The three adding shafts are clearly visible across the top of the three horizontal segments of the adder, each consisting of escapement wheels and epicyclic gears. The solenoids below the escapement wheels activate the escapements when they receive a pulse from a ticket issuing machine via a multiplexer. Bets are recorded as angular displacement of the adding shafts and the total investment is recorded on the counter seen attached to the front of the vertical side plate, above and parallel to the adding shafts.
The distance between the teeth of each escapement wheel on the adding shafts determines the value of the bet, the fewer the teeth on a wheel the higher the value of the bet they register. Note the mercury switch with part of its curved glass tube poking out at the bottom right of the adder on the side plate with two electrical connections visible. This switch was part of a security device that ensured the adder would stop accepting bets if any of the adding shafts lost drive power.
This adder represents mechanical computing on an industrial scale as these systems were mass produced long before the advent of digital computers that replaced them. These adders are an essential component of these early on-line real-time multi-user totalizator systems.
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