Self-Drilling Screw With Elliptical Stop Section

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Solution Overview

Problem

Existing methods for insulating building envelopes, such as rear-ventilated metal façades, face challenges in simplifying the insulation process and avoiding thermal bridges, which complicates the efficient installation of insulation elements.

Innovation Solution

A screw design featuring a drive with a drill bit and a shank that includes a stop section with an elliptical or circular cross-section, allowing for tilted passage through a borehole when aligned parallel and blocking when perpendicular, facilitating the secure fastening of insulating elements between base and cover plates without pre-drilling requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional screw is used for fastening insulating elements, then the insulating element can be secured to the wall, but pre-drilling is required and the installation process becomes complex and time-consuming

Engineering Contradiction:
Improveease of installationVSAvoidinstallation process complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into a single screw component: the drill tip integrates with the shaft and stop section to create a self-drilling, self-positioning fastening system. The stop section with its specific geometry (elliptical or circular cross-section) merges the positioning function with the fastening function, eliminating the need for separate pre-drilling and positioning operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The screw performs self-service by automatically drilling its own path through the insulating element and positioning itself without external assistance. The stop section's geometry allows it to self-position at the correct depth and orientation, and the threaded shaft self-threads into the drilled hole, eliminating the need for pre-drilling and complex alignment procedures.

Inventive Principle:
Principle #25Self-service

2Reliability

If spacers and additional insulation panels are used to prevent thermal bridges, then thermal insulation performance improves, but the device complexity and installation time increase

Engineering Contradiction:
Improvethermal bridge preventionVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the thermal bridge prevention function from separate spacer components and integrates it directly into the screw's stop section. The stop section's geometry is designed to maintain the required distance between the insulating element and the wall, eliminating the need for separate spacer components while maintaining thermal insulation performance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The screw merges the fastening function with the thermal bridge prevention function by integrating the stop section into the shaft. This single component simultaneously secures the insulating element and maintains the air gap for thermal insulation, reducing the total number of components from multiple pieces (screw, spacer, insulation panel) to a single integrated screw.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If the stop section has an elliptical cross-section, then tilted passage through the borehole is enabled, but manufacturing precision requirements increase

Engineering Contradiction:
Improvetilted passage capabilityVSAvoidcross-section geometry precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies asymmetry by using an elliptical cross-section for the stop section instead of a circular one. This asymmetric geometry allows the stop section to pass through the borehole at tilted angles during installation, providing adaptability to various installation conditions. The elliptical shape has different dimensions in different directions, enabling it to clear the borehole walls at oblique angles while still providing effective stopping when aligned properly.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3066349B1Screw, building cladding and insulating method
Publication Date: 2019.07.03 HILTI AG
  • EP3066349B1 patent drawingFigure 1
  • EP3066349B1 patent drawingFigure 2

AI summary

The invention relates to a screw, comprising a drive, a drilling tip for producing a bore, said bore having a bore axis and a bore diameter, which drilling tip is spaced apart from the drive in a drive-in direction, and a shaft, which extends from the drive to the drilling tip, wherein the shaft has a stop section, which can be fed through the bore when the drive-in direction of the screw is tilted in relation to the bore axis and which has a stop surface for blocking the feeding of the stop section through the bore when the drive-in direction of the screw is oriented parallel to the bore axis.