I have a single blade Stanley box scraper, with the arched logo on the
blade, that is similar.  The scraper head is mounted on a 'Y' shaped handle
that permits the head to operate like a gimbal.

Somewhere in the deep, dark and dusty corners of my memory, your mystery
thingy brings to mind a line drawing in a book, possibly one by Alex
Bealer, of a floor plane that was mounted on a long handle.

Tim

Contemplating a sticking board for an upcoming project.