Double-Threaded Standoff Fastener for Rotation-Stable Installation
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Solution Overview
Problem
Existing standoff fasteners for compound floor structures face issues with unwanted rotation during installation due to the location of the head portion, leading to inefficiencies and increased costs, as well as limitations in diameter, which restrict the strength and economic feasibility of the composite floor structure.
Innovation Solution
A standoff fastener design with a head portion positioned between the screw and standoff portions, featuring a key shape for torque transmission and a larger anchor nut diameter, allowing for improved control and installation speed while increasing the diameter without excessive cost, by placing the head portion internally and using a longer standoff portion with threads for enhanced grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the head portion is located on the end of the fastener to accept torque, then torque transmission is enabled, but the fastener rotates out of alignment during installation
Solution Approach 1:
The head portion is inverted from the conventional end-location to an intermediate position between the screw portion and standoff portion. This inversion allows the drive axis to pass through the center of the head, eliminating the lever arm effect that caused rotation, while still enabling torque transmission through the key shape interface with the driver.
2Strength
If the diameter of the fastener is increased to improve strength, then the structural strength increases, but the cost increases significantly
Solution Approach 1:
The fastener is segmented into three functional portions: a screw portion for engagement with the subfloor, a head portion for torque transmission, and a standoff portion with extended length and threads for concrete anchoring. This segmentation allows optimization of each portion independently, enabling increased effective diameter and length for strength without proportionally increasing overall material cost.
Solution Approach 2:
The standoff portion extends the functional diameter and length in the axial dimension rather than requiring a larger radial diameter. By making the standoff portion longer than the screw portion and adding threads along its length, the fastener achieves increased structural strength and concrete grip without the cubic cost increase associated with larger diameter solid fasteners.
3Reliability
If the head portion is positioned internally between screw and standoff portions, then rotation control improves, but the device complexity increases
Solution Approach 1:
The head portion is merged with both the screw portion and standoff portion in an integral, monolithic structure. This merging eliminates the need for separate components, joints, or assembly steps, thereby reducing manufacturing complexity while achieving the reliability benefit of improved rotation control through the optimized head positioning.
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 design enhances the installation efficiency and cost-effectiveness by minimizing unwanted rotation and allowing for a larger diameter standoff fastener, thereby increasing the strength and stability of the composite floor structure.
Implementation Method 1
the head portion having a key shape which is selected from a group consisting of lobular, splinular, and polygonal; the key shape capable of accepting torque from a driver oriented on drive axis of the fastener
Implementation Method 2
the standoff portion having a threaded segment, where a diameter of the standoff portion is less than or equal to a diameter of the head portion
Implementation Method 3
a thread-forming portion having lobes adapted to enable formation of threads into a metal structure
Implementation Method 4
the screw portion including a fluted lead end
Data Source
AI summary
Presently disclosed is a standoff fastener for use in a compound floor structure. The threaded fastener includes a threaded standoff portion designed to accept a nut which has a diameter larger than a head portion of the standoff fastener. The head portion is located centrally within the fastener in order to reduce a tendency of the fastener to pivot within a driver during the fastening process.