Compression Closure With Frustoconical Locking for High Transverse Force

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Solution Overview

Problem

Compression closures are limited in transmitting large forces due to friction-based force transmission, leading to potential slipping and wear, and require longer assembly processes compared to screw connections, which are often necessary for applications requiring repeated opening and closing.

Innovation Solution

A compression closure system featuring frusto-conical centering surfaces in a housing and counter-element, allowing for force-induced positive connections and increased static friction, enabling the transmission of large transverse forces while minimizing wear and assembly time, with a rotatable closure element and biasing elements like disc springs for preload generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If compression fasteners use friction-based force transmission, then assembly process is simple, but achievable forces are severely limited and slippage occurs

Engineering Contradiction:
Improveassembly simplicityVSAvoidtransmissible force
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The patent employs frustoconical (truncated conical) centering surfaces instead of cylindrical or flat surfaces. The conical geometry creates a wedge effect that converts axial compression forces into radial clamping forces, significantly increasing the frictional grip and transmissible force while maintaining the compression fastener's simple assembly process. This curved surface approach resolves the contradiction between assembly simplicity and force transmission capability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Force

If screw connections are used to transmit large forces, then force transmission capability increases, but assembly process requires longer time

Engineering Contradiction:
Improvetransmissible forceVSAvoidassembly time
Core Design Contradiction:
ForceVSLoss of time

Solution Approach 1:

The patent extracts the threading mechanism from the force transmission path. Instead of using threaded connections to both fasten and transmit force, the invention uses a simple compression mechanism with frustoconical surfaces for fastening, while force transmission is achieved through friction and mechanical interlocking of the conical surfaces. This separation allows rapid assembly without threading while maintaining high force transmission capability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If compression fasteners rely on friction, then assembly is quick, but wear increases and service life decreases

Engineering Contradiction:
Improveassembly speedVSAvoidservice life
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The frustoconical centering surfaces distribute contact stresses over a larger area and create more favorable stress distribution compared to flat or pointed contacts. The curved geometry reduces stress concentrations that lead to wear, while the wedge effect enhances frictional grip. This allows the fastener to maintain both quick assembly and extended service life by reducing wear rates.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Reliability

If frustoconical centering surfaces are used, then force-induced positive locking is achieved and degrees of freedom are removed, but manufacturing complexity increases

Engineering Contradiction:
Improveconnection stabilityVSAvoidgeometric complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into the frustoconical centering surfaces: they provide mechanical centering, force distribution, friction enhancement, and degree of freedom constraint simultaneously. This unified geometric feature achieves reliable connection stability without requiring separate complex mechanisms for each function, thereby limiting the increase in manufacturing complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 system effectively transmits large forces with reduced wear and assembly time, providing a secure, vibration-proof connection suitable for heavy cladding elements, and allows quick access and maintenance without the need for prolonged assembly processes.

Implementation Method 1

The compression closure according to the invention enables a force-induced positive closure as well as increased static friction compared to known systems

Methodology Applied
Scientific EffectStatic friction: Static Friction

Implementation Method 2

a prestressing force can be applied to the first frustoconical centering surface and the second frustoconical centering surface by the rotatably mounted closure element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4317714A1Compression closure
Publication Date: 2024.02.07 SIEMENS MOBILITY GMBH
  • EP4317714A1 patent drawingFigure 1
  • EP4317714A1 patent drawingFigure 2
  • EP4317714A1 patent drawingFigure 3

AI summary

According to the invention, a compression fastener 1, in particular for fastening a cladding element 2 to a bracket 3, is provided comprising a housing 10, a locking element 20 rotatably mounted within the housing 10, and a counter element 30 that can be engaged with the locking element 20. The housing 10 has a first frustoconic centering surface 12, and the counter element 30 has a second frustoconic centering surface 32 for applying a force-induced positive locking connection.