Interference-Fit Fastener Tool for Grip-Safe Load Transfer

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Solution Overview

Problem

Existing tools for inserting fasteners into structures without damaging them are not adapted for fasteners with gripping elements, as they fail to apply force effectively without causing damage to the fastener or the structure.

Innovation Solution

A tool comprising a first body with a load transmission surface and a housing that allows for the application of force to the fastener's head and sleeve flange, transferring the load to facilitate interference fit without damaging the fastener, featuring a groove, U-shaped neck, and radially flexible fingers to accommodate the gripping element, along with a second body that complements the first body for enhanced load transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a traditional telescopic tool with clamping means is used to insert a fastener, then the fastener can be held during attachment, but the tool cannot accommodate fasteners with gripping elements without causing damage

Engineering Contradiction:

Improveadaptability to fasteners with gripping elementsVSAvoiddamage to fastener

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The tool is divided into two separate bodies: a first body that holds the fastener and a second body that applies the insertion force. This segmentation allows each body to be optimized for its specific function, enabling the tool to accommodate fasteners with gripping elements without causing damage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A load transmission surface is introduced as an intermediary element between the second body and the fastener. This surface transfers the insertion force from the second body through the fastener's head and gripping element to the structure, enabling force application without direct contact that could damage the fastener.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If force is applied directly to the fastener head, then insertion into the bore is achieved, but the fastener or structure may be damaged

Engineering Contradiction:

Improveinsertion efficiencyVSAvoiddamage to structure

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The load transmission surface is designed beforehand to distribute the insertion force across multiple contact points (head and sleeve flange). This pre-planned force distribution prevents concentration of stress that could damage the fastener or structure during insertion.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

Different parts of the load transmission surface are designed with different properties: one area contacts the fastener head while another area contacts the sleeve flange. This localized differentiation allows optimal force distribution tailored to each component's requirements, preventing damage while maintaining insertion efficiency.

Inventive Principle:

Principle #3Local quality

3Device complexity

If a single body tool is used, then the structure is simple, but the load transfer to fasteners with gripping elements is ineffective

Engineering Contradiction:

Improvetool structureVSAvoidload transfer effectiveness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The tool is segmented into two bodies with distinct functions: the first body provides a housing and load-bearing surface for holding the fastener, while the second body applies the insertion force. This segmentation, though increasing structural complexity, enables reliable load transfer to fasteners with gripping elements by providing dedicated force application and transmission paths.

Inventive Principle:

Principle #1Segmentation

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 the interference insertion of fasteners into structures without damaging them, ensuring the load is transferred effectively through the tool's designed surfaces, maintaining the integrity of the fastener and structure, and allowing for secure interference fit.

Implementation Method 1

A load applied to the first body is transferred directly to the fastener via the load transmission surface in contact with the head of said fastener

Methodology Applied

Scientific EffectForce transfer: Force

Implementation Method 2

The second end includes at least two radially flexible fingers

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS11772210B2Tool for inserting a fastener into a structure by interference and installation method for installing a fastener in a structure by interference using such a tool

Publication Date: 2023.10.03 LISI AEROSPACE

AI summary

A fastener installation tool and method for interference fit, said fastener (10) comprising a head and a grasping element, said tool comprising a first body (30) extending along a first main axis and having: —at least one load-reacting surface, of which one also constitutes a surface for the application of a load; —a load transmission surface, and—a housing extending along the first main axis from a first end of said first body, said housing being extended along the first main axis by a drilling extending from said housing as far as a second end of said first body. According to the invention, the load transmission surface is situated at the second end of the first body (30) and extends perpendicular to the first main axis, said load transmission surface being dimensioned to be able to bear simultaneously on the head and on the insert clamp.