Articulated Walkway Frangible Threshold Mounting for Collision Safety
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Solution Overview
Problem
In railway vehicles, during low-speed collisions, the articulated walkway undergoes permanent deformation, posing a risk to passengers due to protruding metal parts, which can cause injuries from falling debris.
Innovation Solution
The walkway thresholds are mounted with frangible attachment systems that break during a collision, allowing them to slide relative to the car structures, preventing permanent deformation and reducing the risk of injury by absorbing energy without lifting into the passenger area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the walkway thresholds are rigidly fixed to the car structures, then the walkway maintains structural stability during normal operation, but the thresholds undergo permanent deformation and protrude into the passenger area during collision
Solution Approach 1:
The attachment system is divided into separable components: a fastening system with detachable elements (such as shear pins or frangible bolts) that connect the threshold to the car structure. During collision, these elements detach, allowing the threshold to move independently and absorb impact energy without deforming into the passenger area, while maintaining stable connection during normal operation.
Solution Approach 2:
The attachment system transitions from a static rigid connection to a dynamic system that can change its state. The frangible fastening elements are designed to break at a specific force threshold, transforming the connection from fixed to movable during collision, allowing the threshold to slide or retract safely without permanent deformation.
2Strength
If the walkway thresholds are rigidly fixed to the car structures, then the attachment system maintains strong connection during normal operation, but the thresholds experience permanent deformation during low-speed collision
Solution Approach 1:
The fastening system uses sacrificial frangible elements (such as shear pins or breakable bolts) that are designed to break during collision. These elements are replaced after impact, allowing the expensive threshold structure to be preserved without deformation while the inexpensive fastening elements absorb the impact energy through controlled failure.
Solution Approach 2:
The frangible fastening system is pre-designed with a controlled failure mechanism that activates before the threshold can deform. The fastening elements are engineered to break at a specific force level, providing advance protection to the threshold structure by transferring impact energy to the sacrificial elements rather than allowing deformation of the precision-critical threshold.
3Reliability
If the walkway thresholds are rigidly fixed to the car structures, then the fastening system maintains secure attachment during normal operation, but the thresholds lift into the passenger area during impact
Solution Approach 1:
The fastening system transitions from a static secure connection to a dynamic release mechanism. During normal operation, the frangible fastening elements maintain reliable attachment. During impact, the elements break in a controlled manner, allowing the threshold to move safely without lifting into the passenger area, thus maintaining reliability when needed and preventing harm when impact occurs.
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 effectively reduces passenger risk by absorbing impact energy and preventing the walkway from deforming into the passenger zone, thus minimizing the danger of falling debris during and after collisions.
Implementation Method 1
the first fastening system being frangible and configured to break when the first car and the second car pass from the limit configuration to the close configuration
Implementation Method 2
the first threshold is mounted sliding and fixed on the first structure by a first fastening system
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A vehicle (10) comprising: - a first and second car (12, 14) arranged successively in a longitudinal direction (L), - a hinged gangway (16) to allow passengers to move between the first and second cars, and comprising a first threshold (28) mounted on the first car, a second threshold (30) mounted on the second car, and a central section (32). The first and second cars are mobile in the event of a collision between a normal configuration, in which the gangway is in a deployed configuration, a limit configuration, in which the gangway is retracted, and a close-coupled configuration. The first threshold is slidably mounted and fixed to the first structure by a first frangible fastening system (34) configured to break when the first and second cars move from the limit configuration to the close-coupled configuration.