Conical Wavy Flange Screw for Preload Maintenance

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Solution Overview

Problem

Existing screw designs with conical, corrugated flanges struggle to maintain sufficient preload force over a wide range of conditions, particularly under temperature changes, due to limited cushioning and locking mechanisms.

Innovation Solution

The screw features side surfaces that run continuously conically from the shank to the outer edge of the flange with decreasing thickness and a corrugation extending across the entire radial width, along with support knobs or locking teeth, allowing for enhanced preload force maintenance and secure locking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the flange has a flat side surface with a notch and limited corrugation area, then the screw can impact the component and prevent further screwing, but the scope for cushioning is limited and preload force cannot be maintained over wide temperature ranges

Engineering Contradiction:
Improvepreload force maintenanceVSAvoidtemperature range adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The flange is designed with varying local properties: the inner half has a flat side surface for initial impact and positioning, while the outer half features corrugation for cushioning and elastic deformation. This local differentiation allows the flange to provide both precise positioning and adaptive cushioning across temperature ranges.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The continuously conical side surfaces enable the flange to dynamically adapt its deformation characteristics during tightening. As the flange bends elastically during installation and under thermal expansion/contraction, the conical geometry provides a progressive mechanical response that maintains preload force across varying conditions.

Inventive Principle:
Principle #15Dynamics

2Force

If the flange thickness decreases outwards with continuous conical side surfaces, then the scope for cushioning and preload force range is increased, but the structural complexity of the flange geometry increases

Engineering Contradiction:
Improvepreload force scopeVSAvoidflange geometry complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The flange employs continuous conical side surfaces that curve smoothly from the screw shank to the outer edge, eliminating sharp transitions and discrete steps. This curved geometry provides a progressive thickness reduction that increases cushioning scope while maintaining manufacturability through standard forming processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Strength

If the corrugation extends over the entire radial width of the flange, then the cushioning scope is significantly increased, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvecushioning capabilityVSAvoidcorrugation uniformity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The corrugation parameters (amplitude, wavelength, depth) are optimized to provide sufficient cushioning while remaining within standard manufacturing tolerances. The corrugation extends over the entire radial width with controlled parameters that balance cushioning effectiveness with manufacturability using conventional forming techniques.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If support knobs are added to the side surface facing the component, then locking capability and screwing-in control are improved, but the device complexity increases

Engineering Contradiction:
Improvelocking capabilityVSAvoidflange feature complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The flange side surface is segmented into functional zones: support knobs are distributed around the circumference to provide localized locking points and control screwing-in progress, while the continuously conical side surfaces provide overall structural integrity and cushioning. This segmentation achieves enhanced locking without requiring complex additional components.

Inventive Principle:
Principle #1Segmentation

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 design significantly increases the scope for cushioning and locking, ensuring the screw connection maintains tension and binding force over varying conditions, including temperature changes, and allows for adjustable preload force settings.

Implementation Method 1

tension is maintained over a wide range via the bending of the flange itself as well as the return of the corrugation to a more stretched position

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

when the screw is tightened, tension is maintained over a wide range via the bending of the flange itself as well as the return of the corrugation to a more stretched position

Methodology Applied
Scientific EffectImpact force: Impact Force

Implementation Method 3

the two side surfaces of the flange run continuously conically from the screw shank to the outer edge of the flange, with the thickness of the flange decreasing outwards

Methodology Applied
Scientific EffectConical deformation: Deformation

Data Source

PatentEP2649329B1Screw having a screw head, a screw shaft, and a conical, wavy flange
Publication Date: 2015.08.05 EJOT GMBH & CO KG
  • EP2649329B1 patent drawingFigure 1~5

AI summary

The invention relates to a screw having a screw head (2), a screw shaft (1), and a conical, wavy flange (4) of decreasing thickness toward the outside, contacting a component when the screw is threaded into said component. The two side surfaces (5, 6) of the flange (4) from the screw shaft (1) to the outer edge (7) of the flange run continuously conically from the outside inward as the thickness of the flange (4) decreases, wherein the waviness (8) thereof extends substantially over the entire radial width of the flange (4).