Expansion Anchor Buckling Sleeve for Variable Plasterboard Thickness

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Solution Overview

Problem

Existing expansion anchors struggle to provide stable and reliable anchoring, particularly in materials like plasterboard, due to limitations in adapting to varying thicknesses and maintaining structural integrity.

Innovation Solution

An expansion anchor design featuring a plastic core with a screw channel and a metal sleeve, equipped with articulated arms and expansion elements, allows for toggle-like buckling that adapts to the thickness of the fastening base, ensuring secure anchoring without pre-defined buckling points, and includes features for rotational stability and haptic feedback during installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional expansion anchors are used in plasterboard, then anchoring is achieved, but stable and reliable anchoring cannot be ensured due to inability to adapt to varying thicknesses

Engineering Contradiction:
Improveadaptability to varying thicknessVSAvoidstable and reliable anchoring
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The expansion anchor employs a dynamic buckling mechanism where the articulated arms can toggle between straight and bent configurations. This dynamic behavior allows the anchor to automatically adapt to different plasterboard thicknesses during installation, while maintaining reliable anchoring through the frictional connection created when the arms buckle against the hole wall.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The anchor utilizes change in geometric parameters during installation - specifically the transformation of the articulated arms from a straight configuration to a buckled configuration. This parameter change enables the anchor to adapt to varying thicknesses while ensuring stable anchoring through the resulting frictional contact.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If expansion anchors with pre-defined buckling points are used, then anchoring is achieved, but structural integrity is compromised and haptic feedback is unclear

Engineering Contradiction:
Improvestructural integrityVSAvoidhaptic feedback during installation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The articulated arms are divided into multiple segments connected by joints, allowing distributed buckling along the arm length rather than at a single pre-defined point. This segmentation maintains structural integrity while providing clear haptic feedback through the sequential engagement of joints during the buckling process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The anchor system is self-regulating during installation - the articulated arms automatically buckle at the appropriate position based on the plasterboard thickness, providing inherent haptic feedback without requiring pre-defined buckling points. The system serves itself by utilizing the installation force to trigger the buckling mechanism.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If metal sleeve with articulated arms is used, then adaptability to thickness is improved, but rotational stability may be compromised

Engineering Contradiction:
Improveadaptation to thicknessVSAvoidrotational stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The expansion anchor incorporates asymmetric features including a non-circular cross-section of the articulated arms and an offset expansion element. This asymmetry prevents rotation of the anchor within the hole while maintaining the ability of the articulated arms to buckle adaptively in the radial direction.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The frictional connection created when the buckled articulated arms contact the hole wall serves as an intermediary mechanism that simultaneously provides rotational stability and thickness adaptability. The friction force prevents rotation while the geometric configuration allows adaptive buckling.

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

The anchor achieves stable anchoring in plasterboard by adapting to its thickness, providing a secure frictional connection and maintaining structural integrity, even in fire conditions, with low installation force and clear haptic feedback.

Implementation Method 1

the core is compressed in such a way that, depending on the design of the drilled hole, the parts of the core located in the slots protrude from them in a bulge-like manner

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

the core has at least a partially hollow cylindrical shape... the core comprises a screw channel for inserting a screw

Methodology Applied
Scientific EffectPoisson's effect: Poisson's Effect

Implementation Method 3

the sleeve expands outward, securing the expansion anchor in a drilled hole in the anchoring base. The core is compressed in such a way that... the parts of the core located in the slots protrude from them in a bulge-like manner

Methodology Applied
Scientific EffectBuckling:

Implementation Method 4

ensuring secure anchoring... providing a secure frictional connection

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4402384B1Expansion anchor
Publication Date: 2025.07.02 FISCHERWERKE ARTUR FISCHER GMBH & CO KG
  • EP4402384B1 patent drawingFigure 1~2
  • EP4402384B1 patent drawingFigure 3~4
  • EP4402384B1 patent drawingFigure 5

AI summary

The invention relates to an expansion anchor (1), in particular for use in gypsum plasterboards, having a compressible core (4) made of plastic. An outer sleeve (16) made of metal is disposed around the core (4). The sleeve (4) has, in a bending region (K), bending arms (20) which extend in the longitudinal direction of the expansion anchor (1). The core (4) is shortened in the longitudinal direction as a result of a screw (8) being screwed into the expansion anchor (1). In the process, the core (4) presses against the bending arms (20) at one or more points (V, S), as a result of which defined outward bending of the bending arms (20) is initiated.