This technology history page contains an image, which is one of several belonging to the photo gallery pages, which are part of several pages relating to the invention of the world's first automatic totalizator in 1913 and Automatic Totalisators Limited, the company founded in 1917 to develop, manufacture and export these systems.

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Brough Park Adder- Electro-Mechanical computing on a large scale

This is one of the Forecast Pool adders in the Automatic Totalisators factory at Chalmers Street in the Sydney CBD, to be installed at Brough Park Newcastle upon Tyne in 1936. As with the previous images in the Photo Gallery of the Brough Park machinery, the storage screws, a mechanical form of memory can be seen. There are 10 of them and they connect the adding shafts with their escapement wheels and epicyclic gears at the rear of the adder to the large cogs behind the counters. They sit below the bars that hold the adder mounting plates together. They have the circular cam wheels on them that look like a tea biscuit. Each cam wheel operates a contactor, that transfers the rotation of the associated shaft, which represents investment, to the display equipment. The purpose of the storage screws, is to buffer the rotation of the high acceleration adding shafts with the machinery that is slower to respond due to higher inertia restricted acceleration.

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For more detail on the storage screw have a look at the first image in the Brough Park section of the Photo Gallery, which can be viewed by clicking on this image and scrolling up and selecting the first thumbnail in the Photo Gallery index in the Brough Park Newcastle Upon Tyne 1936 section. Additionally, there is an Engineering Drawing of the storage screw in the first image of the Figures from George Julius' paper presented to the Institution of Engineers Australia in 1920 section of the Photo Gallery which follows the Brough Park section.

The ten adding shafts are clearly visible across the whole rear of the adder occupying about a third of the footprint of this adder. They sit beneath the ten visible fixed support bars oriented front to rear which in conjunction with out of view support bars connect the two end plates of each of the ten adding shafts. The distant end plates of the adding shafts constitute the back of the adder. The shaft adder end plate supporting bars are the lower group of ten visible support bars. The higher group of ten visible supporting bars which are horizontally aligned with the lower bars run above the storage screws and assist in securing the front of the adder to the rearward section. There is an Engineering Drawing of the epicyclic gears and escapement wheels on an adding shaft in the second image of the Figures from George Julius' paper presented to the Institution of Engineers Australia in 1920 section of the Photo Gallery.

The escapement wheels on the adding shafts can be seen in the image above. Below these wheels are solenoids that operate the escapement mechanisms that allow graduated rotation of the escapement wheels. The solenoids are activated by impulses from the Ticket Issuing Machines. There is an Engineering Drawing of an escapement wheel, escapement mechanism and solenoid in the third image of the Figures from George Julius' paper presented to the Institution of Engineers Australia in 1920 section of the Photo Gallery.

The angular motion of these escapement wheels represents the transaction values. The fewer the teeth on the escapement wheel the greater the movement with one operation and the higher the value. The epicyclic gear arrangement that connects the escapement wheels along the adding shaft cumulatively adds the rotation of the escapement wheels along the shaft such that when it arrives at the storage screw the rotation is the sum of the rotation of each escapement wheel on the adding shaft. There are six escapements and solenoids on these adding shafts.

One of these shaft adder units is visible on the table to the left of this adder. Nine complete adding shafts attached to the storage screws and drive cogs can be seen behind the adder on display, on a table at the rear of the image, in the process of being assembled. The cogs attached to the adder table in the foreground, provide the drive for the adding shafts and storage screws and are driven by a motor that will be installed underneath the adder table.