Figure 1 1 . — Armstrong's hydraulic crane. The main cylinder was inclined, 

 permitting gravity to assist in overhauling the hook. The small cylinder ro- 

 tated the crane. (From John H. Jallings, Elevators, Chicago, 1916, p. 82.) 



of a 3-to-l tackle, with the effort and load elenients 

 reversed. Simple valves controlled admission and 

 exhaust of the water. (See fig. 11.) 



The success of this system initiated a sizable industr 

 in England, and the hydraulic crane, with man 

 modifications, was in common use ther e for man 

 years. Such cranes were introduced in the United 

 States in about 1867 but never became popular; 

 they did, however, have a profound influence on the 

 elevator art, forming the basis of the third generic 

 type to achieve widespread use in this country. 



The ease of translation from the Armstrong crane 

 to an elevator system could hardly have been more 

 evident, only two alterations of consequence being- 

 necessary in the passage. A guided platform or car 

 was substituted for the hook; and the control valves 

 were connected to a stationary endless rope that was 

 accessible to an operator on the car. 



The rope-geared hydraulic system (fig. 1 3) appeared 

 in mature form in about 1 876. However, before it had 

 become the "standard elevator" through a process 

 of refinement, another system was introduced which 

 merits notice if for no other reason than that its 

 popularity for some years seems remarkable in view 



of its preposterously unsafe design. Patented by 

 Cyrus W. Baldwin of Boston in January 1870, this 

 system was termed the Hydro-Atmospheric Elevator, 

 but more commonly known as the water-balance ele- 

 vator (fig. 12). It employed water not under pressure 

 but siinply as mass under the influence of gravity. The 

 elevator car's supporting cables ran over sheaves at the 

 top of the shaft to a large iron bucket, which traveled 

 in a closed tube or well adjacent to and the saine length 

 as the shaft. To raise the car, the operator caused 

 a valve to open, filling the bucket with water from 

 a roof tank. When the weight of water was sufficient 

 to overbalance the loaded car, the bucket descended, 

 raising the car. On its ascent the car was stopped at 

 intermediate floors by a strong brake that gripped the 

 guides. Upon reaching the top, the operator was 

 able to open a valve in the bucket, now at the bottom 

 of its travel, and discharge its contents into a base- 

 ment tank, to be pumped back to the roof. No 

 longer counterbalanced, the car could descend, its 

 speed controlled solely by the brake. 



The great popularity of this novel system apparently 

 was due to its smooth operation, high speed, simplicity, 

 and economy of operation. Managed by a skillful 



PAPER 19: ELEVATOR SYSTEMS OF THE EIFFEL TOWER 



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