Early mechanical
calculators - Carl Walther, c. 1924.
Walther Model RMKZ, S/N 51434
Digits: 10 rotor, 8 counter, 16 accumulator
Dimensions: Body 8"W x 5"D x 5"H, overall width, including handles, 11"W
Weight: 7.9 lbs.
Manufactured: Gerstetten, Germany, 1948
After the Arithmometer, the pinwheel calculator was the next major
mass-market mechanical innovation. It used retractable pins instead of the
stepped drum for decimal input. The first practical
implementation was that of Poleni in
1709, then Braunin
1720s, and Roth and Staffel around 1840, but was
first made successfully for mass production by Willgodt Theophil Odhner a
Swedish immigrant to Russia, see video below. Production began in St
Petersburg in 1890 and was very successful until the Russian revolution of
1917 when the factory was shut down. From 1892 to the
middle of the 20th century, independent companies were set up all over the
world to manufacture Odhner's clones and, by the 1960s, with millions sold,
It became one of the most successful type of mechanical calculator ever
designed.
The machine is built from aluminum-alloy castings and is relatively
light in weight. It has a setting check dial and tens-carry on the counter,
but no back-transfer mechanism. The carriage is spring-loaded towards the
left, and is moved one step at a time by the two vertical levers next to the
winding handle. A button at the front releases the carriage detent to allow
continuous movement. The accumulator register has small thumbwheels next to
each numeral wheel to allow values to be entered directly, eg, in setting up
a division.
Carl Walther GmbH is a German company better known for making
weapons such as the Walther PPK that James Bond is so fond of. Carl Walther
founded his company in 1886, making hunting rifles and selling them in his
gunshop in Zella-Mehlis. From 1908 the company started making pistols
instead of rifles. Carl died in 1915, and from then on the company was run
by one of his sons, Fritz Walther.
The treaty of Versailles at the end of World War I severely
restricted arms manufacturing and trade, so Walther had to diversify. In
1924 they started producing calculators. This came about in cooperation with
Mercedes, who had a factory in Suhl just a few kilometres away from Zella
Mehlis. Mercedes made pinwheel calculators under theMelittabrand,
but wanted to focus their production on theMercedes-Euklidtype
of machine. Walther then took over the production of the Melitta
calculators, and were allowed to sell them under the Walther brand name,
too. Soon they started developing them further, including electrically
driven models. In 1931 they also manufactured the Tasma, an adding-listing
machine with a full keyboard which had until then been made by Thales,
though it seems this was never sold under the Walther brand name.
The Walther factory was destroyed in the second world war, no
doubt due to its arms manufacturing activities. Zella-Mehlis was in the
Soviet-occupied region of Germany, and Fritz Walther decided it was better
to rebuild the company and factory in the Allied-occupied region. He and
some of his engineers settled in Heidenhelm, where they set up a basic
workshop. In about 1947 they were ready to set up a factory to manufacture
calculators in the nearby town of Gerstetten and then another in
Niederstotzingen. A few years later in 1953 the company had grown enough to
restart the arms manufacturing in a new factory Ulm, at which point the
calculator business was split off as a separate company, Walther
Büromaschinen GmbH.
From 1952 they also started making electrically driven, 10-key
adding-listing machines, such as the Walther SR-12. This machine was also
sold in the USA by Felt & Tarrant under the name Comptograph 202. Fritz
Walther died in December 1966, and was succeeded by his son Karl-Heinz
Walther. By the late 1960s the WSR-160 was the only remaining pinwheel model
still in production, but its end date is somewhat uncertain (some sources
say 1968, others 1971). The other desk calculators became more electronic,
and remained in production until the mid 1970s. The Walther Büromaschinen
company went public and then became Walther Electronic AG, and later
specialized in scanning and sorting machines under the name Walther Data
GmbH.
Video describes the mechanical principles
behind the pinwheel calculating machine. Courtesy of The Visual Guide to
Mechanical Computing.™