Interpretation ID: nht81-3.10

DATE: 08/25/81

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Ford Motor Company

TITLE: FMVSS INTERPRETATION

TEXT:

AUG 25 1981 NOA-30

Roger E. Maugh, Director Automotive Safety Office Environmental and Safety Engineering Staff Ford Motor Company The American Road Dearborn Michigan 48121

Dear Mr. Maugh:

This responds to your letter of July 31, 1981, to Hugh Oates of my staff requesting an interpretation concerning Safety Standard No. 210, Seat Belt Assembly Anchorages. You ask whether you are correct in your belief that the requirements of paragraph S4.3.1.1 of the standard apply to the seat belt anchorages used in your planned 1982-model Continental passenger cars rather than the requirements of paragraph S4.3.1.2.

Paragraph S4.3.1 of the Standard specifies location requirements for the seat belt anchorages for Type 1 seat belt assemblies and the pelvic portion of Type 2 seat belt assemblies. Paragraph S4.3.1.1 applies in those installations in which the seat belt does not bear upon the seat frame, and the requirements of paragraph S4.3.1.2 apply in installations in which the seat belt does bear upon the seat frame. On the 1982 Continental passenger cars, the buckle end of the seat belt assembly passes through a "console support structure" which is connected to the bottom of the seat frame. However, you contend that since the console support structure is not a structural component of the seat frame, the seat belt does not bear upon the seat frame and, consequently, that paragraph S4.3.1.1 applies.

Your interpretation of paragraphs S4.3.1.1 and S4.3.1.2 is correct. The phrase "bears upon the seat frame" as used in paragraph S4.3.1.2 refers to seat belt assemblies in which the seat belt presses or rests directly on the main structural frame of the seat. As illustrated in the photographs supplied in your letter, the seat belt in the 1982-model Continental passenger cars does not bear upon the structural seat frame. Rather, the belt rests on the console support frame which is not a necessary structural component of the main seat frame, but is merely attached to the seat frame at the bottom on the inboard side. Since the seat belt is located to the side of the seat frame and does not bear upon the structural seat frame itself, the requirements of paragraph S4.3.1.1 apply to the location of the seat belt anchorages used in the 1982 Continental passenger cars rather than the requirements of Paragraph S4.3.1.2.

We note that the console support frame could easily have been attached to the transmission tunnel rather than to the seat frame. In that case, the seat belt obviously would not bear upon the seat frame. However, with such a design, the frame supporting the belt would not move with the seat, and the driver could have problems reaching the belt and positioning it properly when the seat is in certain positions. The design of the passenger seat and seat belt assembly in the 1982 Continental is very desirable because attachment of the console support frame to the seat makes the seat belt very accessible in all seat positions. The fact that the console was attached to the seat frame for convenience purposes does not mean that the console is part of the seat frame within the meaning of S4.3.1.2.

The original intent of the location requirements of FMVSS 210 was to enhance belt performance with acceptable belt comfort and convenience. The specific requirements that are the subject of this interpretation were intended to ensure that belts would not develop excessive slack if a seat structural member bent or failed during a crash, and to reduce the likelihood that the lap belt would move into the abdominal area during a crash. We trust that Ford has adequately tested the configuration that is proposed here to ensure proper performance in a crash situation.

Please contact this office if you have further questions.

Sincerely,

Frank Berndt Chief Counsel

July 31, 1981

Hugh F. Oates, Jr., Esq. Office of Chief Counsel National Highway Traffic Safety Administration 400 Seventh Street, S. W. Washington, D. C. 20590

Dear Mr. Oates:

This letter is to request concurrence in Ford Motor Company's view that compliance to section S4.3 "Location" of Motor Vehicle Safety Standard No. 210 properly should be evaluated under subsection S4.3.1.1 for passenger seats of a new design being introduced in 1982 model Continental passenger cars. The applicability of subsection S4.3.1.1, rather than subsection S4.3.1.2, of Standard No. 210 was discussed between Ford personnel and you and Mr. R. Hitchcock of the Administration in Dearborn yesterday. At that time you were shown the new seat design and told why we believe it presents the possibility that a compliance tester might erroneously conclude that it should be evaluated against the criteria of subsection S4.3.1.2. If anchorage locations of these vehicles were to be evaluated under that subsection, rather than subsection S4.3.1.1, the location specifications could not be met.

The potential for misunderstanding arises, we believe, out of the fact that the bottom of the seat frame has connected to its inboard side a console support structure through which the inboard (buckle) end of the seat belt assembly passes. The console support structure is intended to provide a base for a "mini-console" that is to be installed on the inboard side of each half of a split bench seat. It is not a structural member of the seat frame and therefore, in our opinion, the fact that the inboard end of the belt would bear on the structure of the console support should not result in the anchorage locations being evaluated under the criteria of subsection S4.3.1.2 which apply only to installations in which the "...belt bears upon the seat frame...".

As may be seen from sketches provided by the Administration to contractors evaluating compliance to Standard No. 210 (Attachment A), the routing of the seat belts contemplated by the drafters of the standard as "bearing upon the seat frame" involve configurations wholly unlike that in question. Moreover, routing the inboard end of the seat belt assembly through a console support structure that moves with the seat frame has the salutary effect of helping to best position the belt and improving belt accessibility, no matter what position the seat is adjusted to. Ford could obviate all risk of misapplication of subsection S4.3.1.2 to the new seat design by physically modifying the console support so that the inboard end of the seat belt would not bear upon its structure, but only on the trim cover. For the reasons discussed above, we respectfully submit that we should not be required to do so.

Furnished for your reference are Attachment B which depicts the lower seat frame for the 1982 Continental, Attachment C, the console support and its cover, Attachment D, the untrimmed console support attached to the seat frame, and Attachment E, a finished seat assembly.

In order to avoid needless misunderstanding about the compliance of these seat belt assemblies to the anchorage location provisions of Standard No. 210 after production commences in mid-August, I should appreciate receiving the Administration's prompt confirmation of our analysis of the applicability of subsection S4.3.1.1 to the newly designed seat and console assembly, or your expression of any grounds on which the Administration may disagree with that analysis. Sincerely

Roger E. Maugh

Attachments