My old mum in law shuffles around the house using her sholly...(shopping trolley), I removed the cloth lid years ago and replaced it with a flat area that she uses to carry a tray from kitchen to her chair. I watched her start to struggle with having the tray on her lap and decided that I could make her life easier with a little bit of woodwork.
Step 1: The Build Begins
The build is pretty simple a few cuts of good quality ply, a piece of piano hinge and a couple of large zip ties to hold it in place.
I measured up the height of the chair arms and found that they were around 3" below the top of the sholly so I offset the hinge to suit the difference., I also put an upright at the back so that she wouldn't chase her plate off the back edge. :)
Step 2: All Done!
I gave the woodwork a couple of coats of varnish then fitted it on using the zip ties around the frame of the sholly.
I gave it to mum to test drive, it works a treat, it is nice and stable and she finds the height just right, sitting just above the arms of her chair.