Lightweight Fastener Head With Self-Aligning Torque Transfer
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Solution Overview
Problem
Existing fasteners with hexagonal heads require excessive raw material for torque transmission, leading to weight and cost inefficiencies, and suffer from stripping issues due to poor alignment and surface contact during tightening and loosening, compromising safety and efficiency.
Innovation Solution
A lightweight fastener design with a unique head shape featuring radially extending support elements and grooves, and a corresponding drive apparatus with inclined slots and protrusions, ensuring effective torque transfer and self-alignment to prevent stripping and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a hexagonal head shape is used for torque transmission, then the fastener can be tightened and loosened with standard drive apparatus, but excessive raw material is required leading to increased weight
Solution Approach 1:
The head is segmented into multiple functional zones: a drive engagement zone with hexagonal or polygonal contact surfaces for torque transmission, and a reduced-weight zone where material is removed from areas not required for driving. This segmentation allows the head to maintain compatibility with standard drive apparatus while minimizing material usage and weight.
Solution Approach 2:
Different regions of the head have different material densities and structural properties. The drive engagement zones retain full material density and hexagonal geometry for proper tool contact, while other regions use reduced material or hollow structures. This local quality variation maintains driving compatibility while reducing overall weight.
2Weight of moving object
If weight reduction is achieved by removing material from the head, then fastener weight decreases, but stripping issues occur due to poor alignment and surface contact
Solution Approach 1:
The head geometry is designed with self-aligning features such as inclined surfaces and guide edges that automatically orient the fastener correctly as the drive apparatus approaches. This preliminary alignment action occurs before torque application, ensuring proper contact between the drive tool and the head's drive zones, thereby preventing stripping even with reduced material.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of a drive apparatus with specifically designed contact surfaces that match the head's geometry. This intermediary ensures uniform torque distribution across the head's drive zones, preventing stress concentration and stripping while working with the reduced-material head design.
3Loss of substance
If material is removed from the head to reduce weight, then processing cost decreases, but the contact area for torque transmission is reduced
Solution Approach 1:
The patent utilizes three-dimensional head geometries with inclined surfaces, recesses, and protrusions that increase the effective contact area for torque transmission without increasing the horizontal footprint or material volume. By exploiting the vertical and angular dimensions, the design maintains adequate contact area while minimizing material consumption.
Solution Approach 2:
The head employs composite structural designs combining different material properties in different zones - harder materials or surface treatments in the drive engagement areas for wear resistance and torque transmission, and lighter materials in non-critical zones. This composite approach maintains functional contact area while reducing overall material consumption.
Data Source
AI summary
A lightweight fastener is designed for use in a variety of industries, especially in the automotive industry, such as construction, machine manufacturing, building and railway, and a drive apparatus compatible with said fastener that applies the torque required for its tightening and loosening is provided.