Didn't feel like going to buy a safety door handle at a large retailer, so I fired up TinkerCAD and MeshMixer and this is the result. I may make an updated version after I have printed it and seen how it works.

I did this for a 2.5" handle diameter and extension from the door.

I assume no responsibility for the quality of this, as I am just a hobbyist messing around. I am printing this on a Dremel 3D printer (with green just because I can).

I will post Pics when the print is complete and also when I attempt to install it

UPDATE: Printed it, cheaped out on the settings and ended up with layers separating. Aside from that, I also noted that there seems to be an excess of plastic use and a few ridges I don't like. A redesign is in works.

I made this by measuring the dimension of my current handles, playing in TinkerCAD to build the design, meshmixer to build the hollows and then the Dremel3D slicer to print it.

1.7 means it is the 7th version of my 1st try.