Blind Rivet with Plastic Body and Guide Element
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Solution Overview
Problem
Existing blind rivets face challenges in uniform deformation during setting due to asymmetrical material stresses, leading to non-uniform contact with workpieces and limited holding and release forces, especially in applications like the automotive industry where easy removal is necessary without damaging surrounding components.
Innovation Solution
A blind rivet design featuring a guide element with radially inward projections and a conically expanding second region to ensure uniform deformation and secure mandrel locking, allowing for easy removal by reversing the mandrel and using a removal tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the rivet body is made of plastic with reduced wall thickness regions to enable deformation during setting, then the setting force efficiency and bead formation are improved, but the structural strength and resistance to damage during drilling-out deteriorate
Solution Approach 1:
The rivet body features regions with different wall thicknesses: a first region with reduced wall thickness for deformation and bead formation, and a second region with greater wall thickness for strength and damage resistance. This local differentiation allows the rivet to simultaneously achieve easy setting and resistance to drilling-out damage.
2Ease of operation
If the rivet body is designed to be removed in a single piece by reducing wall thickness, then the ease of removal is improved, but the holding forces and reliability of the joint deteriorate
Solution Approach 1:
The rivet body has a first region with reduced wall thickness that enables easy removal, while a second region with greater wall thickness maintains strong holding forces. This local differentiation allows the rivet to simultaneously achieve easy removal and reliable joint strength.
3Strength
If the mandrel is made of hard material for strong joining, then the joining strength is improved, but the difficulty of removing the rivet without damaging workpieces increases
Solution Approach 1:
The mandrel is designed with a predetermined breaking point that has reduced cross-section and strength. During removal, the mandrel breaks at this predetermined point rather than damaging the workpiece, allowing easy removal while maintaining strong joining during installation.
4Ease of manufacture
If the rivet body has asymmetric material stresses from molding, then the manufacturing ease is improved, but the uniformity of deformation and bead formation deteriorates
Solution Approach 1:
The rivet body is designed with intentional asymmetric features including a first region with reduced wall thickness and a second region with greater wall thickness. This asymmetric design compensates for asymmetric molding stresses, ensuring uniform deformation and consistent bead formation during setting.
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 design ensures a uniform annular bead formation, enhances setting force efficiency, and allows for easy single-piece removal without damaging workpieces, while maintaining strong axial contact pressure and seal integrity.
Implementation Method 1
a mandrel head that stands in operative connection with the foot end of the rivet body in order to transmit a force to the rivet body during setting of the blind rivet
Implementation Method 2
the rivet body deforms uniformly during setting of the blind rivet
Implementation Method 3
A blind rivet design featuring a guide element with radially inward projections and a conically expanding second region to ensure uniform deformation
Implementation Method 4
a conically expanding second region to ensure uniform deformation and secure mandrel locking
Implementation Method 5
enhances setting force efficiency, and allows for easy single-piece removal without damaging workpieces
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
In a blind rivet (10) having a hollow rivet body (11) made of plastic, having an elongated shank (13) with a bore (14), having a head (15) at one end of the shank and a foot end (19) on the opposite end of the shank (13), and having, located in the bore (14), a mandrel (12) that has a mandrel shank with a drawing end (38) and a mandrel head (35) that acts on the foot end (19), the shank (13) has a first region (21) located between the head (15) and the foot end (19), and has a second region (22) with reduced cross-section and reduced wall thickness as compared to the first region (21). The regions (21, 22) are arranged such that, as a result of a process in which the head (15) is pressed against one side of a workpiece and the foot end (19) is simultaneously drawn toward the other side of the workpiece with the aid of the mandrel (12), the wall of the shank (13) forms a roll fold with an annular bead. To avoid asymmetrical deformation, the shank (13) is guided by a guide element on the mandrel (12).