Note: Descriptions are shown in the official language in which they were submitted.
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FIEI.D OF TIIE INVENTION
The present invention relates to safety or protective
helmets for cyclists' heads.
BACX5~0UND OF THE INVENTION
It is known in the art to provide safety helmets composed
of two different thicknesswise layers: an outer, rigid, impact-
resistant shell - usually relatively thin - (e.g. polyvinyl
chloride (PVC or ABS) and an inner, softer, shock-absorbent layer -
usually thicker than the outer shell (e.g. expanded polystyrene
foam). These helmets offer a fair protection for a first impact,
but are often shattered under a multiple impact fall of the
cyclist. Indeed, the relatively thin impact-resistant shell tends
to fissure after the first impact, the following blows fracturing
and spliting the helmet into many pieces, since the shock-absorbent
layer usually does not withstand direct blows. This is obviously
undesirable, since the purpose of the safety helmet is to protect
the helmet wearer' 6 head, and it most preferably should not be
fragmented on the first blow if it is to withstand many blows. A
thicker outer shell can be used to increase the impact resistance,
but the helmet can then become quite heavy because of the excessive
material weight.
To mitigate this resistance deficienay, a helmet
prototype was designed in which a thick layer of polypropylene,
replacing the usual polystyrene foam (the polypropylene being
lighter and more resistant than the polystyrene) was covered with
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a thin shell of hard impact-resistant material such as PVC plastic.
The increased resistance proved that the choice of the
polypropylene was wise, but the helmet lacked the shock absorption
quality that it had before because of the absence of the shock-
absorbing layer and the polypropylene proved to be much lessresistant under warm weather conditions than it was under normal
weather conditions because of the softening of the polypropylene
under such conditions. Therefore, though the multi-impact
resistant polypropylene seemed a good material choice, it was still
not good enough.
O~JECT~ OF TNE INVENTION
It is the general object of the present invention to
provide a safety helmet of the character described that will
protect its wearer against head injuries with a maximum efficiency,
even during multiple-impact falls of the wearer.
It is an important object of this invention to provide a
safety helmet of the character described of light weight.
It is another object of the present invention that the
safety helmet be well ventilated.
~UMMARY OF TNE INVENTION
In accordance with the objects of the invention, the
present invention consists of a safety helmet comprising three
thicknesswise layers~
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a) a thin impact-resistant smooth outer shell;
b) a memory-material intermediate layer; and
c) a shock-absorbing inner liner;
said intermediate layer being able to regain its form after an
impact, said inner liner conforming with, and being adapted to fit
the head of a wearer, said intermediate layer conforming with, and
adhering to, the outer surface of said inner liner, said outer
shell conforming with, and adhering to, the outer surface of said
intermediate layer.
Preferably, said intermediate layer extends downwardly
beyond said outer shell, thus forming a lower peripheral extension.
Advantageously, said outer shell, said intermediate layer
and said inner liner form ventilation openings that correspond from
one layer to the other.
Preferably, said outer shell extends inwardly into said
ventilation openings thus covering at least a portion of the
intermediate layer.
Profitably, said outer shell and said intermediate layer
are joined by a butt joint; and further including a peripheral
sealer strip overlying and straddling said butt joint.
Advantageously, said intermediate layer further comprises
spaced transversely-extending grooves made at its outer surface and
adapted to be engaged by helmet retaining straps, said grooves
extending downwardly to the inner surface of said lower
peripherical extension of said intermediate layer.
Alternately, said intermediate layer further comprises
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spaced transversely-extending grooves made at its outer surface and
adapted to be engaged by helmet retaining straps, said straps
extending transversely to at least two of said ventilation
openings .
Preferably, said safety helmet defines a front and a rear
section adapted to extend across the forehead and the back of the
head of the wearer, respectively, said intermediate layer being
thicker at said rear section.
Profitably, said inner liner further comprises cushioning
patches adhering to and protruding from its inner surface, said
cushioning patches adapted to space said inner liner from the head
of a wearer when in contact with said head.
Advantageously, said outer shell and intermediate layer
form inward elongated grooves and said inner liner forms outward
elongated grooves.
Preferably, said inward elongated grooves register with
said outward elongated grooves, at least some of said ventilation
openings being elongated and located through said elongated
grooves.
Profitably, said intermediate layer and said inner liner
are relatively of the same thickness.
In one embodiment of the invention, said intermediate
layer and said inner liner are interconnected by key means.
Preferably, said safety helmet defines front and rear portions; and
said key means including a first key member, interconnecting the
front portions of the intermediate layer and inner liner, and a
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pair of second key members, interconnecting the rear portion of the
intermediate layer and inner liner. Advantageou~ly, each key
member consists of a dovetail joint defined by: (a) a frusto-
conical bore, made into the thicknes~ of said intermediate layer
with the largest diameter end being on the exterior face of said
intermediate layer; and (b) a projection integrally projecting
from said inner liner and freely filling the volume defined by and
sitting into and complementarily sized to fit inside said frusto-
conical bore.
BRIEF DB~CRIPTION OF THE DRAWING~
Figure 1 is a partial side elevational view of a first embodiment
of safety helmet of the invention;
figures 2-2a are top plan views of the two embodiments of helmet
according to the invention, with fig 2a showing the helmet in
partly broken view;
figure 3 and 4 are longitudinal sections taken along lines 3-3 and
4-4, respectively, of figure 2;
figure 5 is a cro~s-sectional view, at an enlarged scale, taken
along line 5-5 of figure 1; ~ -
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figure 6 is a partial cross-sectional view, at an enlarged scale,
taken along line 6-6 of figure 4;
figure 7 is a partial section, at an enlarged scale, taken within
circle 7 of figure 3; and ~;
figures 8-9 are enlarged cross-sectional views taken about lines 8-
8 and 9-9 respectively of figure 2.
DETAILED DE8CRIPTION OF THE INVENTION
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As it can be seen on figure 5, the safety helmet lo of
the present invention is composed of three distinct thicknesswise
layers of different composition: an outer shell 12, an intermediate
layer 14 and an inner liner 16.
Outer shell 12 is made of a rigid material, such as
polyvinyl chloride plastic (better known as PVC) or polystyrene
plastic, and its outer free surface is advantageously smooth so
that the helmet may be as aerodynamic as possible. Although the
thickness of shell 12 is very small compared to the thickness of
the whole helmet, its presence is nevertheless very important, for
it resists to impacts of a relatively strong intensity. Moreover,
its smoothness is highly desirable, especially when the wearer is
cycling at high speed, for the aerodynamic drag induced by the
helmet-wearing speeding cyclist becomes a factor in the
performance of the cyclist.
Intermediate layer 14 is made of a fairly rigid memory
material, i.e. a material which will recover its initial form after
having been deformed due to an impact blow. This material is
preferably expanded polypropylene plastic. Memory material 14
needs to be thicker than outer shell 12, because it is less rigid
and if it h~ere as thin as outer shell 12, it would be torn apart
when an impact would occur. The thickness of memory material layer
14 is therefcre approximately half of the thickness of helmet 10.
This layer 14 is very important, because although impact-resistant
shell 12 may suffice to protect the cyclist's head against a first
blow, if a multi-impact fall occurs, it is desirable that the
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helmet remain whole to protect the head during the entire fall.
Layer 14, instead of being shattered after one impact, is designed
to recover its form after each impact on the helmet, due to the
material memory. The wearer of the helmet would therefore be
protected during the entire fall, instead of being protected
against the first blow only.
Inner liner 16 is composed of a softer, alhtough quite
resistant, plastic material, preferably expanded polystyrene foam.
This third layer is desirable because of its capacity to distribute
the energy of the impact over a broader area, thus "feeling"
smoother for the cyclist wearing the helmet. In other words, liner
16 distributes a blow on the helmet more evenly on the head, -
instead of transferring it all to a single point, which is much
less painful for the helmet wearer. The thickness of inner liner
16 is similar to that of intermediate layer 14, i.e. about half of
the thickness of the whole helmet.
The combination of the three layers, i.e. thin impact~
resistant smooth outer shell 12, memory material intermediate layer
14 and shock-absorbing inner liner 16, offers a protection against
small impacts, against multi-impact falls and generally prevents
the wearer's head from injuries. -
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As shown on figure 1, intermediate layer 14 is defined at
its lower periphery by a bottom rim portion 14a that projects
downwardly beyond outer shell 12. Therefore, outer shell 12 does
not cover the entire outer surface of helmet 10, for bottom rim 14a
is the outer free surface of helmet 10 at the lower periphery of
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helmet lo. other than that, outer shell 12 conforms with, and
adheres to the outer surface of intermediate layer 14.
Figure 3 shows that intermediate layer 14 has an
increased thickness at the lower rear part 14b of helmet 10, to
better protect the wearer's head, just above the nape, against
shocks, since it is often on the back of the head that a person
receives a blow when falling. Also, this increase in thickness in
the back of helmet 10 confers a shape to helmet 10 which is more
aerodynamic.
The joint between outer shell 12 and intermediate layer
14 is a butt joint, as shown on figure 5 at 34. Indeed, outer
shell 12 abuts at its lower periphery against a slight outward
peripheral protrusion 14c of intermediate layer 14, and a
peripheral sealer strip 18 overlies outer shell 12 and intermediate
. layer 14 and straddles joint 34.
As shown in figures 3 and 5, inner liner 16 conforms
with, and adheres to the inner surface of intermediate layer 14.
It is important to note that inner liner 16 covers the entire inner
surface of intermediate layer 14, consequently preventing that the
wearer's head come into contact with intermediate layer 14. This
is de~irable, because liner 16 iæ softer than layer 14 and not only
will it be more comfortable for the wearer's head to come into
contact with thiæ æofter liner 16 than with harder layer 14, but
alæo the liner must cover the whole inner æurface of helmet 10 to
provide a æhock-absorbing characteristic wherever the shock may
occur on helmet 10. Inner liner 16 conformæ with, and iæ adapted
to cover the wearer's head, including part of the forehead and the
back of the head just above the nape.
In the first embodiment of helmet illustrated in figures
1, 2, and 3-7, the intermediate layer 14 and the inner liner 16 are
fixedly secured to one another by a known glue compound, laid
therebetween, this glue compound being selected for its
compatibility with the constituting materials of the layer 14 and
liner 16. Alternately, this glue compound can be replaced by a
pair of front and rear anchoring members, 40 and 42, respectively,
being illustrated in figures 2a, 8 and 9 (second embodiment
helmet). Such anchoring members 40, 42, are generally considered
more efficient in interconnecting the layer 14 to the liner 16, and
thus, this second embodiment of helmet is accordingly the preferred
mode of helmet 10'. Each anchoring member 40, 42, 42, consists of
a key which interlocks the layer 14 with the liner 16. More
particularly, the single front key member 40, and the pair of rear
key members 42, 42, each consists of a dovetail joint made from a
frusto-conical bore made into the thickness of the intermediate
layer 14, and a complementarily-size projection integrally
pro~ecting from the inner liner and filling the volume defined by
and sitting into said frusto-conical bore. Since the diameteer of
said frusto-conical bore decreases from the exterior face of the
intermediate layer 14 to its interior face, and the complementary
projection of the inner liner 16 engaging said frusto-conical bore
sits freely into the latter, the joint is firm, since any bias to
spread layer 14 away from liner 16 will only further strenghten the
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joint, as can be readily understood by one skilled in the art.
As can be seen on figures 2-2a, a plurality of elongated
ventilation openings 20, 22 are practiced thicknesswisely through
helmet lo, i.e. through outer shell 12, intermediate layer 14 and
inner liner 16. Ventilation openings 20, 22 are positioned
symmetrically, relative to a central, vertical, lengthwise plane of
helmet lo. The frontal portion of helmet 10 is ventilated by
ventilation openings 20, which are adapted to be positioned just
above the wearer's forehead when the helmet is worn, while
ventilation openings 22 are positioned lengthwisely along elongated
grooves 24 which are formed thicknesswisely on the outer free
surface of helmet 10. Grooves 24 extend from the top of helmet 10
to the rear portion just above the rear lower part 14b of
intermediate layer 14, conforming to the general shape of helmet
10. The symmetry and the shape of grooves 24 provide a more
aerodynamic shape to helmet 10.
Figure 5 shows that the shape of outer shell 12 conforms
with grooves 24 of helmet 10. Also, outer shell 12 possesses
inward projections 12a (figure 6) that extend inwardly in
ventilation openings 20, 22 adjacent to intermediate layer 14, and
almost reach inner liner 16. These inward projections 12a confer
a smoother outer surface to helmet 10, since otherwise intermediate
layer 14 would be more exposed through the ventilation openings to
the wind and weather conditions.
Figure 4 shows that ventilation openings 20, 22 offer
long surfaces (relative to the entire length of helmet 10) through
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which the air may enter, thus refreshing the wearer and permitting
the wearer's head-generated humidity to escape through the helmet.
Ventilation openings 20, 22 thus create a much more comfortable
helmet for the wearer.
As can be seen in figure 5, inner elongated grooves 36
are formed on the inner surface of inner liner 16, inner grooves 36
registering with grooves 24 of the outer surface of helmet 10.
Helmet 10 is further provided with retaining straps 26,
28 of known construction (figurse 1 and 5) extending downwardly
under helmet 10. Retaining straps 26, 28 are equipped with length~
adjusters and chin straps (not illustrated), to permit the
attachment of the helmet on heads of different sizes.
As can be seen on figures 4 and 7, front retaining strap
26 is fixed at the front extremity of helmet 10, between frontal
ventilation openings 20 and top ventilation openings 22. Figure 7
shows how retaining strap 26 is inserted between outer shell 12 and
intermediate layer 14, in an elongated transversal groove 30
practiced on the outer surface of intermediate layer 14, this
groove being adapted and correctly dimensioned to receive and be
e,ngaged by retaining strap 26; this prevents retaining strap 26
from disengaging itself from helmet 10 ~it would have to be torn
away, but this would require a relatively forceful stress).
Transversal groove 30 extends in a downward arc, conforming to the
shape of helmet 10, until it reaches orifices (not illustrated)
allowing the retaining strap 26 to protruberate under helmet 10,
the orifices being positioned on the inner surface of bottom rim
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14a of intermediate layer 14. Figure 4 further shows that rear
retaining strap 28 is fixed in a rear ventilation opening 22, and
passes between intermediate layer 14 and inner liner 16 in a groove
similar to the groove of retaining strap 26, extending its two ends
downwardly and concurrently to a helmet 10 central, vertical,
lengthwise plane.
The free extremities of retaining straps 26, 28 extend on
one side and the other of helmet lo, thus allowing helmet 10 to be
secured on the wearer's head with above-mentioned chin straps,
strap 26 being adapted to extend adjacent to the temples and to
pass in front of the ears, and strap 28 being adapted to pass
behind the ears, straps 26 and 28 reaching each other under the
chin, thus roughly forming a V on each side of the wearer's head.
As can be observed on figures 3, 4 and 6, elongated
cushioned patches 32 are attached to the interior free surface of
inner liner 16, so that the contact of the wearer's head with
helmet 10 will be more comfortable for the wearer. Patches 32 are
strategically positioned where helmet 10 rests against the wearer's
head and they possess a thickness sufficient to space inner liner
16 from the wearer's head.
The resulting helmet is very light and complies with the
regulations governing the resistance to impact of such helmets
(e.g. A.N.S.I., S.N.E.L.L. in the United States, which is a
regulated test of cyclists' helmet resistance) due to the combined
layers of di~ferent materials. Indeed, under warm conditions which
have proven to reduce the resistance of polypropylene helmets due ~
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to its softening under such conditions, shock-absorbing liner 16 ~ ~
compensates to keep the helmet lo resistance above a certain -. -
acceptable level (this acceptable level being regulated by
S.N.E.L.L. tests). The resulting helmet therefore pos6esses a very ~ :
reliable resistance, even under multi-impact falls.
