Motorized Door Lock Rod Sensing for Tamper-Resistant Operation

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Solution Overview

Problem

Existing door arrangements lack reliability and tamper-proof mechanisms, particularly in motorized locking systems, which can be manipulated externally.

Innovation Solution

A sensor device with an incremental encoder and two optical sensors is used to detect the movement of a pull or drive rod, providing a redundant and tamper-resistant mechanism by evaluating the output signals of both sensors to determine the direction and speed of movement, ensuring secure operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single optical sensor is used to detect pull rod movement, then the device complexity is low, but the reliability and tamper resistance are insufficient

Engineering Contradiction:
Improvereliability and tamper resistanceVSAvoidsensor device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating two identical sensor detection paths with separate optical sensors, each monitoring the same incremental encoder but through independent optical channels. This local duplication in the sensing mechanism provides redundancy and tamper resistance without redesigning the entire system, resolving the contradiction between reliability and complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements copying by using two optical sensors that both detect the same incremental encoder movements. This creates redundant detection paths where the output signals from both sensors can be evaluated for consistency, providing tamper resistance through signal comparison while maintaining relatively simple device architecture.

Inventive Principle:
Principle #26Copying

2Object-affected harmful factors

If the incremental encoder is arranged away from the pull rod for protection, then external manipulation is prevented, but the motion coupling complexity increases

Engineering Contradiction:
Improveexternal manipulation resistanceVSAvoidmotion coupling complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses an intermediate element as a mediator between the pull rod and the incremental encoder. This intermediate component mechanically couples the pull rod's linear movement to the encoder's rotational detection while allowing the encoder to be positioned in a protected area away from external manipulation, thus resolving the contradiction between protection and coupling simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies the nested doll principle by integrating the incremental encoder within the protected housing area of the motor drive unit, nesting the sensing mechanism inside the existing structure. This allows the encoder to be shielded from external manipulation while maintaining functional connection to the pull rod through the intermediate coupling element.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 tamper-proof operation of the door arrangement by preventing external manipulation and ensuring secure, automated locking and unlocking processes.

Implementation Method 1

the sensor device comprises two optical sensors which detect a movement of the incremental encoder

Methodology Applied
Scientific EffectOptical detection: Photoelectric Effect

Data Source

PatentEP4700198A1Door assembly, in particular house or balcony door assembly
Publication Date: 2026.02.25 GRETSCH UNITAS GMBH BAUBESCHLAGFABRIK
  • EP4700198A1 patent drawingFigure 1
  • EP4700198A1 patent drawingFigure 2
  • EP4700198A1 patent drawingFigure 3

AI summary

The invention relates to a door arrangement (10), in particular a house or balcony door arrangement, wherein a motor drive unit (38) is provided for driving a pull or drive rod, wherein a sensor device is provided for detecting a movement of the pull or drive rod, and wherein a motor drive unit can be activated depending on a movement of the pull or drive rod detected by means of a sensor device, wherein the sensor device comprises an incremental encoder coupled to the movement of the pull or drive rod, wherein the incremental encoder has incremental sections offset from one another along a movement of the incremental encoder, and wherein the sensor device comprises two optical sensors which detect a movement of the incremental encoder.