Mystery object

It's been a while, but this little mystery has provoked me into a blip moment:

I found a box of dozens of these - details are the same on all (rusted steel, little cutaway on the edge, angle of the hook etc) - tucked away in a very dark and obscure corner of a very dark and obscure cupboard at the local hall.
They could be almost anything and I haven't a clue.
The original building was 1906 and there have been a number of extensions and alterations since, so they could be from any time in the last 110 (or so) years - and something that might be used in a local School of Arts (or equivalent) hall, probably early 20th century.
That's all I know.

Feel free to guess (I certainly have), but I'd also quite like to hear from someone who actually knows...

Anyone?