Interpretation ID: nht76-4.48

DATE: 05/18/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: NSK Warner Kabushiki Kaisha

TITLE: FMVSS INTERPRETATION

TEXT: This responds to NSK Warner's April 12, 1976, question whether the release and buckle requirements of Standard No. 208, Occupant Crash Protection, and Standard No. 209, Seat Belt Assemblies, permit the use of a latch mechanism that consists of a fixed hook over which belt webbing (presumably from the upper torso and pelvic portions of a continuous loop system) is slipped by the occupant, causing a rotating catch to close the open end of the hook and secure the webbing. Release is accomplished by depression of a push button that rotates the catch away from the open end of the hook, followed by occupant action to slip the belt webbing off the hook.

Standard No. 208 specifies that a seat belt assembly installed in a motor vehicle shall have a latch mechanism "[that] releases at a single point by a push-button action" (S7.2(c)). "Release" in this context means that the portions of the belt assembly on either side of the latch mechanism disengage from one another. From your description of the hook mechanism, it would not disengage the two portions of belt assembly by a push-button action, because an additional action by the occupant is required. It therefore appears that such a mechanism would not conform to S7.2(c) of Standard No. 208.

Standard No. 209 specifies that "A Type 1 or Type 2 seat belt assembly shall be provided with a buckle or buckles readily accessible to the occupant to permit his easy and rapid removal from the assembly" (S4.1(e)). "Buckle" is defined in S4 as "a quick release connector which fastens a person in a seat belt assembly." Section S4.3 further specifies that "The buckle of a Type 1 or Type 2 seat belt assembly shall release when a force of not more than 30 pounds or 14 kilograms is applied" (S4.3(d) (1)). "Release" in this standard is also interpreted to mean that the portions of the belt assembly on either side of the latch mechanism disengage from one another. For this reason, it appears that the described device would not comply with the listed requirements of Standard No. 209.

I trust that this answer is responsive to your inquiry.

SINCERELY,

NSK WARNER KABUSHIKI KAISHA

April 12, 1976

Francis Armstrong Director Office of Standard Enforcement Motor Vehicle Programs U.S. Department of Transportation National Highway Traffic Safety Administration Re Interpretation of "buckle" for seat belt

One of our customers has developed a kind of latching device for seat belt buckle. We are obliged if you will read followings and give your opinion to us.

Structure

As illustrated in the attached sheet, the device books like a hook with a stopper and it has an arm fixed stationary to a base, a rotatable c shape catch and a pushbutton.

If a thin and not so soft article such as plastic-covered webbing enters into a slot between the arm and the base, the article pushes the right claw of the catch (Fig. 1) and rotates it. Then, the left claw of the catch shuts the entrance of the slot (Fig. 2).

Pushing the button makes the entrance open by using a mechanical linkage.

Our doubt

We have no doubt of its mechanism but there is a doubt raised after consideration of requirements of FMVSS 208 and 209 if this device should be used for the seat belt buckle.

When a passenger pushes the button and opens the entrance of the slot to release himself from a seat belt restraint, the webbing remains in the slot and it does not make him free. The device, therefor, needs one more action; "picking the webbing off the device", to release the passenger completely.

Especially in a case after a turn-over accident, we may be unable to release the passenger because the seat belt is under tension caused by his weight if the webbing has been caught by the hook.

The above is our anxiety about introducing the device to the seat belt buckle.

We would appreciate very much if you could judge and let us know whether the device could be regarded as a buckle.

A. Mita, Chief Engineering Dept.

Fig. 1 Released Position

(Graphic omitted)