Development of a Buckle Release Test Procedure 2004-01-0472

There are many factors that must be considered when designing a restraint system. The way the components function as a system and the design of the system's components are among these factors. While there are several tests required by the US Federal Motor Vehicle Safety Standards, not all factors are addressed.

This paper will address the resistance of a seat belt buckle to accidental or inadvertent release. The test procedure deals with the design of the buckle only and does not consider other important factors such as placement or shielding. There have been numerous reports where occupants are found unrestrained following a crash even though evidence, such as witness statements, use and custom or clear physical findings, indicates the occupant was belted. It is believed by many that some of these cases are the result of inadvertent buckle release. Such a release occurred during a test program conducted and was the result of contact to the buckle release button by the arm of the test dummy. Similar results have been reported by other researchers and test facilities. The test procedure included in this paper was developed to assess the ability of a buckle to remain engaged when subject to the application of a sphere to the release button as discussed in the European standards. It is hypothesized that the more difficult it is to actuate the buckle release mechanism with the sphere, the less likely it will inadvertently release in a crash. The ability of a buckle to remain latched unless deliberately released is a basic and fundamental requirement of good restraint system design.

The paper will present the test procedure as well as test results from a sample test program conducted by the authors.