when you said vertical, suddenly made me think of this design
There's only one spring shown here because I'd rather not do perspective in Paint.
There would be either 3 to 4 of the springs on the real thing. It'd be wrapped really tightly with some kind thread, sinew, polyprop twine, then super glued. Then wrapped in a 1/2" heat shrink tubing. That should look quite elegant, I'm not sure about sturdiness. But wrapping it with a lot of thread (maybe even metal wire) and a 2 to 3 inch length of tubing should prevent it from slipping. Thereafter, all you'd have to do is adjust the hook part with pliers once in a while.
OFF COURSE THIS IS AN UNTESTED DESIGN AND JUST GUESSTIMATE.
Also, should file away a little bit of wood to seat the spring better as well as make some grooves for the thread to catch on to.
At a buck for 50 wooden clothespins, this should be relatively simple and useful design. Now I just gotta find some heat shrink tubing in the right size.
3 clothespin = 6 cents
Wrapping = almost nil, maybe 1 cent
super glue = ~ 10 cent (guesstimate)
heatshrink = ~ 25 cents (guesstimate)
TOTAL = 42 cents for Judo point
If anyone has these materials, try it and let me know how it turns out, since I'll be busy this weekend. maybe even monday too, depends on how powerful Sandy gets.