Willison coupler help needed

I've searched the web trying to find so information on a Willison coupler I came across. I think it's a salesman sample.
Its about 6 inches in width and is attached to a stand, 3.5 inches overall height.
Might be made from stainless steel. It says Willison on the top and patented on the bottom.
Any information would be appreciated.

Randall

The Willison SA-3 coupler is the design used by Russia and the other countries that use 1520mm gauge track(Belarus, Ukraine, the Baltic republics, plus Finland).