Thread-Cutting Anchor Assembly for Low-Friction Concrete Fastening
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Solution Overview
Problem
Existing anchoring technologies in mineral substrates, such as concrete, face challenges in achieving reliable and 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 the gap between the anchor core and borehole wall is not optimally supported.
Innovation Solution
A system comprising a grooving tool with a cylindrical or conical base body and cutting edges that adapt the borehole shape to a cylindrical form, 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 load distribution and crack resistance.
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, making screwing more difficult
Solution Approach 1:
The borehole is pre-adapted to a cylindrical shape using cutting edges on the grooving tool before the anchor is inserted. This preliminary action removes irregularities and reduces friction, enabling easier screwing of anchors with larger core diameters that provide higher load-bearing capacity
Solution Approach 2:
The shape parameter of the borehole is changed from an irregular hammer-drilled shape to a cylindrical shape through the cutting edges. This parameter change reduces the friction coefficient between the anchor core and borehole wall, allowing for larger core diameters without increasing screwing resistance
2Device complexity
If a monolithic anchor design is used, then the structure is simple, but the load distribution is less effective and crack resistance is reduced
Solution Approach 1:
The anchor is divided into two separate parts: a grooving tool for creating the internal thread and an anchor element for fastening. This segmentation allows each component to be optimized for its specific function, with the anchor element designed specifically for optimal load distribution and crack resistance without the constraints of integrating the grooving function
3Reliability
If the outer diameter of the cutting thread is made smaller than the external thread (undersize grooving), then loose substrate particles are produced to ensure compression, but screwing resistance increases and setting becomes more difficult
Solution Approach 1:
The diameter parameter of the cutting thread is changed to match the external thread diameter exactly (eliminating the undersize). This parameter change prevents excessive screwing resistance while still ensuring proper compression through the adapted cylindrical borehole shape, resolving the contradiction between reliability and ease of operation
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 secure anchoring with increased load-bearing capacity and reduced screwing forces, allowing for longer anchor lengths and easier installation, while maintaining low friction and supporting the concrete matrix effectively, even in cracked conditions.
Implementation Method 1
A plurality of elevations are formed on the outer surface of the base body of the grooving tool, each having a cutting edge, wherein all cutting edges at least in sections lie on an imaginary cylinder having a diameter do, 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, said furrowing tool comprising the following: a main part with a leading end and a trailing end, wherein a force is applied via which a torque can be transmitted to the main part in order to rotate the furrowing tool (10) into the borehole and furrow the thread, and the main part has an outer surface equipped with a furrowing thread which is suitable for furrowing the internal thread into the wall of the borehole. The furrowing tool has a drive element on the leading end of the furrowing tool, said drive element being suitable for interacting with an application of force to the anchor or a part thereof which is to be screwed into the borehole machined by the furrowing tool.