Steamer (strange - just wait)
What you have there is an adjustable angel box for a thing called a
reach rod.
On ships, valves are often placed where they need to be (wow) but this
precludes a normal (even for shipboard) human from being capable of
operating said valve.
So - they fit a reach rod.
A simple one is a long rod with a handwheel on one end and something
that works the valve handwheel on the other and maybe some support along
the way.
Sometimes these thing go up 6 decks.
Sometimes they have to take a sideways to go around a piece of something
major. (That's where your piece comes in.)
They come in right angle , 45 and the really expensive (yours)
adjustable.
Matt Colie
Lifelong Waterman, Licensed Mariner and Perpetual Sailor

steamer wrote:
--Found this at a junkyard; although my application isn't likely
to be anywhere near water (except rain!), rumor has it this may be nautical
in origin, but nobody seems to know the proper name for it or whether or not
they might still be available somewhere. First three photos on this page:
http://www.nmpproducts.com/artcar0508.htm
--Any help appreciated,