# Patent

## Title
Protective head covering having impact absorbing crumple or shear zone

## Abstract

A helmet construction for protecting a user's head, and the brain within the cranium from impact forces, includes a shell contoured to the shape of the user's head, with cushioning along at least part of the shell interior and a chinstrap. The shell consists of three (or more) discrete panels that are physically and firmly coupled together providing rigid protection under most circumstances, but upon impact the panels move relative to one another, but not relative to the user's head, thereby permitting impact forces to be dissipated and/or redirected away from the cranium and brain within. Upon impact to the helmet, there are sequential stages of movement of the panels relative to each other, these movements initially being recoverable, but with sufficient vector forces the helmet undergoes structural changes in a pre-determined fashion, so that the recoverable and permanent movements cumulatively provide a protective ‘crumple zone’ or ‘shear zone’. The first two stages of protection arise from the design of the fasteners that have the ability to invaginate and collapse within themselves, and their design having a 45 degree angle, which will allow movement of a region of connected panels to translate along the fastener shaft. Both of these movements will be recoverable and provide a ‘functional crumple zone’. The final stage of protection arises from the braking function of the pins, as they are forced from one aperture through to the next, the direction and extent of which is determined by the impact force and direction. This final level of panel movement and protection is not recoverable and thus provides a ‘structural crumple zone’. Finally the fastener size and thickness, together with the thickness of webbing and distance between apertures, functions to provide varying degrees of resistance to impact forces, thus making the helmet design suitable for activities with different levels of impact speed and risk potential.

## Background
RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent application Ser. No. 10/372,938, filed 26 Feb. 2003, now U.S. Pat. No. 6,751,808, and entitled “Sports Helmet Having Impact Absorbing Crumple or Shear Zone”.


SCOPE OF THE INVENTION
The present invention relates to a protective head covering which, for example, may be used as a hard hat or sports helmet and which is characterized by two or more parts or panel sections which are joined so that upon the application of a minimum impact force, the parts permit predetermined and controlled movement relative to each other in increments, via a series of mechanisms, to function overall as an impact absorbing ‘crumple’ or ‘shear zone’.
Thus while providing the usual protection to the head from puncture or direct compressive force, this helmet will provide unique additional and much needed protection by absorbing and/or redirecting the impact forces across the skull, rather than transferring them through the cranium to the brain inside, as currently is the norm. If an egg is shaken hard, the yoke will break inside, as the transfer of forces cause the yoke to dash upon the insides of the shell, while the shell itself remains undamaged. Known as a ‘contre' coup’ injury, this is how ‘shaken baby syndrome’ injuries occur and is well documented as the mechanism of injury most responsible for the majority of brain trauma; not actual skull fractures. It is inherent in any fall or impact to the head and urgently needs to be addressed in helmet design. This helmet will function to prevent this analogy happening to the delicate brain, which like the yoke is surrounded by fluid within a hard and unyielding shell, or cranium.
BACKGROUND OF THE INVENTION
The use of helmets to protect the head from injury has been done through the centuries, and for a variety of activities ranging from warfare to the more common uses today of sports and recreation. Typical helmet construction consists of a rigid or semi-rigid shell formed into a generally domed-shape, which covers the majority of the user's head and frequently incorporates a chinstrap to secure the shell in the preferred position on the head. Depending upon the shell construction, padding or cushioning may also be provided along the inside of the shell for increased comfort, better fit and to assist in the absorption of any impact forces.
Helmets from their first use to today, have essentially been an artificial skull over the human skull and thus only duplicate the same protection the natural skull is already providing, without adding any more safety dimensions. In fact, the extra ‘skull’ serves to increase the weight of the head relative to the neck muscles, which is well-researched cause of both soft tissue and bone injuries. More important for injuries, this additional weight increases the acceleration potential ((increased) mass×velocity) of the brain inside the cranium, after impact.
Conventional helmets are formed from molded semi-rigid polystyrene or StyrofoamTM bonded to a plastic outer skin, or the hard rigid shell is lined with soft padding. There is an important disadvantage and negative safety feature inherent with both of these common conventional helmet styles. In order to provide sufficient protection from impact forces, heretofore it has been the practice of the helmet manufacturers to form the polystyrene shell layer with a thickness of one inch or more, and if the padding is for comfort it is often of similar thickness. As a result, when worn, these sports helmets project outwardly a distance of two inches or more from the wearer's head, increasing the diameter of the natural skull and adding physical disproportion of head to shoulder/torso, for optimal muscular control.
Upon impact from anything other than a true perpendicular force vector, the skull/helmet combination acts as a fulcrum as the neck and body ‘bends’ around it. With increased diameter, the range and magnitude of ‘bend’ at the fulcrum is dramatically increased and ultimately, the quantity and quality of associated injuries. This is one of the most common ways for avulsion of bone, discs and muscles and it is the classical method for cervical nerve root stretch, rupture or avulsion. Termed a ‘zinger’ in its mild, temporary form, permanent total nerve loss results when the ‘bending’ injury is more severe. Larger diameter and/or added weight invariably increase rotational force potential and rotation, according to whiplash research, is the most destructive.
SUMMARY OF THE INVENTION
Accordingly, the present invention strives to overcome some of the disadvantages of prior art helmets by a) providing a protective head covering or helmet that is closer in weight and size to the user's anatomical head, thereby minimizing resultant disproportion between the head with helmet and the neck/torso and by b) redirecting or dissipating injurious forces away from the head and brain, by using interlocking component panels that will move relative to each other in predetermined directions and increments, effectively producing a ‘crumple zone’ or ‘shear zone’.
A practical advantage with this invention that also improves safety, is that the three discrete portions or panels, enable better customizing to fit different head shapes such as oval, oblong and round, not just adapt to sizes. Parents will be able to customize the helmets as their children grow, thus avoiding the understandable but dangerous habit of buying large so that the child will ‘grow into it’. A frontal fall in a helmet that is too large, forces the helmet backwards and can force the back of the helmet into the neck at the base of the skull, at the anatomical area of the brain stem, with tragic results often worse than if a helmet had not been worn at all.
A very important safety feature of this design is that because of the interlocking panels, absorbing or re-directing force vectors along predetermined, incremental stages, any rotational vectors at the time of impact will be decreased or actually changed to linear vectors, thereby reducing the risk of the very damaging rotational injuries to the nerve roots and/or brain stem. This helmet is designed to absorb kinetic and/or potential energy at the time of the fall/impact, and transfer it along more controlled, less damaging vectors away from the head and brain.
A practical consideration is that this helmet design will be lightweight, comfortable and versatile enough to accommodate not only most recreational and sporting activities including bicycling, snowboarding, skateboarding, roller blading, horseback riding and with minimal modifications to protect the face, more aggressive activities such as hockey and football, but also will provide head protection as a motorcycle helmet, as an army helmet in military applications, or as a hard hat in construction and mining applications. Thoughts have been given to aesthetics, since a helmet cannot protect if it is not worn and thus, especially for the high risk, energetic youths, this design allows for simple dressing with caps to provide ‘visual appeal’.
There has been a desperate call from the professional community treating head injuries, for a radically different helmet design, away from the ‘skull over the skull’ concept, to one that incorporates current knowledge of how head, neck and especially ‘contre' coup’ injuries occur. The design of this helmet focuses first on accepted injury mechanisms and then simulates some of the effective structural features used in automobiles to reduce passenger injuries and some used in building structures to reduce earthquake damage. If the impact is severe enough, the final stages of the helmet ‘crumple zone’ will allow structural alterations, similar to vehicle crumple zones, thereby minimizing transfer of injurious forces to what it is protecting.
This helmet basic design includes an ‘I’ shaped central convex shaped component extending across the vertex/top of the skull, with the shorter extensions covering the forehead and base of the skull. In addition to this, there are two lateral convex components covering the sides of the skull, which interlock and join the centrepiece to complete the helmet. The three panels may be physically joined together in several ways concurrently, including a slot/tab arrangement or through the use of mechanical fasteners such as permanent or removable screws, pins, clips and/or rivets and the like. The slots/tab configurations and the fasteners allow incremental, predetermined movement, between the component parts upon impact.
The final sizing of helmet and extent to which it covers the user's forehead, occiput or temporal/lateral area of the skull, will depend somewhat to the degree of head protection sought for that particular activity or sport. However the construction will ensure a standard of skull coverage, which will offer the customary head protection, in addition to the much needed improvements with the moving panels
Where, for example, this design is to be used as a bicycle, roller blading or horseback-riding helmet, typically the sides of the shell portion would not extend below the user's ear or below the base of the skull at the back. Where the helmet is modified for use in other more aggressive and/or higher speed sports, or to suit military needs, it is to be appreciated that the helmet configuration would be adapted to provide increased coverage to the user's head, typically by extending in the rear beyond the base of the user's skull and laterally at least to the user's cheek bones on each side.
The ‘crumple zone’ or ‘shear zone’ characteristic of this helmet design is accomplished through overlapping levels of protection, where each aspect addresses a specific range of impact magnitude which when exceeded, transfers the forces to the next level of protection. The pins or rivets connecting the two lateral helmet panels to the central one and the many holes for them, contribute to the first two (possibly three) levels of protection, as a result of their structure, orientation and when impact forces are very high, their strength/ability to break though from the hole they were in, to the adjacent one(s). All of these levels of protections function within the helmet structure and design, leaving the head and skull inside as little involved as possible.
The convex, central panel will have two layers of material, separated by a small space that is greatest at the vertex and decreases towards the edges where the two pieces ultimately merge into a solid, double thickness. While the overall shape will be similar to the letter ‘I’ there will be perpendicular finger like projections along it's length, and these projections will be the means whereby the central panel is connected to the two lateral panels.
The two lateral components, also generally convex, will similarly consist of two layers that are separated by a small space, but in these panels the space will be negligible at the inferior margins, widening increasingly towards the superior aspect, where the space would remain open just enough to admit the finger like projections from the central panel, thereby completing the full head helmet. The projections along the length of the central panel will invaginate between the two layers of the lateral side panels, being firmly fastened by means of rivets or pins.
There will be pins/rivets firmly attached at all of the central panel projections, where the double thickness has merged until there is no longer air space between. These central panel projections will with many location choices of complementary holes in the lateral panels, connect and complete the full head helmet. This provides exceptional customization, not only to the size of the wearer's head but also to the shape, be it round, oblong, oval, broader at the front or otherwise. The holes not used to fix the three panels together, along with the spaces between the fingers like projections will additionally function for ventilation and cooling; an important feature since almost three-quarters of body heat is given off at the head.
The pins/rivets used for this helmet will have two pieces that screw together, thereby joining the lateral and central helmet panels as the two pieces of the rivet are fastened together, possibly allowing some internal residual motion between the two pieces of rivet. The pins/rivets might be attached at an angle such as forty-five degrees, and although secure once fastened, these pins/rivets could be disassembled, to readjust helmet size and shape. The protective mechanisms would engage in stages and summate to form the ‘crumple zone’ when necessary for optimal protection of the delicate head and brain within.
With impact at a side panel over the ear for example, the pins/rivets first hold firm; then allow some internal movement at the site joining the lateral and central panel projections; then if the pins/rivets are angled and the force vectors are strong enough, the impacted panel would be ‘shifted’ somewhat along the specific direction and linear line of the angled pin/rivet; and finally when the impact is very severe, the pin/rivet would break through to the adjacent hole(s), thereby braking or reducing the overall magnitude of the impact force. It is to be appreciated that the fastener/projection contact and subsequent projection deformation, allow the panels to move relative to each other, and more preferably so that the fastener assumes an orientation located at least partially in a next adjacent opening. It is to be appreciated that the relative movement of the panels and the deformation of the webs act to gradually dissipate the energy of the impact force, without translating the energy to the wearer's skull and more important the brain.
Current testing standards for helmets is to drop them from a height and if they do not crack or break, they are approved, but as previously mentioned, most head injuries from recreational or sporting activities are not associated with skull fractures. It is easy to visualize what would happen to the egg or egg yolk simulating the human brain, even if carefully packed and padded within any helmet, when tested in this fashion. Internationally the medical experts and professionals who treat head trauma are calling for a revolutionary new approach to protecting the head and brain, and this helmet design offers one. While enhancing the inherent protection provided by the human skull, this unique design also addresses the need to protect the brain inside the skull, by dampening forces, not transferring them across the cranium and by re-directing force vectors across the skull, not through it.
By means of interlocking, invaginating and force re-directing panels, this helmet design remains closer to the natural head size and weight thereby; a) avoiding the increased injury risks noted above and b) providing equitable skull protection for simple direct impact and most important of all c) uniquely minimizing the most common and destructive ‘contré coup’ injuries.
Accordingly, in one aspect the present invention resides in a helmet for protecting a user's head from impact forces, said helmet comprising,
a generally dome shaped shell, said shell being formed from a rigid or semi-rigid material and sized and contoured to cover a surface of said user's head to be protected, said shell including a first portion and a second portion,
a plurality of apertures formed through a region of said first portion,
said second portion including at least one locating opening formed therethrough and positioned to align with a selected one of said apertures when part of said second portion is located substantially in overlying juxtaposition with said first portion, and
a fastener sized for insertion through said opening and said selected one of said plurality of apertures to couple the first portion to the second portion,
said apertures being delineated from a next immediately adjacent aperture by a web member, said web member having a thickness selected to deform upon the application of a predetermined minimum force to at least one of said first portion and said second portion, and whereby the deformation of a web enables relative movement of the fastener from the selected one of said apertures into a next adjacent aperture and the limited movement of said first portion relative to said second portion.
In another aspect, the present invention resides in a protective head covering for protecting a user's head comprising a generally rigid shell, the shell including a central portion and at least one side portion,
the central portion being elongated in a forward longitudinal direction and contoured so as to substantially cover the upper front and rear portions of said user's head, and
first one of said side portions being sized to cover a respective side of said user's head and having an edge portion positioned in overlying juxtaposition with a respective longitudinal edge region of said central panel,
a first array of a plurality of apertures being formed through the peripheral region of the first said side portion and a first longitudinal edge portion of the central portion and at least one locating opening formed through the other of the edge portion of the first said side panel and said first longitudinal edge region at a location selected to enable the alignment of the at least one opening with a selected one of said apertures,
at least one coupling member for insertion in an opening and said selected one of said apertures aligned therewith to couple said first said side portion to said central portion,
each of the apertures in said first array being separated from a next adjacent aperture by a web member having a thickness selected whereby the application of a predetermined minimum force to one of said first side portion and the central portion results in the limited movement of the central portion relative to said first side portion, and the movement of the coupling member in the direction of impact forces against the web member which defines the selected aperture so as to deform the web member and move into at least one next adjacent aperture.
In a further aspect, the present invention resides in a helmet for protecting a user's head from frontal and side impacts, said helmet comprising,
a generally dome shaped shell, said shell sized and contoured to substantially cover said user's head, and including three discrete interconnected portions,
a first one of said portions comprising a central member elongated longitudinally so as to extend across front and rear portions of said user's head,
said remaining portions comprising first and second side members for overlying a respective side portion of said user's head,
a peripheral edge portion of said first side member provided in overlying juxtaposition with a first longitudinal side portion of said central panel,
a peripheral edge portion of said second side member provided in overlying juxtaposition with a second other longitudinal side portion of said central panel,
at least one of the first longitudinal side portion and said first side member including a first array of a plurality apertures formed therethrough,
the other one of said first longitudinal side portion and said first side member including a locating opening positioned so as to align with a selected one of said plurality of apertures in said first array, and
at least one of the second longitudinal side portions and the second side member including a second array of a plurality of apertures formed therethrough,
the other of said second longitudinal side portion and said second side member including a locating opening positioned so as to align with a selected one of said plurality of apertures in said second array,
a plurality of fasteners sized for insertion through each of said openings and said selected apertures aligned therewith to couple the first and second side members to the central member,
wherein the plurality of apertures of each of said first and second arrays are delineated from a next immediately adjacent aperture by a web member having a lateral thickness selected to deform upon the application of a predetermined minimum force, and whereby the application of said predetermined minimum force by said fastener deforms said web member and enables both relative sliding movement of the fastener into a next adjacent aperture and the limited relative movement of the interconnected portions.



BRIEF DESCRIPTION OF THE DRAWINGS
Reference will now be had to the following detailed description taken together with the accompanying drawings in which:
FIG. 1 shows a perspective view of a bicycle helmet construction in accordance with a first preferred embodiment of the invention, as used in position on a user's head;
FIG. 2 illustrates a cross-sectional view of the helmet construction shown in FIG. 1 taken along lines 2—2;
FIG. 3 illustrates a partial exploded perspective view of the helmet construction of FIG. 1 showing the manner of interconnecting the panels;
FIGS. 4a and 4b illustrate partial perspective views showing the limited relative movement of the shell panel portions in the absorption of impact forces;
FIGS. 5a and 5b illustrate cross-sectional views showing the limited relative movement of the panel portions in absorbing a side impact force;
FIG. 6 illustrates a partial exploded perspective view of a helmet construction in accordance with a further embodiment of the invention;
FIG. 7 illustrates a perspective view of a bicycle helmet construction in accordance with another embodiment of the invention; and
FIG. 8 illustrates an alternate construction for a connecting fastener used in securing the panel portions of the helmet construction of FIG. 7.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference may first be had to FIG. 1 which illustrates a bicycle helmet construction 10 for use in protecting a user's head 12 from impact forces, which for example would occur if the wearer was struck by a car or otherwise was thrown from a bicycle (not shown). The helmet construction 10 includes a generally domed shaped shell 14 which is secured in place on top of the user's head 12 by a releasable chin strap 16. The chin strap 16 is of a conventional two-piece design and is secured at each of its ends 18a,18b (FIG. 2) to a respective longitudinal side portion of the shell 14. As shown best in FIG. 2, the shell 14 has a size and contour selected so as to substantially cover the top of the user's head 12 and extends symmetrically in the front to back direction about a vertical central axis A–A1 (FIG. 2). The inner surface 20 of the shell 14 which is immediately adjacent to the user's head 12 is lined with strips of resiliently compressible foam cushioning 22. The cushioning 22 assists in maintaining the shell 14 comfortably in the correct position on top of the user's head 12 and furthermore, advantageously acts to assist in the absorption of impact forces.
The shell 14 is composed of three separate or discrete panels 26,28,30 which, as will be described, are interconnected to provide the shell 14 with its contoured dome shape. Each of the panels 26,28,30 are made of rigid or semi-rigid plastic which is generally curved to a corresponding portion of the user's head, and have a cross-sectional thickness selected to provide the desired degree of impact protection. In the case of a bicycle helmet, the plastic used to form the panels 26,28,30 would have a cross-sectional thickness of about 1 to 2 mm, however, thicker or thinner panel constructions could be used. As shown in FIG. 2, the panel 26 which covers the right side of the user's head 12 is formed in the mirror construction to the panel 30 used to cover the left side. The panels 26,28,30 are interconnected by physically coupling the right side panel 26 and the left side panel 30 to the central panel 28 by a series of two-piece rivets 38. As shown best in FIG. 3, the rivets 38 are configured to be assembled in a releasable screw-fit arrangement and include a male portion 40 and a female portion 42. Both portions 40,42 of the rivet include a respective shaft 44 and an enlarged diameter head 46. The shaft 44 of the male portion 40 is characterized by an externally threaded tip. The shaft 44 of female portion 42 includes an internally threaded socket sized to receive the threaded tip of the male potion 40 in a screw fit.
FIG. 2 shows best the right side and left side panels 26,30 as being formed with a double sidewall 50a,50b construction. The sidewalls 50a,50b of each panel 26,30 are spaced apart in a generally parallel relationship to each other, and merge at an outermost edge bight 52. The sidewalls 50a,50b and bight 52 defining an interior cavity 56 which is open along an innermost edge 58 spaced closest towards the axis A–A1. FIG. 3 shows best the innermost edge 58 of each side panel 26,30 as including three longitudinally spaced cut-outs or recesses 60a,60b,60c. The recesses 60,60b,60c extend inwardly through both sidewalls 50a,50b a distance towards the bight 52 and delineate four remaining tab portions 62a,62b,62c,62d which, as will be described, in assembly overlap part of the central panel 28.
The central panel 28 extends in the longitudinal direction from its front edge 64 at about the brow of the user's head 12 rearwardly to rear edge (not shown) at about the base of wearer's skull. In the lateral direction, the panel 28 is symmetrical about the axis A–A1 and most preferably spans between generally parallel longitudinal edge portions 66 spaced generally above the user's ears 69 (FIG. 2). Three recesses 68a,68b,68c (FIG. 3) extend inwardly towards the axis A–A1 from each respective side edge portion 66 of the panel. As shown in FIG. 1, the recesses 68a,68b and 68c are formed with a complementary size and spacing selected so as to align with the recesses 60a,60b,60c of a respective side panel 26,30 when the panel sections 26,28,30 are interconnected, so as to form ventilation holes (71) through the shell 14. If desired, however, additional ventilation holes could also be provided through one or more portions of the central panel 28 and/or either both side panels 26,28. The recesses 68a,68b,68c also function to delineate four outwardly projecting tab portions 70a,70b,70c,70d along each side portion 66.
As seen best in FIG. 1, four arrays of aligned apertures 72a,72b,72c,72d are formed through both sidewalls 50a,50b of each tab portion 62a,62b,62c,62d, respectively, in each panel 26,30. FIGS. 4a and 4b show best the arrays 72a–d as each consisting of a number of adjacent larger central openings 74. The central openings 74 each having a radial diameter which is selected greater than the diameter of the shaft 44 portions of each rivet 38, but less than the diameter of the rivet heads 46. A series of smaller peripheral openings 76 are provided extending radially about the central openings 74. The smaller openings 76 have a diameter which is selected smaller than the diameter shaft portions 44 of the rivets 38. Similarly, an array of apertures 80a,80b,80c,80d is formed in each respective tab portion 70a,70b,70c,70d along each longitudinal side 66 of the central panel 28. For clarity, FIG. 3 shows only the aperture arrays 72b formed in panel 26 together with an aperture array 80b formed in the adjacent portion of the central panel 26. The aperture arrays 80a–d of the central panel 28 are shown having a series of larger diameter central openings 82 (FIG. 3) surrounded by smaller peripheral openings 84 which correspond in size and positioning to the pattern of openings 74,76 in the array 72b of the side panel 26. It is to be appreciated that although FIG. 3 illustrates the aperture array 80b and the adjacent aperture array 52b of the panel 26 for clarity, it is to be appreciated as is shown in FIG. 1, each longitudinal side of the central panel 28 is provided with a corresponding number of aperture arrays 80a,80b,80c,80d corresponding to those of the panels 26,30.
FIGS. 5a and 5b show best the central openings 74 and 76 of the arrays 72a,72b as extending through both of the sidewalls 50a,50b in an aligned orientation. The openings 74,76 are defined by and separated from a next immediately adjacent opening 74 or 76, by a web 90 of plastic which is used to form the shell 14. The webs 90 have a lateral extent having regard to the thickness of the sidewalls 50a,50b selected to permit the deformation of the web 90 upon a predetermined minimum force (shown by arrow 100 in FIGS. 4a and 5b). As with the openings 74,76, the openings 82,84 of the aperture arrays 80a–d are also delineated from a next immediate opening 82,84 by a like web 90 of plastic used in the formation of the central panel 28. The webs 90 of the central panel 28 have a lateral extent and thickness selected so as to preferably permit their deformation upon the application of the predetermined minimum force 100 thereto.
As shown best in FIG. 3, the use of removable rivets 38 advantageously permit adjustment in the relative positioning of the shell panels 26, 28 and 30. This adjustable positioning enables the helmet assembly 10 to be fitted to differing sized heads 12. In particular, in assembly of the shell 14, the outer tab portions 70a–d of each side 66 of the central panel 28 are fitted between the sidewalls 50a,50b and into the interior cavity 56 of each side panel 26,30, respectively. The panels 26 and 28, and 28 and 30 are positioned so that the aperture arrays 80a,80b,80c,80d in each peripheral edge portion 66 at least partially align with respective aperture arrays 72a,72b,72d,72d formed through the panels 26,30. Once so positioned, the panels 26,28 are moved relative to the central panel 28 either towards or away from the axis A–A1 to achieve the desired fit for the helmet assembly 10 with at least one selected larger opening 74a,82a in each array 72a,80a, 72b,80b, 72c,80c and 72d,80d aligned. Once the desired relative positioning of the shell panels 26,28,30 has been achieved, the shaft 44 of the male portion 40 of the rivets 38 are inserted through the selected aligned openings 74a,82b (FIG. 5a) and the female portion 42 of the rivet 38 is thereafter coupled thereto by the threaded engagement of the socket with the threaded tip of portion 40. Although not essential, most preferably, the enlarged heads 46 of the male and female portions 40,42 of each rivet 38 are offset relative to each other. As shown best in FIG. 3, the rivet head offset is selected so that the shaft 44 of the assembled rivet 38 extends generally in a direction inclined in the direction of a likely impact force (shown by arrow 100).
The helmet assembly 10 advantageously acts to absorb and dissipate an impact force 100 without the requirement of thick layers of padding or cushioning. It is to be appreciated, that the shell 14 may thus be provided with a comparatively smaller profile than a conventional bike helmet and, for example, could be formed so as to extend less than two inches, and more preferably less than one inch beyond the radial extent of each side of the wearer's head 12.
In particular, as shown best in FIGS. 4 and 5, upon the application of a predetermined minimum impact force (arrow 100) which, for example, could be selected as the force which occurs when a user falls and strikes his head 12 against an object, the impact force 100 acts on the panel 26 (or alternately the panel 28 or panel 30, depending upon the point of impact). The impact of a force 100 exceeding the predetermined minimum force results in the movement of the panel 26 in the direction of arrow 120 (FIG. 5b) relative to the panel 28. In particular, the force 100 urges the panel 26 in movement relative to the remainder of the helmet assembly 10. As the panel 26 moves, the shafts 44 of the assembled rivets 38 are brought into bearing contact with the webs 90 which define the selected aligned openings 74a,82a. As the side panel 26 moves, the rivets 38 are forced against the webs 90, resulting in their deformation, as for example is shown in FIGS. 4b and 5b and the resulting relocation of each rivet 38 into a position aligned in a next adjacent opening 74b,82b as shown in FIG. 4b. It is to be appreciated that if a sufficient impact force 100 occurs, the portions 26,28 continue in relative movement, with the rivets 38 continuing to bear against and deform the webs 90 of adjacent openings 74,82. As such, the webs 90, in response to the impact force 100, sequentially deform in the direction of the applied impact force 100 thereby absorbing and dissipating the impact force 100 and permitting limited relative movement of the panel 26 relative to the panel 28.
It is to be appreciated that the presence of smaller peripheral openings 76,84 are provided as an added safety feature. In particular, the use of smaller diameter openings 76,84 which have a diameter smaller than the shaft 44 of the assembled rivets 38 advantageously prevent the panels 26 and 28, and 28 and 30 from being connected whereby the application of an impact force 100 would not be absorbed by a deformable web 90.
Although FIG. 3 illustrates the aperture arrays 72,80 as including a series of larger central openings 74,82 surrounded by a number of smaller diameter openings 76,84, respectively, the invention is not so limited. If desired, the smaller diameter openings 76,84 may be provided only about a portion of the openings 74,82, as for example, aligned in the direction of likely impact forces, or for that matter they may be omitted in their entirety.
It is to be appreciated that the construction of the helmet assembly 10 permits the shell 14 to be formed with comparatively thinner profile, while still dissipating impact forces 100. As such, the helmet assembly 10 may be closer fitted to the actual dimension of a user's head, and minimizes the likelihood that the wearer could suffer neck or soft tissue injuries which are associated with conventional helmet constructions.
Although FIGS. 1 to 5 illustrate the central panel 28 of the shell 14 as having a series of aperture arrays 80a–d formed along each edge portion 66 thereof, the invention is not so limited. FIG. 6 illustrates a partial perspective exploded view of a helmet assembly 10 in accordance with a further embodiment of the invention wherein like reference numerals illustrate like components. In FIG. 6, the longitudinal sides 66 of central panel 28 are provided with a series of single apertures 94a,94b,94c,94d in each tab portion 70a,70b,70c,70d, respectively. The apertures 94a–d have a size corresponding to the larger central openings 74 of the arrays 72a–d so as to permit insertion of a rivet 38 shaft 44 through the aperture 94 when aligned with a corresponding central opening 74 to couple the panels 26,28 and 28,30.
It is to be appreciated that with the construction of helmet assembly 10 shown in FIG. 6, the application of an impact force upon one of the panels 26,28 or 28,30 results in their relative sliding movement and the deformation of only the webs 90 which define the openings 74,76.
Although FIGS. 1 to 6 describe the right and left side panels 26,30 of the helmet assembly 10 as having a double wall 50a,50b construction, the invention is not so limited. It is to be appreciated that if desired, the central panel 28 could alternately be provided with a double wall construction, or for that matter only panels 26,28,30 having a single wall construction could be used.
Although FIGS. 1 to 6 illustrate the helmet construction 10 as including panels 26 and 30 which include arrays 72a–d of central opening 74 surrounded by smaller peripheral opening 76, the invention is not so limited. Reference may be had to FIG. 7 which shows a helmet construction 10 in which like reference numerals are used to identify like components.
In FIG. 7, the panels 26,30 are formed with a series of projections 62a–d which have a shark-tooth profile. A line of openings 74 extends along each projection to form each respective array 72a,72b,72c,72d. The openings 74 are oriented in a longitudinal line which is general parallel to the direction of typical impact forces and which is approximately inclined at an angle of 45° towards the central longitudinal axis A–A1 (see FIG. 2) of the helmet.
FIG. 8 shows best the fastener 138 used to secure the panels 26,30 to the central panel 28. The fastener 138 is formed from a semi-rigid plastic or rubber material so as to permit partial elastic deformation upon impact forces on the helmet construction 10 which do not exceed a critical load.
The fastener includes an elongated cylindrical central shaft 140, as well as an enlarged fastener head 142 and an enlarged diameter base 144. It is elongated and has a length selected to permit its insertion through the opening 74 formed in the panels 26,30 to secure the panels 26,28 and 30,28 in the identical manner as the rivet 38. Optionally, the fastener head 42 may be provided with a tapered forward surface 146 which facilitates its deformation and insertion through the aperture hole 74, enabling the fastener 138 to be positioned in a press-fit manner.
The formation of the fastener 138 from a material which permits partial elastic deformation advantageously acts to absorb impact forces. Furthermore, where an impact force does not exceed a predetermined threshold, the elastic deformation of the fastener 138 may function to provide sufficient impact absorbing forces without leading to the failure deformation of the webs 90.
Although FIGS. 3 and 8 describe the use of rivets 38 and deformable fasteners 138 as being used to secure the panels 26,28 and 30,28 together, other fastener constructions remain possible and will now become apparent.
Although the preferred embodiment describes the helmet construction 10 as a bicycle helmet, the invention is not so limited. It is to be appreciated that the helmet construction 10 of the present invention could be modified for almost any sports or non-sports application where a protective head covering could be required. Applications for the helmet construction 10 include, without restriction, its use as a horseback riding helmet, as a hard hat or construction helmet, football helmet, skateboard or snowboard helmet, a motorcycle or race car driver helmet, an army helmet for use in military applications and the like.
While the preferred embodiment describes and illustrates a rivet 38 used in the interconnection of the side panels 26,30 to the central panel 26, the invention is not so limited. If desired, other types of connectors including pins, screws and/or slot and tab connectors could also be used.
Although the detailed description describes and illustrates various preferred embodiments, the invention is not so limited. Many modifications will now occur to persons skilled in the art. For a definition of the invention, reference may be had to the appended claims.

## Claims

1. A helmet for protecting a user's head from impact forces, said helmet comprising,
a generally dome shaped shell, said shell being formed from a rigid or semi-rigid material and sized and contoured to cover a surface of said user's head to be protected, said shell including a first portion and a second portion,
a plurality of apertures formed through a region of said first portion,
said second portion including at least one locating opening formed therethrough and positioned to align with a selected one of said apertures when part of said second portion is located substantially in overlying juxtaposition with said first portion, and
a fastener sized for insertion through said opening and said selected one of said plurality of apertures to couple the first portion to the second portion,
said apertures being delineated from a next immediately adjacent aperture by a web member, said web member having a thickness selected to deform upon the application of a predetermined minimum force to at least one of said first portion and said second portion, and whereby the deformation of a web enables relative movement of the fastener from the selected one of said apertures into a next adjacent aperture and the limited movement of said first portion relative to said second portion.

2. The helmet of claim 1 wherein said peripheral edge region of the first portion is characterized by a double wall construction comprising a pair of spaced apart shell walls defining an interior area therebetween, the part of the second portion being at least partially disposed in said interior area.

3. The helmet of claim 1 wherein said first portion comprises a central portion of said helmet, said central portion being elongated in a longitudinal direction,
said second portion comprises a first longitudinal side portion of said helmet and said shell further comprises a second other longitudinal side portion having a substantially mirror construction to said first longitudinal side portion.

4. The helmet of claim 1 wherein said shell has a radial diameter which is selected not more than about two inches larger than the radial diameter of said user's head.

5. The helmet of claim 1 wherein said first portion and said second portion are each integrally formed from fibreglass or plastic.

6. The helmet of claim 1 wherein said fastener is selected from the group consisting of a removable screw, a permanent screw, a removable pin and a permanent pin.

7. The helmet of claim 2 wherein said first portion comprises a central portion of said helmet, said central portion being elongated in a longitudinal direction,
said second portion comprises a first longitudinal side portion of said helmet and said shell further comprises a second other longitudinal side portion having a substantially mirror construction to said first longitudinal side portion.

8. The helmet of claim 1 further including impact absorbing cushioning secured to an inner surface of said shell, said cushioning being resiliently compressible so as to compress with any movement of said first portion relative to said second portion.

9. The helmet of claim 1 wherein said helmet is selected from the group consisting of a hard hat and a military helmet.

10. A protective head covering for protecting a user's head comprising a generally rigid shell, the shell including a central portion and at least one side portion,
the central portion being elongated in a forward longitudinal direction and contoured so as to substantially cover the upper front and rear portions of said user's head, and
first one of said side portions being sized to cover a respective side of said user's head and having an edge portion positioned in overlying juxtaposition with a respective longitudinal edge region of said central portion,
a first array of a plurality of apertures being formed through the peripheral region of the first said side portion and a first longitudinal edge portion of the central portion and at least one locating opening formed through the other of the edge portion of the first said side panel and said first longitudinal edge region at a location selected to enable the alignment of the at least one opening with a selected one of said apertures,
at least one coupling member for insertion in an opening and said selected one of said apertures aligned therewith to couple said first said side portion to said central portion,
each of the apertures in said first array being separated from a next adjacent aperture by a web member having a thickness selected whereby the application of a predetermined minimum force to one of said first side portion and the central portion results in the limited movement of the central portion relative to said first side portion, and the movement of the coupling member in the direction of impact forces against the web member which defines the selected aperture so as to deform the web member and move into at least one next adjacent aperture.

11. The head covering as claimed in claim 10 wherein the plurality of apertures is sized to permit adjustment in the positioning of the first side portion relative to the central portion by varying the realigning of the at least one locating opening with different apertures.

12. The head covering of claim 11 wherein said array of apertures is provided through said first side portion.

13. The head covering of claim 10 wherein said shell has a radial diameter which is selected not greater than about four inches larger than a radial diameter of said user's head.

14. The bead covering of claim 10 comprising a second one of said side portions, each of said first and second side portions including
an inner panel wall,
an outer panel wall, and
a bight joining said inner and outer walls, whereby said inner and outer walls and said bight define an interior cavity open to a proximal edge, and wherein a respective longitudinal edge region of said central portion is interfitted between said inner and outer walls so as to extend at least partially within said cavity of each of said first and second side portions, respectively.

15. The head covering as claimed in claim 14 further including a plurality of longitudinal ventilation apertures formed through said shell.

16. The head covering as claimed in claim 10 wherein said coupling members are selected from the group consisting of rivets, pins and screw-type fasteners.

17. A helmet for protecting a user's head from frontal and side impacts, said helmet comprising,
a generally dome shaped shell, said shell sized and contoured to substantially cover said user's head, and including three discrete interconnected portions,
a first one of said portions comprising a central member elongated longitudinally so as to extend across front and rear portions of said user's head,
said remaining portions comprising first and second side members for overlying a respective side portion of said user's head,
a peripheral edge portion of said first side member provided in overlying juxtaposition with a first longitudinal side portion of said central member,
a peripheral edge portion of said second side member provided in overlying juxtaposition with a second other longitudinal side portion of said central member,
at least one of the first longitudinal side portion and said first side member including a first array of a plurality apertures formed therethrough,
the other one of said first longitudinal side portion and said first side member including a locating opening positioned so as to align with a selected one of said plurality of apertures in said first array, and
at least one of the second longitudinal side portions and the second side member including a second array of a plurality of apertures formed therethrough,
the other of said second longitudinal side portion and said second side member including a locating opening positioned so as to align with a selected one of said plurality of apertures in said second array,
a plurality of fasteners sized for insertion through each of said openings and said selected apertures aligned therewith to couple the first and second side members to the central member,
wherein the plurality of apertures of each of said first and second arrays are delineated from a next immediately adjacent aperture by a web member having a lateral thickness selected to deform upon the application of a predetermined minimum force, and whereby the application of said predetermined minimum force by said fastener deforms said web member and enables both relative sliding movement of the fastener into a next adjacent aperture and the limited relative movement of the interconnected portions.

18. The helmet of claim 17 wherein said peripheral edge portions of each of said first and second side members are characterized by a double wall construction comprising a pair of spaced apart walls defining an interior area therebetween,
a part of said first longitudinal side portion being at least partially disposed in the interior area of the peripheral edge portion of said first side member,
a part of said second longitudinal side portion being at least partially disposed in the interior area of the peripheral edge portion of said second side member.

19. The helmet of claim 17 wherein said shell has a radial diameter which is selected not greater than about four inches larger than the radial diameter of said user's head.

20. The helmet of claim 17 wherein said helmet comprises a hard hat.