Blind Bolt Shear Sleeve Assembly for Inaccessible Joint Interfaces
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Solution Overview
Problem
Blind bolts face challenges in applications where shear resistance is required, as existing configurations may not provide sufficient stability and adaptability to varying shear forces, especially when the distal end of the hole is inaccessible.
Innovation Solution
A blind bolt design featuring a shaft with an expandable anchor and a collapsible cylinder that positions a shear sleeve across the interface between two members, utilizing a malleable material with controlled deformation patterns to enhance shear resistance, allowing the shear sleeve to be effectively positioned and secured through a nut tightening mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring is used to position the shear sleeve, then the shear sleeve can be held in position, but the device complexity increases and adaptability to varying shear forces is limited
Solution Approach 1:
The patent removes the spring component from the assembly and replaces it with a collapsible cylinder made of malleable material. This extraction of the spring eliminates the complexity associated with spring mechanisms while maintaining the ability to position the shear sleeve through the collapsible cylinder's deformation under nut tightening force.
Solution Approach 2:
The patent changes the material parameter of the positioning component from elastic (spring) to malleable (collapsible cylinder). The malleable material allows the cylinder to deform permanently under force, providing a stable positioning mechanism without the ongoing elastic forces and complexity of a spring system.
2Strength
If the shear sleeve is positioned to cross the interface, then shear resistance is improved, but the device complexity increases due to additional positioning mechanisms
Solution Approach 1:
The collapsible cylinder serves dual functions: it positions the shear sleeve across the interface and simultaneously collapses under nut tightening to secure the entire assembly. This self-service mechanism eliminates the need for separate positioning mechanisms, reducing device complexity while maintaining shear resistance.
Solution Approach 2:
The patent merges the positioning function and the securing function into a single integrated mechanism. The collapsible cylinder both positions the shear sleeve and, when collapsed by the nut, secures the entire assembly, combining multiple functions into one component to reduce overall device complexity.
3Stability of the object's composition
If a rigid positioning mechanism is used, then the shear sleeve position is stable, but adaptability to varying shear forces and hole configurations is reduced
Solution Approach 1:
The patent transitions from a static rigid positioning mechanism to a dynamic collapsible cylinder. The cylinder can deform and adapt its shape during installation, then stabilize in its collapsed state. This dynamic behavior allows adaptation to varying shear forces and hole configurations while maintaining position stability once installed.
Solution Approach 2:
The malleable material of the collapsible cylinder allows it to change its physical state from undeformed to collapsed under applied force. This parameter change enables the mechanism to adapt to different installation conditions and shear force requirements while providing stable positioning once the collapse is complete.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design provides enhanced shear resistance and stability by ensuring the shear sleeve is properly positioned and secured across the interface, effectively resisting shear forces and maintaining the blind bolt's position within the hole, even in applications where the distal end is inaccessible.
Implementation Method 1
the collapsible cylinder is deformed in a desired pattern by the force of the tightening nut
Implementation Method 2
The collapsible cylinder is made of a malleable material... controlled deformation in response to a force parallel with it's axis
Implementation Method 3
the inner sleeve is configured to friction fit within the outer sleeve such that the friction between the outer and inner sleeves will resist sliding, but will allow sliding
Data Source
AI summary
A blind bolt extends through a hole which extends through a first and second member. An anchor is disposed on the distal end of a blind bolt shaft, and the anchor has expanded and contracted configurations. An anchor is disposed on the distal end on a shaft and is positioned beyond the distal end of the hole engaging a surface of the second member thereby holding the shaft in the hole. A shear sleeve is disposed on the blind bolt proximate to the distal end of the shaft and has a length sufficient to extend across the second member, across the interface between the first and second members and partially across the first member. A nut is threaded on the threads of the shaft, and a collapsible cylinder is disposed on the blind bolt shaft between the sheer sleeve and nut. The collapsible cylinder and the sheer sleeve have a combined length such that when the anchor is in the expanded configuration and the sheer sleeve and the collapsible cylinder are positioned on the shaft within the hole, the collapsible cylinder pushes the sheer sleeve to a position extending across the interface between the first and second members as the nut is tightened on the shaft. The collapsible cylinder may be a deformable crushable sleeve or a telescoping sleeve.