Author, Publisher, Developer, Stitchcoder


Visible Lock

My purpose in getting a laser cutter was to make visible mechanisms, in order to make their operation clear. Here's the second example I've been working on: A visible pin-tumbler lock. With the key out, pins block the "core" from moving. But when the key is put in, the pins are all lifted to just the right height so that their tops line up along a "shear line". In a typical padlock, the core is then free to rotate, but in this version (as in some bike locks, for example), the core can instead slide out far enough to free a latch previously held in piece. Watch the video and it will all make sense (which is of course the whole point of making these things).

What the video doesn't show is that you can also pick this lock in the traditional way, by tensioning it (pulling gently on the core) and then using a thin tool to lift the pins one at a time until you find the one that is binding, then repeating until they all clear.

By the way, notice that the "springs" are completely bogus. In a real lock, springs push the pins down, but in this one the springs just act like small weights. The lock has to be held vertically so gravity can act in place of springs. Why did I do it that way? Because I haven't yet been able to figure out how to make acrylic springs that are weak enough to work for this situation. Everything I've tried has pushed way too hard, making it impossible to insert the key without a lot of wrangling. Acrylic is a terrible material to make springs out of, though I did get some extension springs to work pretty well in my previous mechanism.

Theodore GrayComment