Self-Drilling Expansion Anchor with Cutting Thread
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Solution Overview
Problem
The existing expansion anchor setting process is complex and requires multiple tools, including a drill, hammer, and wrench, making it difficult and labor-intensive, especially in hard-to-reach areas.
Innovation Solution
An expansion anchor with a cutting thread on the anchor bolt that automatically screws into the borehole wall upon rotation, simplifying the installation process by eliminating the need for hammer blows and allowing the use of fewer tools, and a setting tool with a switchable clutch for efficient torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional expansion anchor is installed using hammer blows and multiple tools, then the anchor can be driven into the borehole, but the installation process becomes complex and labor-intensive
Solution Approach 1:
The patent combines the drilling function and anchoring function into a single self-drilling expansion anchor. The anchor bolt integrates a drill tip at its end, allowing it to drill its own borehole and then expand within the same hole, eliminating the need for separate drilling and anchoring operations and reducing the number of tools required
Solution Approach 2:
The self-drilling expansion anchor is designed to perform multiple functions autonomously. The drill tip enables the anchor to create its own borehole, and the expansion mechanism allows it to secure itself without external assistance, making the installation process simpler and more self-contained
2Ease of operation
If hammer blows are used to drive the anchor into the borehole, then the anchor can be installed, but the process becomes difficult in hard-to-reach areas
Solution Approach 1:
The patent replaces the conventional axial impact force (hammer blows) with a rotary drilling mechanism. The self-drilling anchor uses rotational motion to penetrate the substrate, which is much more effective in hard-to-reach areas where applying axial force is difficult. The drill tip is specifically designed to cut into the substrate through rotation rather than impact
3Ease of operation
If the cutting thread is designed to cut into the borehole wall, then the anchor can be screwed in with rotary motion, but the manufacturing cost may increase
Solution Approach 1:
The patent applies local quality by providing surface hardening only at the cutting thread region of the anchor bolt, rather than hardening the entire anchor. This localized treatment reduces manufacturing costs while still providing the necessary cutting capability at the critical engagement point with the borehole wall
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 significantly simplifies the setting process, reduces effort, and ensures high reliability by enabling self-drilling and self-tightening of the anchor with rotary movements, while maintaining high pull-out strength and low production costs.
Implementation Method 1
the cutting thread can cut into the cylindrical borehole wall in the subsoil. This allows the cutting thread to draw the anchor bolt into the borehole when the anchor bolt is rotated
Implementation Method 2
the load is still primarily borne by the expansion sleeve, which, after the anchor bolt has been screwed into the borehole, is expanded axially by drawing in the expansion section against the cylindrical borehole wall
Data Source
Figure 1
AI summary
The invention relates to an expansion anchor (1), in particular for mineral building materials, for example concrete. A generic expansion anchor is equipped with an expansion sleeve (10) for anchoring to a borehole wall and an anchor bolt (20) which runs through the expansion sleeve. The anchor bolt has an expanding region (27) for expanding the expansion sleeve. According to the invention, the anchor bolt has a cutting thread (30) for cutting into the borehole wall. The invention further relates to a corresponding setting tool (50) and a setting method.