Fastener Recess and Stabilizer Ribs for Stable High-Torque Driving
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Solution Overview
Problem
Existing threaded fastener drive systems face challenges with surface-to-surface engagement, often resulting in concentrated stresses and material failure due to misalignment, debris, and inconsistencies, leading to premature disengagement and damage.
Innovation Solution
The design of fasteners and drivers with a central core and radiating wings or lobes, featuring transition surfaces and grooves that provide a broader contact area and stabilizing features like torque pads and ribs, reducing stress concentrations and enhancing alignment stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If driver-recess engagement is concentrated in small areas or points due to misalignment or debris, then the driving load cannot be distributed over a broad surface area, but this results in concentrated stresses leading to material failure or plastic deformation
Solution Approach 1:
The recess is segmented into multiple wings (typically four) radiating from a central core, with each wing having sidewalls that engage corresponding lobes of the driver. This segmentation distributes the driving load across multiple contact points rather than concentrating it in a single area, reducing stress concentration while maintaining effective torque transmission.
Solution Approach 2:
The invention introduces transition surfaces that extend from the top of the recess to the bottom region, creating a three-dimensional engagement geometry. These transition surfaces provide additional contact areas between the driver and recess, transforming the engagement from a simple point or line contact to a multi-faceted surface interaction that distributes stress more effectively.
2Manufacturing precision
If the driver and fastener are slightly misaligned or the fastener varies from design specifications, then the area of contact between driver and fastener is substantially reduced, but this reduction in contact area increases the risk of material failure
Solution Approach 1:
The recess features asymmetric transition surfaces with specific angles and geometries that are optimized to accommodate minor variations in manufacturing tolerances. The wings and sidewalls are positioned and angled to ensure that even with slight misalignment or dimensional variations, the driver maintains adequate contact area across multiple surfaces rather than losing engagement entirely.
Solution Approach 2:
The transition surfaces are designed to guide the driver into proper alignment with the recess before full engagement occurs. The geometry of these surfaces provides a self-aligning mechanism that compensates for minor misalignments, ensuring that the driver and recess settle into optimal contact positions even when initial positioning is imperfect.
3Strength
If the recess deforms to define ramp-like surfaces inclined from the vertical under high torque, then the driver may cam-out of the recess, but this cam-out results in premature disengagement and potential damage to the work piece
Solution Approach 1:
The recess features localized geometric features including wings with specific sidewall angles and transition surfaces with controlled inclinations. These local geometric qualities are designed to resist deformation under torque while preventing cam-out. The sidewalls and transition surfaces are angled to maintain vertical alignment even when subjected to high loads, ensuring the recess maintains its structural integrity and engagement stability.
Data Source
AI summary
Fasteners, drivers, punches, fastener systems, and methods of making fasteners, drivers, punches, and fastener systems are disclosed herein. The fasteners may include a recess having a groove in an inner transition surface. Corresponding drivers may include one or more stabilizing ribs for interfacing with the groove in the fastener recces for providing stability.