Before there were slide locks, liner locks and frame locks, there were friction folders.
This type of knife has no lock at all. Instead, it has an extended tang that, when open, sinks between the handles to hold the knife in place. You can then lay a thumb on top of the blade tang for even more non-locking leverage.
Source of friction
Thanks to such a low-tech design, friction folders were among the first folding pocket knives known to man.
Advancements in knife design have largely replaced them but they present a perk beyond their simple, old-timey design: lacking any locking mechanisms, friction folders are technically legal to carry anywhere locking blades aren’t (like the United Kingdom and some places in the US).
Today, only a handful of EDC brands offer contemporary takes on the classic pattern. One such example from WESN.
