Interpretation ID: nht71-5.52
DATE: 06/25/71
FROM: AUTHOR UNAVAILABLE; Lawrence R. Schneider; NHTSA
TO: Robert W. Hunt Company
TITLE: FMVSS INTERPRETATION
TEXT: By letter of May 26, 1971, you requested an interpretation of the newly issued S5.3 of Standard No. 209, Seat Belt Assemblies (36 F.R. 4607, March 10, 1971). Your question is whether the three-pound weight shown in Figure 9 is the only force permitted on the lengthening stroke of the buckle abrasion test, or whether additional force may be applied.
The three-pound weight is shown in the illustration of the lengthening stroke in Figure 9 for reasons of pictorial accuracy, since it remains attached to the belt throughout the cycle. It is not intended to indicate a three-pound limit on the lengthening stroke force and you are correct in your understanding that additional tension may be applied to obtain the required eight-inch stroke length.
Please advise if we can be of further assistance.
ROBERT W. HUNT COMPANY May 26, 1971
National Highway Traffic Safety Administration
Attention: L. Schneider
Re: Amendment to Federal Motor Vehicle Standard No. 209, Paragraphs 571.21, Title 49 of CFR Docket 69-23, Notice 2
When making tests provided for in the addition (d) "Resistance to Buckle Abrasion" of Paragraph S5.3, a condition occurred which led us to request clarification of the intent of this test procedure.
Figure 9 provides for a three-pound weight (B) and it could be interpreted that this weight alone is required to pull the webbing through on the lengthening stroke. It is our understanding that this is not the intention of the specification and that the three-pound weight is provided to offer resistance on the shortening stroke and that additional tension may be applied on the lengthening stroke to be certain that the webbing is pulled through the buckle to obtain a stroke length of 8".
In view of what we consider to be more than one possible interpretation of the intent of the specification we will appreciate clarification.
W. H. SAVAGE, P.E. President