Interpretation ID: nht91-3.31

DATE: April 29, 1991

FROM: George D. Powley -- Project Engineer, Truck-Lite Co., Inc.

TO: Paul Jackson Rice -- Chief Counsel, NHTSA

TITLE: Re FMVSS NO. 108 (Lamp, reflective devices, and associated equipment) Interpretation and/or petition for Orientation of electrical contact blades on sealed beam headlamps

ATTACHMT: Attached to letter dated 5-22-91 from Paul Jackson Rice to George D. Powley (A37; Std. 108)

TEXT:

We would like your advice regarding the orientation of electrical contact blades on sealed beam headlamps. We are contemplating the future production of a 2A1 type sealed beam with a contact blade orientation differing from that shown in SAE Standard J571, fig. 6 "type 2A sealed beam headlamp unit 4 x 6 1/2 in. (100 x 165 mm) rectangular unit" (Attachment A), which establishes a blade orientation that we will describe as being rotated 148 degrees 54' in the clockwise direction from the orientation established for a "type 2B sealed beam headlamp 142 x 200 mm" as shown in fig. 1 of SAE Standard J1132 (Attachment B).

We would like to produce both a large rectangular 2B1 and a small rectangular 2A1 using the same blade orientation. Specifically, we would propose to use the 2B1 orientation on the 2A1 unit. We wish to stress that the electrical function of each terminal in all cases would conform to the appropriate specification, and all the dimensional requirements, other than the "31 degrees 06' " orientation for the 2A1, would be adhered to on both products.

We do not feel that this proposed electrical contact orientation will in any way adversely effect the lamps performance or its ability to interchange with existing lamps in motor vehicles presently in the field.

We have observed that Koito Manufacturing Co., Ltd., of Japan is apparently presently marketing a 2A1 glass sealed beam unit with a non-standard blade orientation, and it is worthy of note that our proposed orientation differs from theirs only in that our terminal pattern would be rotated 180 degrees from theirs with respect to the top of the lamp.

We thank you for your prompt consideration of this matter. Should you have any questions, please contact the writer at (716) 665-6214 Extension 231.

Attachments

Attachment A

Figure 6 Type 2A Sealed Beam Headlamp Unit 4 x 6 1/2 in (100 x 165 mm) Rectangular Unit (Text and graphics omitted)

Attachment B

SAE Recommended Practice 142 x 200 mm Sealed Beam Headlamp Unit -- SAE J1132

Figure 1 Type 2B Sealed Beam Headlamp 142 x 200 mm (5.6 x 7.9 in) Rectangular Unit

(Text and graphics omitted)