Arc tube and plastic reflector assembly method

A halogen bulb lamp assembly manufactured by mounting a previously aligned halogen bulb unit in a one-piece molded plastic rectangular reflector with a mirrorized paraboloidal inner surface. The halogen bulb unit has a pair of spaced connector pins that are coated with an epoxy adhesive and inserted into a pair of stepped through bores in the reflector. The pins are shaped to force epoxy uniformly into the larger portions of the reflector bores, and the ends of the pins project from the rear of the reflector and are spot welded to terminals that have barbed projections pressed into the rear of the reflector.

BACKGROUND OF THE INVENTION 
Vitreous glass sealed beam lamp units have been used for vehicle lighting 
since at least the 1930's in the United States. These lamps generally 
include a paraboloidal reflector having a highly mirrorized inner surface 
that usually has two central openings that receive connectors for a 
filament aligned within the reflector. The reflector is enclosed by a 
circular convex lens also constructed of glass that is located with 
respect to the reflector by various types of integral locating tabs and is 
joined to the reflector by heat fusion. The connector assemblies are also 
usually connected to the reflector by a heat fusion process, and the 
composition and pressure of gas within the reflector-lens envelope are 
carefully controlled through a filling tube formed integrally with the 
reflector, and this tube is fused after evacuation and/or, inert gas 
filling of the lamp envelope. Controlling the atmosphere within the 
envelope through the filling tube is extremely costly, and the filling 
tube must be carefully fused at the proper instant to achieve the desired 
atmosphere within the envelope. 
Such a sealed beam lamp unit is shown and described in the D. K. Right U.S. 
Pat. No. 2,147,314 dated Feb. 21, 1939. 
These sealed beam lamp units, which must be replaced after the filaments 
burn out, require complicated locking rings and adjustment assemblies, 
permanently carried by the associated vehicle to hold them in proper 
position. The locking rings frequently include adjusting brackets for 
varying the attitude of the lamp units to properly adjust the lamp's beam 
to effect the desired lamp alignment. 
It has been suggested that the reflector of a rectangular sealed beam lamp 
unit be constructed of a plastic material with support flanges formed 
integrally with the plastic to eliminate the complicated mounting flanges 
and rings required in prior lamp units. Such a construction is shown in 
the Thomas T. Talon et al U.S. Pat. No. 4,188,655. This patent discloses a 
lamp with three integral flanges on a plastic reflector that cooperate 
with three adjusting assemblies mounted to the vehicle that permit 
adjustment of the lamp beam in two orthogonal planes. While such an 
arrangement is suitable for many passenger automobile applications it is 
nevertheless quite costly because of the three separate fastening and 
adjusting mechanisms required. 
Another problem found in the manufacture of glass sealed beam lamp units is 
the difficulty in aligning the filament with the paraboloidal mirrorized 
reflector surface. Since the filament connector assembly is fused into the 
rear of the reflector, the fusion process itself frequently causes 
misalignment of the connector and the filament. Therefore, in sealed beam 
lamp units manufactured using this fusion technique it is necessary that 
the filaments be realigned after the fusion process has been completed. 
One attempt in the past to ameliorate this misalignment problem in 
vitreous glass lamp units has been to form the vitreous reflector with an 
enlarged opening in the rear and separately form a vitreous holder for the 
filament and connector assembly. The filament and connector assembly is 
then fused into the vitreous holder and the filament is aligned with 
respect to certain locating surfaces on the vitreous holder. Thereafter 
the holder and aligned filament are fused into the reflector. While this 
process has simplified the alignment of the filament it is also very 
costly because of the additional filament holder and the additional fusion 
of the holder to the reflector. 
A still further problem in these vitreous lamp units is the difficulty in 
attaching the terminals to the rear of the vitreous reflectors. Heat 
fusion of the terminals is difficult and exacerbates the connector 
misalignment problem. 
It is a primary object of the present invention to ameliorate the problems 
noted above in sealed beam lamp units. 
SUMMARY OF THE PRESENT INVENTION 
According to the present invention a halogen bulb lamp assembly is provided 
that has a molded plastic reflector and halogen bulb unit, that is far 
simpler to manufacture and less costly than prior known sealed beam lamp 
units of all types. Toward these ends, the halogen bulb lamp unit has 
connector pins with flanges that force epoxy adhesive uniformly around the 
ends of the pins in stepped mounting bores in the rear of the reflector 
and these flanges also locate the halogen bulb unit in the reflector as 
well as in a holder during alignment of the bulb. 
The connector pins are spot welded to halogen bulb leads and one of the 
pins carries a strap that surrounds and holds the vitreous portion of the 
halogen bulb. The bulb itself is conventional and commercially available 
from a variety of manufacturers. The connector pins are parallel and the 
flanges are spaced substantially from the distal ends of the pins. The 
leading or distal ends of these pins have a diameter sized to give an 
interference fit with the smallest diameter portions of the stepped 
mounting bores in the rear of the reflector. This interference fit 
provides two functions. The snug fit holds the halogen bulb unit in proper 
alignment while the epoxy adhesive in the bores cures and secondly it 
wipes excess epoxy from the connector pins as they pass out the rear side 
of the reflector so that a clean surface is presented for terminal 
attachment. 
Prior to assembly into the reflector, the halogen bulb unit subassembly is 
placed in an alignment fixture. This fixture has a pair of spaced holes 
that receive the ends of the connector pins and two sets of orthogonally 
aligned sight holes in the horizontal plane of the bulb's filament. The 
flanges on the connector pins accurately locate the pins in the fixture 
and the bulb is aligned by manually bending the pins until the filament is 
aligned in two transverse planes using the orthogonal sight holes. 
After removal of the bulb unit from the alignment fixture, a portion of the 
distal ends of the connector pins is coated with a suitable epoxy adhesive 
and the pins are simultaneously inserted into the stepped mounting bores 
in the rear of the reflector. As the pins are pushed into these mounting 
bores, the flanges on the pins act as a piston pressing and forcing the 
epoxy adhesive into the larger portions of the bores completely and 
uniformly filling the open areas between the pins and the bores. The 
assembly is then heated sufficiently to cure the epoxy adhesive. This 
method assures that the halogen bulb unit will be permanently maintained 
in an aligned position and effectively seals the reflector envelope. 
Terminals are electrically connected to the projecting ends of the 
connector pins and permit conventional vehicular electrical system 
connectors to be attached and detached quickly and easily. Each of these 
terminals has a tang portion insertable into the vehicular connector and 
an opening that receives the projecting end of connector pin. An L-shaped 
leg on the terminals extends in the same direction with and engages the 
lower surface of the pins and is spot welded thereto to assure good 
electrical contact. 
The terminals have a pair of integral spaced barbed ears that fit in 
grooves in the rear of the reflector flanking the connector pins to lock 
the terminals in position. These ears permit the terminals to be easily 
attached to the reflector prior to bulb unit attachment and they hold the 
terminals in position against the ends of the connector pins during the 
spot welding operation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings and particularly FIGS. 1 to 3, a rectangular 
sealed beam halogen lamp assembly 10 is illustrated generally including a 
one-piece plastic reflector 12 with a halogen bulb unit 13 mounted therein 
and enclosed by a vitreous glass or plastic rectangular lens 14. 
The reflector 12 is constructed entirely of a one-piece plastic molding of 
impact resistant plastic. One plastic that has been found to be 
particularly suitable is a polyester plastic "Petlon" manufactured by 
Mobay Chemical Company. This plastic is durable, shock resistant and also 
withstands a broad range of temperature variations. 
Plastic reflector 12 includes generally flat top and bottom walls 16 and 17 
having arcuate rear ends 18 and 19 connected together by a central 
paraboloidal wall 20. Interior surfaces 22 of walls 16, 17 and 20 are 
mirrorized by metallic vacuum deposition or other suitable process to 
provide the necessary reflective characteristics for the interior of the 
reflector to direct and focus light emitting from the halogen bulb 25 in 
bulb unit 13, forwardly along the geometric axis of the lamp unit through 
lens 14. 
The forward end of the reflector 12 has a rectangular lens receiving recess 
26 that is defined by outwardly extending integral wall 27, forwardly 
extending integral wall 28, and a rim 29 extending forwardly from walls 
16, 17 and 20. Walls 27, 28 and rim 29 extend peripherally completely 
around the reflector 12. The wall 28 defines part of recess 26 and also 
forms a hood or shield around lens 14 to protect the lens and limit stray 
light emission from the lamp in a direction perpendicular to the axis of 
the lamp. 
The lens 14 may be constructed of vitreous glass or plastic, either 
transparent or translucent, and is seen to have an outer peripheral rim 44 
having a beveled rear surface 45 and an inner corner recess 46 that fits 
over and seals against the end of projecting rim 29. The position of 
recess 46 locates rear surface 48 of the reflector spaced slightly from 
the bottom surface of recess 26 to form a pocket with the beveled wall 45 
in the recess for an epoxy adhesive 49 that extends all around recess 26. 
A mounting flange 32 is formed integrally with walls 27 and 28 and includes 
straight parallel top and bottom portions 33 and 34 connected by straight 
parallel side portions 36 and 37 as seen clearly in FIG. 1. The mounting 
flange 32 has molded apertures 38, 39, 40 and 41 that receive conventional 
threaded fasteners for holding the entire lamp assembly to an outer panel 
of the associated vehicle. 
As seen clearly in FIGS. 4 and 5, the halogen bulb unit 13 includes the 
halogen bulb 25 and a pair of identical spaced connector pins 52 and 53 
each having an annular flange 54 spaced considerably from distal or 
leading pin end 55 and defining a pin end portion 56. The pins 52 and 53 
are constructed of a suitable electrically conductive metal. 
The upper portion 58 of each pin is spot welded to outwardly bent halogen 
bulb leads 60 and 61. Pin 52 has a bracket strap 63 welded adjacent its 
upper end that surrounds halogen bulb reduced base portion 64 and holds it 
in a fixed position with respect to the connector pins 52 and 53. With 
this assembly, the connector pins 52 and 53 define both the support for 
the bulb 25 and the conductive paths relative thereto. 
The halogen bulb assembly 13 is optically aligned prior to assembly into 
the reflector 12. The filament 66 is aligned by properly spacing and 
aligning pins 52 and 53 and then bending bulb 25 until filament 66 is 
parallel to a plane extending through both pins 52 and 53 and is centered 
between the pins. To achieve this an alignment fixture 67 is provided that 
has a base 68 with spaced parallel bores 69 and 70 including enlarged 
upper counter-bores 72 that closely receive respectively the distal or 
leading pin portions 56 and the flanges 54. The flanges 54 serve as stops 
when seated in the counter-bores 72. 
The fixture 67 has opposed parallel planar walls 73 and 74 interconnected 
by perpendicularly related opposed parallel walls 75 and 76. Walls 73 and 
74 have aligned rectangular horizontal elongated sight apertures 79 and 80 
positioned at burner filament height level midway between the fixture 
bores 69 and 70, while walls 75 and 76 have aligned sight apertures 82 and 
83 positioned on the desired axis of the filament 66 parallel to a plane 
extending through the axes of pins 52 and 53. 
The reflector 12 has a rearwardly extending generally rectangular integral 
boss 85 as seen clearly in FIGS. 2 and 3. A pair of parallel aligned 
through bores 86 extend completely through boss 85 and are spaced apart 
the same distance as bores 69 and 70 in alignment fixture 67. As seen 
clearly in FIGS. 11, 12 and 13, the bores 86 are stepped including an 
upper counter-bore portion 88 that receives the connector pin flange 54, 
an upper enlarged cylindrical portion 89, an intermediate cylindrical 
portion 90 and a lower or outer reduced cylindrical portion 91. 
Cylindrical bore portion 91 has a diameter several thousandths of an inch 
smaller than the distal pin portion 56 so that there is an interference 
fit as the pin portion 56 is pushed through the reduced bore portion 91. 
Connector terminals 95 are initially attached to the reflector 12. As seen 
clearly in FIGS. 9, 11 and 14, each of the terminals 95 is identical and 
includes a flat tang portion 97 with a rectangular opening 98a having an 
L-shaped tab 98 extending therein as seen in FIG. 12. Tab 98 has a portion 
parallel to and engageable with the bottom lower portion of the distal 
ends 93 of the connector pins 52 and 53 after they are attached to the 
reflector 12. Terminals 95 also have inwardly turned barbed ears 100 and 
101 as seen in FIGS. 11 and 14 that have a width slightly greater than the 
width of grooves 103 molded in the rear surface of reflector boss 85. 
There are a pair of grooves 103 adjacent and flanking each of the 
reflector bores 86. The terminals 95 are pressed into the reflector 12 
with the barbed ears 101 pushed into the interfering reflector grooves 
103. 
To effect alignment, the burner assembly 13 is placed in the fixture 67 by 
inserting lower rod portions 56 until flanges 54 are seated in 
counter-bore 72 and during this process the connecter pins are bent into 
parallelism with the flanges 54 of the pins being aligned in the same 
plane. Thereafter the pins are manually bent until the filament 66 is in 
optical alignment with the sight apertures 82 ad 83 in the plane of FIG. 
7. Then using the line of sight apertures 79 and 80 the pins are bent in 
the plane of FIG. 8 centering the filament 66 midway between the bores 69 
and 70. The aligned halogen bulb unit is then removed from the alignment 
fixture 67. 
After the halogen bulb unit 13 is removed from the alignment fixture 67, an 
epoxy adhesive 92 is applied around the distal pin portion 56 of each pin 
spaced a short distance from pin end 55 as seen clearly in FIG. 13. The 
coated pins 52 and 53 carrying the halogen bulb unit are inserted into the 
bores 86 in the reflector 12. The terminals 95 have already been pressed 
into the rear of the reflector boss 85 and as the forward-most or distal 
"clean" portions 93 of the pins are pressed through reduced bore portion 
91, the reduced bore portions begin wiping the epoxy from the pin portions 
56 and pushing epoxy upwardly relatively to the pins toward the 
approaching pin flanges 54. In this way the reduced bore portions 91 clean 
epoxy adhesive from the portions of the pins projecting from the reflector 
as seen in FIG. 12 in engagement with terminal tabs 98, so that the 
terminals 95 may be welded thereto without further cleaning. The snug fit 
of the bores portions 91 with the pin portions 56 also serves to hold the 
entire bulb assembly 13 in an aligned position while the epoxy adhesive 92 
is curing. 
With continued movement of the pins into and through the bores 86, the pin 
flanges 54 as they approach bottoming in the counterbores 88, will engage 
the upper part of the epoxy adhesive 92 and act is pistons forcing epoxy 
uniformly throughout the enlarged intermediate bore portions 89 and 90 
completely around the pin portions 56 thereby creating not only a good 
sealing bond but assuring accurate, secure alignment of the halogen bulb 
unit 13 in the reflector 12. After the flanges 54 hit the bottoms of the 
reflector counter-bores 88 the bulb unit 13 is correctly positioned in the 
reflector 12. 
The tab 98 of each of the terminals is spot welded to the projecting and 
engaging pin portion 93. In this way the enlarged interfering barbed ears 
101 hold the terminals securely in position while the connector pins are 
being spot welded thereto without any additional holding fixture or 
support, and of course they continue to firmly hold the terminals to the 
reflector after welding. 
The lens 14 is then attached with epoxy 49 to the reflector recess 26 and 
the assembly is baked for approximately 90 minutes at 320 degrees 
Fahrenheit to cure the epoxy adhesive around pins 52 and 53 as well as 
around the lens 14. Subsequent to baking, a vent hole, not shown in the 
drawing, in the rear of the reflector 12, is sealed with a vent plug as 
shown and described fully in our copending application Ser. No. 376,619, 
filed May 10, 1982, assigned to the assignee of the present invention.