Elevator Traction Slack Detection with Triggering Arm Switching

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing elevator systems face challenges in detecting slack conditions in traction members due to the need for complex and costly detector elements that require additional space and are slow to react to initial slack, potentially leading to unsafe operating conditions.

Innovation Solution

A slack detection unit comprising a support bracket, triggering arm, and switching device mounted near the machine pulley, which detects slack conditions through the deflection of the triggering arm to actuate the switching device without direct interaction with the traction medium, allowing rapid detection of minimal slack.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a detector element is disposed at both ends of the hoisting ropes, then the slack condition can be detected, but it requires extra space for installation and repairment

Engineering Contradiction:
Improveslack detection capabilityVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The invention extracts the detection function from the traditional detector element and relocates it to the machine pulley housing. This allows the slack detection function to be integrated into the existing structure, eliminating the need for separate detector elements at both ends of the hoisting ropes and reducing installation space requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the slack detection function with the machine pulley housing by integrating the triggering arm mechanism directly into the housing structure. This combination eliminates the need for separate detector elements and reduces the overall space required for installation and maintenance.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If the detector element is connected to the ends of each hoisting rope, then the slack can be detected, but it can only detect high amount of slack after it gradually increases

Engineering Contradiction:
Improveslack detection capabilityVSAvoidslack detection sensitivity
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The invention introduces a triggering arm as an intermediary mechanism between the hoisting rope and the switching device. The triggering arm amplifies small deflections caused by minimal slack in the hoisting rope, enabling the switching device to detect even slight slack conditions that would be imperceptible with direct connection methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The triggering arm mechanism creates a periodic or threshold-based response to slack conditions. When the hoisting rope experiences any amount of slack, the triggering arm deflects and repeatedly actuates the switching device, ensuring that even minimal slack is detected and signaled immediately rather than waiting for gradual accumulation.

Inventive Principle:
Principle #19Periodic action

3Reliability

If a complex detector element with multiple components is used, then the slack condition can be detected, but the manufacturing cost and assembling cost increase

Engineering Contradiction:
Improveslack detection capabilityVSAvoiddetector structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the essential detection function from complex multi-component detector elements and implements it using a simple triggering arm mechanism integrated into the machine pulley housing. This extraction eliminates unnecessary components while retaining the core slack detection capability, thereby reducing manufacturing and assembly costs.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive, complex detector elements with a simple, inexpensive triggering arm mechanism that can be easily manufactured and replaced if needed. The simple mechanical design uses minimal materials and components, significantly reducing both manufacturing cost and assembly complexity while maintaining reliable slack detection functionality.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Reliability

If the switching device is directly interacted with by the traction medium, then the slack can be detected, but the detection response time increases

Engineering Contradiction:
Improveslack detection capabilityVSAvoiddetection response speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The triggering arm serves as a sensitive intermediary that immediately responds to any deflection in the hoisting rope caused by slack conditions. This intermediary mechanism transfers the motion from the rope to the switching device rapidly, enabling faster detection response compared to direct interaction methods that would require larger, slower-moving components.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The solution enables proactive detection of slack conditions, ensuring rapid actuation of the switching device even at minimal slack, reducing the risk of unsafe operations and enhancing operational efficiency and safety by allowing automated resetting to a tensioned condition indication.

Implementation Method 1

The triggering arm is adapted to be deflected by the traction medium when the traction medium is in a slack condition

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4671181A1A slack detection unit
Publication Date: 2025.12.31 INVENTIO AG
  • EP4671181A1 patent drawingFigure 1
  • EP4671181A1 patent drawingFigure 2a
  • EP4671181A1 patent drawingFigure 2b

AI summary

The slack detection unit (112) for a traction medium (114) of an elevator installation (100) is disclosed in the present invention. The slack detection unit (112) comprises a support bracket (202) adapted to be positioned at a machine pulley (108) guiding the traction medium (114). Further, the slack detection unit (112) comprises a triggering arm (204) attached to the support bracket (202). Furthermore, the slack detection unit (112) comprises a switching device (206) attached to the support bracket (202). The triggering arm (204) is adapted to be deflected by the traction medium (114) when the traction medium (114) is in a slack condition. A deflection in the triggering arm (204) actuates the switching device (206) to indicate that the traction medium (114) is in the slack condition.