Dual-Zone Fastener Socket and Driver Bit for Cam-Out Reduction
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Solution Overview
Problem
Existing fasteners and drivers experience premature cam-out and breakage due to poor fit caused by anti-corrosive coatings and localized stress concentrations, which reduce surface contact and increase the risk of deformation.
Innovation Solution
A fastener design featuring a dual zone socket area with an upper inwardly tapering section and a lower vertical section, along with a corresponding driver bit, providing enhanced engagement through asymmetrical driving and removal surfaces, allowing for increased surface contact and torque distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anti-corrosive coatings are applied to the fastener, then corrosion resistance is improved, but surface contact area is reduced
Solution Approach 1:
The socket is designed with two distinct zones: an upper zone with a larger diameter that accommodates the coating thickness and provides initial driver engagement, and a lower zone with a smaller diameter that provides the primary torque transmission surface. This local differentiation allows the coating to be present throughout while maintaining adequate contact area in the lower zone.
Solution Approach 2:
The socket is segmented into multiple functional zones along its depth: an upper engagement zone for driver insertion and alignment, and a lower torque transmission zone for force application. This segmentation allows each zone to optimize for its specific function while accounting for the presence of anti-corrosive coatings.
2Area of stationary object
If the driver and recess are designed to fit closely for maximum face-to-face contact, then surface contact is improved, but clearance for insertion is reduced
Solution Approach 1:
The socket is divided into an upper zone with a larger diameter that provides clearance for driver insertion and alignment, and a lower zone with a smaller diameter that provides maximum surface contact for torque transmission. This segmentation resolves the contradiction by providing both insertion clearance and contact area in different spatial zones.
Solution Approach 2:
The solution moves the clearance requirement from the radial dimension (where it would reduce contact area) to the axial dimension (socket depth). The upper zone extends axially to provide insertion clearance, while the lower zone maintains radial tightness for maximum contact area.
3Force
If torque is applied through localized stress regions, then force transmission is achieved, but deformation and breakage risk increase
Solution Approach 1:
The lower zone of the socket is designed with optimized geometry and surface properties to concentrate and distribute torque forces evenly across the driver-fastener interface. This local optimization of the torque transmission zone reduces stress concentrations that would otherwise lead to deformation or breakage.
Data Source
AI summary
Methods and apparatus for a fastener head having a dual zone socket area and a mating driver bit according to aspects of the present technology include a fastener configured with driving surfaces adapted to provide enhanced engagement between each other during use. The fastener includes a recessed socket area with a sidewall that has an upper inwardly tapering section and a lower vertical section that extends to the bottom of the recessed socket area. The upper inwardly tapering section of the sidewall may also include an offset relative to the lower vertical section to create asymmetrical driving and removal surfaces. The technology also includes a corresponding mating driver bit configured with mating surfaces to the fastener to provide enhanced engagement between the fastener and mating driver bit. The technology also allows either the fastener or the driving bit to be used with preexisting fasteners and driver bits.