Kohner Easy Adder

Kohner Easy Adder
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Kohner Easy Adder

The Easy Adder is a toy adding machine by Kohner Bros Inc. It has a single dial on the front like an old rotary phone. Above it is a window with a two-digit register. By dialling a digit, that digit is added to the register. The switch to the right of the dial can be moved to subtraction mode, and this changes the order of the digit labels around the dial and the direction of the arrow indicators. In subtraction mode you can only turn the dial counter-clockwise, which subtracts the selected digit.

On the back it has a cardboard plate with the instructions. This can be popped off to access the mechanism.

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History

Kohner's history starts in Tachau, in the Austro-Hungarian Empire (now Tachov in Czechia). In 1874 Moritz Kohner started a company there that made small wooden products, like beads and toys. His sons Emil and Max joined and eventually ran the company, and later still Emil's sons Paul and Frank inherited it. By the mid 1940s they had established an office in New York to import their beads and toys, and from there grew what became Kohner Bros Inc.

One of their most popular toys was the Push Button Puppet - a figurine that stands on a base and moves when you push up on the button inside the base. For this they licensed the 1947 patent by the Swiss inventor Meinrad Marty (US 2,421,279) though such toys were first made in Switzerland in 1932 by Walter Kourt Walss and were known as Wakouwas. Kohner also began to use plastic parts in their toys, for example push button puppets with a plastic base but a wooden figurine. By the 1960s their toys were wholly plastic and made in the USA.

The Easy Adder was invented by William Nutting and Albert Stubbmann. They worked for Kohner Brothers and they each have several other patents for toys, though neither has any other calculator-related patents.