Protective headguard

Abstract

Protective headguard comprising overlapped inner and outer layers attached so as to permit frictional sliding of at least one area of the outer layer over the inner layer.

Description

FIELD OF INVENTION

[0002] The present invention generally relates to protective headgear. Specifically, it relates to protective headgear intended to reduce angular acceleration of the human brain caused by an impact to the protective headgear.

BACKGROUND OF THE INVENTION

[0003] The prior art contains many examples of protective headgear or helmets intended to attenuate shock directed at the head. Protective headgear is used in many human sports and activities such as American football, Australian rules football, martial arts, equestrian sports, wrestling, cycling, lacrosse, baseball, hockey, inline skating, skateboarding, skiing, snowboarding, soccer, rock climbing and whitewater canoeing or kayaking. Protective headgear is also used in work activities such as construction, the military and firefighting.

[0004] Headgear is generally designed to protect the head from at least one of three kinds of impact. First, protective headgear may be intended to protect the wearer from penetrating objects. This is particularly true with military headgear. Second, headgear may be designed to protect the wearer from contact loading, i.e., loading at the point of impact. An injury from contact loading might be a skull fracture.

[0005] Third, headgear may be intended to protect the wearer from inertial loading, i.e., acceleration or deceleration of the brain from an impact to the head. There are two kinds of head acceleration that can occur in an impact. Acceleration of the head in a plane directed at the head's center of gravity is called linear or translational acceleration. Acceleration along an arc is called angular or rotational acceleration. Given the structure of the brain and skull, and the way they respond to forces, most biomechanical and medical research indicates that angular, rather than linear, acceleration causes relatively greater damage to the brain. See, e.g., Holbourn, A. H. S., “Mechanics of Head Injuries,” The Lancet, 2, 438-441 (1943); Ommaya, A. K. and Gennarelli, T. A., “Cerebral Concussion and Traumatic Unconsciousness: Correlations of Experimental and Clinical Observations on Blunt Head Injuries,” Brain, 97, 633-654 (1974). It has been demonstrated that padding can reduce angular acceleration of the head. See, Sances, A. and Kumaresan, S., “Padding in Child Restraint and Roll Bar Systems for Head Injury Reduction,” published at http://www.ataassociates.com/sances/index.html. However, the prior art contains few examples of padding or shock attenuation systems intended to manage changes in angular acceleration.

[0006] This lack of systems intended to manage changes in angular acceleration is significant. In many instances the materials or systems that best manage or modulate linear forces may not best manage or modulate angular forces. Moreover, since the head of a wearer of protective headgear may be subjected to both linear and angular acceleration in response to an impact, it is important that devices be developed that protect wearers from both linear and angular impact forces.

[0007] The few examples of materials and systems that do seek to protect wearers from linear and angular forces can be grouped as follows. The first group of protective headgear devices includes those devices wherein the padding is formed or constructed in a way to absorb angular forces. Such technologies take a material with certain properties and improve its ability to respond to shearing forces by shaping or forming the material in a certain way.

[0008] For example, U.S. Pat. No. 6,397,399 to Lampe et al. fits within this first category. The Lampe (399) patent discloses a headguard for use in sports such as soccer. The headguard has padding consisting of pillows or “nubbins” covering at least a portion of the forehead of the wearer. When angular forces are directed at the surface of the headguard, the nubbins bend allowing the exterior surface of the headguard to shift in the direction of the. angular force. This shifting may help modulate the angular acceleration of the head.

[0009] There may be practical limitations on the height of the pillows or nubbins for protective headgear. Given this, they may be best suited for applications where the angular forces are limited.

[0010] Another group of technologies includes devices wherein a material of a lower shear modulus (i.e., an elastic body) is positioned in headgear between a shell (i.e., a rigid outer layer) and a liner. This elastic body lowers the overall shear modulus of the protective layers. U.S. patent application, Pub. No. US 2001/0032351 to Nakayama et al., is an example of this. The Nakayama Application discloses a helmet with a rigid shell and inner liner. An elastic body, such as a gel, is positioned between the shell and the inner liner and “stuck” to the interior side of the shell and the exterior side of the inner liner. The elastic body would permit the shell to shift in relation to the liner when angular forces are directed at the helmeted head. To permit the shell to shift in all directions, the Nakayama patent discloses a spherical shaped shell and liner.

[0011] The device disclosed in the Nakayama Application has limitations. First, with a rigid shell or a rigid liner, rotation of that shell in relation to the liner can only effectively occur if both the shell and the liner are substantially spherical in shape. The head, however, is not spherically shaped. To create an inner liner with a spherically shaped outer surface would require adding substantial bulk to the liner. For many applications, therefore, the device contemplated by the Nakayama Application may be impractical. Second, rotation will be limited by the elasticity of the elastic body. Third, the resistance to shearing may increase as the elastic body is stretched. While this may be suitable for some applications, in others it may be desirable to have a more constant rate of resistance.

[0012] A final group of headgear intended to modulate angular acceleration of the head includes devices where the protective headgear as a unit can move on the surface of the head to attenuate angular forces. U.S. Pat. No. 6,247,181 to Hirsch et al. discloses a bandana type headband with foam encased by fabric. The non-rigidity of the device itself allows the inner surface of the headgear to move across the head in response to angular forces.

[0013] The capability of headgear to move in relation to the surface of the head is not unique to the device disclosed in the Hirsch Patent. Any protective headgear that fits less snugly or that has the capacity to deform and shift as a unit in response to an impact could perform the same function. However, the capacity for such a device to modulate angular forces may be difficult to predict or control since head shapes, moisture on the surface of the head, and hair may all affect this capacity.

[0014] There is a need therefore for a device that can respond to and help protect the head from relatively high levels of angular forces; that can be incorporated into a piece of headgear of less bulk and weight; and that could consistently provide protection to the head from angular forces.

SUMMARY OF THE INVENTION

[0015] Generally, the present invention relates to improvements to a headguard for athletes. A first aspect of the invention is a headguard comprising overlapped inner and outer layers attached so as to permit frictional sliding of at least one area of the outer layer over the inner layer.

[0016] A second aspect of the invention is a headguard comprising overlapped inner, intermediate and outer layers attached so as to permit frictional sliding of at least one area of the outer layer over the intermediate layer.

[0017] A third embodiment of the invention is a headguard comprising (i) overlapped inner and outer layers, and (ii) a flowable material intermediate the layers, wherein (iii) the inner and outer layers are attached so as to permit sliding of at least one area of the outer layer relative to the inner layer subject to drag exerted by the flowable material.

[0018] Objects and advantages of this invention include:

[0019] Protective headgear that reduces or modulates angular acceleration of the head by reducing or modulating rotational forces acting upon the head.

[0020] Protective headgear that can consistently reduce or modulate relatively high levels of rotational forces acting upon the head.

[0021] Protective headgear that not only reduces or modulates rotational forces but also modulates linear forces.

[0022] Protective headgear that is relatively lightweight.

[0023] Protective headgear that reduces or modulates rotational forces with at least two layers that at least at certain locations are not connected and that can slide in relation to one another at or near those unconnected locations.

[0024] Protective headgear where the ease with which the two layers can slide in relation to one another is regulated at the interface of those two layers. Examples of such regulating materials include:

[0025] Introducing fluids of either lower or higher viscosity between the layers to adjust the ease with which the layers can slide in relation to each other.

[0026] Introducing a gas between the layers to adjust the ease with which the layers can slide in relation to each other.

[0027] Inserting particles between the layers to adjust the ease with which the layers can slide in relation to each other.

[0028] Providing the layers with interfacing surfaces of greater or lesser smoothness to adjust the ease with which the layers can slide in relation to each other.

[0029] Inserting a third layer of material, such as a film interposed between the layers, to adjust the ease with which the layers can slide in relation to each other.

[0030] Modifying the texture of the interfacing surfaces of the outer and inner layers to adjust the ease with which the layers can slide in relation to each other.

[0031] Affixing rougher or smoother materials to one or both of the interfacing surfaces to adjust the ease with which the layers can slide in relation to each other.

[0032] Protective headgear in which the interfacing surfaces of the inner and outer layers may be but do not have to be spherical.

[0033] Protective headgear in which the sliding of the layers as the result of an impact permanently deforms the protective headgear.

[0034] Protective headgear in which the sliding of the layers as the result of an impact does not permanently deform the protective headgear. Examples of means for achieving such a recoverable repositioning of the layers include:

[0035] Construction of one or both layers from an elastic material.

[0036] Use of elasticity anchors (where the layers are connected).

[0037] Manual realignment of the layers to their original orientation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings.

[0039] FIG. 1 is a side elevation view of a first embodiment of the external configuration of the headgear worn by a wearer.

[0040] FIG. 2 is a side elevation view of a second embodiment of the external configuration of the headgear worn by a wearer.

[0041] FIG. 3 is a cross-sectional side view of one configuration of the layers used to form the headgear.

[0042] FIG. 4 is a cross-sectional side view of headgear having the external configuration of FIG. 1 with a deformable outer layer after localized deformation of a portion of the outer layer caused by application of an angular force upon the headgear.

[0043] FIG. 5 is a cross-sectional side view of the headgear having the external configuration of FIG. 1 with a rigid outer layer after sliding of the outer layer relative to the inner layer caused by application of an angular force upon the headgear.

[0044] FIG. 6 is a cross-sectional side view of the headgear having the external configuration of FIG. 1 with an interface layer between the inner and outer layers after deformation of the outer layer relative to the inner layer caused by application of an angular force upon the headgear.

[0045] FIG. 7 is a side elevation view of the headgear having the external configuration of FIG. 2 with a flexible outer layer after sliding of the front portion of the outer layer relative to the inner layer caused by application of an angular force upon the headgear.

[0046] FIG. 8 is a side elevation view of the headgear having the external configuration of FIG. 2 with a rigid outer layer after sliding of the outer layer relative to the inner layer caused by application of an angular force upon the headgear.

[0047] FIG. 9 is an exploded cross-sectional view of an embodiment of the inner and outer layers of the headgear with nodules on the interfacing surfaces of the layers.

[0048] FIG. 10 is a perspective view of the inner layer shown in FIG. 9.

[0049] FIG. 11 is an exploded cross-sectional view of another embodiment of the inner and outer layers of the headgear with “hair-like” projections on the interfacing surfaces of the layers.

[0050] FIG. 12 is a perspective view of the inner layer shown in FIG. 11.

[0051] FIG. 13 is an exploded cross-sectional view of yet another embodiment of the inner and outer layers of the headgear with spherical particles on the interfacing surface of the inner layer.

[0052] FIG. 14 is a perspective view of the inner layer shown in FIG. 13.

[0053] FIG. 15 is an exploded cross-sectional view of still another embodiment of the inner and outers of the headgear with irregular-shaped particles on the interfacing surface of the inner layer.

[0054] FIG. 16 is an exploded cross-sectional view of a final embodiment of the inner and outer layers of the headgear with an intermediate film between the inner and outer layers.

DETAILED DESCRIPTION OF THE INVENTION INCLUDING A BEST MODE

Nomenclature

[0055] 100 head of person

[0056] 101 headgear

[0057] 103 forehead area

[0058] 104 top of head

[0059] 105 temples

[0060] 106 ears

[0061] 107 back of head

[0062] 108 chinstrap

[0063] 109 headband embodiment

[0064] 121 rivet

[0065] 200 head of person

[0066] 201 headgear

[0067] 212 comfort liner

[0068] 213 inner layer

[0069] 214 outer layer

[0070] 215 interface

[0071] 300 head of person

[0072] 301 full coverage embodiment

[0073] 303 forehead area

[0074] 304 top of the head

[0075] 312 comfort liner

[0076] 313 inner layer

[0077] 314 outer layer

[0078] 315 interface

[0079] 320 force

[0080] 321 rivet

[0081] 322 crumpled area of outer layer

[0082] 323 areas remote from impact

[0083] 325 sliding

[0084] 328 edges of headgear

[0085] 400 head of person

[0086] 403 forehead area

[0087] 406 ears

[0088] 407 back of head

[0089] 409 headband embodiment

[0090] 413 inner layer

[0091] 414 outer layer

[0092] 415 interface

[0093] 420 force

[0094] 421 rivet

[0095] 425 sliding

[0096] 426 deformed area

[0097] 427 rotation

[0098] 513 inner layer

[0099] 514 outer layer

[0100] 515 interface

[0101] 530 nodules

[0102] 531 hair-like projections

[0103] 532 spherical particles

[0104] 533 non-spherical particles

[0105] 534 film

[0106] Construction and Use

[0107] FIGS. 1 and 2 are examples of protective headgear 101 and 109, respectively. FIG. 1 shows the head 100 of a person wearing a unitary piece of headgear 101 that covers the forehead area 103, the top of the head 104, the temples 105, the ears 106, and the back of the head 107. As shown in FIG. 1, an optional chinstrap 108 could help secure the headgear 101 to the head 100. FIG. shows a protective headband 109 that provides a band of coverage from the forehead area 103, over the temples 105, to the back of the head 107.

[0108] The purpose of these illustrations is not to exhaust the possible headgear configurations that could employ embodiments of the invention. Rather, the purpose is to show the many different kinds of headgear configurations could embody the invention.

[0109] FIG. 3 is a cross-section of the layers of one embodiment of the headgear 201 that could be present in any of the headgear embodiments, including the headgear embodiment 101 of FIG. 1 and the headband embodiment 109 of FIG. 2. Referring to FIG. 3, the invention can include an optional comfort liner 212 next to the head 200 of the wearer. The comfort liner 212 could be, for example, a lower density, open-cell foam material that easily conforms to the head 200 and provides sweat and heat management characteristics. The comfort liner 212 could also be made up of multiple open-cell foam pads (not shown). Many other kinds of material and configurations of material could be employed in a comfort liner 212.

[0110] The next layer could be the inner layer 213. The inner layer 213 could consist of padding intended to absorb some of the load of the impact, especially those with a linear component. It could have plastic or elastic characteristics, depending on the application. Plastic materials have been found to be more suitable for protection from single, high-energy impacts. Materials with plastic characteristics that are commonly used in protective headgear include ones made from polystyrene, polypropylene, or polyurethane. An elastic material should be more suitable for multiple, lower energy impacts where the headgear 101 or 109 needs to be re-used. A common material for such applications would be foams such as cross-linked polyethylene. However, other foams, gels, fluids, or gases sealed in film (not shown) would be suitable for many applications.

[0111] The outer layer 214 could also be the exterior layer or the shell. If the outer layer 214 were to act as a shell, it could be made of a rigid or semi-rigid material that distributes the load from an impact over a greater surface area of the inner layer 213. Suitable rigid or semi-rigid materials include polycarbonate, acrylonitrile-butadiene-Styrene (ABS), or fiberglass reinforced plastic (FRP). Materials suitable for forming a less rigid outer layer 214 include specifically, but not exclusively, foam, fabric or impregnated fabric.

[0112] The outer layer 214 (especially for linear impacts) may perform more of a load distribution function while the inner layer 213 may perform more of a load absorption function. These functional roles, however, are not essential to the invention. For example, it may be desirable in certain circumstances to have both the inner layer 213 and the outer layer 214 perform a load distribution function with a third layer (not shown) performing a load absorption function. In such an instance, both the inner layer 213 and outer layer 214 could be made of the same rigid or semi-rigid materials described above. Alternatively, both the inner layer 213 and outer layer 214 could perform load absorption functions. In this case both layers 213 and 214 could be made of the materials intended for energy absorption described above.

[0113] The inner layer 213 and outer layer 214 need not be innermost or outermost layer respectively. The inner layer 213 and outer layer 214 could be the only two layers in the headgear 201, or they could be two of many layers. Additionally, the inner layer 213 and outer layer 214may be composed of sub-layers. The descriptive terms inner and outer simply establish the relationship between two layers, with the inner layer 213 positioned closer to the head 100, 200, 300, 400 than the outer layer 214.

[0114] Referring to FIG. 3, the inner layer 213 cooperates with the outer layer 214 at the layer interface 215 defined by the exterior surface (unnumbered) of the inner layer 213 and the interior surface (unnumbered) of the outer layer 214.

[0115] At least at certain points at the interface 215, the inner layer 213 and outer layer 214 are not connected to each other. Thus, when the exterior surface (unnumbered) of the outer layer 214 encounters an oblique force, such as forces 320 and 420 shown in FIGS. 4-8, the exterior surface (unnumbered) of the inner layer 213 and the interior surface (unnumbered) of the outer layer 214 will slide in relation to one another. At other points the inner layer 213 and outer layer 214 are connected. These connection points are generically referred to herein as anchor points.

[0116] FIG. 4 depicts one embodiment of the invention subjected to an oblique force 320 having an angular vector (not separately shown). The headgear 301 in this embodiment covers the top of the head 304 and could be the same as the one shown in FIG. 1. In addition, the embodiment of the headgear 301 shown in FIG. 4 could have the same layers as those depicted in FIG. 3, (i.e., an outer layer 314, an inner layer 313, an interface 315, and a comfort liner 312). The headgear 301 of the embodiment shown in FIG. 4 includes a rivet 321 attaching the inner layer 313 and the outer layer 314 to each other at a single anchor point. Many other kinds of fasteners suitable for use in forming an anchor point are known to those skilled in the art, including specifically but not exclusively, sewn seams, adhesives and heat welding.

[0117] The location of the anchor points could be varied. By way of example, FIG. 2 shows an alternative location for the anchor points wherein rivets 121 are located on opposite the sides of the headgear 109 just above the ears 106. Other anchor point locations might also be desirable.

[0118] As shown in FIG. 4, the outer layer 314 may be formed of a material which is relatively non-rigid and therefore could be deformed when subjected to an oblique force 320 as evidenced by the crumpled area 322 over the forehead 303 of a wearer. Crumpling of the outer layer 314 is particularly desired when the inner layer 313 and outer layer 314 are anchored with a fastener, such as rivet 321, which is not elastic. Such crumpling allows the interior surface (unnumbered) of the outer layer 314 to slide 325 in relation to the exterior surface (unnumbered) of the inner layer 313 even though the fastener (e.g., rivet 321) rigidly attaches the inner layer 313 and the outer layer 314 at the anchor points.

[0119] FIG. 5 shows an embodiment of headgear 301 similar to the headgear 301 shown in FIG. 4 subjected to an oblique force 320. The outer layer 314 on the headgear 301 depicted in FIG. 5 is more rigid than the outer layer 314 on the headgear 301 depicted in FIG. 4. Hence, the outer layer 314 does not crumple when subjected to an oblique force 320. Rather, an elastic rivet 321 is employed at the anchor point, allowing the rivet 321 to stretch and thereby allow the interior surface (unnumbered) of the outer layer 314 to slide 325 in relation to the exterior surface (unnumbered) of the inner layer 313 proximate the point of impact (unnumbered), even though the outer layer 314 is not appreciably deformed by the oblique force 320. The outer layer 314 may be lifted off the inner layer 313 at areas remote from the point of impact, such as represented by arrows 323 in FIG. 5.

[0120] FIG. 7 shows another embodiment of the invention in the form of a headband 409. The headband 409 is represented as subjected to an oblique force 420. In this embodiment of the invention, the inner layer 413 and outer layer 414 are attached to each other at two laterally aligned anchor points by rivets 421 positioned just above each ear 406. The outer layer 414 depicted in this embodiment is constructed of a relatively non-rigid material which will deform when subjected to an oblique force 420 as evidenced by the deformed area 426. The inner layer 413 and outer layer 414 may be securely attached to one another, such as by an adhesive (not shown); over that portion (unnumbered) of the headband 409 covering the back 407 of the head 400 to ensure that deformation occurs about the anchor points. Deformation about the anchor points causes the interior surface (unnumbered) of the outer layer 414 to slide 425 in relation to the exterior surface (unnumbered) of the inner layer 313 only on that portion of the headband 409 covering the forehead area 403.

[0121] Referring to FIG. 8, the headband 409 may alternatively be constructed without attaching the inner layer 413 and the outer layer 414 at the back 407 of the head 400. Such an embodiment permits the entire outer layer 414 to rotate 427 as a unit about the rivets 421, resulting in sliding 425 of the front (unnumbered) and back (unnumbered) portions the interior surface (unnumbered) of the outer layer 415 over the exterior surface (unnumbered) of the inner layer 413. The amount of rotation 427 can be controlled by controlling the tightness of the rivets 421.

[0122] Referring to FIG. 6, at least a portion of the interface 315 may optionally be sealed, such as by fusing the inner layer 313 and the outer layer 314 along the edges 328 and the interface 315 filled with a flowable material (unnumbered) such as solid particulates, liquid,gel or gas. When such a “filled” headgear 301 is subjected to an oblique force 320, the interior surface (unnumbered) of the outer layer 314 will slide in relation to the exterior surface (unnumbered) of the inner layer 313 by deformation of the inner layer 313 and/or the outer layer 314, thereby causing the fluid to flow within the sealed interface 315 such as represented in FIG. 6. The thickness of the filled interface 315 may be selected as necessary to achieve the desired effect, with a thickness of just a few thousandths of an inch suitable for many applications. The flow properties of the fluid retained within the sealed interface 315 will affect the ease or difficulty with which the outer layer 314 will slide in relation to the exterior surface (unnumbered) of the inner layer 313. For example, a high viscosity fluid might inhibit sliding, while a low viscosity fluid might facilitate sliding.

[0123] Particles (not shown) may optionally be suspended in the fluid retained within the sealed interface 315 to achieve a desired flow characteristic. When particles are incorporated into the fluid, the fluid preferably has a higher viscosity for purposes of facilitating long-term suspension of the particles in the fluid.

[0124] The ease or difficulty with which the interior surface (unnumbered) of the outer layer 214, 314, 414, 514 slides relative to the exterior surface (unnumbered) of the inner layer 213, 313, 413, 513 (hereinafter “slide control”) can be controlled in any number of ways. One variable which can be altered to effect slide control is the rigidity of the inner layer 213, 313, 413, 513 and/or the outer layer 214, 314, 414, 514. Another is the elasticity of the mechanism attaching the layers at each anchor point.

[0125] Another variable which can be altered to effect slide control is the frictional properties at the interface 215, 315, 415, 515 between the inner layer 213, 313, 413, 513 and/or the outer layer 214, 314, 414, 514. Several specific means for effecting a specific frictional property at the interface 215, 315, 415, 515 are shown in FIGS. 9-16. FIGS. 9 and 10 show nodules 530 on the interior surface (unnumbered) of the outer layer 514 and the exterior surface (unnumbered) of the inner layer 513. FIGS. 11 and 12 show hair-like projections 531 (e.g., felt) on the interior surface (unnumbered) of the outer layer 514 and the exterior surface (unnumbered) of the inner layer 513. FIGS. 13 and 14 show spherical particles 532 on the exterior surface (unnumbered) of the inner layer 513. FIG. 15 shows irregular shaped particles 533 on the exterior surface (unnumbered) of the inner layer 513. FIG. 16 shows an intermediate film 534 positioned between the interior surface (unnumbered) of the outer layer 514 and the exterior surface (unnumbered) of the inner layer 513. Other embodiments would also be known to those skilled in the art.

[0126] An additional advantage recognized with the hair-like projections 531 and the nodules 530 is the ability of such features to absorb an oblique force by toppling or collapsing when subjected to such a force.

[0127] The present invention should not be considered limited to the particular examples described above, but rather should be understood to cover all aspects of the invention as fairly set out in the claims arising from this application. For example, while suitable sizes, materials, fasteners, and the like have been disclosed in the above discussion, it should be appreciated that these are provided by way of example and not of limitation as a number of other sizes, materials, fasteners, and so forth may be used without departing from the invention. Various modifications as well as numerous structures to which the present invention maybe applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the present specifications. The claims which arise from this application are intended to cover such modifications and structures.

Claims

1. A protective headguard, comprising overlapped inner and outer layers attached so as to permit frictional sliding of at least one area of the outer layer over the inner layer.

2. A protective headguard, comprising overlapped inner, intermediate and outer layers attached so as to permit frictional sliding of at least one area of the outer layer over the intermediate layer.

3. A protective headguard, comprising (i) overlapped inner and outer layers, and (ii) a flowable material intermediate the layers, wherein (iii) the inner and outer layers are attached so as to permit sliding of at least one area of the outer layer relative to the inner layer subject to drag exerted by the flowable material.

4. The protective headguard of claim 3 wherein the flowable material is solid particulates.

5. The protective headguard of claim 3 wherein the flowable material is a gel.

6. The protective headguard of claim 3 wherein the flowable material is a liquid.

7. The protective headguard of claim 3 wherein the flowable material is a gas.

8. The protective headguard of claim 1 wherein the inner and outer layers are biased towards a standard position relative to one another.

9. The protective headguard of claim 2 wherein the inner and outer layers are biased towards a standard position relative to one another.

10. The protective headguard of claim 3 wherein the inner and outer layers are biased towards a standard position relative to one another.

11. The protective headguard of claim 1 wherein the inner and outer layers are attached by elastic material.

12. The protective headguard of claim 2 wherein the inner and outer layers are attached by elastic material.

13. The protective headguard of claim 3 wherein the inner and outer layers are attached by elastic material.

14. The protective headguard of claim 1 wherein the inner layer is elastic.

15. The protective headguard of claim 1 wherein the inner layer is inelastic.

16. The protective headguard of claim 1 wherein the outer layer is elastic.

17. The protective headguard of claim 1 wherein the outer layer is inelastic.

18. The protective headguard of claim 2 wherein the inner layer is elastic.

19. The protective headguard of claim 2 wherein the inner layer is inelastic.

20. The protective headguard of claim 2 wherein the outer layer is elastic.

21. The protective headguard of claim 2 wherein the outer layer is inelastic.

22. The protective headguard of claim 1 wherein the inner and outer layers each have an interfacing major surface and at least one of the interfacing surfaces has a rough texture.