Expansion Anchor Sleeve Web for High Pull-Out Without Bolt Weakening
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional expansion anchors with circular bolt cross-sections face a dilemma where increasing sleeve thickness for better anchoring reduces the bolt's breaking load, limiting load capacity without weakening the bolt.
Innovation Solution
Incorporating a web with local increased wall thickness and a corresponding groove in the bolt's neck area, allowing the web to rest on an inclined surface in the expansion area, enabling radial outward push and maximizing sleeve expansion without significantly weakening the bolt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sleeve thickness is increased to improve anchoring, then the anchorage to the borehole wall is improved, but the bolt diameter in the neck region must be reduced which reduces the bolt's breaking load
Solution Approach 1:
The expansion sleeve has a non-uniform wall thickness with a web region featuring locally increased wall thickness. This local quality variation allows the sleeve to achieve greater radial expansion capability at the web location for improved anchorage, while the bolt's groove is strategically positioned to accommodate this localized thickness increase without requiring a reduction in the overall bolt diameter, thus maintaining bolt strength.
2Length of moving object
If the sleeve thickness is increased to achieve greater maximum radial expansion, then the anchorage is improved, but the bolt diameter must be reduced to accommodate the thicker sleeve
Solution Approach 1:
The sleeve features a web with locally increased wall thickness that engages with a groove in the bolt's neck region. This localized thickness increase enables greater radial expansion at the web location while the groove accommodates this local variation without requiring a reduction in the overall bolt diameter, maintaining bolt strength.
Solution Approach 2:
The solution introduces a longitudinal dimension variation in the sleeve wall thickness through the web feature, rather than uniformly increasing thickness in all directions. This dimensional variation allows the sleeve to achieve greater radial expansion capability at specific locations while maintaining compatibility with the bolt's dimensional constraints.
3Force
If a large sleeve thickness is chosen to ensure good anchorage, then the pull-out values are improved, but the bolt diameter in the neck region must be reduced
Solution Approach 1:
The web region with locally increased wall thickness is positioned to engage with the groove in the bolt's neck region. This localized thickness increase provides enhanced pull-out resistance at the expansion interface, while the groove accommodates this local variation without requiring a reduction in the overall bolt diameter, thus maintaining bolt breaking load.
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 configuration achieves high load values with low production costs and high reliability by allowing a wide expansion without weakening the bolt, thus resolving the load capacity limitation.
Implementation Method 1
By drawing the expansion section of the bolt into the expansion sleeve, the sleeve is radially expanded, and the expansion anchor is anchored in the substrate.
Data Source
Figure 1~6
Figure 7~10
AI summary
The invention relates to an expansion anchor (1) with a bolt (10) having a neck region (11) and an expansion region (12) adjoining the neck region, in which the bolt tapers towards the neck region, wherein the bolt has a groove (15) in the neck region extending along the length of the bolt, and with an expansion sleeve (20) which at least partially surrounds the bolt and which has a web (25) on its inner side, wherein the web engages at least partially in the groove in the neck region, and wherein the wall thickness of the expansion sleeve is locally increased by the web, wherein the expansion sleeve is displaceable from the neck region into the expansion region along the bolt by radial expansion. According to the invention, when the expansion sleeve is displaced from the neck region into the expansion region, the web enters the expansion region at least partially and is forced radially outwards by the expansion region.