Drop-in Anchor Asymmetric Plug Friction Reduction
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Solution Overview
Problem
Existing drop-in anchors require substantial setting force, typically achieved with a sledgehammer, to secure the plug and expand the sleeve in masonry, which is inefficient and labor-intensive.
Innovation Solution
A drop-in anchor design featuring a tubular sleeve with raised surfaces at one end and a plug with a dissimilar angle, allowing for reduced friction and easier installation using fewer blows or even a standard hammer, and an optional retainer to prevent plug removal, along with a visual indication mechanism via abrasion of the installation tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a frustoconically shaped plug with angled surfaces is used to match the inwardly tapering inner wall of the sleeve, then insertion is made as easy as possible, 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 uses a cylindrical shape with asymmetric friction reduction features (raised surfaces or grooves) rather than a symmetric frustoconical shape. This asymmetric design reduces friction during insertion while maintaining ease of insertion, eliminating the need for substantial setting force with sledgehammer blows.
Solution Approach 2:
The invention changes the geometric parameters of the plug from a frustoconical shape with matching angles to a cylindrical shape with friction reduction features. This parameter change fundamentally alters the friction characteristics during insertion, reducing the setting force required while maintaining ease of insertion.
2Reliability
If a frustoconically shaped plug is used to match the inwardly tapering inner wall of the sleeve, then the angled surfaces work together to achieve the desired effect, but a relatively large number of blows with a sledge hammer is required
Solution Approach 1:
The cylindrical plug with asymmetric friction reduction features provides reliable engagement through a different mechanism than the traditional frustoconical shape. The raised surfaces or grooves create asymmetric friction characteristics that ensure reliable engagement while reducing the number of blows needed, thereby reducing installation time.
Solution Approach 2:
The friction reduction features on the cylindrical plug enable the insertion process to be more self-servicing, requiring less external force application. The plug essentially guides itself into the sleeve with reduced friction, eliminating the need for repeated sledgehammer blows and reducing overall installation time.
3Difficulty of detecting and measuring
If raised surfaces are added to the sleeve for visual indication of engagement, then confirmation of proper installation is simplified, but the device complexity increases
Solution Approach 1:
The raised surfaces on the sleeve are coated with a removable coating that abrasively wears off during proper installation. This color change from coated to uncoated state provides clear visual indication of engagement without adding complex mechanical indication mechanisms, maintaining simplicity while improving detectability.
Solution Approach 2:
The visual indication system is self-service in that the installation process itself creates the indication. As the plug is driven into the sleeve, the raised surfaces naturally abrade the coating, providing automatic visual confirmation of proper engagement without requiring separate indication devices or complex mechanisms.
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 design reduces the force required for setting the anchor, allowing successful installation with fewer blows and increased load-bearing capacity, while the retainer enhances security and the visual indication simplifies confirmation of engagement.
Implementation Method 1
The installation tool abrades on one or more raised surfaces of a sleeve of the drop-in anchor when the plug attains the installed position. A coating is removed from the one or more raised surfaces via the abrasion of the installation tool thereon
Data Source
AI summary
A drop-in anchor includes a tubular sleeve having a first end and an expandable second end, the sleeve having one or more raised surfaces at the first 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 and an installation tool interacts with the one or more raised surfaces to provide a visual indication of engagement of the drop-in anchor to a workpiece.