Recessed Polygonal Washer for Co-Rotation Control in Fastening

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Solution Overview

Problem

Existing fastening methods using bolts or nuts can damage mounting surfaces due to simultaneous turning of washers, leading to paint peeling and surface roughness, requiring frequent maintenance and replacement of components.

Innovation Solution

A polygonal washer with a central recess on its mounting surface side, matching or exceeding the configuration of the nut or bolt head, allows elastic deformation to prevent simultaneous turning, minimizing surface damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a flat washer is used between the bolt head and mounting surface, then the mounting surface is protected from direct contact, but the washer may still co-rotate with the bolt and damage the mounting surface

Engineering Contradiction:
Improvemounting surface damageVSAvoidwasher rotation control
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention employs an asymmetric geometry where the washer body has a polygonal cross-section (triangle, quadrangle, pentagon, or hexagon) that does not match the circular rotation path of the bolt. This asymmetric shape prevents the washer from rotating with the bolt during tightening, as the polygonal form cannot align with the circular motion, thereby eliminating the harmful co-rotation effect that damages mounting surfaces.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The polygonal washer acts as an intermediary element between the rotating bolt and the stationary mounting surface. By introducing this intermediate component with a non-circular cross-section, the system decouples the rotational motion of the bolt from the mounting surface, allowing the bolt to rotate freely while the washer remains stationary and protects the surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the washer configuration matches the nut or bolt head configuration, then the taking turn suppression effect is improved, but the structure becomes more complex

Engineering Contradiction:
Improvesimultaneous turning controlVSAvoidwasher structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention employs an asymmetric geometry where the washer body has a polygonal cross-section (triangle, quadrangle, pentagon, or hexagon) that does not match the circular rotation path of the bolt. This asymmetric shape prevents the washer from rotating with the bolt during tightening, as the polygonal form cannot align with the circular motion, thereby eliminating the harmful co-rotation effect that damages mounting surfaces.

Inventive Principle:
Principle #4Asymmetry

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 polygonal washer prevents surface damage during tightening and loosening by controlling simultaneous turning, maintaining a simple structure and ensuring the mounting surface remains intact.

Implementation Method 1

the center portion of the washer body has the elasticity displaced to the mounting surface side is possessed

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4589159A1Square washer and fastening structure
Publication Date: 2025.07.23 NIPPON PLARAD CO
  • EP4589159A1 patent drawingFigure 1
  • EP4589159A1 patent drawingFigure 2(a)~2(c)
  • EP4589159A1 patent drawingFigure 3(a)~3(b)

AI summary

Provided are a asher that is simple structure and controls the simultaneous turning of the washer. Disclosed is a polygonal washer 1 is used between a mounting surface Sa of an object to be attached S and a nut 2 or a bolt head. The polygonal washer 1 comprises a washer body 1A. The washer body 1A has a polygonal shape, seen from an orthogonal direction against the nut 2. Central recess 1Aa is formed on the mounting surface Sa side. As for the configuration of the central recess 1Aa, it is equal to the configuration of the nut 2 or, it is equal to the head of a bolt, or it is formed more greatly than the nut 2 or it is formed more greatly than the configuration of the head of the bolt. As a result, when it is tightened with the nut 2 or the bolt, the center portion of the main body 1A of the washer has the elasticity displaced to the mounting surface side Sa is possessed.