Overview
This is a TIM model III calculator. TIM stands for Time Is Money, and was designed to speed up calculations in order to save money. This machine features eight digit entry via sliders, nine digit counter register, and sixteen digit accumulation register. It’s made of iron and brass, weighing in at around 20 lbs. It was manufactured by Ludwig Spitz & Co in Berlin, Germany from 1910 to 1930. It was sold in New York via Oscar Muller & Co.
The machine also has a protective cover that sits overtop of the machine when not in use.
Controls
The TIM machine has quite a simple method of operation. The main crank on the right hand side is used to cycle the machine. It can only be rotated to the right for all operations. On the carriage, there are two clearing levers that are used to clear the upper and lower registers. Sliders are used for entering numbers for operations. The main register dials can be set using small knobs benath the viewing window. There is also a comma slider beneath the counter register. Below each slider in each column is a lever used for clearing the input. It can be pushed up or down. Down clears the individual column and all the left while up clears the column and all columns to the right.
On the left side of the machine is a lever for switching between addition/subtraction or multiplication/division. This lever is used instead of rotation the crank the opposite direction.
Mechanism
The TIM machines had a surprisingly simple mechanism. The patent entry above shows a machine with keyboard entry, which is a bit more complicated. The mechanism is based off of the stepped drum principle. The input sliders move a gear up or down beside a drum. The drum has an increasing number of groves placed vertically on the drum. When the input gear is at the bottom of the drum and the drum is rotated, the input gear only moves one position. When the input gear is at the top of the drum, it moves nine positions. The input gear is connected to the counter and the accumulater register and increases or decreases their amounts based on the position of the add/subtract lever.
Internals
Some internal images after I got the machine and before cleaning. Many years of dust and gunk, but the machine was still functional. The front cover of the machine can be easily removed without a screwdriver for easy access and cleaning.
The bell is seen here for when the machine underflows.
Below is the disassembled carriage.
