Plug-in nut with rear-latching lugs for tolerance compensation

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Solution Overview

Problem

Existing push-in nuts face challenges in securely fastening screws due to unintentional displacement of the inner body relative to the outer body, especially under pre-assembly forces greater than the counteracting force exerted by spring arms, leading to instability and potential misalignment.

Innovation Solution

The push-in nut design incorporates engagement means that fix the inner body in an end position using pre-assembly force, with spring arms and rear locking lugs that are radially flexible, allowing reliable screwing up to a pre-assembly force greater than the counteracting force, and featuring a displaceable mounting to compensate for tolerances and ensure secure fastening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the inner body is freely displaceable in the outer body without engagement means, then the assembly is simple and easy to manufacture, but the inner body may unintentionally displace under pre-assembly forces greater than the counteracting force of spring arms

Engineering Contradiction:
Improvesimplicity of structureVSAvoidstability of inner body position
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The engagement means (protrusions and recesses) are pre-configured on the inner and outer bodies to automatically engage when the inner body is inserted into the outer body. This preliminary structural arrangement prevents unintentional displacement during subsequent assembly operations without requiring complex additional components or assembly steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spring arms act as intermediary elements between the inner body and outer body, providing a controlled displacement mechanism. They allow the inner body to move axially during assembly while the engagement means prevent lateral displacement, mediating between the need for simplicity and the need for stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If spring arms with rear locking lugs are used to prevent displacement, then the inner body stability is improved, but the device complexity increases due to additional components and assembly steps

Engineering Contradiction:
Improveprevention of unintentional displacementVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring arms and locking lugs are integrated as a single functional unit with the inner body, eliminating the need for separate locking mechanisms. The spring arms are directly formed on or attached to the inner body, combining the functions of elastic retention and positional control into one component system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring arms serve multiple functions simultaneously: they provide elastic retention of the inner body, allow controlled axial displacement during assembly, and work with the locking lugs to prevent lateral movement. This multi-functionality reduces the need for additional specialized components.

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

3Adaptability or versatility

If the inner body is rotatably mounted in the outer body, then the assembly allows for tolerance compensation, but the structural stability decreases under high pre-assembly forces

Engineering Contradiction:
Improvetolerance compensation capabilityVSAvoidstructural stability under load
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The mounting arrangement transitions from a static fixed connection to a dynamic system where the inner body can rotate and displace axially within controlled limits. The spring arms and engagement means create a dynamic retention system that adapts to tolerance variations while maintaining stability under operational loads.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system allows controlled changes in positional parameters (axial displacement and rotation) of the inner body relative to the outer body. These parameter changes enable tolerance compensation during assembly while the engagement means ensure that parameter changes remain within stable operational ranges under pre-assembly forces.

Inventive Principle:
Principle #35Parameter changes

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 ensures the inner body remains securely fixed during screwing, providing a high pull-out force and preventing unintentional displacement, thus ensuring reliable and stable assembly and disassembly.

Implementation Method 1

spring arms that are resilient in the radial direction and are arranged in an associated guide groove over the entire displacement path

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2697523B1Plug-in nut
Publication Date: 2016.05.25 A RAYMOND & CO SCS
  • EP2697523B1 patent drawingFigure 1
  • EP2697523B1 patent drawingFigure 2
  • EP2697523B1 patent drawingFigure 3

AI summary

A plug-in nut (1) has an outer body (2) and an inner body (10) which is mounted in the outer body (2) such that it can be displaced in a rotationally fixed manner. On the inner body (10), rear-latching lugs (17) are formed on spring arms (16), which rear-latching lugs (17) fix an attachment component on a carrier part in a variable position of the inner body (10) in relation to the outer body (2), which variable position is assumed so as to compensate for tolerances, as soon as a screw has been screwed into a screw receiving space (11) of the inner body (10). This results in a secure hold with very simple handling.