In a company document titled Straight Betting, there is an image of two adder and counter wheel indicator units on page 4. One of these two adder and counter wheel indicator units is of the same type as the one shown in the first image below. The annotation for this image reads Horse Unit of medium sized machine. Associated text indicates that the largest type unit has recorded over 250,000 bets per minute, the medium size records at 3000 bets per minute and the small machine at 1000 per minute. Page 4 of Straight Betting is shown in the last image on this page.
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The photographer's stamp on this photo reads: HALL & CO. Commercial Photographers 20 Hunter Street Sydney
The adding shafts with their epicyclic gear arrangement, escapement wheels and solenoids that are activated by ticket issuing machine pulses are significantly hidden in this image. They can be seen mounted on the two interconnected parallel bars running horizontally the length of the unit about half way up and projecting out of the photo and is the nearest part of the adder. The adding mechanisms are slanted away from the parallel bars at what looks like about 60 degrees from vertical into the photograph towards the counter wheels stopping short of the upper large shaft that runs the length of the unit with the large cog attached to the left hand side.
Having mentioned the upper large shaft that runs the length of the unit with the large cog attached to the left hand side, this is a very interesting piece of mechanical technology. This device was called a Storage Screw however it can be thought of as a type of memory. A good digital computer analogy to this is a buffer memory! There is a second storage screw in this adder near the bottom with almost the same dimensions and orientation. The adding shaft that drives the second Storage Screw is a lot smaller than the upper adding shaft yet is clearer to see as the assembly is vertical rather than slanted away from the viewer.
The need for the storage screws originated from 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. These adding shafts are on the right hand side of this image and drive the storage screw from the right hand side. When it came to large counter wheel indicator displays like the one on the front of this adder, these had to overcome significant inertia. In simplistic terms, as transactions are recorded as increments of rotation generated by the adding shafts, 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, in this case the end with the large cogs, the nut is unwound from the screw at an angular velocity change rate that the slower equipment can accelerate or decelerate at. In the case of acceleration, the slow to accelerate equipment will eventually reach an angular velocity in excess of the storage screw and start to return the screw to its rest position. The screw remembers the rotation generated by the high acceleration adding equipment and is read at the other end at the slower lagging velocity of heavier equipment until acceleration ends and the heavier equipment reaches an angular velocity greater than the screw.
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.
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 second page of the Photo Gallery by clicking on the image, scrolling down to the bottom of the first page of the Photo Gallery clicking on the next page button of the navigation bar then scroll down to the section mentioned. There are also images of engineering drawings of the adding shafts and escapement assemblies in this section.
I have chosen this image to write about the mechanism that locks the driving gear as this image has the most prominent view of this part of the machinery. Following is a short extract from a Paper George Julius presented to the Institution of Engineers Australia in 1920. This extract relates to the storage screw:
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.This locking mechanism George mentions, can easily be seen in this image. Looking on the left hand side of the adder at the top large cog, which has the upper storage screw at its centre, come left past the left hand side mounting frame of the adder and you see a rod projecting left from the storage screw. This is part of the storage screw position sensing mechanism. At the point where the rod disappears into the storage screw, there is a bracket attached to the left hand mounting frame of the adder, which extends upwards and left at 45 degrees to the storage screw. At the end of this bracket is a hinge. Attached to this is a moving arm consisting of two metal strips which project downwards to the drive pulley for the gear that drives the large cog, that we started with. At the bottom end of this arm, is a projection that engages with a stop on the shaft that drives the cog that turns the upper large cog that rotates the storage screw nut. This projection on the arm and stop are hidden behind the drive pulley. This is the locking mechanism that George is describing. Once the storage screw starts to move as a result of transactions from the adding shafts being recorded, the first thing that happens is that this arm moves to disengage the lock and allow the drive pulley to rotate the large cog which turns the nut part of the storage screw. There are some video clips in the Video clips of a working Julius tote chapter of this website that show this release mechanism associated with the storage screw working. The adders in the video clips are more modern than the one in this image and are larger, being mounted on tables. The audio track on these video clips clearly conveys the clanking sound of these locks being disengaged. The clips that show these locks in operation are titled The forecast pool adders and Place GT and forecast adder internals. These can be viewed here.
Inside the drive pulley in this description, there is a clutch which slips when the locking mechanism is deployed. To the left of the pulley before reaching the end of the shaft on which it rotates a spring is visible. When the pulley is rotating this spring is wound. The energy to rotate the adding shafts comes from this spring. This is an important concept as the drive to the pulley being discussed is continuous and betting is start stop and erratic. There has to be a means of disengaging from the constant drive when no betting is taking place.
A second extract from George's paper mentioned above reads:
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.At the end of the rod that projects out of left hand side of the upper storage screw, which is part of the storage screw position sensing mechanism, there is a hinged arm projecting down from a mounting above, which has a hinged tip at the bottom end making contact with the left hand end of the storage screw position sensing rod. I think this is part of the variable speed friction gear that George has described. I have never seen one of these adders, however from this photograph and the following photograph in the Photo Gallery it is possible to deduce an overview of how it worked. To find out more, go to the next photograph in the Photo Gallery which shows this adder from a different angle. Click on the image then click on the next image thumbnail.
Page 4 Straight Betting
The Horse Unit of medium sized machine mentioned at the top of this page is shown in the bottom left picture in the image above. This picture shows the front view, of the adder and counter wheel indicator unit shown from the rear in the image at the top of this page.
The note inside the top left text box in the image above, to the left of the largest type machine picture reads:
A machine of the large type would only be installed on courses doing an extra large business. The unit (No. 1) would not be seen by the public, but sets of indicators, in appearance like the medium size unit, would be erected at various positions.The note in the top right text box in the image above, on the right hand side of the largest type machine reads:
These indicators would be controlled by the main machine and would display at any moment the actual state of the betting.
The horse unit of the largest type has recorded accurately over 250,000 bets per minute (see page 11). The medium size records at the rate of 3000 bets per minute, and the small machine at the rate of 1000 per minute.You can view an image of the largest type machine on this website, which is identical to the one shown in page 4 of Straight Betting above. To view this, click on the image at the top of this page and scroll up to the Photo Gallery section titled Randwick Racecourse Sydney New South Wales, then scroll down again and select the image thumbnail with associated text starting This image shows an ornate early large system adder.