Blind Rivet Insert Sealing Ring Retention During Installation

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Solution Overview

Problem

Blind rivet inserts, such as blind rivet nuts, lack sufficient mechanical strength and are prone to seal damage during installation due to vibration, friction, and pressure, leading to a loss of seal integrity, especially when exposed to external factors like water, gases, or chemical substances.

Innovation Solution

A blind rivet insert design featuring a bearing head with an annular flange, a shank with a deformable region and internal thread, and strategically positioned annular retaining grooves to securely hold a sealing ring, allowing for reliable fixation and shifting of the ring during installation without additional tools, ensuring a sealed connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the insert is lubricated for automotive needs or subjected to high-temperature surface treatments, then ease of installation or surface quality is improved, but the seal becomes more prone to detachment due to increased vibration and friction

Engineering Contradiction:
Improveease of installationVSAvoidseal retention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The seal is pre-positioned and retained in the groove on the collar before any lubrication or surface treatment operations. This preliminary securing ensures that even when vibration and friction increase during these operations, the seal remains firmly in place and cannot detach.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If additional retention mechanisms are added to secure the seal, then seal retention is improved, but device complexity increases

Engineering Contradiction:
Improveseal retentionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The collar serves multiple functions: it provides structural support, creates the seal contact interface, and incorporates the retaining groove for seal retention. By integrating the retention function into the existing collar structure rather than adding separate retention components, the patent avoids increasing device complexity while improving seal retention.

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

Solution Approach 2:

The patent merges the sealing function and the retention function into a single integrated structure. The groove is formed as part of the collar itself, combining what could have been separate components into one unified element, thereby maintaining simplicity while achieving reliable seal retention.

Inventive Principle:
Principle #5Merging (Combining)

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 design provides a reliable and sealed connection between the blind rivet insert and the component, maintaining mechanical strength and preventing seal detachment, even under conditions like automotive lubrication or high-temperature surface treatments.

Implementation Method 1

the sealing ring is reliably fixed by a friction connection within said retaining shank groove

Methodology Applied
Scientific EffectFriction connection: Friction

Implementation Method 2

a deformable region of the shank, as for example having a reduced wall thickness of the shank in comparison to the foot end section of the shank

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP3885589B1Blind rivet insert, a component with an installed blind rivet insert and method for installing such a blind rivet insert in a component opening
Publication Date: 2022.05.04 BOLLHOFF OTALU SA
  • EP3885589B1 patent drawingFigure 1
  • EP3885589B1 patent drawingFigure 2
  • EP3885589B1 patent drawingFigure 3~4a

AI summary

The present invention relates to a blind rivet insert comprising a bearing head forming an annular flange and a shank extending from an underside of the bearing head and comprising a head end, a foot end and a cylindrical bore extending in lengthwise direction from the head end to the foot end, and having a first bore segment near the foot end, provided with an internal thread, and a second bore segment near the head end whose diameter is greater than the diameter of the first bore segment, the wall surrounding the second bore segment forming a deformable region of the shank, wherein the underside of the bearing head comprises an annular underhead groove concentrically arranged to the shank and adapted for receiving a sealing ring in a mounted condition of the blind rivet insert, and only one annular retaining shank groove extends circumferentially around the shank, being arranged adjacent to the underside of the bearing head, and retaining the sealing ring in a preloaded position before mounting the blind rivet insert.