Blind Rivet Locking Structure for Non-Destructive Removal

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Solution Overview

Problem

Existing blind rivet technologies require destruction and separation into multiple parts for disassembly, making it difficult to completely remove the rivet from a component assembly without damaging the components or leaving parts behind.

Innovation Solution

The blind rivet design incorporates a mandrel with radially outwardly projecting locking engagement elements and a rivet body with radially inwardly projecting locking stop elements, allowing the mandrel to be securely positioned in both expansion and removal positions without destruction, enabling non-destructive disassembly and complete removal from one side.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional blind rivet disassembly methods are used, then the rivet can be removed from the component assembly, but the rivet must be destroyed and separated into multiple parts, making complete removal difficult and time-consuming

Engineering Contradiction:
Improvedisassembly processVSAvoidrivet structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The mandrel is segmented into multiple functional sections: a gripping section with lateral gripping elements for tool engagement, a locking section with locking elements that engage with the rivet body, and a breaking section with a predetermined breaking point. This segmentation enables the mandrel to perform multiple functions (gripping, locking, breaking) while allowing complete removal as a single piece after disassembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mandrel transitions from a static fastening state to a dynamic disassembly state through controlled breaking at the predetermined breaking point. The locking elements dynamically engage and disengage from the rivet body during the disassembly process, enabling the mandrel to be pulled out completely after the gripping section breaks away from the rivet body.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the mandrel is designed with gripping section, locking section and breaking section, then complete removal of the rivet is enabled, but the device complexity increases

Engineering Contradiction:
Improvedisassembly completenessVSAvoidmandrel structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The mandrel is designed as a multi-functional component that integrates gripping elements for tool engagement, locking elements for secure positioning in the expanded state, and a predetermined breaking point for controlled separation. This multi-functionality is achieved within a single mandrel structure, reducing the need for multiple separate components or tools for disassembly.

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

Solution Approach 2:

The locking elements are positioned within the rivet body recess, with the mandrel nesting inside the rivet body during the fastening state. The gripping section extends beyond the rivet body head, creating a nested configuration where the functional sections are arranged along the longitudinal axis, allowing compact integration of multiple functions.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Strength

If locking elements are added to secure the mandrel in expanded state, then the rivet connection reliability is improved, but the disassembly process becomes more complex

Engineering Contradiction:
Improverivet connectionVSAvoiddisassembly operation
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The locking elements are pre-configured to automatically engage with the rivet body when the mandrel is pulled during disassembly. The predetermined breaking point is pre-weakened to facilitate controlled breaking at a specific location. These preliminary configurations enable the disassembly process to proceed automatically once the disassembly tool is engaged, reducing the complexity of the actual disassembly operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The locking elements self-engage with the rivet body during the disassembly process when the mandrel is pulled outward. The breaking section automatically breaks at the predetermined breaking point under the applied force, eliminating the need for separate breaking or cutting operations. This self-service mechanism simplifies the disassembly operation while maintaining secure fastening during normal use.

Inventive Principle:
Principle #25Self-service

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

This design allows for simple, quick, and non-destructive disassembly of the blind rivet, enabling complete removal from a component assembly without damaging the components or leaving parts behind, thus improving the efficiency and reliability of the disassembly process.

Implementation Method 1

The mandrel (4) is rotatable in the rivet body recess (3) in the circumferential direction

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the sleeve-shaped rivet shank section is compressed and radially expanded until the radially expanded rivet shank section engages behind the outer side of the components

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 3

the locking engagement element of the mandrel rests with a mounting locking surface facing away from the setting head section against a mounting surface of the locking stop element facing the setting head section and retains the mandrel in the expanded position

Methodology Applied
Scientific EffectMechanical locking: Mechanical Fastener

Data Source

PatentEP4571129A1Blind rivet and method of removing the blind rivet
Publication Date: 2025.06.18 LISI AUTOMOTIVE KKP
  • EP4571129A1 patent drawingFigure 1~3
  • EP4571129A1 patent drawingFigure 4~5
  • EP4571129A1 patent drawingFigure 6

AI summary

In a method for dismantling a blind rivet (1) with a rivet body (2) and a mandrel (4) mounted in a rivet body recess (3), it is provided that in a dismantling step the mandrel (4) fixed in an expansion position is rotated in the circumferential direction and the fixing of the mandrel (4) in the expansion position is released, that the mandrel (4) is displaced in the direction of a rivet body head (7) into a dismantling position and the sleeve-shaped rivet shank section (6) is thereby stretched and radially contracted until the rivet shank section (6) is no longer in positive engagement with a second outer side of a component arrangement facing away from a setting head section (5) of the rivet body (2), that the mandrel (4) is fixed in the dismantling position in such a way that the sleeve-shaped rivet shank section (6) of the rivet body (2) can no longer expand radially,and that the rivet body (2) is then pulled out of the recess in the component arrangement in the direction of the setting head section (5).