Circa 1938, originally featured in Mechanix Illustrated. From Modern Mechanix via Gimcrack, which is frequently NSFW. Those are some serious old lady shoes!
Could be either a spanking machine or a kicking machine depending on which way the wheel is going. Either way it is kinky.
ooops.... I didn't realise this was from modern mechanix, I found it somewhere else a long time ago. I think the Rain Dears image came from the same place but it was so long ago that I've lost the link.
my apologies to modern mechanix, I'll check there before posting similar things again
You can see this very shoe tester in action at the Exploratorium museum in San Francisco. It's a little bit hidden: if you go to the second floor, and then look over towards the back of the museum, on top of the labs, it's right there -- and they even have its speed control exposed, so you can make it go faster or slower :-D
my apologies to modern mechanix, I'll check there before posting similar things again