Composite Expansion Anchor for Stronger Screw Coupling
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Solution Overview
Problem
Expansion anchors made of homogeneous plastic material face issues with low rigidity, leading to inadequate screw coupling and anchoring, particularly in walls with low compactness or internal voids, resulting in insufficient tightening torque and incomplete anchoring.
Innovation Solution
The anchor features a deformable tubular body with integrated rigid inserts and reinforcing rings, providing higher mechanical rigidity and effective self-threading, along with anti-rotation fins to enhance screw engagement and prevent deformation during insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the anchor is made of homogeneous plastic material with low rigidity, then the tubular element has sufficient deformability and flexibility for radial expansion, but the screw coupling onto the tubular element becomes weak and inadequate
Solution Approach 1:
The anchor combines a soft plastic tubular element with a rigid plastic insert made of different materials having complementary properties. The soft plastic provides deformability for radial expansion, while the rigid insert provides structural strength for screw coupling, creating a composite structure that resolves the contradiction between softness and rigidity.
Solution Approach 2:
Different regions of the anchor have different mechanical properties: the tubular element is made of soft plastic for deformability, while the insert is made of rigid plastic for strength. This local differentiation of material properties allows each region to perform its specific function optimally without compromising the other.
2Adaptability or versatility
If the plastic material has low rigidity to ensure deformability, then radial expansion is good, but the tightening torque on the screw becomes insufficient for correct anchoring
Solution Approach 1:
The rigid plastic insert embedded in the soft tubular element provides the necessary structural strength to generate sufficient tightening torque on the screw, while the soft tubular element maintains its deformability for radial expansion. The composite structure enables both low rigidity for expansion and high strength for torque generation.
3Ease of operation
If the screw is progressively screwed into the longitudinal through opening, then self-threading should occur, but surface abrasion on the internal wall causes increase and damage of the internal section
Solution Approach 1:
The rigid plastic insert provides a stable, wear-resistant surface for screw threading, preventing the surface abrasion that would occur on soft plastic alone. The insert's higher rigidity and wear resistance protect the internal wall from damage while still allowing the screw to self-thread effectively.
Solution Approach 2:
The rigid insert acts as an intermediary between the screw and the soft tubular element. It provides a stable threading surface that prevents direct abrasion of the soft plastic, mediating the interaction between the screw and the deformable tubular element to prevent surface damage.
4Adaptability or versatility
If the anchor is fixed onto walls with low compactness or internal voids, then the retraction causes deformation inside the wall, but the low rigidity determines insufficient tightening torque from the plastic knotting
Solution Approach 1:
The rigid plastic insert embedded in the soft tubular element provides the necessary structural strength to generate sufficient tightening torque on the screw, while the soft tubular element maintains its deformability for radial expansion. The composite structure enables both low rigidity for expansion and high strength for torque generation.
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 a strong, effective anchoring with increased tightening torque, preventing screw uncoupling and surface damage, while allowing for various screw sizes and materials, and maintaining structural integrity in diverse wall types.
Implementation Method 1
comprises a deformable tubular element in which a longitudinal through opening is obtained, capable of accommodating a fastening screw therein which is adapted in use to radially deform the anchor so as to increase the section thereof
Implementation Method 2
made of a first plastic material; and at least one rigid insert integrated in the deformable body and made of a second plastic material having a mechanical rigidity higher than the mechanical rigidity of the deformable body
Implementation Method 3
anti-rotation fins to enhance screw engagement and prevent deformation during insertion
Implementation Method 4
effective self-threading, along with anti-rotation fins to enhance screw engagement and prevent deformation during insertion
Data Source
Figure 1
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Figure 3
AI summary
An expansion anchor (1) comprising a tubular body (2), which extends along a longitudinal axis (A) and is structured so as to have a head (4) at one end, adapted to be engaged inside a hole obtained in a wall; the head (4) comprising a deformable body (6) made of a first plastic material having a predetermined mechanical rigidity, and at least one longitudinal rigid insert (7), which is firmly integrated in the deformable body (6) and is made of a second plastic material having a higher mechanical rigidity than the mechanical rigidity of the plastic material of the deformable body (6) itself.