UPDATE: Thanks to Rob, we now have an “in-the-wild” photo of the slotted Free-Lock hub. I’ve also updated the post to indicate there were four slightly different designs and an additional patent that we’ve documented.
In 1952, Aurthur Warn filed a patent for an adjustable clutch front hub that would allow jeep owners to engage and disengage their front axles in and out of four wheel drive. Warn was awarded a patent for his work in July of 1954.
The problem with these Warn hubs was that the clutch design was complex. With this in mind, a company called the Free-Lock Corporation developed an alternative hub. In December of 1954, only six months after Warn patented his hub, Rex Requa submitted his design to the patent office.
We have yet to document this exact design on a jeep. The reason for this might be because the face of the final hub may look different than the design shown in the patent. Perhaps Free-Lock found that in practice users needed a tool to switch the hubs in and out. However it happened, soon the first Free-Lock hub was born. It probably began selling in 1955.
It seems plausible that the main driver behind the hub was James R. Lloyd. In April of 1956 he received a copyright for the term “One million 4 wheel drive vehicles need Free-Lock hubs”. Later in the year he received a second copyright, “The world’s finest and safest, Free-Lock hubs”. (View both copyrights here)
1. The 1-screw Free-Lock Hub: By October of 1956, the Free-Lock Corporation had taken out ads for the hub in Popular Mechanics (and possibly Popular Science, in which they did publish later). In the case of this hub, there is only one screw along the outer radius.
This example hub from Willys Tech shows almost the exact hub that is advertised in the ad. The missing item is “patent pending”. In it’s place, the company stamped “Denver” (there may be “pat. pending” below the Denver). Hence, some referred to these as “Denver hubs”:
The company also produced a multiple page brochure. Unfortunately, I only have copies of photos that were posted to Craigslist (I welcome better scans if anyone has them): Continue reading