Wonders of World Engineering

 © Wonders of World Engineering 2015  |  site map  |  info@wondersofworldengineering.com

Millions of coins are used annually to operate “automatic” machines for issuing goods, tickets, gas or electricity, or for entertainment purposes. Many of these devices are electrically operated and certain ticket issuing machines not only print the tickets but also deliver the correct change


THE amount of pennies and silver coins that pass through the slots of “automatic” machines annually in Great Britain cannot be computed. Moreover, it is increasing with the growing variety of machines whose mechanism is freed for operation by the insertion of a coin. The machines include meters which allow a measured quantity of gas or electricity to pass, and these slot or prepayment meters receive millions of coins in a year.


Other slot machines are attached to telephones in public call-boxes; there are door locks and turnstiles which are opened by the insertion of a coin, and machines which supply postage stamps, cigarettes, matches, chocolates, sweets, tickets, change, grocery, fruit and various other articles. Other types are automatic weighing machines, of which some print tickets stamped with the date and the weight and others announce the weight by means of a sound record. Another group of machines affords amusement, some of these being operated by small electric motors.


Although the slot machines have been improved and developed enormously during the last few years, the idea is ancient. The first slot machine is believed to have been installed in Egyptian temples centuries ago for the purpose of supplying sacred water. The pilgrim or worshipper put the coin into a slot at the top of the machine and it fell on to a lever balanced on a fulcrum. The coin tipped one end of the lever so that the other end, to which was attached a vertical rod, was raised. The rod was submerged in water and at its lower end was a valve which fitted as a lid on the top of a small chamber. When the rod was raised by the falling coin the water flowed into the chamber and out through a pipe. The weight of the rod pulled the lid down again, stopping the flow of water.


Automatic machines which supplied snuff, or sufficient tobacco to fill a pipe, were used in Great Britain early in the last century. About fifty years ago American inventors concentrated on devising slot machines, and even then all-automatic shops were contemplated. Some countries favour the automatic restaurant, where stands of machines provide the customer with a varied meal complete with drinks. This type of restaurant has been introduced into Great Britain, but has not achieved popularity. This difference in the success of similar equipment in two countries is due to a variety of factors, including the psychological one, for the British reaction to the slot machine is different from that of the American. The commercial success of an automatic machine depends largely upon the mental attitude of its customers.


In the United States inhabitants of large cities accepted the machine as an automatic salesman on duty at all hours, but in Great Britain this attitude is largely the result of laws restricting shopping hours and of improvements in the machines. Although cigarettes have been sold singly from machines for many years, these machines were regarded merely as a convenience. Then an Act was passed compelling tobacconists to close at stated hours, and there were installed machines supplying cigarettes in packets of tens and twenties. Before these machines had become numerous there was a tendency for smokers to tempt shopkeepers to break the law by selling cigarettes after hours, but machines are now so extensively used that they protect the shopkeeper from this annoyance. They meet the need of the person who regards a closed shop door as a barrier to his convenience, and they meet with the approval of social workers who are trying to secure more leisure for shop assistants.


TICKET ISSUING MACH I NE of the type extensively used in London underground stationsTicket printing and issuing machines are now extensively used by the London Passenger Transport Board. These machines issue tickets of values ranging from one penny to one shilling; some of the latest designs are equipped with devices for giving change.

Machines worked by copper coins can be operated by inserting either halfpennies or pennies, or both. The coins can be put into the machine in a bunch haphazardly. If the passenger wishes to buy more than one ticket he can insert the total money for the number of tickets simultaneously. He puts in the money and the machine will sort and count it and deliver the tickets. The mechanism is worked by a ¼ horsepower electric motor, set in motion by the coins, which make an electrical contact. The motor is controlled by a clock device which switches it off in from six to eight seconds. Formerly the machines were operated by a continuously running motor. When there is a line of passengers the operation of the motor is continuous, as the coins may be thrust into the machine by one passenger after another so rapidly that it is not necessary for one passenger to wait for the previous passenger’s ticket to be delivered before putting in the coins. A queue can thus move steadily forward, and the speed of a change-giving ticket machine can be as much as thirty tickets a minute.






TICKET ISSUING MACHINE of the type extensively used in London underground stations. The machine prints the tickets as soon as the necessary coins have been inserted. Change and rejected coins are delivered in the receptacle halfway down the machine.






Change-Giving Device


Each machine prints its tickets from a plain roll of paper which can be replenished in half a minute or less. The paper tickets cost less than cardboard ones, and they eliminate the necessity for keeping and checking a stock of printed tickets which have a definite value immediately they are printed. The printing can be done on one or both sides of the ticket, and the date and serial number can be included. The blank roll of ticket paper provides from 2,000 to 4,000 tickets, according to the length required for each ticket.


The change-giving device does not slow up the operation of a ticket machine. On machines for tickets up to and including fivepence, change-giving facilities are generally provided for the insertion of a sixpenny piece or a shilling, so that the change is issued with the ticket. For values from sevenpence to elevenpence the ticket can be obtained by inserting a sixpence and coppers, a shilling or a florin, the appropriate change being given by the machine.


Copper and silver coins are automatically stored in the change-giving hoppers of the machine so that after the insertion of a few coins to act as a “float”, no further attention need be given to the change-giving facilities.


The machine is enclosed in a sheet-metal case, the front and back of which can be opened. As the entire mechanism is of unit construction it can be pulled out of the case on a track provided for that purpose. The paper roll is mounted in a clip fixed in the base of the machine. The paper passes from the roll through the printing unit. Should the paper break or run out, the entire machine is automatically switched off and any coins inserted afterwards are returned. If necessary a device can be attached to ring a bell to warn an attendant.


The printer is simple, robust and of the rotary type. The number of printing rollers varies according to the amount of typematter required on each ticket, and whether it is to be printed on one or on both sides. If necessary the printing rollers can be removed and replaced by others in a few seconds. A counter on the printer box records the number of tickets issued, and this counter cannot be altered when the printer box is out of the machine except by completely dismantling it. As the whole is sealed it cannot be opened by unauthorized persons without detection.


OPERATED BY ELECTRIC MOTORS, the “Steer-a-Car” is a machine for entertainment purposes




OPERATED BY ELECTRIC MOTORS, the “Steer-a-Car” is a machine for entertainment purposes. Insertion of a penny causes rollers to move a waved band on which strips of metal represent the sides of a road. The large steering wheel manipulates the model car and the object is to keep the car between the moving metal strips.






The coin mechanism which operates the printer is also of unit construction. On the change-giving ticket machines there are three slots, one for sixpences, one for shillings and one for coppers. The copper insertion point is an aperture slightly in excess of the diameter of a penny, which enables a number of pennies and halfpennies to be dropped in at the same time. This is known as a “bunch hopper”.


When coppers are dropped into a bunch hopper they switch on the mechanism and are tested and counted. They fall upon a disk which is revolved by an electric motor and bevel gearing. They are caught by studs on the face of the disk and are carried round in a counter-clockwise direction, moving a trip lever as they pass through. The trip lever imparts a partial rotation to a ratchet wheel, which is part of the coin counter, or counter wheel. The amount of movement of the counter wheel depends upon the diameter of the coin, a halfpenny moving it half the distance of a penny.


The rim of the counter wheel has teeth set at intervals, each tooth being spaced in accordance with the value of the ticket. In a machine for fourpenny tickets, each halfpenny moves the disk one-eighth of the distance between the teeth and each penny one-quarter of the distance, so that it is immaterial whether four pennies, eight halfpennies or any variety of pennies and halfpennies to make up fourpence is dropped into the bunch hopper.


Rejected Coins


When the disk has turned the distance ensured by the value of the coins, the tooth engages a pawl attached to a connecting rod and forces it downwards. In turn the connecting rod operates a clutch release pawl which engages a clutch disk. This is part of the first actuating wheel which operates the printer by means of gears and a driving shaft. The strip of paper or cardboard passes between the pressure rollers, is printed, cut by a knife on a cutting roller and delivered to the passenger.


Thus the tooth on the counter wheel starts the printing and delivery of one ticket when the last coin has passed the trip lever. The coins pass on down a chute to the cash till in the bottom of the case. If a coin is bent or battered it will not be retained by the studs on the disk, and will slip out and down the chute for rejected coins.


In vending machines delivery is effected by various types of mechanism. In these machines the coin-selecting mechanism is extremely sensitive, so that the coins are tested. One apparatus subjects each silver coin to no fewer than ten distinct tests in less than two seconds. Each coin is tested for diameter, milling, weight and thickness; magnetic or ferrous disks and perforated coins are rejected. A simpler type of selector tests copper coins. Only when the coin has passed the tests does it fall to the till and operate the delivery mechanism.


The modern vending machine generally contains an electric clock or an electric sign, and is also lighted by electricity. The lighting is controlled by an automatic time switch in the base of the case, and this switches the current off at any predetermined time. The case is of stainless steel, the glass is armour-plate glass, and the mechanism is arranged to swing outwards for inspection, an inspection light aiding adjustment at night. The door covering the columns is hinged to open upwards to provide shelter when the machine is being filled, and only one key is required to open all doors.


Some machines are built in the door of a shop, to save space. The vending machine is built into the woodwork of a new door and the entire door replaces the ordinary door of the shop. Another type of machine is placed on the counter of a shop or on the desk in the reception hall of an hotel, and is operated either by coins or by the assistant. It is not a change-giving machine.


Huge sums of money pass through the slots of prepayment gas meters. There are various types, including one which is available for either a penny or a shilling, to prevent the householder from being inconvenienced should he not have the one coin available. The meter works in an analogous manner to the steam engine, the pressure of the gas operating the recording mechanism. Instead of pistons there are two leather diaphragms made from the skin of an animal. Each diaphragm drives a D-type slide valve.

The meter is divided into two sections, upper and lower. The upper section contains the valve gear driven by the diaphragms and is connected to the recording mechanism, and also contains the prepayment mechanism. The lower section is divided into four measuring chambers, two opposite each diaphragm. While gas is flowing into one diaphragm it is flowing out of the other, so that there is no interruption in the supply and the flow. When a coin is put into the slot it presses down a lever on to a toothed wheel. The householder turns the wheel from the outside and the rotation operates a cam. If a penny is inserted the drive to the cam is direct, but a shilling operates another toothed wheel geared 12 to 1, so that a shilling turns the cam twelve times as far as a penny. This cam operates the valve which allows the gas to pass. When the amount has been delivered the cam, which is worked by a drive inside the meter, shuts the valve.


Attention to dieting has benefited the makers of coin-freed weighing machines. Some of these register a person’s weight, others in addition provide a card on which the weight and date are printed, and another type speaks the weight. Charles Ahrens, who invented the “talking weigher”, makes machines to weigh at 1 lb intervals from 7 lb to 280 lb (20 stone). The vocal part of the mechanism is a sound record of the usual disk shape. Instead of the sound grooves being continuous as in an ordinary record, they are broken by a gap which extends from the centre to the rim of the record, this gap marking the beginning and the end of the grooves in the record.


OPERATED BY COPPER COINS, this mechanism is used in ticket-issuing machines





OPERATED BY COPPER COINS, this mechanism is used in ticket-issuing machines. The coins are caught by studs on a revolving disk and are carried past a trip lever. When the necessary number of coins has passed, the printing mechanism is set in motion and the ticket is delivered. To show the path of the coins, the front part of the machine, including bunch hopper and testing mechanism, has been removed.






When a person steps on to the platform of the machine the momentum at first causes a gramophone needle to wobble over the blank gap in the record, but the needle steadies. Then the penny is inserted, and this closes an electric circuit and starts the motor which revolves the disk once. As the disk begins to turn, the needle falls into the sound groove corresponding with the weight measured by the weighing platform. The record turns at about half the speed of the usual gramophone and this enables the reproduction into sound through the soundbox to be slow enough for the hearer to understand it clearly. Disks are manufactured with sound tracks in many languages.


In weighing machines which print the weight on a cardboard ticket, type is mounted on the rim of a wheel. The wheel turns in accordance with the weight of the person on the platform of the machine and pauses under a stamping device which presses a ticket on to the type and discharges it down a delivery chute.


Many ingenious machines are made for amusement purposes. Most of the newer models are worked by electricity. The general principle of these machines is that when the penny is inserted it closes an electric circuit which enables current from external wiring to flow to electric motors of one-sixteenth horse-power in the machine. These work the mechanism and after an interval release a catch which allows the penny to drop into the till, breaking the electric circuit.


One machine of this kind is the “Rotary Skill Merchandiser”. It consists of a glass-topped wooden cabinet divided into upper and lower compartments. In the upper compartment is a disk which is made to revolve. Articles are placed on this revolving, round platform. In the centre is an opening leading to a chute. A rod actuated by a motor is arranged to pass across the revolving table from the outside edge to the centre, so that if an article is in its path the article will be pushed into the hole and so down the chute. The lower compartment contains the mechanism. On one side of the machine is a lever and the slot and coin guide.


The table is set in motion by an electric motor, and a coin is placed in the slot and passes to a catch which is operated by the control lever connected with the top of the cabinet. This lever operates the rod which passes across the table. When the lever is pressed a catch is released and the penny falls to a stop where it closes an electric circuit. The current passes to the motor which operates the rod by gears, and the rod is pushed across the table. At the end of the rod’s sweep the catch holding the penny opens, releasing the coin, which falls into a receptacle, and the circuit is broken.


APRINTING MECHANISM of a ticket issuing machinenother machine is called the “Pile Driver” and includes a drum containing twelve receptacles in which articles are placed. The operator inserts a coin and then pushes a lever and tries to time the working of the “pile driver” so that it descends and pushes an article out of a receptacle into a chute.


Other machines are operated by rollers turned by electric motors. The “Steer-a-Car” comprises rollers on which moves a waved band that represents a winding road, strips of metal marking the sides of the road. The model of a motor car guided by a metal cross-piece is controlled by a steering wheel fixed to the machine. When the mechanism is started the road travels, and the operator tries to manipulate the miniature car in such a way that it does not touch the sides of the road.


Large numbers of machines are operated mechanically and not electrically. Other machines are operated mechanically, but have devices for recording scores by electricity.





THE PRINTING MECHANISM of a ticket issuing machine is set in operation when the necessary number of coins has been inserted. A strip of paper from a roll moves forward between printing rollers and is automatically guillotined and delivered.





A walk on a seaside pier will indicate the fashions in amusement machines. At one time they were built of iron and were painted in gay colours; then fashions changed and electrically-lighted machines in handsome wooden cabinets were introduced with metal parts heavily plated. Every season new machines are produced. The engineering skill which has produced such a wide range of automatic coin-freed machines is of a high order.


These machines present some problems to the designer which are not encountered in other branches of engineering. Many difficulties had to be overcome to obtain mechanism that could be put into operation by the insertion of coins and would reject spurious coins.


The fact that the coins in circulation vary considerably in weight, thickness and composition prevents the fining down of the coin selector to narrow limits, and a margin therefore has to be allowed.


Many inventions have been made to test silver coins. In one the coin is subjected to an alternating magnetic field produced by a thermonic valve oscillator. The change in frequency of the oscillator due to the currents created in the coin is compared with that produced in that oscillator or a similar one by a standard coin, and if there is a difference the coin is rejected.

Machines have been made to be operated by the twelve-cornered threepenny piece.


[From part 51, published 15 February 1938]



You can read more on “Ticket and Change Machines” in Railway Wonders of the World.


Automatic Coin Machines