Abstract: A roped hydraulic elevator has a hydraulic jack whose upper end, preferably the plunger end, is secured to an upper region of the elevator hoistway, and whose lower end is free to move vertically. A first sheave is supported by the lower end of the jack, and at least one overhead sheave is supported in the upper hoistway region. A rope has one end secured to the hoistway near the top of the hoistway. The rope extends downwardly, around the first sheave, upwardly from the first sheave to the overhead sheave, and downwardly from the overhead sheave to the car, where it is secured. Preferably, a counterweight is supported by the lower end of said jack. Also, preferably one or more guide rails and guide shoes are used to guide the movement of the jack lower end and counterweight. The elevator is relatively simple in design, and the roping system produces a 2:1 ratio of car movement to jack movement, which allows the use of a shorter jack or, alternatively, a greater range of car travel.

Abstract: A hydraulic elevator includes a car supported by at least one jack, and a fluid line for venting hydraulic fluid from the jack for lowering the car. An overspeed valve, disposed in the fluid line, comprises a housing having an inlet chamber and an outlet chamber. A piston is mounted on a stem disposed inside of the housing so as to be axially moveable, relative to the stem and housing, between an open position, allowing fluid communication between the inlet chamber and the outlet chamber, and a closed position, in which the piston at least essentially blocks fluid communication between said inlet and outlet chambers. A pressure chamber is formed behind the rearward end of the piston, and a conduit, preferably formed in the piston, allows fluid from the inlet chamber to flow into the pressure chamber. A spring, together with the pressure downstream of the valve, urge the piston towards its open position, whereas fluid in the pressure chamber urge the piston towards its closed position.

Abstract: A twin post, telescoping jack hydraulic elevator system has a pair of dynamic sensors to determine when the jacks are out of synchronization, by determining any relative differences in height between the two intermediate cylinders. The elevator also includes static sensors to determine if one or both intermediate cylinders are more than a predetermined distance away from their normal positions when the car is stopped at each floor. The controller actuates a resynchronization if the distance between the intermediate jacks exceeds a first threshold, and shuts down the elevator if the distance exceeds a second threshold or if resynchronization demands are issued too often. Preferably, the static sensors are positioned to detect the seal housing at the top of the intermediate cylinder, which projects outwardly from the cylinder.