Notched Concrete Screw Threads for Low-Torque Hurricane Anchoring
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Solution Overview
Problem
Existing screw configurations for concrete applications require high torque for installation and lack sufficient resistance to pull-out, especially in hurricane forces, which complicates quick and effective installation and durability.
Innovation Solution
A screw design featuring a high thread with notches and a low thread without notches, both with specific angles and lengths, providing a unique thread profile that reduces installation torque and enhances pull-out resistance, suitable for concrete and hurricane applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional screw configurations are used for concrete applications, then installation is straightforward, but high torque is required and pull-out resistance is insufficient
Solution Approach 1:
The screw thread is segmented into two distinct types: a high thread with notches and a low thread without notches. This segmentation allows each thread type to perform different functions - the high thread provides enhanced pull-out resistance through notch engagement with concrete, while the low thread facilitates easier installation with reduced torque requirements.
Solution Approach 2:
Different regions of the screw thread are given different properties. The high thread portion features notches that engage with concrete to maximize pull-out resistance, while the low thread portion maintains a smooth profile for easier installation. This local differentiation of thread properties resolves the contradiction between installation ease and holding strength.
2Ease of operation
If high torque is applied during installation, then screw penetration is achieved, but installer effort and energy consumption increase
Solution Approach 1:
The threaded shank is divided into low thread and high thread sections, where the low thread section enables initial penetration with minimal torque and energy input, while the high thread section engages later to provide secure anchoring without requiring excessive installation energy.
Solution Approach 2:
The thread geometry parameters are changed along the length of the shank - the low thread has optimized parameters for low-friction installation, while the high thread has parameters optimized for high-strength anchoring. This parameter variation along the screw length reduces overall installation energy requirements.
Data Source
AI summary
A screw for use concrete and hurricane applications includes a head end, a shank and a tapered end. A high thread begins on the tapered end, extends onto the shank and terminates at a first axial location along the shank, wherein the high thread defines a high peripheral edge, and at least a first helical portion of the high peripheral edge includes a plurality of notches and the first helical portion extends from on or proximate to the tapered end and substantially to the first axial location. A low thread begins on the tapered end, extends onto the shank and terminates substantially at the first axial location such that an axial length of the low thread is substantially the same as and contiguous with an axial length of the high thread. The low thread defines a low peripheral edge that is free of any notches.