A helmet

Abstract: When shock acts on a helmet which a driver of a motorcycle or the like wears, rotational component as well as advancing component of the shock can be absorbed effectively. In a helmet (10) with a shock absorbing liner (12) fitted on an inner side of a shell (11), a layer of elastic body (15) for absorbing shock having a component directed along an outer surface of the shell is provided between the shell (11) and the shock absorbing liner (12) or between an outer layer (13) of the shock absorbing liner (12) and an inner layer (14) of the shock absorbing liner (12).

Description: BACKGROUND OF THE INVENTION The present invention relates to a helmet which a driver of a vehicle such as a motorcycle or a racing car wears. Hitherto, a helmet as shown in Japanese Laid-Open Patent Publication Hei 6-240508 has been known. In this helmet, a reinforcement cloth made of a strengthening fiber is interposed between a shell and a shock absorbing liner fitted within the shell or between two layers of the shock absorbing liner and fixed thereto, in order to obtain improved shock absorbing performance without increasing thickness of the shell. Shock load acting on the helmet is classified roughly into a load in a direction toward a center of the helmet and a load in a tangential direction (rotational component) deviating from the center. In the customary helmet, both loads are absorbed by deformation of the liner or the like. A helmet according to the preamble of claim 1 is known from US-4,064,565. Here, a helmet is shown having an outer shell and a shock absorbing structure provided on the inner side of the shell. The shock absorbing structure is made up of an outer impact absorbing layer attached to an inner surface of the outer shell and an inner form fitting layer. Between the impact absorbing layer and the form fitting layer, there is provided a transfer layer formed of a substantially incompressible fluid or gel. This transfer layer operates to transmit a radially directed force uniformly throughout the transfer layer such that an impact force applied at one point to the outer shell is converted to a uniform pressure in the transfer layer. Therefore, in case of a radial shock the impact force applied to a person's head is reduced as compared to the impact applied locally to the outer shell of the helmet. A similar construction is known from DE-U-92 08 406. WO96/14768 discloses a helmet comprising an outer elastic membrane which is located outside an essentially rigid shell. The outer membrane is able to move relative to the shell. To facilitate this movement between the outer membrane and the shell, a lubricant (for instance a lubricant gel) may be used. SE-A- 9802228 describes a helmet having an outer shell and an inner impact absorbing shell, the outer shell being displaceable relative to the inner shell by means of at least one sliding layer arranged between the outer shell and the inner shell. In the edge region of the helmet, the outer shell and the inner shell are interconnected by means of connecting members, for absorbing energy on displacement of the outer shell on the inner shell. SUMMARY OF THE INVENTION It is the object of the present invention to propose a helmet capable of absorbing the rotational component of shock effectively. For this purpose, the present invention provides a helmet according to claim 1 or 2. The helmet has a shock absorbing liner fitted on the inner side of the shell, wherein the shock absorbing liner is split into an outer liner and an inner liner, and a layer of gel is provided between the outer liner and the inner liner for absorbing shock having a component directed along an outer surface of the shell. Since the head of the wearer and the shell are not fixed to each other, when shock force acts on the helmet from the outside, rotational acceleration, that is, an acceleration component directed along an outer surface of the shell is absorbed, as well as advancing acceleration, that is, an acceleration component directed perpendicularly to the outer surface of the shell. The split surface of the outer liner and the inner liner may be formed in a spherical surface or an aspherical surface. Since the layer of gel is provided along the split surface, the outer liner and the inner liner can slip relatively easily, so that degree of freedom in rotational direction becomes large and the rotational component of the shock force can be absorbed more effectively. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a vertical sectional view of a helmet not according to the present invention; Fig. 2 is a vertical sectional view of a helmet according to a first embodiment of the present invention; Fig. 3 is a vertical sectional view of a helmet according to a second embodiment of the present invention; Fig. 4 is a vertical sectional view showing a broken helmet according to the second embodiment; Fig. 5 is a sectional view showing a third embodiment of the present invention; and Fig. 6 is a sectional view showing a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Fig. 1 is a vertical sectional side view showing a conventional helmet. The helmet 20 has a shell 21 manufactured by injection molding of nylon and a shock absorbing liner 22 of styrene foam fitted and stuck on an inner side of the shell 21. The shock absorbing liner 22 is divided into an outer liner 23 and an inner liner 24 with a split surface extending along a spherical surface 26. In this embodiment, a layer of absorbent elastic body 25 is provided between the outer liner 23 and the inner liner 24 and stuck to the both shock absorbing liners 23, 24. As for the absorbent elastic body 25, gel is used, particularly an NP gel (registered trade marks) and foam gel can be used. This is the same with respect to other embodiments to be described below. Since a head of a wearer of the helmet is not fixed to the shell 21, when shock force acts on the helmet from the outside, a rotational component, that is, the component directed along the outer surface of the helmet is also absorbed, as well as an advancing component, that is, the component directed perpendicularly to the outer surface of the shell 21. In this embodiment, since the split surface between the outer liner 23 and the inner liner 24 is spherical surface and the layer of absorbent elastic body 25 is provided along the spherical surface, the outer liner 23 and the inner liner 24 can easily slip relatively and the degree of freedom in rotational direction becomes large so that the rotational component of the shock force can be absorbed easily. Fig. 2 is a vertical sectional side view showing a first embodiment of the present invention. The helmet 30 has a shell 31 manufactured by injection molding of polypropylene and a shock absorbing liner 32 of styrene foam fitted and stuck on an inner side of the shell 31. The shock absorbing liner 32 is split into two layers through a split surface extending along a spherical surface 36, and a layer of absorbent elastic body 35 is disposed between an outer liner 33 and an inner liner 34 and stuck thereto. In this embodiment, at the edge of the inner liner 34 is provided a flange 34c directing outward. The present embodiment has the same effect as the above-mentioned helmet 20. Moreover, when the outer liner 33 and the inner liner 34 rotate relatively to a limit, the flange 34c collides with an edge of the outer liner 33 to restrain an excessive rotation. Though the flange 34c is provided at the edge of the inner liner 34 directing outward, the flange may be provided at the edge of the outer liner 33 directing inward so as to collide with the edge of the inner liner 34. Fig. 3 is a vertical sectional side view showing a second embodiment of the present invention and Fig. 4 is a vertical sectional view showing a state of the helmet after shock is absorbed. In Fig. 3, the helmet 70 comprises a shell 71 and a shock absorbing liner 72 fitted and stuck on an inner side of the shell 71. The shock absorbing liner 72 is split into an outer liner 73 and an inner liner 74, and a layer of absorbent elastic body 75 is disposed between the outer liner 73 and the inner liner 74 and stuck to the outer liner 73 and the inner liner 74. In this embodiment, the split surfaces of the outer liner 73 and the inner liner 74 are not spherical surfaces. When shock force having rotational component acts on the helmet 70 from the outside to rotate the outer liner 73 and the inner liner 74 relatively, the layer of absorbent elastic body 75 is deformed so that a part thereof is compressed to collapse and another part is expanded to produce a cavity. Thus an excessive rotation is restrained. Fig. 5 is a sectional view showing a third embodiment intended to use the construction according to any of the first and second embodiments of the present invention. A layer of absorbent elastic body 85 is disposed between an outer liner 83 and an inner liner 84 and stuck to the both liners 83, 84. However, in this embodiment, a gel having air rooms 85d therein is used as the layer of absorbent elastic body 85. The air room 85d may be a bubble. According to this embodiment, air in the air room 85d improves cushion effect and contributes to reduce weight of the helmet. Fig. 6 is a sectional view showing a fourth embodiment intended to use the construction of the present invention. According to this embodiment, between an outer liner 93 and an inner liner 94 are disposed some layers of absorbent elastic body 95 so as to form a suitable number of spaces as air rooms 97. The layer of absorbent elastic body 95 is stuck to the outer liner 93 and the inner liner 94. This embodiment exhibits the same effects as those of the third embodiment. In the above-mentioned embodiments, it is also possible to partly connect inside of the liner with outside of the shell for ventilation, within a limit not departing from the above-mentioned effects. When shock acts on a helmet which a driver of a motorcycle or the like wears, a rotational component as well as an advancing component of the shock can be absorbed effectively. In a helmet with a shock absorbing liner fitted on an inner side of a shell, a layer of elastic body for absorbing shock having a component directed along an outer surface of the shell is provided between an outer layer of the shock absorbing liner and an inner layer of the shock absorbing liner.

Claims: A helmet having an outer shell (31), a shock absorbing liner (32) provided on the inner side of the shell said shock absorbing liner being made up of an outer liner (33) attached to the inner surface of the outer shell (31) and an inner liner (34), and elastic means (35) provided between said outer liner (33) and said inner liner (34), characterized in that said outer liner (33) and said inner liner (34) have therebetween a split surface extending along a spherical surface (36) and are capable of slipping relative to each other along said spherical split surface in response to a shock having a component directed along said split surface, said slipping movement being restrained against excessive rotation, one of said outer liner (33) and said inner liner (34) having at an edge thereof an abutment flange (34c) for preventing the other liner from rotationally slipping excessively relative to the one liner, and said elastic means (35) is a gel to allow relative slipping movement between said outer liner (33) and said inner liner (34) along said split surface and to absorb a shock having a component directed along the outer surface of said outer shell (31). A helmet having an outer shell (71), a shock absorbing liner (72) provided on the inner side of the shell, said shock absorbing liner being made up of an outer liner (73) attached to the inner surface of the outer shell (71) and an inner liner (74), and elastic means (75) provided between said outer liner (73) and said inner liner (74), characterized in that said outer liner (73) and said inner liner (74) have therebetween a split surface extending along an aspherical surface and are capable of slipping relative to each other along said aspherical split surface in response to a shock having a component directed along said split surface, said slipping movement being restrained against excessive rotation, said elastic means (75) is a gel to allow relative slipping movement between said outer liner (73) and said inner liner (74) along said split surface and to absorb a shock having a component directed along the outer surface of said outer shell (71). A helmet according to claim 1 or 2, characterized in that said gel is a foam gel. A helmet according to any of claims 1 to 3, characterized in that air bubbles (85d) are confined in the gel.

Inventors: ITOU TETSUYA, NAKAYAMA KENGO, ONO NAOTO, OSHIGAMO HIROAKI, ITOU, TETSUYA, NAKAYAMA, KENGO, ONO, NAOTO, OSHIGAMO, HIROAKI
Applicants: HONDA ACCESS KK, HONDA MOTOR CO LTD, HONDA GIKEN KOGYO KABUSHIKI KAISHA, KABUSHIKI KAISHA HONDA ACCESS
Application year: 2001
Main classification: A42B3
IPC codes: A42B3