Hydraulic Elevator Systems - Page 50

The mechanically synchronized Gemini jack provides smooth, balanced elevator cab movement; easy, cost-effective maintenance; and reduced elevator downtime. It requires less hoistway space than other telescopic jacks. Its independently guided jacks result in less wear on seals. Because the system does not rely on sensitive, internal hydraulic valves, it avoids malfunction due to seal leakage, uneven oil cycling, and other hard-to-observe problems.

Chain synchronization used by the Gemini system keeps all jack sections in correct position at all times. Because the jack operations are equalized, elevator shutdowns due to imbalance are eliminated. A broken chain valve provides extra safety, and a shut-off valve for each jack is also provided.