The present invention relates to a protective helmet, for example a bicycle helmet, which comprises a outer shell of relatively hard material, an inner shell, fixedly secured interiorly in the outer shell and manufactured from an energy-absorbing and, in comparison with the material of the outer shell, a considerably softer material, as well as a belt set for securing the helmet on the user's head.

The present invention also relates to a method of manufacturing an outer shell for a protective helmet, for example a bicycle helmet.

Bicycle helmets are known in numerous various designs and constructions and, in recent times, it has become increasingly common that bicycles helmets have a relatively hard outer shell and, in relation thereto, a considerably softer inner shell of energy-absorbing material. In this instance, the purpose of the outer shell is to distribute the load against a relatively large surface area of the inner shell, to prevent the helmet from breaking into small pieces if, in powerful impact, the inner shell were to crack, and finally to prevent sharp objects from penetrating right through the helmet.

For the outer shell to have its intended function, it is vital that it covers the greater part of the outer surface of the inner shell. In such instance, problems arise in that the outer contour of the helmet is, as a rule, undercut in such a manner that, for example, a neck portion of the helmet is arched inwards and downwards in under the neck of the wearer's head In a corresponding manner, the front side portions of the helmet may converge on the outside in a downward direction.
   An outer shell for a bicycle helmet with this configuration is difficult to manufacture, since the outer shell will not have the requisite release capability in the tool in which it is manufactured. The alternative will therefore be an extremely complex and expensive tool for manufacturing the outer shell.

The present invention has for its object to design the protective helmet intimated by way of introduction such that the drawback inherent in the prior art technology are obviated. In particular, the present invention has for its object to form the protective helmet such that the outer shell may be manufactured in a simple and economical tool even though its final form is complicated and includes undercut features.

The present invention also has for its object to realise a method of manufacturing the outer shell.

The objects forming the basis of the present invention will be attained in respect of the protective helmet if this is characterized in that the outer shell has a number of sections where closely adjacent sections are interconnected to one another via connecting portions.

The objects forming the basis of the present invention will be attained in respect of the method if this is characterized in that the outer shell, on manufacture, is given a number of mutually contiguous sections.

Further advantages will be attained according to the present invention if the protective helmet is given one or more of the characterizing features as set forth in appended Claims 2 to 11 and if the method is given one or more of the characterizing features as set forth in appended Claims 12 and 14.

The present invention will now be described in greater detail hereinbelow, with particular reference to the accompanying Drawings. In the accompanying Drawings:

Fig. 1

is a straight side elevation of a protective helmet according to the present invention, and

Fig. 2

is a partial cross section through the helmet, taken along the section marking A-A in Fig. 1.

The protective helmet, for example a bicycle helmet, shown in Fig. 1 has a helmet shell with an outer shell 1 and an inner shell 2. The outer shell is manufactured from a relatively hard but nevertheless slightly flexible material, for example a plastic material. On the other hand, the inner shell 2 is manufactured from an energy-absorbing material which is considerably softer than the material in the outer shell. As examples of materials in the inner shell, mention might be made of various types of cellular plastic. Such materials display poor mechanical strength and readily crack in the event of, for example, impact loading.

The outer shell 1 is divided into a number of mutually contiguous sections, in the embodiment shown on the Drawings, an upper head section 3, a neck section 4 and two side sections 5. The side sections are located on each side of the helmet at a front, lower side portion thereof, approximately in the region of the temples of the wearer. Closely adjacent sections are interconnected to one another by means of connecting portions 6 and 7 which are somewhat flexible. In the final form of the helmet, closely adjacent sections have narrow, slot or groove-shaped interspaces 8 and 9.

The term and concept of undercutting will be employed below and can, in this context, be illustrated in Fig. 2 in that, in the finished state of the helmet, the distance between the lower edge of the side section 5 to the centre line 10 of the helmet is less than the distance between the upper edge of the side section 5 and the centre line 10.

Manufacture of the helmet in the illustrated embodiment may be put into effect without difficulty despite the fact that the outer shell 1 is undercut. This is because, on removal of the outer shell 1 from the tool in which it is manufactured, the undercut sections 4 and 5 will be pivoted away by flexing the connecting portions 7 and 6 respectively. However, this requires that the female part of the tool is divisible, since otherwise neither the male part of the tool nor the outer shell would be capable of being removed.

However, manufacture of the outer shell takes place in a form deviating from the final form, in which both of the side sections 5 are directed out from one another so that the above-mentioned undercuts do not occur. As a result, the requirement of a divisible female part in the tool is eliminated. Correspondingly, the neck section 4 is manufactured in a form deviating from its final form in which the neck section is directed outwards, i.e. rearwards, from the interior of the outer shell. As regards the degree of outward inclination of the side sections 5 and the neck section 4, it is sufficient if this is high enough for the undercutting of the outer shell 1 to be eliminated. However, it is suitable to have a greater outward inclination such that the insides of the side and neck sections are turned to face downwards or even partly outwards. This latter alternative implies that a pivot <90°, suitably in the range of between 120° and 170° is employed to cause the side and neck sections to assume their final positions in the outer shell. Such a pivoting takes place with the connecting portions 6 and 7 as joint portions.

When the insides of the side and neck portions 5 and 4 are turned to face outwards in the manufacturing process, it is also possible to apply to them (possibly manufacture in one piece with them) e.g. anchorage fittings for a belt set which the protective helmet is to carry in its finished state.

After the manufacture of the outer shell, the sections are brought to their final positions which, in the embodiment shown on the Drawings, entails that the side sections 5 are pivoted or bent towards one another by bending of the connecting portions 6, and that the neck section 4 is bent in a clockwise direction by bending of the connecting portion 7. This applies in both alternatives, since residual deformations often remain in the connecting portions. They should be manufactured in a divisible tool in positions which coincide with or approximate the final positions.

In the foregoing, the outer shell has been described as manufactured in one piece. Possibly, practical applications are conceivable in which the outer shell is manufactured in two or more parts, which may then individually be sectionally divided.

Further, the outer shell may be given a different sectional division than that described above. For example, solutions are conceivable in which the neck section 4 is divided into two rear, lower side sections. Possibly, solutions are also conceivable in which the upper head section is divided into a front section and a rear section.

Further modifications of the present invention are possible without departing from the scope of the appended Claims.