Radiused Screw Head Geometry for Low-Weight Torque Transmission

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Solution Overview

Problem

Existing screw elements are not optimized for low weight and flexibility, limiting their applicability in weight-sensitive and space-constrained applications such as passenger and commercial vehicles.

Innovation Solution

The screw element features corner domes with radiused flanks for compatibility with traditional hexagon sockets and surface drive mechanisms, and a central cup arrangement in the head to reduce weight and height, allowing for efficient torque transmission and flexible tool usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the screw element uses a traditional hexagon socket design, then it can be tightened with traditional box spanners, but the weight and height of the head are increased

Engineering Contradiction:
Improvetool compatibilityVSAvoidscrew element weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The head is segmented into corner domes separated by recesses, allowing material removal while maintaining structural integrity and tool engagement capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Material is extracted from the head to form recesses between corner domes, reducing weight while preserving the hexagon socket functionality for traditional tools

Inventive Principle:
Principle #2Taking out (Extraction)

2Weight of moving object

If the head height is reduced to lower weight, then weight decreases, but the structural integrity and torque transmission capability may be compromised

Engineering Contradiction:
Improvescrew element weightVSAvoidtorque transmission capability
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The corner domes are provided with radii on their flanks, creating curved surfaces that efficiently transmit torque while absorbing vertical forces, maintaining strength despite reduced head height

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The radii are specifically positioned on the flanks of corner domes where torque transmission occurs, providing localized strength enhancement without increasing overall head height

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the flanks of corner domes are provided with radii, then compatibility with surface drive mechanisms is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvesurface drive compatibilityVSAvoidmanufacturing simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The radii on the flanks of corner domes create curved surfaces that naturally engage with surface drive mechanisms, enabling universal tool compatibility through a single geometric feature

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Weight of moving object

If recesses are arranged between corner domes in the circumferential direction, then weight is reduced, but the tool engagement surface area is decreased

Engineering Contradiction:
Improvescrew element weightVSAvoidtool engagement surface area
Core Design Contradiction:
Weight of moving objectVSArea of stationary object

Solution Approach 1:

The head is divided into discrete corner domes separated by recesses, concentrating tool engagement surfaces on the domes while removing material from recess areas to reduce weight

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The corner domes with radiated flanks provide sufficient engagement surface area despite the presence of recesses, as the curved surfaces efficiently transmit torque

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP3080464B1Screw element having a tool engagement portion
Publication Date: 2021.05.26 FONTANA FASTENERS RD SRL
  • EP3080464B1 patent drawingFigure 1~2
  • EP3080464B1 patent drawingFigure 3~4
  • EP3080464B1 patent drawingFigure 5~7

AI summary

The invention relates to a screw element (10), comprising a shank (12) having a thread (14) and comprising a head (16) connected to the shank (12), the said head having a tool engagement portion (20) which has six corner domes (22) arranged evenly distributed in the peripheral direction of the head (16) and having respective flanks (24, 26), by which the head (16) can be brought into positive cooperation with a hexagon socket (34) of a tool (32) for tightening of the screw element (10), wherein respective recesses (38) are arranged peripherally between the comer domes (22), and wherein the flanks (24, 26) of the comer domes (22) are respectively provided at least partially with a radius (R).