Illumination – Supported by vehicle structure – Light modifier
Reexamination Certificate
1999-05-25
2001-05-22
Cariaso, Alan (Department: 2875)
Illumination
Supported by vehicle structure
Light modifier
C362S528000
Reexamination Certificate
active
06234655
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an automobile headlamp having a reflector supported by an aiming mechanism in a lamp body so that the tilting direction of the reflector can be regulated, and more particularly to an automobile headlamp having a reflector fitted with a light-distribution switching mechanism for alternatively switching between light distribution for a low beam and that for a high beam.
2. Description of the Related Art
In a conventional headlamp of the sort mentioned above, a reflector
2
fitted with a light source bulb
3
is as shown in
FIGS. 15 and 16
tiltably supported by an aiming mechanism
4
(including two aiming screws
4
a
and
4
b
, two nut members
5
a
and
5
b
on the reflector
2
side which are screwed onto the respective screws
4
a
and
4
b
, and one ball joint
4
c
) in a lamp body
1
. A direction of optical axis L can thus be regulated by tilting the reflector
2
by pivoting the aiming screws
4
a
and
4
b
around a horizontal tilting axis Lx (an axis connecting the nut member
5
b
and the ball joint
4
c
) and a vertical tilting axis Ly (an axis connecting the nut member
5
a
and the ball joint
4
c
). Reference numeral
8
denotes a front lens which is integrally fitted in the front opening of the lamp body
1
.
Moreover, a shade
6
for blocking off part of the light directed to the reflector
2
in order to form a predetermined light-distribution pattern is provided around the bulb
3
. The shade
6
is supported by a longitudinally-slidable slider
7
a
and capable of moving along the optical axis L. When the shade
6
is moved to a solid-line position of
FIG. 16
, then a part of the reflector
2
is functioning as an effective reflective surface, whereby the light distribution for the low beam is formed, whereas when the shade
6
is moved to an imaginary-line position of
FIG. 16
, then the remaining part of the reflector
2
is also functioning as an effective reflective surface, whereby the light distribution for the high beam is formed. In other words, the slider
7
a
caused by a motor
7
b
to run longitudinally forms a light-distribution switching mechanism
7
for alternatively switching between the light distribution for the low beam and that for the high beam.
Since the light-distribution switching mechanism
7
is provided for the reflector
2
in the aforementioned conventional headlamp, however, a reflector-side load (weight) applied onto the aiming mechanism
4
(including the two aiming screws
4
a
and
4
b
, the two nut members
5
a
and
5
b
, and the one ball joint
4
c
) becomes heavy. Consequently, smooth optical axis adjustment becomes difficult because the pivoting torque of the aiming screws
4
a
and
4
b
is stronger.
There are also other problems arising from failing to obtain adequate light distribution because the bending of the aiming screws
4
a
and
4
b
used for supporting the reflector
2
in a cantilever style causes the reflector
2
to sag, and making light distribution oscillate vertically because the reflector
2
is pivoted in the vertical direction.
SUMMARY OF THE INVENTION
An object of the present invention made in consideration of the foregoing problems is to provide an automobile headlamp so constructed that even though a light-distribution switching mechanism for alternatively switching between light distribution for a low beam and that for a high beam is provided for a reflector, no greater load is applied to an aiming mechanism for supporting the reflector in such a way that the tilting direction of the reflector can be regulated.
In order to accomplish the above object, in this invention, an automobile headlamp is comprised of a container-like lamp body, a discharge bulb provided in the lamp body, a reflector which is installed in the lamp body and used for reflecting and distributing light from the discharge bulb forwardly, and an aiming mechanism which is held between the reflector and the lamp body and used for supporting the reflector with respect to the lamp body in such a way as to adjustably tilt the reflector. The aiming mechanism includes one ball joint which is held between the reflector and the lamp body and forms the tilting fulcrum of the reflector, two aiming screws which are each rotatably supported by screw inserting holes bored in the lamp body and forwardly extended, and nut members which are each screwed onto the aiming screws, integrally fitted to the reflector and moved longitudinally along the aiming screws when the aiming screws are pivoted.
The reflector is fitted with a light-distribution switching mechanism for alternatively switching between light distribution for a low beam and light distribution for a high beam and that horizontally extended portions are formed in parallel to the aiming screws in order to carry the respective nut members in the lamp body.
The reflector is tilted by pivoting the aiming screws so as to make the tilting of the optical axis of the lamp adjustable and the light-distribution switching mechanism is driven to alternatively switch between the light distribution for the low beam and that for the high beam.
Although the reflector-side load (weight) applied via the nut members to the aiming mechanism is greater to the extent that the reflector is fitted with the light-distribution switching mechanism, the reflector-side load (weight) applied to the aiming mechanism becomes decreased in comparison with the conventional structure because the nut members are carried by the horizontally extended portions formed in the lamp body.
Consequently, the pivoting torque of the aiming screws remains small. Moreover, the aiming screws become hardly bent, thus resulting in restraining the reflector from sagging and vertically pivoting.
In this invention, each of the nut members includes a plastic ball nut which is screwed onto the aiming screw, and a plastic ball bearing which is fitted to the bracket of the reflector, used for relatively pivotally supporting the ball nut around the vertical and horizontal axes of the nut and baffling the ball nut around the longitudinal axis of the nut in the automobile headlamp of this invention.
When the aiming screws are pivotally turned, the nut members as the fulcrum of the reflector are moved longitudinally (along the aiming screws) with respect to the fixed fulcrum (the ball joint), so that the tilting of the reflector is adjusted. However, the ball nuts screwed onto the aiming screws are pivoted (around the vertical or/and horizontal axes of the respective nuts) with respect to the ball bearing integrally fitted to the reflector, whereby no unexpected stress is generated between the ball nuts (the aiming screws) and the ball bearing (the nut members).
In this invention, the horizontally extended portion is formed with a pair of vertically opposed horizontal ribs, wherein the ball bearing of the nut member is provided with elastic contact leaves like leaf springs which are pressure-welded to the respective horizontal ribs and wherein the nut member is longitudinally slidably held between the opposed horizontal ribs in the automobile headlamp of this invention.
The nut member is longitudinally slidably held between the opposed horizontal ribs to ensure that the vertical pivoting of the reflector is suppressed.
In this invention, a contact portion which is brought into contact with the horizontally extended portion of the nut member is in an arcuate form extended in the direction in which the nut member is moved longitudinally in the automobile headlamp of this invention.
The slide frictional force between the arcuate contact portion and the horizontal extended portion (the horizontal rib) on the nut member side is smaller than that in a case where the horizontal extended portion and the contact portion on the nut member side are flat, so that the nut member is allowed to move slidably and smoothly along the horizontal extended portion (the horizontal rib).
In this invention, the elastic contact leaf in the form of a leaf spring is provided on the upper si
Shirai Katutada
Suehiro Yoshio
Cariaso Alan
Koito Manufacturing Co. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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