Abstract: A hydraulic operating apparatus including an actuating cylinder having a piston arranged therein and moved by a fluid under high pressure further includes a control valve having only one metallic seal whether the piston is at its upper or lower positions. The control valve is operative to apply the fluid under high pressure to a pressure receiving surface of the piston on the opposite side of a piston rod to move the piston in a direction in which the piston rod extends from the piston and to discharge the fluid existent on the opposite side of the piston rod from the actuating cylinder to move the piston in a direction opposite the direction in which the piston rod extends from the piston.

Abstract: A speed control system for a hydraulic elevator, in which, actuating a hydraulic pump by driving an induction motor in forward direction, oil is supplied to a hydraulic cylinder for upward travel of an elevator cage, while the hydraulic pump is driven to discharge the oil from the hydraulic cylinder by driving the induction in reverse direction for downward travel of the cage. The induction motor is a single two-speed motor, which is switched to drive the hydraulic pump in one of the two speeds as desired, thus subjecting the elevator cage to two-speed control.

Abstract: A floor level correcting device used in a hydraulic elevator comprises means for electrically detecting the vertical position of the elevator cage with respect to the floor landing and driving means for level correction, provided independent of a main power unit for driving the elevator cage. The detecting means comprises means provided in the elevator shaft and means provided in the elevator cage which detect, in co-operation with each other, the level of the cage with respect to the floor landing of the building in particular whether the cage is stopped in the proper landing position or shifted therefrom, so as to produce an electrical signal in accordance with the detected cage level to transmit the signal to the driving means for level correction.