Epilogue
In 1900, after the customary 11-year period, Paris again prepared for an international exposition, about 5 years too early to take advantage of the great progress made by the electric elevator. When the Roux machines, the weakest element in the Eiffel Tower system, were replaced at this time, it was by other hydraulics. Built by the well known French engineering organization of Fives-Lilles, the new machines were the ultimate in power, control, and general excellence of operation. As in the Otis system, the cars ran all the way to the second platform.
The Fives-Lilles equipment reflected the advance of European elevator engineering in this short time. The machines were rope-geared and incorporated the elegant feature of self-leveling cabins which compensated for the varying track inclination. For the 1900 fair, the Otis elevator in the south pier was also removed and a wide stairway to the first platform built in its place. In 1912, 25 years after Backmann’s startling proposal to use electricity for his system, the remaining Otis elevator was replaced by a small electric one. This innovation was reluctantly introduced solely for the purpose of accommodating visitors in the winter when the hydraulic systems were shut down due to freezing weather. The electric elevator had a short life, being removed in 1922 when the number of winter visitors increased far beyond its capacity. However, the two hydraulic systems were modified to operate in freezing temperatures—presumably by the simple expedient of adding an antifreezing chemical to the water—and operation was placed on a year-round basis.
Today the two Fives-Lilles hydraulic systems remain in full use; and visitors reach the Tower’s summit by Edoux’s elevator ([fig. 41]), which is all that remains of the original installation.
Balance of the Three Elevator Systems
The Otis System
| Negative effect | |||||
| Weight of cabin: 23,900 lb. × sin 78°9′ (incline of upper run) | 23,390 | lb. | |||
| Live load: 40 persons @150 lb. = 6,000 × sin 78°9′ | 5,872 | ||||
| ——— | — 29,262 | lb. | |||
| Positive effect | |||||
| Counterweight: 55,000 × sin 54°35′ (incline of lower run) ——————————————— 3 (rope gear ratio) | 14,940 | lb. | |||
| Weight of piston and chariot: 33,060 × sin 54°35′ ——————— 12 (ratio) | 2,245 | ||||
| Power: 156 p.s.i. × 1,134 sq. in. (piston area) —————————————— 12 (ratio) | 14,742 | 31,927 lb. | |||
| Excess to overcome friction | 2,665 lb. |
The Roux, Combaluzier and Lepape System