Dual-Section Dowel Structure for Stable Anchoring Across Base Types
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Solution Overview
Problem
Existing dowels struggle to provide effective anchoring in various types of anchor bases, including solid materials like concrete and perforated bricks, due to inconsistent holding values and insertion challenges.
Innovation Solution
A dowel design with two anchor sections arranged longitudinally, featuring rear expansion legs that are longer and more rigid than front expansion legs, allowing for greater anchoring force through elastic compression and radial pressure against the anchor hole walls, facilitated by a rocker mechanism and optional expansion elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single anchor section is used, then the structure is simple, but the holding values are inconsistent across different anchor bases
Solution Approach 1:
The anchor is divided into two distinct anchor sections (front and rear) with different structural characteristics. The front anchor section has expansion legs optimized for solid anchor bases, while the rear anchor section has expansion legs optimized for perforated anchor bases. This segmentation allows each section to specialize in different anchoring conditions, resolving the contradiction between reliability across varied bases and structural simplicity.
2Reliability
If expansion legs are made longer for better anchoring in perforated bases, then holding power increases, but insertion force increases
Solution Approach 1:
The front and rear anchor sections have different local qualities in terms of expansion leg length and rigidity. The front section has shorter, more flexible expansion legs optimized for solid bases with lower insertion force requirements, while the rear section has longer, more rigid expansion legs optimized for perforated bases where maximum anchoring force is needed. This local differentiation resolves the contradiction by providing context-appropriate characteristics in different locations.
3Ease of manufacture
If the anchor sections have equal diameter, then manufacturing is simpler, but radial pressure distribution is uneven in different base types
Solution Approach 1:
The front and rear anchor sections are designed with asymmetric diameters. The rear anchor section has a larger diameter than the front anchor section, creating an asymmetric structure that optimizes radial pressure distribution. The larger rear section provides greater radial pressure for perforated bases, while the smaller front section is sufficient for solid bases, resolving the contradiction between manufacturing simplicity and optimized pressure distribution.
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 dowel achieves enhanced anchoring performance in both solid and perforated materials by minimizing insertion force and maximizing retention, with the rear anchor section providing superior holding power in less solid bases and the front section facilitating entry into narrower holes.
Implementation Method 1
the two anchor sections are elastic in such a way that, when inserted into a cylindrical anchor hole whose diameter is smaller than one or the diameters of the anchor sections before insertion into the anchor hole, they are elastically compressed and bear against the wall of the anchor hole with an elastic pressure force
Implementation Method 2
By inserting a pin-shaped expansion element into the anchor sections, these can also be expanded, i.e., radially widened, to increase the anchoring force
Data Source
Figure 1
Figure 2~3
AI summary
The invention proposes constructing a dowel (1) with two anchor sections (4, 5) arranged one behind the other, which have opposing expansion legs (6, 7) that are curved outwards in a longitudinal direction (L). The rear expansion legs (7) are curved further outwards and are shorter, making them more rigid and providing a greater anchoring force in an anchor hole. In an anchor hole in a solid anchor base, anchoring with only one front anchor section (4) is sufficient. The expansion legs (6, 7) act as rockers such that a force exerted radially inwards on them alternately forces the expansion legs (6, 7) radially outwards, thus improving anchoring.