Improvement in Hydraulic Elevators

The objects of my invention are, first, to utilize, for operating freight or passenger elevators, the power derived from the difference in the hydraulic pressure between the high and low service-pipes in city supplies, whereby there is no waste or consumption of water- i.e., the water is taken from the high service-pipes, using the power derived therefrom; it is then discharged by forcing it into the low service-pipes, from which it is available for use; second, to provide a ready and convenient means for efficiently operating the action of the vale; third, by a peculiar construction of the operating parts of the valve or valves, to give to the operator complete control of the car, and insure an easy, uniform motion to the elevator when the water is let on or shut off; fourth, by a peculiar construction of the vale, to obtain a perforated waterport, so the cup-leathers will pass it smoothly.https://digitalcommons.wpi.edu/patents/1014/thumbnail.jp