track upon which ran rollers attached to revolving 

 frames underneath the cars. When the frames were 

 made to revolve, the rollers, running around the track, 

 would raise or lower one car, the other traveling in 

 the opposite direction (fig. 23). 



In the plan as first presented, a ground-based steam 

 engine drove the frames and rollers through an end- 

 less fly rope — traveling at high speed presumably to 

 permit it to be of small diameter and still transmit a 

 reasonable amount of power — which engaged pulleys 

 on the cars. The design was remarkably similar to 

 that of the Miller Patent Screw Hoisting Machine, 

 which had had a brief life in the United States around 

 1865. The Miller system (see p. 19) used a flat belt 

 rather than a rope (fig. 20). This plan was quickly 

 rejected, probably because of anticipated difficulties 

 with the rope transmission.^ 



Backmann's second proposal, actually approved by 

 the Commission, incorporated the only — although 

 highly significant — innovation evident in his designs. 

 For the rope transmission, electric motors were sub- 

 stituted, one in each car to drive the roller frame 

 directly. With this modification, the plan does not 

 seem quite as unreasonable, and would probably have 

 worked. However, it would certainly have lacked the 

 necessary durability and would have been extremely 

 expensive. The Commission discarded the whole 

 scheme about the middle of 1888, giving two reasons 

 for its action: (1) the novelty of the system and the 

 attendant possibility of stoppages which might seri- 

 ously interrupt the "exploitation of the Tower," and 

 (2) fear that the rollers running around the tracks 

 would cause excessive noise and vibration. Both 

 reasons seem quite incredible when the Backmann 

 system is compared to one of those actually used — 

 the Roux, described below — which obviously must 

 have been subject to identical failings, and on a far 

 greater scale. More likely there existed an unspoken 

 distrust of electric propulsion. 



That the Backmann system should have been given 

 serious consideration at all reflects the uncertainty 

 surrounding the entire matter of providing elevator 

 service of such unusual nature. Had the Eiffel Tower 

 been erected only 15 years later, the situation would 

 have been simply one of selection. As it was, Eiffel 



9 Mechanical transmission of power by wire rope was a well 

 developed practice at this time, involving in many instances 

 high powers and distances up to a mile. To attempt this 

 system in the Eiffel Tower, crowded with structural work, 

 machinery and people, was another matter. 



and the commissioners were governed not by what 

 they wanted but largely by what was available. 



THE OTIS SYSTEM 



The curvature of the Tower's legs imposed a prob- 

 lem unique in elevator design, and it caused great 

 annoyance to Eiffel, the fair's Commission, and all 

 others concerned. Since a vertical shaftway any- 

 where within the open area beneath the first platform 

 was esthetically unthinkable, the elevators could be 

 placed only in the inclined legs. The problem of 

 reaching the first platform was not serious. The 

 legs were wide enough and their curvature so slight 

 in this lower portion as to permit them to contain 

 a straight run of track, and the service could have been 

 designed along the lines of an ordinary inclined rail- 

 way. It was estimated that the great majority of 

 visitors would go only to this level, attracted by the 

 several international restaurants, bars and other 

 features located there. Two elevators to operate 

 only that far were contracted for with no difficulty — 

 one to be placed in the east leg and one in the west. 



To transport people to the second platform was an 

 altogether different problem. Since there was to be 

 a single run from the ground, it would have been 

 necessary to form the elevator guides either with 

 a constant curvature, approximating that of the legs, 

 or with a series of straight chords connected lay short 

 segmental curves of small radius. Eiffel planned 

 initially to use the first method, but the second was 

 adopted ultimately, probably as being the simpler 

 because only two straight lengths of run were found 

 to be necessary. 



Bids were invited for two elevators on this basis — 

 one each for the north and south legs. Here the un- 

 precedented character of the matter became evident — 

 there was not a firm in France willing to undertake 

 the work. The American Elevator Company, the 

 European branch of Otis Brothers & Company, did 

 submit a proposal through its Paris office, Otis 

 Ascenseur Cie., but the Commission was compelled to 

 reject it because a clause in the fair's charter pro- 

 hibited the use of any foreign material in the con- 

 struction of the Tower. Furthermore, there was 

 a strong prejudice against foreign contractors, which, 

 because of the general background of disfavor sur- 

 rounding the project during its early stages, was an 

 element worth serious consideration by the Commis- 

 sion. The bidding time was extended, and many 

 attempts were made to attract a native design but 

 none was forthcoming. 



PAPER 19: ELEVATOR SYSTEMS OF THE EIFFEL TOWER 



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