Blind Fastener with Removable Abutment for Damage-Free Extraction

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Solution Overview

Problem

Existing blind fasteners are difficult to remove from workpieces without causing damage, as the abutment member is swaged onto the pin and is integral with the sleeve, making it hard to drill out and potentially damaging adjacent parts.

Innovation Solution

A blind fastener design featuring a pin, sleeve, and abutment member where the sleeve has a radially expandable portion and a removable abutment member, allowing for easy installation and removal by applying axial compression to form a blind head that secures the workpiece, and subsequently allowing the abutment member to be detached for easy extraction of the pin and sleeve.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the abutment member is swaged onto the pin and made integral with the sleeve, then the fastener achieves strong mechanical engagement and secure installation, but the fastener becomes extremely difficult to remove without damaging the workpiece

Engineering Contradiction:

Improvemechanical engagement strengthVSAvoidfastener removability

Core Design Contradiction:

StrengthVSEase of repair

Solution Approach 1:

The fastener is divided into separate components: the abutment member is detached from the sleeve, allowing the sleeve and pin to be removed from the workpiece while the abutment member remains. This segmentation enables easy removal while maintaining secure installation during use.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The connection between the abutment member and sleeve transitions from a permanent swaged connection during installation to a detachable connection during removal. The abutment member can be removed from the sleeve after installation, changing the structural state from integrated to separable.

Inventive Principle:

Principle #15Dynamics

2Strength

If the pin is made hard to maintain strength during installation, then the fastener provides reliable mechanical engagement, but the pin becomes too hard to drill out for removal

Engineering Contradiction:

Improvepin strengthVSAvoidpin removability

Core Design Contradiction:

StrengthVSEase of repair

Solution Approach 1:

The pin is separated from the abutment member, allowing the pin and sleeve to be extracted from the workpiece as a unit without requiring drilling. The hard pin maintains its strength for secure installation but becomes removable through the detachment mechanism.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The abutment member is extracted or removed from the sleeve after installation, enabling the pin and sleeve to be pulled out through the aperture without damaging the workpiece. This extraction eliminates the need to drill out the hard pin.

Inventive Principle:

Principle #2Taking out (Extraction)

3Device complexity

If the abutment member is integral with the sleeve, then the fastener structure is simplified, but removal causes damage to adjacent workpiece parts

Engineering Contradiction:

Improvefastener structure simplicityVSAvoidworkpiece damage during removal

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The abutment member is separated from the sleeve, allowing the sleeve and pin to be removed without the abutment member. This prevents damage to adjacent workpiece parts that would occur if the integral abutment member remained attached during removal.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The abutment member is removed or extracted from the sleeve after installation, enabling clean removal of the pin and sleeve from the workpiece aperture without causing harm to surrounding areas.

Inventive Principle:

Principle #2Taking out (Extraction)

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

Enables convenient and damage-free removal of the fastener from a workpiece by ensuring the abutment member can be securely attached during installation but removed during disassembly, allowing the pin and sleeve to be easily pulled out through the aperture.

Implementation Method 1

the radially expandable part of the sleeve to radially expand to form a blind head in abutment with the remote face of the workpiece

Methodology Applied

Scientific EffectRadial expansion: Deformation

Implementation Method 2

apply compression to the workpiece between the blind head and the abutment member

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS7980800B2Blind fastener and method of removing it from a workpiece

Publication Date: 2011.07.19 AVDEL UK LTD

AI summary

A blind fastener for insertion through an aperture in a workpiece, the fastener including a pin, a sleeve and an abutment member; wherein the abutment member can be removed from the sleeve so that the pin and sleeve can be forced out of the aperture, to remove the fastener therefrom, wherein the sleeve has a radially expanding head, which is received in a recess of the abutment member and wherein, prior to insertion of the fastener into the workpiece aperture, the abutment member is secured to the sleeve by deformation of part of the abutment member adjacent the recess over and into contact with the sleeve head.