Protrusionless Blind Rivet Nut for Flush Axial Fixation
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Solution Overview
Problem
Existing blind rivet nuts and bolts protrude when set, causing interfering edges on workpieces, which is undesirable and adds expense, especially in thin materials where stability is compromised.
Innovation Solution
A blind rivet nut and bolt design with a setting area that can be enlarged radially without a protruding head, using a single force to create a friction or form fit within a workpiece recess, eliminating the need for countersinks and ensuring no or minimal protrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blind rivet nut with a setting head is used, then axial fixation is achieved, but a protruding edge is created on the workpiece
Solution Approach 1:
The setting area of the blind rivet nut is designed to be dynamically deformable under setting force, transitioning from a smaller initial state to an enlarged state that creates interference fit with the workpiece bore, eliminating the need for a protruding setting head
Solution Approach 2:
The outer dimension of the setting area is designed to change under applied force, allowing the blind rivet nut to expand radially and create a friction or form fit connection with the workpiece, thereby achieving axial fixation without protrusion
2Object-affected harmful factors
If a countersink is provided in the workpiece, then the blind rivet nut can be set flush, but additional manufacturing effort and reduced stability are required
Solution Approach 1:
The blind rivet nut performs its own setting function by enlarging its setting area under applied force to create interference fit directly within the existing bore, eliminating the need for separate countersinking operations
Solution Approach 2:
The blind rivet nut is designed with a setting area that can be enlarged during the setting process itself, preparing the interference fit condition in advance without requiring preliminary countersinking of the workpiece
3Object-affected harmful factors
If a countersink is provided in the workpiece, then the blind rivet nut can be set flush, but stability is compromised especially in thin workpieces
Solution Approach 1:
The enlargement of the setting area is localized to the blind rivet nut itself, creating interference fit only where needed without removing material from the workpiece, thereby maintaining the structural integrity and stability of thin workpieces
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 allows for secure axial fixation without protrusions, enhancing stability and reducing manufacturing costs by eliminating the need for countersinks, while maintaining the ability to connect workpieces effectively.
Implementation Method 1
the setting area on its free axial section facing away from the threaded area can be enlarged with respect to its outer dimension at least in a radial direction when a second force acting on it is exceeded
Implementation Method 2
an upsetting area, wherein the upsetting area is provided between the threaded area and the setting area and is designed to form a closing bead when a first force acting on it is exceeded
Implementation Method 3
a frictional and/or positive locking connection with the workpiece can be created
Data Source
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AI summary
The present invention relates to a blind rivet nut (105) and a blind rivet threaded stud for creating a thread in a recess of a workpiece and/or for joining two workpieces, wherein the blind rivet nut / blind rivet threaded stud comprises a setting area (110); a threaded area (120), wherein the threaded area has at least a partial internal thread (blind rivet nut) or an external thread (blind rivet threaded stud); an upsetting area, wherein the upsetting area is provided between the threaded area and the setting area and is designed to form a closing bead when a first force acting on it is exceeded, wherein the setting area has an axial section facing the upsetting area and a free axial section (112) facing away from the upsetting area;wherein the setting area on its free axial section facing away from the threaded area can be enlarged in at least one radial direction with respect to its outer dimension if a second force acting on it is exceeded. The blind rivet nut and the blind rivet threaded bolt are flush with the component after insertion/setting (protrusion = 0 mm).