The present disclosure relates to a retention system for a helmet and, in particular, a system for securing straps to a helmet to retain the helmet on the wearer.
Helmets, such as ballistic helmets, commonly include retention systems, which may include retention straps or harnesses, for securing the helmet onto a wearer's head. The retention straps may be affixed to the helmet with screws or grommets that pass through holes machined or otherwise formed into the helmet. As a number of helmets are formed of composites, including ballistic composites, it may be very difficult to machine a hole through the helmet to secure the hardware that affixes the retention straps to the helmet. The holes may also form stress concentrations, regardless of the material the helmet is formed of, reducing the overall ballistic protection of the helmet. Further, hardware, such as grommets or screws, may cause additional damage to the wearer when the helmet is hit by a projectile or other object.
An aspect of the present disclosure relates to a helmet. The helmet includes a helmet shell including an edge and an edge trim receiving the edge of the helmet shell. The helmet also includes a retention system including at least two points where the retention system is secured to the helmet and a releasable mechanical fastening system, wherein the mechanical fastening system includes a first mating portion and a second mating portion, which releasably mates with the first mating portion. The first mating portion is affixed to the points and the second mating portion is affixed to one of the helmet shell or the first mating portion. The first and second mating portions include hook and loop fasteners. In addition, an attachment hook is provided for each point of the retention system extending from the edge trim through which each of the points pass through.
Another aspect of the present disclosure relates to a system for providing a helmet. The system includes a retention system including at least two mating straps, wherein each strap includes a first mating portion. The system also includes a helmet shell including an edge, an edge trim receiving the edge, at least two attachment hooks extending inwardly from the edge trim, and a second mating portion releasably affixed to the first mating portion. The first mating portion passes through one of the attachment hooks and the attachment hook prevents the first mating portion affixed to the second portion from being pulled at an angle of greater than 45 degrees from the helmet shell wall.
A further aspect of the present disclosure relates to a method of securing a retention system of a helmet. The method may include passing a first mating portion provided on a point of a retention system through an attachment hook provided on a helmet and mating the first mating portion to a second mating portion affixed to the helmet and securing the retention system to the helmet.
The above-mentioned and other features of this disclosure, and the manner of attaining them, may become more apparent and better understood by reference to the following description of embodiments described herein taken in conjunction with the accompanying drawings, wherein:
a illustrates an embodiment of a retention system including hook fastener strips for securing the retention system to the helmet.
b illustrates an embodiment of a helmet including loop fastener strips for securing the retention system of
a illustrates another embodiment of a retention system including loop fastener strips for securing the retention system to the helmet.
b illustrates another embodiment of a helmet including hook fastener strips for use with the retention system of
a illustrates close up view 4a of
b illustrates cross-section 4b of
a illustrates an embodiment of an attachment hook with a closed configuration.
b illustrates an embodiment of an attachment hook with an open configuration.
The present disclosure relates to a retention system for a helmet and, in particular, a fastener system for securing a retention system to a helmet to retain the helmet on the wearer. The retention system includes a harness or series of straps that secure a helmet to a user's head. The fastener system may affix the retention system to the helmet in a relatively quick and secure manner without modification to the shell of the helmet.
a, 1b, 2a and 2b illustrate an embodiment of a helmet 10 and fastener systems for affixing the retention system 12 to the surface of the helmet. The helmet includes a shell 14 formed of a single material or multiple materials, such as composites. In some embodiments, the shell 14 is formed from one or more thermoplastics, thermosets, ceramics, metals or metal alloys, and combinations thereof. For example, the shell 14 may be formed from multiple layers of woven or nonwoven fabrics bonded together utilizing a thermoplastic or thermoset adhesive. In some embodiments, the fabrics are formed, for example, from polyester, nylon, polyethylene or polypropylene fibers. In addition, the fibers may be highly oriented fibers. Examples of fibers that are used in the fabrics include fibers such as TWARON (available from Teijin), ZYLON (available from Toyobo Corporation), SPECTRA (available from Honeywell Corporation), DYNEEMA (available from DSM), etc. The fabrics may also be impregnated with various resins, such as vinyl ester resins, polyester resins, epoxy resins, etc. The shell 14 is formed into one of a number of geometries, including for example, low-cut or high-cut combat helmet geometries.
A suspension system 16 is, optionally, provided within the helmet, including one or more liners or pads that may be used to prevent the shell 14 from directly contacting the head or to absorb some of the force exerted by a helmet on a wearer's head when the helmet is hit by an object. The suspension system 16 includes a compliant material such as foam formed from silicone or urethane materials. The compliant material is, optionally, covered in a textile such as woven fabric, nonwoven fabric, leather, or other materials and may be positioned within the helmet shell 14 either in a fixed or adjustable manner. For example, if fixed, the suspension system may be adhered to the shell using a chemical bonding process such as pressure sensitive adhesive, solvent activated adhesive or heat activated adhesive system. Non-limiting examples of adhesive compositions include acrylic, synthetic rubber, polyvinyl acetate, polyvinyl alcohol, acrylates, polyethylene, nylons, cyanoacrylates, epoxies, silicone, phenolics polyurethanes, copolymers thereof, etc. In other embodiments, a fixed suspension system may be ultrasonically or dielectrically welded to the shell. If positioned within the shell in an adjustable manner, the pads or liner may be affixed using mechanical fasteners such as hook and loop fasteners or slid into pockets formed in the helmet. The suspension pads have a thickness in the range of 1 mm to 100 mm, including all values and ranges therein. In addition, varying thicknesses may be used for individual suspension pads provided in a single helmet.
As illustrated in
The retention system 12 includes a mechanical attachment 20 for opening and closing the chin strap 18. The mechanical attachment may be positioned near the wearer's chin, so that the retention system and helmet may be released and passed over and/or behind the wearer's head. The mechanical attachment includes, for example, a buckle such as a side release buckle or front release buckle, which may be made of thermoplastic, thermosets, metals or metal alloys. Furthermore, the retention system 12 optionally includes a chin pad 22 attached to the chin strap 18. The chin pad may or may not include compressible materials, such as foam or felt.
As noted above, the neck strap 24 passes behind the nape of the neck of the wearer. This may aid in reducing rotational movement of the helmet in the anterior-posterior direction and/or lateral direction. While not illustrated, a mechanical attachment may optionally be provided for opening or closing the neck strap 24. Furthermore, a neck pad 26 may be provided that rests against the nape of the neck, which is integrated into the retention system. The neck pad 26 may be removable or permanently affixed. The neck pad may or may not include compressible material, such as foam or felt.
The points of the harness 28a, 28b, 28c, 28d (hereinafter 28) include length straps 30a, 30b, 30c, 30d (hereinafter 30) that may be adjusted to lengthen or shorten the retention device. Tension locks are optionally provided for adjusting the length of each strap to aid in adjusting the straps and maintaining the adjustment. The various straps (chin, neck, length) may be formed from webbing, such as nylon webbing, or webbing made from other materials, including natural fibers such as cotton, thermoplastic materials including olefins such as polypropylene, acrylic, para-aramids (KEVLAR), ultrahigh molecular weight polyethylene (DYNEEMA), polyester, etc. Other materials, such as leather, may be utilized as well.
The retention system 12 is affixed to the helmet 10 utilizing a mechanical fastener system and attachment hooks. The mechanical fastener system includes a first mating portion and a second mating portion, which may be release-ably affixed or mated together. Preferably, the fastener system includes hook and loop fasteners and decouples under peel or shear forces.
In one embodiment, as illustrated in
In one non-limiting embodiment, the strips on the retention system are 0.25 inches to 1.5 inches in width and in the range of 1 inch to 4 inches in length, including all values and increments therein, such as 0.75 inches in width by 2.0 inches in length, etc. Likewise, in such an embodiment, the strips on the helmet 10 are 0.25 inches to 1.5 inches in width and in the range of 1 inch to 6 inches in length, including all values and increments therein, such as 0.75 inches in width by 4.0 inches in length.
The first mating portion of the fastener 40, 42 (see
The second mating portion of the fastener 44, 48 (see
The second mating portions are affixed to the shell using chemical methods, mechanical methods, thermal methods or combinations thereof. In some embodiments, the second mating portions are affixed to the helmet by thermal point bonding or ultrasonic or dielectric welding to the shell, depending on the composition of the shell.
In other embodiments, the second mating portions are adhered to the shell using a pressure sensitive, solvent activated or heat activated adhesive system disposed between the second mating portion and the shell. Non-limiting examples of adhesives include acrylic, synthetic rubber, polyvinyl acetate, polyvinyl alcohol, acrylates, polyethylene, nylons, cyanoacrylates, epoxies, silicone, phenolics, polyurethanes, copolymers thereof, etc. An example of an adhesive includes a modified acrylic adhesive available from 3M under product number 9482PC PSA. Surface treatment prior to application of an adhesive includes solvent or chemical cleaning, active surface treatments (corona, flame plasma treatment), metallic, plastic, composite, elastomeric adherents, primers or promoters.
Further, in some embodiments, the adhesive may exhibit a peel strength as measured by ASTM-D-3330 (modified) 90° peel at 12 inches per minute, 22° C. and 50% relative humidity, of 70 oz./in. or greater, such as 70 oz./in. to 110 oz./in. including all values and increments therein, when tested relative to polypropylene surfaces. Greater peel strength may be exhibited when surfaces exhibiting higher surface energies are utilized and may be up to 230 oz./in.
A strip of hooks may include in the range of 400 to 2,000 hooks per square inch, including all values and ranges therein, such as 400 to 1,000 hooks per square inch or 1200 to 1500 hooks per square inch or 1400 hooks per square inch. Further, the hook height may be in the range of 0.01 to 0.05 inches, including all values and ranges therein, such as 0.02 to 0.04 inches. An example of hooks including hooks available from VELCRO under the product number HTH 792.
In some embodiments, the hook fasteners may be unidirectional hook fasteners. As illustrated in
The loops may be formed from a tufted woven or nonwoven textile, or a textile including a plurality of loops fixed thereon. For example, the loops may include knit loops. Examples of loops include Loop 1000 or Loop 3610, available from VELCRO.
In some embodiments, the thickness of the mated hook and loop fasteners is less than the thickness of the suspension system pieces provided within the shell. That is, the suspension system may exhibit a first thickness T1 and the mated mechanical fasting system, or first and second mating portions, may exhibit a second thickness T2, which is less than the first thickness T1. Therefore, the wearer may not detect the presence of the fastener system within the helmet. The height of the hook and loop fastener, when mated, may be in the range of 0.03 to 0.5 inches, including all values and ranges therein.
In addition, the hook and loop fasteners may exhibit a dynamic tensile disengagement strength, when tested at 12 inches per minute at 22° C. at 50% relative humidity of 2.8 to 7.1 pounds force per square inch. The hook and loop fasteners may also exhibit a dynamic sheer strength of 40 to 42.4 pounds force per square inch, including all values and increments therein, when tested at a 1 inch by 1 inch overlap and at 12 inches per minute at 22° C. at 50% relative humidity of 2.8 to 7.1 pounds force per square inch.
As noted above, the retention system 12 may be affixed to the helmet 10 utilizing a mechanical fastener system, including hook and loop fasteners which are threaded through an attachment hook affixed to the helmet or helmet edge trim.
As illustrated, the attachment hook 32 is of an oblong, rectangular or “D” configuration loop and exhibit a closed geometry or open geometry as illustrated in
The edge trim is formed of a polymer material, such as a thermoplastic polymer, including polycarbonate, acrylonitrile butadiene styrene, poly(vinyl chloride), polyamide, etc. For example, the edge trim piece may be molded by applying heat and/or pressure to a polymer material to reduce the material viscosity and causing the material to flow into a form or mold, such as through injection or compression molding. The polymer material may flow around the attachment hook and the attachment hook may be mechanically retained by the edge trim piece upon cooling and/or solidifying of the polymer material.
The edge trim piece 70 is then be affixed or otherwise adhered to the helmet 10′. In some embodiments, a chemical adhesive may be used to adhere the edge trim piece to the helmet. In other embodiments, welding, such as ultrasonic welding, may be used to affix the edge trim piece to the helmet. In additional embodiments, the edge trim piece 70 is over-molded onto the periphery of the helmet.
In further embodiments, the attachment hook 32 is molded integrally as part of the edge trim 70, as illustrated in
Threading the first mating portion through the attachment hooks 32 restrains the forces that may be enacted upon the mechanical fastener system, as illustrated in the cross-section of
The attachment hook 32 constrains the forces pulling the length strap 30 away from the helmet wall 46, at angle β and generally reduces the forces pulling against the mechanical fastener 42, 48, to those parallel to the interior wall of the helmet F2. As the hook and loop fastener exhibits a greater shear strength than peel strength, the retention system is less likely to decouple from the helmet 10′ during normal use, i.e., when worn. The peel strength may be understood as the strength of the mechanical fastener against a force applied in a direction generally planar to the surfaces of the hook and loop fastener, which surface may be generally parallel to plane A-A. The peel strength may be understood as the strength of the mechanical fastener against a force applied in a direction at an angle, such as angle β, and away from the generally planar surfaces of the hook and loop fastener. Thus, the attachment hook 32 may prevent delaminating of the first and second portions of the hook and loop fastener.
It may be appreciated that in the above embodiment, when a force is applied against the straps in the retention system, the edge trim does not bear the entire force. Rather, most of the force is applied to the helmet and due to the presence of the attachment hooks the force is applied more as a shear force than a peel force.
In a further embodiment, when utilized with the attachment hooks 32, the fastener system may again include a first mating portion and second mating portion, which may be release-ably affixed together. Referring to the illustration in
Similar to
At the end of the first and second mating portions 76, 78, a grip is optionally provided to facilitate detachment of the retention system. The grip 82 is located at the distal end 84 of the hook and loop strips 76, 78 and includes a portion of the strap where the hooks or loops are not present. In further embodiments, the grip 82 may include a ring or loop.
It may therefore be appreciated that the retention system is affixed to the helmet using a fastener system that does not require machining through the thickness of the helmet. It is contemplated that without such machining, the mechanical integrity of the helmet may be improved. Furthermore, passages through the helmet shell are not necessary and, therefore, may not be present. It may also be appreciated that in some embodiments the helmet shell includes no metal fasteners in the retention system or in the mechanical fastening system for affixing the retention system to the helmet. Further, it may be appreciated that the injury due to mechanical fasteners such as grommets, snaps or screws may be reduced.
The hook and loop systems herein may be utilized for a variety of helmet types. For example, it is employed in tactical helmets including advanced combat helmets or riot helmets; industrial helmets including firefighting helmets, hardhats or welding helmets; sports helmets including bicycle helmets, motorcycle helmets or climbing helmets; and other applications. In utilizing hook and loop fasteners to secure the retention system to the helmet, the retention system may be easily removed if damaged. Or, if the wearer prefers a given retention system it may be readily moved from helmet to helmet.
The helmet, including the retention system, exhibits a total weight of less than 4 pounds, including all values and ranges from 2.8 pounds to 3.3 pounds, such as 3.2 pounds. The retention systems herein exhibit a pull strength of greater than 150 lbf and less then 300 lbf, such as in the range of 190 lbf to 220 lbf, including all values and ranges therein. In addition, the maximum extension at pull strength is less than 3.00 inches, including all values and ranges therein, such as 0.1 inch to 3.00 inches, 2.0 inches to 3.00 inches, 2.00 inches to 2.75 inches, etc. The pull strength of the retention systems exceed the 150 lbf minimum set under the Purchase Description for the Enhanced Combat Helmet, GL/PD 09-04 H, May 3, 2012.
The present disclosure is also directed to a method for securing a retention system of a helmet with mating portions of hook and loop fasteners. The method may include mating a first mating portion affixed to a retention system and a second mating portion affixed to a surface of a helmet by passing the first mating portion through an attachment hook provided in the helmet, securing the retention system to the helmet. The method may also include chemically securing the second mating portion onto the helmet surface. The method may also include mechanically securing the first mating portion to the retention system.
In this example, the maximum pull strength applied to the retention system before failure of the system was measured. Four ballistic helmets were manufactured according to the example set forth in
The foregoing description of methods and embodiments has been presented for purposes of illustration. It is not intended to be exhaustive or to limit the claims to the precise steps and/or forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be defined by the claims appended hereto.
The present application claims the benefit of the filing date of U.S. Provisional Application No. 61/540,260, filed on Sep. 28, 2011, the disclosure of which is incorporated herein by reference.
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Entry |
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GL-PD-09-04H Purchase Description (PD) for the Enhanced Combat Helmet, May 3, 2012, 79 pages. |
Number | Date | Country | |
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61540260 | Sep 2011 | US |