Jaap's Mechanical Calculators Page

Star Adding Machine

Star Adding Machine


Star Adding Machine
Video
History
Newspaper and Magazine Advertisements
Patents
Links


Star Adding Machine

This Star Adding Machine was made by by the Todd Protectograph Company. It has serial number 71,052, and was made in about 1923.

It has a 7 digit register. Below the register is a co-axial paddlewheels which are used for entering numbers. To enter a digit, put your finger on the paddle-wheel for that location on the paddle that is marked with the digit you want to enter, and pull your finger downwards until it hits the ledge at the front of the machine. As the paddle-wheel turns, the number wheel of the register above it is turned too, adding the selected digit. In the front ledge is a button that puts a brake on the turning number wheel so that the number wheel will not overshoot however fast you pull down on the paddle wheel. The paddle wheel springs back to its starting position when you release it. The register carries automatically using a spring-loaded mechanism.

The paddle wheels are also marked with complementary digits in a smaller font, and these allow you to do subtraction. To subtract a number, simply enter it using these complementary digits, including any leading zeroes. The row of red buttons at the top of the machine suppress any carry to the associated register number wheel, and are used to obviate the need to enter most leading zeroes during subtraction. Note that the right-most carry suppression button is useless since nothing carries into the units digit.

Star Adding Machine
Star Adding Machine
Star Adding Machine
Star Adding Machine
Star Adding Machine
Star Adding Machine
Star Adding Machine
Star Adding Machine
Star Adding Machine


The bottom plate of the case can easily be removed. The rest of the casing is more tricky to remove because the paddles of the input wheels are wider than the slots in the casing, and so all the input wheels have to be pushed all the way down and held there simultaneously.

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Video

Below is a video I made that demonstrates the Star Adding Machine.




History

This machine was originally designed and patented by Fred Doerr of Grand Rapids, Michigan. It was then manufactured by the Accounting Machine Corporation of New York between 1918 and 1922. The manufacturing and sales rights were then bought by the Todd Protectograph Company (Rochester, New York), and produced in various versions until 1928 using the names Star Adding Machine and Todd Visible Adding Machine.
The table below lists the versions and their distinguishing characteristics.

YearsNameDescription
1918-1922AMCO Adding Machine Made by the Accounting Machine Corporation (AMCO).
Two sizes - 7 or 9 digits.
1922-1923Star Adding Machine Made by Todd Protectograph Company. Identical to the AMCO, apart from the label.
Two sizes - 7 or 9 digits.
1923-1924Star Adding Machine In about April 1923 a carrying handle was added. This handle could also be folded down onto the input wheels and locked in place so as to keep the register's state safe from changes. The handle bears the text "MACHINE IN USE - DO NOT OPERATE". The right-most carry suppression button unlocks the handle.
1924-1926Star Adding Machine The machine now simply has a lockable cover with a key, and a separate carrying handle.
9 digit register only.
1926-1928Todd Visible Adding Machine This version has an input register displaying the entered number.
9 digit register only.

Newspaper and Magazine Advertisements

Here are some articles and advertisements I found in online archives. First those relating to AMCO.

1917-11 Typewriter Topics
1918-03-12 Indianapolis News - Indianapolis - Marion County
1918-04-15 Daily Tribune - Terre Haute - Vigo County
1918-04-16 Indianapolis News - Indianapolis - Marion County
1918-08-10 Indianapolis News - Indianapolis - Marion County
1919 San Francisco Chronicle Classified Directory
1919-02-10 Duluth Herald
1919-04-30 The Corpus Christi caller
1919-09-08 The Oklahoma City times
1920-05-25 Evening star

The following articles and ads relate to the Todd Protectograph Company, and the Star Adding Machine.

1914-07-29 The Washington herald
1915-11-22 Omaha daily bee
1919-10 Nations Business
1923-11 Typewriter Topics
1924 The American Digest Of Business Machines
1925 Ernst Martin
1926-08-22 Evening star


Patents

PatentFiling datePublished dateNameDescription
US 1,398,06816-03-191722-11-1921Fred H. DoerrComputing Machine
US 1,517,41228-08-192002-12-1924Fred H. Doerr, Todd Protectograph Company, Inc.Zero-setting Mechanism
US 1,560,38112-11-192303-11-1925Alton L. Gray, Todd Company, Inc.Locking Mechanism
US 1,787,25915-01-192730-12-1930Walter B. Payne, Raymond E. Bohrer, William Fuhlborn, Todd Company Inc.Input register

Links

Rechnerlexikon has pages for the AMCO, the Star, and Todd Visible adding machines.
Rechenmaschinen Illustrated has an entry of the Star Adding Machine with pictures.
John Wolff has an AMCO Adding Machine.
Arithmeum has an early AMCO Adding Machine
The National Museum of American History has two Star Adding Machines with covers here and here.
Christian Hammann has a Star Adding Machine with locking handle.
Bob's Calculators and Slide Rules has a Star Adding Machine with cover.
Industrial Alchemy has a Star Adding Machine with locking handle.
IFixIt has a (partial) teardown of a Star Adding Machine.
Museum of Applied Arts and Sciences has a Star Adding Machine with cover.
XNumber has a Todd Visible.


© Copyright 2020 Jaap Scherphuis, .