Slotted Insert Bolted Joint for Rivet-Like Shear Strength
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Solution Overview
Problem
Bolted joints lack the strength of riveted joints while rivets are not serviceable, necessitating a mechanical fastener that combines the serviceability of bolts with the strength of rivets.
Innovation Solution
A mechanical fastener assembly using a slotted collar and retaining sleeve that transforms a bolted joint into a riveted joint by creating a shear connection, allowing for secure alignment and contact between the fastener and aligned bores, thereby enhancing joint strength without compromising serviceability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a bolted joint is used, then serviceability is improved, but joint strength deteriorates
Solution Approach 1:
The fastener system is divided into separate components: a bolt that can be removed for serviceability and a deformable collar that remains in the workpiece. The collar is segmented with slots that allow it to deform and create interference fit, while the bolt provides reversible fastening capability.
Solution Approach 2:
The deformable collar acts as an intermediary between the bolt and the workpiece. It transforms the simple friction-based bolted joint into a composite connection where the collar creates shear-based riveted joint strength through interference fit, while the bolt maintains serviceability.
2Strength
If a riveted joint is used, then joint strength is improved, but serviceability deteriorates
Solution Approach 1:
The system separates the permanent strength-providing component (collar in interference fit) from the removable serviceable component (bolt). The collar remains deformed in the workpiece to provide rivet-like strength, while the bolt can be independently removed for maintenance.
Solution Approach 2:
Instead of making the entire fastener permanent like a rivet, the invention inverts the approach by making only the strength-providing collar permanent through deformation, while keeping the fastening element (bolt) removable. This reverses the traditional rivet design where the entire fastener is permanent.
3Strength
If multiple bolts are used to achieve rivet-like strength, then joint strength is improved, but fastener quantity and weight increase
Solution Approach 1:
The single collar is segmented with slots that allow it to deform and create interference fit with the workpiece bore. This segmentation enables one collar to provide the shear strength that would otherwise require multiple bolts, reducing the total number of fasteners needed.
Solution Approach 2:
The collar's physical parameters change during installation - it transitions from a loose-fitting state to an interference fit state through deformation. This parameter change (from elastic to plastic deformation) creates the permanent, strength-providing connection that reduces the need for multiple fasteners.
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 solution provides a strong and serviceable joint using fewer and lighter fasteners than traditional bolted joints, maintaining flexibility for various applications and tolerances.
Implementation Method 1
the deformable collar is configured to elastically deform as the collar is pressed into the bore
Implementation Method 2
the deformable collar is configured to plastically deform to the final configuration
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A mechanical fastener assembly 400 is provided for joining two or more workpieces 10, 12. The assembly includes a mechanical fastener 42 and a slotted insert 402. The mechanical fastener has a shaft 40 received within aligned bores 18a, 18b, 24a, 24b of the workpieces. The slotted insert surrounds at least a portion of the shaft and has a body portion 404 received within the aligned bores, while an enlarged head portion 406 of the slotted insert is positioned outside of the bores.