Internal Door Latch Linkage for Compact Mechanical Security

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Solution Overview

Problem

Existing vehicle cabin door latching systems face security vulnerabilities due to electronic lock systems that can be disabled externally, and mechanical latching systems are bulky, intrusive, and insufficiently user-friendly, impacting perceived security and design constraints.

Innovation Solution

An internal latch system with a base and clasp assembly forming an articulated polygon, featuring a deployment linkage with parallel axes, allowing the clasp to deploy from a retracted to a deployed position, ensuring secure hooking on a cabin abutment member, and utilizing a bistable spring mechanism for stable positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional electronic locking systems are used, then ease of operation is improved, but reliability deteriorates due to vulnerability to external disabling

Engineering Contradiction:
Improveease of operationVSAvoidreliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The locking system is divided into two independent parts: an electronic locking system for convenience and a separate mechanical latching system for security. The mechanical latch includes a clasp assembly with deployment linkage that operates independently of electronic systems, providing segmented functionality where each part addresses specific requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A mechanical intermediary system (the mechanical latch with clasp and deployment linkage) is introduced between the door and cabin abutment member to provide a reliable physical connection that cannot be disabled electronically. This intermediary mechanical system acts as a backup that ensures reliability when electronic systems may fail.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If additional mechanical latching systems are added, then reliability is improved, but device complexity increases

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The mechanical latch components (base, clasp assembly, deployment linkage) are merged into a single integrated unit that forms an articulated polygon. This combining of multiple elements into one cohesive mechanism reduces overall system complexity while maintaining the reliability benefits of a mechanical latching system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The articulated polygon structure serves multiple functions: it provides the mechanical latching action, ensures proper alignment through geometric constraints, and enables reliable engagement with the cabin abutment member. This multi-functionality reduces the need for separate alignment and positioning mechanisms.

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

3Reliability

If mechanical latching systems are added, then reliability is improved, but volume increases due to bulky components

Engineering Contradiction:
ImprovereliabilityVSAvoidvolume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The clasp assembly is designed to nest within or adjacent to the door structure when not in use, and the deployment linkage folds or retracts to minimize space occupation. The articulated polygon allows compact storage of the mechanical latch components while maintaining full functionality when deployed.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The mechanical latch system transitions from a static bulky structure to a dynamic compact mechanism. The deployment linkage enables the clasp assembly to move between retracted and deployed positions, allowing the system to occupy minimal space during normal operation while providing full mechanical latching capability when needed.

Inventive Principle:
Principle #15Dynamics

4Reliability

If mechanical latching systems are added, then reliability is improved, but ease of operation deteriorates due to user-friendliness issues

Engineering Contradiction:
ImprovereliabilityVSAvoidease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The mechanical latch system is designed to operate automatically or with minimal user input. The deployment linkage may be actuated by a simple user action that automatically triggers the latching sequence, eliminating the need for complex manual manipulation while ensuring reliable mechanical engagement.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4711565A1Safety lock for door panel
Publication Date: 2026.03.18 VOLVO TRUCK CORP
  • EP4711565A1 patent drawingFigure 1~2
  • EP4711565A1 patent drawingFigure 3~4
  • EP4711565A1 patent drawingFigure 5~9

AI summary

The invention relates to an internal latch (44) for internally latching a door (22) of a vehicle (10) with respect to a cabin abutment member (38) of the vehicle, comprising: - a base (50) which is configured for attachment to an internal side of the door (22); - a clasp assembly (52) comprising a clasp (54), where the clasp (54) exhibits, with respect to the base (50), a storage position and a latching position, and where the clasp assembly (52) is attached to the base (50) by a deployment linkage (56) allowing the clasp assembly (52) to deploy from a retracted position, when the clasp (54) is in the storage position, to a deployed position, when the clasp (54) is in the latching position, according to a deployment movement; wherein the base (50), the clasp assembly (52) and the deployment linkage (56) form an articulated polygon.