Bucher Hydraulics Ag

Hugo Birbaumer

Richard Von Holzen

A hydraulic elevator with a pressure accumulator includes a pump fir conveying hydraulic oil between the pressure accumulator and a hydraulic drive, such that the direction of rotation of the pump can be changed. An electrically controlled cylinder line stop valve is installed on one side of the pump, and an electrically controlled accumulator line stop valve is installed on the other side of the pump. Both valves are ON-OFF valves. To prevent sudden disruptive pressure changes when the valves are opened before the start of travel of the car, the pressure in the section of the line between the pump and the cylinder line stop valve and in the section of the line between the pump and the accumulator line stop valve can be varied such that, when the car is at a standstill, the pressure differences are largely eliminated before the valves are opened.

Hydraulic elevator with valve for preventing discharge of pressure accumulator and method of controlling same

Apparatus for determining the position of an elevator car in an elevator shaft includes a resistance wire installed vertically in the elevator shaft, the wire having a first end supplied with an operating voltage and a second end supplied with a reference voltage; a voltage tap installed on the elevator car, the voltage tap having a contact which rides on the resistance wire between the ends; and a position sensing unit connected to the voltage tap by a measuring line.

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Neuheim, Switzerland

Hugo Birbaumer