Interpretation ID: nht89-2.91

TYPE: INTERPRETATION-NHTSA

DATE: AUGUST 31, 1989

FROM: J. BRETTSCHNEIDER -- ROBERT BOSCH GMBH

TO: RICHARD VAN IDERSTINE -- DOCKET SECTION, NHTSA

TITLE: PERFORMANCE OF THE IMPACT TEST ACCORDING SAE J1383

ATTACHMT: ATTACHED TO LETTER DATED 3-29-90 TO J. BRETTSCHNEIDER, ROBERT BOSCH GMBH, FROM STEPHEN P. WOOD, NHTSA.

TEXT:

According to the above-mentioned SAE Standard (recommended practice), Section 4.10.3, the impact test has to be performed ... along the mechanical axis ...

SAE Standard J 579, Section 2.14 defines the mechanical axis as ... perpendicular to the aiming plane through the geometric center of the lens.

Now the questions arise

- where is the geometric center of a lens without aiming pads?

- where is the geometric center of a lens which moreover covers two compartments, one for the lower beam and one for the upper beam?

Please give us your advice.

Thanking you in advance.