Threaded Drill Screw Setting in Concrete With Rebar Contact
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Solution Overview
Problem
Screws in mineral materials, particularly high-strength concrete, often experience undesired blocking and increased wear due to rebar contact, leading to performance losses or complete thread destruction, especially when using screws with cutters in the thread course.
Innovation Solution
A method involving a threaded drill that precuts a pilot thread with a smaller external diameter than the screw thread, allowing for easy insertion and compression of substrate particles to stabilize the hole, ensuring reliable and high load-bearing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a screw with cutters in the thread course is used to set a screw in mineral material, then the screw can be introduced into the drilled hole, but blocking occurs due to rebar contact and increased wear on the cutters and thread recesses
Solution Approach 1:
The patent applies preliminary action by precutting the internal thread in the substrate before introducing the screw. The threaded drill creates the thread form in advance, eliminating the need for cutters on the screw to engage with the substrate during insertion. This prevents blocking and wear issues while ensuring reliable screw setting.
2Reliability
If the external diameter of the cutting thread is made smaller than the external diameter of the screw thread, then substrate particles are compressed to stabilize the hole, but the threaded drill requires higher precision manufacturing
Solution Approach 1:
The patent applies parameter changes by specifying that the external diameter of the cutting thread is smaller than the external diameter of the screw thread. This dimensional parameter change allows substrate particles to be compressed during screw insertion, stabilizing the hole and improving reliability. The precision requirement is managed through defined diameter relationships rather than absolute tolerances.
3Reliability
If a threaded drill is used to precut the internal thread, then blocking and wear are prevented, but the device complexity increases due to additional tools required
Solution Approach 1:
The patent merges the drilling and threading operations into a single threaded drill tool. The threaded drill combines drilling capability with internal thread cutting in one device, eliminating the need for separate drills and thread inserts. This reduces overall device complexity while maintaining the reliability benefits of precut threads.
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
This method provides reliable screw setting with minimal effort, achieving high load values and improved corrosion resistance by preventing blocking and wear, especially in rebar contact scenarios.
Implementation Method 1
an internal thread is produced in the drilled hole by means of a threaded drill provided with a cutting thread
Implementation Method 2
the screw is introduced, particularly screwed, into the drilled hole and in so doing the external thread of the screw is screwed into the internal thread, produced by the threaded drill
Data Source
AI summary
A method for setting a screw, which has an external thread in a front region and a drive in a rear region for introducing a torque into the screw, in a drilled hole in a substrate of a mineral material includes producing an internal thread in the drilled hole by a threaded drill provided with a cutting thread and then introducing the screw into the drilled hole and in so doing the external thread of the screw is screwed into the internal thread, produced by the threaded drill, in the drilled hole. The external diameter of the cutting thread of the threaded drill is smaller than the external diameter of the external thread of the screw.