Leaf Spring Guard Band for Rupture Safety

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Solution Overview

Problem

Current spring devices for vehicle wheel axles are heavy and lack sufficient redundancy to maintain vehicle stability and roadworthiness when a spring leaf breaks, leading to potential caster angle issues and damage to components like the brake cylinder.

Innovation Solution

A spring device featuring a guard band that encloses the loop of a single-leaf spring, combined with a clamping unit to link the guard band to the leaf spring, which keeps the spring together even upon rupture, preserving yaw stability and preventing upward shift of the wheel axle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple interconnected leaf springs are used to provide safety redundancy, then reliability is improved, but weight increases

Engineering Contradiction:

Improvespring safety redundancyVSAvoidspring link weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The guard band is divided into multiple segments (first guard band portion and second guard band portion) connected by a connection element, allowing the safety function to be distributed across separate components rather than requiring multiple full leaf springs

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The guard band acts as an intermediary safety component that works with the single leaf spring to provide redundancy functionality without requiring multiple leaf springs, thereby reducing weight while maintaining reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Weight of moving object

If a single-leaf spring is used to reduce weight, then weight is reduced, but reliability deteriorates when breakage occurs

Engineering Contradiction:

Improvespring device weightVSAvoidspring safety redundancy

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The guard band is pre-installed alongside the leaf spring to provide immediate protective function in case of breakage, cushioning the safety risk before it materializes into a hazardous situation

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The guard band serves as a mediator that compensates for the lack of inherent redundancy in a single-leaf spring design, providing the necessary safety backup without requiring multiple spring leaves

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If the guard band does not closely follow the leaf spring, then manufacturing is easier, but stability deteriorates due to loop play

Engineering Contradiction:

Improveguard band installationVSAvoidloop play stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The guard band is positioned to closely follow the leaf spring specifically in the critical loop region, providing localized stability where it is most needed without requiring complex manufacturing throughout the entire structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The connection element adds a vertical dimension to the guard band structure, allowing it to maintain close proximity to the leaf spring loop and minimize play through three-dimensional positioning rather than just planar alignment

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP2992239B1Spring device and spring suspension

Publication Date: 2019.06.12 SCANIA CV AB

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Figure 5A~5B

AI summary

The invention relates to a spring device including a leaf spring and a guard band extending along two sides of the leaf spring and enclosing the loop, as well as a clamping unit linking the guard band with the leaf spring. The invention also relates to a spring suspension for a wheel axle for a vehicle, the spring suspension containing a spring device.