Elevator Car Blocking Latch for Compact Maintenance Immobilization

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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 due to limited space in the elevator shaft and often necessitate the use of large, complex safety switches, increasing system complexity and cost.

Innovation Solution

A blocking device comprising a latch, latch guide body, and latch receiver, which are easily mountable to the car guide rails and sling, allowing for simple and stable immobilization of the elevator car using a few, cost-effective components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex mechanical blocking devices are used to stabilize the elevator car, then the car can be securely fixed, but the device complexity and installation difficulty increase

Engineering Contradiction:
Improvestability of elevator carVSAvoidcomplexity of blocking device
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The blocking device is divided into separate components: a blocking element that can be inserted into the guide rail and a release element that triggers the unblocking mechanism. This segmentation allows each component to be simple in design while collectively providing reliable stabilization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the essential function of blocking from complex mechanical assemblies and implements it through a simple blocking element that engages with the guide rail geometry itself, rather than requiring additional complex mechanical structures.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If standard safety switches are used for detection, then the elevator car can be monitored, but the space requirements and system complexity increase

Engineering Contradiction:
Improvedetection reliabilityVSAvoidspace in elevator shaft
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The existing guide rail structure serves multiple functions: it provides structural support for the elevator car, serves as the blocking mechanism surface, and acts as the detection reference. This eliminates the need for separate detection devices that would consume additional space.

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

Solution Approach 2:

The guide rail structure performs the detection function for itself by providing geometric features that can be engaged by the blocking element. The system uses its own structural elements for both support and detection purposes, eliminating external detection devices.

Inventive Principle:
Principle #25Self-service

3Reliability

If multiple complex individual parts are used in the blocking device, then the blocking function can be achieved, but the manufacturing cost and installation difficulty increase

Engineering Contradiction:
Improveblocking functionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The blocking element and release element are designed as integrated components that work together through simple geometric interactions. This merging of functions into fewer components reduces manufacturing complexity and cost while maintaining reliable blocking functionality.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4357286B1Blocking device for the car of an elevator system
Publication Date: 2026.03.04 WITTUR HLDG GMBH
  • EP4357286B1 patent drawingFigure 1
  • EP4357286B1 patent drawingFigure 2
  • EP4357286B1 patent drawingFigure 3

AI summary

A blocking device for the car of an elevator system comprising a latch, a latch guide body, a position switch and a latch receiver, wherein the latch lies displaceably in the latch guide body and, in the extended state, can engage in a latch receiving opening of the latch receiver when the latch is at a correspondingly aligned height with respect to the latch receiving opening of the latch receiver, the latch receiver being mountable on a car guide rail, and the latch guide body, which preferably carries the latch and the position switch, being mountable on the sling of the car.