The TEKNA microknife featured a double ground blade rigidly mounted in a brushed stainless steel body and protected by a retractable sheath. First produced in 1984, this handy pocket knife is still sought after by collectors and outdoor enthusiasts.
The release mechanism for the sheath utilized a pair of collapsing fingers attached to the end of a long slender beam. On the opposite end of this beam was the release button, which protruded from the top of the knife. By pressing on this button, the fingers would slide against a pair of small ramps, and the protruding lip on each finger (which acted as catches on the sheath) would slide free, releasing the sheath. Two small compression springs would drive the sheath to the open position. The concept was prototyped, tested, verified, and put into production. It was also protected by US and European patents.
Shown are some early sketches of the concept, along with images from the issued patent, and some sample parts. The button and ramp were molded from acetal, the sheath was molded from glass reinforced nylon.
Also shown are mechanical sketches of a rivet concept which would rigidly attach the stainless steel blade to the tubular steel. The rivet provided for radial expansion, as well as vertical compression and clamp. The hatched areas represent a bronze bearing which also acted as guide for the retraction mechanism. The rivets were screw machined from 300 series stainless steel.