Historical review

A fascinating book published by the Otis Elevator Company, Going Up, in 1983 traces the history in detail with wonderful drawings of early hoists and lifts.1 That history is described with illustrations in Stairs, Steps and Ramps. Sufficient to record here that the Romans used hoists at the Colosseum for lifting the animals and gladiators into the amphitheatre, and also to lift heavy building materials for their temples etc. These hoists were in the form of a pulley wheel and rope wound round a geared capstan (Figure 11.1a).

The Industrial Revolution introduced water and steam power to power hoists; the most primitive form reserved for mine shafts was termed a 'man engine'. This comprised a single pole of connected timbers with platforms at regular intervals (Figure 11.1b). The up and down action was operated by a steam piston engine with the miners having to adroitly jump on and off the fixed platforms at the side of the shaft. Conventional elevators that used passenger cages and guide cables were water powered in those days. Such patterns were in common use until the 1870s and relied upon hydraulic rams to raise and lower the platform, not unlike 'Oildraulic' powered machinery today.

The revolutionary development of rack and pinion safety locks coupled with steam-powered machinery entirely changed lift engineering with the following dates as marker points in the new technology.

1853 Elisher Graves Otis demonstrated the safety lift by cutting suspension cable at the New York Crystal Palace Exhibition while a passenger on his own machine.

Figure 11.1a Medieval cathedral hoists (by kind permission of Otis Elevator plc)

1857 First Otis passenger lifts fitted in a

Broadway store, New York. 1859 First Otis steam-powered lift. 1865 First Edoux hydraulic lift for the building trade. 1880 First Siemens electric lift.

1889 Otis electric lifts for the ascent to the second platform at the Eiffel Tower.2

1890 Paris International Exhibition. Moving pavements and escalators demonstrated for the first time. Escalators were patented by Otis and the word registered.

The movement pattern achieved by lifts totally changed the way tall buildings could be contrived. Dreams like the 'mile high' skyscraper of Frank Lloyd Wright

Otis Platform Lift
Figure 11.1b 'Man Engine' as used in Cornish tin mines (by kind permission of Otis Elevator plc)

have still to be built but the high rise architecture that distinguishes the twentieth and twenty-first centuries from previous history would never have occurred without the pioneering work of lift engineers in the nineteenth century (Figure 11.1c). The escalator and travelator first demonstrated at the Paris Exhibition in 1900

Figure 11.1c Lift cage in the Bradbury Building, Los Angeles, 1893, Architect: George M. Wyman (see also Figure 3 23)

have in turn transformed the handling of crowds in vast multi-storey spaces.

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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