Blind Rivet Assembly with Pull-Through Mandrel for Flush Installation
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Solution Overview
Problem
Conventional blind rivet assemblies protrude beyond workpiece surfaces, leading to space inefficiency, interference, and potential damage during assembly, and require breakable mandrel heads that can cause rattling and shortening of electrical circuits.
Innovation Solution
A blind rivet assembly where the mandrel head is completely pulled through the rivet without severing, utilizing a mandrel with ribs on an outwardly tapering shoulder, allowing for flush or below flush installation and reducing setting loads, thus eliminating the need for broken mandrel heads and enhancing assembly quality and tool longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional blind rivet assemblies with protruding ends are used, then the rivet structure is simple and easy to manufacture, but the packaging space is wasted and the rivet heads are prone to interference or damage during assembly
Solution Approach 1:
Instead of having the mandrel head break and remain in the rivet body (conventional approach), this invention inverts the approach by designing the mandrel head to be pulled completely through the rivet body without breaking. The mandrel head emerges from the far end of the rivet, achieving flush or below-flush installation that eliminates protruding ends and their associated problems with space waste and interference.
2Reliability
If breakable mandrel heads are used in conventional blind rivets, then the mandrel can be discarded after setting, but the broken heads can cause rattling and shorting of electrical circuits and require additional quality checks
Solution Approach 1:
This invention extracts the problematic broken mandrel head from the system by pulling the entire mandrel head through the rivet body and out the far end. The mandrel head is no longer left broken in the rivet where it can cause rattling or shorting; instead, it emerges cleanly through the rivet, eliminating the reliability issues associated with broken mandrel heads while maintaining a relatively simple mandrel design without complex breakneck features.
3Duration of action of stationary object
If breakable mandrel heads are used in conventional blind rivets, then the mandrel can be separated from the rivet body, but the setting loads are high which reduces tool longevity and increases maintenance frequency
Solution Approach 1:
This invention employs dynamics by designing the mandrel with a tapered portion that gradually reduces in diameter toward the far end. During setting, the mandrel head is pulled through the rivet body, and the tapered geometry allows the mandrel to progressively engage and pull through the rivet material. This dynamic engagement distributes the setting force more effectively, reducing peak setting loads compared to breakable mandrel designs that require high forces to fracture the mandrel head, thereby extending tool longevity and reducing maintenance frequency.
Data Source
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AI summary
A blind rivet assembly is provided. In another aspect of the present invention, a blind rivet has ends that are received within countersinks in one or more workpieces and a mandrel head is completely pulled through the rivet without being severed from a mandrel stem. A further aspect of the present invention includes a mandrel with one or more ribs located on an outwardly tapering shoulder.