| 摘要 |
PURPOSE: To prevent the excessively accelerated downward movement of an elevator car by balancing fluid pressures in both sides of a check valve means and selectively opening a bypass valve before the start of lowering so as to maintain the closed state of the check valve individually to be biased. CONSTITUTION: A hydraulic valve system for controlling the flowing of hydraulic fluids from a cylinder 22 to a storage tank 24 during the lowering of an elevator 20 is provided with an adjust valve adjustable for controlling hydraulic fluids to the cylinder 22 or therefrom, and a bias check valve 4 placed between the cylinder 22 and the adjust valve and always closed. The system is further provided with a fluid driving means for selectively opening the check valve 4, a bypass valve means operated to balance fluid pressures in both sides of the check valve 4 when the valve is open, and a means for connecting the bypass valve with the fluid driving means for delivering the driving means to the fluid driving means when the bypass valve is open. |
