Connection Element with Tapered Hole-Forming Portion
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Solution Overview
Problem
Existing connection elements, such as nails and flow drilling screws, face challenges in efficiently and reliably connecting light metal sheets without causing deformation or requiring excessive force, and often result in longer connection times.
Innovation Solution
A connection element with a shaft and a rotating drive configuration featuring closed annular protrusions and a tapered hole-forming portion, where the maximum external diameter of the hole-forming portion is 3-10% smaller than the annular protrusions, allowing for axial pressure-assisted insertion and subsequent locking through twisting, reducing deformation risk and connection time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a connection element is shot in axially through workpieces like a nail, then the connection is simple and fast, but large deformations occur in light metal sheets
Solution Approach 1:
The patent changes the physical state parameter of the material by heating it to a pasty or molten state during hole formation. This parameter change allows the material to flow around the holding portion and annular protrusions, creating a secure connection without requiring high impact forces that would deform light metal sheets. The material transitions from solid to pasty/molten and back to solid upon cooling, achieving both speed and precision.
Solution Approach 2:
The patent utilizes phase transition of the workpiece material from solid to pasty/molten state during the connection process. The heated material flows around the holding portion and solidifies upon cooling, creating a mechanical interlock. This phase transition enables the connection element to be inserted without high impact forces, preventing deformation of light metal sheets while maintaining connection speed.
2Force
If axial force is increased to push the holding portion into the hole, then insertion is achieved, but deformation of overlaid workpieces occurs
Solution Approach 1:
The patent changes the temperature parameter of the workpiece material, heating it to a pasty or molten state. This reduces the material's strength and increases its plasticity, allowing the holding portion to be pushed in with minor axial force without deforming the workpieces. The heated material also flows around the annular protrusions, providing mechanical interlock.
Solution Approach 2:
The patent utilizes phase transition of the workpiece material from solid to pasty/molten state through heating. This phase change reduces the material's resistance to deformation, enabling insertion with minor axial force. After insertion, the material cools and solidifies, locking the connection element in place without requiring high forces that would deform light metal sheets.
3Ease of operation
If the hole diameter matches the shaft external diameter, then easy insertion is achieved, but positive retention of annular protrusions is insufficient
Solution Approach 1:
The patent applies asymmetry by making the hole-forming portion's maximum external diameter different from the shaft's external diameter in the holding portion region. The hole diameter is designed to be slightly smaller than the shaft diameter, creating an interference fit that provides positive retention for the annular protrusions while still allowing insertion with minor axial force when the material is heated.
Solution Approach 2:
The patent utilizes thermal expansion by heating the workpiece material to expand it into a pasty or molten state, increasing the hole diameter temporarily to accommodate the shaft. After insertion, the material cools and contracts, creating a tight fit that retains the annular protrusions positively. This thermal expansion and contraction cycle enables both easy insertion and secure retention.
4Productivity
If connection time is reduced for efficiency, then productivity increases, but connection reliability may be compromised
Solution Approach 1:
The patent applies preliminary action by pre-heating the workpiece material in the hole-forming region before insertion of the holding portion. This preliminary heating softens the material, allowing rapid insertion with minor axial force and enabling quick locking through twisting. The pre-heated material flows around the annular protrusions during insertion, ensuring reliable anchoring is achieved quickly without compromising connection security.
Solution Approach 2:
The patent utilizes phase transition to achieve rapid connection with high reliability. The material is heated to a pasty or molten state for easy insertion and locking, then cools and solidifies quickly to provide strong retention. This phase transition process occurs rapidly, reducing connection time while ensuring the material fully solidifies to lock the connection element securely in place.
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 described connection element achieves reliable anchoring with minimal axial force, preventing deformation of light metal sheets and significantly reducing connection times compared to traditional methods, while ensuring secure locking and resistance to unscrewing.
Implementation Method 1
the hole, however, at least contracting during cooling and thus ensuring reliable anchoring of the annular protrusions
Implementation Method 2
the material that, after forming of the hole by means of the hole-forming portion, surrounds the formed hale is very hot and even at least in part molten or at least in a pasty state, respectively
Data Source
AI summary
The invention relates to a connection element for interconnecting at least two workpieces, having a shaft; a connection-element head, radially protruding beyond the external side of the shaft, at the one end of the shaft; a drive configuration on the connection-element head and a front shaft end, wherein in a holding portion of the shaft that emanates from the lower side of the connection-element head at least one pair of closed annular protrusions are disposed thereon, of which at least one annular protrusion is not completely disposed in a plane that runs perpendicularly to the longitudinal axis of the shaft; and the spacings between the two annular protrusions of the pair along the circumference are of dissimilar size, or the two annular protrusions of the pair of annular protrusions are disposed so as to be mutually parallel; wherein the front end of the shaft is configured as a tapered hole-forming portion, and wherein a maximum external diameter of the hole-forming portion is between 3% and 10% smaller, in particular 5% smaller, than a maximum external diameter of the annular protrusions.