Elevator Cabin Position Detector with Redundant Wheel Sensors

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Solution Overview

Problem

Existing elevator braking systems face issues with reliability, maintenance complexity, and cost due to mechanical and electronic solutions, which fail to accurately control speed and prevent overspeeding, especially in high-speed elevators and multi-storey buildings, and require extensive installation efforts.

Innovation Solution

A detector device using two wheels with redundant detection and autonomous energy supply, mounted on guide rails with tension springs, providing accurate speed monitoring and emergency braking, and capable of detecting wear and contamination, ensuring reliable operation and easy installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical speed governor with a cable running through the entire shaft is used, then the system works purely mechanically and cannot be affected by electronic failures, but it is prone to failure due to wear, has high construction costs, and takes up space along the entire shaft

Engineering Contradiction:
Improveresistance to electronic failuresVSAvoidconstruction complexity and cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical cable-based speed governor with an electronic detector device that uses a sensor (such as a magnetic or optical sensor) to detect the speed of the elevator car. This substitution eliminates the need for a cable running through the entire shaft, reducing construction complexity and cost while maintaining reliability through electronic sensing rather than mechanical contact

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the essential function of speed detection from the complex mechanical cable system and implements it through a compact electronic sensor mounted on the elevator car. This extraction removes the unnecessary cable infrastructure while preserving the core functionality of monitoring elevator speed and triggering brakes when necessary

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If a mechanical speed governor is used, then the system is simple in structure, but it is not possible to specify different maximum permissible speeds for different sections of the shaft without special measures

Engineering Contradiction:
Improvestructural simplicityVSAvoidability to specify different maximum speeds for different shaft sections
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic speed control by allowing the maximum permissible speed to be adjusted based on the elevator car's position in the shaft. The electronic detector device can receive position information and dynamically modify speed limits for different sections (e.g., lower speeds near floors, higher speeds in intermediate zones), providing adaptability without increasing structural complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters (speed limits) based on position data. By monitoring the elevator car's location through the detector device, the system can vary speed parameters across different shaft sections, enabling differentiated speed control for safety and efficiency without requiring mechanical modifications

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a mechanical speed governor with inertial masses is used, then the system is straightforward to implement, but the triggering speed is noticeably dependent on the acceleration, causing late triggering under high acceleration conditions

Engineering Contradiction:
Improveimplementation simplicityVSAvoidspeed measurement accuracy under acceleration
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces the acceleration-dependent mechanical inertial mass system with an electronic sensor-based speed detection system. This substitution eliminates the coupling between acceleration and speed measurement, allowing accurate speed detection regardless of the elevator car's acceleration state, thereby improving measurement precision while maintaining implementation simplicity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Strength

If the governor rope is heavily soiled, then the mechanical structure remains intact, but it may not be triggered until the speed is very excessive

Engineering Contradiction:
Improvestructural integrityVSAvoidtriggering reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent replaces the soiling-prone mechanical governor rope with an electronic sensor system that is immune to contamination. The sensor (magnetic or optical) detects speed through non-contact means, eliminating the risk of soiling affecting triggering reliability while maintaining the structural integrity of the mechanical components

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enhances the reliability and ease of installation of elevator braking systems, providing accurate speed control and emergency braking, while reducing maintenance complexity and costs, and ensuring safe operation in high-speed elevators and multi-storey buildings.

Implementation Method 1

Two wheels (9), which are held in rockers (10), are provided, wherein the wheels (9) rest on guide rails (2) in a frictional contact

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2043935B1Position detector of an elevator cabin
Publication Date: 2014.04.16 WITTUR HLDG GMBH
  • EP2043935B1 patent drawingFigure 1a~1b
  • EP2043935B1 patent drawingFigure 2~3
  • EP2043935B1 patent drawingFigure 4a~4d

AI summary

The invention relates to a lift comprising a lift cage which is guided in a shaft along guiding rails, said lift comprising an electronic system, inter alia, for controlling or regulating the running of the lift, and an emergency braking device for preventing the lift cage from overspeed. The emergency braking device comprises a braking device and a detector device (11) which emits a signal for actuating the braking device in the event of overspeed of the lift cage. The detector device (9, 11) comprises at least two wheels which are arranged on a guiding rail (2) and each drive a detector (11) emitting a signal which is a measure for the rotational angle or rotational speed. The electronic system is embodied in such a way that it functionally uses the detector signals, in that at least one detector signal is examined during the operation of the lift within the authorised speed range in order to determine at least one path, speed and/or acceleration variable influencing the subsequent operation of the lift installation, and in that the electronic system actuates the braking device as soon as at least one of the detectors (11) announces an overspeed of the lift cage outside the authorised speed range, by means of the detector signal thereof.