Foot-Operated Door Latch Linkage With Switchable Hand Override

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Solution Overview

Problem

Existing door-opening mechanisms, such as power-assisted electrical or mechanical openers, are complex, prone to malfunction, expensive, and require significant modifications, and lack of maintenance can lead to user injury, while manual door opening is inconvenient when hands are occupied or contaminated.

Innovation Solution

A foot-operated door-unlatching device with a foot-operated lower actuator connected to a hand-operated upper actuator via a link, allowing unlatching by foot or hand, with a configuration that can be switched between engaged and disengaged modes for secure operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If power-assisted electrical or mechanical door openers are used, then door opening convenience is improved, but device complexity and cost increase

Engineering Contradiction:
Improvedoor opening convenienceVSAvoidopener complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of automatic door opening by removing complex electrical/mechanical systems and retaining only the core mechanical linkage between foot pedal and door latch, significantly simplifying the device while maintaining convenience

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The door opener system uses the user's own foot power to directly actuate the door opening mechanism through a simple mechanical linkage, eliminating the need for external power sources, motors, or control systems

Inventive Principle:
Principle #25Self-service

2Ease of operation

If power-assisted door openers are installed, then door opening capability is improved, but installation modification requirements increase

Engineering Contradiction:
Improvedoor opening capabilityVSAvoidinstallation modification
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The system is divided into separate functional modules: a foot pedal assembly, a mechanical linkage, and a door latch interface, allowing independent installation and configuration without modifying the existing door structure

Inventive Principle:
Principle #1Segmentation

3Device complexity

If manual door opening is used, then device complexity is reduced, but ease of operation deteriorates when hands are occupied

Engineering Contradiction:
Improvedoor opening mechanismVSAvoidhand operation convenience
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent introduces a foot pedal as an intermediary actuation mechanism that translates foot motion into door latch movement, allowing hands-free operation while maintaining simple mechanical construction

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of operation

If foot-operated mechanism is added, then hand-free operation is improved, but device complexity increases

Engineering Contradiction:
Improvehand-free operationVSAvoidactuator mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The foot pedal and door latch actuation are merged into a single integrated mechanical linkage system, where the foot pedal directly drives the latch mechanism through a continuous mechanical connection, minimizing the number of separate components

Inventive Principle:
Principle #5Merging (Combining)

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

Enables convenient and hygienic door opening without requiring hand contact, reducing the risk of contamination and injury, while maintaining security through mode switching.

Implementation Method 1

an upper actuator (300) comprising a lever-arm (350) and a handle-mount (380)... wherein the lever-arm (350) is movable between a first position and a second position relative to the handle-mount (380)

Methodology Applied
Scientific EffectLever: Lever

Implementation Method 2

a link (400) coupled to the foot-pad (550) and the lever-arm (350)... actuation of the foot-pad (550) moves the lever-arm (350) and the handle-mount (380)

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP4127362B1Door-unlatching device
Publication Date: 2026.04.15 CHU DANIEL
  • EP4127362B1 patent drawingFigure 1A
  • EP4127362B1 patent drawingFigure 1B~1G
  • EP4127362B1 patent drawingFigure 1H~1M

AI summary

A door-unlatching device including a lower actuator including a foot-pad, an upper actuator including a lever-arm and a handle-mount attachable to a handle of door-latch, and a link coupled to the foot-pad and the lever-arm, wherein the lever-arm is movable between a first position and a second position relative to the handle-mount. It can be set to either engaged mode which allows either hand or foot to operate; or disengaged mode to allow only hand to operate which the door can also be locked from entry as by a normal door latch.