Concrete Screw Support Thread for Low-Torque Anchoring
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Solution Overview
Problem
Conventional concrete screws face high resistance during screwing, leading to potential failure due to excessive screw-in depth, and existing solutions do not efficiently balance screw load with minimal screw-in depth.
Innovation Solution
A screw design featuring a support element integrated with the core, which includes a support thread that thickens the cutting thread flanks along the central longitudinal axis, reducing the core diameter and creating an enlarged annular gap for drilling dust, allowing stable and error-free screwing with reduced material costs and increased cutting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the screw-in depth is increased to achieve higher anchoring load, then the anchoring strength is improved, but the screwing resistance increases excessively causing potential screw failure
Solution Approach 1:
The screw is segmented into functionally distinct zones: a cutting thread section for material removal and thread groove formation, and a support thread section for anchoring. This segmentation allows the cutting section to create space while the support section provides holding power, reducing the need for excessive screw-in depth to achieve adequate anchoring.
Solution Approach 2:
Different sections of the screw have different local properties: the cutting thread has sharper, more aggressive flanks for material removal, while the support thread has optimized flank angles for load distribution. This local quality differentiation enables effective anchoring with reduced screw-in depth by optimizing each section's function rather than using a uniform design throughout.
2Weight of stationary object
If the core diameter is reduced to minimize material usage and cost, then the material cost is decreased, but the structural strength and stability during screwing may be compromised
Solution Approach 1:
The cutting thread performs preliminary action by removing material and creating thread grooves in the concrete before the support thread engages for anchoring. This preliminary material removal creates space that reduces interference with the core, allowing a smaller core diameter to be used without compromising overall screwing stability.
Solution Approach 2:
The support element acts as an intermediary between the small-diameter core and the borehole wall. It provides the necessary structural support and stability during screwing while allowing the core to maintain a reduced diameter for material efficiency, effectively mediating between the conflicting requirements of core size and stability.
3Strength
If the contact surface between thread flanks and concrete is increased to improve anchoring, then the anchoring load capacity is improved, but the scraping effect on concrete increases reducing suitability for cracked materials
Solution Approach 1:
The support thread features locally optimized flank angles that differ from conventional designs. These specific angle configurations concentrate the anchoring function at discrete contact points rather than along extended surface areas, providing sufficient load capacity while minimizing the scraping effect on surrounding concrete, particularly important for cracked or fragile substrates.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A screw (5) is used for screwing into a borehole (3) in a material (2). The screw (5) comprises a substantially cylindrical core (6) with a central longitudinal axis (7) and with a core diameter (DK), a cutting thread (9) formed integrally with the core (6), extending along a cutting thread section (ASG) and having a cutting thread outer diameter (DSG) for screwing into the material (2), and a support element (16) formed integrally with the core (6) for supporting the screw (5) in the borehole (3).