I am happy to have a ring in the shop with such a long, long history as well as a traceable provenance. This style of ring is called a gimmel ring, which indicates that it has interlocking "twin" (from "gemellus" in Latin) parts. It can also be called a fede ring when it features the clasped hands, an ancient symbol of good faith and trust. You can see a very early example of a fede motif ring right here in the collection of the Walters Art Museum.
This style of ring makes many appearances in history. It was often used as a wedding ring because of the powerful symbolism of the interlocking bands. We find reference to "joint ring" in Shakespeare's plays and there are early examples of gimmel rings in museum collections around the world, including a this piece from the early 1600s at the Victoria and Albert Museum and a wonderful German example from the late 1500s at the Metropolitain Museum of Art. Here are a few more examples from the Victoria & Albert Museum (image linked):
Early gimmel rings were interlocking but we don't see a nicely functioning pivoting mechanism (or pin) until the 1800s. And it wasn't until 1939 that an American designer Samuel Kalina applied for a patent on a design for such a feature. The gimmel/fede ring that I have in the shop right now is his design, manufactured from these very drawings:
This particular ring was made from a design patented in 1940 by a Mr. Samuel Kalina. It is an unusual opportunity to see the original drawings for the ring as well as admire the finished product.
As Mr. Kalina explains in the patent write up, "the principal object of the invention is to provide a novel ring embodying sections for containing identification data, engraved or otherwise inscribed thereon, and constructed and arranged for clasping together so as to conceal such data, together with a form of clasp having a significant sentimental value aspect when fastened."
This ring is done in sterling silver with two interlocking bands and clasped hands. The detail on the hands and cuffs is incredible and the laurel-leaf casting on the top and bottom of the bands is exquisite. There other marvelous examples of gimmel/fede rings on Etsy - many of them older than mine - including this 18K gold triplet fede ring (concealing a heart!) over at one of my favorite shops, The Deeps.
And thus concludes your history lesson for the day :)
Patent image and quotation courtesy of Google Patents, historical gimmel ring images courtesy of the collection of the Victoria & Albert Museum, 18K gold gimmel ring courtesy of The Deeps