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The present application claims priority to, and the benefits of, U.S. Ser. No. 60/662,063, filed Mar. 15, 2005, the entire disclosure of which is hereby incorporated by reference.
This invention relates to safety helmets, in particular a headband for adjusting and securing the helmet to a wearer's head.
Helmets for head protection are worn in a variety of environments and for various purposes. Protective helmets generally have a spherically shaped rigid outer shell which covers the head and is secured to the user's head by means of a flexible chin strap. Various approaches have been used to adapt helmets to fit the variety of head shapes and sizes of different users. One such approach is to suspend a flexible headband within the interior of the helmet and provide a way to adjust the girth of the band to fit the user's head. While this approach adapts easily to different head shapes and sizes, it cannot absorb impact energy and therefore provides little protection against trauma, especially from the side of the helmet. Because of the importance of protecting the head against blunt trauma, recent refinements in helmets have replaced the headband with pads or a liner made of a compressible material, such as foam, situated between the user's head and the helmet shell. In these designs, however, it is difficult to provide both a comfortable and secure fit because low-density material, which has benefits with respect to comfort, allows the helmet to move too easily and provides less impact protection. Higher-density materials can absorb impact energy but do not adapt well to different head sizes and shapes. There remains a need, therefore, to fit a helmet to the user's head in a manner that is adjustable, comfortable, secure, stable, yet which provides protection against trauma.
The present invention improves on conventional approaches to fitting a safety helmet by providing a flexible headband that can be adjusted to fit the shape and size of the wearer's head and which also provides stand-off from the inner surface of the helmet shell. The stand-off provides space within which impact-absorbing materials may be situated in order to absorb blunt impact energy.
The headband generally comprises a flexible (e.g., plastic) band that may be fabricated as a thin, flat component which is curved into a circular shape by, for example, joining its ends together. In a preferred embodiment, the band is fabricated by injection molding to create and control the features described below, but alternative fabrication techniques as are well known in the art can also be used. The ends of the band are desirably joined at the back of the wearer's head in a manner that allows adjustment of the circumference of the headband. This may be accomplished, for example, by providing one or more tabs molded on one end which snap into any of two or more spaced slots in the other end, thereby providing multiple positions for joining the ends, each of which corresponds to a smaller or larger circumference for the headband. Other well-known means for adjusting the circumference of the headband, such as frictional engagement, hook-and-loop fasteners, clasps, etc., may also be used.
The headband further comprises a plurality of connecting arms to facilitate joining the headband to the helmet shell at multiple positions. For example, in embodiments with four connecting arms, two are positioned on each side, one is in front and the other is in back. In a preferred embodiment the connecting arms are molded with thin bands oriented to provide bending lines, sometimes referred to as “living hinges.” These bending lines allow the arms to flex horizontally and vertically. Each connecting arm has an aperture for engaging a fastener to join the headband to the helmet shell. The connecting arm may, for example, be joined to the helmet using an anchor having an off-round (e.g., square or angular) post that allows the connecting arm to resist rotation. The connecting arm so connected is constrained to flex in a direction approximately perpendicular to the surface of the helmet shell. When at least two of the connecting points are oriented so that the directions of flexure intersect at a point inside the diameter of the circular headband, the headband resists displacement toward the helmet shell.
As noted above, impact liner materials may be to be placed in the top of the helmet and optionally in the space between the headband and the helmet shell. Softer “comfort” pads may be positioned between the impact liner and the wearer's head to provide a cushioned surface in contact with the wearer's head. The positional security provided by the improved headband of the present invention means that the impact liner and comfort pads need not play a significant role in the fit or retention of the helmet. This allows greater choice of materials and shapes than is the case with helmets that rely on the energy absorbing materials to also provide positional security.
Accordingly, in a first aspect, the invention comprises an interior head-retention element for use in connection with a safety helmet. The retention element comprises an adjustable-size headband for engaging a wearer's head, and a plurality of stand-off attachment elements, disposed about the headband, for facilitating spaced-apart attachment of the headband to the helmet. The stand-off elements yieldably resist movement of the helmet toward the wearer's head. The resistance is yieldable in the sense that impact energy is at least partially absorbed rather than transmitting the energy, through excessive resistance, to the wearer.
In preferred embodiments, the stand-off attachment elements each comprise a generally U-shaped member. For example, as described above, each U-shaped member may be folded over a plurality of bending lines that accommodate at least horizontal, and desirably some vertical flexure. The stand-off attachment elements desirably have directions of horizontal flexure that intersect within the headband.
In another aspect, the invention comprises a helmet incorporating the head-retention element described above.
In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the following drawings, in which:
FIG. 1 is a front elevational view of a user with safety helmet in place;
FIG. 2 is a cross-section of the safety helmet shown in FIG. 1, taken along the line 2-2;
FIG. 3 is a cross-section of the safety helmet shown in FIG. 1, taken along the line 3-3;
FIG. 4 is a perspective view of the headband of the present invention removed from the helmet; and
FIG. 5 is an exploded view of a portion of the headband and other components of a helmet retention system.
With reference to FIGS. 1 and 2, a helmet 10 is shown secured to the wearer's head by a pair of flexible straps 13a, 13b secured to the helmet 10 by respective screws 15a, 15b. The flexible straps 13a, 13b at the front of the helmet join with straps 13c, 13d from the back of the helmet and are secured at the chin by means of a flexible strap 16, which scoops beneath and may cup the chin. A detachable buckle comprising a male component 19a and a female component 19b may be used to secure the straps. When the buckle is detached, separating the components 19a, 19b, the chin strap 13 is released, allowing the wearer to remove the helmet 10.
With reference to FIG. 2, which shows the helmet from the right side of the wearer (including an outline of the wearer's head for reference), the left half of the headband 22 of the present invention is shown secured at the front left side of the helmet 10 by a screw 15b, and at the back left side by another screw 15c. An impact-absorbing liner 28 may be positioned between the wearer's head and the helmet shell 10. The impact liner can be formed from conventional materials such as expanded polypropylene (EPP), expanded polyethylene (EPE), expanded polystyrene (EPS), or visco-elastic foam. Other impact-absorbing structures taught in U.S. Pat. Nos. 6,777,062 and 6,032,300 may also be used to advantage.
Softer pads (representatively shown at 31a, 31b, 31c) may be positioned between the wearer's head and the impact material 28 to provide a cushioned surface in contact with the wearer's head. By way of example, such comfort pads may be made from urethane foam or EVA foam.
FIG. 3 shows the headband 22 of present invention attached to the helmet shell 10 by a pair of screws 15a, 15b in front and another pair of screws 15c, 15d in back. The impact liner 28 and the comfort pads 31a-31e are positioned at the top of the helmet.
FIG. 4 shows the headband 22 removed from the helmet. The headband is preferably fabricated from a flexible plastic such as nylon or polypropylene and molded as a flat band that may be curved into a circular shape with the narrowed end 34a passing through a slot 35 in the other end 34b to join the two ends of the headband at the back of the wearer's head. Headband end 34a is molded with tabs (not shown) sized and spaced appropriately to match a series of slots 36 formed in headband end 34b. Providing more slots 36 than tabs in the headband allows the wearer to select from multiple positions for joining the ends 34a, 34b, each position corresponding to a smaller or larger circumference for the headband, thus allowing the wearer to select a position that is comfortable yet secure.
The headband 22 further has a pair of front connecting arms 37a, 37b and a pair of rear connecting arms 40a, 40b. The connecting arms 37 may be shaped to have preferred bending lines or “living hinges” (as indicated, for example, at 43a, 43b), which allow the corresponding arm 37 to be bent approximately 90 degrees (e.g., from vertical to horizontal), and another set of bending lines (as indicated, for example, at 46a, 46b) which allow the corresponding arm 37 to be bent approximately a further 90 degrees (e.g., from horizontal to vertical) to join the headband 22 to the helmet shell.
As best seen in FIG. 5, the connecting arm 37b is joined through a hole 49 to the helmet shell 10 in the manner explained below, thereby allowing the connecting arm 37b to resist rotation. The headband 22 so connected is able to flex a small amount vertically, which brings the wearer's head into contact with the comfort pads 31 (see FIG. 3). In the horizontal plane, the headband 22 flexes only in the direction shown by the arrows in FIG. 4, i.e., approximately perpendicular to the shell at the points where the headband is joined to the shell. It is desirable that no two connecting arms have directions of flexure that are substantially parallel; in a headband configuration with four connecting arms, for example, the opposing arms are oriented so that the directions of flexure are not aligned with one another. In the preferred embodiment, at least two such connecting points are oriented so that the directions of flexure intersect at a point within the contour defined by the headband. This helps the headband resist displacement toward the helmet shell, keeping the wearer's head centered and therefore providing space for impact absorption.
FIG. 5 illustrates details of an exemplary mode of attaching connecting arm 37b to the helmet shell 10; connecting arms 37a, 40a and 40b have the same assembly components. The headband 22 is mounted to the shell 10 by passing the post 52 of an anchor 55 through hole 49 in the connecting arm 37b, and also through the hole 58 in the helmet shell 10, then securing it using the screw 15b. The off-round (e.g., polygonal—square, for exmaple—or angular) shape of the post 52 and the matching shape of the hole 49 allow the connecting arm to resist rotation within the hole 49. The anchor 55 may also include a contour 61 formed to match a complementary recession 64 molded into the connecting arm 37b to further aid in resisting rotation.
The attachment of the energy absorbing liner 28 to the helmet shell 10 may be accomplished by providing a tab 67 having a hole 70 therethrough. The tab 67 may be formed directly as part of the liner 28 if a material such as polypropylene is used for the liner 28, or co-molded if a softer material such as EPE is used. The attachment is made by passing the anchor post 52 through hole 70, thereby capturing the tab 67 between the connecting arm 37b and the helmet shell 10. A chin-strap component may be attached to the anchor 55 by passing the strap 13b through slot 73. A comfort band 76 made of a soft material, such as compressible urethane or EVA foam, may be added on the side of the headband 22 facing the wearer's head and secured using, for example, hook-and-loop fasteners to improve comfort.
Having described certain embodiments of the invention, it will be apparent to those of ordinary skill in the art that other embodiments incorporating the concepts disclosed herein may be used without departing from the spirit and scope of the invention. The described embodiments are to be considered in all respects as only illustrative and not restrictive.