Attachment Bolt With Multi-Diameter Cavity For Wear Reduction
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Solution Overview
Problem
Existing fasteners in tensioned support systems, such as those used in aircraft access systems, face challenges in securely attaching tension members while minimizing wear and ensuring consistent tension, particularly due to the lack of effective designs that accommodate varying diameters and reduce edge stress.
Innovation Solution
The design of an attachment bolt with a head and shaft portion featuring a cavity with a linearly extruded segment and an enlarged diameter at the tip, allowing a tension member to pass through and incorporating a terminal element seated in the enlarged diameter, which reduces wear and maintains tension by using complementary threads with a receiving component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional fastener design is used, then the structure is simple and easy to manufacture, but the wear resistance is poor and tension consistency cannot be maintained
Solution Approach 1:
The cavity incorporates segments with different diameters (reduced diameter segment, linearly extruded segment, and enlarged diameter segment) to provide different functions at different locations. The reduced diameter segment minimizes wear on the tension member, while the enlarged diameter segment accommodates the terminal element, and the linearly extruded segment maintains consistent tension.
2Reliability
If a fastener with varying diameter cavity is used, then wear is reduced and tension is maintained, but the manufacturing precision requirements increase
Solution Approach 1:
The cavity is pre-formed with specific diameter variations during manufacturing, including the reduced diameter segment, linearly extruded segment, and enlarged diameter segment. This preliminary structuring ensures that when the tension member is installed, the wear-minimizing and tension-maintaining functions are automatically activated without requiring additional adjustment or precision during assembly.
3Reliability
If a rounded head portion is used, then edge stress is reduced and tension consistency is improved, but the manufacturing complexity increases
Solution Approach 1:
The head portion is designed with a rounded geometry and specific dimensional parameters (such as the relationship between the enlarged diameter segment and the head portion) that optimize stress distribution. By carefully selecting and controlling these geometric parameters, the design achieves reduced edge stress and improved tension consistency while maintaining manufacturability through standard forming processes.
Data Source
AI summary
Attachment bolts and tensioned support systems (e.g., aircraft access systems) are set forth herein. According to one embodiment, an attachment bolt for use in a tensioned support system includes a head portion and a shaft portion extending from the head portion. The head portion has an end face, and the shaft portion has at least one thread and a tip distal to the head portion. A cavity extends entirely through the head and shaft portions and has a linearly extruded segment, an extended diameter at the end face, and an enlarged diameter at the tip. The extended diameter is larger than a diameter of the linearly extruded segment, and the enlarged diameter is larger than the diameter of the linearly extruded segment.