Blind Fastener Sleeve Flaring for Inaccessible-Side Joining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing blind fasteners face challenges in securely fastening workpieces when access to the blind side is difficult or impossible, as they lack effective mechanisms to engage and secure surfaces without direct visibility or tool accessibility.
Innovation Solution
A blind fastener design featuring a core pin with a threaded elongated shank and a deformable sleeve that forms a flared connection upon compression, allowing secure engagement with workpieces, even when the blind side is inaccessible, by using a combination of materials like stainless steel and aluminum alloy for enhanced durability and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional blind fastener is used to secure workpieces when the blind side is inaccessible, then the fastening function is limited, but the reliability of secure engagement is insufficient
Solution Approach 1:
The fastener is divided into two distinct components: a core pin with head and a separate sleeve. The core pin can be inserted through both workpieces from the accessible side, while the sleeve is subsequently driven over the core pin to form the flared connection on the blind side. This segmentation allows installation without direct access to the blind side while ensuring reliable engagement through the flared geometry.
Solution Approach 2:
The core pin is first inserted through both workpieces to establish the baseline position and create alignment holes. This preliminary action prepares the assembly for the subsequent sleeve installation, ensuring that the sleeve will be properly positioned and aligned before the flared connection is formed on the blind side.
2Reliability
If a deformable sleeve is compressed by the core pin head to form a flared connection, then secure engagement with the blind side is achieved, but the structural complexity increases
Solution Approach 1:
The sleeve is designed with a deformable portion that changes its geometric parameters under compression. When the core pin head applies compressive force, the sleeve transitions from a cylindrical shape to a flared configuration with increased diameter. This parameter change enables the sleeve to expand and form a secure mechanical interlock with the blind side workpiece, achieving reliable engagement through controlled deformation rather than complex multi-component mechanisms.
3Strength
If different materials are used for the core pin and sleeve (e.g., stainless steel and aluminum alloy), then durability and flexibility are enhanced, but the manufacturing complexity increases
Solution Approach 1:
Different material properties are assigned to different components based on their specific functional requirements. The core pin is made from harder materials like stainless steel or alloy steel to provide structural integrity, threading capability, and resistance to deformation during installation. The sleeve is made from more ductile materials like aluminum alloy or brass to enable the necessary plastic deformation for forming the flared connection. This local quality differentiation optimizes the performance of each component while maintaining manufacturability through standard material selections.
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 fastener effectively secures workpieces together by forming a flared connection that resists movement, ensuring strong and reliable assembly without requiring direct access to the blind side, leveraging material differences for enhanced deformation and engagement.
Implementation Method 1
the deformable portion of the sleeve is configured to be deflected in response to compression of the deformable portion by the head of the core pin, such that the deformable portion forms a flared connection that engages a surface of one of the plurality of workpieces
Implementation Method 2
the threaded portion of the core pin of the fastener may additionally and/or alternatively include thread-forming external threads
Data Source
AI summary
A fastener includes a sleeve having a tubular portion including a first end and a second end; a head located at the first end; a deformable portion located at the second end; and a core pin having a first end and a second end. The core pin has an elongated shank portion between the first end of the core pin and the second end of the core pin including a threaded portion proximate the second end of the core pin and a head at the first end of the core pin. The sleeve is configured to receive the core pin. The fastener is configured to secure a plurality of workpieces to one another. The deformable portion is configured deflect in response to compression of the deformable portion by the head of the core pin, to form a flared connection that engages a surface of one of the plurality of workpieces.