Kershaw Speed Safe - Assisted Opening Systems
Kershaw Speed Safe Info
Kershaw's Speed Safe technology was designed and patented by Ken Onion, who works for Kershaw Cutlery. They licensed the technology for their exclusive use in 1998 and released the first Ken Onion designed folders to utilize the technology, which completely revolutionalized the sporting knife industry. Speed Safe was the first assisted opening technology on the market, and created a huge stir when it was introduced. Every other cutlery company out there now had their own type of assisted opening technology in development.
Not only did it revolutionize the industry, but Ken Onion's Torsion Bar Speed Safe technology put Kershaw at the top of the game as far as high-tech sporting cutlery. Ken Onion's designs became the hottest production folding knives on the market. First with the Whirlwind and Random Task folders, and then the next generation of assisted openers which featured the flipper like the Chive, Scallion and Boa.
How it Works
The Speed Safe system is simple, and easy to implement. I've included some photos below of the mechanism, as well as some sketches from the Speed Safe Patent illustrating a couple different types of torsion bar implementations.
Basically, the torsion bar acts like a spring, and is bent and compressed when the knife is closed. When the knife is opened around 15-20%, the torsion bar engages and springs the knife open. If you look closely at the photo of the Avalanche you can see how the torsion bar is moved into a resting position when the knife is closed due to the location on the semi-circular cut-out.