Blind Rivet Bolt Asymmetric Hexagonal Insert Crimping

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Solution Overview

Problem

Existing blind crimp bolt assembly methods face challenges such as insufficient tightening to prevent insert rotation during screwing, potential damage to threads, increased assembly costs due to separate crimping and screwing operations, and difficulties in aligning screws with inserts, leading to inefficiencies and potential damage to components.

Innovation Solution

A bolt comprising a screw and an insert with a breaking ring that immobilizes the screw during crimping, allowing for single-operation crimping and screwing, and featuring a locking mechanism to prevent insert rotation, along with a washer for reduced friction and a tubular element for radial expansion to facilitate crimping and assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional crimp nut assembly method is used, then the insert can be fixed to the wall, but the tightening between the head of the insert and the nut is insufficient to prevent the insert from rotating during screwing

Engineering Contradiction:
Improveprevention of insert rotationVSAvoiddifficulty of assembly
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The insert head is designed with an asymmetric hexagonal shape that engages with a corresponding hexagonal socket in the crimping tool. This asymmetric geometry provides mechanical engagement that prevents rotation of the insert during the crimping operation, while still allowing the insert to be freely rotated during manual installation if needed.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The crimping tool is designed to apply uniform radial compression forces around the entire circumference of the insert head simultaneously. This equipotential distribution of crimping force ensures even deformation of the insert material, creating consistent friction and mechanical interlocking with the wall material, thereby preventing rotational movement during subsequent screwing operations.

Inventive Principle:
Principle #12Equipotentiality

2Ease of manufacture

If the crimping tool pulls between the nut and the insert head, then the insert can be crimped to the wall, but the tool can damage the thread of the nut

Engineering Contradiction:
Improvecrimping capabilityVSAvoidthread integrity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

A specially designed crimping tool with a hexagonal socket interface is introduced as an intermediary between the operator and the insert. This tool engages with the hexagonal socket in the insert head and transmits crimping forces through controlled mechanical contact points that are positioned to avoid the threaded portion, thereby preventing thread damage while achieving effective crimping.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The crimping forces are applied locally at specific contact points on the insert head that are geometrically positioned away from the threaded region. The insert head geometry is designed with a distinct separation between the crimping engagement zone (hexagonal socket area) and the threading zone, allowing independent access to each function without interference.

Inventive Principle:
Principle #3Local quality

3Productivity

If the nut is put in place and then a screw is introduced later, then the assembly can be completed, but time passes during which dirt can get into the nut and disturb the screwing

Engineering Contradiction:
Improveassembly efficiencyVSAvoidscrewing operation quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The insert is pre-installed into the wall substrate during the initial assembly phase, creating a ready-to-use threaded receptacle. This preliminary action ensures that the threading environment is established before any subsequent screwing operations, minimizing the window of opportunity for contamination and ensuring optimal threading conditions are present from the start.

Inventive Principle:
Principle #10Preliminary action

4Ease of operation

If separate operations are organized for crimping and screwing, then the assembly can be completed, but the assembly cost increases

Engineering Contradiction:
Improveassembly process flexibilityVSAvoidassembly cost
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The crimping and screwing operations are merged into a single integrated assembly sequence. The insert is first installed into the wall, then the crimping tool is applied to secure the insert, and finally the screw is introduced—all in one continuous operational flow without requiring separate tooling setups or distinct workstations. This merging eliminates redundant handling and positioning operations, reducing overall assembly time and cost.

Inventive Principle:
Principle #5Merging (Combining)

5Manufacturing precision

If a screw is aligned in the axis of the thread of an insert, then the assembly can be completed, but it is not always easy to align the screw and this increases the difficulty and risks of assembly

Engineering Contradiction:
Improvescrew-insert alignmentVSAvoidassembly difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The insert head features an asymmetric hexagonal socket that engages with a corresponding hexagonal drive tool. This asymmetric geometry provides inherent alignment guidance, as the hexagonal interfaces can only mate in one orientation, automatically ensuring that the insert is properly oriented before the screw is introduced, thereby eliminating alignment difficulties.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

A hexagonal socket interface is introduced as an intermediary alignment mechanism between the insert and the assembly tool. This intermediate geometric feature provides mechanical guidance and constraint, ensuring that the insert is correctly positioned and oriented before the final screwing operation, thereby simplifying the overall alignment process.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 efficient, single-step assembly of accessories on walls with varying thicknesses, reduces assembly costs, and simplifies the process by eliminating separate operations, ensuring secure and durable attachments while minimizing thread damage and misalignment issues.

Implementation Method 1

said screw comprises a breaking ring, designed to, by resting on said insert head, directly or indirectly, immobilize said screw with respect to said insert head in order to operate by rotation of the screw the deformation of the recess and to obtain said crimping

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

operate by rotation of the screw the deformation of the recess and to obtain said crimping

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 3

designed to, once the crimping has been carried out, cause a rupture so as to release the screw with respect to the said insert head

Methodology Applied
Scientific EffectFracture Mechanics: Fracture Mechanics

Data Source

PatentEP2702280B1Blind rivet bolt
Publication Date: 2016.05.18 G FORCE
  • EP2702280B1 patent drawingFigure 1~3
  • EP2702280B1 patent drawingFigure 4~7
  • EP2702280B1 patent drawingFigure 8~10

AI summary

The invention relates to a bolt (1), including a screw (3) and an insert (2) which can be inserted in the opening (19) of a wall (5), said insert (2) comprising an insert head (6), and a shaft (7) including a recess (8), said insert head (6) and said recess (8) being configured such as to, after deforming the recess (8), crimp said insert (2) on said wall (5). Said screw (3) comprises a break ring (14), designed for engaging with said insert head (6), directly or indirectly, with a view to deforming the recess (8) by rotating the screw and thus to obtain said crimping, and designed such that, once crimping is complete, said ring breaks and releases the screw (3) from said insert head (6), thus making it possible to clamp an accessory (4) to the wall (5). The invention also relates to an assembly method using a bolt (1) according to the invention.