Marchant Calculator

The Marchant Calculating Machine Co. was founded in 1911 by Rodney and Alfred Marchant in Oakland, California.

The company built mechanical, and then electromechanical calculators which had a reputation for reliability. First models were similar to the Odhner arithmometer. In 1918, employee Carl Friden designed a new model in response to patent challenges. It was a great success, and Friden became the chief designer until he left in 1934 to found his own company. In 1958 the company was acquired by the Smith Corona typewriter company in a diversification move that proved unsound; the company, which was now known as SCM, tried to stay competitive by introducing the SCM Cogito 240SR electronic calculator (designed by Manhattan Project veteran Stan Frankel) in 1965. Within a few years a tidal wave of cheaper electronic calculators had devastated their business, and by the mid-1980s, SCM's typewriter business, too, had been ruined by the advent of inexpensive personal computers used as word processors.

The first Marchant calculators differed greatly from their later Silent Speed Proportional Gears machines, which were by far the fastest of their type, running at 1,300 cycles per minute. These machines are of considerable technical interest, and are far better known than the earliest ones. Their mechanical design was very unusual in that their result dials (sums, differences, and products) moved at speeds proportional to the digit in the corresponding column of the keyboard. A '1' in the keyboard caused its dial to move the slowest, while a '9', the fastest. Probably the only other such machine was the European Mercedes Euklid, which had a very different (and apparently much simpler) design.

Carrying to the next higher order was done (effectively) by a 10:1 gear ratio, rather like traditional watthour-meter dials. This was probably unique in a calculator. While running consecutive 'add' cycles to develop a product in multiplication, much of the mechanism was running at constant speeds. All other mechanical calculators had result dials that moved only at one speed, but for different amounts of time, naturally for longer times when larger digits were to be entered. They started quickly, ran at one speed, and stopped quickly. (They also had mechanisms to prevent overshoot (known as coasting) when they stopped.)

...
Wikipedia