Page:Federal Reporter, 1st Series, Volume 4.djvu/462

 eeS FBDEBAL KEPOBTBB. �both oylinders as required. By this means the ordinary work of the elevator can be accomplished by one of the cylinders, and when an extraordinary pressure is required both cylindera can be employed, thus providing an elevator that will anawer in any place and do its work -with great economy of water." The claims of this patent are two, as follows: "First, the upright cylinders, A A, with their piston, C C, each of said pistons being provided with an upright and rack bar, d, in combination with the shaft, I, with its epur-wheels, j' j and Z, shaft, l, with its pinion, m, and driving puUy, N, whereby I am enabled to employ the pressure in either one or both cylinders for hoisting purposes, substantially as and for the purpose above descïibed; second, the upright rack bars, d, provided with the rib in combination with the guide spools, h, substantially as and for the purpose above described." �The answer of the defendant admits that he bas made and sold hydràulic elevators construeted according to the descrip- tion in said patent No. 172,896. According to the testimony of defendant's expert, Mr. Eliot, patent No. 172,896 describes an arrangement of two working cylinders provided with suit- able pistons, one of the cylinders and pistons being placed inside of the other in such a manner as to economize room, and at the same time allow both of the pistons to be com- bined with a cross-head, which carries sheaves over which the lifting ropes of the elevator work; the combination and arrangement being such that one of the pistons, with its cor- responding cylinder, can be brought into immediate action to assist the lifting force of the other at the pleasure of the operator or attendant of the elevator. The same expert statea that the peculiar means by which such a resuit is accom- plished consists in making the main working piston in the form of a cylinder, and connecting its upper end immedi- ately with the cross-head that carries the sheaves, and also in Connecting with the said cross-head a piston which worka in an interior cylinder placed coneentric with the outer work- ing piston, and connecting with them a valve in such a man- ner that when the water pressure is brought to bear upon the ����