Rivet Nut U-Shaped Groove for Flush Sheet Metal
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Solution Overview
Problem
Existing rivet nut designs for sheet metal parts often result in a protruding rivet flange, which can create a non-flat surface and require additional components like washers, and do not effectively accommodate varying sheet metal thicknesses without increasing the rivet nut size.
Innovation Solution
A rivet nut with a U-shaped annular groove and anti-rotation ribs that allows the rivet flange to sit flush with the sheet metal surface, accommodating a range of sheet thicknesses by adjusting the groove's volume and rib height, ensuring a strong and flat attachment without protrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the rivet nut uses a conventional annular groove design, then the rivet flange protrudes beyond the sheet metal surface, but the overall height increases and a non-flat surface is created
Solution Approach 1:
The patent applies parameter changes by modifying the annular groove geometry from a conventional design to a U-shaped cross-section with a steep radially outer side wall at approximately 45° inclination. This specific geometric parameter change allows the rivet flange to sit flush with the sheet metal surface, achieving a flat appearance without increasing overall height. The controlled volume of the groove also ensures the folded rivet section accommodates properly within the sheet thickness range.
2Adaptability or versatility
If the rivet nut is designed for thin sheet metal, then the attachment strength is sufficient, but the design does not accommodate varying sheet thicknesses effectively
Solution Approach 1:
The patent implements universality by designing a single rivet nut configuration that can accommodate a range of sheet metal thicknesses (0.6mm to 2.5mm) without requiring different rivet nut lengths or shapes. The U-shaped annular groove with controlled volume and the anti-rotation ribs work together to provide effective attachment across this thickness range, making the rivet nut design universal for various sheet thicknesses while maintaining adequate attachment strength.
3Adaptability or versatility
If the annular groove volume is increased to accommodate thicker sheets, then the adaptability improves, but the rivet flange may protrude beyond the sheet surface
Solution Approach 1:
The patent applies local quality by creating a specific U-shaped groove geometry with a steep radially outer side wall at approximately 45° inclination. This localized geometric feature ensures that the folded rivet section is contained within the groove volume appropriate for the sheet thickness, preventing flange protrusion. The anti-rotation ribs positioned within the groove further ensure proper material containment and folding behavior, achieving both adaptability and flush surface quality simultaneously.
Data Source
Figure 1A~1D
Figure 2A~2F
Figure 3A~3D
AI summary
The invention relates to a rivet nut with a base part and a cylindrical rivet section, the base part having a central threaded cylinder, an annular contact surface that is coaxial to the threaded cylinder in a plane perpendicular to the longitudinal axis of the threaded cylinder, and that has an axially aligned annular groove, said groove being arranged radially inside the annular contact surface and radially outside the cylindrical rivet section and said groove blending, on the radially inner side, into the outer surface of the cylindrical rivet section, and antirotation ribs being provided in the area of the annular groove. The invention is characterized in that the annular groove, when seen in an axial cross-sectional plane, has a U-shaped cross-section with a radially outer lateral wall which is relatively steep and which has, at the steepest point, an inclination to the center longitudinal axis of the rivet nut in the range of approximately 45° to approximately -20°, preferably of approximately 30° to approximately 0°. The volume of the annular groove is chosen in such a manner that across a range of sheet thicknesses adapted to the respective thread size there is room for the volume of the respective folded region of the rivet section inside the annular recess that is formed by molding the sheet part into the annular groove of the element and that it does not project beyond the side of the molded sheet facing away from the annular contact surface.