Figure 31. — The French Ghard pumps that suppHed the Otis and 

 Roux systems. (From La Nature, Oct. 5, i88g, vol. 17, p. 292.) 



The direct plunger elevator was the only type in 

 which European practice was in advance of American 

 practice at this time. Not until the beginning of the 

 20th century, when hydraulic systems were forced 

 into competition with electrical systems, was the 

 direct plunger elevator improved in America to the 

 extent of being practically capable of high rises and 

 speeds. Another reason for its early disfavor in the 

 United States was the necessity for drilling an expen- 

 sive plunger well equal in length to the rise." 



As mentioned, the most serious problem confronting 

 Edoux was the extremely high rise of 525 feet. The 

 Trocadero elevator, then the highest plunger machine 

 in the world, traveled only aljout 230 feet. A second- 



ly Improved oil-well drilling techniques were influential in 

 the intense but short burst of popularity enjoyed by direct 

 plunger systems in the United States between 1899 and 1910. 

 In New York, many such systems of 200-foot rise, and one of 

 380 feet, were installed. 



ary difficulty was the esthetic undesirability of per- 

 mitting a plunger cylinder to project downward 

 a distance equal to such a rise, which would have 

 carried it directly into the center of the open area be- 

 neath the first platform (fig. 6). Both problems were 

 met by an ingenious modification of the basic system. 

 The run was divided into two equal sections, each of 

 262 feet, and two cars were used. One operated from 

 the bottom of the run at the second platform level 

 to an intermediate platform half-way up, while the 

 other operated from this point to the observation 

 platform near the top of the Tower. The two sections 

 were of course parallel, but offset. A central guide, 

 on the Tower's center-line, running the entire 525 

 feet served both cars, with shorter guides on either 

 side — one for the upper and one for the lower run. 

 Thus, each car traveled only half the total distance. 

 The two cars were connected, as in the Backmann 

 system, by steel cables running over sheaves at the 



32 



BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



