This page was created by Ray Li.
Types of Elevators
In 1878, Cyrus Baldwin invented the vertical cylinder hydraulic elevator. It was first installed in the Boreel Building and became the standard for years to come.11 Two variations of the hydraulic system emerged. The geared hydraulic elevator used “steam-driven pumps to force water to activate pistons positioned in cylinders vertically in the shaft.”12 The car was attached to the piston through a pulley system and the assembly was located to the side of the car. The pulley “multiplied the stroke of the piston”, allowing the car to travel twice the distance that the piston moved.13 These were used in buildings with heights of several hundred feet and could travel as fast as 200 feet a minute. The second type, the direct plunger, used a car that “sat directly on a piston in a vertical cylinder and was activated when an influx of water drove the car up; water was released so the car could descend.”12 Direct plunger systems were rarely used in buildings taller than ten stories as the cylinder had to “extend into the ground to a depth equal to the height that the elevator rose.”12 The water used by the pistons was stored in large tanks in both variations. The process involved the “use of the water over and over again”, reducing the cost for operating elevators.[4]
The next breakthrough in elevator design occurred in 1890 with the advent of the electric traction elevator. In this system, a set of steel driving cables was used to move the elevator car. One end of the driving cables was attached to the car while the other end was attached to a counterweight to offset the weight of the load. The steel cables were passed over a sheave – wheel with grooves – that was then connected to a gearbox and electric motor. The motor controlled the direction that the wheel turned, either raising the car or lowering the car.[5] The main advantage of this new system was that it “consumed power only in proportion to the load” and since the power was obtained from central power stations, “there was no expense when the motor was idle.”[6] The hydraulic system, on the other hand, required the same amount of power regardless of the load. This was due to the fact that “the water [was] pumped at a fixed pressure and the same volume of water [was] used for a trip irrespective of the load carried by the car.”15 Hydraulic elevators also required the addition of a pumping station within the building which had “standby losses even when the elevator car was not in operation.”15 Geared traction elevators were considerably faster than their hydraulic counterparts, traveling at speeds up to 500 feet a minute.[7]
[1] OTIS BROS, &. C. O. (1883). ABOUT ELEVATORS.--HYDRAULIC VERSUS STEAM POWER. The American Architect and Building News (1876-1908), 14(393), 1.
[2] PASSENGER ELEVATORS.1--I. (1904). The American Architect and Building News (1876-1908), 86(1507), 51.
[3] Ross, W. “THE RISE-BUT RARELY THE FALL-OF the elevator”. The Washington Post (Pre-1997 Fulltext), Mar 21, 1995.
[4] OTIS BROS, &. C. O. (1883). ABOUT ELEVATORS.--HYDRAULIC VERSUS STEAM POWER. The American Architect and Building News (1876-1908), 14(393), 1.
[5] Passenger elevators--IV. (1904). The American Architect and Building News (1876-1908), 86(1511), 83.
[6] H, D. JAMES. "VERTICAL TRANSPORTATION." The American Architect and the Architectural Review (1921-1924) 125, no. 2445 (May 07, 1924): 451.
