Ninja Lock - Indoor Child Door Lock

If you have kids, chances are they are ninja's just like mine. These little ninja's will get into anything and everything (including taking a sharpie to your white kitchen cabinets). I designed this device that slips over the door (preferably near the top) and locks the door within the door frame so that we can stop our little ninjas in their tracks. It also has a built in mechanism to prevent smashed fingers.

I've tested this with my 3 and 2 year old. It works great!

Let me know what you guys/gals think in the comments and/or if you would like to see modifications.

I plan to improve and come out with more child ninja safety in the future.

*Update: Added the .f3d file from Autodesk Fusion 360.

Update (10/23/15) - After a good solid month of use, I had one of these snap right in bend of the arm near the pet that latches onto the door. I'm working on a fix for for this to make it stronger.
Also, I have some changes that should help with the triangle part scratching the door frame. My print bed is jacked up so as soon as I get some new glass, I can test it.

Feel free to comment or PM me if you have any ideas on improvement.

https://youtu.be/iA1tRmMiJ1M