise an engineered polymer, such as polyamide, polyether ether ketone (PEEK), polyether ketone (PEK), polyethyleneimine (PEI), polyphenylene sulfide (PPS), or combinations (mixtures) thereof.
The protective helmet 10 can be used in substantially any context. In some embodiments, the helmet 10 is used to protect the wearer's head during sports activities. In the specific example illustrated in
Irrespective of its particular application, the outer surface 18 of the shell 12 comprises a plurality of facets 20 that lie in non-parallel planes. In some embodiments, the facets 20 are generally planar (i.e., not curved) and reduce the likelihood that a projectile will impact the shell 12 from a normal (perpendicular) direction. Accordingly, such projectiles will have the tendency to skirt or skip across the surface 18 of the shell 12. In some embodiments, each facet 20 defines a similar geometric shape. In some embodiments, each facet 20 is triangular and therefore includes three linear sides. In such cases, the triangles can have three equal angles (equilateral triangle), two equal angles (isosceles triangle), or no equal angles (scalene triangle). In some embodiments, the groups of facets 20 define multifaceted prisms on the surface 18 of the shell 12, such as the hexagonal, six-facet prism 22 highlighted in
In some embodiments, each facet 20 has a nominal dimension of approximately 1 to 3 inches. In the example embodiment of
As shown in
With reference to
With further reference to
In each of the above-described embodiments, the inner surface of the outer shell 12 can either be faceted in a similar manner to the outer surface 18 or can be smooth similar to conventional helmets. Regardless, it is reiterated that a relatively soft inner liner comprising one or more flexible and/or resilient pads can be provided within the shell to cushion the wearer's head and/or dissipate direct or rotational force.
This application claims priority to co-pending U.S. Provisional Application Ser. No. 61/843,599, filed Jul. 8, 2013, which is hereby incorporated by reference herein in its entirety.
This invention was made with Government support under grant or contract number W911NF-04-2-0018 awarded by the Army Research Laboratory. The Government has certain rights in the invention.
Filing Document | Filing Date | Country | Kind |
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PCT/US14/43351 | 6/20/2014 | WO | 00 |
Number | Date | Country | |
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61843599 | Jul 2013 | US |