Slotted Collar 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 slotted collars and tapered bores to create a shear joint, transforming a bolted joint into a riveted joint with fewer and lighter fasteners, allowing for strong and serviceable connections.
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 fastening system is divided into three distinct components: a bolt for serviceability, a tapered collar for strength, and a tapered bore for structural integration. This segmentation allows each component to fulfill its specific function while working together to resolve the contradiction between ease of operation and joint strength.
Solution Approach 2:
The tapered collar acts as an intermediary element between the bolt and the workpieces. It transforms the tensile force from the bolt into a shear force distribution across the tapered bore interface, enabling the joint to achieve rivet-like strength while maintaining bolt serviceability.
2Strength
If a riveted joint is used, then joint strength is improved, but serviceability deteriorates
Solution Approach 1:
By separating the fastening function (bolt) from the strengthening function (tapered collar and bore), the system achieves rivet-like strength without sacrificing serviceability. The bolt can be independently removed and replaced, while the tapered collar remains as a permanent strengthening element.
Solution Approach 2:
The tapered collar provides localized strength enhancement at the joint interface, while the bolt maintains its serviceability characteristics. Each component has optimized properties for its specific function, allowing the joint to exhibit both high strength and ease of service.
3Strength
If a greater number of bolts are used, then joint strength is improved, but device complexity and weight increase
Solution Approach 1:
The tapered collar serves as a force-distributing intermediary that allows a single bolt to effectively replace multiple bolts. By distributing the load across the tapered bore interface, the system achieves equivalent or superior strength with fewer fasteners, reducing complexity and weight.
Solution Approach 2:
The tapered geometry of the collar and bore creates a progressive force distribution that increases with insertion depth. This parameter change allows the joint to develop maximum strength with a single fastener, eliminating the need for multiple bolts to achieve adequate load distribution.
4Strength
If heavier bolts are used, then joint strength is improved, but device weight increases
Solution Approach 1:
The tapered collar acts as a mechanical advantage intermediary, allowing lighter bolts to generate equivalent joint strength. The tapered geometry amplifies the force from the lighter bolt through the collar, distributing it effectively across the joint interface without requiring heavier fasteners.
Solution Approach 2:
The tapered (curved) geometry of the collar and bore creates a progressive contact interface that distributes loads more efficiently than straight cylindrical interfaces. This curved geometry allows lighter fasteners to achieve the same joint strength by optimizing force distribution throughout the insertion depth.
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 the serviceability of bolts while achieving the strength of riveted joints.
Implementation Method 1
a bolt merely creates friction between the joined components to secure the joint
Implementation Method 2
slotted collars and tapered bores to create a shear joint
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A mechanical fastener assembly 14 is provided for joining two or more workpieces 10, 12. The assembly includes a mechanical fastener 42 and a slotted collar 26a, 26b. The mechanical fastener has a shaft 40 received within aligned bores 18a, 18b, 24a, 24b of the workpieces, while the slotted collar surrounds at least a portion of the shaft and is also received within the aligned bores. Inserting and advancing the slotted collar into the aligned bores causes the slot 28 of the slotted collar to at least partially close, thereby causing an inner surface of the slotted collar to engage at least a portion of the shaft of the mechanical fastener and an outer surface of the slotted collar to engage at least a portion of the aligned bores of the two workpieces. Such a mechanical fastener assembly can effectively transform a bolted joint into a stronger shear joint.