Three-Section Expansion Screw Bracing Mechanism
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Solution Overview
Problem
Conventional expansion screws with two-section strips fail to achieve a bracing effect when subjected to tensile force, leading to defective anchoring and damage to walls due to excessive compression on the rim of working holes, especially when the wall is thinner.
Innovation Solution
An expansion screw with at least three folding sections, where each strip has a first section inclined downwards, a second section forming an inner angle greater than 90° and connected to the first section, and a third section that braces the first section after expansion, allowing for a three-section folding and bracing effect to prevent wall damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional two-section strips are used in expansion screws, then the structure is simple, but the bracing effect cannot be achieved leading to defective anchoring and wall damage
Solution Approach 1:
The strip is divided into three distinct sections (first section extending from cap, second section connecting first and third sections, third section extending to head end) instead of conventional two sections. This segmentation enables the strip to fold and form a bracing effect during expansion, improving anchoring reliability while distributing compression forces more effectively to prevent wall damage.
2Strength
If the action zone is expanded outwards with two-section strips, then anchoring is achieved, but excessive compression occurs on the rim of working holes causing wall damage
Solution Approach 1:
The three-section strip structure segments the compression force application points along the strip length. During expansion, the folds at the connections between sections create multiple contact points with the wall, distributing the compressive load over a larger area and preventing excessive localized compression that damages the working hole rim.
Solution Approach 2:
The strip transitions from a flat two-dimensional configuration to a three-dimensional folded structure during expansion. The folds create angular relationships between sections that distribute forces in multiple directions, converting concentrated linear compression into distributed radial and axial forces, thereby reducing harmful compression on the working hole rim.
3Ease of manufacture
If two-section strips are used, then manufacturing is simple, but the strips cannot be folded and overlapped to achieve desired bracing effect
Solution Approach 1:
The strip is manufactured as a single piece with pre-formed connection zones between three sections, maintaining manufacturing simplicity while enabling the desired folded configuration. The segmentation allows the strip to be formed in one piece with controlled flexibility at section connections, achieving both ease of manufacture and reliable bracing effect through proper geometric design of the three sections.
4Force
If the action zone expands with two-section strips, then anchoring force is generated, but the strips remain in parallel without folding reducing clamping effectiveness
Solution Approach 1:
The three-section design with defined connection zones creates inherent fold points that guide the deformation pattern during expansion. This segmentation ensures the strip folds into a stable braced configuration rather than remaining parallel, maintaining both expansion force generation and configuration stability through the geometric constraints of the three-section structure.
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 three-section folding mechanism ensures secure anchoring by distributing compression evenly, preventing wall damage and enhancing construction quality by maintaining a firm contact with the wall surface without inverse penetration.
Implementation Method 1
the second section inclines gradually downwards and inwards... After expansion, the second section is, in use, folded and in contact with the first section
Implementation Method 2
The three-section folding mechanism ensures secure anchoring by distributing compression evenly, preventing wall damage
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An expansion screw (3) has at least three folding sections (311;313;315) to provide a bracing effect. It includes an anchor sleeve (30) and a bolt (34). The anchor sleeve (30) has a tubular body formed by rolling a plate and an action zone (31) in the middle portion. The action zone (31) has a plurality of longitudinal slots (316) and a plurality of strips (310). Each strip has a first section (311), a second section (313) and a third section (315). After the expansion screw (3) receives an action of a tensile force tool, the second section (313), due to having an upper end (312) and a lower end (314) that are weaker, can channel and concentrate stress to generate a bending and drive the first (311) and third (315) sections to bend in desired directions. Thereby the second section (313) is folded over the first section (311) and the third section (315) presses the first section (311) to form a bracing effect. The folding and bracing of the material can prevent defective construction and damage caused by excessive compression on the rim of the construction hole.