Since I discovered how awesomely useful one of these is from living in flats that had one installed a couple of times, I've wanted to produce one myself. See: https://en.wikipedia.org/wiki/Sheila_Maid https://www.google.com/search?imgtype=&hl=en&q=sheila+maid&tbm=isch

The basic concept is a rack of narrow planks or similar suspended between a pair of coathanger-like blocks, which are usually made from cast iron. The frame is lifted up to ceiling-height with laundry on it using a pair of pulleys, one of them a double-pulley, and some string. I am trying to design one that could have the end-pieces 3D printed, and if required for heavy laundry (big towels and sheets), possibly used in lost-wax casting with something like scrap aluminium or brass, with the rest of the materials (beams, pulleys) from salvaged or cheap stock.

Plastic endpieces are probably only capable of supporting small laundry items repeatedly, and I have created a separate small test-piece model in order to find out how much weight can be supported by the most-stressed part of the hangars, the string/rope-hole at the top, before it plastically deforms or breaks. I have yet to perform these destructive tests. I guess that a plastic part would have to be ridiculously thick in order to form the frame of the pulleys and not break, so I am currently thinking that those ought to be simply made out of parallel pieces of sheet-metal, unless you can find some suitable pulleys to re-use, which would be even better.

A blank hangar model is supplied so that you can edit it to suit whatever kind of beams you want to support.

Someone near me threw out an IKEA bed called 'Sultan', and I salvaged the set of pine planks that make the lateral slats for the bed, which measure approximately 60mm by 11mm in section by a couple feet long and are rounded along the edges. I intended to strip them in half along their length to make some 30x11mm beams for this contraption, and created a custom hangar for the purpose, but then I was forced to leave those planks behind when I moved out of my last flat, so that file is now redundant for me unless by fluke I come across identically-sized beams for this again.