AU668266B2

AU668266B2 - Helmet, particularly a bicycle crash helmet; and process for its manufacture

Info

Publication number: AU668266B2
Application number: AU55230/94A
Authority: AU
Inventors: Gerhard Sperber
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-02-25
Filing date: 1994-02-18
Publication date: 1996-04-26
Anticipated expiration: 2014-02-18
Also published as: CA2115695A1; EP0612483A1; EP0612483B1; ES2116392T3; JPH06280105A; ATE164292T1; CA2115695C; AU5523094A; DE59308311D1; DK0612483T3

Abstract

The present invention relates to a helmet, especially a plastic protective helmet for cyclists, and to a method of manufacturing it. To achieve the object of the invention, to provide a plastic helmet which can be produced at a considerably lower manufacturing cost, but with increased resistance to loading, it is proposed to manufacture the helmet in dual-wall (2, 3) construction from blow-moulded plastic. Furthermore, means are to be provided, which bring about a reinforcement of the walls (2, 3) of the helmet (1) relative to one another under compression loading, it being possible for these means to be implemented, preferably, in the form of openings (e.g. 30). <IMAGE>

Description

AUSTRALIA

Patents Act 0 8 fo 266 COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: e.

.9 9 o 4 9 9*9* 9*9* *9*9 *o 9 Name of Applicant: Gerhard Sperber Actual Inventor(s): Gerhard Sperber Address for Service: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: HELMET, PARTICULARLY A BICYCLE CRASH HELMET; AND PROCESS FOR ITS MANUFACTURE Our Ref 356790 POF Code: 43733/220793 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): ~e lp I_ I I_ The invention relates to a helmet, particularly a bicycle crash helmet of plastic. In this context it is known that the bicycle crash helmets are made from deep-drawn plastic or a foamed plastic. In both cases, manufacturing costs are extremely high and thus have a negative effect on the practical use of such bicycle crash helmets that are actually very desirable and necessary for safety reasons. Furthermore, bicycle crash helmets of deep-drawn plastic have the disadvantage that they are relatively heavy. Bicycle crash helmets of foamed plastic can only be foamed in certain colors. A complete disposal of the helmets also is not always ensured according to the present state of the art.

Another disadvanctage of known bicycle crash helmets is that they may be irreparably damaged (tears, breaks, etc.) during a fall, and the stability of the bicycle crash helmet is deteriorated. This makes it necessary to dispose of the bicycle crash helmets and replace them with new bicycle crash helmets.

In this context, there is also the danger that tears in the bicycle crash helmet consisting of foamed polystyrene are not immediately detected by the user, resulting in risks when the helet is used.

It is therefore considered desirable to create a helmet, particularly of plastic, that can be manufactured at lower manufacturing costs than prior art plastic helmets, but where the resistance to stresses, e.g. during a fall, are not 20 affected negatively.

S" According to an aspect of the present invention, there is provided a helmet for use as a bicycle crash helmet wherein the helmet is formed of plastic and is double-walled having an inside wall and an outside wall defining a chamber therebetween.

25 The double-wall construction combines the advantage of a high resistance 600 00:: to the forces that must be absorbed by the helmet during a fall and especially an absorption due to the enclosed chamber with the further advantage of the very S .0 0 low weight of this hclmet.

The above advantages are synergically supported by the preferred 30 characteristic of the double wall consisting of a blown plastic. On the one hand,

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this results in a significant reduction in manufacturing costs since the helmet can c be made in a single shaping process, and on the other hand, although a blown plastic is elastic, it has however a certain hardness and is therefore especially suitable e.g. for a bicycle crash helmet. Finally, the blown plastic may have a relatively thin wall thickness, something that significantly contributes to the desired reduction in weight. In contrast to foamed helmets of foamed polystyrene), the helmet according to the invention may easily be returned to its starting shape in the case of a lasting deformation, namely by heating the deformed point with hot water or a blow dryer, etc. Said dents then "snap" back to their original shape. In contrast to standard bicycle crash helmets of foamed polystyrene, damages in the new helmet are immediately visible and are unable to increase the user's risk of such a bicycle crash helmet. It is also possible that the helmet can be colored in any color the clients desire, something which so far was not possible when foamed polystyrene was used. It is even possible to add odorous substances to the plastic, thus increasing the marketing effect or sales of such helmets, e.g in the case of special helmets for children.

The helmet of this invention is preferably of a one-part construction. This i.as the advantage that the helmet shell can be manufactured in a single manufacturing step, so that it is no longer necessary to perform installation or S. adhesion steps. There is also no longer the risk that glued points come apart *i *0 Swhen the helmet is subjected to mechanical or thermal stresses.

20 The multi-shell construction of the helmet according to the invention offers the advantage that the hollow chamber--if so desired--can be filled or lined with special absorption material, something which may be of importance for certain applications or for a certain absorption material itself that cannot be injected or foamed in.

25 To increase the deformation resistance of the helmet or bicycle crash helmet according to the invention, means are preferably provided that cause a 0 reinforcement of the walls of the helmet under pressure stress and also when the 0 helmet is contorted. This double wall construction thus creates a helmet that completely fulfils the technical requirements regarding stability and in addition far 30 surpasses the properties of standard helmets (bicycle crash helmets) made e.g.

from foamed polystyrene.

The reinforcement offers the advantage that, if a user falls and the head protected by the helmet hits a hard object, road surface, etc., the invented helmet is able to absorb a greater impact energy than a helmet that has no reinforcements. With the latter, it may be the case that the two helmet walls touch each other at the impact point even in the case of a slight impact, and the impact energy still present acts on the head of the driver without prior absorption.

It is preferable that the reinforcement means includes at least one breakthrough. The break-through walls are closed in themselves, thus bringing about a connection between outside wall and inside wall of the helmet in the area of the break-through. The walls of the break-through result in a reinforcement of the helmet walls relative to each other and thus in an increased suitability for impact absorption. This design has the additional advantage that it offers the possibility of producing or at least preparing the break-throughs during the blowing process in a one-part helmet. It is desirable that the two walls are molded to each other in the area of the break-through and are then cut out, thus creating the corresponding break-throughs. In addition to the reinforcing effect, the breakthroughs have the added advantage that they ensure air circulation between the ;user's head and the helmet inside.

It is useful for this purpose that several break-throughs are provided and 20 that they are of elongate construction and oriented in the longitudinal direction of S• the helmet.

In at least one embodiment of the invention, the distance between the walls of the break-throughs seen in cross-section, decreases from the outside wall towards the inside wall at least over a part of the distance from outside wall 25 to inside wall. This has both manufacturing-technical advantages, and also causes a certain absorption behaviour inthe area of the break-throughs due to the walls that have been constructed so as to extend obliquely.

It is preferable to furthermore provide ribs at the outside and/or in in order to increase the rigidity of the helmet more.

30 Other measures that ira ly increase the rigidity of the helmet are describsli-m re-detail later. The various means for reinforcement of the helmet 4a Thus, according to a particularly preferred embodiment, this invention provides a bicycle helmet, comprising: a one-piece helmet body including a) a pair of concentrically spaced outer and inner helmet shells formed of plastic material; and b) means connecting said shells to form an unitary body, said shells containing openings, and said connecting means comprising an annular wall surrounding the respective opening, said annular wall having a generally double V-shaped cross sectional configuration and including successively axially converging and diverging wall portions in the direction from said outer shell to said inner shell.

It is preferable to furthermore provide ribs at the outside and/or inside walls in order to increase the rigidity of the helmet more.

Other measures that may desirably increase the rigidity of the helmet are 15 described in more detail later. The various means for reinforcement of the helmet a.e .a a e* a.* ae e e make it possible to easily fulfil the respective domestic and foreign legal regulations or standards.

It is possible that inside the hollow chamber formed by the two walls a certain distance may exist between facing walls, thus facilitating the manufacturing or the helmet using the blowing process It is also possible to foam out the chamber between the two walls with a suitable material, especially plastic, in order to reinforce or increase the absorption effect.

As an alternative, it is possible that the chamber, especially in the case of a two-part design of the helmet, is filled with particles of foamed plastic as an additional shock absorber. This makes it possible to manufacture the entire helmet from recyclable material.

To increase the shock absorption, an alternative design of the invention provides that the entire hollow chamber is subject to an overpressure.

Because of the double wall construction of the invented helmet, the hardness and/or wall thickness of the plastic can be adapted to the helmet dimensions and/or the desired impact resistance.

Suitable materials for manufacturing the invented helmet include recyclable plastics such as polyeth:ylene, polypropylene copolymer, polystyrene copolymer, S 20 acryl-butadiene-styrene, ABS, polyamide or polycarbonate.

Due to the manufacturing of the helmet using the blowing process, it is o o possible that the plastic material itself contains luminescent, fluorescent dyes or color pigments. In prior art foamed polystyrene helmets, this has to be realised with a foil that had to be additionally applied to the foamed polystyrene helmet.

25 'ihe same is true for the use of plastic material which in the case of the invention even may be equipped with odorous substances, so that especially in the case of children's bicycle crash helmets a special "marketing gag" is made possible.

t o order to avoid injuries to the user through an impact of the helmet.onto the nose edge during a fall, a preferred embodiment of the helmet of this 30 invention provides that the front side of the helmet facing the face of the user has a recess in the center, thus reducing the edge effect of the front side of the d helmet.

llpa~ I T- It is preferable that in the area of the break-throughs fan wheels are provided that ensure an increased aeration of the break-throughs. The fan wheels can be driven both by the driving wind or even by a solar cell that is located e.g.

at the outside of the outside wall of the helmet.

Further preferred embodiments of the invention provide especially designed air outlet openings for influencing the absorption behaviour of the helmet.

According to another aspect of this invention, there is provided a helmet for use as a motorcycle helmet wherein it includes a helmet as described above as a basic structure and wherein the basic structure carries at its outside an additional helmet shell in rigid connection.

Standard crash helmets of foamed polystyrene are thus replaced with the new basic structure of plastic and with double wall construction.

According to a further aspect of this invention there is provided a process for manufacturing a helmet as described above wherein the helmet is blown inside a mold of at least one plastic tube in such a way that the tube is shaped inside a hollow chamber of the form into a double wall forming the helmet.

:This makes it possible to manufacture such a helmet in an especially j simple manner, whereby simultaneously all advantages of the plastic used for this 20 purpose can be transferred to the helmet production.

It is particularly advantageous that with the blowing process it is goe' simultaneously possible to also incorporate the reinforcements in the form of wall areas into the helmet, whereby said areas are in contact with each other and are then cut out, thus creating break-throughs that both reinforce and aerate the 25 helmet.

;In order to better understand the present invention, preferred e bodiments are hereafter described with reference to the accompan rawings, in which 0 9 are shown: Fig. 1 a lateral view of a bicyA crash helmet according to the invention; 30 Fig. 2 a sectio anig line I-I in Fig. 1; Fi a section through a mold with inserted tube to be blown into a uble wall bicycle crash helmet; 1 I-1 6a Throughout the description and claims of this specification the word "comprise" and variations of that word, such as "comprises" or "comprising", are not intended to exclude other additives or components or integers.

In order to better understand the present invention, preferred embodiments are hereafter described with reference to the accompanying drawings, in which are shown: Fig. 1 a lateral view of a bicycle crash helmet according to the invention; Fig. 2 a section along line 1-1 in Fig. 1; Fig. 3 a section through a mold with inserted tube to be blown into a double wall bicycle crash helmet; *o

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DG Document8 -e Fig. 4 a lateral view of another design of the bicycle crash helmet according to the invention; Fig. 5 a section along line 111-111 in Fig. 4; Fig. 6 a top view of the front part of the helmet according to the bicycle crash helmet in Fig. 4; Fig. 7-10 sections of possible reinforcements of the helmet walls; Fig. 11 section of the helmet walls with additional plastic layer; Fig. 12 a lateral view of another design of the bicycle crash helmet according to the invention.

Fig. 13 a section according to line IV-IV in Fig. 12 with another possible design for producing a reinforcement; Fig. 14-16 partial sections through the helmet, with different possible realisations of the reinforcement at a larger scale; Fig. 17 another design of the invented helmet that has fan wheels in the area of the break-throughs (cross-section view of the respective partial area); and Fig. 18 a diagrammatic view of a motor cycle crash helmet using the helmet of the invention as a basic structure.

SThe helmet, here bicycle crash helmet 1 is--as shown in Fig. 2--doublewalled, it consists of an outside wall 2 and an inside wall 3 that in itself delimit S 20 a closed hollow chamber 4 on both sides. At their front faces 5, the walls 2, 3 merge into each other so as to seal the hollow chamber 4 there towards the S outside. The walls 2, 3 with their front faces 5 are thus a one-part element forming the bicycle crash helmet 1, consisting of an appropriate plastic, preferably polyethylene.

25 Standard absorption strips of foamed plastic or rubber and the standard o chin straps 7 can be attached to surface 3' of inside wall 3. For this purpose, openings (not shown) transcending both walls 2, 3 may be present, into which the •9 °moided parts 40 carrying the chin straps 7 are inserted, whereby a safe connection is realised by clamping, slot-spring connection, etc.

30 It is useful that the hollow chamber 4 is connected to outside air via small *see air passage openings. In addition or instead of these openings 8, it is also possible that openings 8' with a larger diameter are provided that are closed off Nr4' o with an overpressure valve, preferably a valve 9 attached to the outside. In the case of a shock, the impact force results in a pressure on both wall parts 2, 3 in the direction towards the hollow chamber 4. This is especially true for outside wall 2. This compresses the volume of the hollow chamber 4. To achieve a desired, elastic resilience of the crash helmet, it is advantageous that the air present in the hollow chamber 4 is able to escape through openings 8, 8' to the outside. Hereby a certain slowing of the air discharge may be found to be advantageous. In the case of the examples of openings 8, this is achieved by a correspondingly lower diameter of the openings, and in the example of openings 8' by a plastic or rubber flap that presses with its inherent elastic force from outside against opening 8', whereby this elastic force also can be overcome by the air that streams out.

The flap 9 is attached at the cutting line 10 of the outside of the helmet 1.

Other such arrangements are also feasible.

Fig. 3 shows a totally schematic illustration of the blowing of such a crash helmet using a mold 11 that has a recess 12 corresponding to the external dimensions of the crash helmet to be manufactured. Into this recess 12 or opening is inserted a tube 13 that is blown up via an air conduit 14 and is hardened in the desired manner using heat.

It is also important in this manufacturing process that attachment slots for

B

e, 20 the chin straps 7 can be advantageously incorporated into the blown plastic. They 0 B have a higher resistance to tearing than bicycle crash helmets manufactured from foamed plastic foamed polystyrene) or by deep-drawing.

It is particularly possible to use a recyclable plastic, e.g. polyethylene, polypropylene, copolymer, polystyrene copolymer, acryl-butadiene-styrene, ABS, 25 polyamide PET (polyethyleneterephthalate), or polycarbonate to manufacture the bicycle crash helmet. Wall thickness, elasticity, and hardness of the plastic can be adjusted according to the desired requirements.

e,.The hollow chamber between the two walls 2, 3 can be filled with a foamed plastic. This may be realised either by foaming or by filling in, small spheres of foamed plastic.

ABce Fig. 4 shows another design of the invented bicycle crash helmet with .break-throughs 30, 31 arranged at the top side that cause an increase in rigidity between the two walls 2, 3 during pressure stress and thus significantly improve the ability of the bicycle crash helmet 1 to absorb shock energy.

The individual break-throughs 30, 31 have side walls 34, 35 that connect the outside wall 2 to the inside wall 3, so that the remainip, hollow chamber 4 remains closed in itself.

Fig. 5 shows that the side walls, e.g. 34, extend towards each other over a partial area of the distance between outside to inside wall 2 or 3, and only diverge again in an inside area.

A rib 33 extending in arc-shape from the front to 'ds the back and having an additional stability-promoting effect is provided or ueac!t VJe of the bicycle crash helmet 1 for further reinforcement of the bicycle crash helmet 1. In addition to the effect that increases the rigidity, this ensures an especially good aeration of the head area of the user of such a bicycle crash helmet 1. Fig. 6 furthermore shows that the individual break-throughs, e.g. 30, 31, are disposed offset to each other, improving the rigidity profile of the bicycle crash helmet 1 yet more.

Fig. 6 also shows the laterally attached rib 33 for further increasing the rigidity. A ribbing (compare rib 34 in Fig. 5) of the inside wall 3 increases the rigidity also.

It is also possible to explain the realisation of breakthroughs 30, 31 with 20 reference to Fig. 6. The bicycle crash helmet 1 consists of two walls 2, 3 that--as 4.:9*9 already mentioned-are manufactured from a tube using the blowing process. After It.: the blowing process but prior to unmolding, the tube walls 2, 3 are pressed against each other over partial areas 22, 23, 24 so that they adhere to each other there. The areas 22, 23, or 24 that adhere to each other are then cut out along ,o0, 25 the cutting lines 10 (indicated by slash-dotted line).

The edges surrounding these areas 22, 23, or 24 are formed by the two parts of the walls 2, 3 that adhere to each other' there, forming a seal. Hereby W sp break-throughs 30, 31 or air passage openings are created, through which the external air is able to reach the top of the user's head.

30 At the same time, the wall sections 3' (see Fig. 7) formed hereby result in a reinforcement of the helmet, since these sections form an angle with the otherwise "smooth" outside surfaces 8, 9 of the helmet and in this way are able to largely absorb the impact energy acting e.g. in the direction of arrows 38, 39 (see Fig. 7) on the helmet 1 during a fall.

Said angle may have different values, as shown in the further embodiments.

It may also change with the progression of the sections (cf. the wave shapes in Fig. 8-10).

The cross-section in Fig. 7 shows that each of these wall sections 3' extends in the direction towards and again away from the respective other wall 2, 3. This results in a honeycomb structure that however, as shown in Fig. 6, does not extend over the entire area of the helmet 1, but only over the partial areas where said impact resistance must be present.

Fig. 8 shows a section, approximately along II-II in Fig. 6, of the two walls 2, 3 in wave shape, whereby the waves run approximately parallel or "synchronously" to each other. Here also the contours 16, 17 of the "smooth" outside surfaces of the helmet 1 are suggested again.

In a corresponding section, Fig. 9 shows the two walls 2, 3, also in wave shape, but whereby the waves of walls 2,3 are directed in opposite direction to each other, or are non-"synchronous". The contours are also suggested here by 0° reference numbers 16, 17.

20 The concept of this design of the invention, to extend the walls (see Fig. 7-9) or at least one wall (see Fig. 10) of the helmet 1 towards the other wall o B° and back again in order to achieve a corresponding reinforcement of the helmet need not be present over the entire helmet area. It is sufficient that it is present in those helmet areas that are at all at risk in the case of a fall.

25 The embodiment according to Fig. 10 shows that the outside wall 2 is not guided towards the other wall 3 and back again, but extends smoothly, so that tfo S only the preferred inside wall 3 is passed towards the outside wall 2 and back 0 0 again for reinforcement purposes, as is illustrated by sections 3' of inside wall 3 in Fig. 10. The smoothness of the outside wall 2 in this embodiment provides the 30 helmet 1 with a particularly pleasing appearance, while the inside wall 3 ensures O0 dt the desired rigidity and absorption of the impact energy in case of a fall.

a~ar~ -~l~lr~ll~ The embodiments of Fig. 8-10 show that the two walls 2, 3 still have a distance A from each other, thus facilitating the manufacturing using the blowing process. But it should be understood that the walls merge at the side edges or front ends 5 according to the illustration in the example of Fig. The bores 8 in the example in Fig. 9 illustrate that it is also possible in the case of these designs to ensure that the inside air is able to escape during a fall.

According to the illustration in the embodiment of Fig. 10 it is also possible to cover the air outlet opening with a valve of an elastic flap 9, whereby the flap 9 provides a certain resistance to the air escaping through the opening In principle, other valves are also useable. It is understood that said air outlet mE. is also may be provided in other embodiments.

Fig. 11 shows that one or more cushions 18 of a viscoelastic foam may be provided inside the helmet as impact protection. Such a foam has a particularly good shock-absorbing effect. The special advantage of this foam is that it is viscoelastic, i.e, is able to adapt to the shape of the head aiong the inside curve of the helmet 1 and maintains this adapted shape even if the helmet is removed from the head. This is more advantageous than an inside lining of an elastic foam material, since in the latter case the user must be offered several helmets with different thickness of layers of such an elastic foam material for selection.

0 o. 20 The design of helmet 1 according to Fig. 12 and 13 is characterised in that 0 .a the helmet part, forming the walls 2,3 are manufactured from plastic as separate shells and are then connected to each other ai their edges 19, preferably by welding or adhesion, so that the hollow chamber 4 between them is again closed.

As mentioned, the shell-shaped plastic parts forming the outside wall 2 and 25 the inside wall 3 may consist of deep-drawn or injected plastic. The walls 2, 3 are 00 *to manufactured separately and are then connected to each other, e.g. as described above.

Between the walls 2,3 are reinforcements that may form one part with at least one of the walls 2 or 3 (see Fig. 30 As an alternative, these reinforcements may be manufactured separated according to Fig. 14 and be connected to one of the walls, e.g. by adhesion. It is recommended that these reinforcements 26a are also made of plastic. In the ~PP I- L example of Fig. 13, these reinforcements 6a or 6b form a honeycomb pattern together with helmet walls 2, 3.

S&,d reinforcements 26 and also the possible designs of reinfcrcements illustrated in the examples of Fig. 14-16 are preferably proviaed over the entire helmet, but at least in the helmet area that may be stressed by impact energy during a fall, at least as indicated in Fig. 13 by arrow C.

The drawings illustrate that the reinforcements 26a extend from one wall 2 or 3 towards the other wall 3 or 2. Hereby it is possible that they progress at an acute angle to said walls (Fig. 13) or at a right angle thereto (Fig. 14-16).

The connection, e.g. by welding or gluing, of the two helmet walls 2, 3 at their edges 19 closes off the hollow chamber 4 inside these walls in an airtight manner. In i;'e case of a fall, the impact of the helmet results in a compression of the air inside these hollow chambers as additional absorption, and thus the absorption of the corresponding impact energy.

In addition it would also be possible to generate an overpressure of the air inside these hollow chambers of the helmet, either during the manufacturing or preferably via a valve. Especialy in the case of a plastic material used for walls 2, S 3 this results in greater elasticity due to a corresponding level of overpressure in S* order to achieve the desired resistance to impact energy, and particularly the 20 absorption of this impact energy.

If the material of the walls 2, 3 is very hard, a possible overpressure in the hollow chambers may be smaller than in the case of a plastic material that is somewhat more resilient. The precondition here is that no air outlet openings or bores exist in walls 2, 3.

25 But it is also possible to realise the invention with air outlet openings. In addition to the absorption or dampening of the impact energy due to reinforcements 26a, 26b, an air cushioning may be achieved in such a way that in one of the plastic helmet parts, preferably the outside wall 2, air outlet openings 8 are provided that permit an escape of the air inside the hollow chamber 4 if the two walls 2,3 are compressed due to an impact, but that still exhibit a certain resistance to the air passage. This resistance can be increased if, in the case of a t corresponding air outlet opening if there is an additional resistance on the outside, due to a flap 9 of elastic material that is positioned on this opening 8', said flap deflecting the air passage towards the outside. Naturally, a valve may be provided as an alternative.

It should however be emphasised that incorporation of an overpressure and the providing of outlet openings are not absolutely necessary, but represent only a special, additional design.

Fig. 13 also shows absorption strips 6 provided on the inside.

Fig. 15 shows a design with rods 26a that are constructed in one piece with one of the helmet walls, here the outside wall 2. In this embodiment, there is a specific, not too large distance A between the corresponding outside end directed towards the other wall 3--of rod 26a leading towards the inside surface of helmet wall 3 and the inside surface 3' of helmet wall 3.

The embodiment in Fig. 16 shows that rods 6a of wall 2 mesh with rods 6b of wall 3 in a comb-like manner and form the reinforcement. It is also possible to provide distances A here-if so desired.

Fig. 17 shows the arrangement of a fan wheel 25 in the top part of breakthrough 30 that is positioned rotatably via lateral journals 26, 27 in side walls 34, 35 of break-through 30. During driving, this ensures a suction effect of the a. eo S. warmed air inside the break-through 20 It is useful that the fan wheel is motor-driven by an appropriate (not shown) o 0drive unit that is driven by a solar cell (also not shown). It is useful that the solar cell is attached laterally on the helmet outside.

Fig. 18 shows a motorcycle crash helmet 50 that instead of a standard foamed polystyrene basic structure has a basic structure 53 in the form of a 25 helmet of the type described above. it is useful that the basic structure 53 is equipped with the corresponding reinforcement characteristics.

At the outside of the basic structure 53, in rigid connection with it, a helmet shell 51 is provided in Fig. 18 as an integral helmet. The helmet shell consists of an impact- and shock-resistant plastic, e.g. a polycarbonate. A swivel visor 52 is provided in the usual manner at the front of the helmet shell 51.

One advantage is that the two walls 2, 3 of such a helmet may consist of the same recyclable plastic, e.g. polystyrene, ABS, polyamide, or polycarbonate.

llW 9bBP~ sr*- s~ r r 14 After removing the absorption strips (foam elements) 6 and straps 7, such a bike crash helmet may be disposed off in its entirety.

The preferred material for manufacturing the helmet is polyethylene. Other suitable materials are also polypropylene, copolymer, polystyrene copolymer, acryl-butadiene-styrene, ABS, polyamide, polycarbonate, as well as PET.

The blown plastic material may contain luminescent, fluorescent dyes, color pigments. Because of this, the helmet, after having been exposed to light, emits light so as to be more easily seen in the dark. It is also possible that the plastic material for the helmet contains special odorous substances for ensuring a special marketing gag for children's bicycle crash helmets, etc.

It is to be understood that the helmet of this invention is not limited to use as a bicycle helmet but may be used for very different fields of application.

Wall thickness, elasticity, and hardness of the plastic may all be adjusted according to the desired requirements.

Although the invention has been described with reference to the illustrated preferred embodiments, it will be appreciated that various modifications may be made without departing from the scope or spirit of this invention.

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Claims

1. A bicycle helmet, comprising: a one-piece helmet body including a) a pair of concentrically spaced outer and inner helmet shells formed of plastic material; and b) means connecting said shells to form an unitary body, said shells containing openings, and said connecting means comprising an annular wall surrounding the respective opening, said annular wall having a generally double V-shaped cross sectional configuration and including successively axially converging and diverging wall portions in the direction from said outer shell to said inner shell.

2. A bicycle helmet as defined in claim 1, wherein said openings are arranged offset to each other in respect to their longitudinal orientation.

3. A bicycle helmet as defined in claim 1 or claim 2, wherein the outside 15 and/or low inside shell has ribs.

4. A bicycle helmet as defined in any one of the preceding claims, wherein said outer and inner helmet shells and said means connecting said shells are formed by blow moulding.

A bicycle helmet as defined in any one of the preceding claims, wherein the plastic material is selected from the group comprising polyethylene, polypropylene, copolymer, polystyrene copolymer, acryl-butadiene-styrene, n e C C Ce.. C. C* *r C C S C .C C C C *a 0* C C 40 C *CC C C. a CoCC 'CCC C *0a Ce C C C OCOC e poyamide, or poycarbonate.

6. A bicycle helmet as defined in any one of the wherein the average thickness of each shell is 1.5 to 2.0 mm.

7. A bicycle helmet as defined in any one of the wherein said plastic material contains a luminescent material.

8. A bicycle helmet as defined in any one of the wherein said plastic material contains a fluorescent dye.

9. A bicycle helmet as defined in any one of the wherein said plastic material contains a colour pigment. A bicycle helmet as defined in any one of the preceding claims, preceding claims, preceding claims, preceding claims, preceding claims, wherein in the area of the openings fan wheels are provided, ensuring an increased aeration of the openings.

DG C\WINWORD\DELILAHNODELETE55230.00C aarr qe =,I -16-

11. A bicycle helmet as claimed in claim 10, wherein the fan wheels are driven by the driving wind.

12. A bicycle helmet as claimed in claim 10, wherein each respective fan wheel is driven by a solar cell and the solar cell is attached to the exterior of the outside shell, preferably in a lateral area.

13. A helmet for use as a motor cycle crash helmet, wherein it includes a helmet as claimed in any one of claims 1 to 12 as a basic structure and wherein the basic structure carries at its outside an additional helmet shell in rigid connection.

14. A process for manufacturing a helmet as claimed in one of the preceding claims, wherein the helmet is blown inside a mould of at least one plastic tube in such a way that the tube is shaped inside a hollow chamber of the form into a double shell forming the helmet. A process as claimed in claim 14, wherein the wall thickness of the S 15 walls is adapted to a value desired in each case.

S.

16. A process as claimed in claim 15, wherein the adaptation is made by selecting a tube with a corresponding thickness.

17. A process as claimed in any one of claims 14 to 16, wherein after the blowing process but prior to removing the helmet from the mould, the walls are pressed against each other over partial areas so that they are coupled with each other there, preferably by adhesion, and wherein the partial areas are then cut l out, resulting thus in openings equipped with side walls.

18. A helmet for use as a bicycle crash helmet substantially as herein described with reference to any one of the embodiments illustrated in the .4 accompanying drawings.

19. A helmet for use as a motorcycle crash helmet substantially as herein described with reference to any one of the embodiments illustrated in the accompanying drawings. CA\WINWORDrELILAHNODELETE55230,DOC -17- A process for manufacturing a helmet substantially as herein described with reference to any one of the embodiments illustrated in the accompanying drawings. DATED: 9 February, 1996 PHILLIPS ORMONDE FITZPATRICK Attorneys for: GERHARD SPERBER 9 9 *9 9 *9 0* 9..6 *9 9 9* C:kMNWORD\DELILA+MCDELETEm55230.DOC ABSTRACT The present invention relates to a helmet, particularly a bicycle crash helmet of synthetic material, as well as a process for its manufacture. For the solution of the task of the invention, that is to make available a helmet of synthetic material which is able to be fabricated with essentially minimal manufacturing cost but with increased resistance against stress, it is suggested that the helmet be manufactured double-walled 3) from blown synthetic material. In addition, means should be provided which achieve a reinforcement together of the walls 3) of the helmet (1) during pressure stress, whereby these means can be realised preferably in the form of break-throughs Illustration Fig. 4