Any guess what this stage-size tambourine / drum-head trick is?

I recently bought this at auction for an impossibly low price, despite not really knowing anything about it.  Any ideas?  It's obviously a super-sized tambourine-style production device, but beyond that I know nothing else.  (Who made it?  When?  What are those pieces of metal on the side meant to hold?  Etc.)  I'd appreciate any info you can give me.