Blind Rivet Shank Reinforcement for Head Formation
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Solution Overview
Problem
Existing blind rivets often damage joining elements, especially those made of plastic or soft metals like aluminum or copper, due to insufficient clamping and incorrect formation of the closing head, which can lead to material deformation and failure during the riveting process.
Innovation Solution
A blind rivet design featuring a reinforcement area within the shank that extends up to the minimum clamping area, allowing for controlled radial expansion and forming of the closing head, with a recess and ramps for improved stress distribution and guidance of the mandrel, preventing damage to the joining elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the shank is made with uniform wall thickness, then the manufacturing process is simple, but the closing head cannot be correctly formed and the joining element is damaged
Solution Approach 1:
The shank is designed with non-uniform wall thickness, featuring a reinforcement area with greater wall thickness than other sections. This local variation in structural properties allows the closing head to be correctly formed by providing adequate material strength at the critical location while maintaining simplicity elsewhere in the structure.
2Shape
If the shank radially expands during forming, then the closing head can be formed, but the joining element made of plastic or soft metal is damaged
Solution Approach 1:
The reinforcement area with increased wall thickness is positioned to extend to the minimum clamping area of the blind rivet. This localized strengthening prevents radial expansion of the shank within the reinforcement area, thereby preventing damage to the joining element while still allowing the closing head to form correctly in the non-reinforced sections.
3Volume of moving object
If the rivet head is small, then the rivet structure is compact, but the surface pressure is high and damages the joining element
Solution Approach 1:
By concentrating the additional material in the reinforcement area rather than uniformly increasing the entire shank, the design allows for a larger closing head to form at the critical location. This larger head distributes the surface pressure over a greater area, reducing damage to the joining element while keeping the overall rivet structure compact.
4Productivity
If the mandrel pulling force is applied without reinforcement, then the riveting process is fast, but the shank deforms incorrectly and the closing head does not form properly
Solution Approach 1:
The reinforcement area is pre-formed in the shank before the riveting process begins. This preliminary structural preparation ensures that when the mandrel pulling force is applied during setting, the shank has the necessary strength and geometry to deform correctly and form the closing head properly, maintaining both speed and precision.
Data Source
Figure 1~2
Figure 3
AI summary
A blind rivet (1) is specified, comprising a rivet sleeve with a shank (2), a setting head (3), and a closing head end (4), and a rivet mandrel (5). The aim is to provide a blind rivet suitable for a wide variety of applications. For this purpose, the shank (2) is provided with a reinforcement area (12) between the setting head (3) and the closing head end (4), extending to a maximum distance from the setting head (3) corresponding to the minimum clamping area of the blind rivet (1).