Corona Standard 20
Yet another find from Japan. This is a very pretty, well-though out machine, with one of the smallest pinwheel cylinders I've ever seen on a regular pinwheel machine. The serial number is prefixed with "S20", which presumably stands for "Standard model 20". Obviously the outstanding feature of this calculator is that it has its revolution counter and result register sitting on top of each other in the very wide carriage. This means that the transfer of the drive to the revolution counters is through a gear train and a shaft that sits at the front of the carriage.The paint quality on these machines is astounding - it is a beautiful deep green, that has survived remarkably well since approximately 1952, when these things were built by the Corona Calculating Machine Company in Tokyo, Japan. This may have been (yet another) ruse to disguise Bluestar calculators as a different brand - the main and clearing cranks bear a large resemblance to Odhner and Bluestar machines, as do the comma sliders. There is a direction indicator on the top cover. The gear train on the left is neatly covered with a painted cover, also on the inside, and the little lever at the bottom left is a really smart idea - it is pushed to the left when a division is set up and the dividend is cranked in. It prevents the counter register counting for one turn, then springs back to its normal position, re-engaging the counter. I've never seen that before!
I'll let you enjoy the pictures:
Tiny pinwheels:
Carriage in standard position
And to the right:
Wait, what ? There's two of them !?
