Gas-Spring Rope Tensioning for Counterweight-Free Elevators

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Solution Overview

Problem

Existing elevators without counterweights face challenges in maintaining a consistent and stable tension force on the cable pull due to operational changes and disturbances, leading to potential instability and reduced lifting capacity.

Innovation Solution

The use of clamping devices, specifically designed with gas springs, to generate a resultant compressive force on the cable pull, ensuring uniform tensioning even during expansions, shortenings, or temporary deviations, with a compact design that includes adjustable gas springs mounted at specific angles and orientations to maintain stability and minimize space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If hydraulic devices or lever mechanisms are used to control the deflecting pulley force, then the tension force can be controlled depending on the load, but the device complexity increases and the design becomes less compact

Engineering Contradiction:
Improvetension force controlVSAvoidmechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses gas springs (pneumatic elements) to provide the tensioning force on the cable pull. The gas springs are arranged in pairs at specific angles to generate a resultant compressive force that maintains uniform tension. This pneumatic approach replaces complex hydraulic devices or lever mechanisms while achieving the desired tension control through the elastic properties of the gas springs.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Stability of the object's composition

If multiple tensioning devices are used to achieve uniform tensioning, then the cable pull stability improves, but the space requirements and device complexity increase

Engineering Contradiction:
Improvecable pull stabilityVSAvoidspace requirements
Core Design Contradiction:
Stability of the object's compositionVSVolume of stationary object

Solution Approach 1:

The patent combines multiple gas springs into a single tensioning device assembly that acts on the cable pull. The gas springs are arranged in pairs at the same angle to the cable axis, with their forces merging to create a resultant compressive force. This merging approach achieves stable uniform tensioning while maintaining a compact design that minimizes space requirements in the elevator shaft.

Inventive Principle:
Principle #5Merging (Combining)

3Stability of the object's composition

If the tensioning device is mounted in the lower shaft area next to the drive pulley, then the cable pull stability improves and lifting height increases, but the arrangement complexity increases

Engineering Contradiction:
Improvecable pull stabilityVSAvoidarrangement complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent positions the tensioning device with its deflection pulley in the lower shaft area next to the rotary motor and drive pulley, with all three having parallel axes of rotation. This spatial arrangement in three dimensions allows the cable to be guided smoothly from the drive pulley through the deflection pulley to the elevator car, maintaining cable stability while maximizing the vertical lifting height. The parallel axis configuration simplifies the mechanical arrangement compared to alternative configurations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution achieves an extremely uniform and adaptable tensioning of the cable pull, ensuring stable operation and maximizing the lifting height by minimizing space, while maintaining secure cable guidance and detecting potential cable issues for safe operation.

Implementation Method 1

the clamping means are in particular designed as gas springs

Methodology Applied
Scientific EffectGas spring: Spring

Implementation Method 2

generate a resultant compressive force on the cable pull in the clamping direction

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4656574A1Liftwithout counterweight comprising a cable tension device with gas springs
Publication Date: 2025.12.03 EMCH AUFZUGE
  • EP4656574A1 patent drawingFigure 1~2
  • EP4656574A1 patent drawingFigure 3~4
  • EP4656574A1 patent drawing

AI summary

An elevator, in particular a passenger and/or goods elevator, without a counterweight, comprises an elevator car (11) in a shaft and a rope (25) for raising and lowering it. The rope (25) can be driven by a motor via a drive pulley (18) arranged above or below in the shaft (14), is guided around at least one deflection pulley (23) opposite it above or below in the shaft, and is operatively connected to the elevator car (11) above and below. The at least one deflection pulley (23) is held displaceably in a tensioning device (20) by tensioning means in the axial direction (A) of the rope (25) such that the rope (25) is always under tension with a defined force during operation.The clamping device (20) is designed and arranged with several clamping means such that they generate a resultant compressive force on the cable pull (25) in the clamping direction (F), wherein the clamping means are in particular designed as gas springs.