Borehole Thread Furrowing Tool for Low-Force Concrete Anchoring
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Solution Overview
Problem
Existing anchoring systems in mineral substrates, such as concrete, face challenges in achieving reliable high load-bearing capacity while maintaining easy and safe setting, particularly in cracked concrete where high pressures lead to 'plasticization' of the concrete matrix and irreversible deformation, and the friction between the anchor core and borehole wall increases screw-in forces.
Innovation Solution
A system comprising a furrowing tool with a cylindrical or conical base body and a furrowing thread that adapts the borehole wall to an imaginary cylinder, allowing for a larger core diameter anchor without excessive friction, and a two-part anchor design with a helix and threaded rod for enhanced load distribution and crack accommodation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the anchor core diameter is increased to improve load-bearing capacity, then the friction between the anchor core and borehole wall increases, resulting in higher screw-in forces
Solution Approach 1:
The invention divides the anchor into two separate parts: a helix (ground screw) and a threaded rod. The helix is responsible for engagement with the borehole wall and has an optimized core diameter for load-bearing, while the threaded rod provides the threading function. This segmentation allows the core diameter to be increased for higher strength without proportionally increasing friction during installation, as the threading is performed separately by a dedicated tool.
Solution Approach 2:
The invention uses a preliminary action by first creating the internal thread in the borehole using a specialized furrowing tool before inserting the anchor components. This pre-threading operation reduces the friction and resistance encountered during anchor installation, allowing for larger core diameters without excessive screw-in forces.
2Ease of operation
If a self-tapping thread is used to groove an internal thread in the borehole, then the setting process is simplified, but loose substrate particles are generated and the thread tip cuts into the substrate
Solution Approach 1:
The invention extracts the thread-grooving function from the anchor itself and performs it separately using a dedicated furrowing tool. This separation allows the anchor to be designed with an optimized core diameter for load-bearing without the compromise of self-tapping thread design, eliminating the generation of loose substrate particles and unwanted substrate cutting by the thread tip.
Solution Approach 2:
The invention introduces an intermediary tool (the furrowing tool with cutting edges) that performs the thread-grooving function. This intermediary device cleanly cuts the internal thread without generating loose particles or damaging the substrate, and the anchor components are then simply inserted into the pre-formed thread.
3Manufacturing precision
If the outside diameter of the cutting thread is made smaller than the outside diameter of the external thread, then the pre-cut internal thread is smaller, but the thread tip of the external thread still cuts into the substrate generating loose particles
Solution Approach 1:
The invention completely separates the thread-grooving operation from the anchor insertion operation. The furrowing tool with cutting edges creates a precise internal thread with exact dimensions, and the anchor is then inserted without any further thread cutting. This extraction eliminates the problem of thread tip cutting into the substrate regardless of diameter relationships.
4Reliability
If adhesive processes are used for reinforcement and lap joints, then reliable bonding is achieved, but the process becomes complex and requires specialist expertise
Solution Approach 1:
The invention replaces the chemical adhesive bonding system with a mechanical connection system. The helix with its optimized thread geometry creates a secure mechanical engagement with the borehole wall, and the threaded rod provides a reliable mechanical connection for reinforcement and lap joints. This mechanical system achieves comparable or superior reliability to adhesive bonding while being much simpler to install and not requiring specialist expertise.
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 system enables high load-bearing capacity with reduced screw-in forces and improved anchoring depth, allowing for efficient reinforcement and lap joints in concrete structures without the need for complex adhesive processes, and can be easily and quickly implemented with minimal specialist expertise.
Implementation Method 1
A plurality of elevations are formed on the outer surface of the base body, each of which has a cutting edge, with all of the cutting edges lying at least in sections on an imaginary cylinder... and with the cutting edges being suitable when screwing the furrowing tool into the borehole at least partially to remove the inner wall of the borehole
Data Source
Figure 1a~1b
Figure 1c~1e
Figure 2a~2b
AI summary
The invention relates to a system for securing an anchor (40) in a borehole in a mineral substrate, in particular concrete, mortar, or brickwork, comprising an anchor (40) with a core section and a threaded section (52) and comprising a furrowing tool (10) for furrowing an internal thread in the borehole, wherein the furrowing tool (10) comprises the following: a main part (12) with a leading end and a trailing end (12a, 12b), said main part (12) having an outer surface on which a furrowing thread (18) is formed that is suitable for furrowing the internal thread into the wall of the borehole. The outer surface of the main part (12) is equipped with a plurality of elevations (24), each of which has a cutting edge (26), and all of the cutting edges (26) lie at least partly on an imaginary cylinder with a diameter (do). The cutting edges (26) are suitable for at least partially removing the inner wall of the borehole when the furrowing tool (10) is rotated into the borehole in order to adapt the internal wall of the borehole to the imaginary cylinder.