Copyright 2006 by Rules |
Summary
Brief historical record is made of calculating machines in use many centuries ago, and of the great advance in rapid calculations by the invention of logarithms. During the past fifty years various mechanical " arithmetical " machines and " instruments " of calculation have been perfected, and are largely used in engineering work, and by those engaged in the preparation of mathematical tables, insurance records, census returns, and similar work. All these machines, however, have been designed for operation and control by a single operator. By means of diagrammatic sketches the essential principles and development of such machines are described.
Of recent years, however, a need has arisen for an adding machine which will pick up and add the records passed on to it by a number of independent operators. Particular applications of this requirement are found in railway ticket printing and issuing, in the recording of sales in large departmental stores, and in racecourse totalisator practice. The paper describes the development of a machine that has been built in Australia capable of meeting such requirements and of recording records received from as many as 1000 independent operators, and at speeds as high as 4000 a second. These machines are capable of both printing and issuing tickets, and at the same time recording the issue of such tickets when issued in great numbers and simultaneously by a number of selling machines.
The machines are equipped with safety gear of various kinds to prevent the issue of tickets without recording same, and generally to ensure absolutely accurate results.
Extract 1
It has been suggested to the writer that members might be interested in a brief description of a mechanical "adding machine," which has been developed and built in Australia, and which differs entirely in principle and in detail from any other form of mechanical calculator.
Extract 2
In all the adding machines so far described, the mechanism
is such that only one addition can be made at one time; in other
words, the machines are not capable of allowing for the simultaneous adding of a number of different amounts. Just as with
the typewriter, the adding machines have all been designed
for control and operation by a single operator.
Of recent years, however, another problem has come forward
to meet which it has been necessary to devise an adding machine
that can add numbers transmitted to it from several operators,
even if those operators all transmit their records at precisely
the same instant of time. In such a case the machine has to
"jump the total."
The requirements may be made more clear by taking a particular case.
On various racecourses throughout the world the law permits
the use of a machine known as the totalisator. This is primarily
a system of machine betting. Tickets are sold from a number
of selling booths on the horses entered for a race, and the total
number of tickets sold on each of these horses, and also the
grand total of all the tickets sold on the race, have to be re-
corded. The ratio between the grand total of all such investments and of the total investments on any particular horse is a
measure of the return which an investor on that horse will
receive if the horse wins the race.
The period during which tickets are sold on any one race is
usually about half an hour, and during that time the total
number of tickets issued on the largest racecourse may reach
1,000,000, which involves an average speed of approximately
33,000 tickets per minute. Actually, the issue is never evenly
divided over the whole of the available time, it being almost
invariably slower at first and correspondingly faster at the last.
Tickets of different values also are generally sold; thus the
ticket of lowest value may be 10s., the next 1 pound, then 5 pounds, 10 pounds, and
so on, up to even 1,000 pounds.
The sales have to be recorded to show the equivalent number
of tickets of the lowest denomination on each horse and on the
grand total. Each 10s. ticket must therefore register one, each
1 pound ticket two, each 5 pound ticket ten, and so on, up to the 1,000 pound
ticket, which must register as two thousand, as it is equivalent
to two thousand 10s. tickets.
The machine to be installed therefore, must automatically
record from instant to instant the total sales on each horse,
and the grand total of all sales, and must display these figures
in such a way that they may be easily legible to the public.
This last requirement necessitates the use of very large counters
or numerators, as the figures require to be legible from a distance
of at least 200 feet.
This latter condition necessitates the use of counter wheels
of large diameter , even as much as 2 feet, and as the speeds at
which they are required to revolve is sometimes great, and the
inertia, however lightly they may be constructed, considerable,
they cannot therefore be started or stopped suddenly. Further,
also, in such installations it is necessary to locate many of the
ticket-selling booths at a considerable distance from the adding
machine, which necessitates the use of electric power for the
transmission of the records from the selling machines to the
recording machine.
Here, again, difficulties arise, as the first requirement of a
totalisator is absolute accuracy, and the use of electric transmission obviously introduces a possible weakness which has to
be guarded against Thus, an electric cable may break, insulation may fail, magnet coils may burn out or short or there
may even be a complete interruption in the supply of electric power to the machine. A complete system of safety gear has
therefore to be introduced, which will only permit of the issue
of a ticket at any booth on any horse if the electric connection
between that selling machine and that horse is in order, and
electric power available.
This may be more briefly expressed by saying that the whole
installation must be so arranged that no ticket can possibly be
issued without its issue being correctly recorded and vice versa,
that no "record" can be transmitted and recorded without the
corresponding issue of a ticket.
One more factor also is of importance. The whole equipment
has frequently to be worked at very high pressure during
selling operations, and the liability of faulty operation of the
ticket-selling machines is thus greatly increased. The design
of these equipments has, therefore to be such as to make them
as nearly " fool proof " as possible.
The foregoing will have made clear the very peculiar and
somewhat exacting conditions that have to be met in order to
ensure a successful solution of' the problem.
The first and most essential factor is the obtaining of a
mechanism which will add the records received from a number
of independent operators. This has been done in two ways. The
first method, which has met with a certain measure of success
in small equipments, depends upon the release of a marble or
steel ball whenever a ticket is issued. These marbles are held
in magazines, and as released they gravitate to one or other of a
group of counters, and operate the counters by reason of their
weight or through some trip mechanism. After passing through
the particular horse counter, they are all elevated by conveyor to
again gravitate to, and operate the grand total counter. Thus,
if twenty sellers at the same instant each issue a 10s. ticket on
one horse, twenty marbles are released, one from each of twenty
magazines and these all gravitate to operate the horse counter.
After completing this work the twenty marbles are elevated by
conveyor to then run through and operate the grand total
counter. If a 1 pound ticket is sold two marbles have to be released,
and similarly ten for a 5 pound ticket, and so on. There are obvious
limitations to this system, but as the originator of a rival
system, the writer does not feel justified in making further
reference to them.
The other system of "collective adding," as it may be called,
depends primarily upon the use of a group of super-imposed
epicyclic gears. Such a group is shown diagrammatically in Figure 8.
Epicyclic Adding Mechanism
Figure 8 
In describing this gear, reference will only be made to the
process of " addition," but it is obvious that the gear is equally
applicable to subtraction. The gear, as shown, is arranged to
receive and add records from six operators, and to show the
total upon the total wheel marked " T," by rolling this total
wheel towards the left, as shown by the arrow.
For convenience let it be assumed that a movement of the
wheel "T" of 1/4 inch to the left represents the issue of one
ticket. The six selling machines are connected to the wheels
"A," "B," "C," and "D," and to the racks "E" and "F"
respectively. The double racks "P," "Q," "R," and "S " are
not connected to selling machines, and are merely portion of the
adding mechanism.
Suppose the wheel "A" to be connected to a 10s. issuing
machine, and to be so arranged that the issue of each 10s. ticket
causes it to roll 1/4 inch to the left, as shown by the arrow. If
the operator of the selling machine connected to this wheel "A" then issues a ticket, the wheel will travel 1/4 inch to the
left, rolling upon the momentarily fixed rack "R," and thereby
moving the rack "P" 1/2 inch to the left. The teeth on the
upper face of the rack "P" will then obviously cause the total
wheel "T" to roll along the momentarily fixed rack " Q," and
thus to travel, as a whole, 1/4 inch to the left. It is seen, therefore, that the movement of the wheel "A" 1/4 inch to the left
will of itself cause the total wheel " T" to move 1/4 inch in
the same direction.
Extract 3
It is obvious, however that the gear as shown in diagram No. 8 could not be used, because the racks would have
to be of impracticable length, and in practice the racks are replaced by bevel wheel. The various records
are then made by the rotation of the wheels A, B, C, D, and hence T about their axes, instead of by the lateral
translation of these axes.
This arrangement is shown in Figure 9 (the corresponding parts in the arrangement shown in Figures 7 and 8 being
"lettered" the same), and its operation should readily be followed, it being merely necessary to change the motion
of translation of the gears shown Figure 8 to one of rotation of the gears shown on Figure 9.
Epicyclic Adding Mechanism
Figure 9 
At this point a number of difficulties arise. Firstly, it would be manifestly impossible to accurately rotate
these gears by means of the impulses received from the ticket-selling machines. Not only would the power
required be excessive and the mechanism very complicated, but the "backlash" in a train of gears such as that described
would give rise to endless inaccuracies. "Power" has therefore to be applied to move the gears, and to be so
arranged that the issue of tickets on the various ticket issuers controls the extent of the movement.
Extract 4
The epicyclic gears, however, must obviously respond instantly
to the records transmitted through them. Thus, if fifty clerks
simultaneously issue tickets on the same horse, the records of
those sales must instantly be picked up by the epicyclic gears,
and as the large counter wheels cannot instantly respond to this
demand some form of "storage" gear has to be introduced
between the epicyclic gears and the counters to "store" up the
records until the counters can he brought up to the necessary
speed to record the sales. But this alone would not be sufficient,
because if a form of storage gear was put in to merely
allow the counter to get up to speed, then if at one instant
tickets were passing at the rate of, say, 2,000 a minute on a
horse, and at the next instant the issue of tickets ceased, the
counters would work up to their speed of 2,000 a minute, and
then required to stop dead when running at top speed. Such
an arrangement would be obviously impracticable, and the goal
has therefore to be so designed as to allow of, firstly, the instantaneous
response of the epicyclic gear to the demands made
upon it; secondly, the storage of these impulses during such
time as the speed of the counters is being brought up to meet
the requirements; and, thirdly, the gradual slowing down of the
counter as it overtakes the registration of the stored-up records.
Go back to the index
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.
Epicyclic Adding Mechanism
Figure 11 
It will be remembered that the extent of the movement of the epicyclic gear
has to be controlled by the value of the ticket issued.
Each epicyclic gear has attached to it an escapement wheel mounted concentric with it, this
wheel being very similar to the ordinary escapement wheel in a clock. These escapement
wheels are themselves controlled by "dead-beat" escapements which are electro-magnetically
operated from the ticket-selling machines. One such group is shown in Figure 12.
Electro-Magnetic escapement
Figure 12 
When a ticket is issued, an electrical impulse is sent through
from the ticket-issuing machine, which, operating the correct
escapement, allows the particular escapement wheel and the
epicyclic gear attached thereto to be moved forward one tooth,
the driving force being the coil spring. By varying the number
of teeth on the escapement wheels the amount of rotation that
accompanies the issue of any particular ticket can be varied.
Thus if the movement of one tooth of a " twenty-tooth " escapement
wheel is arranged to record the sale of a 10s. ticket, then
one tooth on a "ten-tooth" escapement wheel will accurately
record the sale of a 1 pound ticket.
The world's first automatic totalisator
Extract 5
In considering the application of the equipment to meet very
much greater demands, it was apparent that the very large
amount of gearing required under what may be called the Randwick
system would be very costly both to install and to maintain.
A modification of the system has therefore been developed, and
may be briefly described as follows :-
In practice each issuing machine should be run at such a
speed as will allow of the printing and issuing of tickets at the
rate of 100 per minute, this being the maximum speed required.
It has been found, however, that the electro-magnetic escapements
can be installed to accurately pick up and record impulses
at more than ten times this speed. The latest machines have
therefore been constructed with one electro-magnetic escapement
and epicyclic gear for each eight or ten ticket issuers.
In this arrangement, however, allowance has to be made for the
fact that the ten-ticket issuers may all issue tickets simultaneously
on the same horse. Each issuing machine therefore is
equipped with a device which stores up the impulse as soon as
the machine starts to print a ticket, and this stored-up impulse
is picked up by a distributor and passed on to the electro-magnet
at a, speed that is slightly greater than the maximum speed of
the issuing machines. Thus, if the ten issuing machines simultaneously
start to issue a ticket on the same horse, during the
issue of these tickets, the distributor picks up the ten impulses
and delivers them in sequence to the electro-magnetic escapements.
In such a case the electro-magnetic escapement would
make ten beats in the time occupied by a selling machine in
printing and issuing one ticket.
This modification has very greatly reduced the amount of
adding gear required in the machine, as in the new type four, or
at most six, escapements perform the same duty as was previously
performed by the forty escapements in the Randwick type of machine.
This becomes of great importance in considering large equipments.
A unit has recently been built to meet the conditions
of betting on the largest French racecourses. On such courses
it is necessary to allow for the installation of at least 600 selling
machines, and the counters may be required to record the issue
of a million tickets in half an hour.
The unit that has been designed and built will pick up the
impulses from 900 windows selling tickets of various values
between 10s. and 1000 pounds and will add these impulses and record
them at speeds up to 250,000 a minute; that is, at a rate
exceeding 4,000 per second. Such a speed is in excess of anything
that can conceivably be required, but it must be remembered
that although the issue of a million tickets in half an
hour calls, for an average speed of issue of approximately 33,000
a minute, yet the issue of tickets is not uniform, and double this
speed may be required during any particular minute.
Where installations of this magnitude are required, it is
obvious that groups of selling machines have to be installed at
various points on the racecourse, as it is impossible to bring the
crowd to one spot. It is essential, then, that the crowd located
at one group of selling machines should be kept informed of the
state of the betting all over the course. In such cases, therefore,
the impulses from the selling machines all over the course are
transmitted to a central calculating equipment, this central
equipment controls the operations of a number of indicators
which may be located in any convenient positions, one set being
placed near each group of selling machines. Thus, in an equipment
to sell tickets on any of forty-two horses from 900 selling,
booths, there would be 900 individual selling machines divided up
into, say, twenty groups of forty-five in each group. There would
also be forty-two central calculating units, one for each horse,
and a grand total calculating unit. These in turn would control
twenty groups of indicators, each group comprising forty-two
indicators, one for each horse, and a grand total indicator.
The whole installation therefore would consist of 900 printing
and selling machines, forty-three calculating units, and 860
indicator units , the whole system being automatically controlled
and, operated by the issue of tickets from the 900 selling
machines. A unit of this capacity has, as before stated, been
built, and thoroughly tested , and is available here for inspection
by members.
Central Calculating units
Extract 6
As previously mentioned, the whole installation has to be so
designed as to efficiently guard against the effect of faulty
manipulation or accident. Each calculating unit, therefore, is
provided with gear which instantly locks all the ticket issuers
connected to that unit should the electric power fail, or the
driving power for the counters break down, or also should any
essential belt or spring: break.
The gear is so arranged that a breakdown of the calculating
mechanism that is recording the issue of tickets on any
horse only locks the ticket-selling machines against a further
issue of tickets on that; particular horse, and does not interfere
with the issue of tickets on other horses. If the breakdown
is merely temporary, repairs would be effected, and the calculating
" unit" thrown into operation again. If it were serious the
" unit " would be cut out of operation, and a spare " unit"
thrown into gear in place of it. It may be mentioned, however,
that in seven years experience of these machines it has never
yet been found necessary to throw a calculating unit out of
operation.
If you have read this far, you will probably be interested in having a look at some video clips from Andrew Keene's excellent video of a working Julius totalisator
The Calculator Collecting Ring
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