Title: The sorting office goes automatic
Pages: 38 - 41
Author: Richard Carr
Text: The sorting office goes automatic
by Richard Carr
Last month a postal code, designed to use automatic letter sorting equipment, was introduced in Croydon, and in May a similar system was started in Germany, which includes the rotating distribution machine shown in the picture on the left. The author describes how these developments will revolutionise/he handling of mail.
At the end of last year, the Postmaster General, then Anthony Wedgwood Benn, opened an exhibition in London (DESIGN 204/69) which demonstrated the first automatic letter sorting equipment to be developed in Britain. The equipment had in fact, been undergoing tests for some time, and experiments had also been carried out on the use of a postal code at Norwich (DESIGN 123/42-44). Last month, the code was put into operation at Croydon - the first stage in the adoption of the code, and its equipment, in about 20 areas in Great Britain during the next two years.
Eventually, the system will be used throughout the country, and letters will then pass through human hands only when they are collected from the postbox and code marked at the despatch station, and when they are delivered to people's houses. At all other times, the letters will be handled by machines, which will sort them out ready for transit, and then finally sort them again down to a large firm, or a group of houses, on the postman's round. A similar system was also put into operation at Pforzheim, in West Germany, last May. Together, they mark the beginning of a revolution in the world's postal services.
In Britain, the first moves towards the mechanisation of letter sorting were taken in the 1930s, when two Dutch Transorma machines were installed in Brighton, where they are still in use today. These machines have entirely mechanical controls, but a keyboard (using one hand only) gives the operator a choice of up to 300 different destinations, so that within this limit the letter can be sorted and stacked automatically. Although useful, these machines did not fulfil all the British requirements. The GPO carried out some initial research into automatic mail handling systems before the war, but in 1946 recommenced the work at Dollis Hill and set up a postal engineering development unit at Mount Pleasant. It is these two units which are responsible for the design of the equipment now being produced by British industry for the GPO.
Development guide lines
From the start, there were several principles which guided the equipment's development. The first was that the safety of mail is paramount, and that overnight delivery should be maintained. Then, with regard to the sorting machines, it was laid down that the operator should not touch the mail; that he should be able to use both hands for the keys, not one hand only as with the Dutch machines then in use; and that he should be able to work at his own pace. (This was also contrary to the design practice on other concepts of sorting
machines. which acted as pace makers.) And finally, the postal unions were consulted at every stage.
The human approach was reinforced by the decision to call in ergonomists and other experts to give advice on seating positions, letter viewing arrangements and keyboard dimensions and layout.
In the development of the sorting machine, the first prototype was fed by six men working independently, whose output was collected on to a set of conveyor bands having a total of 144 selections. The collecting boxes thus handled mail from six different sources. The main problem facing this machine was how to ensure an even flow of mail and avoid interference somewhere along the system, and this became so difficult that it was eventually decided to develop a machine with one operator only.
A public code
At the same time, it was also decided to replace the sorting machines' code, which had to be learned and remembered by each operator, by a public code, developed at Dollis Hill from 1950 onwards. This is the code which has been tried at Norwich and is now operating at Croydon: it consists (usually) of six characters, the first three of which represent the town or district, and the next three the actual street, or part of a street or an individual firm, where the mail is to be delivered. This is the code which the operator, sitting at a coding desk, copies on a typewriter keyboard, and the machine translates this action into a set of code-dots on the envelope which all sorting machines can follow.
At Croydon, for example, the following (fictitious) address, 500 North Street, Croydon, is given a public code CRO 9LA where CRO stands for Croydon and 9LA for a part of the postman's round. The public code itself is thus an integral part of the address and should be added to the address written on the envelope in exactly the same way that one does a postal district address. In larger towns, the code will represent the district. For example, a letter sent to London SW1 might have as its code SW1 9LA.
Besides the automatic letter sorting machine, the GPO system has two other elements. First, because both packets and letters are accepted in a pillar box, there is a segregator which separates them at the despatch office, distinguishing between letters which can be handled by automatic machines, and packets (and parcels) which cannot. The development of segregators has proved a very difficult task, but a number are now in use and others are under construction. continued on page 40
The second element is the facing machine, which ensures that all letters have their address facing the same way. This is essential, first for cancelling the stamps (also done automatically by a facing machine); second, to allow the coding desk operator, and the machine itself, to read an address (or machine code). All subsequent operations maintain this 'facing' so that the postman can deliver his mail without further re-orientation.
A number of different techniques, including optical scanning and the use of magnetic and conducting materials in stamps, were tried in the development of the facing machine, and proved only partly satisfactory. Optical scanning, eg, is difficult because of the number of variations (and sometimes the similarities) in the colour of stamps and envelopes. The technique now adopted uses non-toxic phosphorescent lines printed on the stamps (although optical scanning is used as well). These lines are completely invisible, but when illuminated by a U/V light, a signal can be detected by the letter facer as the letter goes through the machine. If the public code is omitted from the address, the coding desk operator can extract the destination town name and the letter will be sorted by machine for that town. On arrival, a second coding desk operator will extract the street name for sorting to the delivery postman.
The German system
Like the equipment in Britain, the system introduced at Pforzheim is the result of development begun before the last war, which has gradually been refined so that it now includes photoelectric cells to
regulate the flow of letters, and mimic diagrams to show what is going on at each stage of a letter's progress.
The equipment handles approximately half Pforzheim's incoming and outgoing mail, ie, 200,000 letters a day, and distributes the former to 85 local postal districts, 36 post offices and branches, and just under 2,000 post office box holders. The outgoing mail is sorted in two stages, going to about 1,150 local and regional centres. In both cases, the sorting and distribution process is divided into three stages, known as coding, culling and sorting.
Seven coding stations
The process begins by aligning the letters for reading and, where appropriate, cancellation, and then feeds them into an input storage which serves seven coding stations. At these stations, the letters are fed to a clerk who types on them a postal area for outgoing mail, and the first four letters of the street name on incoming letters. The typing is done using magnetic or fluorescent ink, which is read by the machine itself.
After letters have been coded, the next stage is their culling, during which they are sorted into a number of destination routes. In fact, at this preliminary sorting stage, a number of letters can be channelled off to their final destination. The rest are directed to storage hoppers which feed the sorting machines, each of which caters for a particular area, or set of destinations.
Each of the sorting machines consists of 100 bins which slowly rotate and are fed from the storage hopper via a segregator which determines which bin each letter is to go into. This is controlled by
A British automatic letter facing machine, which can also be used for cancelling stamps. It handles up to 20,000 letters an hour, and then feeds them to the sorting machine operators.
The operator of this British machine retypes the public postal code which is read by the letter sorting machine behind. The ergonomics of the keyboard, chair and letter alignment have been very carefully considered.
the magnetic code typed on the letter at the coding stage, and by a central electronic coding unit. The coding unit operates in cycles and during each cycle it serves all coding stations or sorters, answering each interrogation between a coded letter and each part of the system within milliseconds. Finally, the automatic letter sorting system at Pforzheim has been integrated into a conveyor network consisting of 23 belts and 6 elevators which carry unsorted letters to the sorting machines, and thence to despatch and distribution points.
In opening the exhibition of British equipment last year, Mr Wedgwood Benn stressed the enormous export markets which could develop in this field, and here, of course, British manufacturers will face competition from Germany and elsewhere. When this happens, the equipment will be judged, not only on its reliability; flexibility and cost, but also on its appearance; and on this account, the equipment at Pforzheim is vastly superior. Developed and built entirely by Siemens AG, Munich, it shows that the company realises the importance of having both ergonomists and industrial designers in its own design office.
The British equipment, on the other hand, is all too clearly the work of engineers who have not yet considered the appearance of individual machines, or the way in which they relate to each other. However, now that the development work has been done and the machines are being put out to tender, it is to be hoped that those who manufacture them will take these matters into account.
A view of the German version of the sorting machine operator's position, showing how the machine has been neatly encased. It is the kind of detail which Rritich manufacturers must now consider
The modular magnetic core matrices which govern the German sorting equipment. They are extremely flexible, and can be used for other postal work without the basic design concept being modified.
The roller conveyor system used on the British letter sorting machine. The conveyors are synchronised with the operating mechanism, so that the pigeon hole door opens the moment the right letter reaches it.