Reusable Pin Clamp Radial Bead for Composite Preassembly
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Solution Overview
Problem
Existing temporary fastening devices for preassembling composite structural members, such as those in aircraft, cause delamination due to high local contact pressure and sharp edges, which can damage the materials.
Innovation Solution
A reusable pin clamp with a deformable tubular end piece that forms a radial bead at a distance from the structural members, reducing contact pressure and eliminating sharp edges, while maintaining access from a single side and allowing for easy removal and replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If retractable spoilers with sharp edges are used in traditional pin clamps, then the clamping force and preload stress are improved, but the composite material suffers delamination and mechanical strength deterioration
Solution Approach 1:
The device separates the clamping function (spoiler) from the bearing surface (anvil). The spoiler provides clamping force while the anvil provides a large bearing surface, dividing the harmful contact pressure function from the useful clamping function.
Solution Approach 2:
The anvil acts as an intermediary element between the spoiler and the composite material. It transfers the clamping force from the spoiler to the composite material while distributing the pressure over a large surface area, preventing direct contact between the sharp spoiler edges and the composite material.
2Ease of operation
If access from both sides of the structure is required for traditional pin clamps, then the installation and removal processes are simplified, but the ease of operation is reduced when single-side access is needed
Solution Approach 1:
The device inverts the traditional approach by having the operational elements (anvil and bearing surface) located on the same side as the access point, while the fastening elements (spoiler) extend to the opposite side. This allows installation and removal from a single side while maintaining effective clamping.
3Ease of manufacture
If the end piece is made consumable and replaceable, then the cost of reuse is reduced, but the device complexity increases due to the modular design
Solution Approach 1:
The device is segmented into a permanent body and a consumable end piece that can be independently replaced. This allows the expensive permanent components to be reused while only the cheaper end piece needs replacement, reducing overall costs despite the modular complexity.
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 effectively reduces local contact pressure, prevents delamination, and allows for cost-effective reuse of the pin clamp by replacing the consumable end piece, ensuring minimal damage to composite materials during assembly and disassembly.
Implementation Method 1
locally axially compacted under the action of a force applied on said pulling rod in order to form a radial bead
Data Source
AI summary
A fastening device for preassembling structural members includes a hollow cylindrical body; a bearing ring provided at a proximal end of the hollow body and against which one of the structural members is intended to bear in a fastening position; a pulling threaded rod extending through the hollow body to be inserted into the structural members; a tightening means connected to the pulling threaded rod for maintaining the structural members against each other, the tightening means including a removable tubular end piece for mounting on a proximal threaded end of the pulling threaded rod that can be locally axially compacted under the action of a force applied on the pulling threaded rod in order to form a radial bead for sandwiching the structural members between the latter and the bearing ring; the fastening device including a sheath.