ANTIQUE LUDWIG SPITZ & CO. TIM "TIME IS MONEY" STEPPED DRUM CALCULATOR 1907-1940

The following information is cited from: https://www.jaapsch.net/mechcalc/unitas.htm#tim

The TIM ("Time Is Money") calculator is a stepped drum calculator based on the Thomas Arithmometer. It was made by Ludwig Spitz & Co. in Germany from 1907 until about 1940.

It has an input register at the front which uses sliders for each digit. It has a carriage containing an output register and a revolution counter. There is a crank to the right of the input sliders, and each turn of that crank will normally add the input to the registers, and increment one digit of the revolution counter. The carriage can be moved by hand directly, through using the large knob on the left hand side to tilt the carriage up, slide it, and drop it into a new position. This allows you to add the input to higher order digits of the output register, which is part of multiplication. To the left of the input sliders is a lever that switches between addition and subtraction. In subtraction mode a turn of the crank subtracts the input from the register and decreases a digit of the revolution counter.

Note that the output register in the carriage does not have a built-in carry mechanism. Instead, the carries are performed by the mechanism in the body of the machine. This means that when the carriage sticks out to the left of the machine, those leftmost digits of the register cannot be affected by a turn of the crank. This is usually not a problem. If a carry occurs from the leftmost place of the mechanism, a warning bell rings. The revolution counter has no carry mechanism at all. Each digit wheel can move forward from zero to show the black digits 1 to 9, or move backward by subtraction to show the red digits 1 to 9.

There are two sliders on the right hand end of the carriage which are used to clear the output register and revolution counter. You have to tilt the carriage to disengage it from the mechanism, and then push one or both of the sliders to the right. There is a clearing lever below each digit of the input register. If you push one of those levers down, the corresponding digit and all the digits to its left are cleared. If you push a clearing lever up, then the corresponding digit and all the digits to its right are cleared.

This great piece of rare early computational history can be yours, perfect for the avid collector of rare antique calculators or just who appreciates amazing early machines. In fact, an example of this Ludwig Spitz "Time is Money" model calculator is displayed at the National Museum of American History.  This item will be double-boxed and insured for safe travel.  As much as we appreciate prompt payment, please wait for for final invoice which will include the cost of the insurance.  Thank you for looking. Feel free to email me with any questions.