| Abstract | It has been noted that many people when changing headlamps assume that because the original headlamp was properly aimed, the replacement will also be aimed properly if the headlamp aiming adjustments were not altered during replacement. For SAE headlamps, the photometric aim relative to the aiming plane is controlled during manufacture. For installation in a vehicle the aiming plane is then used as a reference by mechanical aiming devices. When changing headlamps the only physical reference points are the seating pads which form the seating plane, so the relationship between the seating plane and the aiming plane of the original and replacement lamps determines the change in aim of the replacement lamp.
Accordingly, as an adjunct to the photometric scan measurements being carried out on market samples of headlamps (references 9, 10 & 11), a suitable jig was constructed to permit measurements to determine the angular deviation between the aiming and seating planes for these headlamps.
This report describes and tabulates the measurements and results on ninety-three headlamps having NAE sample numbers ranging from 206 to 302. The results obtained from similar measurements on earlier sampled SAE headlamps [LTR-ST.695 (NAE Nos.141-162) and LTR-ST.749 (NAE Nos. 181 to 205), References 7 and 8 respectively] are included in Appendix A. |
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