Blind Fastener Anti-Rotation Structure for Variable Grip Thickness
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Solution Overview
Problem
Existing blind fasteners with integrated anti-rotation features often rely on a work piece or sleeve insert as a mechanical ground for preventing rotation, which limits flexibility and requires additional structures, whereas the new generation of blind fasteners need to accommodate varying work piece thicknesses and prevent rotation without external mechanical interference.
Innovation Solution
The proposed solution involves a collet body and cylinder body with sectional face portions forming a two-part anti-rotation mechanism, where the collet body and cylinder body are axially translatable but not rotatable, using internal slots and segments to prevent complete rotation, and an interface for a temporary anti-rotation tool, allowing for variable displacement and secure fastening without external mechanical interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a work piece or sleeve insert is used as a mechanical ground for anti-rotation, then rotation prevention is achieved, but device complexity increases and flexibility is limited
Solution Approach 1:
The patent combines the anti-rotation function directly into the collet body by integrating reactive surfaces onto the cylindrical surface of the collet body itself. This merging eliminates the need for separate mechanical grounds (work pieces or sleeve inserts) and integrates rotation prevention into the fastener's core structure, thereby reducing overall device complexity while maintaining reliability.
Solution Approach 2:
The collet body serves itself by providing its own mechanical ground through integrated reactive surfaces on its cylindrical surface. Instead of relying on external structures (work pieces or sleeve inserts) to prevent rotation, the collet body's own geometry and reactive surfaces create the anti-rotation mechanism, enhancing flexibility and reducing the need for additional components.
2Reliability
If a work piece or sleeve insert provides mechanical ground for anti-rotation, then rotation is prevented, but adaptability decreases due to requirements for additional structures
Solution Approach 1:
By merging the anti-rotation function into the collet body's own structure through integrated reactive surfaces, the invention eliminates dependencies on specific work piece geometries or additional sleeve inserts. This makes the fastener adaptable to varying work piece thicknesses and configurations, thereby enhancing versatility while maintaining reliable rotation prevention.
Solution Approach 2:
The collet body is designed with multi-functionality, serving both as the fastening element and as its own mechanical ground for anti-rotation. The reactive surfaces on the collet body's cylindrical surface enable it to prevent rotation universally across different work piece configurations without requiring specialized additional structures, thus improving adaptability.
3Device complexity
If reactive surfaces are integrated on the cylindrical surface of the collet body, then anti-rotation is achieved without external mechanical ground, but manufacturing precision requirements increase
Solution Approach 1:
The reactive surfaces on the collet body's cylindrical surface can be designed as segmented or discrete features rather than continuous complex geometries. This segmentation simplifies the manufacturing process by breaking down the precision requirements into manageable discrete elements, reducing overall manufacturing difficulty while maintaining the anti-rotation function.
Solution Approach 2:
The reactive surfaces are configured with asymmetric geometries that provide effective anti-rotation functionality with simpler manufacturing requirements. By strategically placing asymmetric reactive surface features on the collet body, the design achieves rotation prevention without requiring high-precision symmetric features, thereby reducing manufacturing precision demands.
Data Source
AI summary
Fasteners and related systems according to the invention include a collet body having a first part of a two part anti-rotation arrangement and a cylinder body having a second part of the two part anti-rotation arrangement wherein the collet body and the cylinder body are mateably axially translatable with respect to each other, and have the same or similar outer diameter in some embodiments or not in others. A threaded member rotationally engages the collet body and compressively contacts the cylinder body during operation of the fastener to creating a clamping effect. Rotational interference between the first and second parts of the anti-rotation arrangement preferably occurs at sectional face portions of at least the collet body. Resistance to induced rotation of the cylinder body relative to a work piece rotation of the threaded member is preferably provided by a tool engaging a tool interface present on the cylinder body.