Aimable vehicle headlamp assembly

A vehicle headlamp assembly is provided including a horizontal adjustment device for adjusting the position of a reflector, the adjustment device including a housing having an open bottom, a front wall and a rear wall, the front and rear walls having an aligned bore, the housing also having a top with a slot intersecting one of the walls, the wall intersected by the top slot having a horizontal slot adjacent the top slot greater than the top slot; a top gear having a head which is passable through the horizontal slot, the top gear also having a shaft slidable into the top slot; and a sleeve gear insertable through the housing bottom, the sleeve gear having a head for meshing engagement with the top gear, the sleeve gear having connected to the head a barrel body for supporting the head of the top gear.

FIELD OF THE INVENTION 
The field of the present invention is that of vehicle headlamp assemblies 
and more particularly adjustment mechanisms associated therewith. 
BACKGROUND OF THE INVENTION 
Vehicle headlamps require horizontal and vertical adjustment to meet U.S. 
government legal aiming regulations. Headlamps frequently use angled gear 
drive adjusters for aiming. 
Aiming is generally done with a simple tool or wrench by turning a screw or 
other similar device located behind the headlamp. Access to this area is 
important for without sufficient space to hand access, one cannot reach 
the adjuster in order to aim the headlamp. Right angle gear drives solve 
this problem as they need no rear access for adjustment. The drive shaft 
from the gear drive extends to the top of the headlamp for one to turn, 
which in turn moves the adjusting screw. The movement of the adjusting 
screw aims the headlamp. 
The above-noted gear drives generally consist of two helical gears that are 
held in an engaged position in a housing. Some of these housings have 
sonic welded caps that permit loading of the gears and internal bushings. 
The problem with previous gear drive adjusters is that their assembly 
involves a number of operations. The housing is designed to use several 
caps as covers over the pockets that contain the gears. The pockets are 
sealed when the caps are sonic welded to the housing, which can put the 
gears in a bind (if too tight) or result in a loose gear, which creates 
headlamp flutter, if improperly mounted to the housing. 
SUMMARY OF THE INVENTION 
The present invention provides a vehicle headlamp assembly permitting a 
simplified assembly of a right angle gear drive adjuster, eliminating the 
need for sonic welded caps for the adjuster. The present invention 
eliminates the need for extra parts (caps) and the need for their 
attachment (sonic welding and various other labor-consuming operations) to 
the housing, which reduces piece price of the component as well as 
diminishing the amount of polymers needed, thereby promoting the 
environment efficiency of the vehicle. 
These and other advantages of the present invention will be more apparent 
to those skilled in the art as the present invention is revealed in 
greater detail in the accompanying drawings and detailed description.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, the headlamp assembly 7 according to the present 
invention has a reflector housing 10 covered by a lens 12. The reflector 
housing has a surface (covered by the lens) which reflects a plurality of 
light beams from bulbs 14 (shown in phantom). The lens 12 then focuses 
these beams into a suitable pattern. Connecting the reflector housing 10 
to the vehicle (not shown) is an L-shaped bracket 16. Bracket 16 has a 
generally vertical arm 18 and a horizontal arm 20. Connected to the 
bracket 16 is a fixed pivot rod or shaft 22 having a ball end 24. A 
horizontal adjuster device 26 provides an adjuster body 28 and a shaft 30 
with a ball end 32. The bracket also includes a second adjuster device for 
adjusting the headlamp assembly in a horizontal plane. The second adjuster 
unit includes a shaft 36 with a ball end 38. 
Ball sockets 40 are fixably connected to the reflector and in turn are 
connected to the ball ends 24, 32 and 38 to mount the reflector housing 10 
to the vehicle. The beam emitted by the headlamp assembly 7 is adjusted in 
the vertical plane by the elongation or retraction of shaft 30, and the 
beam of the headlamp assembly 7 is adjusted in the horizontal plane by the 
extension or retraction of shaft 36. 
Referring additionally to FIGS. 2, 3 and 4, the horizontal adjustment 
device 34 utilizes the horizontal arm 20 as the housing. The housing has a 
T-shaped opening 42. The T shape of opening 42 is not required for 
functionality of the invention. However, it does make assembly easier. The 
housing of the adjustment device 34 has a first wall 44 and a second rear 
wall 46 which are spaced apart by a first dimension 48. The first and 
second walls have a generally aligned through bore 50. The horizontal 
bracket 20 also has a top 52 with a slot 54 with an extreme end 56 and a 
width 58 of a second dimension. The slot 54 intersects the rear wall 46. 
The rear wall 46 in an area closely adjacent to the top 52 has a slot 60 
with a third dimension 62 which is greater than the second dimension 58. 
Insertable within the slots 54 and 60 is a top gear 64. The top gear is 
fabricated from a zinc die cast. Top gear 64 has a bevelled head 66 with a 
flat 68. The head 66 has a diameter of a fourth dimension. Joined to the 
bevelled head is a shaft 70 having an end 72 generally opposite the head 
66 with a surface for receipt of torsional input from a wrench or socket. 
The top gear shaft 70 has a diameter of a fifth dimension closely 
approximate the second dimension and less than the fourth dimension. 
The head 66 of the top gear 64 is passable through the horizontal slot 60. 
In the assembly of the adjuster mechanism 34, the top gear 64 is first 
inserted through the slot 60 in rear wall 46, ideally to a point where the 
shaft 70 is contacted by the extreme end 56 of the slot 54. 
After placement of the top gear 64, a fiberglass-reinforced nylon sleeve 
gear 74 is inserted into the horizontal arm 20 via opening 42. Sleeve gear 
74 has a bevelled gear head 76 with a flat 78. Fixably connected to the 
sleeve gear 74 is a barrel body 80 which supports the top gear 64 in a 
position adjacent the top 52 and contacting the same. The sleeve gear head 
76 and barrel body 80 have a bore 82 with a diameter of a sixth dimension 
84. To allow the sleeve gear to capture the top gear in position, the 
shaft 36 is threadably inserted within the sleeve gear 74. The shaft 36 
has a diameter 86 of a seventh dimension greater than that of the sixth 
dimension so that the sleeve gear 74 will have an interference fit 
therewith. This interference fit may be modified by modifying portions of 
the bore 82 so that not all of the sleeve gear engages with the shaft 36. 
The sleeve gear 74 also has a lengthwise dimension roughly approximating 
that of the first dimension 48. 
In operation, after assembly of the parts, the top gear 64 is rotated, 
imparting rotation to the sleeve gear 74, thereby translating shaft 36 in 
a longitudinal fashion to horizontally adjust reflector body 10. Five to 
20 inches lbf of torque are required to effect adjustment. 
To control friction between the gears 64 and 74, the top gear 64 is limited 
toward the right by contact of shaft 70 with slot end 56 (FIG. 2) instead 
of the head 66 contacting a housing inner wall surface 57. To avoid 
flutter, the tolerance between length 48 and the length of the sleeve gear 
74 is held to .+-.0.05 mm. 
While this invention has been described in terms of a preferred embodiment 
thereof, it will be appreciated that other forms could readily be adapted 
by one skilled in the art. Accordingly, the scope of this invention is to 
be considered limited only by the following claims.