Figure 8. — In the typical steam elevator 

 machine t\vo vertical cylinders were situated 

 either above or below the crankshaft, and a 

 small pulley was keyed to the crankshaft. In 

 a light-duty machine, the power was trans- 

 mitted by flatbelt from the small pulley to 

 a larger one mounted directly on the drum. 

 In heavy-duty machines, spur gearing was 

 interposed between the large secondary pulley 

 and the winding drum. (Photo courtesy of 

 Otis Elevator Company.) 



THE STEAM ELEVATOR 



The progression from an elevator machine powered 

 by the line shafting of a mill to one in which the 

 power source was independent would appear a simple 

 and direct one. Nevertheless, it was about 40 years 

 after the introduction of the powered elevator before 

 it became common to couple elevator machines di- 

 rectly to separate engines. The multiple belt and 

 pulley transmission system was at first retained, but it 

 soon became evident that a more satisfactory service 

 resulted from stopping and reversing the engine itself, 

 using a single fixed belt to connect the engine and 

 winding mechanism. Interestingly, the same pattern 

 was followed 40 years later when the first attempts 

 were made to apply the electric motor to elevator 

 drive. 



Figure g. — Several manufacturers built steam 

 machines in which a gear on the drum shaft 

 meshed directly with a worm on the crankshaft. 

 This arrangement eliminated the belt, and, 

 since the drum could not drive the engine 

 through the worm gearing, no brake was neces- 

 sary for holding the load. (Courtesy of Otis 

 Elevator Company.) 



By 1870 the steam elevator machine had attained 

 its ultimate form, which, except for a number of 

 minor refinements, was to remain unchanged until the 

 type became completely obsolete toward the end of 

 the century. 



By the last quarter of the century, a continuous 

 series of improvements in the valving, control systems, 

 and safety features of the steam machine had made 

 possible an elevator able to compete with the subse- 

 quently appearing hydraulic systems for freight and 

 low-rise passenger service insofar as smoothness, 

 control, and lifting power were concerned. However, 

 steam machinery began to fail in this competition as 

 the increasing height of buildings rapidly extended 

 the demands of speed and length of rise. 



The limitation in rise constituted the most serious 

 shortcoming of the steam elevator (figs. 8-10), an in- 

 herent defect that did not exist in the various hydraulic 

 systeins. 



Since the only practical way in which the power of a 

 steam engine could be applied to the haulage of 

 elevator cables was through a rotational system, the 



PAPER 19: ELEVATOR SYSTEMS OF THE EIFFEL TOWER 

 552119—61 2 



