Washer Assembly Metal Reinforcement Rubber Isolation

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Solution Overview

Problem

Existing washer assemblies with rubber grommets face issues of permanent setting and reduced isolation effectiveness due to compression and degradation under increased loads, leading to movement and diminished protection of work-pieces.

Innovation Solution

A washer assembly featuring a rubber isolator with embedded or bonded metal strengthening members, such as a metal washer with regularly-spaced upsets or a wave-shaped design, which compresses during peak operating conditions to maintain isolation and prevent permanent setting, while the rubber isolator handles normal loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a rubber grommet is used to isolate the work-piece from the fastener, then the work-piece is protected from scratches and gouges, but the rubber grommet permanently sets under compression and loses isolation effectiveness over time

Engineering Contradiction:
Improveprotection from scratches and gougesVSAvoidisolation effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent combines rubber material with metal strengthening members to create a composite washer assembly. The rubber provides protection and isolation, while the metal members prevent permanent setting, resolving the contradiction between protective function and long-term reliability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The washer assembly is segmented into distinct functional components: the rubber isolator for protection and isolation, and metal strengthening members for structural support. This segmentation allows each material to perform its optimal function without compromising the other.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the rubber grommet is compressed to provide isolation, then the fastener and work-piece are isolated, but the compression causes permanent setting and height change over time

Engineering Contradiction:
ImproveisolationVSAvoidheight and shape
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The composite structure of rubber and metal allows the assembly to maintain its height and shape under compression. The metal strengthening members bear the compressive load, preventing the rubber from permanently deforming, thus maintaining both isolation and dimensional stability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The metal strengthening members are strategically positioned within the rubber isolator to provide localized support where compression forces are applied. This local reinforcement prevents permanent setting while maintaining the overall isolation function.

Inventive Principle:
Principle #3Local quality

3Device complexity

If the rubber grommet alone bears the load, then the assembly is simple, but the rubber degrades and becomes weak under increased loads and peak operating conditions

Engineering Contradiction:
Improveassembly structureVSAvoidload-bearing capacity
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The patent uses a composite of rubber and metal to achieve both simplicity and strength. The metal strengthening members are integrated into the rubber isolator, creating a unified component that maintains load-bearing capacity under both normal and peak operating conditions without significantly increasing assembly complexity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The metal strengthening members are pre-positioned within the rubber isolator during manufacturing, so they are already in place to support increased loads and peak operating conditions before the assembly is installed. This preliminary preparation ensures strength is available when needed without requiring complex assembly procedures.

Inventive Principle:
Principle #10Preliminary action

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 enhanced resistance to movement and compression, minimizing permanent setting and maintaining effective isolation over a wide range of forces, with the metal component preventing the rubber from excessive compression and extending its lifespan.

Implementation Method 1

a metal strengthening member permanently secured to the rubber isolator

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

The protuberance(s) is configured to be compressed during a normal operating condition

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

the rubber within the grommets 16 and 18 may degrade and become weak

Methodology Applied
Scientific EffectViscoelastic damping: Viscoelasticity

Data Source

PatentEP2668415B1Washer assembly
Publication Date: 2015.03.11 ILLINOIS TOOL WORKS INC
  • EP2668415B1 patent drawingFigure 1
  • EP2668415B1 patent drawingFigure 2~4
  • EP2668415B1 patent drawingFigure 5~6

AI summary

A washer assembly (60) is configured to isolate a work-piece from a fastener and/or another structure. The washer assembly includes a rubber isolator (62) having at least one protuberance (74) configured to directly contact a surface of the work-piece, and a metal strengthening member (40) permanently secured to the rubber isolator. The protuberance (s) (74) is configured to be compressed during a normal operating condition. The metal strengthening member (40) is configured to be compressed during a peak operating condition in which greater force is exerted into the washer assembly(60) than during the normal operating condition.