Windscreen Wiper Arm Segmented Mounting Head Corrosion Prevention

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Solution Overview

Problem

Existing windscreen wiper arms are prone to corrosion at the interconnection of the mounting head and arm member, leading to potential blockage of pivotal movement and corrosion flow.

Innovation Solution

The design incorporates a partly open ring with interruptions around the transverse bush on the mounting head, allowing paint to enter between the mounting head and arm member surfaces, ensuring complete coverage and preventing corrosion, with a rivet pivot pin and plastic arm member for added protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the mounting head and arm member are connected with tight-fitting surfaces, then structural strength and stability are improved, but corrosion resistance deteriorates due to trapped moisture and lack of paint penetration

Engineering Contradiction:
Improvestructural strengthVSAvoidcorrosion resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The ring is segmented into a partly open structure with interruptions, dividing what would be a continuous barrier into discrete sections. This allows paint to penetrate through the interruptions to the interconnection surfaces while maintaining structural integrity and strength of the overall assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The ring structure is designed with different properties in different locations: the main body of the ring provides structural strength and stability, while the interruptions in the ring allow paint penetration and corrosion protection at specific critical locations (the interconnection surfaces between mounting head and arm member).

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If a closed ring is used around the transverse bush, then structural completeness is improved, but paint penetration capability deteriorates

Engineering Contradiction:
Improvestructural completenessVSAvoidpaint penetration capability
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The ring is intentionally designed as a partly open ring with interruptions rather than a complete closed ring. This segmentation maintains sufficient structural stability while creating pathways for paint to reach the interconnection surfaces between the mounting head and arm member.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The partly open ring acts as an intermediary structure that balances two competing requirements: it provides structural completeness and stability while simultaneously allowing paint penetration through its interruptions. The ring mediates between the need for structural integrity and the need for corrosion protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2790970B1Windscreen wiper arm
Publication Date: 2019.03.06 FEDERAL MOGUL SA
  • EP2790970B1 patent drawingFigure 1
  • EP2790970B1 patent drawingFigure 2~3
  • EP2790970B1 patent drawingFigure 4~5

AI summary

A windscreen wiper arm (1), particularly for automobiles, comprising a mounting head (2) mountable on a drive shaft (3) and an arm member (4) pivotally connected to the mounting head (2) by means of a pivot pin (5), wherein the arm member (4) has a substantially U-shaped cross-section near said pivot pin (5) comprising two side walls (6,7), wherein a part of the mounting head (2) extends between the side walls and beyond said pivot pin (5), and wherein said part is provided with opposite surfaces (8,9) each facing towards a respective side wall of the arm member (4), with the special feature that each surface of said part of said mounting head (2) is positioned spaced-apart from its respective side wall of said arm member (4), so as to allow paint to enter a space defined between each surface of said part of said mounting head (2) and its respective side wall of said arm member (4).