The fastener industry is something Earl Size rarely, if ever, thought about. For 20 years, the Michigan-based native has owned a successful skate shop that provides services and repairs for hockey players and ice skaters in Troy, which is about 20 miles north of Detroit.
However, aside from the typical blade sharpening, Size noticed one task the customers of his shop had begun requesting — repeatedly.
“We’re frequently asked to tighten the components that secure the blade to the holder of the skate,” he shares. “Manufacturers design this boot to be lightweight and deliver as much performance on the ice as possible, which makes sense, but its weakest part are actually the rivets that hold it together.”
Much like any fastener that endures vibration, the rivets on each skate vibrate each time it hits and glides on the ice. And, eventually, they come loose.
“Sometimes, a skater will even lose their blade while on the ice,” adds Size. “So, one day I was thinking that there has to be a better solution other than repeatedly tightening these things. I mean…what if I added another component to it so that there’s no way the screw could come loose?”
The result: ForeverLok, a fastener design that uses just three items:
- A central threaded fastener
- A threaded intermediate fastener
- A retaining fastener
“Although ice skates were the inspiration, the idea almost took on a life of its own and became a much bigger project with far greater potential,” he says.
Size still owns his skate shop but this project has become somewhat of a second job for him. And the more he researched the fastener industry and refined his idea, the more pulled Size felt to see it through. During his pursuit, he happened upon the ideal artist (for mock drawings), patent attorney, and engineer to support his efforts.
“The more I learned, the more help I received, and the more compelled I felt to continue,” he says. “For example, I was referred to Tyrone Secord with Simek, LLC, a design and prototype company, who was an automotive engineer with more than 40 years of experience, and he told me he’d never seen anything like my design. I had so much positive feedback along the way that I somehow found a way to fund the testing and patents.”
Size’s idea is relatively simple. A retaining fastener holds a nut in place to physically prevent it from loosening. Although there are similar products available, this design is more compact than a conventional nut and bolt configuration. What’s more: it’s ideal for several major industries, including aerospace, power generation, military, heavy equipment, agriculture, infrastructure, and many others.
“Take the auto industry, for example,” says Size. “When vehicles are subject to vibration, dynamic loading, or thermal stress, critical fasteners can loosen. In fact, the most frequent cause of self-loosening is the side sliding of a nut or bolt head relative to the joint, which results in a similar motion in the threads.”
Typically, the gradual rotation causes a bolted joint to lose its preload, leading to fatigue failure. (Read more here.)
“However, the locking design of the ForeverLok requires no special pins, bolts, or tools to install or remove the nut. Plus, the design allows the fastener to be smaller, lighter, and more compact with a similar torque value to conventional fastener. These are major benefits in most industries that are trying to save on component weight and costs,” he says. And Size has the testing to prove it.
“After hours and hours of research on fasteners and time invested in my design, I thought I should probably find out how to test it and learn the standards for functionality.”
Size decided on three important tests:
1. Maximum torque test. “Essentially, this means the fastener is put together and tightened until it fails. In this case, we used a half-inch, bolt-and-nut configuration, which is standard, and a maximum torque of 90-foot pounds was recommended,” he says.
The design tested at 159.9 ft/lbs, a 77% increase over the 90 ft/lbs. “This meant, it was possible to use a smaller, lighter fastener to accomplish the same torque requirement.”
2. NASM 1312-7, which is a military test. “This is a slotted configuration test that bounces the fastener up and down a bunch of times. If it doesn’t break after 30,000 cycles or 17 minutes of testing, then you’re approved,” explains Size.
In the test, the nut-and-bolt combination is installed in a fixture, and that fixture is subjected to controlled vibration and cycles until the assembly loosens. “We hit 420,000 cycles with zero loss of torque retention and, since our bolt was still standing, we turned off the machine.”
The ForeverLok exceeded the military standard by 14 times. And although the military vibrational test requirements do not call for final torque measurements, Size’s design retained an unprecedented 93.5% of its original torque.
3. DIN 25201-4, which is the toughest transverse vibration standards. This standard tests the fastener 12 times. “The first time they ran 2,000 cycles and perform a transverse vibration test. If it receives 80% or better, then it passes. Our fastener retained 89% of its torque, surpassing the minimum retention pass specification, which sealed the deal.”
For Size, these successful results are just another reason to keep going. He officially began Multipiece Fastener, a new company that he set up earlier this year.
“The ForeverLok technology is currently available for licensing,” he says. “I want to remain flexible enough so that any manufacturer can invest in it if interested and that any industry can benefit from it since the design is ideal for so many different applications.”
The ForeverLok is versatile and reusable. It can be made of several materials (such as titanium, steel, and other metals and alloys, as well as plastic) and provide various configurations depending on a customer’s application.
“I feel so fortunate that I’m able to offer the fastener industry a solution that, in some cases, such as with automobiles or aerospace, could be life-saving,” says Size. “It’s been a long and expensive venture, but one I’m proud of.”