Expansion Anchor Abutment Wall for High Pull-Out Resistance
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Solution Overview
Problem
Existing expansion anchors face challenges in achieving high performance while being easy to manufacture, and they often overstress the substrate due to high expansion forces, leading to premature pull-out failures and reduced concrete capacity.
Innovation Solution
The expansion anchor features an expansion body with at least one abutment wall recess, where the expansion sleeve abutment wall faces the expansion sleeve, creating a temporary form fit that increases pull-out resistance without significant expansion, thereby reducing substrate stress and enhancing concrete capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high expansion forces are used to increase pull-out resistance, then anchor performance is improved, but the substrate is overstressed leading to premature pull-out failures
Solution Approach 1:
The expansion sleeve abutment wall is pre-positioned on the expansion body to create a temporary form fit with the expansion sleeve before full expansion occurs. This preliminary interlock establishes pull-out resistance early in the expansion process, allowing the anchor to achieve high strength without requiring excessive expansion forces that would overstress the substrate.
Solution Approach 2:
The expansion sleeve abutment wall acts as an intermediary element between the expansion body and the expansion sleeve. It creates a controlled interaction point that generates form fit friction, serving as a mediator that transfers load from the expansion sleeve to the expansion body without requiring high expansion forces, thereby protecting the substrate from overstress.
2Adaptability or versatility
If the expansion sleeve is freely expandable to maximize concrete capacity, then anchor adaptability is improved, but relative movement between expansion sleeve and expansion body increases reducing performance
Solution Approach 1:
The abutment wall is pre-positioned to create a temporary form fit that limits relative movement between the expansion sleeve and expansion body during the expansion process. This preliminary constraint maintains stability and reduces slippage while still allowing the expansion sleeve to expand sufficiently to achieve concrete capacity, balancing adaptability with stability.
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 significantly improves anchor performance by increasing pull-out loads and reducing relative movement between the expansion sleeve and expansion body, especially in cyclic load conditions, while maintaining low expansion forces to avoid overstressing the substrate.
Implementation Method 1
an expansion body (12) for the expansion sleeve (30) provided on the anchor bolt (10), in particular in the vicinity of the front end of the anchor bolt (10), having a converging zone (23) for expanding the expansion sleeve (30)
Implementation Method 2
This form fit can increase the resistance against pull-out of the expansion body out of the expansion sleeve
Implementation Method 3
When the tip of the expansion sleeve touches the expansion sleeve abutment wall, a kind of temporary form fit can be generated between the expansion sleeve and the expansion body
Data Source
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AI summary
The invention relates to an expansion anchor having an anchor bolt, an expansion sleeve surrounding the anchor bolt, and an expansion body located in a front region of the anchor bolt, wherein the expansion body has a converging zone for expanding the expansion sleeve. According to the invention, the expansion body has at least one expansion sleeve abutment wall facing the expansion sleeve. The invention also relates to a method for using such an expansion anchor.