Illumination – Light source and modifier – With sealing means or artificial atmosphere
Reexamination Certificate
1999-04-01
2001-05-15
Sember, Thomas M. (Department: 2875)
Illumination
Light source and modifier
With sealing means or artificial atmosphere
C362S546000, C362S548000, C362S549000, C362S362000
Reexamination Certificate
active
06231211
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vehicle lamp fabricated by fitting a bulb as a light source into a bulb fitting hole provided in a lamp body by bayonet engagement, and fitting an annular gasket in between a flange portion provided on the periphery of a bulb socket and the peripheral edge portion of the bulb fitting hole whereby to seal the bulb fitting hole, and more particularly to a vehicle lamp having a lamp body and a front lens which are integrally formed by blow molding.
2. Related Art
In order to decrease the number of parts constituting a lamp, a conventional vehicle lamp is constructed as shown in FIG.
11
through the steps of integrally forming a lamp body portion
2
and a front lens portion
3
by blow molding into a hollow body lens unit
1
, fitting a bulb
5
as a light source into a bulb fitting hole
4
formed in the lamp body portion
2
of the body lens unit
1
by bayonet engagement and fitting an annular gasket
7
in between a flange portion
6
a
provided on the periphery of a bulb socket
6
and the peripheral edge portion
4
a
of the bulb fitting hole whereby to seal the bulb fitting hole
4
.
The gasket
7
has a transverse cross section so that its wall thickness is gradually reduced toward the inner peripheral side so as to make easy the mounting of the gasket on the bulb socket
6
.
In the case of such a conventional lamp, however, since the body lens unit
1
essentially consisting of the lamp body portion
2
and the front lens portion
3
is formed by blow molding, the wall thickness of the peripheral edge portion
4
a
of the bulb fitting hole varies in the peripheral direction, and the annular gasket
7
protrudes from the flange portion
6
a
at the time the bulb
5
is fitted into the bulb fitting hole
4
, thus posing a problem arising from insufficient waterproofing.
More specifically, as the hollow body lens unit
1
is formed by blow molding through the steps of supplying compressed air into a plastic parison to make the plastic material follow the molding surface by expanding the parison, there develops a variation in plate thickness (hereinafter called a deviation) between regions where the plastic material greatly expands and does not so much and such a plate thickness deviation becomes conspicuous in the lamp body portion
2
which is greatly expanded in particular. In other words, plate thicknesses ti and t2 in the peripheral edge portion
4
a
of the bulb fitting hole
4
provided in the lamp body portion
2
differ from each other in the peripheral direction (t1<t2).
When the bulb
5
is fitted into the bulb fitting hole
4
, furthermore, the presence of the plate thickness deviation makes compressive force acting on the gasket
7
on the thin-walled plate side smaller than what acts thereon on the thick-walled plate side, though compressive force acting thereon in the peripheral direction in any region remains constant when the plate thickness deviation is absent in the peripheral edge portion
4
a
of the bulb fitting hole
4
. Since the transverse cross section of the gasket
7
is such that the wall thickness of the gasket
7
is gradually reduced toward the inner peripheral side, the compressive force causes the gasket
7
on the thick-walled plate side to protrude in particular, which results in insufficient waterproofing.
SUMMARY OF THE INVENTION
An object of the present invention made in view of the foregoing problems pertaining to the conventional art is to provide a vehicle lamp which is fitted with a gasket capable of insuring that a bulb fitting hole is sealed even though the plate thickness of the peripheral edge portion of the bulb fitting hole varies in the peripheral direction.
Another object of the invention is to provide a gasket for fitting with a bulb fitting hole of a vehicle lamp, capable of sealing the bulb fitting hole even though the plate thickness of the peripheral edge portion of the bulb fitting hole varies in the peripheral direction.
In order to accomplish the object above, a vehicle lamp according to the invention includes a container-like lamp body, a front lens provided in the front opening of the lamp body, a bulb as a light source fitted into a bulb fitting hole formed in the lamp body, and a waterproofing annular gasket fitted in between a flange portion provided on the periphery of a bulb socket portion and the peripheral edge portion of the bulb fitting hole, the lamp body and the front lens being integrally formed by blow molding and is characterized in that the gasket has such a transverse cross section that a radial length is set greater than a length in the direction in which compressive force acts and that parallel convex portions extending annularly in the peripheral direction toward at least one of the flange portion side and the side of the peripheral edge portion of the bulb fitting hole are provided in the radial direction.
The gap between the flange portion and the peripheral edge portion of the bulb fitting hole is sealed by the gasket provided therebetween and the tight contact area among the gasket, the flange portion and the peripheral edge portion of the bulb fitting hole is increased because the gasket has a such a transverse section that the radial length is set greater than the length in the width direction (the direction in which the compressive force acts), so that the sealability of the gap between the flange portion and the bulb fitting hole is improved. Moreover, the plurality of parallel convex portions provided in the radial direction on the surface of the gasket and extending annularly surround the bulb fitting hole and act as those improving the sealability of the gap between the flange portion and the peripheral edge portion of the bulb fitting hole.
If the plate thickness in the peripheral edge portion of the bulb fitting hole varies in the peripheral direction, the compressive force acting on the gasket on the thick plate side becomes greater than what acts thereon on the thin plate side when the bulb (the socket portion) is fitted into the bulb fitting hole by bayonet engagement and this causes the force of protruding the gasket on the thick plate side outward in the radial direction. However, the gasket which is long sideways in the radial direction is hardly likely to be deformed outward in the radially direction even though the compressive force acts thereon and unlikely to protrude from the flange portion to that extent. Furthermore, the parallel convex portions provided in the radial direction of the gasket are pressed against the flange portion and/or the peripheral edge portion of the bulb fitting hole, and the pressure-welding force resists against the force of protruding the gasket outward and acts so as to force the gasket to remain inside the flange portion.
A vehicle lamp according to another aspect of the invention is such that the gasket has such a transverse cross section that the convex portion on the flange portion side is set opposite to the convex portion on the side of the peripheral edge portion of the bulb fitting hole and arcs of the same size are formed continuously in the radial direction.
By the convex portions on the flange portion side and the opposing convex portions on the side of the peripheral edge portion of the bulb fitting hole, a plurality of annular pressure-welding surfaces having strong pressure-welding force and surrounding the bulb fitting hole are concentrically formed between the gasket and the flange portion and between the gasket and the peripheral edge portion of the bulb fitting hole to insure that the gap between the flange portion and the peripheral edge portion of the bulb fitting hole is sealed.
Moreover, the pressure-welding force generated both between the gasket and the flange portion and between the gasket and the peripheral edge portion of the bulb fitting hole resists against the force of protruding the gasket outward in the radial direction and acting the gasket as accompanied with the plate thickness deviation of the peripheral edge portion
Goto Takayoshi
Nishitani Norihiro
Koito Manufacturing Co. Ltd.
Negron Ismael
Sember Thomas M.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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