Commercial Vehicle Mirror Rotary Joint Segmentation

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Solution Overview

Problem

Existing mirror arrangements for commercial vehicles, such as those in low-floor buses, face challenges in securely fixing the mirror in an operating position while allowing it to pivot in both directions for safety and withstanding wind forces, resulting in complex and expensive structures.

Innovation Solution

A mirror arrangement with two rotary joints, each allowing pivoting in only one direction, with a stop mechanism and torsion springs to securely fix the mirror in an operating position and enable safe pivoting in both directions, using a simpler and cost-effective design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If friction or locking joints are used to securely fix the mirror in operating position while allowing pivoting in both directions, then the mirror can be safely protected in collision and people in safety area are protected, but the device complexity and cost increase significantly

Engineering Contradiction:
Improvemirror fixation reliabilityVSAvoidjoint structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The mirror support system is divided into two separate rotary joints (first and second rotary joints), each responsible for one direction of rotation. This segmentation allows each joint to have a simpler structure optimized for unidirectional movement, while collectively providing bidirectional protection capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The two rotary joints are combined to work together as a unified system. The first rotary joint handles pivoting in one direction while the second handles the opposite direction, merging their functions to achieve comprehensive collision protection without requiring each individual joint to be complex.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a single joint allows pivoting in both directions with stable fixing, then collision protection is provided, but the manufacturing cost increases

Engineering Contradiction:
Improvecollision protection capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of manufacturing one complex bidirectional joint, the system uses two simpler unidirectional joints. Each joint can be manufactured using standardized, cost-effective processes, reducing overall manufacturing complexity and cost while maintaining collision protection reliability.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If torsion springs are used to enable pivoting in permissible direction and secure fixation, then the structure becomes simpler and cost-effective, but the resistance to wind forces must be adequately designed

Engineering Contradiction:
Improvejoint structure simplicityVSAvoidwind force resistance
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The torsion spring parameters (coil diameter, wire diameter, number of turns, material properties) are optimized to provide the precise balance needed between enabling smooth pivoting motion and maintaining sufficient resistance to wind forces. This parameter tuning allows a simple spring mechanism to handle both requirements.

Inventive Principle:
Principle #35Parameter changes

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 provides a stable and secure fixation of the mirror in its operating position, allowing safe pivoting in both directions, effectively preventing damage during collisions and withstanding wind forces, while reducing complexity and cost.

Implementation Method 1

The first and/or second pivot joint can comprise a torsion spring. This allows pivoting in the permissible direction of rotation in a structurally simple and cost-effective manner and, on the other hand, fixes the mirror head securely in its operating position. In addition, it allows the mirror head to safely return to its operating position after an evasive movement.

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentEP1726482B1Vehicle mirror apparatus, in particular for commercial vehicles
Publication Date: 2008.03.26 MEKRA LANG GMBH & CO KG
  • EP1726482B1 patent drawingFigure 1
  • EP1726482B1 patent drawingFigure 2
  • EP1726482B1 patent drawingFigure 3A~3C

AI summary

The arrangement has two swivel joints (3, 4) that are arranged between a supporting arm and a mirror head, where a rotation axis (31) of one joint extends horizontal and transverse to a driving direction and a rotation axis (41) of the other joint extends parallel to the driving direction. The joint (3) allows a swiveling of the mirror head around its rotation axis only in a direction of rotation and the joint (4) allows the swiveling of the mirror head around its rotation axis only in another rotation direction. An independent claim is also included for a commercial vehicle e.g. person bus, comprising a mirror arrangement.