Like the sap rising in a forest is the morning flow of Manhattanites to work, as packed elevators in tall buildings whisk them upward by thousands to disperse on higher and higher floors. By the time this life has drained out of the office buildings at 5 p.m. and apartment houses and hotels are full for the night, Manhattan elevators have carried 13,000,000 passengers 95,000 miles. In the business of furnishing vertical transportation to New York and other cities, famed Otis Elevator Co. held an unworried near-monopoly from about 1900 to 1926, controlled as much as 75% of elevator installation in the U. S. Then Westinghouse Electric's new elevator division made Otis feel the pinch of competition, now handles about 20% of the business. In Westinghouse engineering Otis met a worthy rival, perhaps for the first time.
All elevator engineering is based on the simple hoist. Suspended by cables (still "ropes" to elevator men) and balanced by a counterweight, the car is drawn upward on its rails by a motor-driven drum ("sheave") at the top of the shaft. The development of this mechanism from the old geared, hand-operated elevator to the modern skyscraper type was chiefly a matter of making the necessary high speeds comfortable and safe. Pioneering Otis engineers experimenting on Otis employes found that a speed of 1,200 ft. per minute was fast enough, that the rate of acceleration upward of an elevator cannot be greater than 14 ft. per sec. without causing passengers' knees to buckle as gravity's pull abruptly increases their weight.* To slow down and stop high speed elevators Otis perfected its "signal control" system, by which contacts made at every floor with the braking mechanism become effective only when a button has been pushed for a certain floor. Of this type are the Otis elevators (capable of 1,200 ft. per min.) in the Empire State and Chrysler Buildings.
One of the first big Westinghouse coups was the installation of 36 top-speed (1,400 ft. per min.) elevators in Radio City's 69-story Rockefeller Tower. These smooth performers differ from Otis elevators in the use of photo-electric cells instead of the usual electrical contacts for braking and for leveling off at each floor. In en- gineering innovations Westinghouse has kept in stride with Otis by matching Otis' double-decker elevators in Manhattan's Cities Service Building with a system for running two elevators in the same shaft. But Otis' great advantage lies in its maintenance operations, which during Depression reputedly accounted for two-thirds of its total business.
Most likely field for new elevator business in the near future is that of apartment houses and housing projects. What in view of this appeared to be an extremely astute transaction, was announced by Westinghouse last week: the acquisition of old, privately owned A. B. See Elevator Co., third largest in the land and a specialist in medium-height elevator jobs.