Rivet Fastening Spacer Gap Control
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Solution Overview
Problem
Existing rivet fastening methods require pre-processing deformation of the workpiece to accommodate the rivet section, which can be disruptive and necessitate additional steps, especially when dealing with varying dimensions or angled workpieces.
Innovation Solution
A fastening system that uses a spacer to maintain a defined gap between the workpiece and the die, allowing the rivet section to be shaped and engaged behind the workpiece without pre-processing, enabling direct fastening and adjustable gap width for different dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the workpiece is deformed to form a bead before rivet fastening, then a gap is created for the rivet section to engage behind the workpiece, but an additional pre-processing step is required and the workpiece surface becomes disrupted
Solution Approach 1:
The spacer is pre-installed on the die at a defined position before the fastening operation begins. This preliminary placement of the spacer creates the necessary gap condition in advance, eliminating the need for bead deformation as a preliminary action. The spacer maintains a predetermined distance between the die contact surface and the workpiece, ensuring the rivet section has sufficient space to engage behind the workpiece during fastening.
Solution Approach 2:
The spacer acts as an intermediary element between the die and the workpiece. Instead of directly deforming the workpiece to create engagement space, the spacer mediates the interaction by maintaining a controlled gap. This intermediary component transfers the function of gap creation from workpiece deformation to a dedicated positioning element, simplifying the overall process.
2Reliability
If the workpiece is deformed to form a bead, then space is provided for rivet section engagement, but the deformation must be adapted to specific rivet dimensions for each application
Solution Approach 1:
The spacer position on the die is made adjustable rather than fixed, allowing the gap width to be dynamically adapted to different rivet section dimensions. This dynamic positioning capability enables the same fastening system to accommodate various rivet types and sizes by simply repositioning the spacer, eliminating the need for bead deformation geometry to be re-engineered for each rivet specification.
Solution Approach 2:
The key parameter being changed is the spacer position distance from the die contact surface. By adjusting this dimensional parameter, the gap width is modified to match different rivet section requirements. This parameter change approach provides a simple and effective way to adapt the fastening process to various rivet dimensions without altering the fundamental deformation characteristics of the workpiece.
3Reliability
If bead deformation is applied to the workpiece, then the rivet section can engage behind the workpiece, but the bead projection interferes with workpiece positioning and removal from machining tools
Solution Approach 1:
The gap-creating function is extracted from the workpiece itself and transferred to the spacer component. Instead of modifying the workpiece by deforming it into a bead shape, the spacer is positioned to create the necessary engagement space. This extraction preserves the workpiece in its original flat state, eliminating the interfering bead projection while maintaining the rivet engagement capability.
Solution Approach 2:
Instead of deforming the workpiece to create engagement space, the approach is inverted by using a spacer to create space without deforming the workpiece. The conventional method transforms the workpiece geometry; the inverted method transforms the tooling configuration. This inversion maintains workpiece integrity and facilitates easier handling while achieving the same rivet engagement objective.
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
This method eliminates the need for pre-processing deformation, allows for precise gap definition, and supports fastening of rivet elements with varying dimensions, ensuring a reliable and form-fitting connection while maintaining a flat workpiece surface.
Implementation Method 1
the workpiece being held by means of the spacer at a well-defined distance from a contact surface of the die, so that a gap is formed between a wall of the hole and a punch of the die
Implementation Method 2
the rivet section is introduced into the gap and shaped by the punch in order to engage behind the workpiece in the area of the hole
Data Source
Figure 1a~1c
Figure 2a~2b
Figure 3
AI summary
The invention relates to a method for fastening a rivet element (10) to a workpiece (12) which has a pre-formed hole (26) for receiving a rivet section (32) of the rivet element and which is flat, at least in the area around the pre-formed hole. Before the fastening process, the workpiece is positioned at a well-defined distance (D) from a contact surface (18) of the die (14) by means of at least one spacer (16) which is fixedly connected to a die (14) for forming the rivet section (32) during the fastening process, so that a gap (30) is formed between a wall (28) of the hole (26) and a punch (24) of the die (14) provided for forming the rivet section (32). During the fastening process, the rivet section ( 32) is inserted into the gap (30) and deformed by the punch (24) to engage the workpiece (12) in the area of the hole (26).