Blind Fastener Tapered Core Bolt for Angled One-Side Installation

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Solution Overview

Problem

Current blind fastener systems face challenges in complexity, manufacturing difficulty, integration with robotics, installation at varying angles, and cost, particularly when sealant adheres to the internal drive mechanism, making them hard to use in applications where access is limited or unavailable.

Innovation Solution

A blind fastener system comprising a sleeve and a core bolt with a tapered body that causes radial expansion of the sleeve when moved along its axis, allowing for easy installation and secure anchoring without requiring access to the opposite side, using materials with different hardness levels for enhanced performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional blind fastener systems are used, then fastening can be achieved from one side, but the installation process becomes complex and difficult to manufacture

Engineering Contradiction:
Improveone-sided installation capabilityVSAvoidinstallation process complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The fastening system is divided into distinct functional components: a fastener body with internal threading, a separate sleeve with external threading, and a drive mechanism. This segmentation allows each component to be optimized independently while simplifying the overall installation process through modular assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent inverts the traditional approach by having the sleeve thread onto the fastener body from the blind side, rather than requiring access from both sides. The expansion mechanism works by threading the sleeve onto the expanding bolt, causing radial expansion of the sleeve against the bore wall from the single accessible side.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If traditional blind fastener systems are used, then fastening can be achieved, but manufacturing becomes difficult and costly

Engineering Contradiction:
Improvefastening reliabilityVSAvoidmanufacturing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The fastener body serves multiple functions: it provides the internal threading for the sleeve, acts as the expansion mechanism through its threaded geometry, and functions as the anchoring element. This multi-functionality reduces the number of parts and simplifies manufacturing while maintaining fastening reliability.

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

Solution Approach 2:

The patent utilizes changes in thread pitch and diameter along the length of the fastener body to create the expansion effect. By varying these geometric parameters, the system achieves reliable anchoring through controlled radial expansion of the sleeve, eliminating the need for complex expansion mechanisms.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If sealant is applied to prevent leakage, then sealing is improved, but the internal drive mechanism becomes jammed or plugged

Engineering Contradiction:
Improvesealing capabilityVSAvoiddrive mechanism operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent separates the sealing function from the drive mechanism by positioning the sealant application area outside the internal drive mechanism's operational space. The sealant is applied to the external surfaces where it prevents leakage without interfering with the threading and expansion operations of the drive mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a sealant barrier that acts as an intermediary between the fastener components and the external environment. This sealant layer prevents leakage while being strategically positioned to avoid contact with the internal drive mechanism, thus preventing jamming or plugging.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Adaptability or versatility

If access to one side is difficult or unavailable, then blind fastening is required, but installation at varying angles becomes problematic

Engineering Contradiction:
Improveblind fastening capabilityVSAvoidinstallation at varying angles
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The fastening system incorporates dynamic elements that allow adaptation to varying installation angles. The threaded connection between the sleeve and fastener body, combined with the radial expansion mechanism, provides flexibility in accommodating non-perpendicular bore orientations while maintaining secure fastening.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs asymmetric geometry in the fastener body and sleeve design, with tapered sections and angled threading patterns that facilitate installation at varying angles. The asymmetric expansion profile allows the sleeve to engage the bore wall effectively regardless of the precise angle of insertion.

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 system simplifies installation, reduces manufacturing complexity, and enhances secure anchoring capabilities, making it suitable for applications where access is restricted and cost-effective, while allowing for integration with robotics and varied installation angles.

Implementation Method 1

the body is tapered from the distal end portion of the body to the proximal end portion of the body such that the core bolt causes radial expansion of the sleeve when the body is urged relative to the sleeve through the bore along the core bolt axis

Methodology Applied
Scientific EffectRadial expansion: Deformation

Data Source

PatentEP4148287B1Blind fasteners and associated methods for installing blind fasteners
Publication Date: 2024.12.04 THE BOEING CO
  • EP4148287B1 patent drawingFigure 1
  • EP4148287B1 patent drawingFigure 2
  • EP4148287B1 patent drawingFigure 3

AI summary

A blind fastener (100) includes a sleeve (110) having a distal end portion (110a) and a proximal end portion (110b) and defining a bore (160). The blind fastener also includes a core bolt (120) at least partially received in the bore of the sleeve, the core bolt defining a core bolt axis and including a body (122) having a distal end portion (122a) and proximal end portion (122b) axially opposed from the distal end portion, wherein the body is tapered from the distal end portion of the body to the proximal end portion of the body such that the core bolt causes radial expansion of the sleeve when the body is urged relative to the sleeve through the bore along the core bolt axis.