Composite Expansion Dowel Structure for Solid and Hollow Wall Anchoring
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Solution Overview
Problem
Existing expansion dowels made entirely of low-rigidity plastic materials provide inadequate anchoring to walls, especially in partially perforated or hollow materials, and fail to ensure complete screw coupling and retraction, leading to ineffective anchoring.
Innovation Solution
The expansion dowel features a tubular body with high resistance to deformation and alternating longitudinal inserts with low resistance to deformation, allowing controlled deformation in two perpendicular directions, ensuring robust anchoring to various support types through independent expansion sectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tubular body is made entirely of low-rigidity plastic material, then radial expansion and anchoring to the wall are improved, but screw coupling and retraction capability deteriorate
Solution Approach 1:
The dowel body incorporates alternating longitudinal sections of low-rigidity material (for expansion and anchoring) and high-rigidity material (for screw coupling). This local differentiation allows each region to perform its specific function optimally without compromising the other.
Solution Approach 2:
The dowel uses a composite structure with alternating sections of plastic materials having different rigidity characteristics. The low-rigidity sections enable radial expansion while the high-rigidity sections provide structural support for screw engagement, creating a material composite solution.
2Strength
If additional rigid elements are attached to the tubular body, then screw coupling is improved, but anchoring to partially perforated or hollow walls deteriorates
Solution Approach 1:
Instead of adding separate rigid elements to a flexible body, the invention segments the dowel into alternating rigid and flexible longitudinal sections. This segmentation allows the flexible sections to expand radially for anchoring while the rigid sections provide screw coupling, eliminating the conflict between the two functions.
Solution Approach 2:
The dowel structure implements local quality by assigning different rigidity properties to different longitudinal sections. The low-rigidity sections are positioned to enable expansion in hollow walls, while high-rigidity sections are positioned to provide screw coupling, optimizing each region for its specific function.
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 achieves satisfactory anchoring to both solid and hollow supports by ensuring effective screw coupling and controlled deformation, enhancing the dowel's robustness and anchoring capabilities.
Implementation Method 1
the screw radially deforms the tubular body of the dowel, with resulting increase in the dowel section, thus causing locking of the dowel inside the wall
Data Source
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AI summary
The present invention relates to an expansion dowel (1). Said expansion dowel (1) comprises a body (3) made of a plastic material with a first resistance to deformation and provided with at least one pair of longitudinal sections (3a) alternating with respective longitudinal inserts (11), diametrically opposite to each other, made of a plastic material with a second resistance to deformation. According to the invention, the expansion dowel (1) can pass form a first, non-deformed configuration, in which the diametrically opposite longitudinal inserts (11) are substantially parallel to each other and the diametrically opposite longitudinal sections (3a) are parallel to each other, to a second, deformed configuration, in which said diametrically opposite longitudinal inserts (11) move away from each other at their middle portion and said diametrically opposite longitudinal body sections (3a) move away from each other at their middle portion. Thanks to the features set forth above, the expansion dowel according to the invention is robust and ensures satisfactory anchoring thereof to any type of support, and particularly to solid, perforated or hollow supports.