nht78-3.20 | NHTSA

DATE: 08/18/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Alfa Romeo, Inc.

TITLE: FMVSS INTERPRETATION

ATTACHMT: ATTACHED TO LETTER DATED 10/13/88 TO PAUL UTANS FROM ERIKA Z JONES, REDBOOK A32 STANDARD 208, STANDARD 210; LETTER DATED 08/11/88 TO ERIKA Z JONES FROM PAUL UTANS, OCC - 2405; LETTER DATED 12/01/86 TO FRANCOIS LOUIS FROM ERIKA Z JONES, STANDARD 208

TEXT: This responds to your recent letter concerning Alfa Romeo's proposed designs for Type 2 seat belt assemblies to be used on convertibles. You ask for clarification of the anchorage location requirements specified in Safety Standard No. 210, as they would apply to your proposed designs.

Paragraph S4.1.1 of Safety Standard No. 210, Seat Belt Assembly Anchorages, specifies that anchorages for a Type 2 belt shall be installed for each forward-facing outboard designated seating position in passenger cars other than convertibles. Manufacturers are permitted to install Type 2 belts in convertibles, however, under paragraph S4.1.2 of the standard which specifies that either a Type 1 or Type 2 belt may be installed for designated seating positions not required to have Type 2 belts under the previous section.

Since convertibles are only required to have Type 1 belts, only the pelvic portion of your proposed Type 2 designs must meet the anchorage location requirements of the standard. These location requirements are specified in S4.3.1, and the pelvic portion of your two proposed designs (Figures 2 and 3 in your letter) appear to fall within the 20 degrees - 75 degrees acceptable range. The upper torso portions of the belt designs do not have to comply with the 40 degrees acceptable range specified in S4.3.2, since those portions are in addition to what is required by the standard.

In response to your general question, "seat belt anchorage" is defined in Standard No. 210 as the "provision for transferring seat belt assembly loads to the vehicle structure." For purposes of determining compliance with the anchorage location requirements of the standard, the agency interprets anchorage to include any load-bearing element of the seat belt assembly that is capable of meeting the force requirements of Standard No. 210. For example, in your Figure 1 you state that the lap belt is anchored "at point 'C' within the 40 degrees zone and then passes through a webbing guide anchorage." The 40 degrees zone is not the applicable location requirement for lap belts and if this were the only anchorage, the belt would not comply with the standard. However, since the "webbing guide anchorage" appears to be within the applicable 20 degrees-75 degrees zone, the belt would be in compliance if that anchorage is capable of meeting the force requirements of the standard. The agency considers an assembly to be in compliance if there is one force-complying anchorage within the acceptable ranges specified in the standard, and that anchorage is determinative of the angle the belt crosses the vehicle occupant.

To summarize, both of your proposed Type 2 seat belt assemblies would comply with the location requirements of Standard No. 210 if used in convertibles, since only the pelvic portions of the assemblies would have to meet the requirements of the standard and the anchorages for those portions appear to be within the acceptable ranges. Further, either assembly design can be used in hard-top automobiles if it has one anchorage capable of meeting the force requirements of the standard that is located in the 40 degrees acceptable range for upper torso portions of Type 2 belts.

Please contact Hugh Oates of this office if you have any further questions concerning this subject (202-426-2992).

Sincerely,

Alfa Romeo, Inc.

May 12, 1978

Joseph J. Levin, Jr. Office of Chief Council U.S. Department of Transportation National Highway Traffic Safety Administration

RE: LOCATION OF ANCHORAGE FOR UPPER TORSO RESTRAINT REQUEST FOR CLARIFICATION

Dear Mr. Levin:

Due to recent changes in European law, the upper torso restraint anchor on the Alfa Romeo Spider (roadster) will have to be redesigned. Ideally, an upper torso restraint anchor that complies with both U.S.D.O.T. F.M.V.S.S. and European law in one common design is preferred.

To keep this request brief, we prefer to use graphic references:

DRAWING 1: (Figure 1)

This depicts presently produced U.S. model (115.41) Spider having a "type 1" belt assembly. This lap belt is anchored at point "C" within the 40 degrees zone and then passes through a webbing guide anchorage at outboard points and "B".

Unfortunately this system will not comply with the new European law. Therefore, we consider two alternate substitute designs described below.

DRAWING 2: (Figure 2)

This shows a proposed installation of a "type 2" (3 point) torso/lap harness. Here we see the retractor mounted on the floor (outside the 40 degrees zone) at point 4. The webbing is then fed through a guide anchorage at point 3 (within the 40 degrees zone) up to another webbing guide on the seatback at point 1.

In this proposal, while the retractor is outside the 40 degrees zone, the "anchorage guides" 3 and 1 are well within the acceptable zone. This poses the question as to what is the "anchorage" (i.e., the retractor or the "anchor"?). In mechanical theory the retractor could be outside the 40 degrees zone while the "anchorage" remained within the 40 degrees zone. Our view is that the intent of N.H.T.S.A.'s design limitation is to prevent the torso webbing from attaining a loadline of more than 40 degrees (for well known reasons). This proposal achieves the "intent" of the author of F.M.V.S.S. 210, even though in a "roundabout" manner.

We would like N.H.T.S.A.'s opinion as to whether or not this proposal demonstrates compliance with 210's "40 degrees Fig. 1 zone" by design.

DRAWING 3: (Figure 3)

This proposed design eliminates the point 3 roller of the previous design, for simplicity. Instead, the retractor is mounted "direct" but slightly outside the 40 degrees zone.

Now, at point 1 on the seatback, this guide is well within the acceptable zone. It is in reality the point that determines the position of the webbing in relation to the occupant's torso. (This point is referred to as the "effective point" in the European law. It is the last point at where the webbing changes direction).

Needless to say, the point 1 guide does have sufficient load bearing capability to consider it as an anchorage. It is not merely a "convenience loop" as used on some U.S. vehicles, but an integrally designed part of the seat back.

F.M.V.S.S. 210 S4.1.1

This requirement specifically states that anchorages for Type 2 belt assemblies "shall be installed . . . . . in passenger cars other than convertibles." Does this by exclusion ("shall - other than convertibles") prohibit the installation of Type 2 belt assemblies in convertibles - or does it infer Type 2 as an option?

If the Type 2 is prohibited in convertibles, then we must try and define the word "convertible." What determines "convertibility" and what are we "converting" (the top?). If we are "converting" from a closed to an open vehicle, when and what degree of "open-ness" determines that the vehicle is in fact "open" or a convertible. We feel this is academic and use it only as a means to demonstrate the vagaries of F.M.V.S.S. 210 requirements. We realize that we also are among the minority by virtue of our almost exclusive production of "convertibles".

Our design management would appreciate N.H.T.S.A.'s legal opinion as to the compliance capabilities of our proposals 2 and 3 as soon as is possible as we are delaying tooling pending your decision.

Should the enclosed drawings require clarification or further discussion, please let us know.

D. Black Manager U.S. Engineering Office

cc: ING. FOGLIATA -- DIPRE/LEGO ING. DIMORA -- DIPRE/CARR DIPRE/ESPE ESCA

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(Illegible Word) Present location SEAT BELT ANCHORAGES A-B-C SEAT BELT TYPE "1" PRESENT No DISEGNO Legn 115L1 ed 79 fg1

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Interpretation ID: nht78-3.20