Detection and Change of Tension Forces Operating on Elevator Hoist Ropes

The Decree on Technical Requirements for Buildings stipulates that all the new residential buildings with entrances to flats at the fifth and higher floors, or attics at the same level, must have an elevator installed. The applicable standards in the Czech Republic so that, for the electric elevators with friction discs that use two or more hoist ropes, the weight of the applied load was evenly distributed over all the cross-sections of the hoist ropes for the given layout of the elevator. Rope tension equalizers used in elevators are usually designed to allow sensing of the acting tensile forces in an uninterrupted cross-section of the hoist cable. They are usually installed on hoist ropes only in the newly-installed elevators and during regular inspections. The paper describes the basic principles of devices currently in use, the so-called rope tensioners, which allow detecting and adjusting primarily different tensile forces in the hoist ropes to the same value. The paper refers to two, already published design variants of portable rope straighteners, which use foil strain gauges or strain gauge sensors to detect the acting tensile forces in the hoist ropes. The constructional solution and the principle of operation of the “hydraulic rope tensioner”, which were created at the VŠB-Technical University of Ostrava, are described in more detail.