Borehole Threading Tool for Low-Torque Concrete Anchoring
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Solution Overview
Problem
Existing anchoring technologies in mineral substrates, such as concrete, face challenges in achieving high load-bearing capacity while maintaining low screwing torques and preventing anchor failure due to the irregular shape of boreholes and the deformation of concrete under load.
Innovation Solution
A system comprising a grooving tool with a cylindrical or conical base body and cutting edges that adapt the borehole to a cylindrical shape, allowing for a larger anchor core diameter with reduced friction and increased load-bearing capacity, and a two-part anchor design with a spiral coil and threaded rod for enhanced flexibility and load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional self-tapping screw anchor is used to groove an internal thread directly into the mineral substrate, then the anchoring process is simplified, but the screwing torque becomes excessively high and the load-bearing capacity is reduced due to concrete deformation and irregular borehole shape
Solution Approach 1:
The anchoring system is divided into two separate components: a grooving tool that first creates a pre-formed internal thread in the borehole, and a screw anchor that then threads into this pre-formed thread. This segmentation allows the threading and anchoring functions to be separated, reducing the screwing torque required while maintaining ease of operation.
Solution Approach 2:
The grooving tool performs a preliminary action by creating a pre-formed internal thread in the borehole before the screw anchor is installed. This preliminary threading action prepares the borehole to receive the screw anchor with significantly reduced screwing torque, while the irregular shape of the borehole is maintained to ensure high load-bearing capacity through friction.
2Strength
If the borehole is drilled with a hammer drill creating an irregular shape, then the friction and load-bearing capacity are increased, but the screwing torque becomes excessively high due to poor thread engagement
Solution Approach 1:
The system separates the functions of thread formation and anchoring. The grooving tool with its cylindrical body creates a regular pre-formed internal thread that ensures low screwing torque, while the irregular borehole shape is preserved to provide high friction and load-bearing capacity. This segmentation resolves the contradiction between regular thread geometry (low torque) and irregular borehole shape (high strength).
Solution Approach 2:
Different geometric qualities are applied to different parts of the anchoring system: the grooving tool has a cylindrical, regular geometry to produce a uniform pre-formed thread for low screwing torque, while the borehole maintains its irregular shape from hammer drilling to ensure high friction and load-bearing capacity. Each local geometry is optimized for its specific function.
3Reliability
If the outer diameter of the cutting thread is made smaller than the external thread (creating an undersize), then the screwing resistance and solid setting feeling are increased, but the load-bearing capacity is reduced due to larger gap between anchor and borehole wall
Solution Approach 1:
The grooving tool performs a preliminary action by creating a pre-formed internal thread that matches the external thread of the screw anchor. This eliminates the need for an undersize pre-cut thread, allowing the anchor to fit tightly against the borehole wall throughout its length, maximizing friction and load-bearing capacity while still providing adequate screwing resistance through the thread engagement.
Solution Approach 2:
The grooving tool has a cylindrical base body that creates a pre-formed internal thread with consistent diameter along its length. This cylindrical geometry ensures uniform contact between the screw anchor and borehole wall, maximizing the friction-based load-bearing capacity while maintaining adequate thread engagement for screwing resistance.
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 reliable high-load anchoring with reduced screwing torques and improved load distribution, effectively preventing anchor failure by minimizing the gap between the anchor and the borehole wall and accommodating crack formation in the substrate.
Implementation Method 1
A plurality of elevations is formed on the outer surface of the base body, each having a cutting edge, wherein all cutting edges at least in sections lie on an imaginary cylinder... and the cutting edges are suitable to at least partially remove the inner wall of the borehole when screwing the grooving tool into the borehole
Data Source
AI summary
The invention relates to a system for securing an anchor in a borehole in a mineral substrate, in particular concrete, mortar, or brickwork, comprising an anchor with a core section and a threaded section and comprising a furrowing tool for furrowing an internal thread in the borehole, wherein the furrowing tool comprises the following: a main part with a leading end and a trailing end, said main part having an outer surface on which a furrowing thread is formed that is suitable for furrowing the internal thread into the wall of the borehole. The outer surface of the main part is equipped with a plurality of elevations, each of which has a cutting edge, and all of the cutting edges lie at least partly on an imaginary cylinder with a diameter (do). The cutting edges are suitable for at least partially removing the inner wall of the borehole when the furrowing tool is rotated into the borehole in order to adapt the internal wall of the borehole to the imaginary cylinder.