Elevator Car Blocking Latch With Z-Profile Rail Receiver

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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 standard safety switches are not feasible.

Innovation Solution

A blocking device with a latch, latch guide body, and latch receiver, which is simple in design and consists of few parts, allowing the elevator car to be securely immobilized using a centrally guided system with a latch that displaces into a latch receiver when aligned, and a position switch attached to the car or sling, connected to the elevator controller.

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 immobilized, but the device complexity and installation difficulty increase

Engineering Contradiction:
Improvecar immobilization stabilityVSAvoidblocking device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The blocking device is divided into separate functional components: a latch mechanism mounted on the car that engages with a latch receiver mounted on the guide rail. This segmentation allows each component to be simple and independent, reducing overall device complexity while maintaining reliable immobilization through the engagement interface between latch and receiver.

Inventive Principle:
Principle #1Segmentation

2Reliability

If standard safety switches are used for car blocking, then the car can be stabilized, but the space requirements and installation difficulty increase due to limited space in the elevator shaft

Engineering Contradiction:
Improvecar blocking safetyVSAvoidelevator shaft space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The blocking mechanism transitions from using space-consuming safety switches to a mechanical latch system that operates in a different dimensional space - the latch engages with the guide rail structure itself, utilizing the vertical and lateral dimensions of the rail rather than requiring horizontal space for switches and actuators.

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

3Reliability

If complex blocking devices with many parts are used, then the car can be securely blocked, but the manufacturing cost and installation time increase

Engineering Contradiction:
Improvecar blocking reliabilityVSAvoidblocking device manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The latch mechanism integrates multiple functions into a single component - it provides both the blocking action and the engagement interface with the guide rail. The latch receiver is similarly combined with the guide rail structure, eliminating the need for separate mounting brackets and fastening systems, thereby simplifying manufacturing and installation.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4488214B1Blocking device for the car of an elevator system
Publication Date: 2025.08.13 WITTUR HLDG GMBH
  • EP4488214B1 patent drawingFigure 1
  • EP4488214B1 patent drawingFigure 2
  • EP4488214B1 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 car4), being mountable on a sling (27) of the car, characterized in that the latch receiver (5) is at least partially designed as a Z-profile or step-profile having a longer and a shorter horizontal leg.