Jaap's Mechanical Calculators Page

The Alexe Mini Calculator / Chadwick Add-A-Mite

The Alexe Mini Calculator Chadwick Add-A-Mite



The Alexe Mini Calculator
   Video
Chadwick Add-A-Mite
   Video
Patents
Links

The Alexe Mini Calculator

The Alexe Mini Calculator is a 5-digit counter, which was made by Meiwa in Japan from about 1965. The Alexe was also sold under the Ricoh brand, or with the name Rambler.

The Alexe Mini Calculator, in box
The Alexe Mini Calculator, with box
The Alexe Mini Calculator
The Alexe Mini Calculator, tabs close up
The Alexe Mini Calculator, rear
The Alexe Mini Calculator, rear close up


This is the instruction leaflet that comes with the machine. I have a Greek and an English one.

The Alexe Mini Calculator, Greek instruction leaflet front
The Alexe Mini Calculator, Greek instruction leaflet back
The Alexe Mini Calculator, Greek instruction leaflet front
The Alexe Mini Calculator, Greek instruction leaflet back

The Alexe Mini Calculator, English instruction leaflet front
The Alexe Mini Calculator, English instruction leaflet back


There are five buttons along the top, one for each digit, and pressing one of these will add one the corresponding digit. There are two tabs on the right hand side. If the top one is pulled out, then the buttons will subtract instead of add. Calculation is very simple - set the top tab to addition or subtraction, whichever you want to do, and then press each button along the top as many times as the corresponding digit in the number you want to add or subtract.

The bottom tab is used for clearing the register. If you pull it out and push it back in, it decrements all the non-zero digits of the counter, so to fully clear the counter you pull and push that tab until all the digits have become zero.

The mechanism has some notable features. The counter's digits are displayed with the use of number wheels that alternately move clockwise and anticlockwise, i.e. the first wheel moves clockwise when you increase its digit, but if you increase the second digit its wheel moves anticlockwise. This allows for a carry mechanism that works directly from one number wheel to the next, without an intermediate wheel between them. This affects the clearing mechanism as well. When you pull the clearing tab, only the first, third and fifth digits are decremented, and it is when you push the tab back in that the second and fourth digits are decremented. Another clever detail is that pulling the clearing tab automatically pulls out the other tab so that the wheels are set for subtraction.

On the back of the Alexe the following text can be read:
    PAT.41-16935 29011 Japan 758.598
    PAT.USA.3312395
I have not been able to find the Japanese patent, but the US patent can be seen below.

My first Alexe was originally sold in Greece, so it has a Greek instruction leaflet. It comes in a box with a cardboard base and transparent plastic lid. There is a sticker on the lid that has Meiwa on it, which is the Japanese manufacurer. Its clearing mechanism is slightly broken unfortunately, as the tens digit fails tends to get stuck at 1 or 2 instead of fully reducing to zero. I have since baought another one which works properly, and has an English instruction leaflet.

Alexe mechanism
Alexe mechanism
Alexe mechanism
Alexe mechanism
Alexe mechanism
Alexe mechanism
Alexe mechanism



Video

Here is a video where I demonstrate the Alexe Mini Calculator.




The Chadwick Add-A-Mite

The Add-A-Mite by Chadwick is a knock-off of the Alexe. It has a larger body than the Alexe so that it can stand on a desk. It has no subtraction functionality. The clearing moves in the opposite direction to the Alexe, so moving the clearing lever back and forth increases the digits to 99999, after which the units button should be pressed to reset it to zero. It was made in Hong Kong, and imported and marketed by Chadwick-Miller Inc. of Boston.

This machine should not be confused with the Add-A-Mite by Monogram of California. Chadwick were also responsible for importing other plastic adding machines from the far East, such as the Chadwick Mini-Calculator.

Add-A-Mite
Add-A-Mite
Add-A-Mite
Add-A-Mite
Add-A-Mite
Add-A-Mite
Add-A-Mite
Add-A-Mite
Add-A-Mite



Video

Here is a video where I demonstrate the Add-A-Mite.




Patents

PatentFiling datePublish dateNameDescription
US 3,312,39523-09-196504-04-1967Masaharu NaraCalculator

Links

Rechnerlexikon has a page on the Alexe.
Pablo Cesar Cafaro's Flickr page has an album of the Meiwa Alexe.
mechanicalculator.com has a nice picture of the Meiwa Alexe.
retrocalculators.com shows the Ricoh Alexe.
John Wolff shows the Ricoh Alexe and the Rambler.
Rechnen Ohne Strom shows the Chadwick Add-A-Mite.


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