This is a design inspired by Pentland_Designs' "Shoelace Locks". While I like the concept I found their original design to be overly complex and very dependent on tight printer tolerances. This is my take on it.
Use ShoeKlips to easily and quickly secure shoelaces without needing to tie or untie knots. The ShoeKlips clip together easily with one hand and also release easily with one hand. When released the clip will not undo itself all the way but rather stop on a second internal catch. This second catch is sloped so if you do need to completely undo the ShoeKlips you can by wiggling the two sections apart.
20/04/2017 Update: I've added a second type of Klip Arms with the tips more severely rounded. I found that on some print settings with PLA those points were still coming out too pointy which meant they could poke you in the finger when closing the klips. You can quickly round the tips off but why have extra processing. With this newer version they are even more rounded and should always be comfortable to use.