This a proportional divider. I have one that looks the same. It was made in the USA by Dietzgen. I purchased it in 1959 to use for transferring dimensions from engineering parts drawings to exploded view isometric drawings. In those days IBM computers were very large mechanical machines that required parts catalogs for identifying replacement parts. I worked at IBM for several years, drawing the exploded view drawings of the components for creating and printing the catalogs.
I now use the divider to proportionally measure and change the size of leather patterns. Was very useful then and is still very useful today.