Interpretation ID: nht88-3.32

TYPE: INTERPRETATION-NHTSA

DATE: 09/02/88

FROM: R. YAMAUCHI -- NIPPON SEIKO K K

TO: NHTSA OFFICE OF VEHICLE SAFETY COMPLIANCE ENFORCEMENT

TITLE: DUAL MODE RETRACTOR (ELR MODE AND ALR MODE RETRACTOR)

ATTACHMT: ATTACHED TO LETTER DATED 06/19/88 FROM STEPHEN P. WOOD -- NHTSA TO R. YAMAUCHI; REDBOOK A33; INTERP 209

TEXT: The above retractor is an ELR which can change to ALR mode in order to fasten child seat.

Seat belt webbing of the dual mode retractor is pulled out to 100% extension position, where ELR mode changes to ALR mode. The ALR mode returns to ELR mode after specified amount of webbing is retracted. In ordinary use, that is webbing is not pulled o ut completely, ELR mode does not change and webbing moves smoothly without locking due to ALR mode.

We believe this dual mode retractor should be treated as ELR because ALR mode is voluntary act. Dual mode retractor, therefore, has to meet ELR performance requirement, and does not have to meet ALR performance requirement.

FMVSS 209 paragraph S5.2(k) specifies as follows. "---- An emergency locking retractor or a nonlocking retractor attached to upper torso restraint shall be subjected to 45,000 additional cycles of webbing withdrawal and retraction between 50 and 100 per cent extension. ----" If the dual mose retractor may be treated as ELR, the above testing will be applied. However, there is a problem. After webbing is fully pulled out, webbing locks at the above 50% extension position due to ALR mode. (In this case, the mode does not change to ELR unless much more amount of webbing is retracted.) To stop the webbing withdrawal just before the fully pulled out position might be able to prevent the change to ALR mode. But it will be in vain because 9 Kg load at that position will extend the webbing to the 100% extended position.

Retractor durability testing of the dual mode retractor can be conducted between 100% extended position and any ELR mode position, where more than specified amount has been retracted. As a test for this retractor, we request cycles of webbing withdrawal and retraction between 0 and 100% extension. We think this test cause no problem because requirement of S5.2(k) is less strict than that of this cycle test.

Please answer the following questions.

Q1 - Is dual mode retractor regarded as ELR? If so, is only the ELR requirement required?

Q2 - We requested 45,000 cycle test after dust should be conducted between 0 and 100% extension length. Is this correct? If not, how do we test the retractor.

We would appreciate if you would answer our questions.

Very truly yours,