Well this one was truly a learning experience!

“Kelly”, I found out, is a just a company name:
http://www.kellyklosure.com/kk/products/index.htm

Next, the “swivel eye”! A ‘swivel eye snap’ can be admired here http://www.iboats.com/products/7/47982_seachoice_swivel_eye_...
Now I knew that it must be something that is ‘schwenkbar’ , but what about the ‘eye’?

The picture reminded me of the little thingie we always use when we go climbing – Karabiner.
So I began looking for Karabiner pictures

Ahhhh- the little in the Karabiner is the “eye” - auf Deutsch die “Öse”
http://www.proclimber.co.uk/catalogue/index.php?main_page=pr...

Next, I googled for Karaninersorten and found this site:
http://abstractconcepts.de/assets/s2dmain.html?http://abstra...

Unfortunately, there is no such thing as a Schwenkkarabiner, but there is a
“Schwenköse”, shown here: http://www.hebetechnik.at/produkteneu/lastaufnahme/bgtbs.htm...

In conclusion, I would propose to call the object a “Kelly-"Schwenköse”.

Langescheidt WB Technik also confirms eye= Öse

Maybe someone can confirm or give you another term. But you can't say I haven't tried;)))