Numerous designs, notably European calculators, had handcranks, and locks to ensure that the cranks were returned to exact positions once a turn was complete. The latter, type, rotary, had at least one main shaft that made one continuous revolution, one addition or subtraction per turn. Later on, some of these mechanisms were operated by electric motors and reduction gearing that operated a crank and connecting rod to convert rotary motion to reciprocating.
The illustrated 1914 machine is this type the crank is vertical, on its right side. The former type of mechanism was operated typically by a limited-travel hand crank some internal detailed operations took place on the pull, and others on the release part of a complete cycle. And the Curta is proudly marked “Made in Liechtenstein,” possibly the only industrial export of that postage stamp-sized coiuntry (which, of course, issued a postage stamp to honor the device.Two different classes of mechanisms had become established by this time, reciprocating and rotary. Plus, there’s the amazing story of its inventor, Curt Herzstark, who designed the machine while a prisoner in the Buchenwald concentration camp. It looks a bit like an slightly oversized peppermill, if Swiss watchmakers made peppermills.
(Jake recently acquired a Curta, the Ferrari of crank-operated calculators. So I am happy that some in the younger generation are willing to do the work of restoring these beauties.
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Mechanical calculators were painfully slow by electronic standards and needed lots of maintenance (those levers in the photo of the Friden, top, represent the complex mechanical logic of the machine.) It was generally a blessing when they were replace by electronic calculators and, ultimately, by software such as Mathematica, Maple, Matlab, and Sage.īut those wonderful old machines created a intimacy between analyst and data that doesn’t exist anymore. The space at the Rackham graduate school included a plugboard-programmed IBM accounting machine (ancient even then), a counter-sorter, and a printer, and when everything was running at once, it sounded more like a stamping plant than a lab. The stat labs at the University of Michigan where I would were big rooms filled with dozens of machines, all going at once, making a glorious racket.
These calculators made a marvelous noise–motors whirring, gears meshing, bells ringing. Pinwheels, setting rings, and shaft of an Odhner 227 The last generation of Friden mechanical calculators had a square root function built in, an enormous benefit in stat work, which requires computing lots of square roots. Later models replaced the crank with an electric motor and moved the carriage automatically. Division was a bit more complicated, but was basically the same process in reverse and could be carried out to as many decimal places as you had digits in the register. The answer would appear in the accumulator register.
You would then turn the crank 5 times, move the carriage one place to the right, and turn the crank twice.
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On the early manual machines, to multiply, say 135 by 25, would enter a number to be multiplied from the keyboard or by rotating pinwheels. They were basically glorified adding machines which did multiplication as repeated addition and division as repeated subtraction. Mechanical calculators were conceptually simple and mechanically extremely complex. I was a student just before the advent of electronic desktop calculators (the ubiquitous personal calculators came along a few years later) and I spent a substantial part of my life doing statistical analysis on a mechanical calculator and a spreadsheet, which in those days was a ledger-sized sheet of ruled paper. These machines were obsolete long before he was born, but a visit this past weekend brought back a wave of nostalgia. My son, a mathematician at the University of Louisville, has a new hobby: restoring mechanical calculators. Steve Wildstrom on Ma“Naked” Friden D10 (Photo: Jake Wildstrom)