Drop-in Anchor Retainer and Segmented Plug Design
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Solution Overview
Problem
Existing drop-in anchors require substantial setting force to secure the plug and expand the sleeve, often necessitating multiple blows with a sledgehammer, and there is a risk of the plug being inadvertently removed before installation.
Innovation Solution
A retainer made of durable, moisture-resistant material is inserted into the sleeve behind the plug, engaging with internal threads to prevent removal and reduce the force required for setting, and a tubular sleeve with a dissimilar angle to the plug is used to minimize friction and maximize expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a frustoconically shaped plug is used with an inwardly tapering inner wall of the sleeve, then the angled surfaces work together to secure the sleeve in the hole, but substantial setting force is required normally obtained by the application of a relatively large number of blows with a sledge hammer
Solution Approach 1:
The plug is divided into two functional segments: a frustoconical leading end for insertion and engagement with the taper, and a cylindrical body portion for expansion. This segmentation allows the plug to insert easily while requiring less expansion force to set the anchor.
Solution Approach 2:
Instead of having the entire plug tapered to match the sleeve's inner wall, the invention inverts the approach by making only the leading end frustoconical while keeping the body cylindrical. This reversal reduces the surface area requiring high-friction engagement, thereby reducing the setting force needed.
2Ease of operation
If a frustoconically shaped plug is used to match the inwardly tapering inner wall of the sleeve, then insertion is made as easy as it can be, but substantial setting force is still required
Solution Approach 1:
The plug is divided into two functional segments: a frustoconical leading end for insertion and engagement with the taper, and a cylindrical body portion for expansion. This segmentation allows the plug to insert easily while requiring less expansion force to set the anchor.
Solution Approach 2:
Different portions of the plug have different geometries optimized for different functions: the leading end is frustoconical for easy insertion and engagement, while the body is cylindrical for controlled expansion. This local differentiation maintains insertion ease while reducing setting force requirements.
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 solution reduces the setting force needed to install the drop-in anchor, allowing for successful installation with fewer blows or even a standard hammer, and prevents inadvertent removal of the plug, enhancing the anchor's load-bearing capacity and installation efficiency.
Implementation Method 1
A retainer formed of a durable moisture-resistant material is insertable in the sleeve behind the plug, and is configured to be retained in the sleeve by the one or more threads
Implementation Method 2
A plug is insertable in the sleeve such that when the plug is driven into an installed position in the sleeve the second end expands
Data Source
AI summary
A retainer for a drop-in anchor includes a durable, moisture resistant member insertable into a sleeve of a drop-in anchor and configured to be retained in the sleeve by one or more threads disposed in the sleeve to prevent inadvertent removal of a plug from the sleeve. A drop-in anchor assembly includes a tubular sleeve having a first end including one or more internal threads, and an expandable second end. A plug is insertable in the sleeve such that when the plug is driven into an installed position in the sleeve the second end expands. A retainer formed of a durable moisture-resistant material is insertable in the sleeve behind the plug, and is configured to be retained in the sleeve by the one or more threads and prevent inadvertent removal of the plug from the sleeve.