Abstract: In the energy conservation type hydraulic elevator, a load carrying elevator and a balancing elevator are each provided on a respective hydraulic cylinder. The hydraulic cylinders are connected to one another by a fluid circuit. The balancing elevator is weighted so as to minimize the power input required of a hydraulic pump in the fluid circuit. In the speed control method of a hydraulic elevator, a negative pressure is first produced in a fluid path connecting a hydraulic pump and a control valve. Descent of the elevator is then permitted to start by opening a control valve, allowing hydraulic fluid to flow from a cylinder, by way of a hydraulic pump, to an oil tank. The hydraulic pump and a motor rotate with the hydraulic fluid, and the motor is rotated at a synchronous number of revolutions by switching on an inverter power source when the number of revolutions has reached the synchronous number of revolutions of the motor.

Abstract: In the energy conservation type hydraulic elevator, a load carrying elevator and a balancing elevator are each provided on a respective hydraulic cylinder. The hydraulic cylinders are connected to one another by a fluid circuit. The balancing elevator is weighted so as to minimize the power input required of a hydraulic pump in the fluid circuit. In the speed control method of a hydraulic elevator, a negative pressure is first produced in a fluid path connecting a hydraulic pump and a control valve so that oil is drawn into the fluid flow path from an oil tank by way of a nonreturn valve. Descent of the elevator is then permitted to start by opening a control valve, allowing hydraulic fluid to flow from a cylinder, by way of a hydraulic pump, to an oil tank.