Unusual American Cash Register

This very unusual cash register from the late 19th century is in a wood case made of cherry. The circular top section and the handle on the drawer is made of nickel plated brass. I can not find a makers mark on the register, however I am unable to unlock the circular section and the name may be on the inside of of that section. The top of the circular section is inscribed 'Amount of Purchase" and "Patent Pending" . The register is operated by pushing a lever under the handle and pulling the drawer forward . The top section rotates a half of a revolution and there is a roller under the top that probably had a tape with the amount purchased printed on it. W: 17.5, D: 17", H: 10'.