Pivot-Axis Fork Locking for High-Load Railway Hatches

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing locking/unlocking systems for railway vehicle components, such as doors or hatches, fail to absorb significant forces, leading to potential damage and safety risks, especially when subjected to mechanical stress, and lack robustness and reliability.

Innovation Solution

A locking/unlocking device with a pivot axis and a locking mechanism featuring parallel flats and a rotatable fork with arms that engage with the pivot axis to prevent rotation, allowing for robust and reliable operation under stress, including spontaneous locking in case of incorrect handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a Berne key locking system is used for pivoting elements, then the operation is simple and suitable for elements not subject to significant mechanical stress, but the system cannot absorb significant forces and lacks robustness

Engineering Contradiction:
Improveoperation simplicityVSAvoidforce absorption capability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The locking mechanism is segmented into distinct functional components: a pivot axis with flats for rotational movement, a separate locking axis with a fork mechanism for engagement, and a housing for structural support. This segmentation allows each component to be optimized for its specific function while working together to provide both ease of operation and strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention merges the simple rotational operation of a Berne key system with a robust mechanical locking fork that engages flats on the pivot axis. The fork mechanism combines with the pivot axis to create a unified locking system that maintains operational simplicity while adding significant force absorption capability through the engagement of the fork arms with the pivot axis flats.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a robust locking mechanism is implemented to transmit significant forces, then the device becomes reliable and durable, but the device complexity increases

Engineering Contradiction:
Improvelocking reliabilityVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism employs dynamic elements including a rotatable locking axis that can move between locked and unlocked positions, and a fork that rotates to engage or disengage from the pivot axis flats. This dynamic design allows the complex robust locking function to be achieved through simple rotational movements rather than complex multi-step operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The fork mechanism is designed to spontaneously return to the locked position through its own mechanical properties, such as gravity or spring tension, without requiring additional actuation. This self-service feature reduces the complexity of control systems while maintaining reliable locking, as the mechanism automatically ensures engagement when in the unlocked state.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If the pivot axis allows free rotation for operation, then the pivoting element can move between positions, but the system lacks spontaneous locking capability in case of incorrect handling

Engineering Contradiction:
Improverotational movement capabilityVSAvoidspontaneous locking capability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The pivot axis features asymmetric flats that engage with the fork arms in a specific orientation. The flats are positioned such that they allow rotational movement in one direction while providing positive engagement for locking. This asymmetric geometry enables the pivot axis to rotate freely for operation while automatically locking when the fork engages the flats, providing spontaneous locking capability without restricting necessary movement.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4585816A1Locking/unlocking device and pivoting element provided with such a locking/unlocking device
Publication Date: 2025.07.16 SNCF VOYAGEURS
  • EP4585816A1 patent drawingFigure 1
  • EP4585816A1 patent drawingFigure 2
  • EP4585816A1 patent drawingFigure 3

AI summary

The invention relates to a locking/unlocking device for a pivoting element comprising: - a pivot axis (3) integral in rotation with said pivoting element and having at least two flats (8, 9) extending parallel, - a locking mechanism, - a casing (1) configured to receive said pivot axis (3) and said locking mechanism, said locking mechanism comprising: ∘ a locking axis (4) extending orthogonally to said pivot axis (3), said locking axis (4) being movable in rotation, ∘ a member, called a fork (5), mounted on said locking axis (4), having two arms (25, 26) and movable in rotation between a locking position in which said arms (25, 26) extend in contact with said flats (9) of said pivot axis (3) preventing any rotation of said pivot axis (3), and an unlocking position of said pivot axis (3).