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The Storage Screw was designed to solve a problem associated with inertia. The adding shafts with their escapement wheels and epicyclic gears could respond quickly to the demands of betting as they were relatively low in mass. When it came to large counter wheel indicator displays or any larger mass devices these had to overcome significant inertia. In simplistic terms, as transactions are recorded as increments of rotation, a screw is wound into a nut by the fast response part of the machinery capable of keeping up with the requirements of the bet traffic. At the other end the nut is unwound from the screw, working to return the screw to its starting position, at a rate that the slower to respond equipment can accelerate or decelerate at. The screw remembers the rotation generated by the fast adding equipment and is read by the acceleration limited heavier equipment which eventually exceeds the angular velocity of the screw and starts catching up. To have a look at an Engineering Drawing of this storage screw, go to the Figures from George Julius' paper presented to the Institution of Engineers Australia in 1920 section of the Photo Gallery by clicking on the image and clicking on the first icon in this section.
Following are some comments in the words of George Julius, extracted from a paper he presented to the Institution of Engineers Australia on Thursday May 13th 1920 titled Mechanical Aids To Calculation, when a machine that had been built and tested capable of supporting 1,000 terminals and a sell rate of 250,000 bets per minute was demonstrated.
In other words, the mechanism that stores up the records has to control a variable speed gear, which will as required gradually speed up or gradually retard the counters, and so avoid all shock to the mechanism.
The epicyclic gears are made as light as possible, and are urged forward by " coil springs " and not by "weights." This ensured the instantaneous response of the epicyclic gears to the demands of the ticket-sellers. The movement of these gears so obtained is transferred to a " storage " screw which serves two functions, firstly, that when the machine is at rest it locks the driving gear which operates the counter wheels, and, secondly that when issues are to be recorded, it stores-up the records until they are registered by the counters. Immediately the tickets are issued the epicyclic gears instantly operate, being driven by the coil spring, and in so doing they turn the screw which then unlocks the driving gear for the counter, and the counter begins to operate. In so operating, this driving gear also moves a nut, which, acting on the storage screw, tends to bring it back to its normal position of rest, and thus again lock the counter driving mechanism. Thus the epicyclic gears in picking up impulses received from the ticket-sellers move the screw backwards, and the, driving gear of the counter is always trying to overtake this movement and thus return the screw to its normal position.
The movement of this screw is so arranged that it also controls a variable speed friction gear through which the counters are driven. During any period of acceleration in the issue of tickets, the screw is withdrawn in the nut faster than the counter operates, and this through the friction gear speeds up the counter, and the nut, in an endeavour to overtake the movement of the screw, and a condition of balance is ultimately established. If the issue of tickets is retarded or ceases, the nut immediately gains on the screw and brings it forward, thereby picking up all the stored-up records, and by means of the friction gear gradually slowing down the counter until when all the records are recorded, it quietly comes to rest. The rotation of the nut also is utilised to continually rewind the coil spring which operates the epicyclic gears, and thus ensure a steady driving effort on these gears.
The whole operation is entirely automatic and the speed is adjusted to suit the requirements of the ticket issuing. The arrangement of gears, screw , and nut is shown diagrammatically in Figure No. 10, and in more detail in Figure No. 11.
The part of George's paper that is pertinent to this website is presented in the Mechanical Aids to Calculation Chapter of this website.
The storage screw assemblies can be seen as cylindrical shafts that connect the adding shafts at the rear of the adder, with their associated escapement wheels and epicyclic gears, to the large cogs behind the nearest stationary mounting sections of the frame. These mounting sections look like church steeples with large circular windows in them and are located behind the pairs of meshing cogs, which have their lower cogs attached to the front of the table. In other words they are the longest round shafts running from the rear of the adder to the cogs at the front which are the highest cogs in the adder. These cogs attached to the front of the table provide the drive for the adder mechanism and will be driven by a motor under the table when it was installed in Brough Park. When I first read the note on the back of the photograph I wondered how you could tell that the middle shaft of each section was sped up. When I realised that the cogs on the front of the table were the drive cogs it became obvious. The gear ratio of each middle shaft of a group of three has a larger driving cog and a smaller driven cog than the others which means these driven cog shafts will rotate faster than the others.
As I have mentioned the adding shafts above, if you wish to have a look at an Engineering Drawing of the epicyclic gear arrangement and escapement wheels on this shaft, go to the Figures from George Julius' paper presented to the Institution of Engineers Australia in 1920 section of the Photo Gallery by clicking on the image and clicking on the second icon in this section.
The following is my simplistic conceptualisation of the storage screws, as I have never worked on any of the Julius Totes or seen one working. I worked on the computer totalizators after Julius tote production had ceased. I find the analogy of the nut and screw a little hard to comprehend however I think this is because of some preconceived ideas. One thinks of a nut as relatively short and a screw as relatively long. Additionally one tends to think of one end being stationary with the screw being held in position whilst a nut is tightened on it or the screw rotating into a fixed or held nut. The nuts in this system are long and the screws short and both rotate. The nuts in this equipment, are the long tubular sections, as previously identified in this image, which are threaded on the inside. Each of these tubular nuts rotate in the opposite direction to the adding shafts driving the screws, if the screw is not in its resting position, effectively unwinding the screw until it returns to its resting position. The screw is small in comparison to the length of the shaft, allowing it considerable movement up and down the shaft and is more like a grub screw. This storage screw is wound into the nut, driven by the fast adding shafts. The storage screw has an internal parrallel keyway. The driving shaft from the adders is keyed and passes through the centre of the screw, the key enabling the driving shaft to turn the screw whilst allowing the screw to travel up and down the shaft, driven by the threads of the nut. If anyone has any ideas on this conceptualisation, I am thankful for any suggestions for improvement. To send email, click on the image and scroll to the bottom of the Photo Gallery page and use the email link there.
I have seen 1940s era Julius Totes and although I have not seen the sort of adder shown at the top of the page, I am certain of the following observation. Protruding from the driven cogs at the front of the adder, that is the ones engaged with the driving cogs underneath attached to the table, are spindles with springs on them. These springs provide the energy to rotate the adding shafts and are the coil springs mentioned above in the extract from George Julius' paper. Following is a further extract form George's paper regarding the winding up of these springs:
The rotation of the nut also is utilised to continually rewind the coil spring which operates the epicyclic gears, and thus ensure a steady driving effort on these gears.
Above the shafts with springs and to the left there are rods that extend from the storage screws. These are part of the mechanisms that sense the position of their respective storage screws, when their respective screw is close to its rest position. This locks the driven equipment of each storage screw when the respective memory is empty and also is part of the feedback path that controls the velocity of the respective driven equipment.
The machine room at White City London
The above image shows the White City Julius Tote Machine Room. It is here to put the image of the GT adder at the top of the page into context, to see what the central processing part of a Julius Tote looks like and how large these systems were. I do not have an image of the Brough Park machine room, however at least this system is also in England. These are only some of the adders in the White City system and does not show all the ancillary equipment panels. Part of the ancillary equipment panels is just visible on the left hand wall however it shows little detail. The adder at the top of this page is a Grand Total adder which means it sums the totals of all the other adders in a particular pool and unusually, this adder totals three pools Win Place and Forecast.
The far left hand adder in the image above at White City, with part of the adder not in the image, is also a Grand Total adder which is for the Place Pool. The sign on the top of the lamplight signpost rising from the adder reads PGT to identify it as the Place pool Grand Total adder. The P is not shown in this image. The adder immediately to the right of this one, has WGT on its lamplight signpost, identifying it as the Win Grand Total adder. When the system is in use, these lights on top of the adders will be illuminated for every adder in use for a race, indicating it is active. Adders corresponding to runner numbers greater than the number of runners in the race, as well as adders corresponding to scratched runners will not be illuminated and remain disabled. The number of runners will be selected on the control panel, which is not visible in this photo. In the two columns of adders on the right hand side, the first adder on the left hand side has a signpost that reads 6W, indicating that this adder is totalling the investments on runner number 6 for the Win pool in the race. The first adder on the right hand row has 6P on its signpost indicating this adder is totalling investments for the Place pool on runner number 6.