Torque-Limiting Gasket Fastener Interlock Assembly

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Solution Overview

Problem

Existing gasket systems with torque-limiting features are costly, complex, and time-consuming to produce, and require additional assembly steps, which increases production time and reduces throughput.

Innovation Solution

A sealing system where the torque-limiting feature is integrated into the fasteners rather than the gasket, allowing for preassembly of the gasket and fasteners with the gasket's apertures engaging the fasteners' shoulder portions to secure them together, eliminating the need for a torque-limiting feature in the gasket.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a torque-limiting feature is included in the gasket, then the gasket can prevent overcompression and preload fasteners, but the cost and complexity of the gasket increases

Engineering Contradiction:
Improveprevention of overcompressionVSAvoidgasket structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The torque-limiting function is extracted from the gasket and transferred to the fastener's shoulder portion. The gasket is simplified to only perform sealing, while the fastener's shoulder provides the torque-limiting feature by engaging with the gasket aperture to prevent overcompression and preload the fastener.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The fastener is given multiple functions: it provides both the sealing function (by engaging with the gasket aperture) and the torque-limiting function (via its shoulder portion). This eliminates the need for the gasket to independently provide torque-limiting capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a torque-limiting feature is included in the gasket, then the gasket can prevent overcompression and preload fasteners, but the number of assembly steps and tooling increases

Engineering Contradiction:
Improveprevention of overcompressionVSAvoidassembly process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The torque-limiting function is extracted from the gasket and transferred to the fastener's shoulder portion. The gasket is simplified to only perform sealing, while the fastener's shoulder provides the torque-limiting feature by engaging with the gasket aperture to prevent overcompression and preload the fastener.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a torque-limiting feature is included in the gasket, then the gasket can prevent overcompression and preload fasteners, but the production time increases and throughput decreases

Engineering Contradiction:
Improveprevention of overcompressionVSAvoidgasket production throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The torque-limiting function is extracted from the gasket and transferred to the fastener's shoulder portion. The gasket is simplified to only perform sealing, while the fastener's shoulder provides the torque-limiting feature by engaging with the gasket aperture to prevent overcompression and preload the fastener.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If the gasket is aligned with components during assembly, then the fasteners can be properly inserted, but the assembly process becomes time consuming

Engineering Contradiction:
Improveproper fastener insertionVSAvoidalignment time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The gasket is pre-assembled with the fasteners at a remote location before final installation. The fasteners are inserted through the gasket apertures and secured, creating a pre-assembled unit that requires minimal alignment during final installation, thus reducing assembly time at the final location.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The gasket and fasteners are merged into a single pre-assembled unit. The fasteners are inserted through the gasket apertures and retained by the gasket structure, creating a combined assembly that simplifies the final installation process by reducing the number of separate components to be assembled.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP1726852B1Coverpan gasket
Publication Date: 2011.07.27 CARL FREUDENBERG KG
  • EP1726852B1 patent drawingFigure 1
  • EP1726852B1 patent drawingFigure 2~3
  • EP1726852B1 patent drawingFigure 4~5B

AI summary

The present invention utilizes a gasket (26) that interlocks on a fastener (28) thereby enabling the fastener (28), the gasket (26) and a component to be connected together as an assembly. The fastener (28) includes a torque-limiting feature thereby freeing the gasket (26) from the necessity of including such a feature therein. The interlock between the gasket (26) and the fastener (28) is formed by tabs (46) that fit within a shoulder of the gasket (26) or by an interference fit between apertures (44) in the gasket (26) and the shoulder of the fasteners (28).