Tamperproof Screw Coupling for Thermal Plant Valves

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Solution Overview

Problem

Existing air venting and safety valves in thermal/sanitary plants face risks due to loosening of clamping torque between cap and cup elements, especially in technopolymer materials, leading to potential safety hazards from high pressures and unintended unscrewing, which current solutions like adhesives are inefficient and costly to address.

Innovation Solution

A tamperproof screwing coupling system featuring locking means with notched circular portions and stop protruding portions on cap and cup elements, allowing screwing while preventing unscrewing, utilizing a ratchet-like mechanism with tooth-shaped protrusions and sliding surfaces to secure the connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple screwing connection is used between cap and cup body, then the device complexity is reduced and ease of manufacture is improved, but the reliability deteriorates due to loosening of clamping torque under pressure and temperature changes

Engineering Contradiction:
Improvecoupling structureVSAvoidclamping torque stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The coupling system employs asymmetric toothed profiles where the locking teeth on the cap have a specific geometry that engages with corresponding teeth on the cup body. The asymmetric design allows easy screwing in one direction while preventing unscrewing, as the teeth interlock in a way that resists reverse rotation under pressure and temperature variations.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The coupling system incorporates a preliminary locking action through the toothed engagement that occurs before full tightening. The interlocking teeth establish a preliminary mechanical lock that prevents loosening from the outset, rather than relying solely on friction from clamping torque that may degrade over time.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If adhesive measures are applied to prevent unscrewing, then the reliability is improved, but the ease of manufacture deteriorates and cost increases

Engineering Contradiction:
Improveconnection stabilityVSAvoidassembly process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention replaces the chemical bonding approach (adhesives) with a purely mechanical locking system. The toothed coupling mechanism provides reliable prevention of unscrewing through mechanical interlocking, eliminating the need for adhesive application, curing time, and specialized assembly procedures while maintaining connection stability under varying operating conditions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a tamperproof locking mechanism is implemented, then the reliability is improved by preventing unintended unscrewing, but the ease of operation deteriorates due to inability to remove cap

Engineering Contradiction:
Improveprotection against unscrewingVSAvoidcap removal
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The coupling system implements preliminary anti-action by designing the toothed engagement to automatically prevent unscrewing movements. The interlocking teeth create a mechanical barrier that opposes any attempt at reverse rotation, protecting against both accidental loosening and intentional tampering, while still allowing proper installation through the screwing direction.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP2954241B1Tamperproof screwing coupling system for valve of a thermal/sanitary plant for buildings
Publication Date: 2018.04.11 CALEFFI
  • EP2954241B1 patent drawingFigure 1~2a
  • EP2954241B1 patent drawingFigure 3~4a
  • EP2954241B1 patent drawingFigure 5~5a

AI summary

A tamperproof screwing coupling system for valve (102) of a thermal/ sanitary plant for buildings comprises: - a first connecting part (3) and a second connecting part (4) that are mutually couplable through screwing by relative rotation of the first connecting part(3) with respect to the second connecting part (4) around an axis (X) and, - locking means provided on the first part (3) and on the second connecting part (4), arranged to allow such connecting parts to be mutually screwed to a clamping configuration (S), and configured to mutually lock the first connecting part (3) and the second connecting part (4) in the clamping configuration (S), thus preventing a relative unscrewing movement thereof.