| 摘要 |
PURPOSE: To operate an elevator cage safely and lower it without generating shocks by providing a circuit means for opening a check valve between a pump means and a cylinder when a fluid pressure in the former becomes approximately equal to a fluid pressure in the latter and opening the check valve when the cage is required to be lowered. CONSTITUTION: When a cage 12 is stopped at a landing, a truncated conic section 72 of a check valve 36 sits on a peripheral portion 78 of a central bore 42, hydraulic oil 26 is prevented from flowing from a hydraulic cylinder 16 to a tank 24 via a line 54, a valve 18, and a line 28, and the cage 12 is held at the landing. When the cage 12 is required to be lowered, switching to a first circuit 98 by exciting a solenoid valve 38, the first fluid pressure F1 communicates with an opening end 84 of a cylinder 80. When the first fluid pressure F1 pressing a piston 82 becomes larger than the sum of the second fluid pressure F2 and the spring force, the truncated conic section 72 separates from the peripheral portion 78 and the check valve 36 is opened. |
