Self-Clinching Fastener Pilot Structure for Hollow Metal Tubes
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Solution Overview
Problem
Conventional self-attaching construction elements fail to provide sufficient rotational and push-out resistance when attached to complex metal substrates like hollow-metal tubes, often causing structural deformation of the substrate.
Innovation Solution
A self-clinching construction element with a body portion, punch portion, and pilot embossment designed to plastically deform and securely attach to metal substrates, featuring a recessed pocket and angled surfaces to enhance attachment strength and prevent rotation, suitable for both conventional and non-conventional substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional construction elements are attached to complex metal substrates like hollow-metal tubes, then attachment is achieved, but rotational and push-out resistance are insufficient and structural deformation occurs
Solution Approach 1:
The construction element is divided into distinct functional segments: a body portion for engagement, a punch portion for material displacement, and a pilot embossment for substrate interaction. This segmentation allows each portion to perform its specific function optimally without causing harmful effects to the substrate.
Solution Approach 2:
Different portions of the construction element have different geometric properties tailored to their specific functions. The pilot embossment has a smaller radius than the body portion, creating localized stress concentration points that guide material flow into the recessed pocket without deforming the entire substrate structure.
2Strength
If conventional construction elements are forced into metal substrates, then attachment is achieved, but rotational and push-out resistance are insufficient for complex geometries
Solution Approach 1:
The construction element design provides universal applicability to both conventional flat substrates and complex geometries like hollow-metal tubes. The combination of the body portion, punch portion, and pilot embossment creates a multi-functional element that adapts to different substrate types while maintaining high push-out resistance.
Solution Approach 2:
The recessed pocket creates a three-dimensional engagement feature that allows material to flow and lock in multiple directions. This dimensional complexity enables the element to achieve superior push-out resistance on substrates with varying geometries, including curved surfaces like hollow tubes.
3Strength
If conventional construction elements are forced into metal substrates, then attachment is achieved, but rotational resistance is insufficient
Solution Approach 1:
The pilot embossment creates an asymmetric engagement geometry with a smaller radius than the body portion. This asymmetry generates rotational resistance by creating a mechanical interlock where the deformed substrate material in the recessed pocket prevents rotation, while the overall element design remains relatively simple.
4Reliability
If conventional construction elements are attached to hollow-metal tubes, then attachment is achieved, but the substrate structural integrity is impaired
Solution Approach 1:
The pilot embossment performs a preliminary action by engaging the substrate first and guiding material flow into the recessed pocket before the main body portion is fully inserted. This preliminary material deformation prepares the substrate for secure engagement while minimizing the force required from the drive mechanism, thereby preserving substrate structural integrity.
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 self-clinching construction element achieves reliable attachment with sufficient push-out and rotational resistance without impairing the structural integrity of complex metal substrates, such as hollow-metal tubes, by allowing the substrate material to flow into the recessed pocket and conform to the element's geometry.
Implementation Method 1
configured to engage and plastically deform said metal substrate such that the metal substrate flows into the recessed pocket
Data Source
AI summary
A self-clinching and self-piercing construction element for attachment to a plastically deformable metal panel. The construction element includes a body portion with a central axis and a punch portion being coaxial with the central axis and extending from the body portion. A pilot embossment is coaxial with the central axis and extends from the body portion such that the pilot embossment is concentrically disposed between an annular-shaped surface of the body portion and the punch portion. The pilot embossment being configured to engage and plastically deform the metal substrate such that the metal substrate flows into a recessed pocket defined in an outer peripheral surface of the punch portion.