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Show High-Speed Elevator Essential to Skyscraper. Sky-scraper. In the last analysis it has boon only tho high-speed elevator that has mado a practical possibility of tho lower building, and succcssivo efforts havo culminated in elevators which travel tho 546 feet of tho Singer Building tower and to the forty-fourth storv in tho tower of tho Metropolitan Lifo Building. Such a journey m the. elova-tors elova-tors used but a few 3'cars ago would have required from ten lo fifteen minutes, min-utes, which of course would havo rendered ren-dered the upper lloors of such a tower unavailable for rental, but today even when the speed of an elevator is limited by Yho building regulations of GOO feet per minuto, it is possible to socuro safe and speedy service. Indeed, many engineers en-gineers think that this restriction is a most wholesomo as well as liberal provision, pro-vision, and it is so found in actual practice, for it is not the time spent by the car in travol that counts, but that required for tho ingress and egress of passengers, amounting often to 75 per cent of the time roquircd for a trip. Thorcforo small cars running with modorato velocity aro usually more advantageous than largo car's of groatcr fjpcod, while as a result of experience it is stated that ono elevator eleva-tor is needed for cvory 25,000 feet of rental lloor space. Now for tho requirements re-quirements of tho very high building two types of. olevator have been evolved, evol-ved, both ofi which in actual uso havo boon found- satisfactory. These aro tho plunger olevator, in which hydraulic hydrau-lic pressure acts .directly on a long plungor working in a cylindor and carrying tho car at its extremity, and tho cablo drivo; elevator, which is based on the direct 'traction principle and is operated by a)n electric motor. From "Tall Buildings and Their Problems," by Herbert T Wado, in tho American Reviow of Reyiews. |