Protective helmet The present invention relates to a protective helmet comprising an outer shell, an inner shell and a material disposed between the outer and the inner shells which provides a shock-absorbing effect. The present invention further relates to a protective helmet comprising an outer and an inner shell which are connected by straps disposed between the shells. The present invention further comprises a shock-absorbing system on the inside of the inner shell consisting of cross bands which substantially absorb percussive energy and distribute it over the user's head. The shock-absorbing system with cross bands on the inside of the inner shell may further be used in connection with any other helmet regardless of whether the helmet consists of an outer and inner shell. The helmet is specially intended for servicemen in the field of fire-fighting and the police, as well as rescue teams, and design and choice of material will further contribute towards providing protection against shocks, impact, heat, etc. Furthermore, according to the invention the helmet can be provided with bodies which are adjusted relative to the user's head size and further designed in such a manner that the helmet satisfis a user's requirements for comfort and safety.

Amongst the previously known helmet solutions we refer to Norwegian patent 140407 which concerns a band device for helmets consisting of a band extending round the user's head, with a substantially x-shaped band unit placed over the head. Moreover, in US patent 5,517,691 there is described a helmet with an internally arranged shock-absorbing lining. Internally in the shock-absorbing lining there is further arranged a strap system substantially similar to the system which is described in the Norwegian patent, where a plurality of bands extend across the user's head to a band or the like extending round the user's head substantially along the helmet's lower edge.

The length of the bands may further be adjusted, thereby adapting the size of the helmet to the individual user's head shape and size.

The prior art solutions, and particularly the solution which is presented in the above-mentioned American patent 5,517,691 describe a solution in which mainly foam materials which are shock-absorbing are employed. The material forms an inner lining and on the underside has no surface against which the foam can abut in order to absorb the forces to which a helmet may be exposed. Thus in the event of an externally applied impact a helmet of the

previously known type will abut against the user's head, whereupon it will be deformed by shock absorption against the user's head. In those cases where the user's head abuts against a strap system provided on the inside of the lining, the strap system together with the lining's shock-absorbing ability will jointly represent the helmet's shock-absorbing effect.

As an improvement compared to the solutions which are mentioned above, and as a solution to the problems with which the known technical solutions are encumbered, in the present invention a helmet has been developed which on account of its constructive features provides substantially better shock- absorbing characteristics. It is an object of the present invention to provide a helmet which is developed from a light material in order to afford the user both comfort and security, since for a user there is a risk of neck damage amongst other things if the weight of the helmet is substantial relative to the weight of the user's head. If the total weight of helmet and head is high, the user has to strain his neck in order to keep helmet and head in balance, and if the body is exposed to a sudden movement the weight of the helmet and the head may damage the neck and the upper part of the back. It is a further object of the present invention to provide a helmet which is thermally insulating, e. g. for use in case of fire and in other areas with high temperature in order to protect the user's head against raised temperature.

Moreover, the helmet's shock-absorbing material will be almost unaffected by temperatures within the range of application, for example between-30 and +280 degrees Celsius. It is also an object of the present invention to provide a helmet whose size can very easily be adapted and whose design can offer adequate protection at the side and in the neck, while the helmet's constructive features can be adapted to different designs for special purposes.

The helmet may be used by different occupational groups exposed to the risk of impact against the head and the helmet must be capable at all times of satisfying the existing requirements for shock-absorbing ability which apply for general approval of such helmets for work purposes.

It is a further object of the present invention to provide a helmet which, when it is exposed to impact, is not deformed to such an extent that it no longer offers protection, which, for example, might be the case if the helmet, as disclosed in the above-mentioned US patent no. 5,517,691, is lined with a foam material which is elastic which is permanently deformed after impact.

The helmet should therefore be designed with a material or a composition of materials which, when exposed to stress, move to the greatest possible extent within the material's elastic range without assuming a permanent deformation.

The present invention thereby relates to a helmet consisting of an inner shell and an outer shell and disposed between the outer and inner shells a material which has shock-absorbing properties and which after an impact assumes to the least possible extent a permanent deformation while at the same time the material is light and thermally insulating. A suitable material which is employed in a preferred embodiment of a helmet according to the present invention is cork, especially of good quality such as primary cork. The material may be substantially cylindrical or globular in shape and if the shape is closer to oval, the standing oval shape should be arranged with the narrow side against the user's head, so that the material expands substantially in a direction across the user's head. If the material is substantially globular or cylindrical in shape, the pieces of material may be arranged in pyramidal or triangular groupings which permit lateral expansion and transfer force between the pieces of material.

Furthermore, in the area between the outer and inner shells the helmet in the present invention may be provided with a strap system which connects the outer and inner shells. Moreover, on the underside of the inner shell there may be provided a number of cross bands which extend chordially over the interior of the inner shell in such a manner that each band crosses each of the remaining bands at different locations. The bands are further attached to the inner shell in such a manner that the length of the band is optimally utilised in order to absorb impact, i. e. the force is distributed over relatively long bands and thus has to move a long way with related energy loss through the band's elasticity. The invention further relates to a system for size adaptation consisting of two halves arranged on each longitudinal side of the inner side of the inner shell. The two halves are slidably attached by friction or the like to the inner shell at the front of the helmet while the two halves at the rear of the helmet are connected to one or more elastic bands. In a preferred embodiment the two halves at the rear of the helmet assume a wider form which may represent a kind of"neck support"for the user. The elasticity in the connection between the halves adjusts the size according to what the user has on his head under the helmet and compensates for change in size as a

result of a user wearing a protective hood, smoke mask, safety suit or the like. The adaptation of size is also performed by moving the front parts of the two halves in the helmet's longitudinal direction.

Alternatively, the front part of the two halves can be attached to one of a plurality of studs, rivets or the like provided in the longitudinal direction.

A helmet according to the present invention can be designed with an inner and outer shell which are only connected by the said straps. The helmet can be designed with an outer and inner shell between which shells there is provided a shock-absorbing material, or the helmet can be designed with both the shock-absorbing material and the provision of straps. The choice of shock-absorbing design, either by using straps, shock-absorbing material or both is determined by financial considerations, as well as by an assessment of the area of application for a helmet and evaluation of the qualitative requirements which must be satisfied by the helmet for official approval.

Furthermore, the shock-absorbing system with cross bands as described above according to the invention may be provided on the inside of the inner shell in order to substantially absorb percussive energy and distribute it over the user's head. This can be employed together with a helmet according to the present invention consisting of an outer and an inner shell with shock- absorbing material and/or shock-absorbing straps disposed therebetween. The system with cross bands can further be employed with any other helmet, including a helmet with only one shell.

A helmet according to the present invention consisting of an outer and an inner shell with shock-absorbing material disposed therebetween is designed as indicated in the introductory part of independent claim 1, with characteristic features as indicated in the characterising part of the independent claim 1. Further embodiments of the helmet according to independent claim 1 are specified in the subsequent dependent claims. A helmet according to the present invention consisting of an outer and an inner shell, which straps provided therebetween, is specified in the introductory part of claim 7, with characteristic features as indicated in the characterising part of independent claim 7. A helmet according to the present invention consisting of an outer and an inner shell, with straps and shock-absorbing material disposed therebetween is indicated in the introductory part of claim

8 with characteristic features as indicated in the characterising part of independent claim 8. Further embodiments of the helmet according to claim 8 are indicated in the subsequent dependent claims. A helmet according to the present invention with a shock-absorbing system on the inside of the inner shell consisting of cross bands is indicated in the introductory part of claim 14 with characteristic features as indicated in the characterising part of independent claim 14. Further embodiments of the helmet according to claim 14 are indicated in the subsequent dependent claims. A helmet according to the present invention with a size-adjustment system consisting of two halves connected by elastic bands is indicated in the introductory part of claim 17 with characteristic features as indicated in the characterising part of independent claim 17.

In a preferred embodiment of the invention the helmet consisting of an outer and an inner shell with therebetween disposed shock-absorbing material in the form of substantially cylindrical pieces of cork which are substantially free in their relative movement and are thereby free to expand in all directions. Alternatively, the shock-absorbing material may be globular or in the form of rods oriented in a standing position between the inner and the outer shells. Furthermore, the helmet in the preferred embodiment is provided with a shock-absorbing system with cross bands on the inside of the inner shell and the helmet is provided with a system for size adjustment as stated above.

Further features of the invention will be apparent in the following description and in the patent claims. The invention will now be described with reference to the attached drawings, in which: fig. 1 is a section viewed from the front of an embodiment of a helmet with an inner and an outer shell and a shock-absorbing material disposed therebetween; fig. 2 is a section viewed from the side of a helmet as in fig. 1 where a shock- absorbing material is disposed between the outer and the inner shells; fig. 3 is a section viewed from the side of an embodiment of a helmet as in figures 1 and 2 where a shock-absorbing cross band system is provided on the inside of the inner shell;

fig. 4 illustrates an embodiment of elastic attachment of the cross bands to the inner shell; fig. 5 illustrates an embodiment of the attachment with straps between the outer and the inner shells; fig. 6 is a section viewed from above illustrating how the cross bands in an embodiment as illustrated in fig. 3 are disposed; fig. 7 is a section viewed from behind of an embodiment of a system for size regulation according to the invention.

In fig. 1 there is illustrated a section viewed from in front of a helmet according to the present invention where an outer shell 1 and an inner shell 2 are arranged with shock-absorbing material 4 placed between the shells. The outer shell 1 is preferably of a rigid, impact-and heat-resistant material such as epoxy glass, and the inner shell 2 may be of a rigid construction, but in a preferred embodiment is of a softer material such as polyurethane. In the area between the outer shell 1 and the inner shell 2 there is further disposed a shock-absorbing material 4 which in the event of an impact against the outer shell reduces the force transferred to the inner shell 2 and on to the user's head. The shock-absorbing material 4 preferably has a low specific weight and low E-module, preferably consisting of several independent elements which have the possibility of expansion in a direction which points to the least possible extent towards the user's head. In figures 1 and 2 the elements are grouped in pyramidal or triangular groups which permit lateral expansion and provide the transfer of force between the elements. In a preferred embodiment the shock-absorbing material 4 as illustrated in fig. 1 is substantially cylindrical cork elements arranged in pyramidal groupings which are adapted to the space between the outer shell 1 and the inner shell 2. The cylindrical elements may be arranged in several layers located on the outside of one another and in figs. 1 and 2 two layers are substantially illustrated. In a preferred embodiment the shock-absorbing, substantially cylindrical elements are not attached to one another to any considerable extent, thus enabling them to expand freely in the event of impact against the outer shell 1.

The direction of orientation of the cylindrical, shock-absorbing elements may be varied through the space between the outer shell 1 and the inner shell 2,

and in fig. 2 in a section viewed from the side it is illustrated how the shock- absorbing elements round the upper part of the user's head are oriented in the direction of the head from the back of the head towards the face, while the shock-absorbing elements at the rear of the head are oriented across the head.

The orientation of the shock-absorbing elements may be varied, however, and adapted to the space which is available between the outer shell and the inner shell. In a preferred embodiment as illustrated in figs. 1 and 2, the shock- absorbing material is cork or a cork-like material. In an alternative embodiment the space between the outer shell 1 and the inner shell 2 may be filled with balls or globular elements which are not interconnected, thus enabling them to expand freely in every direction.

In figure 3 there is illustrated an embodiment of a helmet according to the present invention with features similar to the helmet illustrated in figures 1 and 2. On the inside of the inner shell there is further provided a shock- absorbing system with cross bands 6 which extend chordially over the interior of the inner shell 2 and at a distance from the inside of the shell 2, in such a manner that each band 6 crosses and is nested to each of the remaining bands 6 in different locations 7, thereby achieving a dispersion and transfer of forces applied to the outer shell 1 to all the bands 6 at nodes 7. In figure 4 the bands 6 are shown attached to the inner shell 2 by means of elastic pads 8 of silicon rubber which are held in place by a disc 9 and the band 6 is locked by a locking pin 10.

Furthermore, in figure 5 as a part of the shock-absorbing system the outer shell 1 and the inner shell 2 are attached to each other by means of a number of elastic fixing straps 11 which are passed through bores in the two shells and locked under tension by means of tension release devices 12. The tension release device 12 on the inside of the inner shell 2 is embedded in this shell in an appropriate manner.

In fig. 6 in a section viewed from above there is further illustrated an embodiment of a helmet according to the present invention as in figure 3 where the cross bands 6 cross one another at locations 7. The bands are preferably of Aramide, extending chordially over the interior of the inner shell in such a manner that each band 6 crosses or is nested to each of the remaining bands at different locations 7, thereby achieving a dispersion and transfer of forces applied to the shell 2 to all the bands 6 at nodes 7 as

illustrated in figure 3. Two of the locations 6 in fig. 6 are located in the helmet's longitudinal symmetry plane, and the remaining locations are symmetrically arranged on both sides of the said symmetry plane.

The helmet according to the present invention is further provided with a size regulation system 3 which preferably consists of two rigid hoops 3 of composite material, whose reinforcing fibres are oriented in such a manner that the hoops have flexibility as well as torsional resistance. In fig. 7 each of the hoops 3 is attached to the inner shell 2 at its front portion. The attachment can be implemented with a rivet or the like, or the hoops 3 can be moved in slots in the shell 2 by friction or locking. The hoops 3 extend backwards along the inside of the inner shell for interconnection in the rear edge, in an end portion 13 which acts as a neck support, by means of one or more adjustable elastic straps 14. In this fashion a helmet according to the present invention can be easily adapted to a user's head shape and size regardless of other headgear and in an emergency situation a user can pick up any helmet whatever and adjust it easily at the front before adjusting the distance between the plates 13 by means of the two adjustable elastic straps 14.

Other embodiments which are obvious to a person skilled in the art fall within the scope of the protection according to the following patent claims.