This content was created by Ray Li.
Gearless Traction Elevator
1 2017-12-19T20:08:13-08:00 Ray Li d76adcdbc48db5fec180c24315aed43f8b9d5f75 14634 1 plain 2017-12-19T20:08:13-08:00 Ray Li d76adcdbc48db5fec180c24315aed43f8b9d5f75This page is referenced by:
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2017-12-19T20:24:00-08:00
Woolworth Building Elevators
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By Ray Li
plain
2017-12-19T20:24:00-08:00
The gearless traction elevator was introduced by Otis Brothers & Co. in 1904.[1] This new system was identical to the geared traction elevator except for one small difference. Improvements to electric motor designs had allowed for the elimination of the gearbox. The new gearless design resulted in better power efficiency and slightly higher speeds.17
This new design was used for the elevators in the Woolworth Building. It was not the first skyscraper to implement the gearless traction system. Otis Brothers & Co. had installed similar elevators in the Singer Building (1908) and the Metropolitan Life Insurance Company Tower (1909).19 However, it was the first time that the elevator had been implemented on such a large scale. As a result, Otis Brothers and Co. had to develop advanced safety features for the Woolworth Building elevators.
When the Woolworth Building opened in 1913, twenty nine Otis elevators served the skyscraper. Twenty seven of these elevators were open to the public. The other two consisted of a private elevator for the Irving National Bank and an ashe lift that ran from the sub-basement to the sidewalk. Of the twenty seven public elevators, seven of the lifts served the tower. These elevators were designed to operate at 700 feet per minute, the fastest passenger elevators in the world at the time. The other twenty elevators served the main building. These elevators ran at 600 feet per minute.[2]
All of the Woolworth Building elevators were equipped with air cushions that were designed to bring the cars “gradually to rest at the bottom of the hatchways in case of a drop even from the top of the shaft.”21 A metallic envelope was installed at the bottom of the shafts to create an “air-tight tube closed at the bottom and the sides.”21 As the elevator car descends, the “progressively compressed air exerts a cushioning effect.”21 As a way to demonstrate the effectiveness of the system, F.T. Ellithorpe, the inventor of the mechanism, dropped 676 feet in one of the Woolworth elevators.[3]
A unique system was also designed to control the elevators. All of the elevators in the building were managed by a dispatcher from a central station located on the main floor balcony. A position indicator lamp board showed the location of each elevator car in the building. Passengers would indicate which direction they wanted to travel by pushing an “up” or “down” button. The operator inside a car would be given a timely signal to stop.21 If the car was unable to stop due to insufficient room or any other reason, the dispatcher would transfer the signal on to the next available car. A telephone was also installed in each elevator car so the dispatcher and operators could maintain full communication at all times.[4]
Human error was also an issue at the time. Eighty five percent of public elevator accidents were related to the operation of doors. Careless elevator operators would sometimes leave the car doors unlocked or start the car while passengers were still attempting to leave or board the elevator. Otis Brothers & Co. resolved this problem by installing Norton Elevator Door Closers in all the cars. With this device, the operator manually opened the door by pressing a button. When the button was released, the door would close automatically and lock. Pressing the button would also break the controlling circuit for the elevator, preventing all motion of the car until the door was closed.22
