Illumination – Supported by vehicle structure – Bicycle or motorcycle
Reexamination Certificate
2003-01-02
2004-08-10
Sember, Thomas M. (Department: 2875)
Illumination
Supported by vehicle structure
Bicycle or motorcycle
C315S082000, C315S083000
Reexamination Certificate
active
06773147
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a twin beam type headlight device for a motorcycle, having a pair of headlights, arranged left and right on the front face of a cowling that covers the front part of the motorcycle.
(2) Description of the Prior Art
To begin with, the luminous intensity distribution depending on the type of a bulb(light bulb) of a headlight for motorcycles will be explained. The case described here is assumed to be applied to a right-side traffic model and a left-side traffic model may be provided by reversing the right-side left.
FIG. 1
sectionally shows a typical example of a headlight. As shown in
FIG. 1
, it includes a reflector (reflecting mirror) b of a headlight a having a parabolic configuration. Recently, there has been a configuration in which a cut-less, clear or transparent lens c is used for the front face with a reflector b of a multi-reflector(multi-facet reflecting plate) so that a desired luminous intensity performance can be obtained by devising the shapes and arrangement of small mirror facets. Here, reference numeral d and e in
FIG. 1
designate a headlight bulb(light bulb) and headlight housing, respectively.
In riding a motorcycle, if it runs on a two-way traffic road, not on a one-way traffic road, the headlight is set at the low-beam position so that the projection of the headlight will not dazzle the drivers on oncoming vehicles. In a motorcycle having a pair of left and right headlights, in the case of right-side traffic as shown in
FIG. 2
, for example, it is necessary to create a right-side higher luminous intensity distribution in which only the projection of the light on the left or on the oncoming vehicle's side is set at the low beam position while the projection of the light on the right side or the opposite side is set at the high beam position. It should be noted that for a left-side traffic model, the distribution of light should be reversed right-side left.
Headlight bulbs for realizing the luminous intensity distribution as above can be roughly categorized into a double filament type shown in
FIG. 3 and a
single filament type shown in
FIG. 4. A
typical double filament type headlight bulb shown in
FIG. 3
has two filaments f
1
and f
2
for low and high beams incorporated in a glass tube. A cup g is disposed beneath low-beam filament f
1
and this cup g blocks the light emitted from the filament f
1
so that light will not reach approximately the lower half of the reflector. Cup g is designed so as to meet the predetermined specification of luminous intensity distribution.
On the other hand, as shown in
FIG. 4
, a single filament type headlight bulb has no cup, hence light emitted from filament h is designed to reach the whole surface of the reflector. In order to attain the luminous intensity distribution as shown in
FIG. 2
, it is generally known that the reflectors for a single filament type and double filament type headlights should have hatched areas shown in
FIGS. 5A and 5B
as their reflective areas, respectively. As seen in
FIGS. 5A and 5B
, since in the double filament type headlight, light emitted from the low-beam filament is blocked by cup g, hatched portions A and B should be formed greater than those of a single filament type headlight. Particularly, the double filament type headlight is configured so that the distance from the center to a point H is greater than the distance from the center to a point K in the single filament type headlight.
Up to now, the luminous intensity distribution depending on the type of a headlight bulb has been described. To sum up, a double filament type headlight uses a reflector which can be switched between the high and low beam positions but needs greater reflective areas as shown by the hatching in order to satisfy the required luminous intensity distribution. A single filament type headlight uses a reflector which is dedicated for the high or lower position and can function with smaller reflective areas as shown by the hatching.
Referring next to
FIGS. 6 and 7
, the character lines of left and right headlights
10
R and
10
L will be described.
FIG. 6
shows the character lines as the outline of headlights.
FIGS. 7 and 8
are front and partial side views of a motorcycle. As shown in
FIGS. 7 and 8
, a leg shield j covering the front of an unillustrated steering head pipe is projected forwards over the front wheel. A pair of left and right cutout holes K (with their edges forming the character lines) are formed in the projected portion and a pair of left and right headlights a, a are embedded. A cover m is provided on the upper side of headlights a, a of leg shield j while a (lower edge) character line n of leg shield j is formed on the lower side of the headlights. A shield screen n′ and a pair of left and right rearview mirrors o, o are provided along the upper edge of leg shield j. A front turn signal o
1
is provided on the front face of each rearview mirror o. A reference numeral p designates a front wheel; p
1
a front fork; q a handlebar; and r a front leg shield-rear.
As to the motorcycle's headlight, recently there has been a tendency toward twin beam type configurations in which a pair of separate lenses are arranged like ‘almond shaped eyes’ to create a stylish appearance or bold features. In
FIG. 6
, to create ‘almond shaped eyes’, the four vertexes A
1
(A
2
), B
1
(B
2
), C
1
(C
2
) and D
1
(D
2
) of each lens character are arranged so as to suffice the relation: distance A-B>distance C-D, and the figure becomes more like an almond shaped eye as the point D is positioned closer to the point C. Here, comparing
FIGS. 5A and 5B
with
FIG. 6
, to realize the right-side higher luminous intensity distribution(the luminous intensity distribution with the road-shoulder side higher in the right side traffic), the distance T-U of the reflector for a single filament bulb and the distance R-S of the reflector for a double filament bulb do not need to be very long.
FIG. 9
shows a configuration in which a pair of single filament type headlight reflectors are laid, on both the left and right side, over the ‘almond shaped eyes’ character lines (designated at k).
FIG. 10
shows a configuration in which a pair of double filament type headlight reflectors are laid, on both the left and right side, over the ‘almond shaped eyes’ character lines. It is known from
FIGS. 9 and 10
, when comparing the position of each hatched portion with the character line k, the right-side headlight reflector in both the cases, has a large enough margin with respect to the character line while as to the left-side headlight reflectors for both the single filament and double filament, the hatched portion is positioned close to the character line. Particularly, in the case shown in
FIG. 10
, the part designated at H is located outside the almond shaped eye character line k
0
, which is needed so as to be stylish, hence it is impossible to achieve the required luminous intensity distribution if no countermeasure is taken.
To deal with this, the character line has to be spread outwards as indicated by k
1
in FIG.
10
. However, the lower right point D
1
of the reflector also displaces outward, or downwards and rightwards, so that the boldness of almond shaped eyes is lessened.
However, as shown in
FIGS. 9 and 10
, in the prior art in which a pair of single filament type headlights are arranged on both the left and right sides, the headlight on the left side (oncoming vehicle's side) should be allotted for that for low beam only while the headlight on the right side(road-shoulder side) should be allotted for that for high beam only, whereby only the left side low-beam only head light is activated in low-beam running, and the left side low-beam only head light and the right side high-beam only head light are both activated in high-beam running. Illustratively, when this motorcycle meets other vehicles running in the opposite direction, it should run in the normal travel mode or low-beam mode. Accordingly, on
Kakizoe Takashige
Tsushima Hisao
Negron Ismael
Nixon & Vanderhye P.C.
Sember Thomas M.
Suzuki Motor Corporation
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