Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02829837 2014-02-11
SPORT HELMET
TECHNICAL FIELD
[0001] The present application relates to sport helmets, such as bicycle
helmets.
BACKGROUND OF THE ART
[0002] Bicycle helmets have now become ubiquitous for the bicycling
activity. In
road and urban riding, one specific helmet construction has become the norm:
that
consisting of the foam inner liner with an outer shell. The inner liner forms
the body
of the helmet in terms of volume and structural integrity. The inner liner is
typically
made of a structural foam material such as expanded polystyrene . An outer
shell
covers the liner and defines the smooth and decorative exposed outer surface
of the
helmet. The outer shell and liner are most often co-molded. Other components
include the attachment system inside the outer shell, by which the helmet is
secured
to the user's head.
[0003] The above-referred configuration is quite convenient in terms of
providing
suitable head protection, while being lightweight. Moreover, in some
instances,
numerous vents may be defined in the helmet to allow air circulation and the
exhaust of sweat, which is often necessary in warmer riding weather.
[0004] Helmets have been shown to be non-optimal in terms of aerodynamics,
notably because of the presence of such vents causing additional drag.
Accordingly, helmets used in competitions have recently been designed with
fewer
vents to limit drag losses. For example, Time trial helmets are often with
very few
vents. However, such helmets may not be as comfortable in warm weather.
SUMMARY
[0006] Therefore, it is an aim of the present disclosure to provide a
helmet that
addresses issues associated with the prior art.
[0006] In accordance with the present disclosure, there is provided a
helmet
comprising: an inner liner made of foam material forming a body of the helmet,
the
inner liner having a convex outer surface and a concave inner surface defining
a
cavity for receiving the wearer's head, the inner liner having a plurality of
beams
extending from front to rear of the helmet and spaced apart to form vents
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therebetween, the vents being free of foam material between adjacent beams; at
least one rigid bridge member comolded with the inner liner to be partially
concealed
in the inner liner, the at least one bridge member having at least one bridge
projecting out of the foam material of two adjacent beams and extending
transversely in at least one of the vents; and means to attach the helmet to a
wearer's head.
DESCRIPTION OF THE DRAWINGS
[0007] Fig. 1 is a perspective view of a sport helmet in
accordance with an
embodiment of the present disclosure;
[0008] Fig. 2 is an assembly view of a cage of the helmet of Fig.
1;
[0009] Fig. 3 is a perspective assembled view of the cage of Fig.
2;
[0010] Fig. 4 is a rear view of the helmet of Fig. 1; and
[0011] Fig. 5 is a schematic showing the typical head orientation
of a rider on a
bicycle.
DETAILED DESCRIPTION
[0012] Referring to the drawings, and more particularly to Fig.
1, there is
illustrated a helmet 10 in accordance with the present disclosure. The helmet
10 is
of the type that is used for bicycling and like sporting activities.
[0013] For simplicity, an attachment system is only summarily
shown as 11. The
attachment system is typically anchored to an interior of the helmet and
features
straps for the helmet to be strapped to the user's head. The attachment system
may also comprise rigid attachment components in the rear of the helmet, to
adjust
the helmet to a circumference of the wearer's head. Hence, although summarily
shown, the helmet 10 has such attachment means of any appropriate form.
[0014] Referring concurrently to Figs. 1, 2 and 3, the helmet 10
has a generally
hemispherical shape formed by an inner liner 12, an outer shell 13 and a cage
14.
By its hemispherical shape, the helmet 10 has an inner concave surface and
outer
convex surface, with the top and side of the wearer's head being received in
the
inner concavity. It is observed that various padding layer, not shown, may be
disposed against the inner concave surface, as interfaces between the inner
liner 12
and the wearer's head to improve comfort.
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[0015] The inner liner 12 is typically made of foam (e.g., expanded
polystyrene or
the like) and constitutes the major component of the helmet 10 in terms of
volume.
Moreover, the foam is of the type being generally rigid and hence providing
the
structural integrity to the helmet 10, in terms of maintaining its shape. In
other
words, the foam liner is not of the resilient type that is supported by a
rigid shell, but
rather of the type that is the main structural component of the helmet 10.
[0016] The outer shell 13 is integrally connected to the inner liner 12 and
forms
the major portion of the exposed convex surface of the helmet 10. The integral
connection may be achieved by way of adhesives or co-molding (i.e., molding of
the
inner liner 12 with the outer shell 13 positioned in the mold cavity
beforehand). The
outer shell 13 is made of a plastic layer, such as polycarbonate or the like.
The
outer shell 13 defines the smooth and decorative outer surface of the helmet
10.
[0017] Cage 14 is also co-molded with the liner 12 and substantially
concealed
inside the inner liner 12, with parts of the cage 14 projecting out of the
liner 12 as
described below. The cage 14 is an additional structural component of the
helmet
10. Moreover, the cage 14 has an impact on the improved aerodynamics of the
helmet 10 over existing foam liner helmets in the manner described below.
[0018] The liner 12 has a plurality of beams 20 and 21 extending in a
streamline
direction from front 22 to the rear 23 of the helmet 10, and forming the
hemispherical body of the helmet 10. A pair of peripheral beams 20 are
provided on
opposite sides of the helmet 10 to form the circumference of the helmet 10.
The
peripheral beams 20 therefore form an annular shape about the wearer's head,
starting from the front 22 to the tail 23. It is observed that the peripheral
beams 20
may be ergonomically designed to surround the ears of the wearer. Moreover,
the
peripheral beams 20 may have openings such as those illustrated by 24 and 25,
to
allow air circulation/moisture evacuation.
[0010] Likewise, inward beams 21 extend in the streamline direction from
the
front 22 to the rear 22 of the helmet 10. It is observed that the peripheral
beams 20
are all interconnected at the front 22, to then diverge from the front 22, and
converge toward the rear 23. The inward beams 21 are spaced apart from one
another and from the peripheral beams 20, thereby forming vents 30, with
pointy
end shapes. As shown, the vents 30 are elongated slots extending from a
frontal
portion to a rearward portion of the liner 12. The vents 30 are not obstructed
by
transverse portions of foam liner, i.e., the foam material bounds the
periphery of the
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vents from a front pointy end 30A to a rear pointy or open end 30B, with the
entire
volume of the vent being free of foam material.
[0020] The cage 14, as shown in Figs. 2 and 3, may consist of numerous
segments, such as the frontal segment 40, the central segment 50 and the rear
segment 60. The three different segments 40, 50 and 60 may each be
individually
molded and assembled in the manner shown in Fig. 3. Other configurations are
considered, such as the use of a pair of segments or of multiple parts to form
the
configuration shown in Fig. 3.
[0021] The frontal segment 40 has a transverse bridge member 41. Transverse
bridge member 41 is referred to as being transverse in relation to the front
to rear
streamline orientation of the helmet 10. The transverse bridge member 41 is
constituted of a middle bridge 42 and a pair of side bridges 43. It is
observed that
the front edges of the middle bridge 42 and the side bridges 43 are concave,
forming a V shape concavity. As explained hereinafter, this concave shape is
designed to increase the air intake in the vents 30. Moreover, the front edges
of the
bridges may have downwardly projecting lips 42A/43A, rigidifying the bridges
in a
transverse orientation of the helmet 10. However, so as to reduce the drag,
the lips
42A/43A, and similar lips of other bridges, are of relative small dimensions,
such as
a rectangular section of 2.0mm x 2.0mm. Ribs of similar dimensions as the lips
42A/43A may also be provided on undersides of the bridges 42 and 43, to
increase
the rigidity of the bridges. Openings 44 are defined at the intersection
between the
middle bridge 42 and the side bridges 43. Other openings 45 are provided at
ends
of the side bridges 43. The openings 44 are used to interconnect the frontal
segment 40 to the central segment 50, as described hereinafter and shown in
Fig. 3. The openings 45 allow foam penetration therethrough in the co-molding
process between the inner liner 12 and the cage 14.
[0022] A U-shaped strip 46 projects downwardly from tips of the side
bridges 43.
The U-shaped strip 46 is typically integral with the side bridges 43. A U-
shaped
base 47 is connected to a bottom of the U-shaped strip 46. The strips 46 and
47
constitute anchoring elements of the cage 14 in that they will be concealed
and
captive in the inner liner 12.
[0023] Arms 48 project laterally from opposite sides of the U-shaped base
47, for
alignment with the central segment 50. It is observed that triangular tabs B
are
provided all over the U-shaped strip 46. These triangular tabs are also found
in the
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central segment 50 and the rear segment 60, and are used to properly position
the
cage 14 in the mold prior to the co-molding step, by abutment with the mold
cavity
surface.
[0024] Still referring to Figs. 2 and 3, the central segment 50 is
shown as having
another transverse bridge member 51. The transverse bridge member 51 also
comprises a middle bridge 52, but two pairs of side bridges 53 on each side of
the
middle bridge 52. In similar fashion to the bridges 42 and 43, the bridges 52
and 53
show a concave edge, for instance with a V like shape, etc, with lips 52A/53A.
Arms
54 project forwardly from the junction between the middle bridge 52 and a
first set of
the side bridges 53. The arms 54 will be received in the openings 44 of the
frontal
segment 40 in the manner shown in Fig. 3. Hence, when the cage 14 is co-molded
to the liner 12, the foam material of the liner 12 will hold the arms 54 fixed
relative to
the openings 44 and thus maintain the frontal segment 40 and central segment
50
interconnected. Openings 55 are rearwardly positioned relative to these arms
54
and will serve a similar purpose by receiving corresponding arms of the rear
segment 60, in the manner shown hereinafter. Other openings 56 are defined at
various locations in the side bridges 53. These openings 56 allow foam
penetration
through the transverse bridge member 51 in the co-molding process. It is shown
that some fins 56A are lodged at various locations along the side bridges 53,
and
such fins increase the contact surface between the foam of the liner 12 and
the
cage 14, to increase the bond therebetween after co-molding.
[0025] Loops 57 are provided on opposite sides of the central
segments 50 and
form the base of the transverse bridge member 51. Clearances 58 are defined at
the tips of the loops 57, and will accommodate the tips of the arms 48 of the
frontal
segment 40. Loops 59 relate the loops 57 to a remainder of the transverse
bridge
member 51. Both sets of loops 57 and 59 are concealed within the inner liner
12
and retained by the foam material. The loops 57 and 59 may allow air
circulation
therethrough if vents are provided thereat in the liner 12. Slots 59A are
provided in a
front portion of the central segment 50, the slots 59A being used as anchors
for
straps of the attachment system 11.
[0026] The rear segment 60 also has a transverse bridge member 61
made of a
middle bridge 62 and pairs of side bridges 63 on opposite sides of the middle
bridge
62, with lips 62A and 63A similar to the lips 42A/42B. Openings 64 are located
on
opposite sides of the middle bridge 62 and allow foam penetration therethrough
CA 02829837 2013-10-09
during the co-molding process between the liner 12 and the cage 14. Arms 65
project forwardly, and will be received in the openings 55 of the central
segment 50.
Fingers 67 are also defined as projecting from side bridges 63. These fingers
67
will contact the central segment 50 to increase a contact surface between the
central segment 50 and the rear segment 60 of the cage 14. In a similar
fashion to
the central segment 50, loops 68 and 69 are provided on both ends of the
transverse beam member 61. The loops 68 and 69 form the base of the transverse
beam member 61. A plurality of rearward strips 70 project from the various
edges
of the transverse beam member 61 and form an arched portion, defining the rear
portion of the cage 14 at the rear 23 of the helmet 10.
[0027] Referring to Fig. 4, a connection block 71 is a node for the strips
70, which
converge to the block 71 and are integral therewith. The block 71 has a pair
of slots
72 of elongated shape, parallel to one another. The block 71 is embedded in
the
foam material of the inner liner 12, but corresponding clearances are defined
in the
foam material of the inner liner 12 and the outer shell 13, for the slots 72
to be open
to an inner surface and outer surface of the helmet 10. A strap of the
attachment
system 11 may be anchored to the helmet 10 by looping through the slots 72. In
an
embodiment, a single strap extends from one ear to another and passes through
the slots 72. Accordingly, the strap is well anchored to the back of the
helmet 10, by
passing through the slots 72 and thus by looped around a portion of the helmet
10
including the inner liner 12, and the cage 14. The outer shell 13 may also be
present at the anchor location. Likewise, an end of the straps of the
attachment
system 11 are anchored to the central portion 50 of the cage 14, by passing
through
the slots 59A. The straps of the attachment system 11 are therefore comolded
into
the helmet 10, and are anchored to the parts of the helmet 10 featuring both
the
inner liner 12 and the cage 14, i.e., parts with relative high structural
properties.
[0028] Referring to Fig. 1, it is shown that the various middle bridges 42,
52 and
62, and side bridges 43, 53 and 63 project out of the foam material of the
beams 20
and 21 bounding the vents 30, and are spaced apart from one another, from
front
22 to rear 23. The bridges 42, 43, 52, 53, 62 and 63 are all transversely
positioned
in the vents 30 of the helmet 10, relative to the streamline orientation
(i.e., from front
22 to rear 23). Hence, the bridges 42, 43, 52, 53, 62 and 63 act as the sole
structural members between the beams 20 and 21. The bridges 42, 43, 52, 53, 62
and 63 are made of a rigid polymer, such as Nylon 6, among other
possibilities.
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According to an embodiment, the portion of these bridges extending through the
vents 30 are substantially planar. These bridges are hence a substitute for
transverse bridges of foam material. However, in comparison with foam
material,
for a same structural support, these bridges are substantially thinner.
Accordingly,
the transverse drag surface of the helmet 10 is reduced over the substantially
thicker bridges of foam material, resulting in a reduced drag coefficient on
the air
intake side of the vents 30. Hence, the bridges perform a similar structural
function
as the prior-art foam bridges did, while providing a more aerodynamic shape.
As
shown, a single vent 30 may feature three of the these bridges in front-to-
rear
succession.
[0029] Referring to Fig. 5, a relatively usual rider position on a road
bike is
shown, the rider position being that of a racing or cyclosport position. Due
to the
inclination of the torso (i.e., 30 degrees from the horizon), the anterior-
posterior axis
at the level of the eyes is about 20 degrees below the horizon (when the rider
is on
a substantially horizontal surface). The plane of the portion of the bridges
42, 43,
52, 53, 62 and 63 extending through the vents 30 is oriented as a function of
the 20
degrees below the horizon, i.e., at least some of these planes are oriented to
be
parallel to the streamline of the bike moving in a straight line. The stream
line of the
bike is shown by axis X in Fig. 5. Stated differently, when the bottom of the
inner
liner 12 is on a horizontal plane and hence the cranial-caudal axis of the
helmet 10
is vertical, i.e., as if the rider is off the bike and standing vertical
(i.e., parallel to axis
Y in Fig. 5), an anterior-posterior orientation (from front 22 to rear 23 in
Fig. 1) of the
planes of at least some of the bridges 42, 43, 52, 53, 62 and 63 is at +20
degrees
degrees from the horizon.
[0030] While the bridge members 40, 50 and 60 are described as being part
of
the cage 14, it is considered to have the bridge members 40, 50, 60 being
individually present in the helmet 10, and not related as a cage. However, in
such a
case, there should be a sufficient substantial portion of bridge material
concealed
inside the inner liner 12, to provide suitable anchoring of the bridge members
40, 50
and 60 in the inner liner 12.
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