In 1945, a government inspector/inventor named Stukenborg was inspecting the turnbuckle parts that R. E. Bell Manufacturing was preparing to ship to the government. He was curious about the elaborate methods that were used to safety wire the turnbuckle assemblies so that they would not lose tension during flight. Airplane mechanics had to learn the “Double Spiral Safety Wrap” method to securely safety wire the critical airplane flight controls. The safety wiring took a considerable amount of time and the assembly was often in the most difficult-to-reach locations on the airplane.
The inventor’s mind of Mr. Stukenborg imagined that if a slot were milled through the threads on both the male and female parts, and if the slots were then lined up, a pin could be inserted into the channel that would prevent the parts from rotating. The Stuke Lock clip-locking turnbuckle was his time-saving solution.
It took roughly the life of the patent for the invention to become widely accepted by the aviation industry. Eventually the concept was incorporated into the Military Standards. Bell-Memphis was put on the government QPL (Qualified Producers List) of companies that were authorized to manufacture this critical flight component. The patented locking clip was not a big money maker but it helps explain why a small manufacturer in Memphis, Tennessee stayed in the aerospace manufacturing business for so many years.