Door Guard Pivoting Lever Segmentation for Reliable Detection

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Solution Overview

Problem

Existing door guards for emergency exit doors are often perceived as bulky, cumbersome, and expensive, with complex designs that complicate installation and operation, particularly in emergency situations, and lack aesthetic appeal.

Innovation Solution

A door guard design where the housing is stationary relative to the door leaf, utilizing a pivoting lever that protrudes from the housing to detect the actuation of the operating element, allowing for easy assembly and operation without the need for precise alignment, and incorporating a tilting image display for visual alerts independent of electrical power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the housing is designed to pivot or slide out of the pivoting path of the operating element, then the door guard can detect door opening attempts, but the design becomes more complex and requires precise alignment

Engineering Contradiction:
Improvedetection reliabilityVSAvoidhousing mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The door guard is segmented into a stationary housing and a separate pivoting lever. The housing remains fixed while the lever independently pivots to detect operating element movement, eliminating the need for complex housing displacement mechanisms and precise alignment requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pivoting lever acts as an intermediary between the operating element and the sensor device. It translates the movement of the operating element into a detectable pivoting motion, allowing the stationary housing to reliably detect door opening attempts without requiring the housing itself to move.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the door guard uses a displaceable housing to detect operating element actuation, then it can monitor door status, but installation becomes complicated and time-consuming

Engineering Contradiction:
Improvemonitoring functionVSAvoidinstallation ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By separating the housing from the detection mechanism (pivoting lever), the system becomes modular and easier to install. The stationary housing requires no precise alignment, while the pivoting lever is independently positioned to contact the operating element, significantly simplifying the installation process.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the door guard housing blocks the pivoting path of the operating element, then it can prevent improper opening, but it becomes bulky and less aesthetically pleasing

Engineering Contradiction:
Improvedoor protection functionVSAvoidaesthetic appearance
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The detection function is separated from the housing structure and assigned to a thin pivoting lever. This allows the housing to maintain a sleek, aesthetically pleasing design while the lever provides the necessary monitoring function with minimal visual impact.

Inventive Principle:
Principle #1Segmentation

4Reliability

If the door guard requires precise alignment of the pivoting/sliding housing with the operating element, then it can function correctly, but the manufacturing and assembly requirements increase

Engineering Contradiction:
Improvedetection accuracyVSAvoidalignment precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The system separates the housing (no alignment needed) from the pivoting lever (self-aligning through pivoting motion). The lever naturally positions itself during pivoting to contact the operating element, eliminating the need for precise pre-alignment during manufacturing and assembly.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2309082B1Door monitoring device
Publication Date: 2014.03.19 ASSA ABLOY SICHERHEITSTECHNIK GMBH
  • EP2309082B1 patent drawingFigure 1~2
  • EP2309082B1 patent drawingFigure 3~4
  • EP2309082B1 patent drawingFigure 5a~5c

AI summary

The door guard (1) has a sensor device (10) for detecting a pivoting position of an operating element (8) in a fixed pivoting area. A controller (11) switches the door guard between a monitoring condition, a prealarm condition and an alarm condition depending on the detected pivoting position. The sensor device has a pivoting lever (13) pivotably supported around an axis (14), where the lever projects over a housing (9) and stands in effective connection with the operating element such that pivoting of the lever takes place in the pivoting area by pivoting the operating element.