Ancient US patent invalid over prior public use?

The Chicago Tribune re-reported a story from the Freeport Standard about LeBaron & Miller Interiors taking over a store once occupied by E & W Clothing House, which had a a "cash railway" or "cash carrier system." In this system, customers paid the clerk for their merchandise at the counter, after which the clerk grasped a small metal box or tube from a wire over his head, deposited the ticket and cash inside, pulled a cord that sent it sailing up a wire to a cashier on a balcony. The device bears the name the "Baldwin Flyer."

The story notes inventor James Baldwin took out a patent on a flyer for a wire system able to travel vertically in 1931. An illustration is labeled US patent No. 1,784,776 of 1930. Notwithstanding, the Indianapolis installation predates that patent.