Fastening Device With Interlacing Blocking Cheeks For Pull-Out Resistance

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Solution Overview

Problem

Existing fastening devices for add-on parts to carrier parts do not achieve high pull-out forces with minimal movement of inner leg sections, leading to instability under shear forces.

Innovation Solution

The fastening device features overlapping tongue sections and a small distance between supporting cheek edges, allowing for distortion-free dimensional stability and high resistance to pull-out forces through interlacing and engagement of blocking cheeks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the inner leg sections are allowed to move significantly to absorb assembly tolerances, then the ease of assembly is improved, but the pull-out resistance and dimensional stability deteriorate

Engineering Contradiction:
Improveease of assemblyVSAvoidpull-out resistance
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The spring legs are designed with elastic inner leg sections that can dynamically adjust their position within a limited range to accommodate assembly tolerances, while the blocking cheeks provide a hard stop that prevents excessive movement. This dynamic design allows the fastening device to be easy to assemble while maintaining high pull-out resistance when properly installed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent optimizes the distance between the supporting cheek edges and the blocking cheek clearances to a specific small value. This parameter change ensures that the inner leg sections have minimal movement capability, which maintains dimensional stability and pull-out resistance while still allowing enough movement for practical assembly.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the distance between supporting cheek edges is reduced to improve pull-out resistance, then the strength is improved, but the manufacturing precision requirements worsen

Engineering Contradiction:
Improvepull-out resistanceVSAvoiddimensional tolerance
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies a small but non-zero distance between the supporting cheek edges and the blocking cheek clearances. This partial action provides sufficient pull-out resistance without requiring extremely tight manufacturing tolerances. The design accepts a small amount of clearance to avoid the need for excessive manufacturing precision while still achieving the desired strength.

Inventive Principle:
Principle #16Partial or excessive action

3Stability of the object's composition

If the tongue sections are designed to overlap extensively to improve interlacing, then the stability is improved, but the device complexity increases

Engineering Contradiction:
Improveinterlacing stabilityVSAvoidstructural complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The blocking cheeks are segmented into two separate tongue sections that overlap with each other. This segmentation creates an interlacing effect that stabilizes the spring legs against lateral movement. The segmented design achieves stability without requiring a completely different complex structure, as the tongue sections are simple extensions of the existing blocking cheeks.

Inventive Principle:
Principle #1Segmentation

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 configuration ensures high resistance to pull-out forces and maintains dimensional stability even under high shear forces, achieving reliable anchoring with minimal movement of inner leg sections.

Implementation Method 1

Each spring leg has an outer leg section and an inner leg section, which are connected to one another via a bent section

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2536958B1Fastening device
Publication Date: 2015.11.11 A RAYMOND & CO SCS
  • EP2536958B1 patent drawingFigure 1
  • EP2536958B1 patent drawingFigure 2
  • EP2536958B1 patent drawingFigure 3

AI summary

The invention relates to a fastening device having spring legs (4, 5) formed onto a cover plate (1), including support flanges (13, 14), which are disposed in support flange recesses (9, 10). The fastening element thereby has a very high pull-out force.