Elevator Car Blocking Latch With Integrated Position Sensing

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Solution Overview

Problem

Current elevator systems require complex and expensive mechanical blocking devices for stabilizing the elevator car during maintenance, which are difficult to install and occupy valuable shaft space, making them impractical for use in modern elevator systems.

Innovation Solution

A blocking device comprising a latch, latch guide body, and position switch, which is easily attachable to the car guide rail, allowing the car and its sling to be immobilized with few, simple, and cost-effective components, ensuring stable support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a position sensor is mounted on the blocking device to detect the position of the car, then the position detection reliability is improved, but the blocking device structure becomes more complex and the number of parts increases

Engineering Contradiction:
Improveposition detection reliabilityVSAvoidblocking device structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The position sensor is integrated into the latch structure by receiving the sensor in a curvature notch on the latch, merging the sensing function with the mechanical blocking component. This reduces the number of separate parts and simplifies the overall blocking device structure while maintaining reliable position detection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The latch serves multiple functions: it mechanically blocks the car at terminal positions and simultaneously provides a mounting structure (curvature notch) for the position sensor. This multi-functionality eliminates the need for separate mounting components and reduces structural complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If the latch is designed to engage with the car sling at terminal positions to prevent overtravel, then the safety function is improved, but the device complexity increases due to additional components like the blocking device and position sensor

Engineering Contradiction:
Improvesafety functionVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The mechanical blocking function and position sensing function are combined into a single integrated structure where the latch with its curvature notch serves both purposes, reducing the total number of parts while maintaining safety.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The curvature notch on the latch acts as an intermediary structure that accommodates the position sensor, allowing the sensor to be mounted without adding separate complex mounting mechanisms, thus reducing the overall number of parts.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4458753B1Blocking device for the car of an elevator system
Publication Date: 2026.05.20 WITTUR HLDG GMBH
  • EP4458753B1 patent drawingFigure 1
  • EP4458753B1 patent drawingFigure 2
  • EP4458753B1 patent drawingFigure 3

AI summary

Blocking device for the car of an elevator system, comprising a latch, a latch guide body and a position switch, wherein the latch lies displaceably in the latch guide body and, in the extended position, can engage in a latch receiving opening of a car sling, preferably embodied in the horizontal beam of the car sling, when the latch is at a correspondingly aligned height with respect to the latch receiving opening of the car sling, the blocking device with its latch guide body, which preferably carries the latch and the position switch, being mountable on the car guide rail of the elevator system, and the latch comprises a curvature notch on a horizontal edge of the latch, which can at least partially accommodate a position sensor of the position switch.