Personal InjurySeat Belt Buckle Evolution
The object of a seat belt buckle is to bring two ends of the seat belt together in a junction which will keep the two ends of the belt securely fastened to one another, particularly during the sudden and severe loads imposed during an accident - yet be easy for the occupant to fasten and unfasten in entering and existing the vehicle.
The first seat belt to be mass-produced for this purpose in American vehicles in the 1950's and early 1960's closely resembled the type of widely-recognized seat belt buckle still in use on Airliners today, called a "lift-cover" buckle. The restraint system would have a male tongue at one end with a hole or aperture in it, and would be inserted into the female buckle where a spring-loaded latch pin (called a pawl) would pass into the pawl and hold the tongue firmly into the buckle. The pin would be extracted when the user lifted up the hinged, spring-loaded buckle cover, releasing the pawl from the aperture in the tongue, allowing the tongue and buckle once again to separate.
Early after installation of these buckles, concern arose that the lift-cover could be accidentally dislodged by the occupant's motions inside the vehicle, leaving the user unrestrained in an accident.
In 1965, General Motors Corporation employee, Robert C. Fisher designed a buckle which operated similarly as the lift-cover buckle, but substituted a protected button on the side of the buckle for the lift-cover. This was the first major "side-release" or "top-release" style buckle used on American vehicles. The spring-loaded button would cause the pawl to span into the aperture when the tongue was fully inserted all of the way into the buckle. When the occupant wanted to disengage the tongue and buckle, (s)he would press the button and the pawl with be pushed out of the tongue's aperture, permitting separation of the tongue and buckle. The first of Fisher's designs was patented in 1965, and was called the RCF-65 ("RCF" standing for Robert C. Fisher) or "Maxi-Buckle."
In 1967, Fisher patented a smaller side-release buckle which operated identically to the RCF-65, which differed from the "Maxi-Buckle" only in respect to its miniaturization. This buckle became known as the "RCF-67" side-release buckle (also known as the Type I buckle in General Motors Vehicles). It remains the most numerous buckle installed in American vehicles to date. At the time of its initial conception, the RCF-67 was lightweight, simple in design, easy to manufacture, had few moving parts, was fairly durable, and therefore was relatively inexpensive to manufacture. It therefore became immediately popular with American automakers whom the government involuntarily compelled to make seat belts mandatory equipment in U.S. cars beginning in 1968.
In the early 1980's the American automakers and their buckle suppliers began a campaign to develop a set belt buckle with a tongue eject feature and a release push button on the end of the buckle, rather than on the side or top.
The initial generation of these tongue-eject feature buckles were side-release buckles. The first of these tongue-eject buckles used in production was manufactured by Hamill, a Division of Firestone (now TRW Vehicle Safety Systems) and was used as early as 1973 and 1974 Ford vehicles. Called a "diecast" buckle, the buckle looked remarkably similar to the RCF-67, but was made by Hamill pursuant to a Swiss patent which announced as its sole purpose, prevention of the danger of "false latching." This is discussed in further detail below. After two years, Ford went back to the RCF-67 solely to save money on the production costs of the buckle.
However, in the early 1980's both Ford and General Motors once again directed their buckle suppliers to develop a new end-release buckle with a tongue eject feature. In the late 1980's the Ford Taurus and Lincoln Sable utilized side-release buckles with tongue eject features, as did the Ford Probe. At the same time, TRW VSSI (which had purchased Hammill from Firestone several years earlier) developed a buckle with a German Company called REPA, which was the first of the major "end-release" tongue-eject feature buckles ultimately to be developed for use in the United States.
The REPA end-release buckle had the release button placed on the end of the buckle (next to the insertion point of the tongue), instead of on the top or side of the buckle. The tongue-eject feature prevented false latching, while locating he release button on the end of the buckle prevented a side-load from inadvertently causing the release button to be activated, thus also preventing inertial unlatching, as discussed below.
TRW VSSI and Allied Signal both developed end-release buckles for use in Ford and GM vehicles in the late 1980s. Today, the end-release buckles is the predominant buckle sold in the United States, and the number of new vehicles being equipped with RCF-67 buckles continues to diminish.
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