THE HISTORY OF THE ELEVATOR INDUSTRY

By GA MacWhirter MD of the Otis Elevator Company Ltd, Johannesburg - The Certificated Engineer March 1973

All industries have a history and the lift or elevator industry is no exception. Its development as a mechanical and electrical problem is the one which concerns us here - but nevertheless its impact on the social and economic life of our cities cannot be ignored.

In the 1850s all cities had a population density based on the maximum practical height of buildings at that time. Generally, four floors above the ground were about the limit. Rentals decreased with height and there was, therefore, no reason to build higher. If the elevator had not been developed our cities would be very different places, and their spread would have made our social and business life very difficult.

Although the industry as such only dates back to the middle of the last century, mechanical methods of lifting people and material go back much further than that.

The ancient Egyptians, fine builders that they were, utilized various means of roping and ramping to move blocks of stone in shaping the great Pyramids.

The pulley, the key-stone of all lifting appliances, has no date in recorded history and certainly goes back more than three thousand years. Assyrian relief of the 8th Century B.C. shows its common use in the Middle Eastern Civilization.

No one knows when the first man-carrying hoist was invented Aristotle (384-322 B.C.) and Archimedes (287-212 B.C.) both mentioned hoists in their writings.

St. Paul's friends probably used such a device when they lowered him to safety from the walls of Damascus.

The Romans had tread wheel mechanisms and water-driven passenger and freight hoists. In the ruins of Pompeii, buried in 79 A.D. by an eruption of Mount Vesuvius, a wire cable (of bronze wire) has been found.

Among the records handed down from the monasteries of medieval times are many drawings of hoists for the transportation of men and supplies. One of the best known was in the Monastery of St. Barlaam at Meteroa in Greece. This structure was located on a pinnacle 6S meters above ground level, and the hoist was the only means of access.

The oldest known hoisting "machine" still in existence is in the Abbey of Mount St. Michel on the French sea-coast. Built when the abbey was restored in 1203, this hoist was raised and lowered by a rope wound on a drum, and "the motive power was furnished by a donkey walking within a large wheel. The wheel is still intact, although no longer in use.

In the middle of the seventeenth century, a resident of Paris invented the "Flying Chair”, which was cranked up and down by a servant. A hoistway was used with this device, and a cage was raised and lowered by a rope passing around to a drum and down to a lead counterweight. Similar hoists are an aid to have been installed in Windsor Castle for Queen Anne in 1713 and for Maria Theresa, Empress of Austria, in 1780.

Counterweighing the load to be lifted provided greater lifting capacity and required less muscle.

Elevatoring took its quantitative leap forward during the English Industrial Revolution when power was substituted for muscle. The expansive power of steam, recognized by Hero of Alexandria in 150 B.C., had been a plaything until 1650 when the second Marquis of Worcester employed it in a water pump to raise supply in his castle. Gradual improvements over the next century built a foundation for the industrialization of England; then Germany and France. When James Watt finally developed the steam engine into a modern machine, it wasn't long before men were trying to find ways in which to make it lift materials as well as themselves. A Burgomeister Donnell is recorded an inventing a mechanical mine hoist about 1800 in Germany, and a power-driven elevator named the "teagle" was described as operating in an English factory in 1835. It can be assumed that these were actuated by steam engines.

The impact of increasing land values was beginning to be felt. The cheaper rents on the upper floors could not compensate for the energy required to climb stairs - so the caretaker lived on the top floor. The trigger which fired the public imagination and public demand were provided by an inventor who demonstrated his device in the year 1853 at the New York Crystal Palace. The New York Tribune reported: "We may well allude to an elevator or a machine for hoisting goods, exhibited by Mr. E. G. Otis of Yonkers, which attracts attention by the apparent daring of the inventor, who, as he rides up and down on the platform occasionally cuts the rope by which it is supported".

No longer did a person riding on an elevator take his life into his own hands. Should the hoist rope break, as it apparently often did in those days before scheduled maintenance, safety catches would engage iron racks attached to the face of the guide rails.

Twenty years later an Austrian, Anton FreissIer, developed a safety device that replaced the catches and racks with serrated cams operating on the smooth surface of the rails.

These devices were satisfactory for slow speeds, but more was required. Overspeed had to be catered for and the governor rope operated safety device appeared. Speeds increased and an instantaneous safety d vice was no longer practicable, so the gradually applied safety was developed. This gave scope for many ingenious variations all designed to limit the rate of deceleration to one which damaged neither the passenger nor the equipment.

All were and are governor operated - the basis being an endless rope attached to the elevator car and passing over the governor which trips at a pre-set speed. One version had the endless rope attached to a rope on the car which unwound a drum located beneath the car and by the wedge, action applied the scissor jaws to the rails. Others used today, are instantly applied, but the pressure is controlled by compression springs.

The drum version obviously applied pressure increasingly with car movement: the governor rope being retarded by a rope clamping device on the governor.

The spring-operated device is designed to slide varying amounts depending on the contract speed of the elevator. In South Africa, this industry is kept to the standard most effectively by the Department of Inspectors of Machinery, and they see that all safety gears are tested annually.

This mechanical device in various forms has been part of the industry since the mid-19th Century, and people today are far less conscious of the fact that it exists than they were fifty years ago. Perhaps that is some proof of its efficiency.

Safety gears are of course fitted to the car frames and sometimes when required by site conditions, to counterweights.

They are applied to the guide rails which ultimately support the load. Rails, therefore, have a function additional to guiding the lift in the shaft.

The story of lifting is one of the power eras. We have already touched upon that of man and animal. The subsequent eras involving steam, hydraulics, and electricity came in such rapid succession after the middle of the last century, that the elevator industry was hardly able to absorb one innovation before it was supplanted by another.

When the steam engine was brought to the United States about 1850, it was in the form of a central power plant that drove all the machinery in a mill or factory through a long "line shaft". Whatever had to be driven was activated by means of belting between its pulleys and those on the line shaft. Hand rope control was in vogue at this time, and a tug would shift belts and change the direction of travel. Thousands of these elevators were driven by remote power. A substantial installation of 16 freight elevators in a large Boston warehouse is recorded in 1857.

A significant improvement was made about 1860 when Otis Brothers & Company brought out an elevator machine having its own independent steam engine. The Otis "Patent Hoisting Engine" pioneered in 1862, had two vertical cylinders situated below the crankshaft upon which was keyed a small pulley. A flat belt from this drove the winding drum pulley. The company shortly thereafter used the same cylinder arrangement to drive a worm and gear in its introduction of the direct coupling.

As the elevator steam machine was being made compact in America, a type of equipment was born in France, which would usher in the era of the hydraulics a decade later. In 1867, Leon Edoux, probably his nation's most successful elevator inventor and manufacturer, exhibited what was termed "the first secure hydraulic elevator" at the Universal Exposition in Paris. It was equipped with an apparatus that permitted stopping at any point and automatically regulated the car's velocity. The simple, direct-action hydraulic elevators enjoyed popularity for many decades and at their peak, cars were being pushed 25 stories by pistons sunk into the ground as deep as the hatchways were high. In seeking a way to circumvent expensive excavation, C. W. Baldwin of Chicago designed a type of elevator in 1872 which was to revolutionize the industry - the indirect action hydraulic. The first uniquely American concept in the field's history, the rope-geared system of hydraulic operation was so basically simple and meritorious that by 1880 it had been embraced by virtually all American manufacturers. Through the use of reeving and sheaves, the roped systems developed reductions up to 12:1. As a matter of expediency, the full attainable speeds could never be used and were limited to 200-230 meters per minute, the maximum an operator could control.

Often operating under 800 pounds’ pressures, developed by steam-driven pumps, the indirect-acting hydraulics to k every conceivable shape and form; some were vertical; others horizontal; some pushed while the man pulled, and there were models that acted through spur gears instead of sheaves. The new breed was silent; it could attain high speeds, and the absence of a winding drum enabled the car to be carried by more than one or two cables. Fine valve engineering assured a sensitive control and smooth operation, and in many instances, a large investment in pumps, tanks, and boilers. I eliminated the use of city water. When the building slump ended in 1878, the emphasis was upon hydraulics. The steam era had lasted about 25 years and that of the pistons would fall roughly into the last 25 years of the century.

Despite the success of the rope-geared hydraulic in America, this type was not a favorite in Europe.

Aesthetically, the Continentals frowned upon buildings much over 10 stories high (and continued to do so until a few years ago) and the well-drilling for this relatively short travel constituted no great problem. The European manufacturer's innate distrust of cable support coupled with his American counterpart's rapid and finished development of this elevator art form contributed to the foothold which the latter gained in the vertical transportation markets throughout the world during this period.

Undoubtedly these water-driven brutes played a tremendous part in the development of the nation at a critical point in its city-building life, but the question of their future was soon to become academic. Actually, their nemesis had been invented in 1880 as an experiment by the eminent German electrician, Werner von Siemens, who exhibited a car driven by a motor and worm gear at the Industrial Exposition at Mannheim. His radical direct-connected system was not to represent the direction taken by the electric elevator in the beginning; the first use of motors paralleled that of the earliest steam engines - remote belt motivation. Mechanical gear reducers were indirectly driven in those days, as were the pumps feeding the popular hydraulics.

William Baxter, Jr. is said to have built the first American electric elevator in Baltimore in 1887. At first, there was a little inducement to develop a practical direct-drive and adequate electrical control system because of the serious difficulty which had existed with the earliest compact steam machine - the necessity for a winding drum with its inherent limitations. The motor's action being rotary, the drum represented the only way of applying electrical power to hoisting. The elevator engineer was right back where he started; with a tall building, his drum would be so wide the machine could not be properly located, nor a satisfactory rope leads accommodated.

The basic form has not changed much in this century except that the drum has disappeared in favor of the traction sheave which has decided advantages. Firstly, there is no reasonable limitation on height. There is, of course, a limitation based on sheave shaft load and compensating ropes are used on high rises. Secondly, a traction machine has a safety feature in that overruns i.e. if the counterweight lands on the buffers, it reduces the traction of the rope on the sheave and the ropes skid thereby preventing the car being pulled up into the headgear. There have been variations of the basic design, but most manufacturers today produce the simplest form of worm gear reduction device with a traction sheave, double thrust bearings and an automatically applied brake on the motor to worm coupling.

These machines vary in size within wide limits - some are 0 cm high and some are 2,5 m high - loads are supported - varying from a few kilograms to many tons.

All geared machines, satisfactory though they may be at low speeds, have limitations on high speeds. To keep gear speeds down, sheaves can be increased in diameter, but the limit is tooth pressure. The industry solved the problem by producing the gearless machine: Aptly named, it consists of a large motor with a traction sheave and brake on the main shaft. The motors are D.C., Ward Leonard controlled with a closed-loop circuit, and handle the loads at speeds from 1 r/m at leveling speed to 200 r/m at some full speeds. It is interesting to note that although there appears to be no electro-mechanical limit to speed, there is a physical limit, based on, of all things, change in barometric pressure affecting passengers with sensitive eardrums. Somewhere around 450 to 520 meters per minute seems to be the comfortable limit.

Mine hoists carrying passengers are of course faster - but the passengers are a select group in top physical shape.

South Africa at the end of the last century was a long way from Europe and America but nevertheless played a part in the historical development of the elevator. In 1862 the Somerset Hospital in Cape Town had a hand-operated installation. Somewhere in the 1880s a steam elevator was installed in Johannesburg in the Castle Breweries - where the new Carlton Hotel now stands. It was in working order until the building was demolished some years ago, and is now in the Transport Museum. In 1882 John Garlick installed a hydraulic elevator, followed soon after by Stuttafords. In 1895 Heynes Matthew of Cape Town installed the first electric elevator in Southern Africa. In 1924 the first gearless machine was installed in Johannesburg and is still in service.

There are side effects of course. The increase in population density in central city areas produced transport problems which apparently will never be adequately solved.

To many people, the elevator consists of a landing and an elevator car. In these areas, therefore, safety has predominated - combined of course with Architectural treatment. Both aspects have undergone changes.

In the early days, hoistways had no protection and elevator speeds were low. Quite obviously this was not enough, and accidents were frequent. The collapsible gate became a standard fitting, and there were many here in South Africa. It is only in the last few years that most of them have disappeared. These gates were fitted first with manual latches - then a gravity type contact was added, and later an electro-mechanical interlock was developed. The same type of gate was introduced in the car. In Europe, there are many elevators without car gates or car doors.

Collapsible gates served their purpose while elevator speeds were reasonable. High speeds required more positive protection and solid doors became mandatory by regulation.

Elevator shafts were of course also open, in many cases, in stair wells. Modern buildings have walls as enclosures - also by regulation. The fire regulations playing an important part in the design. Manually operated doors were satisfactory when attendants controlled the elevator and opened and closed the doors. They also supervised the opening to prevent injury. As the automatic operation was developed, so devices were designed to open and close doors automatically and thereafter police the opening to prevent passengers from being struck by the panels.

Many forms of door operation exist, from pneumatic cylinders to electrical devices of many types. It is important that only the door on which the car is stationary is opened and therefore these devices are located on the car itself - linked to the landing door by cams or skids, which obviously must be kept clear of all entrances bypassed by the car. Modern versions are all electrical motor driven and with a quick reversal. Many are spring closed to limit the closing pressure. Devices to reverse a door meeting an obstruction are also varied. They range from hinged safety shoes operating safety contacts to photocell protection and now the electronic detector, which is a proximity detector and does not need to touch the obstruction before reversing.

All these devices, whilst they do not necessarily make for quicker or more efficient operation, certainly make for increased safety. Quite apart from the actual development of the equipment itself, it is interesting to see the change in Architectural styles which have taken place over the years. From the ornate and elaborate to the simple and austere.

Changes which have taken place in this century in the machine room, have been really significant only in the control apparatus. In this field, a great deal of ingenuity and inventive capacity has been displayed.

Initially, in the changeover from hydraulic to electric, the rope which operated the hydraulic valves was used to operate an electrical contractor - so we had the hand rope operated attendant controlled electric elevator.

This was a clumsy way for an electrical engineer to control a device, and the car switch appeared. A device which operated a contactor by remote control and eliminated the hand rope, but immediately required a power supply cable in the car. It is interesting to see how designers always tend to design to the pattern, and the first final limits on car switch lifts were all rope controlled with stops to operate the limit switch. It was many years before they became cam operated.

Attendant operated elevators prevailed for many years - not because the designers lacked ideas - they lacked incentive, as few people would have dared to operate an automatic elevator.

Inevitably automatic operation finally caught the imagination of investors who owned infrequently used elevators in warehouses, apartments, etc. The first Full Automatic Push Button Elevator appeared. The passenger operated the elevator by pushing buttons: one to call the car, and having entered and closed the doors, one to send the car to the selected floor. These complicated devices actually appear d as early as the 1890s but did not find universal acceptance in Europe until the 1920s. In fact, in many cases, automat lift is still not popular.

This was a taxi service - once occupied the passenger had the exclusive use until the journey was completed. This might be acceptable in a small building but was certainly wasteful, frustrating and undesirable. So a type of bus service was developed - called oil active control. It was possible to register more than one floor at a time, and the elevator would stop in sequence. Included in this development were the refinements of direction. An "up" elevator would not stop for a passenger who wished to go down but would do so on its downward journey. Also, automatic reversal when the highest registered call was answered. In fact, a host of details designed to provide maximum service. There is one significant failure in these ideals: the inability of the industry to persuade the public to press only the button which indicates their intended direction of travel, and not both. Coincidental with the development of automatic elevators for smaller buildings, the larger office blocks still had attendant operated groups. Random service could hardly be called efficient, so the next stage in this field was to interconnect them. First by providing signal information, so each attendant knew the location of the adjacent cars, and then by actual control. In fact, there were two additions to the attendant operated elevator which very important and formed steps in the chain of development.

First, the acceleration and deceleration operations were removed from the attendant's control. Once initiated, the stop was automatic to the next floor. Secondly, the choices of the floor by visual means were eliminated and the attendant registered the call by pushing a button, and the elevator did the rest. In fact, the elevator stopped landing passengers without any action on the part of the attendant. These developments made the coupling groups of elevators possible and group operation with loading and despatch signals appeared.

Group operation with attendants was a very fine arrangement and was very popular until costs became a factor. Attendants in the U.S.A. are said to cost somewhere between 5 t thousand rand per annum each. In a building with 60 elevators, and there are many, there would be 6S or 70 attendants, and the cost something in excess of half a million rand per year, naturally building owners provided the pressure produce interconnected groups of automatic elevators and these appeared under various trade names. Basically the system is designed to split the group to provide maximum coverage in both directions. This is doing automatically and the various alternative program built into the system are selected by the frequency demand itself. 

This is not a suitable occasion on which to discuss the circuits or the available characteristics, but we might at least have a look at the devices which have been developed to provide the means. The position of the car is always of paramount importance. On it is based a multitude of functions. It is necessary to know: the exact position of the car platform in order to keep it level with the landing floor; the direction of travel and when stopped, the intended or registered direction for future travel; all car and landing calls registered, and which is which, as they are treated differently; if there are people in the car, and roughly how many; how long a landing call has remained unanswered; if the landing door is being obstructed; the directional load in the building that is, are most people coming in or going out? Much of this data can be collected if there is apparatus in the car, but this is clumsy and difficult. It is easier to reproduce the conditions on a miniature in the machine room. These selectors ha e a long history and have been used in one form, or another since the 1900s. Some are electrically driven by Selsyn motors or similar - others by a tape or a rope attached to the car and faithfully reproducing the motion of the car on a reduced scale.  Apart from the contact brushed by the crosshead, the selector keeps the car level with the floor. It is also equipped with sophisticated floor advancer panels which, on high-speed installations, literally slows down the machine on inter-floor travel before the elevator has started. In addition, it slows down the elevator some tars or three floors in advance by leapfrogging the floor bars.

The circuitry on the control panels has, naturally advanced with the times, and the constant demand for additional features. A modern controller is equipped with some solid-state blocking rectifiers, timing condensers, voltage transformers, counting and time devices for each and every function. Perhaps the needs would clearer if some of the functions of a group operated automatic installation are described.

Zones are created in the building and the system provides that a car - any of them - is assigned to a zone and will answer the landing calls in that Zone. As soon as one car moves out - another is sent to replace it. Analog computers monitor the traffic in each Zone, find end other cars to help out when peak demands occur.

Each car returns to an empty zone as soon as it has answered its highest or lowest call. There will always be a car at the entrance lobby. When this car leaves the lowest parked zone car will replace it. If two zones momentarily become vacant, they both become an extension of the next lower occupied zone. Landing calls behind a traveling elevator are answered by the nearest parked or up-traveling car in the zone below.

The presence of a travelling car in an occupied zone will answer the calls and prevent the parked car from moving thus avoiding duplication. The analog computers generate an output. the level of which is proportioned to the number of unanswered calls in its zone. A pre-set deduction is made for each elevator present in the zone. If the net result exceeds a set threshold, the zone is classified as high demand and the system does something about it.

The same sort of exercise is performed in the lobby.  High intensity - such as morning peaks results in all the cars being sent down to help out. To achieve these and many other functions, not only are the calls made on the system counted - but the load in the car is weighed by switches beneath the platform.

As it takes less time to leave a car than to enter it - the car calls provide a shorter door open time than landing calls. If the doors are held open too long a nudging operation closes them slowly - a buzzer sounds and indicator lights flick on and off. There is a device that cancels car calls if the car has no load in it, reasoning that such a thing is not possible. A full elevator bypasses all landing calls reasoning that there is no purpose in stopping if there is no room in the car.

There are in fact many other features provided to improve the efficiency of the system, but these quoted are sufficient to illustrate the developments which have occurred this century in the control apparatus.

Today the problems are not operational, but economic.

An elevator can be made to function as desired, but all elevators need space and space is expensive. The space for elevators in the Empire State Building is half the floor area! Means of recovering some of this floor space and converting it to the rentable area have just been developed.

One arrangement in use in the World Trade Centre is a "lobby in the sky" concept. Very large elevators leave the ground floor and travel non-stop to the 44th and 77th floors - one group to each lobby. From these lobbies, local groups depart to serve the building section. In effect, the building is three buildings on top of each other - each with its own elevator system. This permits two elevators to be in one shaft in the plan. One in the lower part of the building and one in the upper part of the building.

They do not of course at any time share the same section of the shaft. Actually there is a machine room between them.

An alternative system is the use of a double-deck arrangement. There are quite a few in use now. Here each car is double-decked - original elsewhere, but common practice on our mines. This doubles the capacity of the lift without increasing the shaft sizes and each car serves two floors at one time. Cost studies indicate that the additional cost of the equipment is more than compensated by the income from the rentable area recovered.

It is an interesting exercise to try and look into the future.

The American Architect Frank Lloyd Wright designed a building that was to be one mile high. and some elevator studies were done for the project. It is conceivable that such an elevator installation would need cars to be despatched at timed intervals, not at random.  It would need an elevator time table.

The Gearless Machine is over seventy years old and difficult to see how it can be improved.

Control devices will tend to the solid-state and modules will be replaceable. This will be necessary because circuit technology will be in advance of the ability of the industry to train its field staff.

In fact, the transfer of knowledge from the design center to the field will be a problem. Things are moving too fast today.

There will be improvements in indoor devices and suitable linear motors will be developed.

Safety devices are pretty safe today, but there is no doubt that many of them will be simplified without loss of efficiency. Preassembly of parts major components and even complete elevators will become standard. It is already well advanced on the continent in the building industry. Complete machine rooms are hoisted into place as standard practice. In fact, the present custom-built elevator can only be made less costly if some degree of standardisation is accepted by our designers.

The elimination of moving parts will tend to reduce stoppages - most of which are caused by the failure of one of the many safety switches forming part of the system. Design engineers’ intent on the complexities of circuitry and increasing the sophistication of each generation have a tendency to forget some of the basic needs of people. For example - for some years. windows were fitted to lift car doors to satisfy those who suffered from claustrophobia. There was nothing to see except the wall of the shaft - but it satisfied a need.

Many people are afraid to ride alone in an elevator.  Not much can be done about this. Security in elevators is now having attention and live microphones and television cameras are being tilted to elevator car to provide prompt assistance if needed and in any event to act as a deterrent to law-breakers.

With better service, and the service provided for today’s tenants is much better users to become more critical and seconds easily become magnified into minutes. People are impatient when cars are waiting for despatch signals and ignore the needs of fellow users.

How to satisfy these human failings is difficult to forecast?

In all the developments this century - South Africa has played a part. The standards set by the industry compare favourably with any part of the world and are superior to most countries. In addition, the Mining Industry has provided a unique field for experiment and experience.

In the de Beers Mine in Kimberley, there is an elevator with the world's longest travel and the world's highest speed! A speed of 650 meters per minute and a travel equivalent to three hundred and twenty floors - six times the travel of the Carlton Centre. It is radio-controlled, automatically operated, and has a lifting capacity of 4 500 kg. The machine weighs 26 tons and supports a total sheave shaft load of 73000 kg, on six 22 mm diameter ropes on round seat grooves. The gearless motor is 320 kW.  It is radio-controlled because it is not yet possible to procure a traveling cable which can support its own weight for the travel.

To conclude, it must be acknowledged that the elevator industry has certainly made a contribution to our modern society.